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   8400篇
  免费   320篇
  国内免费   1篇
  2020年   103篇
  2019年   141篇
  2018年   157篇
  2017年   193篇
  2016年   216篇
  2015年   158篇
  2014年   203篇
  2013年   914篇
  2012年   326篇
  2011年   318篇
  2010年   234篇
  2009年   214篇
  2008年   311篇
  2007年   294篇
  2006年   280篇
  2005年   253篇
  2004年   264篇
  2003年   243篇
  2002年   293篇
  2001年   105篇
  2000年   102篇
  1999年   128篇
  1998年   138篇
  1997年   124篇
  1996年   111篇
  1995年   132篇
  1994年   109篇
  1993年   102篇
  1992年   107篇
  1991年   100篇
  1990年   90篇
  1989年   82篇
  1988年   66篇
  1987年   66篇
  1986年   69篇
  1985年   85篇
  1984年   106篇
  1983年   119篇
  1982年   115篇
  1981年   144篇
  1980年   104篇
  1979年   121篇
  1978年   125篇
  1977年   117篇
  1976年   102篇
  1975年   103篇
  1974年   105篇
  1973年   66篇
  1972年   63篇
  1969年   55篇
排序方式: 共有8721条查询结果,搜索用时 31 毫秒
71.
James Blachowicz 《Synthese》1987,71(3):235-321
In recent years, there have been some attempts to defend the legitimacy of a non-inductive generative logic of discovery whose strategy is to analyze a variety of constraints on the actual generation of explanatory hypotheses. These proposed new theories, however, are only weakly generative (relying on sophisticated processes of elimination) rather than strongly generative (embodying processes of correction).This paper develops a strongly generative theory which holds that we can come to know something new only as a variant of what we already know — and that the novelty of this variant is not thereby eliminated nor beyond our powers of characterization, a double requirement that is vital for resolving the Meno paradox. In this light, the discovery of a new hypothesis is taken as the correction of an antecedent hypothesis in response to the discrepancies between the predictions generated by that antecedent hypothesis and the desired result (e.g. the actual data to be explained). This process comprises two parallel operations: the first, which demonstrates the positive role of the facts in generating new explanations, involves a mapping between multiple hypotheses and sets of predictions generated from those hypotheses, for the purpose of taking the actual data as a determinable variant of neighboring sets of predictions. This mapping permits the facts to indicate how corrective adjustments in the working hypothesis should be made; the second operation, which demonstrates the positive role of explanations in generating new facts, involves a mapping between differently construed versions of the actual data and the conceptualizations derived from those perceptual versions, for the purpose of taking the working hypothesis as a determinable variant of these neighboring conceptualizations. This mapping permits a given hypothesis to generate predictions increasingly closer to the actual facts.The proposed theory provides the basis for a reformed conception of justification. Because hypotheses are meaningful only as variants of neighboring hypotheses, and because such variation is corrective, their justification in the reformed sense will incorporate not only their justification in the traditional sense, but their generation as well.  相似文献   
72.
This paper reports the results of a study designed to separate the voicing redundancy from nasality in American English and to determine their individual saliencies. Sixty-seven subjects judged the similarity of nonnasal pairs versus nasal pairs of CV and VC nonsense syllables on a 5-point magnitude-estimation task. The 80 stimuli were constructed to control and to demand subjects' cognitive strategies for coping with redundancy rather than experimental manipulation of the data. They were developed from the consonantal repertoire of / b d g m n p t k / paired with the vowels / i a u /, totaling 72 pairs of dyads. Eight additional stimuli of similar structure, testing multifeature and identity contrasts, were included to monitor the validity of the experimental procedure. Results indicated that (a) speech redundancy can be circumvented cognitively, (b) nasality was more salient (different) than voicing, and (c) a recency effect was found. These findings are discussed in reference to existing data.  相似文献   
73.
