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   126148篇
  免费   9119篇
  国内免费   221篇
耳鼻咽喉   1135篇
儿科学   3491篇
妇产科学   2608篇
基础医学   19701篇
口腔科学   3303篇
临床医学   10643篇
内科学   25615篇
皮肤病学   2180篇
神经病学   12135篇
特种医学   5264篇
外国民族医学   9篇
外科学   15781篇
综合类   545篇
现状与发展   1篇
一般理论   106篇
预防医学   14410篇
眼科学   1968篇
药学   7393篇
  1篇
中国医学   242篇
肿瘤学   8957篇
  2023年   538篇
  2022年   898篇
  2021年   1955篇
  2020年   1415篇
  2019年   2064篇
  2018年   2597篇
  2017年   2202篇
  2016年   2393篇
  2015年   2676篇
  2014年   3681篇
  2013年   4795篇
  2012年   7384篇
  2011年   7452篇
  2010年   3873篇
  2009年   4055篇
  2008年   6604篇
  2007年   6822篇
  2006年   6556篇
  2005年   6217篇
  2004年   5292篇
  2003年   5014篇
  2002年   4558篇
  2001年   4455篇
  2000年   4396篇
  1999年   3914篇
  1998年   1621篇
  1997年   1334篇
  1996年   1426篇
  1995年   1163篇
  1994年   1090篇
  1993年   977篇
  1992年   2675篇
  1991年   2408篇
  1990年   2281篇
  1989年   2142篇
  1988年   1969篇
  1987年   1719篇
  1986年   1631篇
  1985年   1565篇
  1984年   1118篇
  1983年   970篇
  1982年   524篇
  1981年   460篇
  1980年   401篇
  1979年   859篇
  1978年   522篇
  1977年   432篇
  1974年   417篇
  1973年   411篇
  1972年   366篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
This paper presents a method for calculating stage line diagrams, a novel type of reference diagram useful for tracking developmental processes over time. Potential fields of applications include: dentistry (tooth eruption), oncology (tumor grading, cancer staging), virology (HIV infection and disease staging), psychology (stages of cognitive development), human development (pubertal stages) and chronic diseases (stages of dementia). Transition probabilities between successive stages are modeled as smoothly varying functions of age. Age‐conditional references are calculated from the modeled probabilities by the mid‐P value. It is possible to eliminate the influence of age by calculating standard deviation scores (SDS). The method is applied to the empirical data to produce reference charts on secondary sexual maturation. The mean of the empirical SDS in the reference population is close to zero, whereas the variance depends on age. The stage line diagram provides quick insight into both status (in SDS) and tempo (in SDS/year) of development of an individual child. Other measures (e.g. height SDS, body mass index SDS) from the same child can be added to the chart. Diagrams for sexual maturation are available as a web application at http://vps.stefvanbuuren.nl/puberty . The stage line diagram expresses status and tempo of discrete changes on a continuous scale. Wider application of these measures scores opens up new analytic possibilities. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
75.
Introduction Choroid plexus cysts can lead to isolation of the lateral ventricles and distension of the third ventricle. We present an ultrasonographic video documentation of an infant with variably shaped and localized choroid plexus cyst of the third ventricle. Case report An infant had periods of increased intracranial pressure with changing dilatation of the first to third ventricle. Cerebral ultrasonography of the not crying boy demonstrated a choroid plexus cyst limply hanging down from the roof of the third ventricle to the beginning of the aqueduct of Sylvius. During crying, the cyst prolapsed from the third into left lateral ventricle and was strangled by the foramen of Monro. Endoscopic cyst fenestration and third ventriculostomy continuously solved the problem of intermittent hydrocephalus occlusus. Conclusion Depending not only on localization and size but also on cyst form and cerebrospinal fluid pressure, a single choroid plexus cyst can cause various obstructions of cerebrospinal fluid pathways.  相似文献   
76.
77.
78.
OBJECTIVE: The purpose of this study was to evaluate the potential benefit of an ultrasonic device in apical surgery on the outcome of treatment. STUDY DESIGN: A randomized prospective design was used in a standardized treatment protocol. Patients were allocated to treatment with an ultrasonic device (P-Max Newtron) or treatment with a bur in an otherwise similar protocol. One year after treatment the results were evaluated by 2 oral and maxillofacial surgeons who were blinded for the therapy. RESULTS: Out of a total group of 399 patients who were included in the study, adequate follow-up could be obtained in 290 patients. The overall success rate in the ultrasonic group was 80.5% and in the group treated with a bur 70.9% (P = .056). In molars, the difference in success rate was significant (P = .02). CONCLUSION: The use of an ultrasonic device in apical surgery improved the outcome of treatment. In molars this effect was significant.  相似文献   
79.
HYPOTHESIS: Based on recent findings on the association between vascular risk factors and hippocampal atrophy, we hypothesized that hypertension and diabetes mellitus (DM) are associated with medial temporal lobe atrophy (MTA) in subjects without disability, independent of the severity of white matter hyperintensities. METHODS: In the Leukoaraiosis And DISability in the elderly (LADIS) study, we investigated the relationships between DM, hypertension, blood pressure and MTA in 582 subjects, stratified by white matter hyperintensity severity, using multinomial logistic regression. MTA was visually scored for the left and right medial temporal lobe (score 0-4), and meaned. RESULTS: Mean age was 73.5 years (sd 5.1), 54% was female. Of the subjects, 15% had DM, and 70% had a history of hypertension. The likelihood of having MTA score 3 was significantly higher in subjects with DM (OR 2.9; 95% CI: 1.1-7.8) compared with an MTA score of 0 (no atrophy). The odds ratio for MTA score 2 was not significantly increased (OR 1.8; CI: 0.9-4). Systolic and diastolic blood pressure and a history of hypertension were not associated with MTA. There was no interaction between DM and hypertension. Stratification on white matter hyperintensities (WMH) did not alter the associations. CONCLUSION: Our study strengthens the observation that MTA is associated with DM, independently of the amount of small vessel disease as reflected by WMH.  相似文献   
80.
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