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   76556篇
  免费   6938篇
  国内免费   1694篇
耳鼻咽喉   832篇
儿科学   1810篇
妇产科学   1241篇
基础医学   7718篇
口腔科学   1503篇
临床医学   9366篇
内科学   10964篇
皮肤病学   1026篇
神经病学   5338篇
特种医学   2865篇
外国民族医学   4篇
外科学   9538篇
综合类   8989篇
现状与发展   8篇
一般理论   34篇
预防医学   8523篇
眼科学   1627篇
药学   6851篇
  33篇
中国医学   3033篇
肿瘤学   3885篇
  2023年   468篇
  2022年   1179篇
  2021年   1685篇
  2020年   1404篇
  2019年   1073篇
  2018年   1186篇
  2017年   1334篇
  2016年   1190篇
  2015年   1788篇
  2014年   2450篇
  2013年   3375篇
  2012年   4795篇
  2011年   4947篇
  2010年   3926篇
  2009年   3546篇
  2008年   4396篇
  2007年   4451篇
  2006年   4058篇
  2005年   3560篇
  2004年   2980篇
  2003年   2641篇
  2002年   2421篇
  2001年   2216篇
  2000年   2074篇
  1999年   1505篇
  1998年   548篇
  1997年   517篇
  1996年   499篇
  1995年   471篇
  1994年   426篇
  1992年   1166篇
  1991年   1174篇
  1990年   1096篇
  1989年   1087篇
  1988年   906篇
  1987年   1028篇
  1986年   954篇
  1985年   958篇
  1984年   760篇
  1983年   621篇
  1982年   396篇
  1980年   368篇
  1979年   699篇
  1978年   522篇
  1977年   444篇
  1976年   459篇
  1975年   395篇
  1974年   520篇
  1973年   455篇
  1972年   383篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
OBJECTIVE: This article 1) provides an overview of formal Health Sciences Teaching Scholars Programs as presented in medical education literature and 2) presents information about an innovative multidiscipline Teaching Scholars Program. METHOD: Health Sciences Teaching Scholars Programs and similar programs were reviewed in the medical education literature to identify similar and dissimilar characteristics. The WVU Teaching Scholars Program highlighted in this article is presented with a discussion of goals, objectives, target audiences, course length, session frequency, program topics, learning methods, and assessments of the programs. A summary of the WVU Teaching Scholars Program and two Teaching Scholars Programs at McGill University and the University of Toronto were presented at the Association for American Medical Colleges (AAMC) annual meeting in 2006 for input from the general medical education audience. RESULTS: Comparisons of Health Sciences Teaching Scholars Programs reveal that successful programs are uniquely shaped by their educational environments. Scholars report that they value learning new teaching methods and improving their educational careers. CONCLUSION: Teaching Scholars Programs are valuable for the development of enhancing both teaching and scholarship in Health Sciences Programs and must adapt to the uniqueness of their respective educational environments and must continue to nurture scholars beyond graduation.  相似文献   
24.
The purpose of this study was to provide, in a large number of patients, comprehensive Doppler echocardiographic assessment of normal St Jude Medical mitral valve prosthesis function using Doppler-derived hemodynamic variables, including the mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio and prosthesis performance index. The pressure half-time was less than 130 milliseconds in all patients, and all but one patient had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2. There was a significant (P < .001) negative correlation between the prosthesis performance index and prosthesis size. This negative correlation suggests that there is more efficient use of the in vitro geometric orifice area with smaller prostheses.  相似文献   
25.
