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   65585篇
  免费   5966篇
  国内免费   4913篇
耳鼻咽喉   640篇
儿科学   702篇
妇产科学   619篇
基础医学   7767篇
口腔科学   1115篇
临床医学   8628篇
内科学   9762篇
皮肤病学   600篇
神经病学   3596篇
特种医学   2526篇
外国民族医学   34篇
外科学   6897篇
综合类   11142篇
现状与发展   16篇
一般理论   1篇
预防医学   4482篇
眼科学   1883篇
药学   6869篇
  54篇
中国医学   3354篇
肿瘤学   5777篇
  2024年   213篇
  2023年   1080篇
  2022年   2729篇
  2021年   3428篇
  2020年   2518篇
  2019年   2197篇
  2018年   2311篇
  2017年   2039篇
  2016年   1946篇
  2015年   3103篇
  2014年   3725篇
  2013年   3161篇
  2012年   4957篇
  2011年   5480篇
  2010年   3526篇
  2009年   2592篇
  2008年   3295篇
  2007年   3452篇
  2006年   3352篇
  2005年   3472篇
  2004年   2216篇
  2003年   2105篇
  2002年   1760篇
  2001年   1401篇
  2000年   1576篇
  1999年   1618篇
  1998年   1080篇
  1997年   1011篇
  1996年   759篇
  1995年   708篇
  1994年   676篇
  1993年   396篇
  1992年   473篇
  1991年   426篇
  1990年   367篇
  1989年   313篇
  1988年   232篇
  1987年   227篇
  1986年   170篇
  1985年   114篇
  1984年   66篇
  1983年   59篇
  1982年   43篇
  1981年   31篇
  1980年   14篇
  1979年   23篇
  1978年   4篇
  1977年   3篇
  1975年   4篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
目的 研究利培酮临床效应的个体差异与其代谢酶细胞色素P4 5 0 2D6 (cytochromeP4 5 02D6 ,CYP2D6 )酶基因多态性的相关性。方法 对 88例符合CCMD 3精神分裂症诊断标准的患者和 96例健康对照者作病例 -对照分析。精神分裂症患者给予利培酮治疗 8周 ,用阳性和阴性症状量表 (posi tiveandnegativesymptomscale ,PANSS)评分评价利培酮疗效。采用聚合酶链反应扩增及限制性片段长度多态性 (PCR RFLP)技术对CYP2D6exonⅠ的C188T位点突变进行检测 ,分析利培酮临床效应与其主要代谢酶CYP2D6 /C188T酶基因多态性的相关性。结果 中国上海地区人群的CYP2D6 /C188T突变率(弱代谢型 )为 36 .3% ,病例组和正常对照组间基因型频率总体分布比较无显著差异 (χ2 =1.15 ,df=2 ,P >0 .0 5 ) ,两组间的等位基因频率之间比较也无显著性差异 (χ2 =0 .78,df=1,P >0 .0 5 )。进行性别及有否家族史分组后分析 ,亦无差异存在 ,且CYP2D6 /C188T突变与利培酮临床效应之间并无相关性 (χ2 =1.12 ,df=2 ;χ2 =0 .0 3,df=1,P >0 .0 5 )。结论 未发现中国人CYP2D6 /C188T多态性与利培酮临床效应的个体差异有相关性。  相似文献   
22.
阐述了AGFALR5200激光相机的工作原理、日常使用保养。  相似文献   
23.
A case of severe hemophilia A was treated by living mother-to-son splenic transplantation. The recipient was a 9-year-old boy. After splenic transplantation, the level of blood factor VIII:C was increased, and no spontaneous hemorrhage occurred. The boy was followed up for over two years. This is a case of spleen allotransplantation with the longest function in the world.
  相似文献   
24.
PharmacokineticsofintravenouslyadministeredsodiumdichloroacetateinrabbitsGuBin(顾斌);SongLing(宋岭);JiangYongpei(蒋永培);WenAidong(文...  相似文献   
25.
