全文获取类型
收费全文 | 418505篇 |
免费 | 43575篇 |
国内免费 | 192篇 |
出版年
2016年 | 4515篇 |
2015年 | 5950篇 |
2014年 | 7053篇 |
2013年 | 10621篇 |
2012年 | 11488篇 |
2011年 | 11964篇 |
2010年 | 8144篇 |
2009年 | 7474篇 |
2008年 | 10689篇 |
2007年 | 11338篇 |
2006年 | 10674篇 |
2005年 | 10154篇 |
2004年 | 10252篇 |
2003年 | 10015篇 |
2002年 | 9806篇 |
2001年 | 17333篇 |
2000年 | 17374篇 |
1999年 | 13959篇 |
1998年 | 4827篇 |
1997年 | 5139篇 |
1996年 | 4855篇 |
1995年 | 4728篇 |
1994年 | 4628篇 |
1993年 | 4627篇 |
1992年 | 12262篇 |
1991年 | 12065篇 |
1990年 | 12074篇 |
1989年 | 11847篇 |
1988年 | 11162篇 |
1987年 | 10496篇 |
1986年 | 9815篇 |
1985年 | 10232篇 |
1984年 | 8435篇 |
1983年 | 7273篇 |
1982年 | 5610篇 |
1981年 | 5017篇 |
1980年 | 4686篇 |
1979年 | 8078篇 |
1978年 | 6296篇 |
1977年 | 5933篇 |
1976年 | 5670篇 |
1975年 | 6128篇 |
1974年 | 6692篇 |
1973年 | 6564篇 |
1972年 | 6121篇 |
1971年 | 5533篇 |
1970年 | 4767篇 |
1969年 | 4780篇 |
1968年 | 4452篇 |
1967年 | 3806篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
Tumor line specific immunity could be induced in chickens with the use of BCG or CP. Direct contact between bacteria and tumor cells was required for immunity induction, but succeeded only in animals which also had been previously injected with the same bacterial vaccine. While other methods such as iv injected live mitomycin treated tumor was capable of inducing immunity, only BCG or CP mediated immunity was capable of being adoptively transferred in the Winn assay. Bursectomized agamma-globulinemic chickens also produced strong transferable immunity. Crossreactivity between transplant lines was detectable upon rechallenge of immune donors but was not evident upon adoptive immunity transfer. Immunity was detectable in the spleen and in peripheral blood lymphocytes but could not be transferred by thymus cells. 相似文献
992.
993.
994.
Isoproterenol (ISO) was injected in 5 mg/kg i.p. doses to rats, daily for two weeks. We evaluated the developed myocardial hypoxia and necrosis quantitatively by histological methods. To follow the time course of cardioprotection prostacyclin or 7-oxo-PGI2 were injected daily, i.p. 5, 30 min and 1, 2, 3, 4 hours before or after the ISO to groups of ten rats, respectively. Cardioprotection was defined as the reduction of necrotized areas and was expressed as percentage change compared to the control (saline treated) group. 1 microgram/kg PGI2 and 50 micrograms/kg 7-oxo-PGI2+ showed nearly equipotent cardioprotection (37.3-7.9% and 38.3-6.8%, respectively). The peak effect of both compounds appeared when injected prior to ISO in the 120. min but the action of 7-oxo-PGI2 was more prolonged. The different doses of prostacyclin analogs given after the ISO injection were ineffective with the exception of 50 micrograms/kg 7-oxo-PGI2 (29.75 +/- 5.2%). 相似文献
995.
996.
997.
998.
999.
1000.