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   169691篇
  免费   7719篇
  国内免费   164篇
  2021年   1510篇
  2020年   2814篇
  2019年   3477篇
  2018年   3503篇
  2017年   3966篇
  2016年   4632篇
  2015年   3937篇
  2014年   4833篇
  2013年   23537篇
  2012年   4472篇
  2011年   3515篇
  2010年   3815篇
  2009年   4757篇
  2008年   3679篇
  2007年   3265篇
  2006年   3897篇
  2005年   3880篇
  2004年   3407篇
  2003年   3025篇
  2002年   2819篇
  2001年   3149篇
  2000年   2985篇
  1999年   3040篇
  1998年   2811篇
  1997年   2660篇
  1996年   2569篇
  1995年   2404篇
  1994年   2384篇
  1993年   2332篇
  1992年   2503篇
  1991年   2383篇
  1990年   2205篇
  1989年   2135篇
  1988年   2135篇
  1987年   2149篇
  1986年   2123篇
  1985年   2332篇
  1984年   2469篇
  1983年   2248篇
  1982年   2357篇
  1981年   2321篇
  1980年   2158篇
  1979年   2154篇
  1978年   2138篇
  1977年   2119篇
  1976年   1909篇
  1975年   1928篇
  1974年   2008篇
  1973年   1874篇
  1972年   1466篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
Deborah G. Mayo 《Synthese》1992,90(2):233-262
I document some of the main evidence showing that E. S. Pearson rejected the key features of the behavioral-decision philosophy that became associated with the Neyman-Pearson Theory of statistics (NPT). I argue that NPT principles arose not out of behavioral aims, where the concern is solely with behaving correctly sufficiently often in some long run, but out of the epistemological aim of learning about causes of experimental results (e.g., distinguishing genuine from spurious effects). The view Pearson did hold gives a deeper understanding of NPT tests than their typical formulation as accept-reject routines, against which criticisms of NPT are really directed. The Pearsonian view that emerges suggests how NPT tests may avoid these criticisms while still retaining what is central to these methods: the control of error probabilities.A portion of this research was carried out during tenure of a National Endowment for the Humanities Summer Stipend Fellowship; I gratefully acknowledge that support. A version of this paper was presented at the 1987 meeting of the Society for Exact Philosophy. This paper benefited from discussions and communications with George Barnard and Isaac Levi. I thank Harlan Miller for helpful comments on earlier drafts.  相似文献   
993.
Binary programming models are presented to generate parallel tests from an itembank. The parallel tests are created to match item for item an existing seed test and match user supplied taxonomic specifications. The taxonomic specifications may be either obtained from the seed test or from some other user requirement. An algorithm is presented along with computational results to indicate the overall efficiency of the process. Empirical findings based on an itembank for the Arithmetic Reasoning section of the Armed Services Vocational Aptitude Battery are given.The Office of Naval Research, Program in Cognitive Science, N00014-87-C-0696 partially supported the work of Douglas H. Jones. The Rutgers Research Resource Committee of the Graduate School of Management partially supported the work of Douglas H. Jones and Ing-Long Wu. A Thomas and Betts research fellowship partially supported the work of Ing-Long Wu. The Human Resources Laboratory, United States Air Force, partially supported the work of Ronald Armstrong. The authors benefited from conversations with Dr. Wayne Shore, Operational Technologies, San Antonio, Texas. The order of authors' names is alphabetical and denotes equal authorship.  相似文献   
994.
Based on previous findings (B?sel et al., 1990) it was assumed that in concept learning tasks generating on hypotheses on a concept which has to be developed is accompanied by increases of the Alpha 1 power (7.5-10 Hz) in the spontaneous EEG activity. In this study 16 subjects performed five problem solving tasks with similar processing requirements. EEG data were analyzed by means of post hoc comparisons of subjects differing in performance quality. Additionally, four control tasks were employed in which, based on previous studies, variations in the Theta frequency range were expected. An effect in the Alpha 1 frequency band was observed in tasks requiring reconstructive recall or testing the usefulness of an mathematical algorithm. The creation of a rank order or mental map is accompanied by power increases in the lower portions of the Alpha 1 frequency band (7.5-8.5 Hz). Moreover a high amount of controlled variance (eta2 up to 34%) was obtained for this effect. Increases in EEG Theta power, which presumably indicate subjects' component analysis, were found before the subjects recognized parts of geometric figures or before relevant features in the "buddhist monk problem" were discriminated. The dynamics of EEG power over time is in examples of frequency/time plots in a figure, illustrated.  相似文献   
995.
