全文获取类型
收费全文 | 8348篇 |
免费 | 103篇 |
国内免费 | 45篇 |
专业分类
系统科学 | 146篇 |
丛书文集 | 60篇 |
教育与普及 | 6篇 |
理论与方法论 | 45篇 |
现状及发展 | 3550篇 |
研究方法 | 290篇 |
综合类 | 4320篇 |
自然研究 | 79篇 |
出版年
2016年 | 52篇 |
2015年 | 80篇 |
2013年 | 43篇 |
2012年 | 218篇 |
2011年 | 305篇 |
2008年 | 113篇 |
2007年 | 139篇 |
2006年 | 128篇 |
2005年 | 303篇 |
2004年 | 608篇 |
2003年 | 558篇 |
2002年 | 250篇 |
2001年 | 229篇 |
2000年 | 310篇 |
1999年 | 173篇 |
1992年 | 127篇 |
1991年 | 93篇 |
1990年 | 105篇 |
1989年 | 95篇 |
1988年 | 81篇 |
1987年 | 86篇 |
1986年 | 94篇 |
1985年 | 158篇 |
1984年 | 98篇 |
1983年 | 89篇 |
1982年 | 75篇 |
1981年 | 72篇 |
1980年 | 85篇 |
1979年 | 191篇 |
1978年 | 159篇 |
1977年 | 161篇 |
1976年 | 149篇 |
1975年 | 169篇 |
1974年 | 196篇 |
1973年 | 156篇 |
1972年 | 151篇 |
1971年 | 211篇 |
1970年 | 276篇 |
1969年 | 216篇 |
1968年 | 194篇 |
1967年 | 201篇 |
1966年 | 175篇 |
1965年 | 121篇 |
1964年 | 57篇 |
1959年 | 67篇 |
1958年 | 82篇 |
1957年 | 81篇 |
1956年 | 52篇 |
1955年 | 48篇 |
1954年 | 54篇 |
排序方式: 共有8496条查询结果,搜索用时 15 毫秒
131.
Sophie M. Hapak Carla V. Rothlin Sourav Ghosh 《Cellular and molecular life sciences : CMLS》2018,75(15):2735-2761
Polarity is a fundamental feature of cells. Protein complexes, including the PAR3–PAR6–aPKC complex, have conserved roles in establishing polarity across a number of eukaryotic cell types. In neurons, polarity is evident as distinct axonal versus dendritic domains. The PAR3, PAR6, and aPKC proteins also play important roles in neuronal polarization. During this process, either aPKC kinase activity, the assembly of the PAR3–PAR6–aPKC complex or the localization of these proteins is regulated downstream of a number of signaling pathways. In turn, the PAR3, PAR6, and aPKC proteins control various effector molecules to establish neuronal polarity. Herein, we discuss the many signaling mechanisms and effector functions that have been linked to PAR3, PAR6, and aPKC during the establishment of neuronal polarity. 相似文献
132.
Potassium and sodium transport in non-animal cells: the Trk/Ktr/HKT transporter family 总被引:1,自引:1,他引:0
C. Corratgé-Faillie M. Jabnoune S. Zimmermann A.-A. Véry C. Fizames H. Sentenac 《Cellular and molecular life sciences : CMLS》2010,67(15):2511-2532
Bacterial Trk and Ktr, fungal Trk and plant HKT form a family of membrane transporters permeable to K+ and/or Na+ and characterized by a common structure probably derived from an ancestral K+ channel subunit. This transporter family, specific of non-animal cells, displays a large diversity in terms of ionic permeability,
affinity and energetic coupling (H+–K+ or Na+–K+ symport, K+ or Na+ uniport), which might reflect a high need for adaptation in organisms living in fluctuating or dilute environments. Trk/Ktr/HKT
transporters are involved in diverse functions, from K+ or Na+ uptake to membrane potential control, adaptation to osmotic or salt stress, or Na+ recirculation from shoots to roots in plants. Structural analyses of bacterial Ktr point to multimeric structures physically
interacting with regulatory subunits. Elucidation of Trk/Ktr/HKT protein structures along with characterization of mutated
transporters could highlight functional and evolutionary relationships between ion channels and transporters displaying channel-like
features. 相似文献
133.
Alcázar R García AV Kronholm I de Meaux J Koornneef M Parker JE Reymond M 《Nature genetics》2010,42(12):1135-1139
Accumulation of genetic incompatibilities within species can lead to reproductive isolation and, potentially, speciation. In this study, we show that allelic variation at SRF3 (Strubbelig Receptor Family 3), encoding a receptor-like kinase, conditions the occurrence of incompatibility between Arabidopsis thaliana accessions. The geographical distribution of SRF3 alleles reveals that allelic forms causing epistatic incompatibility with a Landsberg erecta allele at the RPP1 resistance locus are present in A. thaliana accessions in central Asia. Incompatible SRF3 alleles condition for an enhanced early immune response to pathogens as compared to the resistance-dampening effect of compatible SRF3 forms in isogenic backgrounds. Variation in disease susceptibility suggests a basis for the molecular patterns of a recent selective sweep detected at the SRF3 locus in central Asian populations. 相似文献
134.
Gauthier LR Granotier C Hoffschir F Etienne O Ayouaz A Desmaze C Mailliet P Biard DS Boussin FD 《Cellular and molecular life sciences : CMLS》2012,69(4):629-640
Functional telomeres are protected from non-homologous end-joining (NHEJ) and homologous recombination (HR) DNA repair pathways.
