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   3157030篇
  免费   235735篇
  国内免费   4751篇
耳鼻咽喉   44839篇
儿科学   105090篇
妇产科学   85997篇
基础医学   459388篇
口腔科学   86827篇
临床医学   284384篇
内科学   611948篇
皮肤病学   69720篇
神经病学   249762篇
特种医学   120042篇
外国民族医学   1096篇
外科学   477830篇
综合类   67409篇
现状与发展   12篇
一般理论   1120篇
预防医学   247142篇
眼科学   74086篇
药学   235569篇
  12篇
中国医学   6139篇
肿瘤学   169104篇
  2019年   25007篇
  2018年   34821篇
  2017年   26192篇
  2016年   29319篇
  2015年   33041篇
  2014年   46579篇
  2013年   70354篇
  2012年   96876篇
  2011年   103120篇
  2010年   61524篇
  2009年   58200篇
  2008年   97194篇
  2007年   103859篇
  2006年   104785篇
  2005年   101503篇
  2004年   97796篇
  2003年   94357篇
  2002年   91861篇
  2001年   144820篇
  2000年   149056篇
  1999年   126147篇
  1998年   36556篇
  1997年   32197篇
  1996年   32586篇
  1995年   30899篇
  1994年   28738篇
  1993年   26860篇
  1992年   98594篇
  1991年   96584篇
  1990年   94047篇
  1989年   90255篇
  1988年   83077篇
  1987年   81873篇
  1986年   76516篇
  1985年   73642篇
  1984年   55050篇
  1983年   46738篇
  1982年   27744篇
  1981年   24995篇
  1979年   50405篇
  1978年   35753篇
  1977年   30028篇
  1976年   28512篇
  1975年   30793篇
  1974年   36517篇
  1973年   34944篇
  1972年   32590篇
  1971年   30494篇
  1970年   28435篇
  1969年   26761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