全文获取类型
收费全文 | 32383篇 |
免费 | 479篇 |
国内免费 | 38篇 |
专业分类
教育 | 22977篇 |
科学研究 | 3424篇 |
各国文化 | 250篇 |
体育 | 2265篇 |
综合类 | 44篇 |
文化理论 | 294篇 |
信息传播 | 3646篇 |
出版年
2022年 | 182篇 |
2021年 | 333篇 |
2020年 | 481篇 |
2019年 | 648篇 |
2018年 | 1006篇 |
2017年 | 1090篇 |
2016年 | 1082篇 |
2015年 | 672篇 |
2014年 | 858篇 |
2013年 | 5517篇 |
2012年 | 866篇 |
2011年 | 979篇 |
2010年 | 718篇 |
2009年 | 644篇 |
2008年 | 775篇 |
2007年 | 708篇 |
2006年 | 618篇 |
2005年 | 1144篇 |
2004年 | 938篇 |
2003年 | 717篇 |
2002年 | 616篇 |
2001年 | 631篇 |
2000年 | 589篇 |
1999年 | 562篇 |
1998年 | 294篇 |
1997年 | 342篇 |
1996年 | 357篇 |
1995年 | 279篇 |
1994年 | 293篇 |
1993年 | 256篇 |
1992年 | 437篇 |
1991年 | 399篇 |
1990年 | 421篇 |
1989年 | 430篇 |
1988年 | 400篇 |
1987年 | 328篇 |
1986年 | 339篇 |
1985年 | 411篇 |
1984年 | 336篇 |
1983年 | 337篇 |
1982年 | 253篇 |
1981年 | 265篇 |
1980年 | 233篇 |
1979年 | 327篇 |
1978年 | 275篇 |
1977年 | 246篇 |
1976年 | 208篇 |
1975年 | 173篇 |
1974年 | 173篇 |
1973年 | 194篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
941.
942.
INTRODUCTION It is well-known from the genetic code structure that there exists a connection between codons and physical and chemical amino acid properties (Lewin, 1983). Codon properties in turn are defined by physical properties of the nucleotides from which they are compounded (Ratner, 1985; 2000). The most important properties of nucleotides as complex three-dimensional molecules are their dipole moment, heat of formation and energy of the most stable con- formation (Schneider and Be… 相似文献
943.
Pigeons categorized binomial samples produced by two complementary random processes. Samples were 1, 2, 4, or 8 successively presented outcomes (vertical or horizontal lines) of, in effect, tossing one of two equally likely coins. One coin (A) was biased in favor of vertical, and the other coin (B) was similarly biased in favor of horizontal. Choosing red or green stimuli presented after each sample was reinforced with food if coin A or coin B had been tossed, respectively. In that sense, choosing red or green was logically analogous to inferring that the statistical evidence reflected tossing of coin A or coin B, respectively. The statistical diagnosticity of a sample, the relative likelihood of its having been produced by a particular coin, equaled, except for sampling fluctuation, the relative frequency of reinforcement of a particular color given that sample, and was experimentally varied by the bias on the coins and by sample size. All the variables that affect optimal, formal inference about binomial samples also affected intuitive inference. But inferences were very suboptimal: “undermatching” was obtained in part due to control of categorization by the sequential structure of binomial samples. These results reveal limitations of optimality theories for animal decision making in the face of uncertainty when observations in samples are presented successively. On the other hand, they are generally compatible with molecular analyses of instrumental learning which assign an important role to the local temporal organization of events preceding reinforcement. Most generally, they show that maladaptive control over intuitive statistical inference by a variable upon which optimal performance does not depend is neither a uniquely human phenomenon nor dependent upon linguistic strategies. 相似文献
944.
The results of recent studies into the use of the concept mapping heuristic seem to demonstrate that meaningful learning results through its use in science classrooms. While this underscores the need to use more effective instructional strategies in science teaching, the issue of the intervening variable of anxiety in learning and science achievement, and the possible use of a metacognitive strategy in anxiety reduction have not been addressed. This study, therefore, sought to find out if the metacognitive strategy of concept mapping reduces anxiety and thereby enhances achievement in biology. A total of 51 (30 boys, 21 girls) senior secondary one (grade 10) students participated in this experiment. Two instruments—the Zuckerman Affect Adjective Checklist and the Biology Achievement Test—were used in pre- and posttest administrations to measure the treatment effect on anxiety and achievement, respectively. Findings support the stand that concept mapping is significantly more effective than the traditional/expository teaching strategy in enhancing learning in biology. In addition, it apparently reduces students' anxiety towards the learning of biology. A significant reduction of anxiety was noticed for male subjects. 相似文献
945.