Replication is a critical period for telomeres because of the requirement for reconstitution of functional protected telomere
conformations, a process that involves DNA repair proteins. Using knockdown of DNA-PKcs and Rad51 expression in three different
cell lines, we demonstrate the respective involvement of NHEJ and HR in the formation of telomere aberrations induced by the
G-quadruplex ligand 360A during or after replication. HR contributed to specific chromatid-type aberrations (telomere losses
and doublets) affecting the lagging strand telomeres, whereas DNA-PKcs-dependent NHEJ was responsible for sister telomere
fusions as a direct consequence of G-quadruplex formation and/or stabilization induced by 360A on parental telomere G strands.
NHEJ and HR activation at telomeres altered mitotic progression in treated cells. In particular, NHEJ-mediated sister telomere
fusions were associated with altered metaphase-anaphase transition and anaphase bridges and resulted in cell death during
mitosis or early G1. Collectively, these data elucidate specific molecular and cellular mechanisms triggered by telomere targeting
by the G-quadruplex ligand 360A, leading to cancer cell death. 相似文献
135.
Voltage-gated calcium channels are important mediators of calcium influx into electrically excitable cells. The amount of
calcium entering through this family of channel proteins is not only determined by the functional properties of channels embedded
in the plasma membrane but also by the numbers of channels that are expressed at the cell surface. The trafficking of channels
is controlled by numerous processes, including co-assembly with ancillary calcium channel subunits, ubiquitin ligases, and
interactions with other membrane proteins such as G protein coupled receptors. Here we provide an overview about the current
state of knowledge of calcium channel trafficking to the cell membrane, and of the mechanisms regulating the stability and
internalization of this important ion channel family. 相似文献
136.
Although all nucleated cells within a multicellular organism contain a complete copy of the genome, cell identity relies on
the expression of a specific subset of genes. Therefore, when cells divide they must not only copy their genome to their daughters,
but also ensure that the pattern of gene expression present before division is restored. While the carrier of this epigenetic
memory has been a topic of much research and debate, post-translational modifications of histone proteins have emerged in
the vanguard of candidates. In this paper we examine the mechanisms by which histone post-translational modifications are
propagated through DNA replication and cell division, and we critically examine the evidence that they can also act as vectors
of epigenetic memory. Finally, we consider ways in which epigenetic memory might be disrupted by interfering with the mechanisms
of DNA replication. 相似文献
137.
Valiokas R 《Cellular and molecular life sciences : CMLS》2012,69(3):347-356
The actual progress towards biological chip devices consisting of nanostructured functional entities is summarized. The practical
aspects of molecular nanobiochips are discussed, including the main surface chemistry platforms, as well as conventional and
unconventional fabrication tools. Several successful biological demonstrations of the first generation of nanobiochip devices
(mainly, different nanoarrays) are highlighted with the aim of revealing the potential of this technology in life sciences,
medicine, and related areas. 相似文献
138.
Toll-like receptors (TLRs) are a class of pattern recognition receptors sensing microbial components and triggering an immune
response against pathogens. In addition to their role in anti-infection immunity, increasing evidence indicates that engagement
of TLRs can promote cancer cell survival and proliferation, induce tumor immune evasion, and enhance tumor metastasis and
chemoresistance. Recent studies have demonstrated that endogenous molecules or damage-associated molecular patterns released
from damaged/necrotic tissues are capable of activating TLRs and that the endogenous ligands-mediated TLR signaling is implicated
in the tumor development and affects the therapeutic efficacy of tumors. Since both exogenous and endogenous TLR ligands can
initiate TLR signaling, which is the most valuable player in tumor development becomes an interesting question. Here, we summarize
the effect of TLR signaling on the development and progression of tumors, and discuss the role of exogenous and endogenous
TLR ligands in the tumorigenesis. 相似文献
139.
Machnicka B Grochowalska R Bogusławska DM Sikorski AF Lecomte MC 《Cellular and molecular life sciences : CMLS》2012,69(2):191-201
This review focuses on the recent advances in functions of spectrins in non-erythroid cells. We discuss new data concerning
the commonly known role of the spectrin-based skeleton in control of membrane organization, stability and shape, and tethering
protein mosaics to the cellular motors and to all major filament systems. Particular effort has been undertaken to highlight
recent advances linking spectrin to cell signaling phenomena and its participation in signal transduction pathways in many
cell types. 相似文献
140.
Xue B Mizianty MJ Kurgan L Uversky VN 《Cellular and molecular life sciences : CMLS》2012,69(8):1211-1259
Many proteins and protein regions are disordered in their native, biologically active states. These proteins/regions are abundant
in different organisms and carry out important biological functions that complement the functional repertoire of ordered proteins.
Viruses, with their highly compact genomes, small proteomes, and high adaptability for fast change in their biological and
physical environment utilize many of the advantages of intrinsic disorder. In fact, viral proteins are generally rich in intrinsic
disorder, and intrinsically disordered regions are commonly used by viruses to invade the host organisms, to hijack various
host systems, and to help viruses in accommodation to their hostile habitats and to manage their economic usage of genetic
material. In this review, we focus on the structural peculiarities of HIV-1 proteins, on the abundance of intrinsic disorder
in viral proteins, and on the role of intrinsic disorder in their functions. 相似文献