全文获取类型
收费全文 | 25773篇 |
免费 | 858篇 |
国内免费 | 12篇 |
专业分类
26643篇 |
出版年
2019年 | 246篇 |
2018年 | 298篇 |
2017年 | 342篇 |
2016年 | 383篇 |
2015年 | 299篇 |
2014年 | 327篇 |
2013年 | 1835篇 |
2012年 | 631篇 |
2011年 | 644篇 |
2010年 | 408篇 |
2009年 | 422篇 |
2008年 | 601篇 |
2007年 | 544篇 |
2006年 | 483篇 |
2005年 | 477篇 |
2004年 | 444篇 |
2003年 | 449篇 |
2002年 | 467篇 |
2001年 | 686篇 |
2000年 | 676篇 |
1999年 | 470篇 |
1998年 | 244篇 |
1992年 | 467篇 |
1991年 | 452篇 |
1990年 | 457篇 |
1989年 | 458篇 |
1988年 | 408篇 |
1987年 | 420篇 |
1986年 | 446篇 |
1985年 | 482篇 |
1984年 | 410篇 |
1983年 | 376篇 |
1982年 | 271篇 |
1981年 | 314篇 |
1980年 | 243篇 |
1979年 | 439篇 |
1978年 | 317篇 |
1977年 | 287篇 |
1976年 | 274篇 |
1975年 | 412篇 |
1974年 | 460篇 |
1973年 | 485篇 |
1972年 | 411篇 |
1971年 | 404篇 |
1970年 | 379篇 |
1969年 | 405篇 |
1968年 | 493篇 |
1967年 | 477篇 |
1966年 | 454篇 |
1958年 | 252篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
851.
The partial credit model is considered under the assumption of a certain linear decomposition of the item × category parameters
ih into basic parameters
j. This model is referred to as the linear partial credit model. A conditional maximum likelihood algorithm for estimation of the
j is presented, based on (a) recurrences for the combinatorial functions involved, and (b) using a quasi-Newton approach, the so-called Broyden-Fletcher-Goldfarb-Shanno (BFGS) method; (a) guarantees numerically stable results, (b) avoids the direct computation of the Hesse matrix, yet produces a sequence of certain positive definite matricesB
k
,k=1, 2, ..., converging to the asymptotic variance-covariance matrix of the
. The practicality of these numerical methods is demonstrated both by means of simulations and of an empirical application to the measurement of treatment effects in patients with psychosomatic disorders.The authors thank one anonymous reviewer for his constructive comments. Moreover, they thankfully acknowledge financial support by the Österreichische Nationalbank (Austrian National Bank) under Grant No. 3720. 相似文献
852.
Four homing pigeons were trained over 5 months in a zero-delay, “arbitrary” matching-to-sample procedure with sample and comparison stimuli presented on any of three response keys. Birds were also required to complete a fixed-ratio 10 requirement on both sample and comparison stimuli to terminate their presentation. The procedure resulted in the establishment of relations that were not specifically trained and that can be characterized by the property of transitivity in a stimulus equivalence context. This result was in contrast with the findings obtained from most previous research with nonhuman subjects. 相似文献
853.
Seven undergraduates participated in a concurrent-choice experiment with monetary reinforcers. Response-independent analogues of variable-interval and variable-ratio schedules were used to assess whether subjects would maximize reinforcement rate. The optimal pattern of behavior, in terms of maximizing reinforcement rate, involved a large bias toward the ratio alternative, with only occasional sampling of the interval schedule. Most experiments with pigeons, however, demonstrate matching of response rates to reinforcement rates, with only slight biases for the ratio schedule. Although subjects in the present experiment allocated more time to the ratio alternative than required by matching, the magnitude of the bias did not approximate that predicted by a maximizing account. After exposure to clock stimuli correlated with the operation of each schedule, 1 subject's behavior did show a substantial level of bias, increasing the total number of reinforcers obtained, and lay at a point between the predictions of matching and maximizing. The other subjects, however, continued to respond less optimally. The present results can be accounted for by a view of matching that incorporates the effects of delayed reinforcement. 相似文献
854.
Using data collected from 1,987 employees at several locations of a large firm, this study investigates relationships between these employees' cognitive and attitudinal perceptions of an employee assistance program (EAP) and their propensity to use it. Familiarity with the program, perceived accessibility of it, and perceived managerial support for it are hypothesized to affect both employees' confidence in the program and their propensity to use it, and confidence in the EAP is further hypothesized to affect propensity to use. LISREL analysis supported the overall model, but the direct paths from the cognitive variables to propensity to use were not supported and confidence in the program was therefore indicated to be an essential mediating variable. Propensity to use an EAP is argued to be an important indicator of effective EAP implementation and suggestions are offered to management for promoting employee confidence in an EAP and ultimately their propensity to use it. 相似文献
855.
