全文获取类型
收费全文 | 6016篇 |
免费 | 854篇 |
国内免费 | 3篇 |
专业分类
6873篇 |
出版年
2021年 | 79篇 |
2019年 | 56篇 |
2016年 | 87篇 |
2015年 | 134篇 |
2014年 | 169篇 |
2013年 | 216篇 |
2012年 | 272篇 |
2011年 | 273篇 |
2010年 | 156篇 |
2009年 | 158篇 |
2008年 | 227篇 |
2007年 | 206篇 |
2006年 | 217篇 |
2005年 | 200篇 |
2004年 | 217篇 |
2003年 | 165篇 |
2002年 | 195篇 |
2001年 | 177篇 |
2000年 | 193篇 |
1999年 | 173篇 |
1998年 | 104篇 |
1997年 | 58篇 |
1996年 | 74篇 |
1995年 | 89篇 |
1994年 | 78篇 |
1993年 | 74篇 |
1992年 | 144篇 |
1991年 | 148篇 |
1990年 | 127篇 |
1989年 | 143篇 |
1988年 | 136篇 |
1987年 | 121篇 |
1986年 | 107篇 |
1985年 | 95篇 |
1984年 | 88篇 |
1983年 | 88篇 |
1982年 | 60篇 |
1981年 | 71篇 |
1980年 | 56篇 |
1979年 | 100篇 |
1978年 | 69篇 |
1977年 | 79篇 |
1976年 | 69篇 |
1975年 | 77篇 |
1974年 | 94篇 |
1973年 | 74篇 |
1972年 | 78篇 |
1971年 | 67篇 |
1970年 | 66篇 |
1968年 | 55篇 |
排序方式: 共有6873条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Anthony Green 《BMJ (Clinical research ed.)》1964,2(5418):1200-1201
105.
Simian Virus 40 Transformation and the Period of Cellular Deoxyribonucleic Acid Synthesis 总被引:3,自引:1,他引:2 下载免费PDF全文
The antiviral agents interferon and statolon protected cells of the mouse line 3T3 against the transforming effect of simian virus 40. Loss of ability of these agents to protect when added some time after infection indicated that the transformation was already fixed. The cells of exponentially growing cultures became resistant to the protective effect of interferon at a linear rate after infection; after one cell generation, the whole population was resistant. By use of synchronous cultures, it was shown that, in cells passing though the G-1 period of the growth cycle, the transformation did not pass the interferon-sensitive stage, whereas cells in S [the period of cellular deoxyribonucleic acid (DNA) synthesis] readily passed this stage (i.e., became interferon-resistant). An irreversible step in transformation appeared to occur in cells synthesizing DNA, and it seems likely that replicating cellular DNA was the target of the viral action. 相似文献
106.
Green NM 《The Biochemical journal》1966,101(3):774-780
1. The reaction between avidin and biotin was found to be exothermic, ΔH being −20·3kcal./mole of biotin bound. The corresponding value of ΔH for streptavidin was −23kcal./mole. 2. The heat evolved was independent of the pH (between 5 and 9), of the buffer (borate or ammonia) and of the fractional saturation of the avidin with biotin. 3. The entropy change for the reaction was zero, and it is suggested that the entropy increase to be expected from hydrophobic interactions was counterbalanced by a decrease in entropy accompanying the formation of buried hydrogen bonds. 4. Modification of the potential hydrogen-bonding sites of the imidazolidone ring led to a decreased heat output and a positive entropy of reaction. 相似文献
107.
Free fatty acid metabolism in Chinese hamsters 总被引:1,自引:0,他引:1
108.
109.
110.
Disinfection of Aerosolized Pathogenic Fungi on Laboratory Surfaces: II. Culture Phase 总被引:2,自引:0,他引:2 下载免费PDF全文
Richard H. Kruse Theron D. Green Richard C. Chambers Marian W. Jones 《Applied microbiology》1964,12(2):155-160
The effect of several fungicides on laboratory surfaces contaminated with the culture (spore) phase of aerosolized Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma capsulatum was ascertained. The culture (spore) phase was more resistant to the action of the fungicides than was the tissue (yeast) phase. The addition of a wetting agent increased the efficiency of several fungicides. The time required for disinfection with a given concentration of fungicide, or the concentration required to disinfect within a given time, can be determined by interpolating the plotted graphs. 相似文献