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   1075645篇
  免费   71831篇
  国内免费   1366篇
耳鼻咽喉   15016篇
儿科学   34649篇
妇产科学   28639篇
基础医学   153503篇
口腔科学   29690篇
临床医学   94973篇
内科学   203822篇
皮肤病学   24407篇
神经病学   81497篇
特种医学   43057篇
外国民族医学   201篇
外科学   163200篇
综合类   21717篇
现状与发展   1篇
一般理论   263篇
预防医学   74651篇
眼科学   24539篇
药学   86123篇
  7篇
中国医学   2806篇
肿瘤学   66081篇
  2019年   7760篇
  2018年   11303篇
  2017年   8916篇
  2016年   10105篇
  2015年   11273篇
  2014年   15285篇
  2013年   22211篇
  2012年   30567篇
  2011年   32316篇
  2010年   18959篇
  2009年   17823篇
  2008年   29975篇
  2007年   32103篇
  2006年   32726篇
  2005年   31063篇
  2004年   29750篇
  2003年   28582篇
  2002年   27550篇
  2001年   60047篇
  2000年   61506篇
  1999年   50953篇
  1998年   12457篇
  1997年   11015篇
  1996年   11029篇
  1995年   10331篇
  1994年   9353篇
  1993年   8869篇
  1992年   37818篇
  1991年   36302篇
  1990年   35765篇
  1989年   34313篇
  1988年   30891篇
  1987年   30018篇
  1986年   28245篇
  1985年   26490篇
  1984年   19202篇
  1983年   16127篇
  1982年   8838篇
  1979年   17050篇
  1978年   11416篇
  1977年   10238篇
  1976年   8842篇
  1975年   10072篇
  1974年   11667篇
  1973年   11281篇
  1972年   10760篇
  1971年   10096篇
  1970年   9263篇
  1969年   8943篇
  1968年   7921篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Trazodone hydrochloride is an oral antidepressant agent which has been associated with the improvement of erections in impotent men and the development of prolonged erections or priapism in potent men. An in vivo study in animal and human subjects was performed to gain experience with the effect of intracavernosal trazodone. In the anesthetized New Zealand White rabbit, intracavernosal trazodone or its major metabolite m-chlorophenylpiperazine (m-CPP) produced full penile erection in 76% and 84% of animals studied respectively with doses ranging from one to 15 mg. On the other hand, intracavernosal administration of five mg. papaverine resulted in a prolonged erection in 90% of animals studied. In 13 selected volunteer patients, intracavernosal trazodone caused tumescence but not full penile erection with corporal body pressures of 28.2 +/- 5.8 mm. Hg. Intracavernosal papaverine or papaverine and phentolamine in these subjects resulted in significantly higher corporal body pressures of 58 +/- 18 mm. Hg (p less than .05). Intracavernosal administration of alpha adrenoceptor agonists but not normal saline resulted in complete detumescence of trazodone- or m-CPP-induced prolonged erection in the animal studies. Intracavernosal trazodone results in erectile activity that appears in part based on its local alpha blocking activity but like other intracavernosal alpha-blocking agents is not as effective in initiating penile erections as are intracavernosal agents that directly induce smooth muscle relaxation.  相似文献   
993.
994.
995.
We evaluated a commercially available polyclonal antibody to 17 beta-estradiol as the basis for an estrogen receptor (ER) assay of breast carcinoma in formalin-fixed paraffin tissues and then compared it with both the ER-ICA antibody in serial paraffin sections and the biochemical assay of corresponding fresh tissue. Using the estradiol antibody, 49 of 50 cases showed some cytoplasmic staining; 38 cases had nuclear staining. Sensitivity and specificity for different proportions of positive nuclear and cytoplasmic staining were calculated using receiver-operator characteristic curves. The optimum correlation with the biochemical assay was obtained with nuclear staining alone. Greater than 30% nuclear positivity as a cut-off point yielded a sensitivity of 76% and a specificity of 82%. The corresponding ER-ICA values in 38 cases yielded a sensitivity of 93% and a specificity of 56%. The methodology for the ER-ICA assay was more technically demanding in paraffin sections than that of the estradiol antibody and considerably more expensive. This study is the first to show that with nuclear staining only, and not cytoplasmic staining, as the parameter of positivity, the immunocytochemical assay of ER with anti-17 beta-estradiol antibody in routinely processed, formalin-fixed, archival material is an accurate and specific method for the determination of the ER status of breast carcinoma.  相似文献   
996.
997.
A case of Beh?et disease associated with aortic valve regurgitation treated with aortic valve replacement is reported. The patient was treated successfully with special surgical techniques for prevention of post operative paravalvular leakage and occurrence of pseudo aneurysm because the patient was under long-term steroid therapy for Beh?et disease.  相似文献   
998.
Chronic alcohol treatment induces a variety of effects on the metabolism of neurotransmitters and the function of their receptors. Recent studies on alcohol dependence and/or functional tolerance to alcohol have clearly demonstrated that neurotransmitter-gated and receptor-coupled ion channels, as well as neurotransmitter receptor coupled with intracellular mediator systems, such as phosphatidylinositides and cyclic nucleotide-generating systems, are invariably suppressed during alcohol dependence. Future studies on the central actions of alcohol and on alcohol dependence should therefore be directed at the molecular changes in synaptic membrane-bound components such as neurotransmitter receptors, as well as on neurotransmitter release and relevant membrane-bound enzymes.  相似文献   
999.
1000.
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