全文获取类型
收费全文 | 7799篇 |
免费 | 395篇 |
国内免费 | 5篇 |
出版年
2024年 | 18篇 |
2023年 | 99篇 |
2022年 | 131篇 |
2021年 | 171篇 |
2020年 | 226篇 |
2019年 | 256篇 |
2018年 | 387篇 |
2017年 | 372篇 |
2016年 | 326篇 |
2015年 | 224篇 |
2014年 | 260篇 |
2013年 | 998篇 |
2012年 | 561篇 |
2011年 | 546篇 |
2010年 | 374篇 |
2009年 | 238篇 |
2008年 | 467篇 |
2007年 | 370篇 |
2006年 | 342篇 |
2005年 | 296篇 |
2004年 | 195篇 |
2003年 | 197篇 |
2002年 | 183篇 |
2001年 | 78篇 |
2000年 | 105篇 |
1999年 | 68篇 |
1998年 | 39篇 |
1997年 | 38篇 |
1996年 | 30篇 |
1995年 | 31篇 |
1994年 | 28篇 |
1993年 | 26篇 |
1992年 | 41篇 |
1991年 | 30篇 |
1990年 | 32篇 |
1989年 | 33篇 |
1988年 | 30篇 |
1987年 | 23篇 |
1986年 | 16篇 |
1985年 | 22篇 |
1984年 | 18篇 |
1983年 | 19篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1976年 | 15篇 |
1974年 | 14篇 |
1972年 | 15篇 |
1965年 | 13篇 |
排序方式: 共有8199条查询结果,搜索用时 15 毫秒
201.
This work is divided in two papers (Part I and Part II). In Part I, we study a class of polymodal logics (herein called the class of "Rare-logics") for which the set of terms indexing the modal operators are hierarchized in two levels: the set of Boolean terms and the set of terms built upon the set of Boolean terms. By investigating different algebraic properties satisfied by the models of the Rare-logics, reductions for decidability are established by faithfully translating the Rare-logics into more standard modal logics. The main idea of the translation consists in eliminating the Boolean terms by taking advantage of the components construction and in using various properties of the classes of semilattices involved in the semantics. The novelty of our approach allows us to prove new decidability results (presented in Part II), in particular for information logics derived from rough set theory and we open new perspectives to define proof systems for such logics (presented also in Part II). 相似文献
202.
Data illustrating the biological week and chronomes are presented in recognition of extensive work of G. Hildebrandt. 相似文献
203.
Bernhard Plé 《Journal of Happiness Studies》2000,1(4):423-445
Auguste Comte (1798–1857) is the founder of a French school of thought that became famous for its encyclopaedic account of the sciences as well as for its exposition of what was designed as a way out of a state of intellectual and moral crisis. This essay demonstrates that there is a linkage between the diagnosis of crisis and the pursuit of happiness in Comte's foundation of positivism. It begins by distinguishing Comte's notion of positivism from that of a value-free science. In analysing Comte's peculiar usage of the term happiness, the essay shows that happiness is understood as the result of the convergence (consensus) of three components: a scientific conception of the world, the feelings of love and veneration, and a wisely ordered activity. The essay then demonstrates that the first of these components is of primary importance inasmuch as it is to frame a new horizon within which man is expected to return to a healthy state of mind, to reshape both his hopes and activities, and to discover his own participation in a supreme order acting through the laws of nature as well as through those of the civilization in which he lives. Conveying this new horizon to citizens of a lasting Republic is the sacred mission of sociology. The essay concludes by pointing out that Comte's conception of happiness can be assessed as unifying some main qualities of life as they are classified in Ruut Veenhoven's fourfold matrix. 相似文献
204.
Pollatsek A Hyönä J Bertram R 《Journal of experimental psychology. Human perception and performance》2000,26(2):820-833
The processing of transparent Finnish compound words was investigated in 2 experiments in which eye movements were recorded while sentences were read silently. The frequency of the second constituent had a large influence (95 ms) on gaze duration on the target words, but its influence was relatively late in processing: A clear effect only occurred on the probability of a third fixation. The frequency of the whole compound word had a similar influence on gaze duration (82 ms) and influenced eye movements at least as rapidly as did the frequency of the second constituent. These results, together with an earlier finding that the frequency of the first constituent affected the first fixation duration, indicate that the identification of these compound words involves parallel processing of both morphological constituents and whole-word representations. 相似文献
205.
