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   106673篇
  免费   6870篇
  国内免费   814篇
耳鼻咽喉   1162篇
儿科学   3178篇
妇产科学   2662篇
基础医学   14633篇
口腔科学   2621篇
临床医学   8669篇
内科学   23690篇
皮肤病学   2265篇
神经病学   10006篇
特种医学   4018篇
外国民族医学   25篇
外科学   14370篇
综合类   1763篇
一般理论   53篇
预防医学   6701篇
眼科学   1804篇
药学   8595篇
  3篇
中国医学   591篇
肿瘤学   7548篇
  2023年   433篇
  2022年   981篇
  2021年   2087篇
  2020年   1323篇
  2019年   1923篇
  2018年   2418篇
  2017年   1761篇
  2016年   1945篇
  2015年   2229篇
  2014年   2963篇
  2013年   4265篇
  2012年   5769篇
  2011年   6021篇
  2010年   3783篇
  2009年   3337篇
  2008年   5221篇
  2007年   5458篇
  2006年   5134篇
  2005年   4849篇
  2004年   5043篇
  2003年   4941篇
  2002年   4925篇
  2001年   3879篇
  2000年   3804篇
  1999年   3095篇
  1998年   1276篇
  1997年   1004篇
  1996年   917篇
  1995年   865篇
  1994年   762篇
  1993年   754篇
  1992年   1861篇
  1991年   1830篇
  1990年   1559篇
  1989年   1532篇
  1988年   1395篇
  1987年   1245篇
  1986年   1237篇
  1985年   1078篇
  1984年   817篇
  1983年   728篇
  1982年   479篇
  1981年   424篇
  1979年   592篇
  1978年   436篇
  1975年   445篇
  1974年   503篇
  1973年   475篇
  1972年   434篇
  1971年   406篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
71.
Rat brain hippocampal slices were incubated with or without the convulsant 4-aminopyridine (4-AP). From these slices a crude mitochondrial/synaptosomal membrane fraction was prepared and analyzed for endogenous protein phosphorylation. 4-AP (10(-5) M) stimulated the phosphorylation of a 50 kDa protein by 86%. The phosphorylation of this 50 kDa protein is Ca2+/calmodulin-dependent and we suggest that this protein is the lower molecular weight subunit of Ca2+/calmodulin-dependent protein kinase II (CaMK II).  相似文献   
72.
A longitudinal survey (February 1984 - January 1985) on the incidence of acute diarrhea episodes in a sample of 8,164 children (aged 0–12 years) living in southeastern Sicily was carried out by means of weekly telephone interviews with doctors practising in the territory. The incidence rate was 0.479 (0.472–0.485 95% C.I.) per child per year and the frequency of episodes was significantly higher (p < 0.001) in children aged 0–4 years (0.86). Diarrhea was more frequent in industrial areas than in rural ones, and almost half (45.1%) of the total episodes had a mild course. No death from diarrhea occurred and admission to hospital was reported for 8.4% of all cases.Corresponding author.  相似文献   
73.
目的:探讨周围血管损伤自全大隐静脉移植治疗的方法。适应证和治疗效果。方法:回顾性分析22例周围血管损伤自体大隐静脉移植治疗的临床资料,并阐述了术中注意事项,提出最佳手术时机及预后情况。结果:22例均采用自体大隐静脉移植,痊愈19例(86.4%)。截肢3例(13.6%),22例患者无死亡,随访2-9年,20例肢体功能恢复满意,2例移植段狭窄,但肢体功能良好。结论:自体大隐静脉移植是治疗周围血管损伤行之有效的方法之一。血管吻合的时间应在24h以内,最佳为8h以内。  相似文献   
74.
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.  相似文献   
75.
Is interleukin 2 a neuromodulator in the brain?   总被引:5,自引:0,他引:5  
A bidirectional flow of information exists between the CNS and the neuroendocrine and immune systems, representing an important homeostatic mechanism in the body. Lymphokines and other products of immunocompetent cells seem to play a crucial role in this communication and seem to exert powerful effects on neurones in the brain. In this article, Giuseppe Nisticò and Giovambattista De Sarro describe the central effects following interleukin 2 (IL-2) microinfusion into several areas of the rat brain. The locus coeruleus seems to be the main site in the brain through which IL-2 exerts soporific effects. In addition, the possible transducing mechanisms coupling IL-2 receptor stimulation and the electroencephalogram (EEG) spectrum power responses elicited from the locus coeruleus seem to involve stimulation of specific receptors coupled to adenylate cyclase through a Gi protein.  相似文献   
76.
77.
78.
79.
Choriocarcinoma is one of the most serious forms of gestational trophoblastic tumor. It is a malignant tumor from the epithelium of the chorionic villi. The most frequent location site is the uterus. Associated with ectopic pregnancy, it is extremely rare and in general, very aggressive. In 75% of the cases, it items from distant metastasis; therefore, a histological examination of the tubes must be performed in all ectopic pregnancies. Our patient was a 33-year-old woman who was admitted to emergency room (ER) with an intense pain in the right, iliac cavity, and limited genital bleeding. During the exploration, there was abdominal pain, with doubtful signs of peritoneal irritation. The vaginal ultrasound offered an image that was compatible with an extra uterine pregnancy in the left appendages. At emergency, right salpingectomy was performed via laparotomy. The patient was treated with polychemotherapy and contraceptives for a year, with no recurrence of the disease. Control follow-up was performed using beta-human chorionic gonadotropin (HCG) testing on a weekly basis during the first month and then bi-monthly during the first year of follow-up.  相似文献   
80.
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