全文获取类型
收费全文 | 1061651篇 |
免费 | 112006篇 |
国内免费 | 389篇 |
出版年
2018年 | 10035篇 |
2017年 | 9627篇 |
2016年 | 13547篇 |
2015年 | 17473篇 |
2014年 | 20703篇 |
2013年 | 30300篇 |
2012年 | 33715篇 |
2011年 | 34603篇 |
2010年 | 23550篇 |
2009年 | 21868篇 |
2008年 | 30989篇 |
2007年 | 32094篇 |
2006年 | 30222篇 |
2005年 | 28923篇 |
2004年 | 28711篇 |
2003年 | 27660篇 |
2002年 | 26990篇 |
2001年 | 45275篇 |
2000年 | 44950篇 |
1999年 | 36487篇 |
1998年 | 13563篇 |
1997年 | 13885篇 |
1996年 | 13235篇 |
1995年 | 12231篇 |
1994年 | 12010篇 |
1993年 | 12024篇 |
1992年 | 30289篇 |
1991年 | 29539篇 |
1990年 | 28929篇 |
1989年 | 28442篇 |
1988年 | 26149篇 |
1987年 | 25061篇 |
1986年 | 23408篇 |
1985年 | 23435篇 |
1984年 | 19305篇 |
1983年 | 16922篇 |
1982年 | 12873篇 |
1981年 | 11623篇 |
1980年 | 11023篇 |
1979年 | 18351篇 |
1978年 | 14440篇 |
1977年 | 13021篇 |
1976年 | 12392篇 |
1975年 | 13739篇 |
1974年 | 14636篇 |
1973年 | 14454篇 |
1972年 | 13159篇 |
1971年 | 11836篇 |
1970年 | 10384篇 |
1969年 | 10041篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
A patient with chronic anemia is presented who radiologically showed prominent rugae of the stomach. Angiography demonstrated an arteriovenous malformation with a large feeding artery and prominent draining veins. 相似文献
5.
6.
7.
8.
A. A. Kepel' 《Russian Journal of Marine Biology》2000,26(6):450-452
The alga Analipus japonicus (Harv.) Wynne displays a distinct seasonal pattern in its development in Peter the Great Bay (Sea of Japan). In winter and spring, it occurs only in the form of basal crusts, and vertical axes develop in the summer–autumn period. It reproduces mostly asexually from July to November. Algae with unilocular sporangia occur very seldom, only in June and July. 相似文献
9.
Suzanne Camus Sergio Menéndez Kenneth Fernandes Nelly Kua Geng Liu Dimitris P. Xirodimas David P. Lane Jean-Christophe Bourdon 《Cell cycle (Georgetown, Tex.)》2012,11(8):1646-1655
The discovery that the single p53 gene encodes several different p53 protein isoforms has initiated a flurry of research into the function and regulation of these novel p53 proteins. Full-length p53 protein level is primarily regulated by the E3-ligase Mdm2, which promotes p53 ubiquitination and degradation. Here, we report that all of the novel p53 isoforms are ubiquitinated and degraded to varying degrees in an Mdm2-dependent and -independent manner, and that high-risk human papillomavirus can degrade some but not all of the novel isoforms, demonstrating that full-length p53 and the p53 isoforms are differentially regulated. In addition, we provide the first evidence that Mdm2 promotes the NEDDylation of p53β. Altogether, our data indicates that Mdm2 can distinguish between the p53 isoforms and modify them differently. 相似文献
10.
Comparison of bone marrow extracellular matrices. 总被引:1,自引:0,他引:1
M Lee I P Christopherson J M Lehman C J Bennett H T Cheung 《Biochimica et biophysica acta》1999,1428(2-3):300-304
We have compared the structure and composition of adult and fetal bovine bone marrow extracellular matrices. In contrast to fetal bone marrow, adult bone marrow has more oval fenestration and accumulation of adipocytes as well as lower protein content. These differences could be due to remodeling of bone marrow tissue as it develops. Zymogram analysis of matrix metalloproteinase (MMP) and tissue inhibitor of MMP (TIMP) activities showed that fetal, but not adult bone marrow extract contained a 96-kDa MMP and TIMP-1 and -2. These activities may contribute to the structural differences between adult and fetal bone marrow tissues. 相似文献