全文获取类型
收费全文 | 23465篇 |
免费 | 169篇 |
国内免费 | 1篇 |
专业分类
23635篇 |
出版年
2024年 | 9篇 |
2023年 | 41篇 |
2022年 | 33篇 |
2021年 | 58篇 |
2020年 | 70篇 |
2019年 | 114篇 |
2018年 | 3568篇 |
2017年 | 2913篇 |
2016年 | 2350篇 |
2015年 | 295篇 |
2014年 | 176篇 |
2013年 | 444篇 |
2012年 | 757篇 |
2011年 | 2553篇 |
2010年 | 2610篇 |
2009年 | 1547篇 |
2008年 | 1833篇 |
2007年 | 2297篇 |
2006年 | 132篇 |
2005年 | 347篇 |
2004年 | 286篇 |
2003年 | 224篇 |
2002年 | 154篇 |
2001年 | 87篇 |
2000年 | 111篇 |
1999年 | 53篇 |
1998年 | 49篇 |
1997年 | 35篇 |
1996年 | 34篇 |
1995年 | 22篇 |
1994年 | 13篇 |
1993年 | 22篇 |
1992年 | 23篇 |
1991年 | 28篇 |
1990年 | 40篇 |
1989年 | 18篇 |
1988年 | 28篇 |
1987年 | 22篇 |
1986年 | 25篇 |
1985年 | 21篇 |
1984年 | 23篇 |
1983年 | 19篇 |
1982年 | 9篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1974年 | 8篇 |
1971年 | 8篇 |
1966年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Escape and avoidance that are disproportional to the danger of the pertinent stimulus are important clinical problems that are often related to inaccurate (catastrophic) expectations. One possible source of such expectations is a prior, underestimated aversive experience. In the present experiment the hypotheses that underestimated pain leads to escape and that it leads to avoidance were tested. In order to control for the effect of the intensity of the pain stimulus, a control group that received 20 pain stimuli of high intensity was formed. Subjects in the experimental condition received 17 pain stimuli of low intensity and 3 of (unexpectedly) high intensity (experimentally induced underprediction). Underprediction of the high intensity stimulus was significantly related to escape, but not to avoidance. The results suggest that the way in which avoidance was operationalized accounts for this. The strong support of the hypothesized relationship between underpredicted pain and escape is an important finding, however. 相似文献
42.
Rodger Beehler 《Studies in Philosophy and Education》1990,10(4):315-335
The essay examines the argument advanced by E.D. Hirsch, Jr., for instituting ‘cultural literacy’ as a fundamental priority of schools. A number of confusions and equivocations in Hirsch's reasoning are identified, and the propensity of his project to indoctrinate is exposed. Among the features of Hirsch's argument shown to be troubling are his shifting construal of ‘language’, his inconsistency about the requirements of cultural literacy, and his uncritical relation to traditional images of the American past and present. The upshot is to raise the question why Hirsch's project has elicited wide support and praise. 相似文献
43.
This case study concerns an 18-year-old bilingual girl who suffered a radiation lesion in the left (dominant) thalamic and temporal region when she was 4 years old. Language and memory assessment revealed deficits in auditory short-term memory, auditory word comprehension, nonword repetition, syntactic processing, word fluency, and confrontation naming tasks. Both languages (English and Dutch) were found to be affected in a similar manner, despite the fact that one language (English) was acquired before and the other (Dutch) after the period of lesion onset. Most of the deficits appear to be related to verbal (short-term) memory dysfunction. Several hypotheses of subcortical involvement in memory processes are discussed with reference to existing theories in this area. 相似文献
44.
