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   8673篇
  免费   2627篇
  国内免费   50篇
耳鼻咽喉   140篇
儿科学   152篇
妇产科学   253篇
基础医学   210篇
口腔科学   337篇
临床医学   3352篇
内科学   1573篇
皮肤病学   230篇
神经病学   968篇
特种医学   278篇
外科学   1549篇
综合类   19篇
预防医学   1261篇
眼科学   427篇
药学   84篇
肿瘤学   517篇
  2024年   81篇
  2023年   478篇
  2022年   82篇
  2021年   209篇
  2020年   366篇
  2019年   139篇
  2018年   639篇
  2017年   708篇
  2016年   642篇
  2015年   667篇
  2014年   771篇
  2013年   790篇
  2012年   239篇
  2011年   255篇
  2010年   497篇
  2009年   647篇
  2008年   227篇
  2007年   163篇
  2006年   192篇
  2005年   153篇
  2004年   100篇
  2003年   95篇
  2002年   98篇
  2001年   212篇
  2000年   89篇
  1999年   194篇
  1998年   276篇
  1997年   261篇
  1996年   324篇
  1995年   225篇
  1994年   230篇
  1993年   178篇
  1992年   148篇
  1991年   130篇
  1990年   82篇
  1989年   98篇
  1988年   82篇
  1987年   71篇
  1986年   78篇
  1985年   52篇
  1984年   53篇
  1983年   44篇
  1982年   42篇
  1981年   31篇
  1980年   26篇
  1979年   22篇
  1978年   19篇
  1977年   18篇
  1976年   14篇
  1975年   19篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
This study examines the executive function (EF) skills of extremely-low-birthweight (ELBW) children at school compared with their peers. Thirty children with ELBW and 50 control children (both with a mean age of 62+/-4 months) were administered tests of EF including the Tower of Hanoi task, Finger Sequencing task, and Tapping Test. Children with ELBW, including those who scored more than 1 SD below the mean on the Peabody Picture Vocabulary Test-Revised, scored significantly lower than their peers on all executive tasks. There was limited correlation between EF and previous general quotient index scores obtained at routine assessment using the McCarthy Scales of General Ability at 4 years of age for the children with ELBW. Results suggest that children with ELBW are at risk for deficits in 'executive' behaviours including planning, sequencing, and inhibition which may have implications for later learning.  相似文献   
992.
To investigate differences in heart rate variability (HRV) during oral glucose tolerance tests (OGTTs) in response to the rate of change in glucose and to different glycaemic ranges in individuals with type 1 diabetes. This was a single-centre, prospective, secondary outcome analysis in 17 individuals with type 1 diabetes (glycated haemoglobin 53 ± 6.3 mmol/L), who underwent two OGTTs (after 12 and 36 hours of fasting) investigating differences in HRV in response to rapid glucose increases/decreases and different glycaemic ranges during OGTT. Based on the rate of change in glucose level, the variables heart rate (P < 0.001), square root of the mean standard difference of successive R-R intervals (P = 0.002), percentage of pairs of R-R intervals with >50 ms difference (P < 0.001) and corrected QT interval (P = 0.04) were significantly altered, with HRV particularly reduced during episodes of rapid glucose rises. Glycaemic ranges during OGTT had no impact on HRV (P < 0.05). Individuals with type 1 diabetes showed no changes in HRV in response to different glycaemic ranges. HRV was dependent on the rate of change in glucose, especially rapid increases in glucose level.  相似文献   
993.
The purpose of this study was to investigate cross-sectional and longitudinal associations between hearing acuity and tooth loss in 1156 US veterans taking part in the Veterans Affairs' Normative Aging (NAS) and Dental Longitudinal (DLS) Studies in the Boston, MA, area. The mean age was 48 years (SD = 8.9), 5.3% were edentulous, and 15.4% had < 17 teeth at baseline. Hearing acuity was determined by puretone, air- and bone-conduction audiometry, and speech discrimination tests at triennial examinations over a 20-year follow-up period. Hearing decline was defined as a change from baseline in the average puretone air-conduction thresholds of ≥ 20 dB at 0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz. The explanatory variables of interest were change since baseline in dentate status (cut points at < 1, < 17, and < 20 teeth), and in the number of teeth lost (linear). Linear and logistic regression models—which controlled for baseline audiological status, age, air-bone gap, and otoscopic examination at current visit—showed that subjects who went from having ≥ 17 to < 17 teeth had 1.64 times (95% CI, 1.24-2.17) as high odds of having hearing decline as those with no change in their dentate status. For every tooth lost since baseline, there was a 1.04 times as high odds (95% CI, 1.02-1.06) for hearing decline, when additional baseline and time-varying covariates were taken into account in the model.  相似文献   
994.
995.
996.
S.W. Millar  BSc  MB  BS  FFARCS  Senior Registrar  A.C. Thurlow  MB  BS  FFARCS  Consultant  I.L. Findley  MB  ChB  DRCOG  FFARCS  Consultant 《Anaesthesia》1985,40(7):687-692
Indoramin, a competitive alpha 1-adrenoceptor antagonist, was administered intravenously to 12 fit patients aged 20-49 years during general anaesthesia with either halothane or enflurane for ear, nose and throat surgery. A mean decrease of systolic blood pressure of 6 mmHg followed the initial dose of 0.1 mg/kg. Systolic blood pressures of 70-80 mmHg were achieved in nine patients using 0.29-4 mg/kg. The maximum effect of every dose was achieved within 3 minutes, with a probable duration of action of at least 30 minutes. Large changes of heart rate did not occur, though there was gradual slowing of the heart during each series of incremental administrations. Junctional rhythm, sometimes with bradycardia and hypotension, occurred in five patients (four in halothane group; one in enflurane group). Because of this, and the greater than ten-fold variation in decrease of blood pressure for a single weight-related dose, indoramin is not recommended for the reduction of blood pressure during halothane anaesthesia.  相似文献   
997.
998.
999.
1000.
Heterozygous STAT1 gain-of-function (GOF) mutations result in a combined form of immunodeficiency which is the most common genetic cause of chronic mucocutaneous candidiasis (CMC). We present a pedigree with a GOF mutation in STAT1, manifesting with chronic demodicosis in the form of a facial papulopustular eruption, blepharitis, and chalazion. So far, demodicosis has been described in only one family with STAT1-GOF mutation. We suggest that chronic demodicosis is an under-recognized feature of the immune dysregulation disorder caused by STAT1 gain-of-function mutations.  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