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   83306篇
  免费   7098篇
  国内免费   2899篇
耳鼻咽喉   1003篇
儿科学   1210篇
妇产科学   1647篇
基础医学   11938篇
口腔科学   1940篇
临床医学   7684篇
内科学   15247篇
皮肤病学   1728篇
神经病学   5843篇
特种医学   2710篇
外国民族医学   19篇
外科学   11319篇
综合类   7917篇
现状与发展   5篇
一般理论   24篇
预防医学   4816篇
眼科学   2507篇
药学   7181篇
  19篇
中国医学   1822篇
肿瘤学   6724篇
  2023年   624篇
  2022年   1228篇
  2021年   1914篇
  2020年   1362篇
  2019年   1571篇
  2018年   2180篇
  2017年   1803篇
  2016年   1794篇
  2015年   2183篇
  2014年   2806篇
  2013年   3039篇
  2012年   4413篇
  2011年   4396篇
  2010年   2574篇
  2009年   2348篇
  2008年   3481篇
  2007年   3604篇
  2006年   3436篇
  2005年   3120篇
  2004年   2536篇
  2003年   2342篇
  2002年   2168篇
  2001年   5353篇
  2000年   5264篇
  1999年   4632篇
  1998年   1779篇
  1997年   1340篇
  1996年   876篇
  1995年   787篇
  1994年   679篇
  1993年   578篇
  1992年   2220篇
  1991年   1949篇
  1990年   1792篇
  1989年   1733篇
  1988年   1505篇
  1987年   1381篇
  1986年   1250篇
  1985年   1044篇
  1984年   688篇
  1983年   536篇
  1982年   297篇
  1981年   233篇
  1980年   182篇
  1979年   352篇
  1978年   128篇
  1977年   113篇
  1974年   140篇
  1973年   155篇
  1972年   134篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
新型纳米根管充填材料对成骨细胞生长的影响   总被引:2,自引:0,他引:2  
通过体外培养的成骨细胞,采用二甲基噻唑二苯基四唑溴盐比色法和流式细胞术对新型纳米根管充填材料(nHA-PA66)作用下的成骨细胞生长情况的变化进行研究,评价其对成骨细胞生长的影响。以该材料的细胞培养基浸提液作用于实验组细胞,对照组采用培养基本身。实验组和对照组成骨细胞的生长情况和细胞周期无显著性差异,表明该新型纳米材料对成骨细胞的生长和细胞周期无不良影响。提示新型纳米根管充填材料的成骨细胞相容性较好,具有用作根充材料的基础。  相似文献   
92.
甲氧苄氨嘧啶—PVP共沉淀物的研究   总被引:1,自引:0,他引:1  
本工作用差示扫描量热法(DSC)研究甲氧苄氨嘧啶与PVP溶剂法制备的共沉淀物,表明已不存在甲氧苄氨嘧啶晶体。用x射线衍射法研究了1:12共沉淀物,证明无甲氧苄氨嘧啶的晶体衍射峰。经分光光度法测定结果,1:12共沉淀物比原药的溶解度大28.3倍。  相似文献   
93.
94.
Experience in the treatment of 30 cases with gas gangrene from war wounds   总被引:1,自引:0,他引:1  
Z Y Li  X L Wang  X S Wang 《中华外科杂志》1986,24(10):580-1, 637
  相似文献   
95.
When blood flow through the internal and external carotid arteries is completely interrupted by ipsilateral common carotid artery occlusion, the arterial orbital circulation may be more compromised than the brain supply. We studied a pure and extreme example of this situation in a patient who presented with acute orbital infarction, but no cerebral ischemia on clinical, CT and single-photon emission computerized tomography (SPECT) grounds. Ipsilateral blindness corresponded to retinal, choroidal and optic nerve infarction. The pattern of ophthalmoplegia, with relative sparing of adduction, was more compatible with a muscle than a nerve dysfunction, but a reactive dilated pupil, corneal anesthesia, and orbital pain suggested that the intraorbital branches of the ocular motor nerves and ophthalmic division of the trigeminal nerve were not spared. In addition, signs of widespread ocular ischemia were present. Sequential examinations documented the evolution pattern over 1 year. The absence of an orbital collateral supply from the contralateral external carotid and muscular cervical arteries systems, which contrasted with an adequate middle cerebral artery supply via the contralateral internal carotid artery, may explain this isolated and complete form of orbital ischemia due to common carotid artery occlusion.  相似文献   
96.
An epidemiological study on the incidence and prevalence of Parkinson's disease (PD) was carried out in 29 provinces, cities and autonomous regions in this country in 1986. The survey was conducted in 117 areas, and 566 patients with PD were found among 3,869,162 persons examined, giving a point prevalence for men and women of 16.9/10(5) and 12.4/10(5), with the highest prevalence after the fifth decade of age. The disease was most prevalent in the southern part of China, especially in Hunan and Guangxi provinces. The incidence was 1.5/10(5)/yr in 1986. Both the prevalence and incidence of PD in China are lower than those in the white race and Japanese.
  相似文献   
97.
98.
Delta hepatitis virus infection in China   总被引:1,自引:0,他引:1  
To assess the prevalence, epidemiological features and prognostic implications of hepatitis D (Delta) in Sichuan Province, The People's Republic of China, 649 sera (515 from HBsAg positive patients and 134 from HBsAg negative subjects) were tested by radioimmunoassay (RIA) for antibody to the hepatitis D virus (anti-HD). Forty-seven sera (7.2%) showed some degree of reactivity. Serial dilutions of these sera indicated that prozoning was not responsible for the equivocal results. Thirty-four of the 47 sera were submitted under code to a second laboratory for independent analysis. According to those results anti-HD antibodies were detected in four of these sera. The overall prevalence of anti-HD in the HBsAg positive patients therefore was 0.8% (4/515). On the basis of clinical, biochemical and histological data 427 HBsAg positive sera were further divided into acute Type B hepatitis, chronic Type B hepatitis, healthy carrier state and hepatocellular carcinoma (HCC) subgroups. Two of 65 (3.1%) anti-HD positive sera belonged to the acute Type B hepatitis group; one of 104 (0.9%), the chronic Type B hepatitis group and one of 246 (0.4%), the healthy carrier group. No antibody was detected in sera from 12 HBsAg positive HCC patients. All HBsAg negative patients were negative for anti-HD antibody. The results of this study indicate that despite a high prevalence of hepatitis B virus infection, positive serology for delta virus is uncommon in Sichuan Province, The People's Republic of China.  相似文献   
99.
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