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   2664499篇
  免费   188106篇
  国内免费   4014篇
耳鼻咽喉   36922篇
儿科学   87870篇
妇产科学   73518篇
基础医学   391244篇
口腔科学   72889篇
临床医学   236750篇
内科学   514244篇
皮肤病学   59078篇
神经病学   207154篇
特种医学   103467篇
外国民族医学   614篇
外科学   402488篇
综合类   53504篇
现状与发展   13篇
一般理论   961篇
预防医学   207093篇
眼科学   62213篇
药学   197288篇
  12篇
中国医学   5054篇
肿瘤学   144243篇
  2019年   20843篇
  2018年   31975篇
  2017年   25042篇
  2016年   27077篇
  2015年   31606篇
  2014年   42279篇
  2013年   61034篇
  2012年   87804篇
  2011年   88331篇
  2010年   52454篇
  2009年   50891篇
  2008年   81120篇
  2007年   86967篇
  2006年   88013篇
  2005年   91981篇
  2004年   89953篇
  2003年   83122篇
  2002年   76613篇
  2001年   118386篇
  2000年   119951篇
  1999年   102940篇
  1998年   29185篇
  1997年   25489篇
  1996年   25868篇
  1995年   24444篇
  1994年   22517篇
  1993年   21206篇
  1992年   80652篇
  1991年   78988篇
  1990年   77415篇
  1989年   74581篇
  1988年   68531篇
  1987年   67217篇
  1986年   63020篇
  1985年   60290篇
  1984年   44494篇
  1983年   37800篇
  1982年   22127篇
  1979年   41272篇
  1978年   29324篇
  1977年   24287篇
  1976年   23045篇
  1975年   25446篇
  1974年   30545篇
  1973年   29082篇
  1972年   27351篇
  1971年   26084篇
  1970年   24103篇
  1969年   22847篇
  1968年   21127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