全文获取类型
收费全文 | 9071篇 |
免费 | 741篇 |
国内免费 | 3篇 |
专业分类
9815篇 |
出版年
2023年 | 63篇 |
2022年 | 126篇 |
2021年 | 211篇 |
2020年 | 123篇 |
2019年 | 170篇 |
2018年 | 223篇 |
2017年 | 179篇 |
2016年 | 298篇 |
2015年 | 419篇 |
2014年 | 434篇 |
2013年 | 524篇 |
2012年 | 693篇 |
2011年 | 644篇 |
2010年 | 445篇 |
2009年 | 338篇 |
2008年 | 478篇 |
2007年 | 446篇 |
2006年 | 417篇 |
2005年 | 333篇 |
2004年 | 331篇 |
2003年 | 315篇 |
2002年 | 269篇 |
2001年 | 190篇 |
2000年 | 118篇 |
1999年 | 164篇 |
1998年 | 92篇 |
1997年 | 69篇 |
1996年 | 67篇 |
1995年 | 70篇 |
1994年 | 59篇 |
1993年 | 54篇 |
1992年 | 99篇 |
1991年 | 114篇 |
1990年 | 88篇 |
1989年 | 71篇 |
1988年 | 63篇 |
1987年 | 65篇 |
1986年 | 61篇 |
1985年 | 48篇 |
1984年 | 67篇 |
1983年 | 60篇 |
1982年 | 46篇 |
1981年 | 39篇 |
1980年 | 38篇 |
1979年 | 34篇 |
1978年 | 34篇 |
1977年 | 43篇 |
1976年 | 37篇 |
1975年 | 34篇 |
1973年 | 33篇 |
排序方式: 共有9815条查询结果,搜索用时 0 毫秒
51.
52.
Unequal synthesis of globin chains after extended incubation of rabbit reticulocytes with L-O-methylthreonine 总被引:1,自引:0,他引:1
Rabbit reticulocytes were incubated in vitro as long as 20 hr with l-O-methyl threonine, the OMT was removed, and the capacity of the cells to synthesize α- and β-globin chains was determined. After 20 hr incubation in vitro, OMT-treated cells can make β chains about twice as well as cells incubated for 20 hr without OMT. However, the capacity of OMT-treated cells to synthesize α chains was only about 60% that of cells incubated without OMT for 20 hr. These results suggest that the capacity of reticulocytes to produce a specific globin chain after an in vitro incubation correlates positively with the number of ribosomes associated with the specific messenger RNA for that chain during the incubation. 相似文献
53.
54.
55.
56.
57.
58.
59.
Secondary and Apparent Primary Antibody Responses After Group A Streptococcal Vaccination of 21 Children 总被引:6,自引:0,他引:6 下载免费PDF全文
Benedict F. Massell J. Gabriel Michael Jacqueline Amezcua Myron Siner 《Applied microbiology》1968,16(3):509-518
A partially purified M protein, extracted from a mouse-virulent strain of type 3, group A streptococcus, was administered subcutaneously in gradually increasing amounts at weekly intervals to 21 children in a Family Program. Seven children with type 3 bactericidal antibody in prevaccination sera showed a secondary response. Of 14 children with no detectable type 3 bactericidal antibody prior to vaccination, 13 developed definite type 3 antibody during or soon after vaccination. This response appeared to be of the primary variety in at least some of the 13 children because (i) the total incidence of antibody response (20 of 21) was greater than can be accounted for by the documented incidence of clinical and subclinical type 3 infections among children of our Family Program during a period of 14 years, (ii) the response in the 13 children with no detectable antibody prior to vaccination was more delayed than in those showing a definite secondary response, and (iii) on the average, the amount of vaccine needed for a response in these 13 children was 15 to 28 times greater than that required for the secondary response. Local skin reactions were variable among the vaccinated children. Systemic reactions were infrequent and not severe. The giving of multiple injections of partially purified M protein did not seem to cause cutaneous hypersensitivity. 相似文献
60.