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271.
Mariana D. Cuozzo Fernando A. Frieiro-Costa Brígida Souza 《Journal of Natural History》2017,51(9-10):531-543
Cassidinae Gyllenhaal? is the second largest subfamily of Chrysomelidae (Coleoptera), which presents characteristic morphology, biology and behaviour. The current study describes the life cycle of Paraselenis(Spaetiechoma) dichroa (Germar), ?determining biological and behavioural aspects as well as the action of natural enemies on populations, when the species has maternal care. The study was conducted between February and April 2015 in the National Forest of Passa Quatro, municipality of Passa Quatro, Minas Gerais state, Brazil. Daily observations were made (morning and afternoon) to evaluate the offspring of females on Ipomoea sp. and Merremia macrocalyx (O’Donell?) (Convolvulaceae), as well as the actions of natural enemies on the young. The eggs are deposited on the midrib and abaxial surface of leaves (n = 25). Egg clusters are pedunculated, arranged in groups and devoid of any cover. On average, each female produced 27.3 ± 5.6 (n = 16) eggs, with a mean incubation period of 12.7 ± 2.9 days (n = 10 females with their young). The larvae remained grouped in the leaves throughout development, except when they fed. They retained faeces and exuviae as a stacked faecal structure on their mobile urogomphi (caudal process) like a faecal shield. The mean number of larvae per female was 12.7 ± 10.1 (n = 19) and the larval period lasted 24.9 ± 4.5 days (n = 12). Pupation occurred on the stem of the plant (n = 16). On average there were 8.1 ± 8.5 individuals for pupae progeny (n = 14). The mean duration of the pupal stage was 10.4 ± 3.3 days (n = 5). Overall, 3% of adults emerged (n = 13 individuals), with a total cycle time of 41.3 ± 8.4 days (n = 6). Adults are sexually dimorphic in the elytral shape. Females remain with the offspring throughout development. The natural enemies of immatures were Emersonella pubipennis Hansson? (Hymenoptera: Eulophidae), Tachinidae (Diptera) and Stiretrus decastigmus (Herrich-Schaeffer?) (Heteroptera: Pentatomidae), Conura sp. Spinola? (Hymenoptera: Chalcididae) and Brachymeria sp. Westwood? (Hymenoptera: Chalcididae). The information presented here on the natural history of P. dichroa are important as they may serve as a starting point to understand evolutionary questions and multispecies interactions. 相似文献
272.
Rafaela Lacerda Juliane Menezes Luísa Romão 《Cellular and molecular life sciences : CMLS》2017,74(9):1659-1680
The scanning model for eukaryotic mRNA translation initiation states that the small ribosomal subunit, along with initiation factors, binds at the cap structure at the 5′ end of the mRNA and scans the 5′ untranslated region (5′UTR) until an initiation codon is found. However, under conditions that impair canonical cap-dependent translation, the synthesis of some proteins is kept by alternative mechanisms that are required for cell survival and stress recovery. Alternative modes of translation initiation include cap- and/or scanning-independent mechanisms of ribosomal recruitment. In most cap-independent translation initiation events there is a direct recruitment of the 40S ribosome into a position upstream, or directly at, the initiation codon via a specific internal ribosome entry site (IRES) element in the 5′UTR. Yet, in some cellular mRNAs, a different translation initiation mechanism that is neither cap- nor IRES-dependent seems to occur through a special RNA structure called cap-independent translational enhancer (CITE). Recent evidence uncovered a distinct mechanism through which mRNAs containing N 6-methyladenosine (m6A) residues in their 5′UTR directly bind eukaryotic initiation factor 3 (eIF3) and the 40S ribosomal subunit in order to initiate translation in the absence of the cap-binding proteins. This review focuses on the important role of cap-independent translation mechanisms in human cells and how these alternative mechanisms can either act individually or cooperate with other cis-acting RNA regulons to orchestrate specific translational responses triggered upon several cellular stress states, and diseases such as cancer. Elucidation of these non-canonical mechanisms reveals the complexity of translational control and points out their potential as prospective novel therapeutic targets. 相似文献
273.
Alejandra A. Covarrubias Cesar L. Cuevas-Velazquez Paulette S. Romero-Pérez David F. Rendón-Luna Caspar C. C. Chater 《Cellular and molecular life sciences : CMLS》2017,74(17):3119-3147
Plants are sessile organisms. This intriguing nature provokes the question of how they survive despite the continual perturbations caused by their constantly changing environment. The large amount of knowledge accumulated to date demonstrates the fascinating dynamic and plastic mechanisms, which underpin the diverse strategies selected in plants in response to the fluctuating environment. This phenotypic plasticity requires an efficient integration of external cues to their growth and developmental programs that can only be achieved through the dynamic and interactive coordination of various signaling networks. Given the versatility of intrinsic structural disorder within proteins, this feature appears as one of the leading characters of such complex functional circuits, critical for plant adaptation and survival in their wild habitats. In this review, we present information of those intrinsically disordered proteins (IDPs) from plants for which their high level of predicted structural disorder has been correlated with a particular function, or where there is experimental evidence linking this structural feature with its protein function. Using examples of plant IDPs involved in the control of cell cycle, metabolism, hormonal signaling and regulation of gene expression, development and responses to stress, we demonstrate the critical importance of IDPs throughout the life of the plant. 相似文献
274.
