全文获取类型
收费全文 | 3563篇 |
免费 | 172篇 |
专业分类
3735篇 |
出版年
2024年 | 22篇 |
2023年 | 23篇 |
2022年 | 43篇 |
2021年 | 77篇 |
2020年 | 39篇 |
2019年 | 39篇 |
2018年 | 51篇 |
2017年 | 51篇 |
2016年 | 99篇 |
2015年 | 172篇 |
2014年 | 173篇 |
2013年 | 205篇 |
2012年 | 262篇 |
2011年 | 232篇 |
2010年 | 158篇 |
2009年 | 148篇 |
2008年 | 206篇 |
2007年 | 182篇 |
2006年 | 173篇 |
2005年 | 190篇 |
2004年 | 185篇 |
2003年 | 177篇 |
2002年 | 153篇 |
2001年 | 61篇 |
2000年 | 50篇 |
1999年 | 42篇 |
1998年 | 40篇 |
1997年 | 34篇 |
1996年 | 17篇 |
1995年 | 24篇 |
1994年 | 29篇 |
1993年 | 20篇 |
1992年 | 25篇 |
1991年 | 26篇 |
1990年 | 23篇 |
1989年 | 17篇 |
1988年 | 26篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 13篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 11篇 |
1969年 | 6篇 |
排序方式: 共有3735条查询结果,搜索用时 0 毫秒
1.
A consensus linkage map of barley 总被引:5,自引:0,他引:5
Peter Langridge Angelo Karakousis Nick Collins Jodie Kretschmer Sue Manning 《Molecular breeding : new strategies in plant improvement》1995,1(4):389-395
A consensus linkage map of the barley genome was constructed. The map is based on six doubled haploid and one F2 population. The mapping data for three of the doubled haploid populations was obtained via the GrainGenes database. To allow merger of the maps, only RFLP markers that produce a single scorable band were included. Although this reduced the available markers by about half, the resultant map contains a total of 587 markers including 87 of known function. As expected, gene order was highly conserved between maps and all but two discrepancies were found in closely linked markers and are likely to result from the small population sizes used for some maps. The consensus map allows the rapid localisation of markers between published maps and should facilitate the selection of markers for high-density mapping in defined regions. 相似文献
2.
3.
4.
McKeown SC Hall A Giblin GM Lorthioir O Blunt R Lewell XQ Wilson RJ Brown SH Chowdhury A Coleman T Watson SP Chessell IP Pipe A Clayton N Goldsmith P 《Bioorganic & medicinal chemistry letters》2006,16(18):4767-4771
The discovery, synthesis and structure-activity relationship (SAR) of a novel series of EP1 receptor antagonists is described. Pyrazole acid 4, identified from a chemical array, had desirable physicochemical properties, an excellent in vitro microsomal inhibition and cytochrome P450 (CYP450) profile and good exposure levels in blood. This compound had an ED50 of 1.3 mg/kg in a rat pain model. A range of more potent analogues in the in vitro assay was identified using efficient array chemistry. These EP1 antagonists have potential as agents in the treatment of PGE2 mediated pain. 相似文献
5.
6.
7.
Serpell BG Scarvell JM Ball NB Smith PN 《Journal of strength and conditioning research / National Strength & Conditioning Association》2012,26(11):3160-3176
ABSTRACT: Serpell, BG, Scarvell, JM, Ball, NB, and Smith, PN. Mechanisms and risk factors for noncontact ACL injury in age mature athletes who engage in field or court sports: A summary of literature since 1980. J Strength Cond Res 26(11): 3160-3176, 2012-Epidemiological data show that in the last 10 years alone the incidence and rate of anterior cruciate ligament (ACL) injuries have not changed appreciably. Furthermore, many ACL injuries appear to be noncontact in nature and sustained while engaging in some field or court sport. Thus, the need to investigate novel methods and adopt training strategies to prevent ACL injuries is paramount. To do so, however, requires an understanding of the mechanisms and risk factors for the injury. The aim of this review was to investigate the mechanisms and risk factors for noncontact ACL injuries in age mature athletes who compete in field or court sports. A search of the entire MEDLINE database for biomedicine was performed, and an iterative reference check was also conducted. A total of 87 articles disclosed met the eligibility criteria. Articles were grouped into 'themes'; 'anatomical and biomechanical mechanisms and risk factors,' 'intrinsic mechanisms and risk factors,' and 'extrinsic mechanisms and risk factors.' In this review, it is concluded that there are still a number of risk factors and mechanisms for noncontact ACL injury that are not well understood. However, the importance of dynamic knee joint stability is highlighted. It is also suggested that novel methods for preventing ACL injury be investigated and developed. 相似文献
8.
Wu X Geraldes P Platt JL Cascalho M 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(2):934-941
Activation-induced cytidine deaminase (AID) is required for Ig class switch recombination, a process that introduces DNA double-strand breaks in B cells. We show in this study that AID associates with the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) promoting cell survival, presumably by resolving DNA double-strand breaks. Wild-type cells expressing AID mutants that fail to associate with DNA-PKcs or cells deficient in DNA-PKcs or 53BP1 expressing wild-type AID accumulate gammaH2AX foci, indicative of heightened DNA damage response. Thus, AID has two independent functions. AID catalyzes cytidine deamination that originates DNA double-strand breaks needed for recombination, and it promotes DNA damage response and cell survival. Our results thus resolve the paradox of how B cells undergoing DNA cytidine deamination and recombination exhibit heightened survival and suggest a mechanism for hyperIgM type II syndrome associated with AID mutants deficient in DNA-PKcs binding. 相似文献
9.
Background
Serotonin signaling influences social behavior in both human and nonhuman primates. In humans, variation upstream of the promoter region of the serotonin transporter gene (5-HTTLPR) has recently been shown to influence both behavioral measures of social anxiety and amygdala response to social threats. Here we show that length polymorphisms in 5-HTTLPR predict social reward and punishment in rhesus macaques, a species in which 5-HTTLPR variation is analogous to that of humans.Methodology/Principal Findings
In contrast to monkeys with two copies of the long allele (L/L), monkeys with one copy of the short allele of this gene (S/L) spent less time gazing at face than non-face images, less time looking in the eye region of faces, and had larger pupil diameters when gazing at photos of a high versus low status male macaques. Moreover, in a novel primed gambling task, presentation of photos of high status male macaques promoted risk-aversion in S/L monkeys but promoted risk-seeking in L/L monkeys. Finally, as measured by a “pay-per-view” task, S/L monkeys required juice payment to view photos of high status males, whereas L/L monkeys sacrificed fluid to see the same photos.Conclusions/Significance
These data indicate that genetic variation in serotonin function contributes to social reward and punishment in rhesus macaques, and thus shapes social behavior in humans and rhesus macaques alike. 相似文献10.