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   3034篇
  免费   43篇
  国内免费   1篇
教育   2257篇
科学研究   181篇
各国文化   40篇
体育   352篇
综合类   2篇
文化理论   64篇
信息传播   182篇
  2023年   29篇
  2022年   47篇
  2021年   85篇
  2020年   130篇
  2019年   221篇
  2018年   247篇
  2017年   248篇
  2016年   213篇
  2015年   147篇
  2014年   153篇
  2013年   662篇
  2012年   117篇
  2011年   82篇
  2010年   69篇
  2009年   59篇
  2008年   62篇
  2007年   56篇
  2006年   48篇
  2005年   39篇
  2004年   32篇
  2003年   30篇
  2002年   37篇
  2001年   17篇
  2000年   16篇
  1999年   15篇
  1998年   16篇
  1997年   10篇
  1996年   18篇
  1995年   12篇
  1994年   12篇
  1993年   13篇
  1992年   11篇
  1991年   16篇
  1990年   13篇
  1989年   8篇
  1988年   10篇
  1987年   5篇
  1985年   4篇
  1984年   5篇
  1983年   5篇
  1981年   4篇
  1979年   5篇
  1977年   6篇
  1976年   4篇
  1975年   3篇
  1973年   3篇
  1971年   3篇
  1970年   3篇
  1965年   3篇
  1963年   3篇
排序方式: 共有3078条查询结果,搜索用时 15 毫秒
111.
Research into unsupervised ways of stemming has resulted, in the past few years, in the development of methods that are reliable and perform well. Our approach further shifts the boundaries of the state of the art by providing more accurate stemming results. The idea of the approach consists in building a stemmer in two stages. In the first stage, a stemming algorithm based upon clustering, which exploits the lexical and semantic information of words, is used to prepare large-scale training data for the second-stage algorithm. The second-stage algorithm uses a maximum entropy classifier. The stemming-specific features help the classifier decide when and how to stem a particular word.  相似文献   
112.
The discovery of protein biomarkers that reflect the biological state of the body is of vital importance to disease management. Urine is an ideal source of biomarkers that provides a non-invasive approach to diagnosis, prognosis and prediction of diseases. Consequently, the study of the human urinary proteome has increased dramatically over the last 10 years, with many studies being published. This review focuses on urinary protein biomarkers that have shown potential, in initial studies, for diseases affecting the urogenital tract, specifically chronic kidney disease and prostate cancer, as well as other non-urogenital pathologies such as breast cancer, diabetes, atherosclerosis and osteoarthritis. PubMed was searched for peer-reviewed literature on the subject, published in the last 10 years. The keywords used were “urine, biomarker, protein, and/or prostate cancer/breast cancer/chronic kidney disease/diabetes/atherosclerosis/osteoarthritis”. Original studies on the subject, as well as a small number of reviews, were analysed including the strengths and weaknesses, and we summarized the performance of biomarkers that demonstrated potential. One of the biggest challenges found is that biomarkers are often shared by several pathologies so are not specific to one disease. Therefore, the trend is shifting towards implementing a panel of biomarkers, which may increase specificity. Although there have been many advances in urinary proteomics, these have not resulted in similar advancements in clinical practice due to high costs and the lack of large data sets. In order to translate these potential biomarkers to clinical practice, vigorous validation is needed, with input from industry or large collaborative studies.Key words: urine, protein, biomarker  相似文献   
113.
114.
The reporting of intellectual capital (IC) in higher education institutions is of vital importance, mainly owing to the fact that knowledge is the main output and input in these institutions. Furthermore, the increasing social concern about establishing procedures of accountability and ensuring information transparency in public universities prompted us to consider the need to disclose information on their IC. In this study, we developed a questionnaire that was sent to members of the Social Councils of Spanish public universities in order to identify the intangible elements about which university stakeholders demand most information. It was also used to see which groups of universities have stakeholders who are more proactive to the disclosure of IC. Our results represent a starting point for public universities to identify the most commonly requested information about IC. Universities can then develop an IC report that fits their own characteristics and environment.  相似文献   
115.
116.
The Spanish Service was established in June 1939, two months after the end of the civil war in Spain and shortly before the start of the Second World War. Its implementation was strongly affected by these conflicts in the context of new international relations. Therefore, this study of the Spanish Service during 1939–1945 allows not only a better understanding of the communicational strategies developed by the BBC, but also of the complex Anglo-Spanish relations and the important role played by the Spanish-language broadcasts therein. The study is mainly based on archival documents from the National Archives in London and memoirs.  相似文献   
117.
People still use documents in many everyday government processes. From tax payments to passport requests, citizens have to interact with low-interactivity information artifacts such as reports, maps and datasets, among many others. Despite efforts to improve information delivery in the public sector, effective information usage remains a critical topic of action and research. The user experience of government documents has rarely been assessed, despite them being regularly published and frequently used. Considering this, the two following research questions arise: 1) How can government documents be classified (or grouped) in terms of user experience? 2) How can the user experience of government documents be monitored over time in order to inform design decisions? Working with a public agency in Chile, we develop and test a classification and monitoring framework based on two online surveys (N?=?338 and N?=?298). We then propose a framework for understanding user experience of government documents in these three dimensions: interaction goal, volume of information and ease of understanding. Using a graphical representation to classify user experience provides greater visibility of the current status of information produced by a public organization. Furthermore, by monitoring the user experience of a government document at different times, organizations can understand the effect of their design decisions and improve their service quality by implementing user-centered processes.  相似文献   
118.
The combined effects of pH and temperature on red pigment production and fungal morphology were evaluated in a submerged culture of Penicillium purpurogenum GH2, using Czapek-Dox media with d-xylose as a carbon source. An experimental design with a factorial fix was used: three pH values (5, 7, and 9) and two temperature levels (24 and 34 °C) were evaluated. The highest production of red pigment (2.46 g/L) was reached with a pH value of 5 and a temperature of 24 °C. Biomass and red pigment production were not directly associated. This study demonstrates that P. purpurogenum GH2 produces a pigment of potential interest to the food industry. It also shows the feasibility of producing and obtaining natural water-soluble pigments for potential use in food industries. A strong combined effect (p<0.05) of pH and temperature was associated with maximal red pigment production (2.46 g/L).  相似文献   
119.
This study investigated development of the Big Five personality traits from early childhood into adulthood. An initial group of 137 Swedish children were assessed eight times between ages 2 and 29 years. Initial decreases in extraversion leveled off in early adulthood; agreeableness and conscientiousness increased from ages 2 to 29; neuroticism initially increased, leveled off in later childhood and adolescence, and decreased throughout early adulthood; while openness to experience showed an initial increase, then decreased and leveled off in early adulthood. Individual developmental trajectories varied significantly, particularly in relation to gender. Personality traits became increasingly stable, and the fact that childhood scores predicted scores in adulthood indicated that personalities are fairly stable across this portion of the life span.  相似文献   
120.
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