全文获取类型
收费全文 | 14589篇 |
免费 | 1416篇 |
国内免费 | 5篇 |
专业分类
16010篇 |
出版年
2023年 | 53篇 |
2022年 | 194篇 |
2021年 | 350篇 |
2020年 | 192篇 |
2019年 | 243篇 |
2018年 | 306篇 |
2017年 | 252篇 |
2016年 | 437篇 |
2015年 | 766篇 |
2014年 | 783篇 |
2013年 | 888篇 |
2012年 | 1187篇 |
2011年 | 1146篇 |
2010年 | 705篇 |
2009年 | 613篇 |
2008年 | 866篇 |
2007年 | 848篇 |
2006年 | 827篇 |
2005年 | 741篇 |
2004年 | 698篇 |
2003年 | 682篇 |
2002年 | 592篇 |
2001年 | 114篇 |
2000年 | 69篇 |
1999年 | 134篇 |
1998年 | 201篇 |
1997年 | 114篇 |
1996年 | 117篇 |
1995年 | 108篇 |
1994年 | 96篇 |
1993年 | 113篇 |
1992年 | 93篇 |
1991年 | 71篇 |
1990年 | 76篇 |
1989年 | 62篇 |
1988年 | 72篇 |
1987年 | 53篇 |
1986年 | 50篇 |
1985年 | 54篇 |
1984年 | 64篇 |
1983年 | 74篇 |
1982年 | 66篇 |
1981年 | 61篇 |
1980年 | 64篇 |
1979年 | 42篇 |
1978年 | 43篇 |
1977年 | 41篇 |
1976年 | 43篇 |
1975年 | 40篇 |
1974年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Do CB Tung JY Dorfman E Kiefer AK Drabant EM Francke U Mountain JL Goldman SM Tanner CM Langston JW Wojcicki A Eriksson N 《PLoS genetics》2011,7(6):e1002141
Although the causes of Parkinson's disease (PD) are thought to be primarily environmental, recent studies suggest that a number of genes influence susceptibility. Using targeted case recruitment and online survey instruments, we conducted the largest case-control genome-wide association study (GWAS) of PD based on a single collection of individuals to date (3,426 cases and 29,624 controls). We discovered two novel, genome-wide significant associations with PD-rs6812193 near SCARB2 (p = 7.6 × 10(-10), OR = 0.84) and rs11868035 near SREBF1/RAI1 (p = 5.6 × 10(-8), OR = 0.85)-both replicated in an independent cohort. We also replicated 20 previously discovered genetic associations (including LRRK2, GBA, SNCA, MAPT, GAK, and the HLA region), providing support for our novel study design. Relying on a recently proposed method based on genome-wide sharing estimates between distantly related individuals, we estimated the heritability of PD to be at least 0.27. Finally, using sparse regression techniques, we constructed predictive models that account for 6%-7% of the total variance in liability and that suggest the presence of true associations just beyond genome-wide significance, as confirmed through both internal and external cross-validation. These results indicate a substantial, but by no means total, contribution of genetics underlying susceptibility to both early-onset and late-onset PD, suggesting that, despite the novel associations discovered here and elsewhere, the majority of the genetic component for Parkinson's disease remains to be discovered. 相似文献
992.
993.
994.
995.
Elizabeth Howard Vitaly Citovsky 《BioEssays : news and reviews in molecular, cellular and developmental biology》1990,12(3):103-108
Single-stranded DNA-protein complex (T-complex) is proposed to mediate T-DNA transfer from Agrobacterium to plant cells. A novel model for transfer is presented which incorporates features of both bacterial conjugation and viral infection. Specific protein components of the T-complex, its ultrastructure and possible functions in the plant cell are discussed. 相似文献
996.
997.
998.
The Flora of the Perivaginal Area: The Normal Flora and the Effect of a Deodorant Spray 总被引:1,自引:1,他引:0
Susan Crowley Catherine T. Murphy Pamela M. White W. C. Noble Elizabeth R. M. Rowell D. Bluett 《Journal of applied microbiology》1974,37(3):385-392
S ummary . The microbial flora of the thigh adjacent to the vaginal labia and of the mucosal surface of the labia has been examined quantitatively and qualitatively in students from Colleges of Education and a University, and in persons attending a Consultant Gynaecologist for non-suppurative conditions. In the 2 student populations, members of the Micrococcaceae and diphtheroids were the most common organisms but all populations yielded many organisms of gut origin. Differences between the populations may relate to social and hygienic conditions and should make us wary of direct comparisons with other, different populations. The effect of intimate hygiene deodorants containing 0.01% or 0.02% of chlorhexidine was compared with a base spray containing no antibacterial agent. No significant effect of these sprays on the microbial flora could be demonstrated. 相似文献
999.
1000.