Serum protein electrophoresis (SPEP) data obtained at diagnosis were available for 98 of 342 patients with chronic lymphocytic leukemia (CLL) identified in a population-based case-control epidemiologic study. Patients tested with SPEP at diagnosis were significantly younger, more likely to have lymphadenopathy, and more likely to have had their conditions diagnosed at a university hospital than those not tested. Four categories of electrophoretic patterns were identified: normal (N = 56), hypogammaglobulinemia (N = 28), hypergammaglobulinemia (N = 11), and monoclonal gammopathy (N = 3). A higher proportion of those with hypergammaglobulinemia were black, and patients with hypergammaglobulinemia and monoclonal gammopathy were more likely to die within the first year following diagnosis than patients in the other SPEP groups. No association was found, however, between SPEP pattern and a clinical staging classification for CLL. These findings suggest that SPEP may be a useful adjunct in categorizing possible subtypes of CLL and developing future clinical staging classifications.  相似文献   
26.
27.
Ivalon (polyvinyl alcohol) is a commonly used embolic agent, generally considered to be permanent. In a patient with the carcinoid syndrome, embolization of hepatic metastases with Ivalon failed to produce permanent occlusion, and recurrent tumor was supplied by many of the same small arteries identified on the original arteriogram. Occasionally, Ivalon may have only a temporary occlusive effect. A possible explanation for this phenomenon is proposed.  相似文献   
28.
R J Barohn  R G Miller  R C Griggs 《Neurology》1991,41(9):1365-1370
We describe five new cases of autosomal recessive distal dystrophy (Miyoshi myopathy) and emphasize the distinctive clinical and laboratory features of this unusual muscular dystrophy. Symptoms began at age 15 to 25, the gastrocnemius muscles were selectively involved, and creatine kinase was elevated more than 10 times normal. The EMG showed abundant brief motor units with numerous fibrillations. Dystrophic features without vacuoles were best seen in the biceps femoris muscle. Asymptomatic creatine kinase elevation was present years prior to the development of weakness. The disorder appears to be inherited in an autosomal recessive pattern. Miyoshi myopathy can be distinguished from other distal muscular dystrophies. We propose a new classification for the distal muscular dystrophies.  相似文献   
29.
Osteoporosis is a common disease with a strong genetic component characterized by reduced bone mass and an increased risk of fragility fractures. Bone mineral density (BMD) is the most important determinant of osteoporotic fracture risk, but the genes responsible for BMD regulation and fracture are incompletely defined. To enable multi-center studies to examine the genetic influences on BMD there is a requirement to standardize measurements across different manufacturers of bone densitometers, different versions of machines and different normative ranges. This paper describes a method developed to allow near-identical subjects with low age-adjusted BMD (based on Z-scores) to be recruited in 17 centers using 27 different densitometers. Cross-calibration was based on measurements using a European spine phantom circulated to all centers and measured ten times on each individual machine. From theses values an individual exponential curve, based on nominal versus observed BMD, was derived for each machine. As expected, there were large and significant variations in nominal BMD values, not only between scanners from different manufacturers but also between different versions of scanners from the same manufacturer. Hologic scanners tended to underestimate the nominal BMD, while Lunar scanners overestimated the value. Norland scanners gave mixed values over estimating BMD at the lower nominal value (0.5 g/cm2) while underestimating the value at the higher value (1.5 g/cm2). The validity of the exponential equations was tested using hip and spine measurements on 991 non-proband women from a familial osteoporosis study (FAMOS). After cross-calibration there was a considerable reduction in variation between machines. This observation, coupled with the absence of a similar reduction in variation attributable to a linear regression on age, demonstrated the validity of the cross-calibration approach. Use of the cross-calibration curves along with a standard normative range (in the case of this study, the Hologic normative range) allowed age-specific Z-scores to be used as an inclusion criterion in this genetic study, a method that will be useful for other trials where age-specific BMD inclusion criteria are required.  相似文献   
30.
Three children with malignant primary CNS tumors treated with craniospinal radiotherapy developed intraparenchymal hemorrhages a median of 5 years following therapy in sites distant from the primary tumor. Radical surgical procedures disclosed fresh and old hematoma, gliosis, and necrosis in all 3 patients and an aggregation of abnormal microscopic blood vessels in two. No tumor was found. All 3 patients remain in long-term (greater than 10 years) continuous remission.  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