S. Padilla U. C. Tran M. Jiménez-Hidalgo J. M. López-Martín A. Martín-Montalvo C. F. Clarke P. Navas C. Santos-Ocaña 《Cellular and molecular life sciences : CMLS》2009,66(1):173-186
Coenzyme Q is a lipid molecule required for respiration and antioxidant protection. Q biosynthesis in Saccharomyces cerevisiae requires nine proteins (Coq1p–Coq9p). We demonstrate in this study that Q levels are modulated during growth by its conversion
from demethoxy-Q (DMQ), a late intermediate. Similar conversion was produced when cells were subjected to oxidative stress
conditions. Changes in Q6/DMQ6 ratio were accompanied by changes in COQ7 gene mRNA levels encoding the protein responsible for the DMQ hydroxylation, the penultimate step in Q biosynthesis pathway.
Yeast coq null mutant failed to accumulate any Q late biosynthetic intermediate. However, in coq7 mutants the addition of exogenous Q produces the DMQ synthesis. Similar effect was produced by over-expressing ABC1/COQ8. These results support the existence of a biosynthetic complex that allows the DMQ6 accumulation and suggest that Coq7p is a control point for the Q biosynthesis regulation in yeast.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Received 04 September 2008; received after revision 22 October 2008; accepted 23 October 2008 相似文献
275.
Martínez-Salgado C Rodríguez-Peña AB López-Novoa JM 《Cellular and molecular life sciences : CMLS》2008,65(3):477-492
The mechanisms involved in the development of renal fibrosis are poorly understood. Small Ras GTPases control cell proliferation,
differentiation, cellular growth and apoptosis, with cell-specific expression in the kidney. Cytokines, high glucose medium
or advanced glycation end-products activate Ras in different renal cells. Increased Ras activation has been found in experimental
tubulointerstitial fibrosis. Transforming growth factor-β1 (TGF-β1) and Ras signalling pathways are close related: TGF-β1
overcomes Ras mitogenic effects, and Ras counteracts TGF-β signalling. However, Ras activation is also an intracellular signal
transduction point for several molecules (e.g. TGF-β1) involved in kidney damage. Ras isoforms play different roles in regulating extracellular matrix synthesis in fibroblasts
and mesangial cells. These data give evidence for a role for Ras in renal fibrosis, but no reviews are available on the role
of p21 Ras in this process. Thus, our goal is to review the role of Ras activation and signalling in renal fibrosis.
Received 7 June 2007; received after revision 17 September 2007; accepted 1 October 2007 相似文献
276.
Carballar-Lejarazú R Rodríguez MH de la Cruz Hernández-Hernández F Ramos-Castañeda J Possani LD Zurita-Ortega M Reynaud-Garza E Hernández-Rivas R Loukeris T Lycett G Lanz-Mendoza H 《Cellular and molecular life sciences : CMLS》2008,65(19):3081-3092
Scorpine is an antimicrobial peptide whose structure resembles a hybrid between a defensin and a cecropin. It exhibits antibacterial
activity and inhibits the sporogonic development of parasites responsible for murine malaria. In this communication we report
the production of scorpine in a heterelogous system, using a specific vector containing its cloned gene. The recombinantly
expressed scorpine (RScp) in Anopheles gambie cells showed antibacterial activity against Bacillus subtilis and Klebsiella pneumoniae, at 5 and 10 μM, respectively. It also produced 98% mortality in sexual stages of Plasmodium berghei at 15 μM and 100% reduction in Plasmodium falciparum parasitemia at 5 μM. RScp also inhibited virus dengue-2 replication in C6/36 mosquito cells. In addition, we generated viable
and fertile transgenic Drosophila that overexpresses and correctly secretes RScp into the insect hemolymph, suggesting that the generation of transgenic mosquitoes
resistant to different pathogens may be viable.
Received 6 May 2008; received after revision 24 July 2008; accepted 29 July 2008 相似文献
277.
