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   17607篇
  免费   1474篇
  国内免费   1159篇
  2023年   217篇
  2022年   205篇
  2021年   299篇
  2020年   537篇
  2019年   624篇
  2018年   590篇
  2017年   702篇
  2016年   688篇
  2015年   450篇
  2014年   562篇
  2013年   1886篇
  2012年   389篇
  2011年   484篇
  2010年   426篇
  2009年   613篇
  2008年   801篇
  2007年   879篇
  2006年   822篇
  2005年   714篇
  2004年   606篇
  2003年   508篇
  2002年   459篇
  2001年   281篇
  2000年   266篇
  1999年   225篇
  1998年   179篇
  1997年   156篇
  1996年   123篇
  1995年   111篇
  1994年   102篇
  1993年   84篇
  1992年   63篇
  1991年   49篇
  1990年   49篇
  1989年   30篇
  1988年   40篇
  1987年   28篇
  1985年   390篇
  1984年   443篇
  1983年   355篇
  1982年   455篇
  1981年   447篇
  1980年   449篇
  1979年   396篇
  1978年   460篇
  1977年   367篇
  1976年   373篇
  1975年   286篇
  1974年   282篇
  1973年   244篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
Philip Hefzer 《Zygon》1993,28(1):77-101
Abstract. The paper consists of an argument that goes as follows. Symbols and their elaboration into myths constitute Homo sapiens 's most primitive reading of the world and the relation of humans to that world. They are, in other words, primordial units of cultural information, emerging very early in human history, representing a significant achievement in the evolution of human self-consciousness and reflection. The classic myths of Fall and Original Sin, as well as the doctrines to which they gave rise, are further interpretations of this primordial information. The doctrinal traditions of the first four centuries of Christianity are surveyed. Three sets of data as interpreted by the biological sciences are offered as resources for understanding the biogenetic grounds of the experience that the symbols, myths, and doctrines of Fall and Original Sin seek to interpret. The conclusions to be drawn are that (1) the symbolic material is indeed commensurate with the scientific understandings, and (2) the scientific interpretations deepen our understanding of the symbols, while (3) the conversation between the symbols and the science once again raises certain perennial questions about human existence.  相似文献   
242.
243.
244.
驾驶员心理品质检测中的杆型人形图法   总被引:1,自引:0,他引:1  
在汽车驾驶员心理品质检测研究中,我们根据数学中的多变量图分析方法,并汲取简笔画的优点,用19个人形图变量代表检测所得的17种心理品质数据,来具体、形象地再现每个驾驶员心理品质变量的整体关系。这对于检测结果的分类或进行系统化分析具有重要的实用意义。  相似文献   
245.
In contemporary American scholarship, interpretation of Aristotle'sRhetoric has become the locus of sustained and sharp controversy. Differing views of theRhetoric and its significance have become tokens in a more general dispute about what rhetoric is or ought to be. This essay examines three central issues that have emerged in this larger arena of controversy: the relationship between Aristotelian and Platonic conceptions of rhetoric, the relationships among rhetoric, ethics, and epistemology in Aristotle, and the placement of rhetoric within Aristotle's system of arts and sciences.  相似文献   
246.
The crane's foot: The rise of the pedigree in human genetics   总被引:1,自引:1,他引:0  
The standard pedigree used by geneticists is intimately connected to the history of genetics. Pedigrees drawn today are based on standards established in the early decades of the twentieth century. Those standards were established by geneticists who pursued an active interest in eugenics. The slightly different standards followed in America vs. England to some extent followed the stronger support of Mendelism by the Americans, as well as the individual preferences of the leading human geneticists in those countries.  相似文献   
247.
