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   62043篇
  免费   4948篇
  国内免费   170篇
耳鼻咽喉   541篇
儿科学   2314篇
妇产科学   1495篇
基础医学   8574篇
口腔科学   1335篇
临床医学   7957篇
内科学   12612篇
皮肤病学   1178篇
神经病学   6388篇
特种医学   1527篇
外科学   6239篇
综合类   590篇
一般理论   76篇
预防医学   7177篇
眼科学   1107篇
药学   3525篇
  2篇
中国医学   65篇
肿瘤学   4459篇
  2023年   470篇
  2022年   597篇
  2021年   1597篇
  2020年   1117篇
  2019年   1709篇
  2018年   1873篇
  2017年   1477篇
  2016年   1589篇
  2015年   1714篇
  2014年   2263篇
  2013年   3266篇
  2012年   4779篇
  2011年   4901篇
  2010年   2686篇
  2009年   2413篇
  2008年   4090篇
  2007年   4296篇
  2006年   4179篇
  2005年   3973篇
  2004年   3862篇
  2003年   3487篇
  2002年   3204篇
  2001年   470篇
  2000年   355篇
  1999年   412篇
  1998年   703篇
  1997年   518篇
  1996年   445篇
  1995年   440篇
  1994年   353篇
  1993年   363篇
  1992年   266篇
  1991年   213篇
  1990年   189篇
  1989年   172篇
  1988年   167篇
  1987年   130篇
  1986年   154篇
  1985年   159篇
  1984年   186篇
  1983年   183篇
  1982年   218篇
  1981年   225篇
  1980年   195篇
  1979年   95篇
  1978年   117篇
  1977年   82篇
  1976年   85篇
  1975年   71篇
  1974年   72篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
This is the third and final part of a series of articles that report the findings of a study that investigated the effects of a summer externship program on the transition into a professional role among nurses who participated in a summer nurse externship program at an acute care pediatric hospital. Specifically, this article reports the retention and recruitment benefits of a summer nurse externship program for the institution from 1998 through 2003. A total of 153 externs out of the 193 (79.0%) assumed a registered nurse position at the institution, and 77% remained in that role for 12 months. Overall, the nurse extern program for this institution appeared to be an effective recruitment and retention strategy that is on par with the institution and national data for retention and turnover data.  相似文献   
42.
Application of breast cancer risk prediction models in clinical practice.   总被引:11,自引:0,他引:11  
Breast cancer risk assessment provides an estimation of disease risk that can be used to guide management for women at all levels of risk. In addition, the likelihood that breast cancer risk is due to specific genetic susceptibility (such as BRCA1 or BRCA2 mutations) can be determined. Recent developments have reinforced the clinical importance of breast cancer risk assessment. Tamoxifen chemoprevention as well as prevention studies such as the Study of Tamoxifen and Raloxifene are available to women at increased risk of developing breast cancer. In addition, specific management strategies are now defined for BRCA1 and BRCA2 mutation carriers. Risk may be assessed as the likelihood of developing breast cancer (using risk assessment models) or as the likelihood of detecting a BRCA1 or BRCA2 mutation (using prior probability models). Each of the models has advantages and disadvantages, and all need to be interpreted in context. We review available risk assessment tools and discuss their application. As illustrated by clinical examples, optimal counseling may require the use of several models, as well as clinical judgment, to provide the most accurate and useful information to women and their families.  相似文献   
43.
Previous observational research confirms abundant variation in primary care practice. While variation is sometimes viewed as problematic, its presence may also be highly informative in uncovering ways to enhance health care delivery when it represents unique adaptations to the values and needs of people within the practice and interactions with the local community and health care system. We describe a theoretical perspective for use in developing interventions to improve care that acknowledges the uniqueness of primary care practices and encourages flexibility in the form of intervention implementation, while maintaining fidelity to its essential functions.  相似文献   
44.
