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   2173866篇
  免费   154235篇
  国内免费   3210篇
耳鼻咽喉   31368篇
儿科学   72406篇
妇产科学   59075篇
基础医学   308140篇
口腔科学   59423篇
临床医学   191469篇
内科学   423703篇
皮肤病学   48700篇
神经病学   168021篇
特种医学   86586篇
外国民族医学   860篇
外科学   331941篇
综合类   45003篇
现状与发展   2篇
一般理论   618篇
预防医学   159002篇
眼科学   49028篇
药学   167071篇
  9篇
中国医学   4689篇
肿瘤学   124197篇
  2018年   22452篇
  2017年   17260篇
  2016年   19132篇
  2015年   21521篇
  2014年   29703篇
  2013年   44710篇
  2012年   61252篇
  2011年   64838篇
  2010年   38618篇
  2009年   36433篇
  2008年   61190篇
  2007年   65452篇
  2006年   66363篇
  2005年   64152篇
  2004年   62200篇
  2003年   60106篇
  2002年   58542篇
  2001年   111668篇
  2000年   115631篇
  1999年   97353篇
  1998年   25334篇
  1997年   22678篇
  1996年   23027篇
  1995年   21698篇
  1994年   20194篇
  1993年   18895篇
  1992年   75372篇
  1991年   72969篇
  1990年   71472篇
  1989年   68417篇
  1988年   62509篇
  1987年   61159篇
  1986年   57220篇
  1985年   54496篇
  1984年   40145篇
  1983年   33766篇
  1982年   19047篇
  1981年   17098篇
  1979年   35808篇
  1978年   24468篇
  1977年   21253篇
  1976年   19197篇
  1975年   21287篇
  1974年   24778篇
  1973年   23859篇
  1972年   22373篇
  1971年   20610篇
  1970年   19270篇
  1969年   18071篇
  1968年   16216篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
991.
Supplementation of the diet of adult male rats with 4,000 ppm zinc as ZnSO4 for 30 to 32 days increased the zinc content in the testis and sperm by 25 and 18 per cent respectively, but did not change the same in accessory reproductive tissues, e.g. epididymis, seminal vesicle and prostate. The incidence of conception from mating between normal females and zinc fed males was lower as compared to mating between normal females and control males. This observation indicated reduced fertility of the males resulting from additional zinc ingestion. Motility of the sperm collected from the epididymis (tail) of the zinc treated rats was found to be inhibited. It has been suggested that excess zinc in the sperm was responsible for their poor motility and hence a reduced fertilising capacity.  相似文献   
992.
Survey involved 84 workers matched for age, socio-occupational and families status and divided into 3 groups : A : 27 shift workers on 3 days rotating shift, B : 47 shift workers on 5 days rotating shift, C : 20 days workers. Each subject was submitted to dietary survey by means of 24 hours recall, realised 3 times for shift workers and once for control. All workers were interviewed about caloric intake of the preceding day off caloric intake. Annual weight gain was studied through the use of occupational health service records. There was no significant difference between the 3 groups for working day caloric intake. Day-off intake was lower (p less than 0.05) in group A (day-off any day of the week). Annual weight gain was not different between the 3 groups. Shift workers with faster weight gain had a higher caloric intake on day-off and after evening meal.  相似文献   
993.
994.
995.
Obsessive-compulsive disorder is increasingly recognized in patients of different age groups. Serotonergic agents, such as clomipramine, have been recently found to be useful in the management of this condition. However, unexpected side effects, such as dysphoria, aggressiveness, and paranoid ideation, may occur with therapeutic doses of this compound, as evidenced in the cases of two male adolescents presented here. Possible pathogenetic factors, involving serotonin and serotonin-receptor abnormalities are discussed. Management of these side effects is based on adequate dose reduction and monitorization.  相似文献   
996.
997.
998.
999.
Coexistent primary hyperparathyroidism and monoclonal gammopathy, although rare, has been reported previously by a number of investigators. We report four patients with such an occurrence who were seen between 1976 and 1988. Another patient with primary hyperparathyroidism also had multiple myeloma and was in remission for 12 years. These patients represent approximately 1% of the 386 patients with primary hyperparathyroidism seen during the same 12-year period. Although several mechanisms have been proposed to explain this concurrence, we believe it is the result of a chance occurrence. A review of the literature, an estimate of the chance occurrence of coincidental monoclonal gammopathy, benign or malignant, in patients with primary hyperparathyroidism, and some practical implications of this interesting coexistence are presented.  相似文献   
1000.
Encephalo-myelo-radiculo-ganglionitis presenting as pandysautonomia   总被引:2,自引:0,他引:2  
A 68-year-old man developed pandysautonomia with severe orthostatic dysfunction, fixed heart rate, low serum levels of norepinephrine and epinephrine, absent sympathetic skin responses, and pupillary abnormalities. CSF protein was 92 mg/dl. In spite of a good recovery following corticosteroid administration, a relapse occurred, with accompanying sensory symptoms confined to both arms. Fatal sudden cardiac arrest occurred after 4 months. Autopsy revealed numerous lymphocytic infiltrates, predominantly in autonomic and sensory ganglia and, to a lesser extent, in the nerve roots, spinal cord, and brainstem without evidence for an underlying tumor. This case provides histopathologic evidence for an inflammatory etiology of panautonomic neuropathy in some patients.  相似文献   
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