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   13303篇
  免费   2776篇
  国内免费   143篇
耳鼻咽喉   388篇
儿科学   347篇
妇产科学   445篇
基础医学   876篇
口腔科学   313篇
临床医学   3213篇
内科学   2761篇
皮肤病学   373篇
神经病学   1128篇
特种医学   552篇
外科学   1681篇
综合类   411篇
现状与发展   2篇
一般理论   2篇
预防医学   2014篇
眼科学   156篇
药学   396篇
  1篇
中国医学   106篇
肿瘤学   1057篇
  2024年   81篇
  2023年   428篇
  2022年   153篇
  2021年   330篇
  2020年   540篇
  2019年   237篇
  2018年   658篇
  2017年   665篇
  2016年   691篇
  2015年   786篇
  2014年   843篇
  2013年   1196篇
  2012年   629篇
  2011年   561篇
  2010年   655篇
  2009年   717篇
  2008年   496篇
  2007年   466篇
  2006年   495篇
  2005年   410篇
  2004年   338篇
  2003年   288篇
  2002年   255篇
  2001年   278篇
  2000年   189篇
  1999年   206篇
  1998年   315篇
  1997年   327篇
  1996年   353篇
  1995年   275篇
  1994年   198篇
  1993年   143篇
  1992年   149篇
  1991年   137篇
  1990年   134篇
  1989年   161篇
  1988年   127篇
  1987年   103篇
  1986年   100篇
  1985年   95篇
  1984年   79篇
  1983年   67篇
  1982年   57篇
  1981年   72篇
  1980年   47篇
  1979年   50篇
  1978年   43篇
  1977年   36篇
  1976年   31篇
  1973年   38篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
OBEJCTIVE: Although cost-effectiveness analyses (CEAs) have been advocated as a tool to critically appraise the value of health expenditures, it has been widely hoped that they might also help contain health care costs. To determine how often they discourage additional expenditures, we reviewed the conclusions of recently published CEAs. DATA SOURCES: A search of the Abridged Index Medicus (a subset of MEDLINE designed to afford rapid access to the literature of “immediate interest” to the practicing physician) between 1990 and 1996. STUDY SELECTION: We only included articles that reported an explicit cost-effectiveness (CE) ratio (a cost for some given health effect) in the abstract. DATA ABSTRACTION: From each abstract, we collected the value for the incremental CE ratio and the measure of health effect (life-years, quality-adjusted life-years [QALYs], other). We then categorized the authors’ conclusion into one of three categories: supports strategy requiring additional expenditure, no firm conclusion, and supports low-cost alternative. Finally, we obtained the article and collected information on funding source. DATA SYNTHESIS: Among the 109 eligible articles, the authors’ conclusion supported strategies requiring additional expenditure in 58 (53%) and supported the low-cost alternative in 28 (26%). We then focused on the 65 articles reporting either life-years or QALYs. Cost-effectiveness ratios ranged from $400 to $166,000 (per life-year or QALY) in the 39 articles (60%) in which authors supported additional expenditure, and ranged from $61,500 to $11,600,000 in the 13 articles (20%) in which authors supported the low-cost alternative. Despite identifying similar CE ratios, authors arrived at different conclusions in the overlapping range ($61,500 to $166,000). Of the 10 articles acknowledging industry funding, 9 supported a strategy requiring additional expenditure (p=.01 as compared with those without such funding). CONCLUSIONS: Authors of CEAs are more likely to support strategies requiring additional expenditure than the low-cost alternative. There is no obvious consensus about how small the CE ratio should be to warrant additional expenditure. Finally, concerns about funding source seem to be warranted.  相似文献   
992.
993.
Genetic characterization of human tumors promises new insights of biological importance and clinical relevance. We have found that two solid tumors, peripheral neuroepithelioma and Ewing's sarcoma of bone, which share a common cytogenetic rearrangement, are characterized by an indistinguishable and highly reproducible pattern of protooncogene expression. c-myc, N-myc, c-myb, and c-mil/raf-1 are all expressed at similar levels in these tumors. c-fes and c-sis expression was not detected in any specimens of either tumor. In contrast, the protooncogene c-ets-1, located near the breakpoint of the chromosomal translocation in these tumors, is variable in its expression. We also detected high levels of choline acetyltransferase in these tumors, which suggests a common neural origin. Since it is likely that the clinical behavior and therapeutic responsiveness of tumors relate closely to their biological and genetic features, the pattern of protooncogene expression of individual tumors may provide a novel basis for their characterization.  相似文献   
994.
995.
This paper is a preliminary study, part of a larger project which is endeavouring to ascertain the views of both users of mental health services and those of mental health branch students as to their perceived and desired role of the mental health nurse Four groups of users (n = 28) and four groups of students (n=44) were contacted, and recorded group discussions took place in gaining qualitative data that would feed into the main body of research The views expressed by both users and students are interestingly convergent, but much concern was expressed as to the needed changes in the provision of the service and the danger for students on qualifying to become quickly incorporated into the prevailing dominant culture  相似文献   
996.
997.
998.
The effects of signposts and a ward orientation training programme has been examined with six patients from a male psychogeriatric ward. The results indicate that improved ward orientation can be achieved in such patients, by the use of both signposts themselves and specific training involving the use of signposts. Implications for psychogeriatric rehabilitation nursing are discussed  相似文献   
999.
1000.
Development of the small intestine is well underway by birth, but it contributes a meager 1.4% (0.07 g) to total body weight. At 25 g (five times the birth weight), it has more than doubled in length (from 20 to 45 cm), is about nine times as heavy, and represents 2.4% (0.6 g) of the body weight. During adolescence, the small intestine undergoes rapid gains until it reaches 75% of its adult length (80 cm), and attains a maximum percentage of nearly 5.0% (3.0 g) of the body weight (60 g). By 125 g, it is nearly fully developed: 95 cm in length, 5 g in weight, and 4% of the body weight. From this point, it only lengthens 10–20 cm and increases 1–2 g in weight. However, the percent of intestine to body weight continues to decrease throughout adulthood to reach only 1.4% (500 g), which was the percentage at birth. Regression formulas show that in the adult rat, the small intestine lengthens 5 cm and gains 0.5 g for each 100-g increase in body weight. Variation within each of the intestinal values measured was considerable but correlated positively with the body weight. Tissue water content was greatest in the duodenum, and varied according to both site and age.Supported in part by Research Grant AM02534 from the National Institutes of Health.The author wishes to acknowledge the valuable guidance of Drs. Harold P. Schedl, MD, PhD, and M. Kabir Younoszai, MD; and the technical assistance of Helen D. Wilson.  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