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   2679765篇
  免费   196691篇
  国内免费   4072篇
耳鼻咽喉   36765篇
儿科学   86681篇
妇产科学   72427篇
基础医学   393388篇
口腔科学   72247篇
临床医学   241248篇
内科学   521431篇
皮肤病学   57897篇
神经病学   213483篇
特种医学   100265篇
外国民族医学   539篇
外科学   405967篇
综合类   55292篇
现状与发展   15篇
一般理论   1198篇
预防医学   210440篇
眼科学   62344篇
药学   198213篇
  12篇
中国医学   5194篇
肿瘤学   145482篇
  2021年   22494篇
  2019年   22992篇
  2018年   31737篇
  2017年   24037篇
  2016年   26740篇
  2015年   30366篇
  2014年   42847篇
  2013年   64545篇
  2012年   88633篇
  2011年   94584篇
  2010年   56386篇
  2009年   52970篇
  2008年   89203篇
  2007年   95017篇
  2006年   95498篇
  2005年   93096篇
  2004年   89231篇
  2003年   85704篇
  2002年   82907篇
  2001年   117554篇
  2000年   120094篇
  1999年   101537篇
  1998年   30829篇
  1997年   27103篇
  1996年   27269篇
  1995年   25650篇
  1994年   23660篇
  1993年   22281篇
  1992年   77848篇
  1991年   76003篇
  1990年   74202篇
  1989年   71345篇
  1988年   65613篇
  1987年   64431篇
  1986年   60325篇
  1985年   58073篇
  1984年   43480篇
  1983年   37190篇
  1982年   22847篇
  1979年   39491篇
  1978年   28537篇
  1977年   23810篇
  1976年   22728篇
  1975年   24385篇
  1974年   29111篇
  1973年   27741篇
  1972年   25852篇
  1971年   24503篇
  1970年   22653篇
  1969年   21410篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.
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   
45.
46.
47.
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   
48.
49.
50.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
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