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   64604篇
  免费   3865篇
  国内免费   458篇
耳鼻咽喉   545篇
儿科学   1617篇
妇产科学   1520篇
基础医学   8707篇
口腔科学   1604篇
临床医学   6299篇
内科学   14942篇
皮肤病学   1103篇
神经病学   6776篇
特种医学   2184篇
外科学   8783篇
综合类   237篇
一般理论   22篇
预防医学   4343篇
眼科学   1020篇
药学   4339篇
  1篇
中国医学   150篇
肿瘤学   4735篇
  2024年   85篇
  2023年   644篇
  2022年   1325篇
  2021年   2351篇
  2020年   1440篇
  2019年   1971篇
  2018年   2295篇
  2017年   1626篇
  2016年   1842篇
  2015年   2109篇
  2014年   2884篇
  2013年   3576篇
  2012年   5392篇
  2011年   5433篇
  2010年   2817篇
  2009年   2598篇
  2008年   4299篇
  2007年   4266篇
  2006年   3797篇
  2005年   3838篇
  2004年   3314篇
  2003年   2934篇
  2002年   2685篇
  2001年   444篇
  2000年   378篇
  1999年   456篇
  1998年   522篇
  1997年   371篇
  1996年   310篇
  1995年   294篇
  1994年   260篇
  1993年   220篇
  1992年   228篇
  1991年   172篇
  1990年   150篇
  1989年   107篇
  1988年   108篇
  1987年   96篇
  1986年   97篇
  1985年   84篇
  1984年   91篇
  1983年   59篇
  1982年   76篇
  1981年   59篇
  1980年   55篇
  1979年   27篇
  1978年   33篇
  1977年   27篇
  1973年   27篇
  1970年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
143.
BACKGROUND: Genetic factors other than HLA have been reported to be associated with the outcome of organ transplantations. Because binding of FasL to its receptor Fas could play an important role in tubulitis and in the death of graft tubular epithelial cells during kidney allograft rejection, a gene polymorphism recently identified in position -671 in the promoter of the TNFRSF6 gene coding for Fas was investigated in donors. METHODS: A case-control study was performed within a cohort of non-hyperimmunized adult patients who had received cadaveric kidney transplants based on the occurrence or absence of acute cellular rejection in the first 6 months after renal transplantation. Each recipient from the acute rejection group (n = 35) was matched for age (+/- 5 years) and number of HLA-DR mismatches with two recipients within the non-acute rejection group (n = 70). RESULTS: The TNFRSF6-GG genotype was more frequent in donors in the group without rejection episodes. In contrast, patients who received a kidney from a TNFRSF6-A carrier were more likely to experience acute rejection episodes (relative risk nearly 2.1). CONCLUSION: This study suggests that donor TNFRSF6 polymorphism directly or indirectly influences acute kidney rejection episodes.  相似文献   
144.
Many medical conditions are caused or exacerbated by heavy drinking, necessitating alcohol screening and discussion in primary care practices. This is particularly true of hypertension, the most common primary diagnosis in the United States, which has been linked to the regular consumption of 3 or more standard alcoholic beverages a day. The Accelerating Alcohol Screening-Translating Research into Practice (AA-TRIP) project was designed to improve detection and management of alcohol problems in primary care patients with hypertension. Medical providers are being trained using the Practice Partner Research Network's- Translating Research into Practice (PPRNet-TRIP) quality improvement model. This includes a multi-method intervention (electronic medical records, on-site academic detailing, practice feedback reports and annual network meetings) to help practices increase adherence to clinical guidelines. Qualitative analyses of initial steps taken by nine primary care practices toward the routine implementation of alcohol screening guidelines are presented. Organizational factors and provider and patient characteristics all influenced the method and consistency of alcohol screening and intervention. Perceived time constraints, patient sensitivity to questions about alcohol, and possible stigma associated with a diagnosis of alcoholism were also relevant barriers requiring problem solving.  相似文献   
145.
Background: Percutaneous coronary intervention (PCI) is performed in patients with coronary artery disease who are undergoing major noncardiac procedures to reduce perioperative cardiac morbidity and mortality. However, the impact of this approach on postoperative outcome remains controversial.

