全文获取类型
收费全文 | 43218篇 |
免费 | 1606篇 |
国内免费 | 15篇 |
出版年
2020年 | 378篇 |
2019年 | 432篇 |
2018年 | 704篇 |
2017年 | 700篇 |
2016年 | 838篇 |
2015年 | 585篇 |
2014年 | 603篇 |
2013年 | 2692篇 |
2012年 | 1334篇 |
2011年 | 1305篇 |
2010年 | 680篇 |
2009年 | 663篇 |
2008年 | 996篇 |
2007年 | 983篇 |
2006年 | 862篇 |
2005年 | 2025篇 |
2004年 | 1342篇 |
2003年 | 1091篇 |
2002年 | 826篇 |
2001年 | 1293篇 |
2000年 | 1234篇 |
1999年 | 908篇 |
1998年 | 400篇 |
1997年 | 346篇 |
1992年 | 883篇 |
1991年 | 829篇 |
1990年 | 867篇 |
1989年 | 747篇 |
1988年 | 733篇 |
1987年 | 714篇 |
1986年 | 743篇 |
1985年 | 809篇 |
1984年 | 610篇 |
1983年 | 561篇 |
1982年 | 370篇 |
1981年 | 356篇 |
1979年 | 709篇 |
1978年 | 435篇 |
1977年 | 422篇 |
1976年 | 418篇 |
1975年 | 607篇 |
1974年 | 696篇 |
1973年 | 740篇 |
1972年 | 638篇 |
1971年 | 603篇 |
1970年 | 590篇 |
1969年 | 578篇 |
1968年 | 766篇 |
1967年 | 684篇 |
1966年 | 611篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
301.
Judith M. Lavelle Melbourne F. Hovell M. Patricia West Dennis R. Wahlgren 《Journal of applied behavior analysis》1992,25(4):885-892
The Colorado Occupant Protection Project (COPP) intervention provided police with brief instruction concerning the importance of citations for drivers' failure to use child safety seats and special coupons to accompany citations. Coupons were exchangeable by drivers for a safety seat and brief training in its use, plus a waiver of the $50 citation fine. Over 4.5 years of archival records were employed, using an ABA design and a comparison community to evaluate the program. Few tickets were issued for nonuse of safety seats during the 3-year baseline in either community. Citations for nonuse of safety seats increased to over 50 per month during the intervention period at the test site, whereas rates remained essentially zero at the comparison site. After the COPP intervention was removed at the intervention site, citation rates for nonuse of safety seats decreased to about 15 per month. Differences between intervention conditions and settings were statistically significant. During the intervention, officers were 44 times more likely to write citations than were controls. Results suggested that a behavioral program can increase police citation writing for child protection purposes. 相似文献
302.
A construct validation approach was followed to affirm that 8 physical ability test events were significantly related to two important constructs underlying the job performance of police officers: strength and endurance. A sample of 115 incumbent police officers took 8 physical ability tests and were rated by supervisors on their physical performances in their job. LISREL methods were used to test the model specified, and a reasonable fit was achieved. Portions of the model were tested on an independent sample of 161 applicants; the fit of the model was again acceptable. A nomological network of relationships, in which strength and endurance factors correlated in expected directions with other physiological and demographic variables, was hypothesized and tested. Finally, the data were examined for potential gender differences and bias. Considerable differences were shown between men and women on both test and performance variables, and women would be overpredicted if a common regression line were used for selection purposes. 相似文献
303.
S Streufert R M Pogash J Roache D Gingrich R Landis W Severs L Lonardi A Kantner 《The Journal of applied psychology》1992,77(4):515-524
Adult men (N = 44) participated for 2 days (alcohol vs. placebo treatment) in a double-blind, crossover experiment. Performance on the Digit Symbol Substitution Task (DSST) and a visuomotor (VM) task was measured 4 times each day. On the alcohol-treatment day, data were obtained once during ascending breath alcohol levels (BALs), once during maximal BALs (0.05 or 0.10), and twice during descending BALs. Data were collected at the same time points on the placebo-treatment day. Limited evidence for acute tolerance was obtained with the DSST, but error rates on the VM task were higher during maximal and descending BALs. Error rates remained near placebo values, and participants displayed slightly greater caution, while BALs were ascending. Strategy scores on the VM task exceeded placebo scores during maximal intoxication. Data interpretation is focused on individuals in higher level (e.g., professional) positions. 相似文献
304.
