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   532篇
  免费   98篇
  国内免费   45篇
  675篇
  2024年   23篇
  2023年   14篇
  2022年   18篇
  2021年   27篇
  2020年   25篇
  2019年   17篇
  2018年   29篇
  2017年   26篇
  2016年   26篇
  2015年   13篇
  2014年   24篇
  2013年   33篇
  2012年   34篇
  2011年   37篇
  2010年   26篇
  2009年   30篇
  2008年   25篇
  2007年   58篇
  2006年   48篇
  2005年   40篇
  2004年   20篇
  2003年   13篇
  2002年   13篇
  2001年   9篇
  2000年   6篇
  1999年   5篇
  1998年   3篇
  1997年   3篇
  1996年   4篇
  1995年   1篇
  1994年   4篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
排序方式: 共有675条查询结果,搜索用时 0 毫秒
611.
    
  相似文献   
612.
    
Breakwater structures made of concrete are used widely around the world, and the bacteria living on these surfaces can cause the concrete to deteriorate. In this study, we collected bacterial biofilms from concrete breakwater structures located along the coast of an island, a mainland coast, and a freshwater riverbank as well as planktonic water samples from each site, and we analysed their bacterial community structures using Illumina sequencing. At the phylum level, Proteobacteria and Actinobacteria dominated planktonic samples, whereas Cyanobacteria, Proteobacteria and Bacteroidetes dominated the biofilm samples. High Cyanobacteria abundance was found in all biofilm samples. Bacterial communities significantly varied between planktonic and biofilm samples and between biofilm samples from seawater and freshwater. Only a small number of bacterial operational taxonomic units were shared by planktonic and biofilm samples from each sampling site. The permanganate index in ambient water had a more significant impact on biofilm bacterial communities than on planktonic samples. Additionally, ammonia nitrogen and total nitrogen contents were positively correlated and salinity was negatively correlated with bacterial beta diversity in biofilm samples.  相似文献   
613.
    
The aim of this study is to contribute to a better understanding of extreme response style in cross‐cultural research by integrating quantitative and qualitative evidence in a mixed methods design. In the quantitative phase, indexes of extreme response style, derived from quality of life measures from different international studies, were compared between Spain and the Netherlands. Results indicated that extreme responding was more common among Spanish than among Dutch in endorsement of items, but that the opposite was found for frequency scales including never as a response anchor. In the qualitative phase, cognitive interviews were conducted with 25 participants in each country. The integration of quantitative results and qualitative findings suggests that country differences in extreme response style may stem from various sources, including the more independent evaluation of each item by Dutch, the stronger connotations of never for Spanish and stronger emotions triggered by specific topics such as work satisfaction that was more strongly associated with insecurity for Spanish. It is concluded that the integration of quantitative and qualitative evidence can help to understand cross‐cultural similarities and differences in extreme response style.  相似文献   
614.
    
Colonization and development of gut microbiota during early life stage plays a key regulatory role in the establishment of the host–microbial relationship, which was conducive to progressing host immunity and maintaining health throughout the adulthood life span. This study was aimed to evaluate the protective effect from inflammatory bowel disease (IBD) in adulthood based on the early intervention of Lactobacillus paracasei N1115 (LP N1115). LP N1115 treatment was carried out during 2 weeks in postnatal mice. Then the dextran sodium sulphate (DSS)-induced colitis model mice were established in adulthood, and the status of intestinal tissues was detected. Results showed the decreased severity of intestinal tissue injury, cell apoptosis, and proinflammatory cytokines expression in DSS-induced model with LP N1115 early intervention. Therefore, the intake of LP N1115 in neonatal mice has played a long-term healthy role in the prevention of intestinal injury and inflammation in adulthood.  相似文献   
615.
    
Two studies examine the role of the cultural value orientation, self‐construal, as a moderator of the relationship between social presence and service satisfaction. Cross‐cultural data are collected in China and the USA to maximize variation on self‐construal. Results suggest that social presence effects vary depending on the consumer's independent self‐construal. Regardless of whether the service encounter is positive or negative, social presence increases the strength of satisfaction or dissatisfaction for low independents but not for high independents. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
616.
本实验采用闪烁光度法。本实验的视野是7°40′和20′,受试者5人,均属色觉正常者。年龄在30至50岁之间,具有一定实验经验。实验波长从420—700nm,其间隔为20nm,实验的亮度级为30cd/m~2。 四种视野相比较,其中2°视野V(λ)曲线引自明视函数,10°视角的材料来自CIE1964年补充标准观察者?10(λ),其结果:峰值的短波一侧随着视野的增加V(λ)值显著增加,而在峰值的长波一侧则无显著变化。  相似文献   
617.
时间信息在情景模型建构中的作用   总被引:3,自引:0,他引:3       下载免费PDF全文
考察时间信息在情景模型建构中的作用 ,探讨被试能否把一系列相关的事实整合进基于时间组织的情景模型中。实验一、二考察明确的空间信息条件下 ,被试能否把绝对和相对的时间信息整合到情景模型中 ;实验三考察无明确的空间信息条件下 ,被试能否把绝对的时间信息整合到情景模型中。运用扇效应研究的提取干扰技术评定是否出现了整合。 3个实验结果一致表明 ,当几个相关的事实发生在相同的时间段时 ,都发现被试建构了基于时间的情景模型的证据。实验三结果同时也表明 ,无明确的空间信息的条件下 ,阅读材料中时间信息本身足以使被试建构基于时间组织的情景模型。  相似文献   
618.
无意识工作激励是指由外部环境自动诱导出个体努力行为的过程,并且这种自动诱导的过程无法被个体所内省。目前已经被发现的无意识工作激励过程包括自动化评价,无意识行为模仿,态度、特质和刻板印象的激活,以及无意识目标激活等。从内在机制来看,镜像神经元理论可解释无意识行为模仿,无意识行为选择模型可用来解释无意识目标激励。未来应侧重研究无意识工作激励与有意识工作激励的关系,发展新的研究方法,并更深入地探索无意识工作激励的内在机制。  相似文献   
619.
设计新的空间视角采择任务,考察成人空间视角采择的自动性。结果发现:(1)在other任务中,随着人偶与被试的角度差异增加,反应时和错误率升高。(2)在self任务中,空间关系一致时正确率高于不一致时,且150°-180°间的一致性效应不显著;随着角度差异增加,反应时升高;小球与人偶的空间关系和空间关系的一致性交互作用不显著。本研究结果表明:本实验任务对成人而言是一个有效的空间视角采择任务;成人可以自动地做空间视角采择;人偶与被试的角度差异影响成人空间视角采择的自动性;小球与人偶的空间关系不影响成人空间视角采择的自动性。本研究首次证明了成人可以自动做空间视角采择。  相似文献   
620.
Benzodiazepine pharmacology has led to greater insight into the neural mechanisms underlying learning and anxiety. The synthesis of new compounds capable of modulating responses produced by these receptors has been made possible by the development of an isoform model of the GABA(A)/benzodiazepine receptor complex. In the current experiment, rats were pretreated with several concentrations of the novel ligand RY024 (an alpha 5 beta 2 gamma 2 -selective benzodiazepine receptor inverse agonist) in the hippocampus and were trained in a Pavlovian fear conditioning paradigm. RY024 independently produced fear-related behavior prior to training and, at the highest concentration, decreased the strength of conditioning observed 24 h after training. These data provide further evidence for the involvement of hippocampal GABA(A)/benzodiazepine receptors in learning and anxiety.  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