全文获取类型
收费全文 | 21340篇 |
免费 | 260篇 |
国内免费 | 125篇 |
专业分类
教育 | 14907篇 |
科学研究 | 2416篇 |
各国文化 | 205篇 |
体育 | 1808篇 |
综合类 | 15篇 |
文化理论 | 224篇 |
信息传播 | 2150篇 |
出版年
2021年 | 174篇 |
2020年 | 360篇 |
2019年 | 498篇 |
2018年 | 633篇 |
2017年 | 615篇 |
2016年 | 611篇 |
2015年 | 386篇 |
2014年 | 494篇 |
2013年 | 3871篇 |
2012年 | 469篇 |
2011年 | 522篇 |
2010年 | 392篇 |
2009年 | 385篇 |
2008年 | 434篇 |
2007年 | 458篇 |
2006年 | 420篇 |
2005年 | 423篇 |
2004年 | 377篇 |
2003年 | 380篇 |
2002年 | 361篇 |
2001年 | 355篇 |
2000年 | 375篇 |
1999年 | 340篇 |
1998年 | 205篇 |
1997年 | 231篇 |
1996年 | 270篇 |
1995年 | 227篇 |
1994年 | 200篇 |
1993年 | 201篇 |
1992年 | 282篇 |
1991年 | 279篇 |
1990年 | 286篇 |
1989年 | 304篇 |
1988年 | 262篇 |
1987年 | 267篇 |
1986年 | 268篇 |
1985年 | 304篇 |
1984年 | 277篇 |
1983年 | 265篇 |
1982年 | 218篇 |
1981年 | 205篇 |
1980年 | 193篇 |
1979年 | 284篇 |
1978年 | 232篇 |
1977年 | 204篇 |
1976年 | 170篇 |
1975年 | 150篇 |
1974年 | 163篇 |
1973年 | 139篇 |
1971年 | 127篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
941.
942.
Leslie D. Leve David C. R. Kerr Daniel Shaw Xiaojia Ge Jenae M. Neiderhiser Laura V. Scaramella John B. Reid Rand Conger David Reiss 《Child development》2010,81(1):340-356
To further the understanding of the effects of early experiences, 9-month-old infants were observed during a frustration task. The analytical sample was composed of 348 linked triads of participants (adoptive parents, adopted child, and birth parent[s]) from a prospective adoption study. It was hypothesized that genetic risk for externalizing problems and affect dysregulation in the adoptive parents would independently and interactively predict a known precursor to externalizing problems: heightened infant attention to frustrating events. Results supported the moderation hypotheses involving adoptive mother affect dysregulation: Infants at genetic risk showed heightened attention to frustrating events only when the adoptive mother had higher levels of anxious and depressive symptoms. The Genotype × Environment interaction pattern held when substance use during pregnancy was considered. 相似文献
943.
Traditionally the kinetics of a chemical reaction has been studied as a set of coupled ordinary differential equations. The law of mass action, a tried and tested principle for reactions involving macroscopic quantities of reactants, gives rise to deterministic equations in which the variables are species concentrations. In recent years, though, as smaller and smaller systems – such as an individual biological cell, say – can be studied quantitatively, the importance of molecular discreteness in chemical reactions has increasingly been realized. This is particularly true when the system is far from the ‘thermodynamic limit’ when the numbers of all reacting molecular species involved are several orders of magnitude smaller than Avogadro’s number. In such situations, each reaction has to be treated as a probabilistic ‘event’ that occurs by chance when the appropriate reactants collide. Explicitly accounting for such processes has led to the development of sophisticated statistical methods for simulation of chemical reactions, particularly those occurring at the cellular and sub-cellular level. In this article, we describe this approach, the so-called stochastic simulation algorithm, and discuss applications to study the dynamics of model regulatory networks. 相似文献
944.
Lawrence GR Gottwald VM Hardy J Khan MA 《Research quarterly for exercise and sport》2011,82(3):431-441
In the current experiment, we examined optimal focus for novices during a movement sequence in which performance was measured on accurate movement form/technique. A novel gymnastics routine was practiced under either an internal skill-relevant, internal skill-irrelevant, external, or no attention focus. Retention and transfer tests were then completed. During acquisition, adopting an internal irrelevant focus significantly improved performance, whereas an external focus degraded performance. There were no significant group differences in the retention and transfer tests. This suggests that learning of movement form/technique did not benefit from a specific focus of attention. The results are interpreted via an attentional capacity viewpoint and the notion that form tasks do not always contain obvious movement effects central to common coding and the constrained action hypothesis. 相似文献
945.
