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   15321篇
  免费   1309篇
  国内免费   279篇
耳鼻咽喉   56篇
儿科学   411篇
妇产科学   222篇
基础医学   1763篇
口腔科学   228篇
临床医学   2185篇
内科学   1917篇
皮肤病学   117篇
神经病学   951篇
特种医学   244篇
外国民族医学   3篇
外科学   684篇
综合类   1905篇
现状与发展   1篇
一般理论   1篇
预防医学   3816篇
眼科学   69篇
药学   1116篇
  15篇
中国医学   628篇
肿瘤学   577篇
  2024年   21篇
  2023年   267篇
  2022年   421篇
  2021年   672篇
  2020年   660篇
  2019年   619篇
  2018年   583篇
  2017年   571篇
  2016年   568篇
  2015年   543篇
  2014年   1208篇
  2013年   1310篇
  2012年   983篇
  2011年   1128篇
  2010年   888篇
  2009年   746篇
  2008年   704篇
  2007年   684篇
  2006年   556篇
  2005年   491篇
  2004年   418篇
  2003年   369篇
  2002年   266篇
  2001年   217篇
  2000年   209篇
  1999年   170篇
  1998年   120篇
  1997年   166篇
  1996年   117篇
  1995年   121篇
  1994年   117篇
  1993年   73篇
  1992年   84篇
  1991年   84篇
  1990年   60篇
  1989年   56篇
  1988年   41篇
  1987年   52篇
  1986年   36篇
  1985年   72篇
  1984年   80篇
  1983年   48篇
  1982年   50篇
  1981年   30篇
  1980年   50篇
  1979年   31篇
  1978年   31篇
  1976年   20篇
  1975年   17篇
  1973年   17篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
Although the exact burden of disease caused by methicillin-resistant Staphylococcus aureus (MRSA) remains largely unknown, most experts agree that MRSA infections are an important clinical and public health problem. Thousands of reports have been published during the last four decades concerning epidemiological and microbiological aspects of MRSA, but uncertainty remains about the best approach to prevent and control this worldwide plague, especially endemic MRSA. Epidemiological methods, e.g., risk scores for targeted screening upon admission, rapid molecular tests and pre-emptive isolation of high-risk patients, new decontamination regimens and restriction of certain antibiotic classes, are all promising approaches that may decrease MRSA cross-transmission; however, further evidence is needed before these strategies can be implemented on a wide scale. Control of community MRSA is an additional challenge for the future, requiring improved surveillance and contact tracing, as well as education and treatment of both infected cases and colonised contacts. This review summarises recent advances and studies that address these issues. Overall, it seems that there is no level of MRSA prevalence for which active control measures are no longer warranted.  相似文献   
42.
Development of a disease screening biomarker involves several phases. In phase 2 its sensitivity and specificity is compared with established thresholds for minimally acceptable performance. Since we anticipate that most candidate markers will not prove to be useful and availability of specimens and funding is limited, early termination of a study is appropriate, if accumulating data indicate that the marker is inadequate. Yet, for markers that complete phase 2, we seek estimates of sensitivity and specificity to proceed with the design of subsequent phase 3 studies. We suggest early stopping criteria and estimation procedures that adjust for bias caused by the early termination option. An important aspect of our approach is to focus on properties of estimates conditional on reaching full study enrollment. We propose the conditional‐UMVUE and contrast it with other estimates, including naïve estimators, the well‐studied unconditional‐UMVUE and the mean and median Whitehead‐adjusted estimators. The conditional‐UMVUE appears to be a very good choice. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
43.
AIMS: The efficacy of three education programmes for Type 2 diabetic patients was tested in a randomized trial. A didactic-oriented training programme (treatment A) was compared with a self-management-oriented programme delivered in group sessions (treatment B). The latter programme was compared with a more individualized approach (treatment C). METHODS: One hundred and eighty-one Type 2 diabetic patients (age 55.6 +/- 6.3 years, diabetes duration 6.6 +/- 6.2 years, HbA(1c) 7.8 +/- 1.6%, female 49.7%) took part. Efficacy was assessed 3 months (t1) after baseline (t0) and at a follow-up 15 months (t2) after baseline. RESULTS: The fall in HbA(1c) in treatment B at t1 was sustained at t2 (t0 8.1 +/- 1.8%, t1 7.3 +/- 1.7%, t2 7.4 +/- 1.9%). In treatment A, HbA(1c) was unchanged throughout (t0 7.6 +/- 1.5%, t1 7.5 +/- 1.3%, t2 7.7 +/- 1.7%; treatment A vs. treatment B; P < 0.05). With the more individualized approach of treatment C, there was a fall in HbA(1c) at t1, but this was not sustained at t2 (t0 7.8 +/- 1.6%, t1 7.1 +/- 1.3%, t2 7.6 +/- 1.6%; treatment B vs. treatment C; P = 0.73). There were also significant benefits in treatment B subjects compared with treatment A in further medical (body mass index and fasting blood glucose), psychological (control, irritability and hunger dependency of eating behaviour, and trait anxiety) and behavioural (exercise) variables. There were no significant benefits of the more individualized treatment C compared with group treatment B. No significant differences were found regarding triglyceride levels, high-density lipoprotein, diabetes-related knowledge, negative well-being, urine or blood glucose levels or foot care. CONCLUSION: Self-management training had a significantly higher medium-term efficacy than didactic diabetes education. The group sessions were more effective than a more individualized approach.  相似文献   
44.
