全文获取类型
收费全文 | 11847篇 |
免费 | 256篇 |
国内免费 | 192篇 |
专业分类
12295篇 |
出版年
2015年 | 39篇 |
2013年 | 38篇 |
2012年 | 982篇 |
2011年 | 1160篇 |
2010年 | 282篇 |
2009年 | 135篇 |
2008年 | 927篇 |
2007年 | 923篇 |
2006年 | 819篇 |
2005年 | 725篇 |
2004年 | 616篇 |
2003年 | 612篇 |
2002年 | 543篇 |
2001年 | 352篇 |
2000年 | 502篇 |
1999年 | 220篇 |
1998年 | 78篇 |
1997年 | 57篇 |
1996年 | 79篇 |
1995年 | 43篇 |
1994年 | 77篇 |
1993年 | 118篇 |
1992年 | 99篇 |
1991年 | 106篇 |
1990年 | 98篇 |
1989年 | 100篇 |
1988年 | 114篇 |
1987年 | 128篇 |
1986年 | 90篇 |
1985年 | 120篇 |
1984年 | 121篇 |
1983年 | 139篇 |
1982年 | 95篇 |
1981年 | 92篇 |
1980年 | 79篇 |
1979年 | 88篇 |
1978年 | 75篇 |
1966年 | 48篇 |
1965年 | 133篇 |
1964年 | 105篇 |
1963年 | 126篇 |
1962年 | 54篇 |
1958年 | 145篇 |
1957年 | 116篇 |
1956年 | 89篇 |
1955年 | 58篇 |
1954年 | 49篇 |
1953年 | 54篇 |
1951年 | 41篇 |
1950年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
241.
在临床和实验研究文献中有大量的关于应激原影响免疫功能的描述性研究。虽然所观察到的改变与感染,新生物和自身免疫疾病的发病、病程和结果有关,但它们间是怎样的关系并不很清楚。尽管并不怀疑应激可能影响不同的免疫反应,但应激是通过什么机制改变淋巴和脊髓细胞的功能的,以及这些细胞为什么对应激的调节物质是敏感的,一直是模糊不清的。现在这些情况迅速改变了,有证据表明免疫系统对应激的敏感性并非偶然。在脑和免疫系统间存在着相互调制的作用。 相似文献
242.
本文为1985年6月14日在授予P.里克尔黑格尔奖时在斯图加特发表的演讲,论述里克尔的哲学思想在当代哲学思潮中的发展。 相似文献
243.
次协调逻辑(para-consistent logic)是那些把有意义的不协调理论形式化的逻辑。另一方面,辩证逻辑是把建立在黑格尔、马克思及其后继者提出的观念、原则之上的理论形式化的逻辑。这样的学科与次协调逻辑是相互交叉的。 相似文献
244.
245.
Moore J 《Journal of the experimental analysis of behavior》1982,37(1):115-122
Pigeons chose between equivalent two-component mixed and multiple terminal-link schedules of reinforcement in the concurrent-chains procedure. The pigeons preferred the multiple schedule over the mixed when the components of the compound schedules were differentiated in terms of density of reinforcement, but the pigeons were indifferent when the components were differentiated in terms of number of reinforcers per cycle. Taken together, these results indicate that a local variable, the interval to the first reinforcer, but not a molar variable, the number of reinforcers, was sufficient to differentiate the components and thereby evoke preference. 相似文献
246.
Smith BM Schumaker JB Schaeffer J Sherman JA 《Journal of applied behavior analysis》1982,15(1):97-110
An experiment was conducted to evaluate procedures to improve classroom discussions in seventh-grade social studies classes. An increased number of students participated in discussions when rules were stated for discussions, students were praised for their contributions, the teacher restated or paraphrased students' contributions aloud or on the blackboard, the teacher planned an outline of discussion questions, student contributions to discussions were recorded and were used to determine part of the students' grades for the class, and discussion grades were publicly posted.The second part of the study focused on procedures designed to improve quality of classroom discussions. Students were taught to participate in discussions by providing reasons for their statements, comparisons between different points, or examples supporting their statements. As each type of contribution was taught, recorded, and counted toward part of the students' classroom grades, each type of contribution increased. Ratings of discussions by outside judges consisting of junior high school teachers, junior high school students, and persons experienced in conducting discussions, indicated that the training increased the overall quality of the discussions. Use of the quality training procedures, however, resulted in decreased levels of overall participation in discussion, a decrease that was reversed by the use of a group contingency for participation. Finally, the discussions after training seemed to be preferred by both the teacher and the students. 相似文献
247.
Changes in a multiple-response repertoire during response-contingent punishment and response restriction: Sequential relationships 下载免费PDF全文
A multiple-response baseline of four activities was established using gerbils as subjects. When one of the baseline responses was punished (Experiment 1) or restricted (Experiments 2 and 3), only the most probable of the alternative baseline responses increased. The response most likely to follow the punished or restricted responses during baseline sessions was also suppressed during subsequent punishment or response-restriction treatment. 相似文献
248.
249.
250.
在苏联,由于经济和社会关系的伟大革命改造,建成了发达的社会主义社会。苏联的生活方式决定了社会意识的普遍无神论化,因此,在苏联社会生活中,科学无神论的社会功能和文化功能得以充实和扩大,科学无神论同物质和精神实践的各方面、各领域的联系得以巩固和完善。在信教者中间,虔诚狂热的信徒逐渐减少,这类现象证明,宗教在我国社会中的影响正在减退。 相似文献