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   142883篇
  免费   10316篇
  国内免费   635篇
耳鼻咽喉   1711篇
儿科学   3691篇
妇产科学   2702篇
基础医学   18188篇
口腔科学   3047篇
临床医学   14020篇
内科学   29662篇
皮肤病学   1893篇
神经病学   12742篇
特种医学   5685篇
外国民族医学   1篇
外科学   22906篇
综合类   2163篇
现状与发展   1篇
一般理论   176篇
预防医学   12931篇
眼科学   2972篇
药学   9956篇
  2篇
中国医学   179篇
肿瘤学   9206篇
  2023年   634篇
  2022年   938篇
  2021年   2644篇
  2020年   1510篇
  2019年   2438篇
  2018年   2998篇
  2017年   2169篇
  2016年   2298篇
  2015年   2799篇
  2014年   4126篇
  2013年   6219篇
  2012年   9117篇
  2011年   9706篇
  2010年   5396篇
  2009年   4935篇
  2008年   8638篇
  2007年   9253篇
  2006年   8798篇
  2005年   8944篇
  2004年   8626篇
  2003年   8157篇
  2002年   7940篇
  2001年   1523篇
  2000年   1334篇
  1999年   1619篇
  1998年   1731篇
  1997年   1378篇
  1996年   1343篇
  1995年   1290篇
  1994年   1112篇
  1993年   1091篇
  1992年   1054篇
  1991年   1091篇
  1990年   961篇
  1989年   927篇
  1988年   984篇
  1987年   949篇
  1986年   965篇
  1985年   1015篇
  1984年   1082篇
  1983年   1015篇
  1982年   1224篇
  1981年   1240篇
  1980年   1038篇
  1979年   766篇
  1978年   750篇
  1977年   685篇
  1976年   598篇
  1975年   533篇
  1974年   566篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
61.
62.
Turboprop: improved PROPELLER imaging.   总被引:1,自引:0,他引:1  
A variant of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) MRI, called turboprop, is introduced. This method employs an oscillating readout gradient during each spin echo of the echo train to collect more lines of data per echo train, which reduces the minimum scan time, motion-related artifact, and specific absorption rate (SAR) while increasing sampling efficiency. It can be applied to conventional fast spin-echo (FSE) imaging; however, this article emphasizes its application in diffusion-weighted imaging (DWI). The method is described and compared with conventional PROPELLER imaging, and clinical images collected with this PROPELLER variant are shown.  相似文献   
63.
Phenylketonuria (PKU), an inborn error of phenylalanine metabolism, has been shown to be a risk factor for tardive dyskinesia (TD). In male psychiatric patients there was a significant relationship between TD and measures of plasma phenylalanine following ingestion of a standardized phenylalanine dose that was indicative of higher brain availability of phenylalanine in patients with TD. In addition, a medical food formulation consisting of branched chain amino acids, which compete with phenylalanine for transport across the blood-brain barrier, has been demonstrated to be an efficacious treatment for TD. Cumulatively these findings suggested that TD was related to phenylalanine metabolism and thus that sequence variants in the gene for phenylalanine hydroxylase (PAH), the rate-limiting enzyme in the catabolism of phenylalanine, could be associated with TD susceptibility. Genetic screening of PAH in a group of 123 psychiatric patients revealed ten sequence polymorphisms and two mutations, but none appeared to be a significant risk factor for TD.  相似文献   
64.
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006)  相似文献   
65.
66.
67.
We report on 4 children who experienced a syncopal episode while being treated with guanfacine without any other evident cause. Syncope appears to be an uncommon side effect of guanfacine and is probably due to drug-induced hypotension or bradycardia.  相似文献   
68.
PURPOSE: Despite general worldwide acceptance of the concept of neurological determination of death (NDD), inconsistencies in clinical criteria and ancillary testing requirements remain. Numerous guidelines for NDD may be applied in clinical practice by a variety of medical practitioners, but the scientific rationale for specific guideline recommendations often remains unclear. This review examines the evolution of NDD, and seeks to provide scientific validation for existing NDD criteria. SOURCE: English language peer-reviewed medical journals and established contemporary medical texts. PRINCIPAL FINDINGS: Currently published guidelines appear to have evolved from the work of the ad hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death. The Conference of the Royal Colleges and Faculties of the United Kingdom refined the criteria and subsequently adopted the principal of brainstem death. While the fundamentals of NDD guidelines are remarkably consistent worldwide, specific criteria and requirements are often inconsistent. CONCLUSION: Numerous controversies regarding NDD continue to exist, necessitating further scientific clarification of these issues. More recently published guidelines representing the collective opinion of world experts in NDD based upon best current scientific evidence are available in current medical journals.  相似文献   
69.
Introduction Recent reviews found problem gamblers are heterogeneous and recommended subtyping gamblers in treatment studies. Objective Review factors (stage of change, preferred gambling activity, co-occurring disorder, and temporal instability of symptoms) for subtyping by evaluating the evidence for their effects on gambling treatment. Methods Literature review, evidence grading. Results Evidence is limited that any of the reviewed factors affects gambling treatment. Substantial evidence from prospective studies and other evidence from cross-sectional studies and the strong placebo response among pathological gamblers support the temporal instability of gambling symptoms. Conclusions Multiple studies are needed to develop the evidence base needed to subtype gamblers in treatment. Changes in the diagnostic criteria of pathological gambling may be necessary, especially to specify the persistence of gambling-related symptoms.  相似文献   
70.
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