首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   10329篇
  免费   1264篇
  国内免费   693篇
  2024年   38篇
  2023年   218篇
  2022年   206篇
  2021年   269篇
  2020年   536篇
  2019年   492篇
  2018年   466篇
  2017年   479篇
  2016年   425篇
  2015年   354篇
  2014年   400篇
  2013年   1189篇
  2012年   277篇
  2011年   426篇
  2010年   319篇
  2009年   443篇
  2008年   480篇
  2007年   521篇
  2006年   517篇
  2005年   429篇
  2004年   395篇
  2003年   312篇
  2002年   266篇
  2001年   187篇
  2000年   164篇
  1999年   173篇
  1998年   140篇
  1997年   139篇
  1996年   100篇
  1995年   107篇
  1994年   103篇
  1993年   86篇
  1992年   75篇
  1991年   52篇
  1990年   49篇
  1989年   44篇
  1988年   35篇
  1987年   50篇
  1986年   34篇
  1985年   165篇
  1984年   160篇
  1983年   137篇
  1982年   121篇
  1981年   98篇
  1980年   101篇
  1979年   93篇
  1978年   121篇
  1977年   105篇
  1976年   82篇
  1975年   56篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
221.
Let S be a deductive system such that S-derivability (s) is arithmetic and sound with respect to structures of class K. From simple conditions on K and s, it follows constructively that the K-completeness of s implies MP(S), a form of Markov's Principle. If s is undecidable then MP(S) is independent of first-order Heyting arithmetic. Also, if s is undecidable and the S proof relation is decidable, then MP(S) is independent of second-order Heyting arithmetic, HAS. Lastly, when s is many-one complete, MP(S) implies the usual Markov's Principle MP.An immediate corollary is that the Tarski, Beth and Kripke weak completeness theorems for the negative fragment of intuitionistic predicate logic are unobtainable in HAS. Second, each of these: weak completeness for classical predicate logic, weak completeness for the negative fragment of intuitionistic predicate logic and strong completeness for sentential logic implics MP. Beth and Kripke completeness for intuitionistic predicate or sentential logic also entail MP.These results give extensions of the theorem of Gödel and Kreisel (in [4]) that completeness for pure intuitionistic predicate logic requires MP. The assumptions of Gödel and Kreisel's original proof included the Axiom of Dependent Choice and Herbrand's Theorem, no use of which is explicit in the present article.  相似文献   
222.
Changeover behavior and preference in concurrent schedules   总被引:2,自引:2,他引:0       下载免费PDF全文
Pigeons were trained on a multiple schedule of reinforcement in which separate concurrent schedules occurred in each of two components. Key pecking was reinforced with milo. During one component, a variable-interval 40-s schedule was concurrent with a variable-interval 20-s schedule; during the other component, a variable-interval 40-s schedule was concurrent with a variable-interval 80-s schedule. During probe tests, the stimuli correlated with the two variable-interval 40-s schedules were presented simultaneously to assess preference, measured by the relative response rates to the two stimuli. In Experiment 1, the concurrently available variable-interval 20-s schedule operated normally; that is, reinforcer availability was not signaled. Following this baseline training, relative response rate during the probes favored the variable-interval 40-s alternative that had been paired with the lower valued schedule (i.e., with the variable-interval 80-s schedule). In Experiment 2, a signal for reinforcer availability was added to the high-value alternative (i.e., to the variable-interval 20-s schedule), thus reducing the rate of key pecking maintained by that schedule but leaving the reinforcement rate unchanged. Following that baseline training, relative response rates during probes favored the variable-interval 40-s alternative that had been paired with the higher valued schedule. The reversal in the pattern of preference implies that the pattern of changeover behavior established during training, and not reinforcement rate, determined the preference patterns obtained on the probe tests.  相似文献   
223.
Mothers of problem and nonproblem toddlers rated videotapes of their own and unfamiliar children's behavior. They classified the behaviors as positive, negative, or neutral, and evaluated the intensity of the positive or negative behaviors. Ratings did not differ by problem status; however, all mothers classified their own children's behavior as less negative than did an independent observer. Mothers also evaluated all children's negative behavior as less aversive than did the observer. Finally, mothers mistakenly classified less of their own children's behavior as negative and more as positive when compared to their biases in classifying unfamiliar children's behavior.  相似文献   
224.
This study examined the effect of parental distress on mothers' and fathers' reports of children's emotional and behavioral problems. The subjects were the parents of 696 children aged 10 to 11 or 14 to 15 years living in two-parent families in the community. The study utilized an extended version of the model previously employed by Fergusson, Lynskey, and Horwood (1993) to examine the impact of maternal depression on mothers' reports of children's behavior. In the present study, the extended model was used to assess the impact of distress on reports of childhood externalizing and internalizing problems obtained from both mothers and fathers. The results suggested that distress had little influence on mothers' or fathers' reports of childhood behavior problems. It is concluded that in community studies the size of any bias in mothers' and fathers' reports of childhood behavior problems due to parental distress is likely to be very small and of little clinical significance.  相似文献   
225.