Methods: The authors analyzed a cohort of 1,152 patients after abdominal aortic surgery in which 78 patients underwent PCI. A propensity score analysis was performed. Also, using a logistic regression model, the authors determined variables associated with a severe postoperative coronary event or a death in patients without PCI. Then, in patients with PCI, they compared the expected and observed outcome.

Results: Five variables (age > 75 yr, blood transfusion > 3 units, repeated surgery, preoperative hemodialysis, and previous cardiac failure) independently predicted (with 94% correctly classified) a severe postoperative coronary event, and five variables (age > 75 yr, repeated surgery, previously abnormal ST segment/T waves, previous hypertension, and previous cardiac failure) independently predicted (with 97% correctly classified) postoperative death. In the PCI group, the observed percentages of patients with a severe postoperative coronary event (9.0% [95% confidence interval, 4.4-17.4]) or death (5.1% [95% confidence interval, 2.0-12.5]) were not significantly different from the expected percentages (8.2 and 6.9%, respectively). When all patients were pooled together, the odds ratios of PCI were not significant. The propensity score analysis provided a similar conclusion.  相似文献   

146.
The relationships between gastric pH and Helicobacter pylori infection were studied in 37 consecutive subjects affected with nonulcer dyspepsia. Each underwent esophagogastroduodenoscopy with multiple gastric biopsies for both H. pylori and histologic assessment, and 24-hr antral pH monitoring. H. pylori was harbored by 59.5% of the subjects with whole gastric spread of infection in all but one patient. Histologic gastritis was shown in 70.3% of the subjects. H. pylori was strongly associated with gastritis, both antral nonatrophic and multifocal atrophic. The ranges of 24-hr pH values were 1.3-6.9 in the H. pylori-positive and 1.2-6.8 in the H. pylori-negative group. Differences in pH values between the two groups were not significant. Moreover, the mean percent time duration of pH above 2, 4, and 6 did not significantly differ between the two groups. Therefore, this study has shown that chronic H. pylori infection is not related to luminal gastric pH.  相似文献   
147.
Alterations in protein synthesis following exposure to and recovery from hepatotoxic doses of acetaminophen (APAP) and its analogues, 3,5-dimethyl acetaminophen (3,5-DMA) and 2,6-dimethyl acetaminophen (2,6-DMA), were investigated in primary cultures of mouse hepatocytes. The rates of protein synthesis decreased within 4 hr after administration of 10 mM APAP and occurred after significant depletion of intracellular glutathione and covalent binding of APAP to proteins, but preceded the leakage of lactate dehydrogenase into the media. The inhibition of protein synthesis was reversible only if APAP exposure did not exceed 8 hr. Electrophoretic analysis of 35S-labeled proteins by one-dimensional SDS-PAGE revealed two consistent alterations in the patterns of newly synthesized proteins. First was a progressive diminution in the de novo synthesis of a protein migrating at approximately 58 kDa (p58). This was observed with APAP (10 mM) and 3,5-DMA (5 mM) but not with 2,6-DMA (10 mM). If exposure to APAP exceeded 8 hr, the biosynthesis of this protein was not only further decreased but was also no longer detectable during the recovery period. The second major alteration was an increase in the relative rate of biosynthesis of a 32-kDa protein (p32) following exposure and recovery from APAP and 3,5-DMA but not 2,6-DMA. Exposure to heme or arsenite induced the synthesis of a protein of similar molecular weight but did not result in the inhibition of p58 biosynthesis. The fact that the reactive metabolites of both APAP and 3,5-DMA, but not 2,6-DMA, possess oxidative properties suggests that the alterations in the synthesis of p32 and p58 may be related to an oxidative component induced by these compounds.  相似文献   
148.
In the mental health service system, disputes take on various forms and exist in both clinical practice and management. Existing policy and administrative practice has favored a combination of medical and judicial/legal models to handle conflicts among consumers, mental health professionals, and others. The authors propose the addition of mediation as a third form of resolving issues, explicate some of the differences between mediation and current methods of resolving conflicts, and suggest benefits of using mediation.Noel Mazade is Executive Director, National Association of State Mental Health Program Directors Research Institute and a practicing mediator. Andrea Blanch is Director of Community Support Programs for the New York Office of Mental Health in Albany, NY.The views presented in this article are those of the authors only. Endorsement by the authors' organizational affiliations is not implied nor should it be inferred.  相似文献   
149.
150.
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