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   3166227篇
  免费   233279篇
  国内免费   4923篇
耳鼻咽喉   45009篇
儿科学   104208篇
妇产科学   88318篇
基础医学   464354篇
口腔科学   88412篇
临床医学   283321篇
内科学   608748篇
皮肤病学   69292篇
神经病学   250286篇
特种医学   120331篇
外国民族医学   819篇
外科学   480224篇
综合类   67104篇
现状与发展   12篇
一般理论   1084篇
预防医学   246227篇
眼科学   74857篇
药学   237762篇
  11篇
中国医学   6181篇
肿瘤学   167869篇
  2018年   34362篇
  2017年   25801篇
  2016年   29019篇
  2015年   32915篇
  2014年   46193篇
  2013年   69780篇
  2012年   96148篇
  2011年   102450篇
  2010年   60860篇
  2009年   57404篇
  2008年   96925篇
  2007年   103544篇
  2006年   104719篇
  2005年   101818篇
  2004年   97708篇
  2003年   94238篇
  2002年   91678篇
  2001年   140849篇
  2000年   144504篇
  1999年   121908篇
  1998年   36010篇
  1997年   31700篇
  1996年   32029篇
  1995年   30195篇
  1994年   27986篇
  1993年   26325篇
  1992年   96091篇
  1991年   94006篇
  1990年   92142篇
  1989年   89158篇
  1988年   82374篇
  1987年   80884篇
  1986年   76484篇
  1985年   73329篇
  1984年   54793篇
  1983年   46907篇
  1982年   28231篇
  1981年   25259篇
  1979年   51229篇
  1978年   36433篇
  1977年   30806篇
  1976年   29348篇
  1975年   31951篇
  1974年   37970篇
  1973年   36404篇
  1972年   34365篇
  1971年   32416篇
  1970年   29993篇
  1969年   28691篇
  1968年   26675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