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   1027178篇
  免费   66572篇
  国内免费   1343篇
耳鼻咽喉   13645篇
儿科学   27643篇
妇产科学   24695篇
基础医学   144296篇
口腔科学   28780篇
临床医学   86471篇
内科学   202500篇
皮肤病学   19692篇
神经病学   81749篇
特种医学   41050篇
外国民族医学   79篇
外科学   168489篇
综合类   18844篇
现状与发展   1篇
一般理论   234篇
预防医学   70362篇
眼科学   22280篇
药学   77555篇
  3篇
中国医学   2167篇
肿瘤学   64558篇
  2018年   19947篇
  2017年   15958篇
  2016年   18444篇
  2015年   9239篇
  2014年   12282篇
  2013年   17756篇
  2012年   27114篇
  2011年   34791篇
  2010年   22589篇
  2009年   20088篇
  2008年   34743篇
  2007年   38244篇
  2006年   26707篇
  2005年   27432篇
  2004年   27046篇
  2003年   27287篇
  2002年   25590篇
  2001年   55020篇
  2000年   57043篇
  1999年   47129篇
  1998年   10920篇
  1997年   9721篇
  1996年   9745篇
  1995年   9087篇
  1994年   8442篇
  1993年   7726篇
  1992年   35621篇
  1991年   34054篇
  1990年   32871篇
  1989年   31993篇
  1988年   29100篇
  1987年   28371篇
  1986年   26395篇
  1985年   25249篇
  1984年   17907篇
  1983年   15210篇
  1982年   7884篇
  1981年   6785篇
  1979年   15884篇
  1978年   10665篇
  1977年   9071篇
  1976年   7946篇
  1975年   8629篇
  1974年   10500篇
  1973年   9868篇
  1972年   9358篇
  1971年   8852篇
  1970年   8450篇
  1969年   7959篇
  1968年   7225篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
In this work, an improved version of a fiberoptics luminescence monitor, the prototype luminoscope II, is evaluated for in situ quantitative measurements. The instrument was developed to detect traces of luminescing organic contaminants on skin. An electronic background-nulling system was designed and incorporated into the instrument to compensate for various skin background emissions. A dose-response curve for a coal liquid spotted on mouse skin was established. The results illustrated the usefulness of the instrument for in vivo detection of organic materials on laboratory mouse skin.  相似文献   
992.
993.
994.
In a hospital-based case-referent study of 176 incident lung cancer cases, ascertained during a five-year period from two county hospitals, the role of asbestos exposure and smoking has been studied. Information on asbestos exposure was obtained from personal interviews, and allocated to four exposure categories, according to the intensity and duration of the exposure. Twenty-five percent of the cases and 10% of the referents had been moderately to heavily exposed to asbestos during their working career. A statistically significant trend in risk ratio related to the degree of exposure was observed, with a more than fourfold risk among the heavily exposed. The strongest association was found between asbestos exposure and small cell carcinoma, and the weakest association between asbestos exposure and adenocarcinoma. Very high risk ratios were observed among asbestos-exposed subjects who were heavy smokers, and the interaction observed between asbestos and smoking conformed more closely to a multiplicative model than to an additive one. The results suggest that the observed association between lung cancer and occupational exposures in this study was, to a large extent, due to asbestos exposure. Information on such exposure was missing in 90% of the medical records of these patients.  相似文献   
995.
996.
The effects of discrete bilateral ibotenic acid lesions to 3 areas of striatum were examined on a conditional visual discrimination task involving temporal frequency (SLOW vs FAST flashes) that had previously been shown to be sensitive to the effects of dorsal striatal dopamine depletion. Two of the groups, namely, those with nucleus accumbens (ACC) and lateral caudate-putamen (LCP) lesions, were very disrupted in the acquisition of the task. The nature of the respective impairments of the 2 groups was dissociable, however. The performance of the ACC group could be improved either by manipulations of stimulus duration or inter-stimulus interval, implying an attentional deficit. In contrast, the rats with lesions of the LCP were not significantly improved by any of the behavioural challenges. Their performance was characterised by a bias to respond to the SLOW discriminandum. Under conditions of non-reward, the LCP group extinguished their responding at a similar rate to control rats whereas the ACC group were very much more persistent. Lesions of the medial caudate-putamen failed to affect any index of performance significantly. These data suggest that the LCP is necessary for the acquisition of arbitrary stimulus-response rules and that damage to an equivalent area in humans, such as in Huntington's disease, may explain deficits of procedural memory. The second part of the experiment investigated the effects of ACC lesions on established performance of the schedule. The lesioned group behaved identically to the ACC group that had been lesioned prior to acquisition, both in terms of accuracy and degree of persistence in extinction, further implying the role of attentional factors and inflexibility in the lesion-induced deficit.  相似文献   
997.
998.
Within the past two decades, hospital pharmacists have become increasingly involved in providing consultation to physicians for drug management. Antibiotic use has become a complex and rapidly expanding discipline, complicated by the introduction of multiple new antimicrobial agents, each with unique features, and the pressures of prospective payment schemes. This study demonstrated that a team including a pharmacist had a positive impact on medical residents' utilization of antibiotics.  相似文献   
999.
1000.
A case of a branchial cyst with a high amylase activity of the cyst fluid was found in a 58-year-old female. The literature on branchial cysts with high amylase activity is reviewed. Amylase that showed high activity in the cystic fluid was revealed to be due to the salivary isoenzymes (S3 and S4) which migrated more to the anodic side on electrophoresis.  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