通过溴化聚苯醚和格利雅试剂反应,将不饱和基团烯丙基引入聚苯醚中实现其热固性改性,由^1H-NMR和FTIR进行结构表征。确定了烯丙化聚苯醚的固化工艺,并对其固化产物性能进行测试。结果表明:按合成新工艺制备的热固性聚苯醚,其固化产物具有优异的介电性能(低介电常数、低介电损耗因子),良好的耐溶剂性能和低吸湿性。  相似文献   
45.
中国尖音库蚊组的分类志要   总被引:3,自引:0,他引:3  
尖音库蚊类群与医学关系密切,但分类鉴定时有混淆。本文系统报告我国尖音库蚊组的组下分类,将已知的8种和2亚种,根据雄蚊尾器特征,分为三个亚组,即尖音库蚊亚组、迷走库蚊亚组和希氏库蚊亚组。并附有种的鉴别特征和检索。  相似文献   
46.
Students teaching students: a medical school peer tutorial programme   总被引:1,自引:0,他引:1  
A peer tutorial programme which is available to all first- and second-year medical students has been in operation at Case Western Reserve University School of Medicine since 1972. A retrospective study of the classes of 1982, 1983 and 1984 was undertaken to assess the participation levels in the tutorial programme and to compare the participation level to available performance parameters. The analysis revealed that 54% of the first-year classes and 22% of the second-year classes participated in the peer tutorial programme. X2 analysis of the data demonstrated that the relationship between participation in the tutorial programme and performance on examinations reached statistical significance. The results suggested that an open peer tutorial programme responded to the needs, both cognitive and affective, of medical students.  相似文献   
47.
细胞标记用大粒径羧化彩色高分子微球的研制   总被引:1,自引:0,他引:1  
赵小宁  刘有初 《医学争鸣》1996,17(4):245-247
制备一种普通光学显微镜下可见的细胞标记用大粒径彩色高分子微球。以苯乙烯及丙烯酰胺为原料,在体系中加入电解质,有机溶剂及油溶性染料,采用无乳化剂乳液聚合法制备彩色高分子微球,并通过酰肼化和羧化两步反应在微球表现衍生出羧基。  相似文献   
48.
沙市城区连续10年应用微生物制剂控制蚊虫的效果评价   总被引:6,自引:0,他引:6  
目的:观察10年来主要应用苏云金杆菌以色列变种地方株(B.t-187)控制蚊虫的效果。方法:按WHO推荐的方法,在实验室进行生物测定,以确定B.t-187乳剂使用浓度,然后进行现场灭蚊效果观察。结果:使用效价为380~460国际单位,剂量为1~2ml/m2的B.t-187乳剂能有效控制蚊约和成蚊密度,成蚊平均相对叮咬密度比处理前下降89.4%,并降低了蚊虫的季节性高峰。结论:该生物制剂对按蚊、库蚊、伊蚊幼虫的毒杀效果颇佳,蚊幼尚无产生抗性的迹象。  相似文献   
49.
Critical Incident Stress Debriefings have become an intervention method used in various cultures, countries and groups following critical incidents. Although the structure of such meetings has been adequately described, utilization of the group processes involved has received less attention. A model, process debriefing (PD), based on experiences from Europe, is presented. Some differences between the current CISD process in the United States and the Europe based model are outlined. Various factors that impact the process of debriefings are discussed with a special emphasis on leadership, and implications of these group process variables for psychological debriefing are presented. It is emphasized that the continued exploration and discussion of process issues is critical to advance the understanding of the critical elements of debriefing.  相似文献   
50.
目的:观察残杀威对德国小蠊的药效。方法:采用果酱瓶药膜法和现场试验评价效果。结果残杀威对德国小蠊敏感品系的平均KT50为13.86min,现场品系8个调查点的KT50为11.25—38.02min,对抗氯菊酯品系KT50为16.06-23.37min,72h死亡率均为100%;现场试验,4周后的杀灭率仍达90.58%。结论:残杀威对德国小蠊现场品系为一般击倒;对抗氯菊酯品系尚未形成交互抗性,其水乳剂防制舰艇蜚蠊效果满意。  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