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   121490篇
  免费   6328篇
  国内免费   182篇
耳鼻咽喉   1804篇
儿科学   5381篇
妇产科学   4061篇
基础医学   17326篇
口腔科学   2928篇
临床医学   8808篇
内科学   22964篇
皮肤病学   3468篇
神经病学   9513篇
特种医学   5356篇
外国民族医学   32篇
外科学   19659篇
综合类   1613篇
一般理论   30篇
预防医学   6129篇
眼科学   3451篇
药学   8452篇
中国医学   327篇
肿瘤学   6698篇
  2018年   973篇
  2017年   849篇
  2016年   1170篇
  2015年   1336篇
  2014年   1728篇
  2013年   2518篇
  2012年   3346篇
  2011年   3391篇
  2010年   2121篇
  2009年   2101篇
  2008年   3514篇
  2007年   3769篇
  2006年   3928篇
  2005年   4020篇
  2004年   3963篇
  2003年   3828篇
  2002年   3785篇
  2001年   7161篇
  2000年   7098篇
  1999年   5992篇
  1998年   1684篇
  1997年   1613篇
  1996年   1375篇
  1995年   1252篇
  1994年   1136篇
  1993年   1149篇
  1992年   3832篇
  1991年   3630篇
  1990年   3622篇
  1989年   3416篇
  1988年   3032篇
  1987年   2953篇
  1986年   2854篇
  1985年   2672篇
  1984年   1978篇
  1983年   1620篇
  1982年   948篇
  1981年   943篇
  1980年   779篇
  1979年   1853篇
  1978年   1369篇
  1977年   1134篇
  1976年   963篇
  1975年   1198篇
  1974年   1240篇
  1973年   1211篇
  1972年   1054篇
  1971年   984篇
  1970年   893篇
  1969年   806篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Trypsin and Zymosan induce an increase in respiration activity of cultivated endothelial cells. These effects are not due to the production of oxygen radicals. The effect of trypsin will be explained by interfering with the cellular homeostasis of calcium. The stimulated respiration after incubation with zymosan may be connected with the increased phagocytosis.  相似文献   
82.
83.
Conformationally restricted analogues of the selective partial muscarinic agonist N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide (BM 5; 2) were synthesized. The compounds were tested for muscarinic and antimuscarinic activity in the isolated guinea pig ileum and in intact mice. They were found to be moderately potent muscarinic antagonists or weak partial agonists. The new compounds were less potent than 2 in inhibiting (-)-[3H]-N-methylscopolamine binding in the rate cerebral cortex. Thus, structural modifications of 2 in which part of the amide moiety has been connected with the methyl group in the butynyl chain to form a five-membered ring decrease affinity and in most cases abolish efficacy.  相似文献   
84.
85.
The duodenal contents were examined in 81 patients with gastroduodenal ulcer. Bile acid concentrations, alkaline phosphatase activity, and sodium ion concentration were measured for the detection of duodenogastric reflux. Measurements of sodium ion concentration permitted estimation of the immediate volume of the duodenogastric reflux in the gastric contents. No methods for duodenogastric reflux detection should be given preference in examinations of peptic ulcer patients. Multiple-modality studies appear to be the most effective.  相似文献   
86.
The analysis of vestibular responses in a comatose patient often provides the critical information for making a correct preliminary diagnosis and directing the subsequent laboratory evaluation. Because of some uncertainties about what is being tested with the various bedside maneuvers that are used to elicit vestibular responses, we review the physiologic basis for the oculomotor responses that occur with head rotation or with caloric stimuli. We further urge precise and unambiguous terminology to describe both stimulus and response. We suggest using physiologically well-defined terms such as vestibulo-ocular reflex and cervico-ocular reflex and avoiding potentially misleading terms such as the doll's head and the oculocephalic maneuvers.  相似文献   
87.
88.
Influence of mesh materials on collagen deposition in a rat model.   总被引:5,自引:0,他引:5  
Alterations of the extracellular matrix (ECM) with its major component collagen are increasingly discussed as possible risk factors implicated in the development of abdominal-wall herniation. Because of the widespread use of alloplastic meshes for the surgical repair of hernias, an animal study was performed to analyze the influence of various mesh materials on the quantity and quality of collagen deposition. In 60 male Sprague-Dawley rats an abdominal replacement was performed using three different kinds of mesh materials: polyester (PE), a pure polypropylene (PP), and a composite mesh made of polypropylene and polyglactin (PG). A simple fascia suture repair served as control. The count of fibroblasts, the collagen/protein ratio, the type I/III collagen ratio, and the expression of basic fibroblast growth factor (b-FGF) at the interface were analyzed after 7, 21, and 90 days. The ratio of collagen to overall protein (microg/mg) showed significant differences comparing different mesh materials (sham controls 38.44 +/- 16.33 microg/mg, PE 68.5 +/- 23.8 microg/mg, PP 101.6 +/- 32.3 microg/mg, PG 49.6 +/- 11.6 microg/mg at day 90). The ratio of collagen type I/III increased over time in all groups. However, 90 days after mesh implantation the ratio was always significantly lowered compared to the controls. No significant difference was found comparing different mesh materials. The alteration of the scar composition is closely connected to an increased b-FGF expression. b-FGF and count of fibroblasts highly correlated (r =.95) and showed significant elevated levels compared to simple suture repair. The results of our study strongly support the notion that wound healing is affected by mesh implantation. The quality of the ECM deposition as determined by collagen type I/III ratio is impaired in general, whereas the quantity of ECM deposition is markedly influenced by the kind of mesh material.  相似文献   
89.
A total of 117 manic-depressives who had been on lithium for a mean duration of 4.7 years were examined before lithium therapy and subsequently at intervals. Information relating to pre-lithium height and weight and current weight were determined and used to calculate the body mass index (BMI) for each individual. Other relevant variables such as age, sex, cumulative lithium dose, duration of therapy, thyroid profile and serum lithium levels were recorded. The results indicated that, although there was a nonsignificant increase in BMI for the whole population, lithium and sex were not significant predictors of any increase in BMI. In nearly 27% of patients BMI actually slightly decreased during lithium therapy. The overall conclusions from this study are that, in the population studied, lithium may not have exerted any pharmacological effects to increase BMI.  相似文献   
90.
1. Continuous infusion of oxytocin (0.33 u min-1) accelerated gastric emptying of semisolid TC-99m labelled Chelex-100 resin/oatmeal in 10 healthy volunteers under basal conditions. 2. Administration of oxytocin did not change the pattern of gastric emptying delayed by pethidine. 3. The emptying pattern of semisolid has confirmed the existence of a lag phase.  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