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   2540798篇
  免费   177375篇
  国内免费   3395篇
耳鼻咽喉   33514篇
儿科学   82956篇
妇产科学   66064篇
基础医学   368321篇
口腔科学   65698篇
临床医学   225033篇
内科学   492331篇
皮肤病学   52822篇
神经病学   203526篇
特种医学   97634篇
外国民族医学   492篇
外科学   386570篇
综合类   50601篇
现状与发展   12篇
一般理论   910篇
预防医学   201332篇
眼科学   57431篇
药学   185450篇
  11篇
中国医学   5223篇
肿瘤学   145637篇
  2021年   19337篇
  2019年   19903篇
  2018年   47760篇
  2017年   36843篇
  2016年   42064篇
  2015年   26961篇
  2014年   37453篇
  2013年   55665篇
  2012年   82497篇
  2011年   100341篇
  2010年   64799篇
  2009年   56273篇
  2008年   94661篇
  2007年   102552篇
  2006年   82407篇
  2005年   81804篇
  2004年   79885篇
  2003年   78498篇
  2002年   74143篇
  2001年   109366篇
  2000年   112338篇
  1999年   94002篇
  1998年   27555篇
  1997年   24265篇
  1996年   24476篇
  1995年   23149篇
  1994年   21275篇
  1993年   20071篇
  1992年   72326篇
  1991年   70446篇
  1990年   68746篇
  1989年   65949篇
  1988年   60541篇
  1987年   59369篇
  1986年   55432篇
  1985年   53249篇
  1984年   39562篇
  1983年   33630篇
  1982年   20169篇
  1979年   36073篇
  1978年   25822篇
  1977年   21321篇
  1976年   20491篇
  1975年   21889篇
  1974年   26257篇
  1973年   24870篇
  1972年   23247篇
  1971年   22076篇
  1970年   20313篇
  1969年   19378篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Graefe's Archive for Clinical and Experimental Ophthalmology - The published online version contains mistake as the author's first name and last name have been interchanged as "Hild...  相似文献   
32.
33.
34.
35.
36.
Abstract

Objective: This study aims at identifying associations between cognitive function and suicidal ideation in the sample of patients with anxiety and mood disorders (AMD).

Methods: In sum, 186 (age = 39?±?12.3 years; 142 [76.3%] females) patients with AMD were enrolled in the study. Assessment included evaluation of socio-demographic information, medication use, anxiety and depression symptoms. Cognitive tests included measures of psychomotor performance and incidental learning using the Digit Symbol Test. Trail Making Tests respectively measured perceptual speed, task-switching and executive control. Additionally, 21 patients completed tests from the Cambridge Automated Neuropsychological Test Battery measuring set shifting (Interdimensional/extradimensional set-shift), executive planning (Stockings of Cambridge), and decision making (Cambridge Gamble Task [CGT]).

Results: Almost half (45.0%, n?=?86) of the study sample patients had experienced suicidal ideations. In multivariable regression analysis, suicidal ideation was associated with a greater overall proportion of bet and risk taking on the CGT task (β?=?0.726, p?=?.010 and β?=?0.634, p?=?.019), when controlling for socio-demographic characteristics, medication use, anxiety and depression symptoms.

Conclusions: Outpatients with AMD and suicidal ideation could be distinguished by the presence of cognitive deficits in the executive function domain, particularly in impulse-control and risk taking.  相似文献   
37.
38.
39.
The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (Leq) measurements were collected during flight operations (Leq (flt ops)), non-flight operations (Leq (non-flt ops)), and over 24-hr periods (Leq (24-hr)). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Value (TLV®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The Leq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between Leq (flt ops), Leq (non-flt ops), and Leq (24-hr) and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) Leq (24-hr): 70.8–105.4 dBA; (2) Leq (flt ops): 70–101.2 dBA; and (3) Leq (non-flt ops): 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean Leqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The Leqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.  相似文献   
40.
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