全文获取类型
收费全文 | 1036篇 |
免费 | 0篇 |
专业分类
系统科学 | 15篇 |
教育与普及 | 1篇 |
理论与方法论 | 18篇 |
现状及发展 | 372篇 |
研究方法 | 169篇 |
综合类 | 455篇 |
自然研究 | 6篇 |
出版年
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2014年 | 11篇 |
2013年 | 11篇 |
2012年 | 58篇 |
2011年 | 73篇 |
2010年 | 26篇 |
2009年 | 6篇 |
2008年 | 38篇 |
2007年 | 53篇 |
2006年 | 54篇 |
2005年 | 50篇 |
2004年 | 29篇 |
2003年 | 30篇 |
2002年 | 41篇 |
2001年 | 33篇 |
2000年 | 42篇 |
1999年 | 34篇 |
1992年 | 31篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 15篇 |
1985年 | 23篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 20篇 |
1978年 | 14篇 |
1977年 | 12篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1974年 | 11篇 |
1973年 | 12篇 |
1972年 | 14篇 |
1971年 | 15篇 |
1970年 | 14篇 |
1969年 | 12篇 |
1968年 | 9篇 |
1967年 | 11篇 |
1966年 | 8篇 |
1964年 | 6篇 |
1960年 | 5篇 |
1957年 | 5篇 |
1956年 | 6篇 |
排序方式: 共有1036条查询结果,搜索用时 15 毫秒
41.
42.
43.
Yvonne G. J. van Helden Roger W. L. Godschalk Hans J. M. Swarts Peter C. H. Hollman Frederik J. van Schooten Jaap Keijer 《Cellular and molecular life sciences : CMLS》2011,68(3):489-504
Molecular mechanisms triggered by high dietary beta-carotene (BC) intake in lung are largely unknown. We performed microarray
gene expression analysis on lung tissue of BC supplemented beta-carotene 15,15′-monooxygenase 1 knockout (Bcmo1
−/−) mice, which are—like humans—able to accumulate BC. Our main observation was that the genes were regulated in an opposite direction in male and female Bcmo1
−/− mice by BC. The steroid biosynthetic pathway was overrepresented in BC-supplemented male Bcmo1
−/− mice. Testosterone levels were higher after BC supplementation only in Bcmo1
−/− mice, which had, unlike wild-type (Bcmo1
+/+) mice, large variations. We hypothesize that BC possibly affects hormone synthesis or metabolism. Since sex hormones influence
lung cancer risk, these data might contribute to an explanation for the previously found increased lung cancer risk after
BC supplementation (ATBC and CARET studies). Moreover, effects of BC may depend on the presence of frequent human BCMO1 polymorphisms, since these effects were not found in wild-type mice. 相似文献
44.
Matmati M Jacques P Maelfait J Verheugen E Kool M Sze M Geboes L Louagie E Mc Guire C Vereecke L Chu Y Boon L Staelens S Matthys P Lambrecht BN Schmidt-Supprian M Pasparakis M Elewaut D Beyaert R van Loo G 《Nature genetics》2011,43(9):908-912
A20 (TNFAIP3) is a protein that is involved in the negative feedback regulation of NF-κB signaling in response to specific proinflammatory stimuli in different cell types and has been suggested as a susceptibility gene for rheumatoid arthritis. To define the contribution of A20 to rheumatoid arthritis pathology, we generated myeloid-specific A20-deficient mice and show that specific ablation of Tnfaip3 in myeloid cells results in spontaneous development of a severe destructive polyarthritis with many features of rheumatoid arthritis. Myeloid-A20-deficient mice have high levels of inflammatory cytokines in their serum, consistent with a sustained NF-κB activation and higher TNF production by macrophages. Destructive polyarthritis in myeloid A20 knockout mice was TLR4-MyD88 and IL-6 dependent but was TNF independent. Myeloid A20 deficiency also promoted osteoclastogenesis in mice. Together, these observations indicate a critical and cell-specific function for A20 in the etiology of rheumatoid arthritis, supporting the idea of developing A20 modulatory drugs as cell-targeted therapies. 相似文献
45.
Dense genotyping identifies and localizes multiple common and rare variant association signals in celiac disease 总被引:1,自引:0,他引:1
Trynka G Hunt KA Bockett NA Romanos J Mistry V Szperl A Bakker SF Bardella MT Bhaw-Rosun L Castillejo G de la Concha EG de Almeida RC Dias KR van Diemen CC Dubois PC Duerr RH Edkins S Franke L Fransen K Gutierrez J Heap GA Hrdlickova B Hunt S Izurieta LP Izzo V Joosten LA Langford C Mazzilli MC Mein CA Midah V Mitrovic M Mora B Morelli M Nutland S Núñez C Onengut-Gumuscu S Pearce K Platteel M Polanco I Potter S Ribes-Koninckx C Ricaño-Ponce I Rich SS Rybak A Santiago JL Senapati S Sood A 《Nature genetics》2011,43(12):1193-1201
Using variants from the 1000 Genomes Project pilot European CEU dataset and data from additional resequencing studies, we densely genotyped 183 non-HLA risk loci previously associated with immune-mediated diseases in 12,041 individuals with celiac disease (cases) and 12,228 controls. We identified 13 new celiac disease risk loci reaching genome-wide significance, bringing the number of known loci (including the HLA locus) to 40. We found multiple independent association signals at over one-third of these loci, a finding that is attributable to a combination of common, low-frequency and rare genetic variants. Compared to previously available data such as those from HapMap3, our dense genotyping in a large sample collection provided a higher resolution of the pattern of linkage disequilibrium and suggested localization of many signals to finer scale regions. In particular, 29 of the 54 fine-mapped signals seemed to be localized to single genes and, in some instances, to gene regulatory elements. Altogether, we define the complex genetic architecture of the risk regions of and refine the risk signals for celiac disease, providing the next step toward uncovering the causal mechanisms of the disease. 相似文献
46.