Inactivated whole avian influenza virus (AIV) vaccine provides protection against homologous haemagglutinin (HA) subtype virus, but poor protection against a heterologous HA virus. Moreover, it induces chickens to produce antibodies to cross-reactive antigens, especially nucleoprotein, which is limits AIV serological surveillance. In this study, a recombinant fowlpox virus co-expressing HA (H5 subtype) and NA (N1 subtype) genes of AIV was evaluated for its ability to protect chickens against intramuscular challenge with a lethal dose of highly pathogenic (HP) AIV. Susceptible chickens were also vaccinated by wing-web puncture with the parent fowlpox vaccine virus. Following challenge 4 weeks later with HPAIV, all chickens vaccinated with recombinant virus were protected, while the chickens vaccinated with either the unaltered parent fowlpox vaccine virus or unvaccinated controls experienced 100% mortality following challenge. This protection was accompanied by the high levels of specific antibody to the respective components of the recombinant vaccine. The above results showed that rFPV-HA-NA could be a potential vaccine to replace current inactivated vaccines for preventing AI.  相似文献   
26.
益气活血汤对老年肺心病心衰患者血液流变学的影响   总被引:3,自引:0,他引:3  
目的探讨益气活血汤对老年肺心病心衰患者血液流变性的影响。方法将48例肺心病心衰患者随机分为两组,均采用常规西医治疗,治疗组加用益气活血汤;观察两组治疗前后血液流变学指标变化情况。结果治疗组治疗前后比较,各项血液流变学指标改变差异有显著性,对照组治疗前后比较无统计学意义;治疗组各项指标与对照组比较差异有显著性。结论益气活血汤对肺心病心衰有改善血液流变性的作用。  相似文献   
27.
28.
29.
Postnatal development and differentiation of the rat epididymis was studied in the rat from 15 to 120 days of life using stereological techniques. Both the relative volume (volume density) and absolute volume of the epithelial, interstitial, and luminal compartments in the initial segment, caput, corpus, and cauda epididymides were determined. In all segments the volume density of the epithelial compartment increased between days 15 and 30 before falling to adult values at 45 days in the initial segment (0.476 ± 0.031), at 60 days in the caput (0.258 ± 0.028) and at 90 days in the corpus (0.245 ± 0.007) and cauda (0.140 ± 0.004). The relative volume of the interstitium decreased, whilst that of the lumen increased over the same period with adult values being achieved earlier in the proximal segments than in the distal segments. In contrast to volume fraction the absolute volume of all compartments in all segments increased from day 15 to day 90. Between 90 and 120 days the absolute volumes of compartments in the initial segment and caput showed little volume change. All compartments in the corpus and cauda showed significant increases in volume over the same period. A similar pattern of development was observed with respect to the surface area of both the luminal and basement membrane aspects of the epithelium; surface area per unit volume (surface density) in all segments reached adult values at approximately 60 days, whilst the increase in absolute area of the surfaces ceased at 90 days in the initial segment and caput and continued to 120 days in the corpus and cauda. The total length of the epididymal tubule showed the same pattern with no increase in length apparent in the initial segment and caput after 90 days. Length however continued to increase in the corpus and cauda between 90 and 120 days. Tubule and luminal diameter reached their definitive values in the initial segment on day 60 but continued to increase until day 90 in the distal segments. Epithelial height increased between 15 and 30 days in all segments; in the caput, epithelial height was greatest on day 30 before decreasing slightly; and in the corpus and cauda maximal epithelial height was observed on day 45 decreasing to stable values on day 60 and 90, respectively. All the data is consistent with a proximal to distal differentiation and development of the epididymis with growth continuing in all segments after the establishment of the definitive architecture. Growth of the distal segments continued after its cessation in the proximal segments. © 1994 Wiley-Liss, Inc.  相似文献   
30.
双语教学Powerpoint课件制作探讨   总被引:5,自引:0,他引:5  
针对Powerpoint软件在课件制作上常存在的屏幕背景与文字色彩对比不当、文字数量太多及字体太小、文字动画太多且乱、声音混杂等问题,结合实践就如何制作课件,尤其是双语教学课件,从总体布局、屏幕文字安排、背景与版式的设计、声音与动画等方面进行了探讨,并介绍了多种特殊效果的应用技巧.  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