The relationship between risk factors and the severity and type of childhood disorder, as measured by parent-completed Child Behavior Checklists, was examined for 768 children, ages 4–16, seen at a child mental health center. Regression analyses revealed no significant relationships between any combination of risk factors and the total number of behavior problems, internalizing, or externalizing scores for the entire group, males and females separately, or for the age and sex groupings of 6- to 11- and 12-to 16-yearolds. Chi-square tests revealed no relationship of profile type with any risk factor or with total number of risk factors. Implications for broad-based child assessment and risk factor research within a clinical population are discussed.We wish to thank Orin Bolstad, Linda Magnuson, and Julian Taplin for their assistance in this project.  相似文献   
74.
75.
Seventy-five patients admitted to the psychiatric unit of a general hospital were administered a brief neuropsychological screening battery. Discharge diagnoses obtained from the medical records revealed that 20% had brainbased pathology. A discriminant function analysis resulted in a five-variable model (Symbol-Digit Modalities Test, educational level, Psychiatric-Organic subscale of the MMPI, and Shipley Vocabulary and Abstraction scores) which correctly classified 84% of the subjects, with 87% correct identification of the brain-damaged group. A jackknife cross-validation procedure resulted in comparable hit rates.  相似文献   
76.
77.
Adherents to the traditional model of alcoholism explain alcoholic behavior as a consequence of alcoholism. Alcoholism is identified as an unseen, unmeasured entity inherent in alcoholics. This concept parallels the thinking of Copernicus, Kepler, Galileo, and Newton, who believed in an unseen, unmeasurable creator behind the physical world. These traditional approaches contrast with the emergent model of alcoholism and twentieth-century scientific thought. Emergent scientific model adherents explain alcoholic behavior without resort to unseen factors. Since the traditional and emergent scientific models begin with different assumptions, model adherents experience communication difficulties. Future developments with determine which model will dominate the field of alcohol studies and treatment.  相似文献   
78.
School psychologists serving a national, systematic sample of public elementary and secondary schools were surveyed regarding recent referrals. Most referrals were initiated by school staff members (75% of referrals), and the majority occured initially through formal mechanisms (55% of referrals). Most informal requests for assistance or information eventually became, or were thought likely to become, formal referrals. In 92% of cases, the referral agent's initial communication with the psychologist included some designation of what the pupil was doing or not doing that was viewed as problematic. Poor academic performance was of primary concern in 52% of referrals and social/emotional problems in 31%. More boys were referred than girls, and one-half of referrals from the elementary grades involved pupils in grades K-2. Frequency of referral and reason for referral were not independent of pupil's grade or sex. Reason for referral was independent of time of year (October vs. May) and geographical region.  相似文献   
79.
This paper provides a comprehensive formulation of Erik Erikson's theory of ego identity formation as it pertains to both the identity stage and to the remainder of the life cycle. The structure of the identity stage is discussed in terms of its more universal features and in terms of features more specific to North American society. The role played by “institutionalized moratoria” in influencing the outcome of the identity crisis and subsequent development is discussed in the context of two Eriksonian notions ignored in the literature: the value orientation stages and the struggle between the ego and superego for dominance of the personality. As part of the discussion, several constructive criticisms of Erikson's work are offered with the intent of making the theoretical formulation presented in this paper an appropriate basis for subsequent empirical investigations of his theory. One of the important implications of this paper is that it suggests that questions should be raised regarding the validity of the dominant research strategy currently in use.  相似文献   
80.
Normative data are presented for the probability of successfully completing 192 single-solution word fragments. Normative data on the familiarity of college students with the solution words are also given, along with estimates of word frequency from existing norms. Regression analyses were performed in order to predict fragment completion difficulty from familiarity, frequency, and several structural characteristics of the fragments. Familiarity, whether or not first and/or last letters appeared in the fragment, and the ratio of letters to missing letters in the fragment were included in the regression equation as significant predictors of difficulty for this fragment set.  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