Four empirical studies of the roles of self-report questionnaires, tests, and ratings in employment interviews, staff appraisal,
and personnel validation surveys are presented in order to examine the number and relationships of psychological constructs
derived from data provided by candidates, employees, and their assessors. Test results are related to different kinds of criteria,
including job offers following interview, supervisor ratings on the job, and objective indices of work performance. From the
practices reported and observed in these various contexts, a theory of personal appraisal mechanisms in occupational settings
is derived using data reduction and linear regression methods. Applications of cognitive information processing theory to
self-reports and ratings by individuals, and of exchange theory to the social context of panel discussions among assessors,
provide a key to understanding why psychometric measures of personal qualities vary in their power to predict work performance
in spite of consistent construct validity. 相似文献
856.
Previous research indicates that vasopressin-containing (LE) rats are capable of adapting to the stress of food restriction,
whereas vasopressin-deficient (DI) rats cannot adapt to this stressor. It has been postulated that abnormalities in glucose
metabolism may be one of the factors leading to the demise of food-restricted DI rats. The present study was conducted to
determine if taste preferences are altered in DI animals and if the presentation of exogenous glucose, in the form of sucrose
solutions, can ameliorate the effects of the stress of food restriction. Four different concentrations of sucrose solutions
were presented to LE and DI rats under the food-restricted condition. In both strains, an 8% sucrose solution was preferred
over 0%, 16%, and 32% concentrations, with DI rats consuming more of this concentration than LE rats. Thus, when DI rats had
the opportunity of maintaining glucose homeostasis by exogenous supplements, they maintained body weight, displayed no stomach
pathology, and survived. 相似文献
857.
This study presents two experiments that demonstrate that the memory trace of a tobe-remembered item develops along a dimension
(continuum) from coarse/general to fine/specific. Similarly, forgetting is shown to be a reverse movement along this dimension
from fine to coarse, as increasingly less fine attributes are lost. The attribute acquisition pattern of this Progressively
Finer Attributes Theory is robust and predictable, valid for experimentally unstructured (Experiment 2) as well as experimentally
structured (Experiment 1) material. 相似文献
858.
William H. Hendrix Barbara A. Spencer Gail S. Gibson 《Journal of business and psychology》1994,9(2):103-128
The purpose of this research is to examine separately for males and females, the effects of different sources of job and life stress on the emotional and physical well-being of those individuals, and in turn on absenteeism. Results using a sample of 170 males and 204 females indicated that females experienced higher levels of job stress, absenteeism, and poorer emotional well-being. Patterns of relationships for males and females were similar, however, the data suggest that sex moderates the effects of different sources of stress on emotional and physical well-being and absenteeism. The model developed as a part of this research was more complicated for females than for males. 相似文献
859.
CAROL H. CANTRELL 《希帕蒂亚:女权主义哲学杂志》1994,9(3):225-238
In Woman and Nature: The Roaring Inside Her, Susan Griffin's embedding of language and culture within the natural world implicitly offers a critique of widespread assumptions, shared by many feminists, that language belongs only to the powerful and that it is inherendy violent. Griffin's depiction of the process through which women come to speech is illuminated by V. N. VofosHnov's work on the multiaccentuakty of language and by Trinh Minh'ha's characterizations of oral traditions. Both authors stress the constant re-creation of language by speakers and listeners. 相似文献
860.
This study examined relations among spelling performance and students' beliefs about spelling, including self-efficacy for spelling ability, outcome expectancy for spelling, and attributions for good spelling across grades 4, 7, and 10. Spelling self-efficacy remained relatively constant across grades. Spelling outcome expectancies for adult life and school declined across grades, as did effort and ability attributions for spelling success, with a disproportional decrease in ability attributions between grades 4 and 7. Self-efficacy was the strongest predictor of spelling performance at all grade levels; attribution for ability entered into the regression for grade 4 students, while outcome expectancies for school and writing were more important in grades 7 and 10. Cluster analyses on the grade 10 sample showed that students with high efficacy as spellers and high outcome expectancy of spelling for writing were the best spellers, with the highest performance reserved for those who attributed good spelling more to effort than ability. The impact of spelling instruction on developing beliefs is discussed. 相似文献