全文获取类型
收费全文 | 21370篇 |
免费 | 1625篇 |
国内免费 | 1546篇 |
专业分类
24541篇 |
出版年
2024年 | 57篇 |
2023年 | 250篇 |
2022年 | 659篇 |
2021年 | 1164篇 |
2020年 | 766篇 |
2019年 | 932篇 |
2018年 | 905篇 |
2017年 | 670篇 |
2016年 | 944篇 |
2015年 | 1294篇 |
2014年 | 1562篇 |
2013年 | 1711篇 |
2012年 | 1883篇 |
2011年 | 1752篇 |
2010年 | 1080篇 |
2009年 | 984篇 |
2008年 | 1128篇 |
2007年 | 999篇 |
2006年 | 855篇 |
2005年 | 736篇 |
2004年 | 566篇 |
2003年 | 545篇 |
2002年 | 444篇 |
2001年 | 322篇 |
2000年 | 325篇 |
1999年 | 325篇 |
1998年 | 189篇 |
1997年 | 170篇 |
1996年 | 181篇 |
1995年 | 175篇 |
1994年 | 158篇 |
1993年 | 116篇 |
1992年 | 158篇 |
1991年 | 113篇 |
1990年 | 110篇 |
1989年 | 77篇 |
1988年 | 54篇 |
1987年 | 46篇 |
1986年 | 35篇 |
1985年 | 35篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 16篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1966年 | 1篇 |
1950年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Androgen receptor binding to an androgen‐responsive element in the promoter of the Srsf4 gene inhibits its expression in mouse Sertoli cells 下载免费PDF全文
102.
Biotype status and distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) in Shandong province of China based on mitochondrial DNA markers 总被引:5,自引:0,他引:5
Chu D Jiang T Liu GX Jiang DF Tao YL Fan ZX Zhou HX Bi YP 《Environmental entomology》2007,36(5):1290-1295
Bemisia tabaci has caused significant crop losses in China during the last decade. Recent research has shown that two potentially invasive variants, biotypes B and Q, have been found in several regions of China. Our objective was to determine the biotype status and the distribution of B. tabaci in Shandong province, an important agricultural region of China. Based on mitochondrial DNA markers, both biotypes B and Q were detected, with B being the predominant biotype. The results indicate that the more recently introduced biotype Q has not only been located in China but also has established and spread in some regions. 相似文献
103.
Qin Zhou Fan Zhao Ze-ping Lv Chen-guang Zheng Wei-dong Zheng Liang Sun Na-na Wang Shenghang Pang Fabiana Michelsen de Andrade Mian Fu Xiang-hua He Juan Hui Wen-yu Jiang Chu-yu Yang Xiao-hong Shi Xiao-quan Zhu Guo-fang Pang Yi-ge Yang Hai-qun Xie Wan-dong Zhang Cai-you Hu Ze Yang 《PloS one》2014,9(1)
Background
Previous association studies examining the relationship between the APOC1 polymorphism and susceptibility to Alzheimer’s disease (AD) have shown conflicting results, and it is not clear if an APOC1 variant acts as a genetic risk factor in AD etiology across multiple populations.Methods
To confirm the risk association between APOC1 and AD, we designed a case-control study and also performed a meta-analysis of previously published studies.Results
Seventy-nine patients with AD and one hundred fifty-six unrelated controls were included in case-control study. No association was found between the variation of APOC1 and AD in stage 1 of our study. However, our meta-analysis pooled a total of 2092 AD patients and 2685 controls. The APOC1 rs11568822 polymorphism was associated with increased AD risk in Caucasians, Asians and Caribbean Hispanics, but not in African Americans. APOE ε4 carriers harboring the APOC1 insertion allele, were more prevalent in AD patients than controls (χ2 = 119.46, OR = 2.79, 95% CI = 2.31–3.36, P<0.01).Conclusions
The APOC1 insertion allele, in combination with APOE ε4, likely serves as a potential risk factor for developing AD. 相似文献104.
105.
106.
107.
108.
109.
Cardiac mitochondrial ATP-sensitive potassium channel is activated by nitric oxide in vitro 总被引:1,自引:0,他引:1
Previous observations on the activation of the mitochondrial ATP-sensitive potassium channel (mitoK(ATP)) by nitric oxide (NO) in myocardial preconditioning were based on indirect evidence. In this study, we have investigated the direct effect of NO on the rat cardiac mitoK(ATP) after reconstitution of the inner mitochondrial membranes into lipid bilayers. We found that the mitoK(ATP) was activated by exogenous NO donor S-nitroso-N-acetyl penicillamine or PAPA NONOate. This activation was inhibited by mitoK(ATP) blockers 5-hydroxydecanoate or glibenclamide. Our observations confirm that NO can directly activate the cardiac mitoK(ATP), which may underlie its contribution to myocardial preconditioning. 相似文献
110.
Xiaomeng Yang Shuya Li Xingquan Zhao Liping Liu Yong Jiang Zixiao Li Yilong Wang Yongjun Wang 《BMC neurology》2017,17(1):207