首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18651篇
  免费   1234篇
  国内免费   6篇
  2023年   167篇
  2022年   319篇
  2021年   612篇
  2020年   449篇
  2019年   577篇
  2018年   697篇
  2017年   607篇
  2016年   812篇
  2015年   1073篇
  2014年   1166篇
  2013年   1332篇
  2012年   1460篇
  2011年   1368篇
  2010年   814篇
  2009年   744篇
  2008年   875篇
  2007年   868篇
  2006年   786篇
  2005年   661篇
  2004年   605篇
  2003年   549篇
  2002年   466篇
  2001年   346篇
  2000年   312篇
  1999年   251篇
  1998年   113篇
  1997年   98篇
  1996年   82篇
  1995年   78篇
  1994年   77篇
  1993年   65篇
  1992年   133篇
  1991年   106篇
  1990年   74篇
  1989年   96篇
  1988年   80篇
  1987年   99篇
  1986年   90篇
  1985年   70篇
  1984年   69篇
  1983年   48篇
  1982年   39篇
  1981年   46篇
  1980年   29篇
  1979年   59篇
  1978年   37篇
  1976年   34篇
  1975年   40篇
  1974年   33篇
  1973年   48篇
排序方式: 共有10000条查询结果,搜索用时 906 毫秒
101.
Immunization of C57BL/6 mice with BCGcw stimulated a population of "suppressor cells" which had a decreased capacity to induce the graft-versus-host response. The graft-versus-host response was quantitated using the Simonsen splenomegaly assay. F1 mice (C57BL/6 X CBA) were inoculated intraperitoneally with 1 X 10(8) parental (C57BL/6) or (CBA) spleen cells. The F1 mice were sacrificed 13 days later and the resulting splenomegaly was 3-4 times the normal amount. F1 mice which were injected with parental BCGcw-primed C57BL/6 spleen cells had a 50% inhibition of splenomegaly, whereas BCGcw-primed CBA spleen cells (a strain which does not develop suppressor cells) did not show this inhibition. In vitro results also confirmed that only C57BL/6 mice and not CBA mice developed suppressor cells after BCGcw immunization. A second study showed that X-irradiated (1000 R) BCGcw-primed "suppressor cells" could inhibit splenomegaly caused by the inoculation of normal parental C57BL/6 cells into F1 mice. The mechanism by which BCGcw-primed "suppressor cells" caused this inhibition of splenomegaly was delineated and found to be dependent upon the secretion of prostaglandin (PGE-1). Indomethacin and aspirin, potent inhibitors of prostaglandin synthesis, blocked the activity of C57BL/6 BCGcw "suppressor cells" and splenomegaly resulted. Systemic administration of the prostaglandin (15S)-15-methyl PGE-1 reduced splenomegaly approximately 50% in F1 mice which were injected with C57BL/6 or CBA cells. These results indicated that immunization with BCGcw stimulated a population of "suppressor cells" which could cause a decrease in graft-versus-host response and that the secretion of prostaglandin was responsible for this inhibition.  相似文献   
102.
Cell and Tissue Research - Cerebrospinal fluid (CSF)-contacting neurons were studied by means of electron microscopy in the spinal cord and/or terminal ventricle of the ray, Raja clavata...  相似文献   
103.
104.
105.
Three patients with progressive coccidioidomycosis were given preparations of transfer factor (TF). Adverse reactions to TF were minimal. Following TF administration two of these patients had prolonged clinical remissions in their coccidioidal disease. Cellular immune responses were sequentially evaluated by coccidioidininduced delayed-type skin tests, lymphocyte blast transformation and macrophage inhibition factor production (MIF). These three patients each exhibited different cellular immune patterns before and after TF administration. Two patients converted their coccidioidin skin tests, and one converted lymphocyte transformation response to coccidioidin. Also, TF apparently favorably affected the MIF response in all three patients.  相似文献   
106.
107.
108.
109.
Summary The fluorescent antibody technique was used to study antigenic relationships betweenParacoccidioides loboi and other pathogenic fungi. The findings suggest thatP. loboi is more closely related antigenically to certainP. brasiliensis strains than to others and that it has antigens in common with the yeast form ofHistoplasma capsulatum, H. duboisii, Blastomyces dermatitidis, Candida albicans and also the mycelial form ofCoccidioides immitis. Serum globulins from 3 cases of keloidal blastomycosis were labelled with fluorescein isothiocyanate. These conjugates showed slight or no reactivity withP. loboi, the yeast forms ofP. brasiliensis, H. capsulatum, H. duboisii andB. dermatitidis, However, they stained brightlyC. albicans, serotypes A and B, the tissue form ofC. immitis and the yeast form ofSporotrichum schenckii. Adsorption of these reagents withC. albicans eliminated all staining except that forS. schenckii. These patients had no history of clinical sporotrichosis.Deceased. Last address: Fundacão Gonçalo Moniz, Salvador, Bahia, Brazil. Requests for reprints should be sent to Dr.William Kaplan.Dr.Miranda is in private practice in Rio de Janeiro, Brazil.  相似文献   
110.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号