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   129773篇
  免费   6655篇
  国内免费   156篇
耳鼻咽喉   2288篇
儿科学   6382篇
妇产科学   4460篇
基础医学   16984篇
口腔科学   3777篇
临床医学   9307篇
内科学   24158篇
皮肤病学   3753篇
神经病学   9854篇
特种医学   5673篇
外国民族医学   32篇
外科学   22166篇
综合类   1741篇
一般理论   36篇
预防医学   6233篇
眼科学   3804篇
药学   8816篇
  1篇
中国医学   411篇
肿瘤学   6708篇
  2019年   850篇
  2018年   1328篇
  2017年   1151篇
  2016年   1531篇
  2015年   1540篇
  2014年   2112篇
  2013年   3102篇
  2012年   3875篇
  2011年   4064篇
  2010年   2475篇
  2009年   2270篇
  2008年   4030篇
  2007年   4343篇
  2006年   4502篇
  2005年   4587篇
  2004年   4575篇
  2003年   4388篇
  2002年   4337篇
  2001年   7505篇
  2000年   7471篇
  1999年   6238篇
  1998年   1728篇
  1997年   1650篇
  1996年   1440篇
  1995年   1257篇
  1994年   1135篇
  1993年   1156篇
  1992年   3804篇
  1991年   3615篇
  1990年   3589篇
  1989年   3392篇
  1988年   3007篇
  1987年   2912篇
  1986年   2825篇
  1985年   2636篇
  1984年   1959篇
  1983年   1607篇
  1982年   935篇
  1981年   927篇
  1979年   1833篇
  1978年   1359篇
  1977年   1120篇
  1976年   944篇
  1975年   1186篇
  1974年   1227篇
  1973年   1211篇
  1972年   1054篇
  1971年   980篇
  1970年   881篇
  1969年   793篇
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
91.
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   
92.
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   
93.
94.
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   
95.
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   
96.
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   
97.
98.
New parametric and non parametric statistical methods have been compared in the evaluation of experimental data of CEA and CA 19.9 using a brief program in BASIC. We have found that the distribution of the two markers is the same of that described in literature except for both the means that we have found being slightly higher than that ones described by other authors.  相似文献   
99.
A new rapid procedure for desiccating frozen resin-cracked retinal tissue for scanning electron microscopy (SEM) which permits air-drying was found to compare favorably with tissues prepared by critical-point drying: Retinal tissue was fixed in 4% phosphate-buffered neutral formaldehyde, dehydrated by means of graded ethanol, embedded in Epon, cracked and washed in propylene oxide. For desiccation, the specimens were immersed in hexamethyldisilazane (HMDS), air-dried and finally sputter-coated. The method is time-saving, gives extended information in SEM, and the number of good specimens is increased.  相似文献   
100.
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