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   173791篇
  免费   12475篇
  国内免费   5610篇
耳鼻咽喉   1906篇
儿科学   3451篇
妇产科学   4662篇
基础医学   24661篇
口腔科学   4594篇
临床医学   17011篇
内科学   29477篇
皮肤病学   2914篇
神经病学   10757篇
特种医学   6018篇
外国民族医学   45篇
外科学   21915篇
综合类   15396篇
现状与发展   19篇
一般理论   35篇
预防医学   12365篇
眼科学   4566篇
药学   16248篇
  38篇
中国医学   4290篇
肿瘤学   11508篇
  2023年   1320篇
  2022年   3001篇
  2021年   4189篇
  2020年   2896篇
  2019年   2897篇
  2018年   3694篇
  2017年   2939篇
  2016年   2914篇
  2015年   4137篇
  2014年   5206篇
  2013年   5171篇
  2012年   7650篇
  2011年   8409篇
  2010年   4947篇
  2009年   4256篇
  2008年   6177篇
  2007年   6426篇
  2006年   6423篇
  2005年   5992篇
  2004年   4840篇
  2003年   4507篇
  2002年   4109篇
  2001年   7860篇
  2000年   8109篇
  1999年   6958篇
  1998年   2674篇
  1997年   2191篇
  1996年   1585篇
  1995年   1469篇
  1994年   1304篇
  1993年   1083篇
  1992年   4087篇
  1991年   4090篇
  1990年   3820篇
  1989年   3760篇
  1988年   3629篇
  1987年   3428篇
  1986年   3205篇
  1985年   3051篇
  1984年   2088篇
  1983年   1823篇
  1979年   1921篇
  1978年   1184篇
  1975年   1191篇
  1974年   1359篇
  1973年   1415篇
  1972年   1357篇
  1971年   1247篇
  1970年   1137篇
  1969年   1122篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
143.
Both dopamine D1 and D2 receptors are present in rat retina. D1 receptors are positively coupled to adenylyl cyclase, while D2 receptors are negatively coupled. After intraocular administration of the neurotoxin 6-hydroxydopamine (6-OHDA) there is depletion of retinal dopamine by about 90%, as well as a decrease of the number of D1 and D2 receptor binding sites. Following the 6-OHDA lesion, there is an enhancement of the D1 receptor-stimulated accumulation of cyclic-AMP and a loss of D2 receptor-inhibited accumulation of cyclic-AMP. Our results suggest that some of the retinal D2 receptors are coupled to adenylyl cyclase and some are not.  相似文献   
144.
Q Guo  Z Guo 《中西医结合杂志》1989,9(8):472-4, 452
The effect of the traditional Chinese medicinal herbs enema and enteric-coated capsules in the treatment of ulcerative colitis (UC) were compared in 260 cases. The immune complexes and the dynamic change of autoantibodies were monitored in 28 out of the 260 cases before and after treatment. The following results were observed. (1) There was no significant difference in the total effective rate between the enema group and the oral capsule group (93.3% and 87.5% respectively), but the recovery rates of purulent hemafecia, mucusfecia and erosion accompanying colitis, etc. in the former group were higher than those in the latter (P less than 0.01). (2) The circulating immune complexes were found 43 times above the normal range in 17 cases with positive rate 60.7%, and tended to decrease as the condition became better after treatment. Antinuclear antibodies were determined by the indirect fluorescent immune method and the indirect enzyme labelling method and the positive rates were 53.6% and 64.7% respectively, both being much higher than those in the controls (P less than 0.01).  相似文献   
145.
A goal for the obstetrician and neonatologist is to screen for risk factors associated with intraventricular hemorrhage (IVH) in the low-birthweight infant. Perinatal events that lead to neonatal metabolic and cardiovascular derangements seem to provoke IVH, and conflicting reports have implicated labor as being contributory. A fetal heart rate (FHR) abnormality during premature labor may be a predictor of subsequent neonatal IVH. For this reason, 5 years of FHR tracings at two university medical centers were reviewed for inborn infants who were delivered after premature labor and weighed less than or equal to 2000 gm. Sixty-four infants developed IVH, but pre-existing labor with a discernible FHR pattern was recorded in only 38 (59%) cases. Interpretations were reassuring in 17 (45%) cases, suspicious in 7 (18%) cases, and ominous in 14 (37%) cases. This proportion of FHR patterns was not significantly different from a matched group of premature infants without IVH during the same period. Interpretations of intrapartum FHR patterns of low-birthweight infants are limited, especially before 30 weeks gestation, and not useful in predicting neonatal IVH.  相似文献   
146.
