全文获取类型
收费全文 | 2424篇 |
免费 | 193篇 |
国内免费 | 2篇 |
专业分类
2619篇 |
出版年
2023年 | 20篇 |
2022年 | 39篇 |
2021年 | 95篇 |
2020年 | 44篇 |
2019年 | 68篇 |
2018年 | 67篇 |
2017年 | 58篇 |
2016年 | 96篇 |
2015年 | 151篇 |
2014年 | 150篇 |
2013年 | 182篇 |
2012年 | 213篇 |
2011年 | 185篇 |
2010年 | 120篇 |
2009年 | 96篇 |
2008年 | 132篇 |
2007年 | 119篇 |
2006年 | 118篇 |
2005年 | 91篇 |
2004年 | 95篇 |
2003年 | 73篇 |
2002年 | 74篇 |
2001年 | 29篇 |
2000年 | 25篇 |
1999年 | 24篇 |
1998年 | 23篇 |
1997年 | 15篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 18篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1979年 | 5篇 |
1977年 | 6篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1972年 | 5篇 |
1971年 | 6篇 |
1970年 | 4篇 |
1969年 | 7篇 |
排序方式: 共有2619条查询结果,搜索用时 15 毫秒
61.
62.
63.
John M. Edwards Jed Long Cornelia H. de Moor Jonas Emsley Mark S. Searle 《Nucleic acids research》2013,41(14):7153-7166
The CUG-BP, Elav-like family (CELF) of RNA-binding proteins control gene expression at a number of different levels by regulating pre-mRNA splicing, deadenylation and mRNA stability. We present structural insights into the binding selectivity of CELF member 1 (CELF1) for GU-rich mRNA target sequences of the general form 5′-UGUNxUGUNyUGU and identify a high affinity interaction (Kd ∼ 100 nM for x = 2 and y = 4) with simultaneous binding of all three RNA recognition motifs within a single 15-nt binding element. RNA substrates spin-labelled at either the 3′ or 5′ terminus result in differential nuclear magnetic resonance paramagnetic relaxation enhancement effects, which are consistent with a non-sequential 2-1-3 arrangement of the three RNA recognition motifs on UGU sites in a 5′ to 3′ orientation along the RNA target. We further demonstrate that CELF1 binds to dispersed single-stranded UGU sites at the base of an RNA hairpin providing a structural rationale for recognition of CUG expansion repeats and splice site junctions in the regulation of alternative splicing. 相似文献
64.
65.
66.
67.
68.
Alfhild Grönbladh Jenny Johansson Mark M. Kushnir Jonas Bergquist Mathias Hallberg 《Steroids》2013,78(12-13):1192-1199
Growth hormone (GH) and anabolic androgenic steroids (AAS) are commonly used in sports communities. Several studies have suggested an association between GH and AAS. We have investigated the impact of GH in rats treated with nandrolone decanoate (ND). Male Wistar rats received ND (15 mg/kg) every third day during three weeks and were subsequently treated with recombinant human GH (1.0 IU/kg) for ten consecutive days. Plasma samples were collected and peripheral organs (i.e. heart, liver, testis and thymus) were dissected and weighed. Concentration of thirteen endogenous steroids was measured in the rat plasma samples using high specificity LC–MS/MS methods. Seven steroids were detected and quantified, and concentrations of estrone, testosterone, and androstenedione were significantly different among the groups, while concentrations of pregnenolone, DHEA, 17-hydroxyprogesterone and corticosterone were not altered. Administration of rhGH alone altered the plasma steroid distribution, and the results demonstrated significantly increased concentrations of plasma estrone as well as decreased concentrations of testosterone and androstenedione in the ND-treated rats. Administration of rhGH to ND-pretreated rats did not reverse the alteration of the steroid distribution induced by ND. Administration of ND decreased the weight of the thymus, and addition of rhGH did not reverse this reduction. However, rhGH administration induced an enlargement of thymus. Taken together, the plasma steroid profile differed in the four groups, i.e. control, AAS, rhGH and the combination of AAS and rhGH treatment. 相似文献
69.
Tao Wang Zhen Lin Robert E. Day Bruce Gardiner Euphemie Landao‐Bassonga Jonas Rubenson Thomas B. Kirk David W. Smith David G. Lloyd Gerard Hardisty Allan Wang Qiujian Zheng Ming H. Zheng 《Biotechnology and bioengineering》2013,110(5):1495-1507
Identification of functional programmable mechanical stimulation (PMS) on tendon not only provides the insight of the tendon homeostasis under physical/pathological condition, but also guides a better engineering strategy for tendon regeneration. The aims of the study are to design a bioreactor system with PMS to mimic the in vivo loading conditions, and to define the impact of different cyclic tensile strain on tendon. Rabbit Achilles tendons were loaded in the bioreactor with/without cyclic tensile loading (0.25 Hz for 8 h/day, 0–9% for 6 days). Tendons without loading lost its structure integrity as evidenced by disorientated collagen fiber, increased type III collagen expression, and increased cell apoptosis. Tendons with 3% of cyclic tensile loading had moderate matrix deterioration and elevated expression levels of MMP‐1, 3, and 12, whilst exceeded loading regime of 9% caused massive rupture of collagen bundle. However, 6% of cyclic tensile strain was able to maintain the structural integrity and cellular function. Our data indicated that an optimal PMS is required to maintain the tendon homeostasis and there is only a narrow range of tensile strain that can induce the anabolic action. The clinical impact of this study is that optimized eccentric training program is needed to achieve maximum beneficial effects on chronic tendinopathy management. Biotechnol. Bioeng. 2013; 110: 1495–1507. © 2012 Wiley Periodicals, Inc. 相似文献
70.