全文获取类型
收费全文 | 16781篇 |
免费 | 189篇 |
国内免费 | 7篇 |
专业分类
教育 | 12141篇 |
科学研究 | 1722篇 |
各国文化 | 80篇 |
体育 | 1192篇 |
综合类 | 14篇 |
文化理论 | 148篇 |
信息传播 | 1680篇 |
出版年
2021年 | 118篇 |
2020年 | 155篇 |
2019年 | 259篇 |
2018年 | 402篇 |
2017年 | 454篇 |
2016年 | 491篇 |
2015年 | 314篇 |
2014年 | 327篇 |
2013年 | 2638篇 |
2012年 | 443篇 |
2011年 | 520篇 |
2010年 | 303篇 |
2009年 | 245篇 |
2008年 | 386篇 |
2007年 | 288篇 |
2006年 | 346篇 |
2005年 | 859篇 |
2004年 | 648篇 |
2003年 | 468篇 |
2002年 | 342篇 |
2001年 | 383篇 |
2000年 | 317篇 |
1999年 | 283篇 |
1998年 | 132篇 |
1997年 | 160篇 |
1996年 | 176篇 |
1995年 | 178篇 |
1994年 | 140篇 |
1993年 | 162篇 |
1992年 | 235篇 |
1991年 | 210篇 |
1990年 | 209篇 |
1989年 | 244篇 |
1988年 | 245篇 |
1987年 | 208篇 |
1986年 | 204篇 |
1985年 | 216篇 |
1984年 | 189篇 |
1983年 | 229篇 |
1982年 | 170篇 |
1981年 | 159篇 |
1980年 | 156篇 |
1979年 | 229篇 |
1978年 | 181篇 |
1977年 | 164篇 |
1976年 | 151篇 |
1975年 | 128篇 |
1974年 | 119篇 |
1973年 | 125篇 |
1971年 | 106篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
The purpose of the study was to examine the relationship of classroom environment to attitudes toward science and achievement in science among tenth grade biology students. An attitude instrument was administered at three times during the school year to measure student attitudes toward science and the classroom environment. The classroom environment measures examined six areas: emotional climate of the science classroom, science curriculum, physical environment of the science classroom, science teacher, other students in the science classroom, and friends attitudes toward science. Student achievement in science was measured by teacher reported semester grades. The results of the study indicated: (1) student attitudes toward the classroom environment predicted between 56 to 61% of the variance in attitudes toward science, (2) student attitudes toward the classroom environment predicted between 5 to 14% of the variance in achievement in science, (3) student attitudes toward science and attitudes toward the classroom environment predicted between 8 and 18% of the variance in achievement in science. 相似文献
152.
Five suburban community colleges in a metropolitan area collaborated on a survey to parents of high school graduates of the class of 2002 who attended the colleges in fall 2002. The study was undertaken to learn more about parents roles in their students selection of community colleges, to give insights and information about this important community college constituency, and to assist community colleges to shape more effective ways to foster positive and supportive opinions among parents of potential students. Parents want the community college to provide students with credits and grade point averages enabling transfer, overestimate their students academic skills as measured by course placement tests, engaged in a number of college-choice activities, and indicate that factors associated with lifestyle and money were major reasons for selecting the community college. Associations between parents social capital and perceptions of their students academic abilities were found for a number of dependent variables examined. The study also revealed important differences in how participating institutions record and calculate key measures such as credits earned and grade point averages. 相似文献
153.
1 Introduction Duringthe past several decades ,considerable atten-tion has been given to devising methods for solvingconstrained opti mization problemsviaunconstrainedmini mization techniques and a number of researchwork in the area of nonlinear programmi… 相似文献
154.
155.
There is an ongoing debate in the student evaluation of teaching literature about whether an overall rating or factorial dimensions of teaching effectiveness should be used in personnel decisions. Marsh and his colleagues have advocated the use of a weighted average approach to computing overall evaluations. A policy-capturing experiment was carried out where students in three different instructional contexts made overall evaluations of hypothetical instructors based on a manipulation of the teaching factors in Marsh's SEEQ. The results indicated (1) amount learned was consistently the most important factor affecting overall evaluations; (2) course difficulty was consistently the least important factor affecting overall evaluations; and (3) there was a strong similarity among the three groups in the relative importance of the various teaching factors in arriving at an overall evaluation. The implications of this research are discussed, as well as directions for future research. 相似文献
156.
When identifyinginstruments that have had great influence on the history of physics, none comes to mind more quickly than the pendulum. Though first treated scientifically by Galileo in the 16th century, and in some respects nearly `dead' by the middle of the 20th century; the pendulum experienced `rebirth' by becoming an archetype of chaos. With the resulting acclaim for its surprising behavior at large amplitudes, one might expect that there would already be widespread interest in another of its significant nonlinearities. Such is not the case, however, and the complex motions of small amplitude physical pendula are barely known. The present paper shows that a simply-constructed metallic rod pendulum is capable of demonstrating rich physics in a largely unstudied area. 相似文献
157.
学习“三个代表”的重要思想 ,必须坚持理论联系实际的马克思主义学风。要深入把握“三个代表”重要思想的理论根据和实践根据 ,更要研究怎样切实有效地实践“三个代表”。 相似文献
158.
159.
160.
The paper describes the design and use of a studio system which arose out of the need to give demonstrations of experimental procedures to practical classes of up to 150 students. Since the requirements could be specified in some detail it was possible to use novel methods of working which turned out to be very efficient and economical. 相似文献