Two studies examined the effects of a reductive treatment versus instruction-based treatments on the generalized reduction of problem behaviors. Each study involved a detailed analysis of multiple problem behaviors performed by school-aged youth with severe intellectual disabilities. The analysis examined the contrasting effects of one of two different positive intervention procedures (teaching a positive alternative behavior or providing additional teacher assistance during instruction) versus blocking and/or verbally reprimanding a problem behavior. The focus of each analysis was on the covariation of multiple problem behaviors within functional response classes. Results of the investigation indicated that when only one member of the response class was blocked, a collateral increase was observed in one or more different problem behaviors from the same response class. Alternatively, when 1 participant was taught a functionally equivalent mand response, all problem behaviors in the response class were reduced. Problem behaviors also were reduced for the remaining participant by presenting antecedent teacher assistance. Implications of the research extend to analysis of covariation within response classes and to procedures that result in generalized reduction of problem behaviors within a response class. 相似文献
305.
Subjects performed a repetitive manual tapping task, attempting to match a given rate of auditory stimulus pulses, first with the pulses audible (synchronization) and then with the pulses turned off (continuation). In different sessions, the interstimulus interval (ISI) was selected from the range 175 to 825 msec in steps of 25 msec, with different ISI values presented in a random order. Across this range of ISI conditions, interresponse intervals (IRIs) exhibited alternating positive bias (too slow) and negative bias (too fast). We interpret this pattern of bias in terms of a discrete, or categorical, timing mechanism in motor timing. Categorical time production can be viewed as extending our conception of the timekeeper in Wing's (Wing & Kristofferson, 1973a, 1973b) two-process model of motor timing and may be related to the system of multiple clocks proposed by Kristofferson (1980) to explain a categorical pattern of variability measures in duration discrimination. 相似文献
306.
In each of two experiments, 2 pigeons received discrimination training in which food reinforcement for key pecking was conditional upon both spatial and temporal cues. In Experiment 1, food was available for periods of 30 s at each of three locations (pecking keys) during trials that lasted 90 s. In Experiment 2, food was available for periods of 15 min at each of four locations (pecking keys) during a 60-min trial. In both experiments, pigeons' key pecking was jointly controlled by the spatial and temporal cues. These data, and other recent experiments, suggest that animals learn relationships between temporal and spatial cues that predict stable patterns of food availability. 相似文献
307.
308.
A previous report on the effect of the day of the full moon on the acting-out behavior of 20 developmentally delayed, institutionalized women showed that on the day of the full moon there were significantly more misbehaviors than on any other day during the lunar period. The records were re-evaluated to assess the frequency of acting-out behaviors on weekends and holidays as contrasted with the balance of the month. This re-evaluation indicated there was no significant difference between the weekends and holidays and the balance of the month (t = 1.14). The results were taken as support of the previous findings that on the day of the full moon there were significantly more misbehaviors than on any other day of the lunar period. 相似文献
309.
Variation of amplitude envelope at stimulus onset has been considered to be of primary importance for distinguishing voiceless affricates from fricatives (e.g., [symbol: see text]). In earlier perceptual experiments, however, variation in amplitude rise time was confounded with variation in frication duration. In two experiments, these variables were independently manipulated, and their individual and combined effects for perception of magnitude of [symbol: see text] were examined. Variation in amplitude rise time alone was not sufficient to signal the voiceless affricate/fricative contrast in these experiments, but variation in frication duration alone was sufficient. 相似文献
310.
M Zivkovi? 《Perceptual and motor skills》1992,75(1):79-90
The quotient of the mean quantitative score on Initial-letter Word-association Test for 193 normal subjects was significantly higher than the quotient of the mean quantitative score of 44 abnormal (psychotic) subjects. This is interpreted as meaning that, in general, the normal subjects have predominantly a positive attitude towards their surrounding world in contradistinction to the abnormal subjects whose attitude was predominantly negative, ambivalent, and repressive. On the other hand, the mean of the quotients of the quantitative scores of the 44 abnormal subjects was higher than the mean of the quotients of the quantitative scores of the normal subjects which suggests increased oral tendencies of the abnormal subjects expressed much as the unwarranted optimism of small children. 相似文献