This study explored the relationship between individual strategies of coping and blood pressure responses during and after mental stress. Blood pressure behavior was measured noninvasively and continuously before, during and after a mental stress situation in 27 normotensive subjects. Coping strategies were assessed with the Stressverarbeitungsfragebogen (SVF; coping with stress inventory). Two extreme groups were formed on the basis of the scores in the SVF. Results were: (a) Individuals who used coping strategies characterized by controlling the situation directly and constructively, in contrast to probands not using these strategies, exhibited lower blood pressure during the stress situation and a faster return to baseline levels after cessation of stress. (b) Subjects using a coping behavior characterized by the use of defense mechanisms such as suppression and denial, also showed lower blood pressure during stress but a significantly delayed return to baseline levels of blood pressure after stress was concluded.  相似文献   
996.
30 subjects participated in a discrimination experiment learning face-letter associations under four rotation conditions (45 degrees, 90 degrees, 135 degrees, 180 degrees). Under each condition two thirds of the faces were presented twice, upright and rotated away from the vertical; the remaining faces were presented once, upright or rotated. Learning is described by a joint Markov model: For faces that are presented twice it assumes a separate association and encoding process (two-stage-model), for faces that are presented once it assumes an association process (all-or-none-model). The Markov model fits the data for all four rotation conditions. The angle of rotation does not affect learning for faces that are presented once. For faces that are presented twice it influences both the association and the encoding process. For the angles employed, the effect of rotation can be approximated linearly. The results suggest that the encoding of a rotated face differs increasingly from an upright face as a function of these angles of rotation. This confirms analogous conclusions from mental rotation experiments.  相似文献   
997.
The purpose of the two experiments reported here was to observe the effects of degree of learning, interpolated tests, and retention interval, primarily on the rate of forgetting of a list of words, and secondarily on hypermnesia for those words. In the first experiment, all the subjects had one study trial on a list of 20 common words, followed by two tests of recall. Half of the subjects had further study and test trials until they had learned the words to a criterion of three correct consecutive recalls. Two days later, half of the subjects under each learning condition returned for four retention tests, and 16 days later, all the subjects returned for four tests. Experiment 2 was similar, except that all the subjects had at least three study trials followed by four recall tests on Day 1, intermediate tests were given 2 or 7 days later, and they all had final tests 14 days later. The results showed that rate of forgetting was attenuated by an additional intermediate set of tests but not by criterion learning. Hypermnesia was generally found over the tests that were given after a retention interval of 2 or more days. The best predictor of the amount of hypermnesia over a set of tests was the difference between overall cumulative recall and net recall on the first test of the set.  相似文献   
998.
In the present study, we examined letter detection in very frequent function-word sequences. It has been claimed that such sequences are processed in a unitized manner, thus preempting access to their constituent letters. In contrast, we showed that letter detection in the words for and the (1) was no more difficult when the words appeared in adjacent locations in a sentence (familiar) than when they appeared apart (less familiar sequence) and (2) was contingent upon the words' syntactic roles within the phrase. Thus, letter detection in for was easier when the sequence was separated by a clause boundary than when the words were part of the same clause. The advantage derived from clause separation was strongest when a comma divided clauses. These results challenge the unitization account of the "missing-letter" effect in common phrases and support a position where this phenomenon is seen to reflect the extraction of phrase structure during reading.  相似文献   
999.
This article presents cross-cultural evidence in support of the notion that adults' natural kind concepts are theory based but may be informed by knowledge/belief systems other than the biological. Three groups of subjects from western Nigeria--rural, urban, and elite--participated in the study. Subjects heard stories describing alterations of appearance; that is, one natural kind was made to resemble another in both ritual and nonritual contexts. Subjects then were required to judge the identity of the altered item and to give an explanation for the category judgment. It was predicted that subjects would make more nonpreservation-of-identity category judgments supported by supernatural explanations in the ritual contexts and that subjects' use of supernatural explanations would reflect the extent of their engagement with the supernatural. The first prediction was borne out; the second prediction was only partially supported. Discussion of the results emphasizes the importance of exploring the role of sociocultural factors in conceptual structure.  相似文献   
1000.
Some words have fewer direct associates than others, and, when words varying in set size are studied in a list-learning task, those with smaller sets are more likely to be recalled. This set-size effect is found in cued recall when the words are studied in the absence of related words, but not when studied in the presence of related words. Related words provide context and theoretically inhibit irrelevant associates. The present research determined that set-size effects are found when words are encoded in sentence contexts. In contrast to list-learning experiments, the results of three experiments found such effects even when lexically related words were present in the sentences. Other findings indicated that target-set-size effects were determined by the proximity of related words in the sentence and the nature of the test cue. The results are discussed in relation to a model for explaining set-size effects and to selective findings from the sentence-comprehension literature.  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