全文获取类型
收费全文 | 96891篇 |
免费 | 3990篇 |
国内免费 | 46篇 |
出版年
2020年 | 1127篇 |
2019年 | 1375篇 |
2018年 | 1959篇 |
2017年 | 1979篇 |
2016年 | 2062篇 |
2015年 | 1436篇 |
2014年 | 1748篇 |
2013年 | 8361篇 |
2012年 | 3194篇 |
2011年 | 3308篇 |
2010年 | 2003篇 |
2009年 | 2044篇 |
2008年 | 2959篇 |
2007年 | 2929篇 |
2006年 | 2601篇 |
2005年 | 2289篇 |
2004年 | 2319篇 |
2003年 | 2138篇 |
2002年 | 2118篇 |
2001年 | 3109篇 |
2000年 | 2966篇 |
1999年 | 2277篇 |
1998年 | 1165篇 |
1997年 | 998篇 |
1996年 | 1009篇 |
1995年 | 963篇 |
1994年 | 931篇 |
1993年 | 956篇 |
1992年 | 1829篇 |
1991年 | 1716篇 |
1990年 | 1704篇 |
1989年 | 1572篇 |
1988年 | 1542篇 |
1987年 | 1450篇 |
1986年 | 1469篇 |
1985年 | 1571篇 |
1984年 | 1273篇 |
1983年 | 1095篇 |
1982年 | 864篇 |
1979年 | 1300篇 |
1978年 | 968篇 |
1976年 | 848篇 |
1975年 | 1093篇 |
1974年 | 1216篇 |
1973年 | 1211篇 |
1972年 | 1056篇 |
1971年 | 945篇 |
1968年 | 1055篇 |
1967年 | 983篇 |
1966年 | 899篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
Psychological stress has been shown to affect immune system status and function, but most studies of this relationship have focused on acute stress and/or laboratory situations. The present study compared total numbers of leukocytes and lymphocyte subpopulations (determined by flow cytometry) and antibody titers to latent and nonlatent viruses among a group of chronically stressed individuals living near the damaged Three Mile Island (TMI) nuclear power plant with those of a demographically comparable control group. Urinary catecholamine and cortisol levels were also examined. Residents of the TMI area exhibited greater numbers of neutrophils, which were positively correlated with epinephrine levels. The TMI group also exhibited fewer B lymphocytes, T-suppressor/cytotoxic lymphocytes, and natural killer cells. Antibody titers to herpes simplex were significantly different across groups as well, whereas titers to nonlatent rubella virus as well as IgG and IgM levels were comparable. 相似文献
902.
Ms. Cherie Sutherland B.A. 《Journal of Near-Death Studies》1989,8(2):93-102
This study examines the incidence of reports of psychic phenomena and associated beliefs both before and after the near-death experience (NDE). The near-death experiencers interviewed reported no more psychic phenomena before the NDE than the general population. There was a statistically significant increase following the NDE in the incidence of 14 of 15 items examined. 相似文献
903.
904.
Dr. Juan C. Saavedra-Aguilar M.D. Lic. Juan S. Gómez-Jeria Lic.Q. 《Journal of Near-Death Studies》1989,7(4):265-272
This work has received financial support from FONDECYT (Project 1111-88). The authors also acknowledge the helpful comments of Dr. Bruce Cassels. 相似文献
905.
906.
On the development of procedural knowledge 总被引:30,自引:0,他引:30
D B Willingham M J Nissen P Bullemer 《Journal of experimental psychology. Learning, memory, and cognition》1989,15(6):1047-1060
Amnesic patients demonstrate by their performance on a serial reaction time task that they learned a repeating spatial sequence despite their lack of awareness of the repetition (Nissen & Bullemer, 1987). In the experiments reported here, we investigated this form of procedural learning in normal subjects. A subgroup of subjects showed substantial procedural learning of the sequence in the absence of explicit declarative knowledge of it. Their ability to generate the sequence was effectively at chance and showed no savings in learning. Additional amounts of training increased both procedural and declarative knowledge of the sequence. Development of knowledge in one system seems not to depend on knowledge in the other. Procedural learning in this situation is neither solely perceptual nor solely motor. The learning shows minimal transfer to a situation employing the same motor sequence. 相似文献
907.
