全文获取类型
收费全文 | 62180篇 |
免费 | 1035篇 |
国内免费 | 5篇 |
专业分类
63220篇 |
出版年
2020年 | 642篇 |
2019年 | 765篇 |
2018年 | 971篇 |
2017年 | 1071篇 |
2016年 | 1138篇 |
2015年 | 835篇 |
2014年 | 990篇 |
2013年 | 4558篇 |
2012年 | 1808篇 |
2011年 | 1834篇 |
2010年 | 1196篇 |
2009年 | 1163篇 |
2008年 | 1664篇 |
2007年 | 1614篇 |
2006年 | 1433篇 |
2005年 | 1328篇 |
2004年 | 1240篇 |
2003年 | 1205篇 |
2002年 | 1226篇 |
2001年 | 1749篇 |
2000年 | 1688篇 |
1999年 | 1272篇 |
1998年 | 612篇 |
1997年 | 602篇 |
1992年 | 1138篇 |
1991年 | 1059篇 |
1990年 | 1112篇 |
1989年 | 1011篇 |
1988年 | 1007篇 |
1987年 | 974篇 |
1986年 | 1014篇 |
1985年 | 996篇 |
1984年 | 890篇 |
1983年 | 827篇 |
1982年 | 608篇 |
1981年 | 637篇 |
1979年 | 965篇 |
1978年 | 690篇 |
1977年 | 618篇 |
1976年 | 581篇 |
1975年 | 827篇 |
1974年 | 918篇 |
1973年 | 949篇 |
1972年 | 767篇 |
1971年 | 756篇 |
1970年 | 705篇 |
1969年 | 756篇 |
1968年 | 904篇 |
1967年 | 842篇 |
1966年 | 761篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
Gerontologists have long been concerned with the impact of individual-difference factors on memory. This study used a large sample (N = 2,495) of adult volunteers aged 18 to 90 years to determine if a set of individual-difference variables--vocabulary, education, depression, gender, marital status, and employment status--mediates the effects of aging on a wide range of laboratory-analogue tests of everyday memory. The data indicated that age was consistently the most significant predictor of memory performance, followed by vocabulary and gender. Vocabulary totally mediated age effects on a prose memory measure, and partial mediation of aging effects--primarily by vocabulary and gender--was observed on 5 other memory tests. These data suggest that when health samples of volunteers serve as research subjects, these individual differences can affect some memory test scores, but age remains the best overall predictor of memory performance. 相似文献
152.
Short-term memory for actions was investigated for young adult and elderly adult subjects with the Brown-Peterson procedure at retention intervals of 0 and 15 s. The short-term memory trials were followed by the long-term recall of the prior to-be-remembered actions. The 15-s retention interval was filled either with no activity or with 1 of 3 different interfering activities. Verbal interference had little effect on short-term memory at either age level. Actions performed in the interval either by the subjects or by the experimenter produced significantly lower recall scores at each age level, with the decrement being more pronounced for the elderly than for the young subjects. The long-term memory results indicated that successful short-term recall enhanced later long-term recall, regardless of age level. 相似文献
153.
The dimensions by which adults of differing ages experience emotion were studied by self-administering questionnaires administered to older adults (n = 828) recruited from Elderhostel programs, middle-aged (ages 30-59) children of Elderhostel attenders (n = 231), and young adult (ages 18-29) subjects recruited from college classes or through Elderhostel participants (n = 207). Elders were higher in emotional control, mood stability, and emotional maturity through moderation and leveling of positive affect and lower in surgency, psychophysiological responsiveness, and sensation seeking. These findings are consistent with the hypothesized increase in self-regulatory capacity with age. These cross-sectional differences cannot, however, be distinguished from cohort-related explanations; they require considerable replication across different types of subjects and further characterization of the dimensions in terms of their functions for self-regulation. 相似文献
154.
155.
