全文获取类型
收费全文 | 42555篇 |
免费 | 4450篇 |
国内免费 | 28篇 |
出版年
2022年 | 277篇 |
2021年 | 604篇 |
2020年 | 373篇 |
2019年 | 465篇 |
2018年 | 565篇 |
2017年 | 485篇 |
2016年 | 826篇 |
2015年 | 1389篇 |
2014年 | 1662篇 |
2013年 | 2061篇 |
2012年 | 2622篇 |
2011年 | 2622篇 |
2010年 | 1682篇 |
2009年 | 1482篇 |
2008年 | 2263篇 |
2007年 | 2335篇 |
2006年 | 2129篇 |
2005年 | 2053篇 |
2004年 | 2107篇 |
2003年 | 2034篇 |
2002年 | 1881篇 |
2001年 | 813篇 |
2000年 | 703篇 |
1999年 | 750篇 |
1998年 | 600篇 |
1997年 | 500篇 |
1996年 | 431篇 |
1995年 | 448篇 |
1994年 | 445篇 |
1993年 | 413篇 |
1992年 | 552篇 |
1991年 | 512篇 |
1990年 | 517篇 |
1989年 | 447篇 |
1988年 | 459篇 |
1987年 | 436篇 |
1986年 | 426篇 |
1985年 | 475篇 |
1984年 | 420篇 |
1983年 | 395篇 |
1982年 | 388篇 |
1981年 | 381篇 |
1980年 | 322篇 |
1979年 | 378篇 |
1978年 | 340篇 |
1977年 | 274篇 |
1976年 | 260篇 |
1975年 | 250篇 |
1974年 | 270篇 |
1973年 | 220篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
G R Guy J Gordon R H Michell G Brown 《Biochemical and biophysical research communications》1985,131(1):484-491
Resting human tonsillar B cells were stimulated to divide by heat killed Staphylococcus aureus Cowan strain 1 which was shown to induce hydrolysis of phosphatidylinositol 4, 5-bisphosphate known to give rise to diacylglycerol and an increase in cytosolic free calcium. Addition of the diacylglycerols, 1-oleoyl-2 acetyl glycerol or sn-1, 2-dioctanoylglycerol, together with the calcium ionophore ionomycin to B cell cultures induced marked cell proliferation whereas these agents were ineffective when used alone. Both diacylglycerols were shown to compete with [3H] phorbol 12,13 dibutyrate in binding to protein kinase C. These data support the hypothesis that synergism between cytosolic calcium and endogenous diacylglycerol, which activates protein kinase C, is involved in signal transduction in the proliferation of human B cells. 相似文献
62.
63.
64.
Elliott C. Kulakowski Joseph Maturo Stephen W. Schaffer 《Archives of biochemistry and biophysics》1981,210(1):204-209
Cardiac sarcolemma preparations of both pig and rat ventricles were found to possess two sets of taurine-binding components. The two proteins from pig heart were solubilized with the detergent Ammonyx-Lo. Characterization of these solubilized proteins revealed that both components are glycoproteins and retain the binding properties observed for the membrane isolate. However, the characterization also revealed several differences between the proteins including their binding specificities, their affinities for taurine, their binding isotherms, and their molecular sizes. Possible functions of these two taurine-binding proteins are discussed. 相似文献
65.
66.
New mutations in the pRM promoter of bacteriophage lambda 总被引:1,自引:0,他引:1
67.
68.
Oliver M. Brown 《Life sciences》1981,28(7):819-825
The distribution of acetylcholine (ACh) in the cat heart was investigated by pyrolysis-gas chromatography (PGC) and pyrolysis-mass fragmentography (PMF) techniques. The hearts were dissected into various regions and homogenized in the presence of butyrycholine (or propionylcholine) as internal standard. The choline esters were isolated and analyzed by PGC or by PMF (at m/e 58). A pattern of distribution for ACh was found to be the same as I have previously described (1,2). Some cats were subjected to either a right or a left unilateral cervical vagotomy 4 weeks before removal and analysis of heart tissue. Hearts from unilateral (right or left) vagotomized cats did not differ from controls in the ACh content of any heart area examined. These results are consistent with the idea that intact parasympathetic neurons may compensate for the denervation following unilateral vagotomy. 相似文献
69.
70.