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   40216篇
  免费   3908篇
  国内免费   2878篇
电工技术   1119篇
综合类   4241篇
化学工业   4756篇
金属工艺   5336篇
机械仪表   3658篇
建筑科学   6104篇
矿业工程   2607篇
能源动力   1140篇
轻工业   2273篇
水利工程   1947篇
石油天然气   2378篇
武器工业   352篇
无线电   1174篇
一般工业技术   6186篇
冶金工业   2611篇
原子能技术   325篇
自动化技术   795篇
  2024年   118篇
  2023年   436篇
  2022年   1415篇
  2021年   1752篇
  2020年   1247篇
  2019年   1160篇
  2018年   1071篇
  2017年   1327篇
  2016年   1454篇
  2015年   1518篇
  2014年   2270篇
  2013年   2432篇
  2012年   2684篇
  2011年   3003篇
  2010年   2292篇
  2009年   2362篇
  2008年   2190篇
  2007年   2617篇
  2006年   2303篇
  2005年   2011篇
  2004年   1739篇
  2003年   1461篇
  2002年   1300篇
  2001年   1093篇
  2000年   970篇
  1999年   802篇
  1998年   677篇
  1997年   597篇
  1996年   499篇
  1995年   410篇
  1994年   348篇
  1993年   280篇
  1992年   254篇
  1991年   171篇
  1990年   156篇
  1989年   149篇
  1988年   94篇
  1987年   67篇
  1986年   41篇
  1985年   35篇
  1984年   41篇
  1983年   18篇
  1982年   28篇
  1981年   10篇
  1980年   15篇
  1979年   21篇
  1964年   10篇
  1961年   6篇
  1959年   8篇
  1955年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
The authors examined relationships between chronic stress and cognitive decline and whether such relationships were mediated by psychophysiological factors. Ninety-six caregivers of spouses with Alzheimer's disease (AD) were compared with 95 similar noncaregiver spouses. All were free of diabetes. Although the groups started similarly, over 2 years caregivers declined by a small but significant amount (1 raw score point and 4 percentile points, each p  相似文献   
993.
The authors argue that posttraumatic stress disorder (PTSD) is not an automatic consequence of a trauma. A review of empirical research demonstrates that there must be subjective mediating factors. On the basis of a conceptual reasoning, the existence of an actual-neurotic structure prior to the traumatic event is put forward as a precondition for the development of PTSD. Freud's theory on actual neurosis is interpreted as the impossibility to process the arousal coming from the drive in a symbolic way. The reason for this impossibility is sought in the failure of the primary caretakers in presenting the child with the necessary symbolic tools for drive regulation. The therapeutic implications of the presence of an actual-neurotic structure are important, because it can lead to a failure of free association. Suggestions for a more fruitful approach are formulated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
994.
The Changes in Outlook Questionnaire (CiOQ; S. Joseph, R. Williams, & W. Yule, 1993) is a 26-item self-report measure that was designed to assess positive and negative changes in the aftermath of adversity. This article had 3 aims: 1st, to investigate the factor structure of the CiOQ; 2nd, to test for internal consistency reliability and convergent and discriminant validity; and, 3rd, to investigate the association between positive and negative changes in outlook, posttraumatic stress, and psychological distress. Three studies are reported. Study 1 provides evidence that positive and negative changes are statistically separable and that the 2-factor model is a better fit than the 1-factor model. Studies 2 and 3 provide evidence for internal consistency reliability, convergent and discriminant validity of the CiOQ, and its associations with posttraumatic stress and psychological distress. In conclusion, the CiOQ has much promise for research on responses to stressful and traumatic events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
995.
The current study used ecological momentary assessment to test several tenets of the reserve capacity model (L.C. Gallo & K. A. Matthews, 2003). Women (N = 108) with varying socioeconomic status (SES) monitored positive and negative psychosocial experiences and emotions across 2 days. Measures of intrapsychic and social resources were aggregated to represent the reserve capacity available to manage stress. Lower SES was associated with less perceived control and positive affect and more social strain. Control and strain contributed to the association between SES and positive affect. Lower SES elicited greater positive but not negative emotional reactivity to psychosocial experiences. Women with low SES had fewer resources relative to those with higher SES, and resources contributed to the association between SES and daily experiences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
996.
Objective: To evaluate the feasibility of a telehealth psychoeducation intervention for persons with schizophrenia and their family members. Study Design: Randomized controlled trial. Participants: 30 persons with schizophrenia and 21 family members or other informal support persons. Interventions: Web-based psychoeducation program that provided online group therapy and education. Main Outcome Measures: Measures for persons with schizophrenia included perceived stress and perceived social support; for family members, they included disease-related distress and perceived social support. Results: At 3 months, participants with schizophrenia in the intervention group reported lower perceived stress (p = .04) and showed a trend for a higher perceived level of social support (p = .06). Conclusions: The findings demonstrate the feasibility and impact of providing telehealth-based psychosocial treatments, including online therapy groups, to persons with schizophrenia and their families. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
997.
This article had 2 aims: (a) to comprehensively review and synthesize the literature on predictors of health service utilization in survivors of traumatic events and posttraumatic stress disorder (PTSD) patients and (b) to discuss methodological issues in examining service utilization in this population. PsycINFO was searched for relevant articles published through April 2004. Included studies had to primarily sample trauma survivors or PTSD patients and statistically explore health service use determinants. Although some findings conflicted across studies, increased mental health service use was generally related to being female, having a previous trauma history, and having a PTSD diagnosis. Increased medical service use was found among those with a PTSD diagnosis. Methodological recommendations are made for future health service use studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
998.
利用扫描电镜和EDXA对新锆合金碘致应力腐蚀的断口进行了形貌观察和成分分析。在断口表面发现腐蚀产物、二次裂纹、沿晶开裂和穿晶准解理开裂等应力腐蚀断裂特征,并观察到锆合金碘致应力腐蚀的“沟槽”特征。起裂区为沿晶开裂,在裂纹扩展阶段,开裂以穿晶为主。断口上腐蚀产物的成分主要是氧和锆,局部准解理开裂区域可检测到碘。去应力退火试样上发现了平行轧面的深沟,且沿晶开裂不明显。试验温度升高,断口上的腐蚀产物增多,而且沿晶开裂更容易。碘分压不仅影响腐蚀产物层的厚度,而且碘分压较高时沿晶开裂容易发生。  相似文献   
999.
对V型钢导轨在热处理后的磨削加工中出现的表面裂纹进行了宏、微观分析,硬度测试及热酸蚀试验。结果表明,磨削不当是导致V型钢导轨出现表面裂纹的主要原因。提出了改进措施。  相似文献   
1000.
前瞻记忆与紧张度的关系研究   总被引:3,自引:0,他引:3  
紧张状态下的前瞻记忆表现是应急反应研究的一个新视角。运用自行研制的实验材料,在前瞻记忆的实验法范式下,对不同呈现速度(即紧张程度)和分心条件下,前瞻记忆的绩效进行了比较。结果发现前瞻记忆的绩效随紧张程度增大而显著降低;快速比慢速受分心影响小,并且这种趋势接近显著水平。此研究对于探讨前瞻记忆在紧急突发事件中的应用,具有重要的借鉴意义。  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