CONSTANTINE A. Papandreou DIONISIS X. Adamopoulos 《Education and Information Technologies》1997,2(3):207-218
This paper examines the influence of multimedia communication services in education and training. After a brief introduction in multimedia communication systems and an analysis of the learning process, a framework for the application of distributed, broadband multimedia communication services in education and training is proposed. Its main elements, which are a set of requirements, a generic layered model and a list of important related matters, are then discussed in considerable detail. Finally, the application of the proposed framework in the field of telecommunications training is suggested 相似文献
946.
Milam K. Freitag Jay Belsky Karin Grossmann Klaus E. Grossmann Hermann Scheuerer-Englisch 《Child development》1996,67(4):1437-1454
This cross-cultural study examined continuity in parent-child relationships from infancy to middle childhood in a sample of German families. Connections were traced between individual differences in a composite of markers of the parent-child attachment relationship system (including classification of the infant via the Strange Situation and parent via the Adult Attachment Interview and for mothers' ratings of sensitivity) and later parent-child communications. Fundings within the mother-child relationship revealed modest links between the composite and communications and were taken to suggest that the divergent fields of attachment and family communication research are addressing similar underlying relationship processes involving the interplay between relatedness and autonomy. Further findings revealed that the composite modestly predicted variability in children's competence in forming friendships and that differences in concurrent child-mother communications significantly added to and possibly mediated these effects. Results were interpreted as supporting a process model of development, whereby adaptation is influenced by both current and past relationship status. 相似文献
947.
Why do children learn in different ways: some are good students who show interest and zeal, while others are lazy and have to be taught against their will? Why do schools have over- and underachievers? Of course, there are a multitude of reasons. But almost 50 years ago it was shown using large data sets that families with high socioeconomic status are more likely to have children who are good students. Of course, there are many examples of successful students from poor families. However, they tend to be the exception to the rule. The certainty of success in school increases with rising socioeconomic status. 相似文献
948.
Theory Competition and the Process of Change 总被引:1,自引:0,他引:1
The reasons why many educational change initiatives have little impact are often framed in terms of either a poorly designed
process on the part of the change initiator, or in terms of problems with the attitudes, skills and/or knowledge of those
responsible for implementation. In this paper, we seek to integrate these two perspectives more closely by focusing on their
interface and the competing theories frequently held by the change initiators and implementers. This concept of theory competition
is illustrated with a case of a national literacy initiative in New Zealand in which the change initiators wished to raise
the achievement of low performing students through the development of “learning-centred” leadership in schools and evidence-based
practice. The desired outcomes were not achieved because theories about what it means to be a successful leader in such a
situation, the data needed to undertake the type of evidence-based analysis envisioned and school personnel beliefs about
the target students were understood differently by those responsible for initiating the change and those responsible for implementing
it. 相似文献
949.
950.
Pauline?A.?Porcaro Denise?E.?Jackson Patricia?M.?McLaughlin Cindy?J.?O’MalleyEmail authorView authors OrcID profile 《Journal of Science Education and Technology》2016,25(3):345-357
A common trend in higher education is the “flipped” classroom, which facilitates active learning during class. The flipped approach to teaching was instituted in a haematology ‘major’ class and the students’ attitudes and preferences for the teaching materials were surveyed. The curriculum design was explicit and involved four major components (1) the preparation of the students; (2) the weekly pre-class work; (3) the in-class active learning strategies and (4) closing the learning loop using formative quizzes. Each of these components is discussed in detail and was informed by sound pedagogical strategies. Several different sources of information and several freely available software tools to engage the students are discussed. Two iterations are reported here, with improved pass rate for the final examination from 47 to 48 % in the traditional class to 56–65 % in the flipped classroom approach. The majority of students (93 and 89 %) came to the class prepared, after viewing the screencasts and engaged fully with the activities within the face-to-face time. The students perceived that solving case studies (93 %) was the most beneficial activity for their learning and this was closely followed by the production of essay plans (71 %). The majority of students recommended that this approach be repeated the following year (69 and 75 %). 相似文献