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   31965篇
  免费   2725篇
  国内免费   729篇
耳鼻咽喉   82篇
儿科学   380篇
妇产科学   283篇
基础医学   1294篇
口腔科学   359篇
临床医学   2377篇
内科学   4817篇
皮肤病学   284篇
神经病学   1918篇
特种医学   322篇
外国民族医学   1篇
外科学   843篇
综合类   3813篇
现状与发展   3篇
一般理论   4篇
预防医学   3825篇
眼科学   390篇
药学   12332篇
  13篇
中国医学   1032篇
肿瘤学   1047篇
  2024年   70篇
  2023年   557篇
  2022年   784篇
  2021年   1225篇
  2020年   1127篇
  2019年   1302篇
  2018年   1352篇
  2017年   1449篇
  2016年   1251篇
  2015年   1159篇
  2014年   2164篇
  2013年   4468篇
  2012年   1916篇
  2011年   1974篇
  2010年   1677篇
  2009年   1387篇
  2008年   1326篇
  2007年   1291篇
  2006年   1141篇
  2005年   1054篇
  2004年   851篇
  2003年   733篇
  2002年   615篇
  2001年   590篇
  2000年   519篇
  1999年   405篇
  1998年   356篇
  1997年   318篇
  1996年   255篇
  1995年   236篇
  1994年   204篇
  1993年   210篇
  1992年   211篇
  1991年   227篇
  1990年   144篇
  1989年   104篇
  1988年   107篇
  1987年   85篇
  1986年   76篇
  1985年   114篇
  1984年   82篇
  1983年   46篇
  1982年   54篇
  1981年   46篇
  1980年   44篇
  1979年   25篇
  1978年   20篇
  1977年   20篇
  1976年   14篇
  1974年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Urine samples from 402 victims of ski accidents were analyzed for the presence of benzodiazepines (BZD) and alcohol. Eighty-one (20%) samples were positive for alcohol; BZD were detected in 34 (8.5%) cases. Ten of the samples (2.5%) were found to be positive for both alcohol and BZD. Subjects who were positive for either alcohol or BZD or both were older than the other persons examined. The prevalence of alcohol was significantly higher among male accident victims. BZD intake could be demonstrated to have a significant influence on the severity of injuries. Besides an increased awareness of the need for skier education regarding drug use, heightened attention of medical caregivers is warranted to inform their patients about potential accident hazards in sport activities when BZD are prescribed.  相似文献   
103.
①目的 观察适量饮酒对健康成年男性的血小板聚集功能及血浆血栓素B2 (TXB2 ) ,6 酮 前列腺素F2a(6 Keto PGF2a)的影响。②方法 将 80例健康成年男性随机分成 4组 ,分别空腹饮用矿泉水、啤酒、干红葡萄酒各 2 0 0mL ,白酒 50mL加矿泉水至 2 0 0mL .于饮前及饮后 2h分别测定血小板的聚集率及解聚率 ,并采血测定血浆TXB2 ,6 Keto PGF2a.③结果 矿泉水组饮后上述指标无变化 (t=0 .0 3~ 0 .84,P >0 .0 5) ;白酒、啤酒、红葡萄酒组饮后血小板聚集率减低 (t=8.1 2~ 2 4 .39,P <0 .0 1 ) ,解聚率升高 (t=2 8.48~ 35 .2 2 ,P <0 .0 1 ) ,血浆TXB2 降低 (t=2 5 .69~ 89.83 ,P <0 .0 1 ) ,而血浆 6 Keto PGF2a升高 (t=2 1 .0 6~ 2 3 .2 9,P <0 .0 1 )。④结论 健康成年男性适量饮酒可减低其血小板聚集功能 ,降低其血浆TXB2 ,提高其血浆 6 Keto PGF2a水平  相似文献   
104.
目的:探讨饮酒大鼠睾丸总抗氧化能力(T-AOC)、一氧化氮(NO)含量和一氧化氮合酶(NOS)活性的变化与生殖细胞凋亡的关系。方法:20只成年健康SD雄性大鼠随机均分为对照组和实验组,实验组和对照组分别用50%的乙醇溶液和蒸馏水按10 m l/kg每晚灌胃1次连续26 d(两个生精周期)后,用硝酸还原酶法测定睾丸组织中NO含量;用化学比色法测定其T-AOC和NOS活性;原位缺口末端标记(TUNEL)法检测生殖细胞凋亡指数(AI)的变化。结果:与对照组相比,实验组生殖细胞AI增加(P<0.01);睾丸组织T-AOC极显著下降(P<0.01),而NO含量明显上升(P<0.01)、NOS活性显著增强(P<0.01)。结论:大量饮酒能诱导生殖细胞凋亡增加,NOS活性增强导致NO的过量产生及T-AOC的显著下降是其重要原因。  相似文献   
105.
