全文获取类型
收费全文 | 1417篇 |
免费 | 7篇 |
国内免费 | 12篇 |
专业分类
系统科学 | 36篇 |
教育与普及 | 4篇 |
理论与方法论 | 27篇 |
现状及发展 | 191篇 |
研究方法 | 266篇 |
综合类 | 854篇 |
自然研究 | 58篇 |
出版年
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 22篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 24篇 |
2012年 | 113篇 |
2011年 | 209篇 |
2010年 | 39篇 |
2009年 | 6篇 |
2008年 | 114篇 |
2007年 | 112篇 |
2006年 | 120篇 |
2005年 | 119篇 |
2004年 | 109篇 |
2003年 | 104篇 |
2002年 | 123篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1996年 | 4篇 |
1994年 | 2篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 7篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 6篇 |
1973年 | 8篇 |
1971年 | 4篇 |
1970年 | 5篇 |
1968年 | 6篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有1436条查询结果,搜索用时 15 毫秒
11.
12.
A microRNA component of the p53 tumour suppressor network 总被引:5,自引:0,他引:5
13.
讨论了同震库仑应力改变的基本含义,以及基于静应力位错理论求解同震库仑应力改变的边界元方法,对与发震断层相互平行和相互垂直两种典型构造模式下,断层相互作用产生的同震库仑应力改变进行了数值模拟研究,分别获取了相应条件下的同震库仑应力改变空间分布图像.结果表明:不同构造模式的断层相互作用,其产生的同震库仑应力改变分布图像存在较大差异,在分析和评价断层相互作用产生的同震库仑应力改变,及其对活动断层地震危险性的影响时,应该充分考虑待评价断层与发震断层之间的空间几何关系、断层的性质和产状等特定的构造条件. 相似文献
14.
Zheng Liu Yuri G. Andreev A. Robert Armstrong Sergio Brutti Yu Ren Peter G. Bruce 《自然科学进展(英文版)》2013,23(3):235-244
Reducing the dimensions of electrode materials from the micron to the nanoscale can have a profound influence on their properties and hence on the performance of electrochemical devices,e.g.Li-ion batteries,that employ such electrodes.TiO2(B) has received growing interest as a possible anode for Li-ion batteries in recent years.It offers the possibility of higher energy storage compared with the commercialized Li4Ti5O12.Bulk,nanowire,nanotube,and nanoparticle morphologies have been prepared and studied.However,to date these materials have not be compared in one article.In the current review we first summarize the different synthesis methods for the preparation of nanostructured TiO2(B);then present the effects of size and shape on the electrochemical properties.Finally TiO2(B) with nanometer dimensions exhibit a higher capacity to store Li,regardless of rate,due to structural distortions inherent at the nanoscale. 相似文献
15.
16.
Is there a decline in marine phytoplankton? 总被引:1,自引:0,他引:1
McQuatters-Gollop A Reid PC Edwards M Burkill PH Castellani C Batten S Gieskes W Beare D Bidigare RR Head E Johnson R Kahru M Koslow JA Pena A 《Nature》2011,472(7342):E6-7; discussion E8-9
17.
Accurate translation of genetic information into protein sequence depends on complete messenger RNA molecules. Truncated mRNAs cause synthesis of defective proteins, and arrest ribosomes at the end of their incomplete message. In bacteria, a hybrid RNA molecule that combines the functions of both transfer and messenger RNAs (called tmRNA) rescues stalled ribosomes, and targets aberrant, partially synthesized, proteins for proteolytic degradation. Here we report the 3.2-A-resolution structure of the tRNA-like domain of tmRNA (tmRNA(Delta)) in complex with small protein B (SmpB), a protein essential for biological functions of tmRNA. We find that the flexible RNA molecule adopts an open L-shaped conformation and SmpB binds to its elbow region, stabilizing the single-stranded D-loop in an extended conformation. The most striking feature of the structure of tmRNA(Delta) is a 90 degrees rotation of the TPsiC-arm around the helical axis. Owing to this unusual conformation, the SmpB-tmRNA(Delta) complex positioned into the A-site of the ribosome orients SmpB towards the small ribosomal subunit, and directs tmRNA towards the elongation-factor binding region of the ribosome. On the basis of this structure, we propose a model for the binding of tmRNA on the ribosome. 相似文献
18.
19.
Loss of GLIS2 causes nephronophthisis in humans and mice by increased apoptosis and fibrosis 总被引:4,自引:0,他引:4
20.
Dina C Meyre D Gallina S Durand E Körner A Jacobson P Carlsson LM Kiess W Vatin V Lecoeur C Delplanque J Vaillant E Pattou F Ruiz J Weill J Levy-Marchal C Horber F Potoczna N Hercberg S Le Stunff C Bougnères P Kovacs P Marre M Balkau B Cauchi S Chèvre JC Froguel P 《Nature genetics》2007,39(6):724-726
We identified a set of SNPs in the first intron of the FTO (fat mass and obesity associated) gene on chromosome 16q12.2 that is consistently strongly associated with early-onset and severe obesity in both adults and children of European ancestry with an experiment-wise P value of 1.67 x 10(-26) in 2,900 affected individuals and 5,100 controls. The at-risk haplotype yields a proportion of attributable risk of 22% for common obesity. We conclude that FTO contributes to human obesity and hence may be a target for subsequent functional analyses. 相似文献