The substitutability of reinforcers   总被引:5,自引:3,他引:2       下载免费PDF全文
Substitutability is a construct borrowed from microeconomics that describes a continuum of possible interactions among the reinforcers in a given situation. Highly substitutable reinforcers, which occupy one end of the continuum, are readily traded for each other due to their functional similarity. Complementary reinforcers, at the other end of the continuum, tend to be consumed jointly in fairly rigid proportion, and therefore cannot be traded for one another except to achieve that proportion. At the center of the continuum are reinforcers that are independent with respect to each other; consumption of one has no influence on consumption of another. Psychological research and analyses in terms of substitutability employ standard operant conditioning paradigms in which humans and nonhumans choose between alternative reinforcers. The range of reinforcer interactions found in these studies is more readily accommodated and predicted when behavior-analytic models of choice consider issues of substitutability. New insights are gained into such areas as eating and drinking, electrical brain stimulation, temporal separation of choice alternatives, behavior therapy, drug use, and addictions. Moreover, the generalized matching law (Baum, 1974) gains greater explanatory power and comprehensiveness when measures of substitutability are included.  相似文献   
248.
Delay reduction: current status.   总被引:6,自引:6,他引:0       下载免费PDF全文
Delay-reduction theory states that the effectiveness of a stimulus as a conditioned reinforcer may be predicted most accurately by the reduction in time to primary reinforcement correlated with its onset. We review support for the theory and then discuss two new types of experiments that assess it. One compares models of choice in situations wherein the less preferred outcome is made more accessible; the other investigates whether frequency of conditioned reinforcement affects choice beyond the effect exerted by frequency of primary reinforcement.  相似文献   
249.
Violations of strong stochastic transitivity in concurrent-chains choice were first reported by Navarick and Fantino. In a series of articles, Navarick and Fantino concluded that neither a unidimensional model capable of predicting exact choice probabilities nor a fixed-variable equivalence rule was possible for the concurrent-chains procedure. I show that when choice is modeled contextually (i.e., when preference for a schedule is affected by factors other than the schedule itself, e.g., aspects of the alternative schedule), a unidimensional, exact-choice probability model is possible that both predicts the intransitivities reported by Navarick and Fantino and provides a fixed-variable equivalence rule for the concurrent-chains procedure. The contextual model is an extension of the generalized matching law and violates a key assumption underlying traditional choice models—simple scalability—because of (a) schedule interdependence and (b) bias from procedural contingencies. Therefore, strong stochastic transitivity cannot be expected to hold. Contextual scalability is analyzed to reveal a hierarchy of context effects in choice. Navarick and Fantino's intransitivities can be satisfactorily explained by bias. If attribute sensitivity is context dependent, however, and if there are similarity structures among choice alternatives, the contextual model is shown to be able to predict violations of ordinal preference. Therefore, it may be possible to formulate a deterministic, general psychophysical model of choice as a behavioral alternative to probabilistic, multidimensional choice theories.  相似文献   
250.
In this paper, we applied the behavioral-economic concept of unit price to the study of reinforcer magnitude in an attempt to provide a consistent account of the effects of reinforcer magnitude on behavior. Recent research in the experimental analysis of behavior and in behavioral pharmacology suggests that reinforcer magnitude interacts with the schedule of reinforcement to determine response rate and total consumption. The utility of the unit-price concept thus stems from its ability to quantify this interaction as a cost-benefit ratio (i.e., unit price = characteristics of the schedule of reinforcement divided by magnitude of reinforcement). Research employing the unit-price concept has shown that as unit price increases, a positively decelerating function exists for consumption (i.e., a function with an increasingly negative slope, when plotted on log coordinates) and a bitonic function exists for response rate. Based on these findings, the present analysis applied the unit-price concept to those studies of reinforcer magnitude and drug self-administration that examined the effects of reinforcer magnitude on response rate using simple schedules of reinforcement (e.g., fixed-ratio schedule). This resulted in three findings: (a) Reinforcer-magnitude manipulations and schedule manipulations interact in a manner that can be quantified in terms of unit price as benefit and cost factors, respectively; (b) different reinforcer-magnitude manipulations are functionally interchangeable as benefit factors in the unit-price ratio; and (c) these conclusions appear warranted despite the differences in reinforcers (food or drug), species (dogs, monkeys, or rats), and schedules (interval or ratio), and despite the fact that these studies were not designed for a unit-price analysis. In methodological terms, these results provide further evidence that employing the unit-price concept is a parsimonious method for examining the effects of reinforcer magnitude. In theoretical terms, these results suggest that a single process may underlie the effect of combined reinforcer-magnitude and schedule manipulations.  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