H. G. Coenen 《Argumentation》1992,6(3):321-336
Aristotle considers all examples, as far as they are used as rhetorical arguments, to be inductions (Rhetoric 1, 2, 8). On the other hand, he finds it worthwhile to distinguish different kinds of examples (viz., historical example, comparison, and fable). Moreover, comparisons and fables are said to be made by the orator, whereas historical examples are not (Rhetoric 2, 20, 2s). The present article attempts to explain this opposition.A close examination of what can be meant by induction reveals that this term applies differently to historical examples and to comparisons and fables. In a broader sense, all examples can be called inductions, insofar as a certain logical relation, different from the syllogistic one, obtains between conclusion and premises. This relation, however, is unable to explain why examples can serve as arguments. Applied to historical examples only, the term induction preserves its original meaning of checking samples in a number sufficient to yield generalization. In its narrow sense, induction gives a satisfactory account of how historical examples work. As for comparisons and fables — to which induction applies in a broader sense only — Aristotle fails to explain what makes them arguments. The explanation, missing in Rhetoric 2, 20, can, however, be given according to the general lines of Aristotelian dialectics and rhetorics. The main task of comparison and fable is to elaborate a so far unconsidered middle term (M) meeting the following conditions: the hearer is prepared to agree that M applies to the subject of the conclusion and that the predicate of the conclusion applies to M. All examples make use of a general proposition from which their conclusion can be inferred. Historical examples (like real inductions) produce instances, in order to confirm a proposition previously admitted as suitable premise, provided that its truth can be proved. Comparison and fables, by introducing a new middle term, try to form a premise susceptible of being admitted without proof.
La classification des exemples d'après Aristote (Rhétorique 2,20)相似文献
156.
157.
M H Huang S S Hull R D Foreman R Lazzara S Wolf 《Integrative Physiological and Behavioral Science》1992,27(1):6-12
The shortening of the QT interval of the electrocardiogram coincident with acceleration of heart rate and vice versa has been accepted for many years as evidence that the action potential duration and hence QT are necessarily dependent on heart rate. Exceptions to this rule have been attributed to the intervention of counteracting autonomic effects. In order to test this assumption, 26 conscious dogs divided into three groups were tested during baroreceptor stimulation by a bolus injection of phenylephrine. Seventeen dogs had been used in earlier studies in which they had undergone an experimental anterior myocardial infarction with apparent full recovery. A group of those dogs underwent beta-adrenergic blockade by intravenous atenolol 30 min prior to the baroreceptor activation. To test the intactness of the baroreceptor responses in the previously infarcted dogs, a third group of nine dogs that had had no prior myocardial infarction was included. All dogs were adapted to the laboratory environment and were not sedated during experiments. Simultaneous recordings of RR, QT interval, and phasic arterial pressure were made in all dogs before and during baroreceptor stimulation. In the normal group, and the previously infarcted group that received no atenolol, baroreceptor stimulation elicited a small (8/msec), but significant prolongation of the QT associated with a nearly 50% reduction in heart rate. The QT interval of the atenolol-treated dogs, although significantly more prolonged before stimulation, remained unchanged during the reflex. The data indicate that withdrawal of ventricular sympathetic tone may prolong the QT interval, thereby confirming the role of sympathetic innervation in the control of QT.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
158.
159.
This article presents a model of how attractiveness influences adjustment and reviews the relevant evidence. The model suggests that attractiveness influences adjustment through a three-stage process. Varying levels of physical attractiveness create differential responses in other people (Stage 1). These differential responses in others as a function of a person's appearance then result in differential treatment of the person (Stage 2), with such differential treatment eventually resulting in differential adjustment (Stage 3). These three stages are considered to occur in a reciprocal manner across the life span. Empirical support is found for each stage from early childhood to adulthood. Attractiveness accounts for 6% to 16% of the variance in measures of subjective adjustment as well as sociometric and behavioral measures of interpersonal adjustment. 相似文献
160.
Takeo Watanabe George L. Zimmerman Patrick Cavanagh 《Attention, perception & psychophysics》1992,52(2):161-166
We examined whether the orientation-contingent color aftereffect (the McCollough effect) could be mediated by subjective horizontal and vertical structure induced by the perception of transparency. In our experiments, red vertical bars and green horizontal bars were alternated as an adapting stimulus. After adaptation, subjects (n=6) were asked to adjust the green and red saturation of a test pattern until they obtained a neutral gray. Horizontal and vertical stripes were combined in the test pattern in three different ways: (1) overlapping with a luminance combination that gave rise to a perception of transparent overlays of horizontal and vertical stripes (valid transparency condition), (2) overlapping with luminance combinations that did not induce a perception of transparency (invalid transparency condition) and that appeased more as a patchwork of checks, and (3) presented in adjacent, nonoverlapping areas. Our results showed that the McCollough effect was significantly greater in the valid transparency condition than in the invalid transparency conditions. The effect in the valid transparency condition was nevertheless less strong than was the effect seen with the standard test stimulus made up of nonoverlapping vertical and horizontal stripes, Our results suggest that the McCollough effect can be mediated by the subjective spatial organization (inner representation of vertical and horizontal stripes) that accompanies the perception of transparency in our stimulus. 相似文献