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   3156004篇
  免费   232539篇
  国内免费   4892篇
耳鼻咽喉   44885篇
儿科学   103876篇
妇产科学   88140篇
基础医学   463337篇
口腔科学   88297篇
临床医学   281912篇
内科学   606645篇
皮肤病学   69120篇
神经病学   249471篇
特种医学   119986篇
外国民族医学   818篇
外科学   478937篇
综合类   66850篇
现状与发展   12篇
一般理论   1076篇
预防医学   245151篇
眼科学   74367篇
药学   237146篇
  11篇
中国医学   6172篇
肿瘤学   167226篇
  2018年   34127篇
  2017年   25652篇
  2016年   28826篇
  2015年   32700篇
  2014年   45892篇
  2013年   69357篇
  2012年   95549篇
  2011年   101849篇
  2010年   60520篇
  2009年   57052篇
  2008年   96360篇
  2007年   102953篇
  2006年   104110篇
  2005年   101271篇
  2004年   97177篇
  2003年   93693篇
  2002年   91170篇
  2001年   140709篇
  2000年   144316篇
  1999年   121727篇
  1998年   35885篇
  1997年   31579篇
  1996年   31962篇
  1995年   30079篇
  1994年   27900篇
  1993年   26233篇
  1992年   95962篇
  1991年   93870篇
  1990年   92005篇
  1989年   89029篇
  1988年   82258篇
  1987年   80765篇
  1986年   76383篇
  1985年   73209篇
  1984年   54686篇
  1983年   46823篇
  1982年   28164篇
  1981年   25198篇
  1979年   51170篇
  1978年   36388篇
  1977年   30754篇
  1976年   29299篇
  1975年   31909篇
  1974年   37917篇
  1973年   36348篇
  1972年   34325篇
  1971年   32372篇
  1970年   29959篇
  1969年   28658篇
  1968年   26650篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.
45.
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   
46.
47.
48.
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   
49.
50.
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