In this paper, it is proposed that a) psychosocial medicine is best taught in a setting that provides technical and emotional support, while seizing for teaching only those moments when the learner is most receptive; and b) that the setting should avoid the development of a separate psychosocial skills curriculum, but should take the student where he or she is and integrate the psychosocial skills into his or her everyday biomedical practice. The paper gives specific case examples in which family based psychosocial issues were preeminent in the clinical problem-solving medical residents faced.  相似文献   
226.
The MRG was published 1988 in order to support developments in group psychotherapy methods as one of the all too few process observation research methods for studying group-as-a-whole. After 9 years of what pilot studies have labeled successful clinical trials, this study aims at validating the MRG against the established SAVI: Structural Analysis of Verbal Interaction (Agazarian & Simon 1989). Videotaped group sessions from short-term groups for alcohol dependent patients conducted along two therapy methods, one behaviorally oriented and the other group analytic, are used as material. The MRG is validated in the study, confirmed to be clinically valuable, and some interesting comparisons between the two treatment modalities are also made.  相似文献   
227.
语句重音分布模式知觉   总被引:1,自引:1,他引:0  
杨玉芳 《心理学报》1996,29(3):225-231
在排除语义和句法结构信息的情况下,用统计方法研究听者使用局部的韵律学线索知觉语句重音分布模式的能力;并根据知觉模式,讨论汉语中重音分类、词重音在语流中的变化以及重音在语句组织和语义表达中的作用等问题。  相似文献   
228.
Parallel lives: Community psychology in Latin America and the United States   总被引:3,自引:0,他引:3  
Comparing the history of community psychology as it developed in the U.S. during the 1960s with the community psychology that developed 10 years later in Latin America, one is reminded of the title of Plutarch’s masterpice,Parallel Lives. Although there was very little contact or communication between the first community psychologists in these regions, very similar principles and orientations evolved. These similarities are particularly striking given the many ways in which the U.S. and Latin American contexts and histories differ. Since most readers are expected to be familiar with the history of community psychology as it developed in the U.S., this paper focuses primarily on the development of community psychology in Latin America in order to highlight areas of convergence as well as divergence from the U.S. experience. This paper is based on an address presented at the Fourth Biennial Conference, Society for Community Research and Action, Division 27 of the American Psychological Association, William and Mary College, Williamsburg, Virginia, 1993. The author acknowledges the valuable help received from J. R. Newbrough and from the referees in the revision of this paper.  相似文献   
229.
A number of authors have proposed that psychopathic individuals possess an abnormally constricted time horizon (i.e., foreshortened sense of the future). This hypothesis was tested among 101 undergraduates, who were administered a battery of (1) self-report indices of psychopathic personality traits, antisocial behavior, and normal-range personality traits; (2) self-report indices of time perspective; (3) projective tests of time perspective; and (4) laboratory tasks assessing time estimation and capacity for foresight and impulse control. Measures of psychopathy/antisocial behavior tended to be negatively correlated with several self-report indices assessing preoccupation with the future and with a projective task assessing the frequency of thoughts concerning future events, although only one of the correlations with this latter task was significant. In most cases these correlations were not attributable to the variance shared by measures of psychopathy/antisocial behavior and measures of (low) anxiety-proneness, although several correlations decreased substantially after levels of harmavoidance were controlled. In contrast, measures of psychopathy/antisocial behavior were negligibly correlated with laboratory tasks. These results provide mixed support for the short time horizon hypothesis and suggest that further attention to the role of method factors in investigations of future time perspective is warranted.  相似文献   
230.
The item and scale factor structure of the Basic Personality Inventory (BPI) was examined in a sample of 486 offenders incarcerated for violent and sexual crimes. Separate principal-component analyses of the items for each of the 11 clinical scales, critical item scale, and social desirability scale indicated a one-dimensional factor solution for all scales except Depression and Persecutory Ideation. The Depression scale's two factors were Hopelessness and Depressive Affect and the Persecutory Ideation scale's two factors were General Paranoia and Perception of External Control. Although the factors for these two scales may assist in interpretation, the correlations between the factors and the total score of their respective scale were high. Confirmatory factor analysis of the 220 items from the 11 clinical scales supported the factorial logic of the scoring key. Analysis of the 11 clinical scales resulted in two factors: General Psychopathology/Adjustment and Antisocial Orientation. The results suggest that all but two scales can be viewed as unidimensional thereby allowing for a straightforward clinical interpretation. These analyses support the internal structure of the BPI and lend credence to external validity work with forensic populations.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号