Irigoyen M Ansó E Salvo E Dotor de las Herrerías J Martínez-Irujo JJ Rouzaut A 《Cellular and molecular life sciences : CMLS》2008,65(14):2244-2255
TGFbeta-induced protein (TGFBI) is an extracellular protein that mediates cell adhesion to collagen, laminin and fibronectin through its interaction with different beta integrins. We had previously reported that hypoxia-induced TGFBI mRNA expression in lymphatic endothelial cells (LEC). Here, we demonstrate that TGFBI can contribute to hypoxia-induced increases in LEC adhesion to the ECM. We show that while there are no changes in alpha1, alpha4, alphav, beta1, beta2, beta3, alpha5beta1, alphavbeta3, alphavbeta5 integrin expression on the LEC surface after hypoxia exposure, there exists an accumulation of TGFBI adaptor protein in LEC supernatants. We also demonstrate that hypoxia driven TGBFI expression is dependent on TGFbeta production by LEC. Furthermore, we show that TGFBI mediated LEC adhesion and migration through the ECM by its binding to the beta3 integrin. The identification of the specific mechanisms regulating LEC-ECM interactions may help us design new therapeutic applications for diseases in which lymphatic vessel function is compromised. 相似文献
278.
Heras SR Thomas MC García-Canadas M de Felipe P García-Pérez JL Ryan MD López MC 《Cellular and molecular life sciences : CMLS》2006,63(12):1449-1460
A comparative analysis of 40 Trypanosoma cruzi L1Tc elements showed that the 2A self-cleaving sequence described in viruses is present in them. Of these elements, 72% maintain
the canonical 2A motif (DxExNPGP). A high percentage has a conserved point mutation within the motif that has not been previously
described. In vitro and in vivo expression of reporter polyproteins showed that the L1Tc2A sequence is functional. Mutations within certain L1Tc2A sequences
affect the efficiency of the cleavage. The data indicate that the L1Tc2A sequence may be influencing the L1Tc enzymatic machinery
determining the composition and level of the translated products. The residues located immediately upstream of the 2A consensus
sequence increase the cleaving efficiency and appear to stabilize the relative amount of translated products.
These authors contributed equally to this work.
Received 26 January 2006; received after revision 11 April 2006; accepted 21 April 2006 相似文献
279.
Ortega Z Díaz-Hernández M Lucas JJ 《Cellular and molecular life sciences : CMLS》2007,64(17):2245-2257
Ubiquitylated inclusion bodies (IBs) found in Huntington’s disease (HD) postulate an impaired ubiquitin-proteasome system.
However, this hypothesis remains controversial. In vitro-generated polyglutamine aggregates failed to inhibit purified proteasomes, while filamentous huntingtin aggregates isolated
from mice resulted in inhibition. However, similarly isolated IBs did not, thus suggesting that IB formation is protective
by sequestering smaller inhibitory aggregates. Accordingly, proteasome-activity assays in IB-containing mouse brain homogenates
did not show decreased activity. On the contrary, some of the endoproteolytic proteasome activities increased, probably due
to altered subunit composition. However, activity was found decreased in postmortem human HD tissue. Finally, evidence supporting
the hypothesis was found in HD cell models expressing fluorescent ubiquitin-proteasome system reporters but not in retina
of SCA-7 mice with similar reporters. In summary, it seems that mutant huntingtin, probably in intermediate aggregate forms,
has the potential to inhibit proteasome activity, but the global status of the system in HD brain tissue is not yet fully
elucidated. 相似文献
280.
Pujana MA Han JD Starita LM Stevens KN Tewari M Ahn JS Rennert G Moreno V Kirchhoff T Gold B Assmann V Elshamy WM Rual JF Levine D Rozek LS Gelman RS Gunsalus KC Greenberg RA Sobhian B Bertin N Venkatesan K Ayivi-Guedehoussou N Solé X Hernández P Lázaro C Nathanson KL Weber BL Cusick ME Hill DE Offit K Livingston DM Gruber SB Parvin JD Vidal M 《Nature genetics》2007,39(11):1338-1349
Many cancer-associated genes remain to be identified to clarify the underlying molecular mechanisms of cancer susceptibility and progression. Better understanding is also required of how mutations in cancer genes affect their products in the context of complex cellular networks. Here we have used a network modeling strategy to identify genes potentially associated with higher risk of breast cancer. Starting with four known genes encoding tumor suppressors of breast cancer, we combined gene expression profiling with functional genomic and proteomic (or 'omic') data from various species to generate a network containing 118 genes linked by 866 potential functional associations. This network shows higher connectivity than expected by chance, suggesting that its components function in biologically related pathways. One of the components of the network is HMMR, encoding a centrosome subunit, for which we demonstrate previously unknown functional associations with the breast cancer-associated gene BRCA1. Two case-control studies of incident breast cancer indicate that the HMMR locus is associated with higher risk of breast cancer in humans. Our network modeling strategy should be useful for the discovery of additional cancer-associated genes. 相似文献