Transparent layer constancy 总被引:1,自引:0,他引:1
W Gerbino C I Stultiens J M Troost C M de Weert 《Journal of experimental psychology. Human perception and performance》1990,16(1):3-20
Perceived transparency was studied as a constancy problem. In the episcotister (E-) model of scission, luminances are partitioned into layer and background components; four luminances determine values of two layer parameters that specify constancy of a transparent layer on different backgrounds. The E-model was tested in an experiment in which 12 Ss matched 24 pairs of four-luminance patterns by adjusting two luminances of the comparison pattern. Both the standard and the comparison were perceived as a transparent layer on a checkerboard. The E-model predicts matches when layer values are identical in the two patterns. One parameter was constant, constraining the adjustment along the second dimension. Obtained values corresponded well with E-predictions. Alternative models based on local luminance or average contrast ratios accounted for less variability. Results indicate that transparency models should utilize luminance, not reflectance, as the independent variable. 相似文献
45.
Molecular sequence data, made available in the last 15 years or so, have led to the classification of living cells into three phylogenetic domains: Bacteria, Archaea, and Eucarya. All the organisms that have been tested belonging to either domain were capable of mounting a stress response with essentially the same characteristics, regardless of the stressor. The protagonists in the cell's stress response are the stress genes and their protein products. Some of the latter are molecular chaperones. Under physiological conditions, these chaperones aid other cellular proteins to fold properly and achieve a native -functional- configuration, and to translocate from the place of synthesis to the cell's locale in which they will operate. In a stressed cell, the stress proteins that are chaperones protect other molecules from denaturation and help those partially damaged to regain a functional configuration. Thus, cell death is avoided and recovery is enhanced. The study of stress genes and proteins has progressed considerably in organisms belonging to the domains Bacteria and Eucarya. Less is known about the archaeal stress genes. Here, research with an organism from the Archaea is discussed, focusing on the stress genes of the hsp70 (dnaK) locus. Future perspectives for basic and applied research within the health sciences and biotechnology industries are presented. 相似文献
46.
47.
Jörg R. J. Schirra 《Kognitionswissenschaft》1997,6(4):177-195
How can we explain that an assertion on something perceived can be understood in the same manner by somebody who cannot perceive that scene? This problem bases the interest in computational linguistics in how listener modeling could possibly be harmonized with reference semantics. Mental images substituting real perception appear as a way out. The architecture of the listener model has to be adapted to the creation and use of such pictorial data structures. Furthermore, the relation between the latter and a verbal (i. e., propositional) representation must be understood. The resulting architecture of a listener model with reference semantics can be employed to solve communicational problems from three general classes in a better way, as is demonstrated by an example implementation. 相似文献
48.
W. M. de Muynck 《Synthese》1995,102(2):293-318
The axiomatic approaches of quantum mechanics and relativity theory are compared with approaches in which the theories are thought to describe readings of certain measurement operations. The usual axioms are shown to correspond with classes of ideal measurements. The necessity is discussed of generalizing the formalisms of both quantum mechanics and relativity theory so as to encompass more realistic nonideal measurements. It is argued that this generalization favours an empiricist interpretation of the mathematical formalisms over a realist one. 相似文献
49.
MENSTRUAL JOY The Construct and Its Consequences 总被引:1,自引:0,他引:1
Joan C. Chrisler Ingrid K. Johnston Nicole M. Champagne Kathleen E. Preston 《Psychology of women quarterly》1994,18(3):375-387
Fifty female college students participated in a study of women's health. In a counterbalanced design, half of the participants completed the Menstrual Joy Questionnaire (MJQ) and the Menstrual Attitude Questionnaire (MAQ) in the first testing session. A week later they completed the Menstrual Distress Questionnaire (MDQ) and the Menstrual Attitude Questionnaire. The other participants completed the MDQ and MAQ in the first session and the MJQ and MAQ in the second. A multivariate analysis of variance revealed that those who received the MJQ first reported more positive cyclic changes on the MDQ and more positive attitudes on the MAQ. A follow-up study of 40 college students examined their responses to the MJQ. Participants reported that they were surprised or incredulous; most had not previously considered positive aspects of the menstrual cycle. Thirty percent reported that the MJQ had caused them to look at menstruation in a different way. 相似文献
50.