全文获取类型
收费全文 | 35808篇 |
免费 | 1311篇 |
国内免费 | 19篇 |
出版年
2020年 | 439篇 |
2019年 | 489篇 |
2018年 | 694篇 |
2017年 | 696篇 |
2016年 | 769篇 |
2015年 | 490篇 |
2014年 | 645篇 |
2013年 | 3086篇 |
2012年 | 1204篇 |
2011年 | 1251篇 |
2010年 | 845篇 |
2009年 | 833篇 |
2008年 | 1180篇 |
2007年 | 1144篇 |
2006年 | 1041篇 |
2005年 | 918篇 |
2004年 | 942篇 |
2003年 | 854篇 |
2002年 | 891篇 |
2001年 | 945篇 |
2000年 | 971篇 |
1999年 | 755篇 |
1998年 | 471篇 |
1997年 | 386篇 |
1994年 | 354篇 |
1993年 | 342篇 |
1992年 | 594篇 |
1991年 | 560篇 |
1990年 | 571篇 |
1989年 | 546篇 |
1988年 | 530篇 |
1987年 | 528篇 |
1986年 | 508篇 |
1985年 | 539篇 |
1984年 | 463篇 |
1983年 | 409篇 |
1982年 | 372篇 |
1981年 | 350篇 |
1979年 | 509篇 |
1978年 | 401篇 |
1977年 | 359篇 |
1975年 | 428篇 |
1974年 | 462篇 |
1973年 | 429篇 |
1972年 | 382篇 |
1971年 | 340篇 |
1969年 | 357篇 |
1968年 | 394篇 |
1967年 | 353篇 |
1966年 | 344篇 |
排序方式: 共有10000条查询结果,搜索用时 765 毫秒
921.
Michael J 《The Behavior analyst / MABA》1993,16(2):191-206
The first two books on behavior analysis (Skinner, 1938; Keller & Schoenfeld, 1950) had chapter-length coverage of motivation. The next generation of texts also had chapters on the topic, but by the late 1960s it was no longer being given much treatment in the behavior-analytic literature. The present failure to deal with the topic leaves a gap in our understanding of operant functional relations. A partial solution is to reintroduce the concept of the establishing operation, defined as an environmental event, operation, or stimulus condition that affects an organism by momentarily altering (a) the reinforcing effectiveness of other events and (b) the frequency of occurrence of that part of the organism's repertoire relevant to those events as consequences. Discriminative and motivative variables can be distinguished as follows: The former are related to the differential availability of an effective form of reinforcement given a particular type of behavior; the latter are related to the differential reinforcing effectiveness of environmental events. An important distinction can also be made between unconditioned establishing operations (UEOs), such as food deprivation and painful stimulation, and conditioned establishing operations (CEOs) that depend on the learning history of the organism. One type of CEO is a stimulus that has simply been paired with a UEO and as a result may take on some of the motivative properties of that UEO. The warning stimulus in avoidance procedures is another important type of CEO referred to as reflexive because it establishes its own termination as a form of reinforcement and evokes the behavior that has accomplished such termination. Another CEO is closely related to the concept of conditional conditioned reinforcement and is referred to as a transitive CEO, because it establishes some other stimulus as a form of effective reinforcement and evokes the behavior that has produced that other stimulus. The multiple control of human behavior is very common, and is often quite complex. An understanding of unlearned and learned establishing operations can contribute to our ability to identify and control the various components of such multiple determination. 相似文献
922.
923.
924.
Juan S. Gómez-Jeria Lic. Q. 《Journal of Near-Death Studies》1993,11(4):219-222
This paper describes a possible near-death experience (NDE) among the Mapuche people of Chile. The individual reporting the experience was in a cataleptic-like state for two days, the experience itself occurring at the end of this period. Some common features of NDEs, such as encounters with deceased people and being sent back, are present, together with clear evidence that past and present cultural environment shape in part the content of mental experiences.This work was funded in part by the University of Chile (DTI Project Q-3064).The author thanks Editorial Andrés Bello for permissionto translate the near death account into English. 相似文献
925.
G. A. Nesvetailov’s 《Knowledge, Technology, and Policy》1993,6(1):38-51
In this paper a method is outlined for measuring the diversity of the results of applied R&D with the use of IPC (International
Patent Classification). The method has been tested in the contexts of the academic physical, engineering, and chemical institutes.
The trend of applied research at a given institute increases both at the level of classes and subclasses, and at the IPC level.
Inventions developed within specializations at each institute have a greater efficiency than other forms of inventive activity.
The objective was to seek the optimal extent of diversification of applied R&D, which would simultaneously ensure the preservation
of the scientific specialization of an institute, the high level of scientific research associated with developing innovations,
and the high overall efficiency of each institute. 相似文献
926.
927.
Michael Leff 《Argumentation》1993,7(3):313-327
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
928.
929.
The purpose of this paper is twofold. First, it provides an historical overview of studies of risk, risk perception, and decision making under risk within the genetic counseling domain. Second, it proposes an alternative conceptualization and operationalization for the study of risk perception. The conceptualization involves probability, adversity, incompleteness, and ambiguity. Prior studies of risk perception focus on the recurrence risk and operationalize risk perception by asking for interpretations of the magnitude of the probability of the outcome. Their focus is on the probability of a particular outcome. We formulate the problem in terms of a gamble and suggest that risk perception be operationalized in terms of the riskiness of the gamble. Our focus is on the riskiness of a decision option which entails two or more outcomes. 相似文献
930.