Age is a potential source of variation that contributes to differences between, but not within, twin pairs. In most genetic analyses of twin data, linear and other functions of age are usually removed prior to model fitting. This correction is typically applied only within twin groups of the same sex and zygosity, and no heterogeneity test of age regressions is performed. Here we include age as a variable in the model-fitting procedure and allow for tests of heterogeneity of age regressions across sex and zygosity groups. The LISREL formulation of the approach is illustrated with data collected from Australian twins on subjective impressions of drunkenness following alcohol consumption. The results indicate significant negative covariation of impressions of drunkenness with age. The data support a simple model of additive genetic and unique environmental variation. No evidence was found for sex differences in genetic or environmental components of variation.The theoretical work and data analysis described in this paper were made possible by NATO Grant 86/0823 and grants from the Belgian National Research Fund, the State University of Gent, and the Catholic University of Leuven. We are also grateful to Drs. R. Vlietinck and R. Derom for excellent organization of the successful workshop. Data collection was made possible by a grant from the Australian Associated Brewers to N.G.M. and Drs. J. G. Oakeshott, J. B. Gibson, and G. A. Starmer and by grants from the Australian National Health and Medical Research Council. The authors were supported by NIH Grants MH-40828 and AA-06781.  相似文献   
106.
目的 观察杜冷丁对产程及新生儿的影响。方法 将 16 0例初产妇随机分为观察组和对照组 ,各 80例 ,观察组在宫口开大 1.2cm时杜冷丁 10 0mg肌肉注射 ,对照组未用药。结果 第一产程用药组与对照组相比明显缩短 ,有显著差异 (P <0 .0 5 ) ,第二、三产程无差异 (P >0 .0 5 ) ,对新生儿影响、产后 2小时内出血量及新生儿体重两组无差异 (P >0 .0 5 )。结论 产程中应用杜冷丁可减轻产妇疼痛 ,缩短第一产程 ,不增加新生儿窒息 ,值得推广应用  相似文献   
107.
Background Previous reports have suggested that South Asian and white UK populations have different prevalences of intellectual disability (ID), related psychological morbidity and service use. The aim of the present study was to compare these rates among South Asian and white adults in Leicestershire, UK. Method This cross‐sectional study is comprised of two parts. The analysis of prevalence is based on data from all South Asian and white adults known to the Leicestershire Learning Disabilities Register in 1991, with population denominators being drawn from the 1991 census. The other analyses use data collected from the most recent semi‐structured home interviews, carried out between 1987 and 1998, with 206 South Asian and 2334 white adults. Results The prevalence of ID in adults in Leicestershire is 3.20 per 1000 in South Asians and 3.62 per 1000 in whites. Among adults with ID, South Asians have similar prevalences of disabilities to whites and significantly lower skill levels. South Asians show similar levels of psychological morbidity, but make significantly lower use than whites of psychiatric services, residential care and respite care. South Asians use community services as extensively as whites, but feel that they have a substantially greater unmet need, especially with regard to social services. Conclusion South Asian and white populations have similar prevalences of ID and related psychological morbidity. Culturally appropriate services for South Asian adults may need to focus on skill development and community care.  相似文献   
108.
李百川  张明 《华夏医学》2003,16(4):597-599
现代的关节镜从膀胱镜演变而来,创伤小,适用广泛。近年膝关节镜技术在半月板病变处理上有逆行全切法等新方法,交叉韧带重建、软骨移植成为研究热点;关节镜技术除应用于肩关节及其它小间隙关节,还开展治疗弹响髓等关节外应用;个性化康复锻炼提高了手术疗效。  相似文献   
109.
We have prepared a new material for embolisation: ethylene vinylacetate copolymer dissolved in polyvinyl alcohol. When in contact with blood, polyvinyl alcohol rapidly becomes a soft gel, which is accompanied by wedging of the ethylene vinylacetate copolymer. We analysed the histopathology of intra-arterial microemboli in rats, after intracarotid injection of this material. We confirmed that it was applicable to embolisation for neurosurgical treatment.  相似文献   
110.
类黄酮物质抗动脉粥样硬化作用研究进展   总被引:9,自引:0,他引:9  
人类植物性膳食成分中存在丰富的类黄酮物质,具有多种生物活性。近几年的流行病学研究和试验研究显示,类黄酮物质可以抑制动脉粥样硬化的发生与发展,从而降低心脑血管疾病的发生率和死亡率。本就类黄酮物质抗动脉粥样硬化的作用机制作一综述。  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