The aim of this research is to model and simulate the loss of visual resolution as a function of retinal eccentricity in the perception of natural scenes. The model of visual resolution is based on a space-variant low-pass filter, having a variable convolution kernel according to retinal eccentricity. The parameters of the model are computed from psychophysical measures of visual acuity as a function of retinal eccentricity. The implementation of the model allowed us to generate images of scenes with nonhomogeneous space-variant resolution, simulating the filtering executed by the eye. These scenes are used to test and optimise the model by means of experiments in static vision (through tachistoscopic presentations) and in dynamic vision where the resolution of the scene is computed, in real-time, as a function of the location of gaze. 相似文献
206.
Pollok B Prior H Güntürkün O 《Journal of comparative psychology (Washington, D.C. : 1983)》2000,114(2):148-157
The development of object permanence was investigated in black-billed magpies (Pica pica), a food-storing passerine bird. The authors tested the hypothesis that food-storing development should be correlated with object-permanence development and that specific stages of object permanence should be achieved before magpies become independent. As predicted, Piagetian Stages 4 and 5 were reached before independence was achieved, and the ability to represent a fully hidden object (Piagetian Stage 4) emerged by the age when magpies begin to retrieve food. Contrary to psittacine birds and humans, but as in dogs and cats, no "A-not-B error" occurred. Although magpies also mastered 5 of 6 invisible displacement tasks, evidence of Piagetian Stage 6 competence was ambiguous. 相似文献
207.
Brédart S 《Memory (Hove, England)》2000,8(2):123-128
The aim of the present study was to evaluate two explanations for the non-occurrence of false memories in the Deese-Roediger-McDermott (DRM) paradigm. One explanation was that a critical lure is not recalled because the list failed to evoke it in the participant's mind. Another possible explanation was that the participant would identify the critical lure and would remember, at the time of recall, that the lure was not produced by an external source. In order to explore these two possible explanations for the non-occurrence of false memories, an experimental phase was added to the usual DRM paradigm: participants were asked to recall items they thought of but did not recall because these items were not members of the list presented by the experimenter. Among participants who did not recall the critical lure during the standard recall task, those who recalled the critical lure during the additional phase outnumbered those who did not recall it. This result is more consistent with the second explanation than with the first one. 相似文献
208.
Zeelenberg R 《Acta psychologica》2005,119(1):107-121
In a recent article, P.A. Higham (2002) [Strong cues are not necessarily weak: Thomson and Tulving (1970) and the encoding specificity principle revisited. Memory &Cognition, 30, 67-80] proposed a new way to analyze cued recall performance in terms of three separable aspects of memory (retrieval, monitoring, and report bias) by comparing performance under both free-report and forced-report instructions. He used this method to derive estimates of these aspects of memory in an encoding specificity experiment similar to that reported by D.M. Thomson and E. Tulving (1970) [Associative encoding and retrieval: weak and strong cues. Journal of Experimental Psychology, 86, 255-262]. Under forced-report instructions, the encoding specificity manipulation did not affect performance. Higham concluded that the manipulation affected monitoring and report bias, but not retrieval. I argue that this interpretation of the results is problematic because the Thomson and Tulving paradigm is confounded, and show in three experiments using a more appropriate design that encoding specificity manipulations do affect performance in forced-report cued recall. Because in Higham's framework forced-report performance provides a measure of retrieval that is uncontaminated by monitoring and report bias it is concluded that encoding specificity manipulations do affect retrieval from memory. 相似文献
209.
The purpose of this study was to identify factors associated with early onset of sexual intercourse. Within an ecological system's conceptual framework, familial factors associated with early onset of sexual activity were identified in a sample of 425 adolescents from San Juan metro area schools. Measures included questions about sexual activity, sexual permissiveness, and such familial variables as: discipline, parental supervision, and parental support. Significant relationships were observed between early onset of sexual intercourse and parental supervision, discipline, parental support, and parents' marital status. Results suggest the key role of parents and family in prevention of HIV-risk behaviors among adolescents in terms of delaying sexual onset. Overall, the study described youths who postponed sexual activity as having greater support, supervision, and parental involvement. 相似文献
210.