Francis A. Mcguire Brian J. Mihalik James R. Pope Jr. 《Research quarterly for exercise and sport》2013,84(3):291-293
Abstract Students (N = 104) enrolled in four low fitness, one middle fitness, and one high fitness class in basic physical education classes at the University of Connecticut participated in a 4-week program of isometric exercises done with an adjustable nylon belt which was stabilized against various body segments. Low, middle, and high fitness classes were compared in the amount of improvement made in the 5 items in which significant gains had been made. The MWF classes which did 30 min. of isometric exercises for 12 class meetings were compared to the TTh classes which met for 8 class meetings and which did the same isometric exercise program and in addition did stretching exercises and ran a mile. When all groups were treated together, mean gains of 1.1 in. in the vertical jump, .74 sec. in the agility run, .17 sec. in the 30-yd. dash, 151.9 lb. in the leg lift, and 57.0 lb. in the back lift were made. These were all significant at the 0.005 to the 0.0005 level. Small but significant gains were made in right and left grip, the Fait endurance hang, and the 380-yd. run. The low fitness classes made greater improvements in the leg lift, the vertical jump, and the agility run than did the middle or high fitness groups. The high fitness class made greater improvements in the back lift and in the 30-yd. dash than did the low or middle fitness classes. The classes which did only isometric exercises for a half-hour three times each week for 4½ weeks made greater mean gains in the vertical jump, the agility run, the 30-yd. dash and the back lift than did the classes which met for 60-min. periods twice each week for 4½ weeks and did stretching exercises and running in addition to the isometric exercises. However, the latter made greater gains in the leg lift. 相似文献
946.
J. Fredericks Volkwein Lisa R. Lattuca Betty J. Harper Robert J. Domingo 《Research in higher education》2007,48(2):251-282
This research uses a conceptual model to examine the influence of a change in accreditation standards on a representative
national sample of 203 engineering programs at 40 institutions. Based on data collected from more than 140 program chairs,
1,200 faculty, 4,300 graduates of 2004, and 5,400 graduates of 1994, the study investigates the differential impact of the
change in accreditation standards on programs reviewed in different years during the period of transition. Despite significant
variation across most of the measures and groups in 1994 (before the introduction of the new accreditation criteria), the
2004 evidence demonstrates a surprisingly uniform level of student experiences and outcomes. These findings suggest that engineering
accreditation is beginning to accomplish its quality assurance goals.
This is a revised version of a research paper presented at the meeting of the Association for Institutional Research, May
17, 2006, Chicago, IL. 相似文献
947.
Metacognition and self-regulation are important for developing effective learning in the classroom and beyond, but novice learners often lack effective metacognitive and self-regulatory skills. However, researchers have demonstrated that metacognitive processes can be developed through practice and appropriate scaffolding. Betty’s Brain, an open-ended computer-based learning environment, helps students practice their cognitive skills and develop related metacognitive strategies as they learn science topics. In this paper, we analyze students’ activity sequences in a study that compared different categories of adaptive scaffolding in Betty’s Brain. The analysis techniques for measuring students’ cognitive and metacognitive processes extend our previous work on using sequence mining methods to discover students’ frequently-used behavior patterns by (i) developing a systematic approach for interpreting derived behavior patterns using a cognitive/metacognitive task model and (ii) analyzing the evolution of students’ frequent behavior patterns over time. Our results show that it is possible to identify students’ learning behaviors and analyze their evolution as they work in the Betty’s Brain environment. Further, the results illustrate that changes in student behavior were generally consistent with the scaffolding provided, suggesting that these metacognitive strategies can be taught to middle school students in computer-based learning environments. 相似文献
948.
Gary R. Pike 《Research in higher education》1991,32(5):499-524
Calls for accountability, coupled with a desire to improve teaching and learning, have prompted many colleges and universities to consider ways of assessing the effects of postsecondary education on student growth and development. Despite widespread support for the concept of assessing student change, relatively few institutions have implemented this type of assessment, in part because of a concern about the best method of measuring change. This article describes the use of structural equation models with latent variables to assess the effects of education on change. Advantages of using structural equation models with latent variables include error-free measurement of change, direct tests of the assumptions underlying change research, along with the power and flexibility of maximum likelihood estimation. An analysis of data on freshman-to-senior gains provides evidence of the advantages of latent variable structural equation modeling and also suggests that the group differences identified by traditional analysis of variance and covariance techniques may be an artifact of measurement error. 相似文献
949.
This article explores how innovations in the funeral industry borrow from the technological affordances, commercial logics, cultural norms, and affective registers of social media platforms. Based on ethnographic research of funeral industry conventions, we analyze examples of funeral planning tools, funeral service mediation, and digital memorialization products. We consider how these products aim to capture forms of data, affect, and value as part of the funeral industry’s efforts to shore up their historically intermediary relevance in the face of potential “disruption” from technological innovation, and threats of marginalization posed by shifting norms of networked grieving and commemoration in digital culture 相似文献
950.
Alexander J. Carroll Kevin Michael Klipfel 《The Journal of Academic Librarianship》2019,45(2):110-118
When myths become canonical beliefs within a professional culture, they can have a profound impact on professional practice. In this paper we identify as a pernicious educational myth the belief that the ability to teach well is a naturally occurring innate talent or skill. The first two sections of the paper aim to demonstrate (i) that the concept of the naturally gifted teacher is a myth based on factually incorrect assumptions about expertise development and (ii) that this myth has several major negative implications for professional practices around teaching in academic libraries. We then we draw on the education literature to offer an alternative model for the cultivation of teaching excellence, an instructional design/action research framework that prioritizes ‘deliberative’ practice over innate talent. We close with suggestions for how academic librarians and library administrators can implement this framework within their institutions. 相似文献