随着护理高等教育的发展,越来越多的护理本科生将走向临床,从事护理工作;结合护理本科生的特点,通过一年有计划、有目标、有针对性地规范化培训,可以使新护士尽快适应医院环境,完成从学生到护士的角色改变,更好适应临床护理工作.  相似文献   
147.
OBJECTIVE: To investigate the characteristics of the early stage treponema pallidum infected tissue in ear, nose, oropharynx and larynx and to raise relevance ratio of syphilis in nose and oropharynx and enhance doctor's self-protection awareness. METHODS: The histopathologic characteristics were studied by using HE staining, Warthin-Starry (W-S) staining was adopted to examine the treponema pallidum(TP) in lesion issue and its exudates smear for 12 cases biopsy tissues of suspicious syphilis. The diagnosis was confirmed by venereal disease research laboratory (VDRL), rapid plasma reagin circle test(RPR), treponema pallidum hemagglutination test(TPHA) and fluorescent treponemal antibody-absorption test (FTA-ABS). Treat with curing syphilis methods which published by nation. RESULTS: In the 12 cases mucous membrane specimen, the squamous epithelium proliferated, neutrophilic granulocyte infiltrated, within inherent membrane generous plasmacyte and lymphocyte infiltrated. W-S staining: plenty of treponema pallidum were found inside mucous membrane epithelium and exudate smear. Serology examination: 11 cases VDRL(++++), 7 cases RPR (+), 11 cases TPHA(+), 1 case FTA-ABS(+). After systemic treatment, 11 cases are clinically recovered. All patients serology become negative. CONCLUSION: W-S staining method can directly demonstrate histopathologic characteristics in early syphilis, in intrinsic membrane numerous plasmacyte infiltration. Combining with specific syphilis serology examination could increase diagnosis rate of syphilis in nose and oropharynx.  相似文献   
148.
目的:研究轻度高温、亚低温对大鼠脑缺血再灌注损伤组织兴奋性氨基酸(EAA)与氧自由基的相互关系及病理损伤程度的影响。方法:60只Wistar大鼠按不同脑温条件随机分为生化组(n=28)和病理组(n=32),采用改良Nagasawa局灶脑缺血再灌注模型,观察脑缺血再灌注损伤组织谷氨酸(Glu),超氧化物歧化酶(SOD)、丙二醛(MDA)的变化及光镜,电镜下的病理变化。结果:轻度高温明显加重常温脑缺血再灌注损伤组织Glu、MDA的升高(P<0.01)及SOD的下降(P<0.05),加重常温脑缺血再灌注组织病理损伤程度,亚低温的作用则相反,结论:轻度高温可能通过同时促进EAA合成,释放和氧自由基生成系统活化,造成大鼠脑缺血再灌注损组织损伤加重;亚低温可能通过同时抑制EAA合成,释放和氧自由基生成系统活化,减轻大鼠脑缺血再灌注组织损伤程度,对大鼠脑缺血再灌注损伤组织起保护作用。  相似文献   
149.
李学铭治疗IgA肾病经验   总被引:3,自引:1,他引:2  
李学铭老师诊治IgA肾病有较丰富的临床经验,笔者跟随多年,现将其诊治该病的要旨介绍如下.  相似文献   
150.
难治性气管异物的处理   总被引:1,自引:0,他引:1  
目的 探讨难治性气管异物的处理方法。方法 回顾 1994~ 2 0 0 3年 10年内收治的 12 5 8例气管异物中 ,10 9例难治性气管异物 (塑料笔帽、鸡骨头、图钉、钢珠、苍耳子球、玩具、带壳花生米、气门芯等 )的处理过程。患者年龄最小的为 8个月 ,最大的为 43岁。异物史最长达 12年。结果  89例难治性气管异物直接从支气管镜下取出 ,19例行气管切开 ,1例气门芯异物开胸取出。结论 在处理难治性气管异物时要做好充分的术前准备 ,正确判断和处理并发症。  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