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   3155675篇
  免费   235542篇
  国内免费   4752篇
耳鼻咽喉   44842篇
儿科学   105136篇
妇产科学   85909篇
基础医学   459114篇
口腔科学   86791篇
临床医学   284205篇
内科学   611844篇
皮肤病学   69648篇
神经病学   249628篇
特种医学   120086篇
外国民族医学   1096篇
外科学   477641篇
综合类   67357篇
现状与发展   12篇
一般理论   1118篇
预防医学   246863篇
眼科学   74048篇
药学   235471篇
  12篇
中国医学   6133篇
肿瘤学   169015篇
  2019年   24993篇
  2018年   34809篇
  2017年   26168篇
  2016年   29293篇
  2015年   33039篇
  2014年   46551篇
  2013年   70328篇
  2012年   96853篇
  2011年   103101篇
  2010年   61502篇
  2009年   58182篇
  2008年   97147篇
  2007年   103788篇
  2006年   104721篇
  2005年   101457篇
  2004年   97731篇
  2003年   94292篇
  2002年   91780篇
  2001年   144771篇
  2000年   149018篇
  1999年   126083篇
  1998年   36525篇
  1997年   32178篇
  1996年   32564篇
  1995年   30886篇
  1994年   28726篇
  1993年   26839篇
  1992年   98559篇
  1991年   96565篇
  1990年   94006篇
  1989年   90225篇
  1988年   83046篇
  1987年   81835篇
  1986年   76476篇
  1985年   73610篇
  1984年   55019篇
  1983年   46722篇
  1982年   27730篇
  1981年   24979篇
  1979年   50373篇
  1978年   35734篇
  1977年   30018篇
  1976年   28485篇
  1975年   30780篇
  1974年   36490篇
  1973年   34926篇
  1972年   32576篇
  1971年   30485篇
  1970年   28424篇
  1969年   26749篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
46.
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   
47.
48.
49.
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   
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