全文获取类型
收费全文 | 8143篇 |
免费 | 846篇 |
国内免费 | 2篇 |
出版年
2021年 | 114篇 |
2020年 | 70篇 |
2019年 | 96篇 |
2018年 | 108篇 |
2017年 | 99篇 |
2016年 | 187篇 |
2015年 | 275篇 |
2014年 | 342篇 |
2013年 | 411篇 |
2012年 | 459篇 |
2011年 | 493篇 |
2010年 | 312篇 |
2009年 | 300篇 |
2008年 | 412篇 |
2007年 | 428篇 |
2006年 | 379篇 |
2005年 | 350篇 |
2004年 | 370篇 |
2003年 | 339篇 |
2002年 | 344篇 |
2001年 | 159篇 |
2000年 | 155篇 |
1999年 | 162篇 |
1998年 | 123篇 |
1997年 | 103篇 |
1996年 | 110篇 |
1995年 | 86篇 |
1994年 | 80篇 |
1993年 | 92篇 |
1992年 | 117篇 |
1991年 | 117篇 |
1990年 | 113篇 |
1989年 | 80篇 |
1988年 | 80篇 |
1987年 | 84篇 |
1986年 | 69篇 |
1985年 | 88篇 |
1984年 | 83篇 |
1983年 | 76篇 |
1982年 | 65篇 |
1981年 | 71篇 |
1980年 | 56篇 |
1979年 | 48篇 |
1978年 | 53篇 |
1977年 | 45篇 |
1976年 | 49篇 |
1975年 | 45篇 |
1974年 | 47篇 |
1973年 | 45篇 |
1971年 | 40篇 |
排序方式: 共有8991条查询结果,搜索用时 0 毫秒
101.
Selective Inhibition of Reovirus Ribonucleic Acid Synthesis by Cycloheximide 总被引:27,自引:18,他引:9 下载免费PDF全文
Cycloheximide, at a concentration of 10 mug/ml, rapidly blocked protein synthesis in L cells infected with reovirus. When the drug was added before 5 hr postinfection, synthesis of both single- and double-stranded varieties of virus-specific ribonucleic acid (RNA), which normally commences between 6 and 7 hr after infection, was blocked. When the cycloheximide was added at 9 hr after infection, uptake of uridine-H(3) into RNA, for the succeeding 6 hr at least, was similar to that of an infected culture without the drug. This latter uptake of uridine-H(3) in the presence of cycloheximide was largely into single-stranded RNA, since double-stranded RNA synthesis was rapidly and markedly inhibited by the cycloheximide. Single-stranded RNA formed in the presence of cycloheximide was found not to be a precursor of viral progeny, double-stranded RNA. Synthesis of double-stranded RNA in the infected cell probably requires prior synthesis of a new protein, which has a rapid rate of turnover. The possibility that formation of single-stranded RNA is preceded by synthesis of a second new protein is discussed. 相似文献
102.
Separation of the antihemophilic factor (F. 8) from fibrinogen with thrombin and manganese chloride 总被引:2,自引:0,他引:2
103.
104.
105.
106.
107.
P. H. Graham 《Antonie van Leeuwenhoek》1965,31(1):349-354
This paper reports an investigation of the extracellular polysaccharides produced by 26 strains ofRhizobium andAgrobacterium. Strains ofRhizobium leguminosarum andR. phaseoli produced a water-soluble polysaccharide containing glucose, glucuronic acid and 4-0-methylglucuronic acid. These substances were also identified in the polysaccharide of a single strain fromLotus uliginosus. Glucose was the only detectable component in the polysaccharide produced by strains ofAgrobacterium radiobacter andA. tumefaciens. The polysaccharides obtained from slow-growing rhizobia were not freely water-soluble. Glucose, mannose, rhamnose, galactose and 4-0-methylglucuronic acid were identified as components of this extracellular material.These results are related to previous studies on rhizobial taxonomy and to the infection process in legumes. 相似文献
108.
1. An ALGOL computer programme is presented for the calculation of the results of amino acid analysis. 2. The suggestion is made that a similar approach could be made to other tedious and repetitive biochemical calculations. 相似文献
109.
Skin homografts were applied to patients with cervical cancer. In 9% (10 of 110) of untreated patients, grafts survived for more than two weeks. The frequency of prolonged graft survival was increased by pelvic surgery or radiotherapy. It was highest, 62% (34 of 55), in those with recurrent cancer. Recurrence and death in patients studied prior to treatment and followed up six months to two and a half years was three times more frequent in those with grafts tolerated over two weeks than in those rejecting them in a shorter period, i.e. five of 10 and 10 of 74, respectively. 相似文献
110.