全文获取类型
收费全文 | 8765篇 |
免费 | 666篇 |
国内免费 | 453篇 |
出版年
2023年 | 72篇 |
2022年 | 72篇 |
2021年 | 285篇 |
2020年 | 231篇 |
2019年 | 265篇 |
2018年 | 282篇 |
2017年 | 232篇 |
2016年 | 320篇 |
2015年 | 461篇 |
2014年 | 581篇 |
2013年 | 640篇 |
2012年 | 741篇 |
2011年 | 705篇 |
2010年 | 415篇 |
2009年 | 371篇 |
2008年 | 424篇 |
2007年 | 417篇 |
2006年 | 367篇 |
2005年 | 359篇 |
2004年 | 292篇 |
2003年 | 299篇 |
2002年 | 241篇 |
2001年 | 194篇 |
2000年 | 193篇 |
1999年 | 161篇 |
1998年 | 107篇 |
1997年 | 98篇 |
1996年 | 102篇 |
1995年 | 101篇 |
1994年 | 79篇 |
1993年 | 78篇 |
1992年 | 127篇 |
1991年 | 101篇 |
1990年 | 66篇 |
1989年 | 71篇 |
1988年 | 62篇 |
1987年 | 44篇 |
1986年 | 39篇 |
1985年 | 48篇 |
1984年 | 27篇 |
1983年 | 21篇 |
1982年 | 16篇 |
1981年 | 7篇 |
1979年 | 9篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1971年 | 7篇 |
1970年 | 7篇 |
1968年 | 5篇 |
1966年 | 7篇 |
排序方式: 共有9884条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
William J. Sames Terry A. Klein Heung Chul Kim Sung Tae Chong In Yong Lee Se Hun Gu Yon Mi Park Ji Hye Jeong Jin‐Won Song 《Journal of vector ecology》2009,34(2):225-231
The Twin Bridges Training Area (TBTA) in the Republic of Korea consists of dirt roads, barren training areas, and forested hillsides adjacent to linear and broad expanses of tall grasses, herbaceous, and scrub vegetation. Of the six species of small mammals, the striped field mouse, Apodemus agrarius, was the most frequently captured (96.1%). Apodemus agrarius capture rates varied from 17.7 to 33.2% during three trapping periods. Gravid females were observed during November‐December 2006 (8.4%) and March 2007 (5.1%). In 2005, the overall seroprevalence of Hantaan virus (HTNV) was high (34.4%) and lower during surveys in 2006 (14.2%) and 2007 (13.8%). Seroprevalence was directly correlated with weight increase of A. agrarius. 相似文献
9.
Kuwahara Michio; Ishibashi Kenichi; Gu Yong; Terada Yoshio; Kohara Yuji; Marumo Fumiaki; Sasaki Sei 《American journal of physiology. Cell physiology》1998,275(6):C1459
A genome project focusingon the nematode Caenorhabditis elegans has demonstrated thepresence of eight cDNAs belonging to the major intrinsic proteinsuperfamily. We functionally characterized one of these cDNAs namedC01G6.1. Injection of C01G6.1 cRNA increased the osmotic waterpermeability (Pf) of Xenopusoocytes 11-fold and the urea permeability 4.5-fold but failed toincrease the glycerol permeability. It has been speculated that the MIPfamily may be separated into two large subfamilies based on thepresence or absence of two segments of extra amino acid residues (~15amino acids) at the second and third extracellular loops. BecauseC01G6.1 (designated AQP-CE1), AQP3, and glycerol facilitator (GlpF) all have these two segments, we replaced the segments of AQP-CE1 with thoseof AQP3 and GlpF to identify their roles. The functional characteristics of these mutants were principally similar to that ofwild-type AQP-CE1, although the values of Pf andurea permeability were decreased by 39-74% and 28-65%,respectively. These results suggest that the two segments of extraamino acid residues may not contribute to channel selectivity orformation of the route for small solutes. 相似文献
10.
Brian E. Roe Michael R. Tilley Howard H. Gu David Q. Beversdorf Wolfgang Sadee Timothy C. Haab Audrey C. Papp 《PloS one》2009,4(8)
With recent advances in understanding of the neuroscience of risk taking, attention is now turning to genetic factors that may contribute to individual heterogeneity in risk attitudes. In this paper we test for genetic associations with risk attitude measures derived from both the psychology and economics literature. To develop a long-term prospective study, we first evaluate both types of risk attitudes and find that the economic and psychological measures are poorly correlated, suggesting that different genetic factors may underlie human response to risk faced in different behavioral domains. We then examine polymorphisms in a spectrum of candidate genes that affect neurotransmitter systems influencing dopamine regulation or are thought to be associated with risk attitudes or impulsive disorders. Analysis of the genotyping data identified two single nucleotide polymorphisms (SNPs) in the gene encoding the alpha 4 nicotine receptor (CHRNA4, rs4603829 and rs4522666) that are significantly associated with harm avoidance, a risk attitude measurement drawn from the psychology literature. Novelty seeking, another risk attitude measure from the psychology literature, is associated with several COMT (catechol-O-methyl transferase) SNPs while economic risk attitude measures are associated with several VMAT2 (vesicular monoamine transporter) SNPs, but the significance of these associations did not withstand statistical adjustment for multiple testing and requires larger cohorts. These exploratory results provide a starting point for understanding the genetic basis of risk attitudes by considering the range of methods available for measuring risk attitudes and by searching beyond the traditional direct focus on dopamine and serotonin receptor and transporter genes. 相似文献