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   3856篇
  免费   25篇
  国内免费   4篇
教育   2759篇
科学研究   487篇
各国文化   20篇
体育   174篇
综合类   6篇
文化理论   79篇
信息传播   360篇
  2023年   4篇
  2022年   16篇
  2021年   21篇
  2020年   25篇
  2019年   43篇
  2018年   111篇
  2017年   151篇
  2016年   214篇
  2015年   96篇
  2014年   71篇
  2013年   267篇
  2012年   95篇
  2011年   208篇
  2010年   121篇
  2009年   162篇
  2008年   80篇
  2007年   90篇
  2006年   90篇
  2005年   719篇
  2004年   571篇
  2003年   318篇
  2002年   104篇
  2001年   63篇
  2000年   36篇
  1999年   14篇
  1998年   15篇
  1997年   6篇
  1996年   11篇
  1995年   7篇
  1994年   9篇
  1993年   5篇
  1991年   8篇
  1989年   6篇
  1988年   5篇
  1987年   11篇
  1986年   4篇
  1985年   8篇
  1984年   5篇
  1983年   6篇
  1982年   5篇
  1981年   4篇
  1979年   7篇
  1977年   10篇
  1976年   6篇
  1975年   5篇
  1973年   6篇
  1972年   4篇
  1971年   4篇
  1970年   4篇
  1966年   3篇
排序方式: 共有3885条查询结果,搜索用时 15 毫秒
61.
Theories of adolescent connectedness suggest that adolescents strive to become connected by engaging with and valuing the people, activities, and worlds in their social ecology. The purpose of this study was to examine the psychometric properties of a measure designed to assess these worlds of connectedness among 320 junior high school students in Taiwan. The subscales and composite scales evidenced satisfactory reliability and concurrent validity. A hypothesized three-factor, higher order structural model of connectedness was cross-validated. Girls were generally more connected than boys. Both connectedness to school and to friends explained more variance in connectedness to self than did family connectedness. There was mixed support for separation-individuation processes. The measure appears promising in terms of future research on adolescent social development in the Asia Pacific.  相似文献   
62.
The first year of a 5 year professional development project for elementary teachers in two mid-western states integrated a bridge of two distinctly different distance education networks (T-1 and fiber optics) to provide science professional development for elementary school teachers in rural communities. Interactive television (ITV), the title given to the distance component, consisted of a series of twenty-four, 2 h presentations by scientists and content specialists. It provided expansion to the science pedagogical content knowledge of the elementary teachers involved. Eighty-five teachers in 38 school districts from the two states completed individual surveys following the final ITV session. Analysis of variance of participants post-session survey scores yielded differences (p < 0.05) on the subscales measuring perceived effectiveness of using distance education for professional development purposes and years of teaching experience. Teachers with over 20 years of classroom experience perceived the use of distance education technologies for science professional development to be more effective than teachers with 16–20 years of classroom experience. These results might suggest another digital divide.  相似文献   
63.
64.
65.
Luciferase from firefly lantern extract was immobilized on CNBr-activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. TheK m′ for D-luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose-bound enzyme were 7.8 and 25°C respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10−9–10−5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.  相似文献   
66.
67.
In 2001, for the first time in the history of the International Association for Counselling, International Conference was held in a developing Asian country–India, with the theme Families in Transition–Counselling in Transition–Meeting the Challenges Ahead. This special issue contains some of the presentations made by Indian participants during this conference which best reflect the challenges and diversities of counseling efforts with families in India. The first article was specially written for this issue in order to give an international relationship of this journal an in depth contextual understanding of Indian families in transition and the challenges they pose to the contemporary Indian counselor. Two articles are reflected to counseling families affected by socio-politial and economic changes. Five authors have written on counseling related to physical and mental disability/addiction and last two articles are reflected to authors experiences as family counselors.  相似文献   
68.
69.
The effects of identical context on pattern recognition by pigeons for outline drawings of faces were investigated by training pigeons to identify (Experiment 1) and categorize (Experiment 2) these stimuli according to the orientation of the mouth—an upright U shape representing a smiling mouth or an inverted U shape representing a sad mouth. These target stimuli were presented alone (Pair 1), with three dots in a triangular orientation to represent a nose and eyes (Pair 2), and with the face pattern surrounded by an oval (Pair 3). In Experiment 1, the pigeons trained with Pair 1 were most accurate, those trained with Pair 2 were less so, and those trained with Pair 3 failed to acquire the discrimination within eighty 100-trial sessions. The same ordering was found in Experiment 2 for pigeons trained on the three pairs simultaneously. The authors suggest that a contrasting finding in humans, the face superiority effect, might be due to a gain in discriminability resulting from recognition of the pattern as a face. An exemplar model of information processing that excludes linguistic coding accounts for the present results.  相似文献   
70.
Kinetic knowledge is of great importance in achieving good control of the pyrolysis and gasification process and optimising system design. An overall kinetic pyrolysis scheme is therefore addressed here. The kinetic modelling incorporates the following basic steps: the degradation of the virgin biomass materials into primary products (tar, gas and semi-char), the decomposition of primary tar into secondary products and the continuous interaction between primary gas and char. The last step is disregarded completely by models in the literature. Analysis and comparison of predicted results from different kinetic schemes and experimental data on our fixed bed pyrolyser yielded very positive evidence to support our kinetic scheme. Project (No. 2001CB409600) Supported by the National Key Basic Research Program (973) of China  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