Base-rate effects in category learning: a comparison of parallel network and memory storage-retrieval models 总被引:1,自引:0,他引:1
W K Estes J A Campbell N Hatsopoulos J B Hurwitz 《Journal of experimental psychology. Learning, memory, and cognition》1989,15(4):556-571
Exemplar-memory and adaptive network models were compared in application to category learning data, with special attention to base rate effects on learning and transfer performance. Subjects classified symptom charts of hypothetical patients into disease categories, with informative feedback on learning trials and with the feedback either given or withheld on test trials that followed each fourth of the learning series. The network model proved notably accurate and uniformly superior to the exemplar model in accounting for the detailed course of learning; both the parallel, interactive aspect of the network model and its particular learning algorithm contribute to this superiority. During learning, subjects' performance reflected both category base rates and feature (symptom) probabilities in a nearly optimal manner, a result predicted by both models, though more accurately by the network model. However, under some test conditions, the data showed substantial base-rate neglect, in agreement with Gluck and Bower (1988b). 相似文献
908.
Parts of visual objects: an experimental test of the minima rule 总被引:1,自引:0,他引:1
Three experiments were conducted to test Hoffman and Richards's (1984) hypothesis that, for purposes of visual recognition, the human visual system divides three-dimensional shapes into parts at negative minima of curvature. In the first two experiments, subjects observed a simulated object (surface of revolution) rotating about a vertical axis, followed by a display of four alternative parts. They were asked to select a part that was from the object. Two of the four parts were divided at negative minima of curvature and two at positive maxima. When both a minima part and a maxima part from the object were presented on each trial (experiment 1), most of the correct responses were minima parts (101 versus 55). When only one part from the object--either a minima part or a maxima part--was shown on each trial (experiment 2), accuracy on trials with correct minima parts and correct maxima parts did not differ significantly. However, some subjects indicated that they reversed figure and ground, thereby changing maxima parts into minima parts. In experiment 3, subjects marked apparent part boundaries. 81% of these marks indicated minima parts, 10% of the marks indicated maxima parts, and 9% of the marks were at other positions. These results provide converging evidence, from two different methods, which supports Hoffman and Richard's minima rule. 相似文献
909.
Potential for hostility and dimensions of anger 总被引:1,自引:0,他引:1
Recent reviews have linked Potential for Hostility derived from the Structured Interview (SI) to coronary artery disease, independent of the global Type A pattern. The present study examined the construct validity of Potential for Hostility ratings by correlating Potential for Hostility with 21 scales from four widely used anger/hostility measures: 7 scales from the Anger Self-Report, 8 scales from the Buss-Durkee Hostility Inventory, the total score from the Novaco Anger Inventory, and 5 scales from the Multidimensional Anger Inventory. The pattern of correlations revealed that Potential for Hostility was significantly related to scales reflecting awareness and arousal of anger, particularly the verbal expression of anger. To identify underlying anger dimensions, the 21 scales were factor-analyzed. Examination of two and three rotated principal components confirmed previous solutions. The first component, representing anger-arousing and -eliciting situations and anger awareness, was labeled Experience of Anger. The second component, consisting of scales dealing with either physical assault or verbal expression of anger, was labeled Expression of Anger. When a third factor was retained, it contained scales of suspicion, mistrust-suspicion, and guilt: It was therefore labeled Suspicion-Guilt. Potential for Hostility was correlated only with the Expression of Anger factor in the two-factor solution; in the three-factor solution, Potential for Hostility was correlated equally with the Experience of Anger and Expression of Anger factors but was not correlated with the Suspicion-Guilt factor. The implications of these results for the assessment of hostility are discussed. 相似文献
910.
J. Gayle Beck Heinrich Taegtmeyer M. Andrew Berisford Alixandre Bennett 《Journal of psychopathology and behavioral assessment》1989,11(3):209-220
Recent reports have indicated similarities between patients with persistent chest pain of nonorganic origin and patients with panic disorder. In order to explore this association further, we administered a structured interview and three self-report measures (State-Trait Inventory, Beck Depression Inventory, and SCL90-R) to three subject groups: (1) a sample with persistent chest pain (CP; n=14) who had been screened and found to have normal coronary arteries, (2) a sample of patients with panic disorder (PD; n=14), and (3) a sample of matched normals (n=14). CP patients were considered to be free of coronary artery disease (CAD) following normal cardiac catheterization and/or normal thallium stress tests and were not diagnosed initially with panic disorder. PD patients were diagnosed with a standardized psychiatric interview and were free of organic causes of panic. Using an exploratory data analytic approach, the results indicated that both CP and PD samples reported increased levels of state and trait anxiety (p <.0001), depression (p <.01), and somatization (p <.0001) compared with normals. CP patients differed from PD patients in their less frequent use of anxiolytic medication (p <.01) and lower levels of reported panic anxiety and phobic avoidance (p <.0001). These data suggest that persistent chest pain in the absence of CAD shares some features with panic disorder, yet differs from panic in key ways as well. The results are discussed in light of the role of anxiety in contributing to symptom labeling.This research was supported by Grant 86G-491 from the American Heart Association, Texas Affiliate, to J.G.B. H.T. is the recipient of USPHS Research Career Development Award K04-HL-0122246. 相似文献