全文获取类型
收费全文 | 33257篇 |
免费 | 1240篇 |
国内免费 | 18篇 |
出版年
2020年 | 320篇 |
2019年 | 440篇 |
2018年 | 597篇 |
2017年 | 654篇 |
2016年 | 606篇 |
2015年 | 450篇 |
2014年 | 513篇 |
2013年 | 2601篇 |
2012年 | 900篇 |
2011年 | 1033篇 |
2010年 | 680篇 |
2009年 | 669篇 |
2008年 | 935篇 |
2007年 | 874篇 |
2006年 | 820篇 |
2005年 | 700篇 |
2004年 | 654篇 |
2003年 | 692篇 |
2002年 | 643篇 |
2001年 | 1220篇 |
2000年 | 1195篇 |
1999年 | 867篇 |
1998年 | 392篇 |
1997年 | 324篇 |
1995年 | 334篇 |
1994年 | 328篇 |
1992年 | 736篇 |
1991年 | 719篇 |
1990年 | 673篇 |
1989年 | 631篇 |
1988年 | 598篇 |
1987年 | 592篇 |
1986年 | 564篇 |
1985年 | 626篇 |
1984年 | 497篇 |
1983年 | 396篇 |
1981年 | 323篇 |
1979年 | 483篇 |
1978年 | 359篇 |
1977年 | 342篇 |
1976年 | 319篇 |
1975年 | 425篇 |
1974年 | 421篇 |
1973年 | 482篇 |
1972年 | 383篇 |
1971年 | 320篇 |
1969年 | 329篇 |
1968年 | 381篇 |
1967年 | 335篇 |
1966年 | 386篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Seok -Man Kwon Larry Evans Tian P. S. Oei 《Journal of psychopathology and behavioral assessment》1990,12(4):365-374
This study examines the factor structure of the Mobility Inventory for Agoraphobia and attempts to validate the inventory, using an Australian sample of agoraphobic patients, by comparison with other scales. One hundred twentyfour panic disorder with agoraphobia patients were studied. Factor analysis showed that a two-factor solution was the most suitable both when subjects were accompanied (accompanied condition) and when alone (alone condition). Factor I represented public, crowded, or social situations including department stores, supermarkets, restaurants, theaters, and panics and social gatherings. Factor II reflected enclosed or riding situations such as elevators, parking garages, enclosed spaces, and riding in subways or airplanes. These two factors accounted for 46.6% and 44.3% of the variance on the accompanied condition and the alone condition, respectively. The Mobility Inventory was significantly correlated with the Agoraphobia factor of the Fear Questionnaire and the Social Avoidance and Distress scale. These results indicated that the Mobility Inventory is a valid instrument to measure agoraphobic behavior. 相似文献
992.
K. Blokker S. Bruin J. Bryden I. Houseman C. Okkerse C. Van der Meer A. P. Verkaik 《Knowledge, Technology, and Policy》1990,3(3):76-83
In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS).
Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as
cooperative unions and multinational companies are included. After considering the influence of the changing environment on
the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined.
Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and
what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences
with this strategic investment are evaluated. 相似文献
993.
994.
Emanuel L 《The Journal of clinical ethics》1990,1(4):289-290
The Hippocratic Oath has survived, with overriding power, the test of time. Written somewhere between 600 B.C. and 100 A.D., it addresses the intrinsic nature of medicine. Even those of us who know little of it or reject parts of it acknowledge it to be a symbol of the values of medicine. Such "canonization" is unlikely to be arbitrary; it is more likely that the oath strikes some key chord of truth. I suggest that it is its drive to the heart of medicine that makes the Hippocratic Oath inspiring today. 相似文献
995.
996.