Extensive and coordinated transcription of noncoding RNAs within cell-cycle promoters 总被引:5,自引:0,他引:5
47.
Chasman DI Schürks M Anttila V de Vries B Schminke U Launer LJ Terwindt GM van den Maagdenberg AM Fendrich K Völzke H Ernst F Griffiths LR Buring JE Kallela M Freilinger T Kubisch C Ridker PM Palotie A Ferrari MD Hoffmann W Zee RY Kurth T 《Nature genetics》2011,43(7):695-698
Migraine is a common, heterogeneous and heritable neurological disorder. Its pathophysiology is incompletely understood, and its genetic influences at the population level are unknown. In a population-based genome-wide analysis including 5,122 migraineurs and 18,108 non-migraineurs, rs2651899 (1p36.32, PRDM16), rs10166942 (2q37.1, TRPM8) and rs11172113 (12q13.3, LRP1) were among the top seven associations (P < 5 × 10(-6)) with migraine. These SNPs were significant in a meta-analysis among three replication cohorts and met genome-wide significance in a meta-analysis combining the discovery and replication cohorts (rs2651899, odds ratio (OR) = 1.11, P = 3.8 × 10(-9); rs10166942, OR = 0.85, P = 5.5 × 10(-12); and rs11172113, OR = 0.90, P = 4.3 × 10(-9)). The associations at rs2651899 and rs10166942 were specific for migraine compared with non-migraine headache. None of the three SNP associations was preferential for migraine with aura or without aura, nor were any associations specific for migraine features. TRPM8 has been the focus of neuropathic pain models, whereas LRP1 modulates neuronal glutamate signaling, plausibly linking both genes to migraine pathophysiology. 相似文献
48.
Crossan GP van der Weyden L Rosado IV Langevin F Gaillard PH McIntyre RE;Sanger Mouse Genetics Project Gallagher F Kettunen MI Lewis DY Brindle K Arends MJ Adams DJ Patel KJ 《Nature genetics》2011,43(2):147-152
The evolutionarily conserved SLX4 protein, a key regulator of nucleases, is critical for DNA damage response. SLX4 nuclease complexes mediate repair during replication and can also resolve Holliday junctions formed during homologous recombination. Here we describe the phenotype of the Btbd12 knockout mouse, the mouse ortholog of SLX4, which recapitulates many key features of the human genetic illness Fanconi anemia. Btbd12-deficient animals are born at sub-Mendelian ratios, have greatly reduced fertility, are developmentally compromised and are prone to blood cytopenias. Btbd12(-/-) cells prematurely senesce, spontaneously accumulate damaged chromosomes and are particularly sensitive to DNA crosslinking agents. Genetic complementation reveals a crucial requirement for Btbd12 (also known as Slx4) to interact with the structure-specific endonuclease Xpf-Ercc1 to promote crosslink repair. The Btbd12 knockout mouse therefore establishes a disease model for Fanconi anemia and genetically links a regulator of nuclease incision complexes to the Fanconi anemia DNA crosslink repair pathway. 相似文献
49.
This article discusses the quest for the mechanical advantage of the wedge in the eighteenth century. As a case study, the wedge enlightens our understanding of eighteenth-century mechanics in general and the controversy over “force” or vis viva in particular. In this article, I show that the two different approaches to mechanics, the one that favoured force in terms of velocities and the one that primarily used displacements—known as the ‘Newtonian’ and ‘Leibnizian’ methods, respectively—were not at all on par in their ability to solve the problem of the wedge. In general, only those who used the Leibnizian concept of force or some related notion were able to get to the conventional results. This article thus rebuts the received view that the vis viva controversy was merely a semantic one. Instead, it shows that different understandings of “force” led to real and pragmatic differences in eighteenth-century mechanics. 相似文献
50.
G. M. C. Janssen P. Schwertman T. A. T. Wanga R. S. Jahangir Tafrechi P. J. A. van den Broek A. K. Raap 《Cellular and molecular life sciences : CMLS》2009,66(4):721-730
Cytoplasmic translation is under sophisticated control but how cells adapt its rate to constitutive loss of mitochondrial
oxidative phosphorylation is unknown. Here we show that translation is repressed in cells with the pathogenic A3243G mtDNA
mutation or in mtDNA-less ρ0 cells by at least two distinct pathways, one transiently targeting elongation factor eEF-2 and the other initiation factor
eIF-2α constitutively. Under conditions of exponential cell growth and mammalian target of rapamycin (mTOR) activation, eEF-2
becomes transiently phosphorylated by an AMP-activated protein kinase (AMPK)-dependent pathway, especially high in mutant
cells. Independent of AMPK and mTOR, eIF-2α is constitutively phosphorylated in mutant cells, likely a signature of endoplasmic
reticulum (ER)-stress response induced by the loss of oxidative phosphorylation. While the AMPK/eEF-2K/eEF-2 pathway appears
to function in adaptation to physiological fluctuations in ATP levels in the mutant cells, the ER stress signified by constitutive
protein synthesis inhibition through eIF-2α-mediated repression of translation initiation may have pathobiochemical consequences.
Received 29 October 2008; received after revision 11 December 2008; accepted 16 December 2008 相似文献