Postpartum fatigue is a normal condition that most women experience. Breastfeeding is often associated in women's minds as contributing to the feeling of overall perceived fatigue, and many women indicate that they have ceased breastfeeding because of fatigue. However, the relationship between feeding choice and perceived fatigue has never been established. Two hundred and fifty-three women participated in a study examining whether perceived fatigue differed for bottle-feeding and breastfeeding women at 3 different times during the postpartum period (2-4 days, 6 weeks, and 12 weeks postpartum). Results showed no significant differences for these 2 groups, suggesting that perceived fatigue during the postpartum period is not dependent on feeding choice. Additional analyses examining other variables with a potential effect were nonsignificant. Because perceived physical fatigue does not appear to be dependent on feeding choice, women should be prepared for the feeling of perceived fatigue during the postpartum period while at the same time be reassured that feeding choice is not correlated.  相似文献   
45.
Hepatitis C virus (HCV)-specific impairments in host immunity have been described at multiple levels of the innate and adaptive response, which may lead to viral persistence in the majority of infections. Understanding of HCV-associated immune defects could lead to novel therapeutic advances. Natural killer (NK) cells, the major effector cells of the innate immune system, are functionally impaired in chronic HCV infection. It has been suggested that this phenotype is a result of virus-specific defects in antigen-presenting cells (APCs) that regulate NK cell activity, as normal NK function is restored when they are stimulated ex vivo. In this study, we used human NK cell cytotoxicity assays to evaluate the activation-induced effects of NK cells on the HCV replicon-containing hepatic cells. We found that cytokine-activated NK cells were capable of inducing an HCV-associated, perforin/granzyme-dependent lysis of human hepatoma cells and that this required direct cellular contact and was independent of MHC class I expression levels. In contrast, on removal of cytokine stimulation, NK cells failed to exert any direct cytolytic effect on replicon targets. These findings suggest an important underlying mechanism by which NK cells control HCV infection and, with appropriate understanding of HCV-associated immune defects, could lead to novel therapeutic advances.  相似文献   
46.
47.
This paper presents a case for careful consideration of theory in planning to implement evidence-based practices into clinical care. As described, theory should be tightly linked to strategic planning through careful choice or creation of an implementation framework. Strategies should be linked to specific interventions and/or intervention components to be implemented, and the choice of tools should match the interventions and overall strategy, linking back to the original theory and framework. The thesis advanced is that in most studies where there is an attempt to implement planned change in clinical processes, theory is used loosely. An example of linking theory to intervention design is presented from a Mental Health Quality Enhancement Research Initiative effort to increase appropriate use of antipsychotic medication among patients with schizophrenia in the Veterans Health Administration.  相似文献   
48.
Intraoperative MRI has recently entered the operating room as a new imaging modality. Customized visualization systems might further facilitate the use of this imaging technology. A visualization system for use in the interventional MRI has been developed, providing a virtual environment for surgical navigation using real-time images and for controlling the scanner. The visualization system has customized features for certain clinical applications. A training and testing facility has also been established. The introduction of the visualization system in the interventional MRI overcame several ambiguities and inconsistencies that were previously present, and resulted in a more transparent man-machine interface approach. A pilot study using the software to place cryoprobes in an animal liver showed promising results. Augmentation of real-time MR images with 3D rendering and customized navigation features opens new possibilities in intraoperative MRI. The described system can also be extended to other intraoperative imaging modalities.  相似文献   
49.
50.
Pharmaceutical companies currently spend over $17 million annually in New Zealand promoting their products with the aim of increasing sales and therefore profits. Although the industry has a code regulating advertising, the code is both weak and voluntary and is routinely violated. Increasingly, pharmaceutical companies are funding medical conferences, continuing medical education and clinical trials. While these activities sometimes contribute to furthering practitioners' education, often they are merely promotional exercises. The companies have also taken to promoting their products through the public media. Detailers' expenses account for over 60 per cent of all promotional spending, but their activities are not subject to any regulation. Advertisements in journals routinely leave out significant prescribing information and also violate provisions of the industry's code. Although the industry claims that the information transmitted in advertising helps promote better prescribing there is disturbing evidence that New Zealand practitioners are overly dependent on the pharmaceutical industry for information about medicines and that this dependence has led to less appropriate prescribing. Reforms to the promotional practices are unlikely to come from either the medical profession or the government. The most hopeful avenue of reform lies in the growing consumer movement, both within New Zealand and internationally.  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