Edward A. Wasserman Kim Kirkpatrick-Steger Linda J. Van Hamme Irving Biederman 《Psychological science》1993,4(5):336-341
Abstract— Two experiments investigated the role of spatial organisation in the discrimination and generalization of complex visual stimuli by pigeons. In Experiment 1, after pigeons had been trained to discriminate line drawings of four objects, they were tested with novel pictures in which the same component parts of the objects were spatially rearranged. The spatially scrambled pictures led to a dramatic drop in recognition accuracy, hut responding remained above chance. In Experiment 2, pigeons reached a high level of discriminative performance when required to choose among four different spatial arrangements of the same object parts. These results confirm Cerella's (1980) conclusion that pigeons discriminate the component parts of complex visual stimuli, but. unless it is assumed that the scrambling deleted or created emergent features, the results disconfirm his conclusion that spatial organization plays no role in pigeons' picture perception. 相似文献
997.
Depression in some patients with spinal cord injuries may be clinically significant and, when present, should be treated to
decrease morbidity including decreased physical functioning. Depression associated with spinal cord injury (SCI) may be misevaluated,
due to (1) nonspecific multifactorial production of depression symptoms and (2) SCI-specific decrease in somatic sensory central
nervous system input. The Somatic Suppression Hypothesis suggests that SCI patients have difficulty experiencing any intense
emotion because of suppression of physiological arousal. In addition, cognitive processes that may reduce depression in SCI
patients include: (1) attribution of somatic symptoms of depression to medical (biological) causes, (2) realistic, positive
expectations for physical improvement, and (3) the perception that the disability of the SCI is only minimally related to
the patient’s self-care after complete evaluation. Health personnel should accept lack of depression in SCI, and should encourage
positive realistic expectations of recovery. 相似文献
998.
999.
John W. Thomas Linda Bol Robert W. Warkentin Mark Wilson Amy Strage William D. Rohwer 《Applied cognitive psychology》1993,7(6):499-532
This investigation focused on the interrelationships among students' study activities, students' self-concept of academic ability ratings, students' academic achievement, and instructional practices in 12 high school biology courses. Using a framework derived from a previous investigation, course features were classified into those that appear to (a) place demands on, (b) support, or (c) compensate for student engagement in particular study activities. Students' study activities, self-concept of academic ability ratings, and achievement were measured with experimenter-developed instruments. Results are reported for (a) characteristics of instruments and course features, (b) relationships between central factors of the investigation, and (c) multi-level relationships between course features and student variables. Results at the student level indicated that self-concept of academic ability and, to a lesser extent, students' study activities were positively associated with student achievement. Students' self-concept of academic ability ratings were also linked to students' engagement in generative, proactive study activities. At the course level the supportive practices of providing challenging homework assignments and extensive feedback on student coursework were associated with student engagement in effortful, generative, proactive study activities. The provision of extensive feedback was also associated with high student achievement. Multi-level relationships were analysed using hierarchical linear modelling (HLM) analyses. These analyses revealed, for example, that in courses in which little or no feedback is given on homework assignments, the relationship between achievement and student engagement in diligent effort management activities was enhanced. Other HLM analyses were conducted to examine the mediating role of course features on the relationship between students' self-concept of academic ability and their study activities and achievement. For example, the presence of challenging course demands was associated with an enhancement of the relationship between self-concept of academic ability and achievement whereas the presence of instructor provisions (supports and compensations) designed to reduce course demands was associated with a reduction in this relationship. 相似文献
1000.
Glenn SS 《The Behavior analyst / MABA》1993,16(2):133-151
Behavior analysis is a cultural system of which the Association for Behavior Analysis is a component cultural system. As cultural systems, they are composed of interlocking behavioral contingencies that constitute their cultural practices. Critical to the survival of both cultural systems is the frequency of interaction with and the nature of the content of the behavioral contingencies composing those cultural practices. The strengths of behavior analysis as a cultural system include its disciplinary character and its worldwide community of scientists and practitioners; its ability to be integrated into a scientific worldview; its track record in providing effective solutions to problems of importance to society; and the high levels of intellect, competence, and commitment that are characteristic of its participants. Weaknesses of behavior analysis are its status as an academic orphan, its relatively small size and its underdeveloped professional identity, and a lack of sociopolitical sophistication among many of its members. Behavior analysis will need to maximize its strengths and mitigate its weaknesses if it is to take advantage of the many opportunities available for growth in the modern world. 相似文献