全文获取类型
收费全文 | 4232篇 |
免费 | 2477篇 |
国内免费 | 130篇 |
专业分类
6839篇 |
出版年
2024年 | 6篇 |
2023年 | 37篇 |
2022年 | 67篇 |
2021年 | 168篇 |
2020年 | 212篇 |
2019年 | 625篇 |
2018年 | 519篇 |
2017年 | 618篇 |
2016年 | 593篇 |
2015年 | 509篇 |
2014年 | 440篇 |
2013年 | 603篇 |
2012年 | 304篇 |
2011年 | 283篇 |
2010年 | 232篇 |
2009年 | 201篇 |
2008年 | 148篇 |
2007年 | 190篇 |
2006年 | 198篇 |
2005年 | 173篇 |
2004年 | 144篇 |
2003年 | 142篇 |
2002年 | 115篇 |
2001年 | 101篇 |
2000年 | 79篇 |
1999年 | 46篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 9篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有6839条查询结果,搜索用时 15 毫秒
91.
Brief multiple-stimulus-without-replacement (MSWO) preference assessments were conducted with 3 adolescent boys with emotional-behavioral disorders in the context of their public school educational program. The reinforcing effects of stimuli identified as high, medium, and low preference were then evaluated using an alternating treatments design in which, following an initial baseline, stimuli were delivered contingent on on-task behavior. High-preference stimuli produced the highest percentages of on-task behavior for all 3 participants. 相似文献
92.
Hughes CE Sigmon SC Pitts RC Dykstra LA 《Journal of the experimental analysis of behavior》2005,83(3):281-296
Key pecking by 3 pigeons was maintained by a multiple fixed-ratio 10, fixed-ratio 30, fixed-ratio 90 schedule of food presentation. Components differed with respect to amount of reinforcement, such that the unit price was 10 responses per 1-s access to food. Acute administration of morphine, l-methadone, and cocaine dose-dependently decreased overall response rates in each of the components. When a rate decreasing dose of morphine was administered daily, tolerance, as measured by an increase in the dose that reduced response rates to 50% of control (i.e., the ED50 value), developed in each of the components; however, the degree of tolerance was smallest in the fixed-ratio 90 component (i.e., the ED50 value increased the least). When the l-methadone dose-effect curve was redetermined during the chronic morphine phase, the degree of cross-tolerance conferred to l-methadone was similar across components, suggesting that behavioral variables may not influence the degree of cross-tolerance between opioids. During the chronic phase, the cocaine dose-effect curve shifted to the right for 2 pigeons and to the left for 1 pigeon, which is consistent with predictions based on the lack of pharmacological similarity between morphine and cocaine. When the morphine, l-methadone, and cocaine dose-effect curves were redetermined after chronic morphine administration ended, the morphine and l-methadone ED50s replicated those obtained prior to chronic morphine administration. The morphine data suggest that the fixed-ratio value (i.e., the absolute output) determines the degree of tolerance and not the unit price. 相似文献
93.
Sealey DM Sumpter CE Temple W Foster TM 《Journal of the experimental analysis of behavior》2005,84(1):19-35
To examine the effects on concurrent performance of independent manipulations of response-unit duration and number, 6 hens were exposed to concurrent second-order schedules of reinforcement. Each first-order operant unit required completion of a fixed-ratio schedule within the time specified by a fixed-interval schedule, with one further response completing the fixed-interval schedule. The fixed-ratio and fixed-interval requirements comprising the first-order operant units were systematically and independently varied under three pairs of concurrent variable-interval schedules to produce differences in the first-order response and duration requirements (response and duration differentials). These manipulations produced consistent changes in response, time, and operant-unit biases. A 1:4 response differential biased the time and operant-unit measures towards the smaller fixed ratio, but to a degree less than the imposed response differential. The response-based biases favored the larger fixed ratio. Duration differentials of 4:1 and 8:1 biased the response and operant-unit measures towards the shorter fixed interval, again less than the imposed duration differential, but the time biases remained close to zero. Both sorts of differentials acted to bias operant-unit completions more systematically than the other measures, but undermatching to the differentials occurred. The undermatching appears to have arisen from a pattern of fix and sample (in which visits to the less preferred alternative involved only a single completed operant unit) under combinations of unequal operant-unit requirements and reinforcer rates. The response and time bias measures appeared to arise as by-products of the changes in operant-unit completions. 相似文献
94.
Kalenscher T Güntürkün O Calabrese P Gehlen W Kalt T Diekamp B 《Journal of the experimental analysis of behavior》2005,84(3):521-535
Working memory, the ability to temporarily retain task-relevant information across a delay, is frequently investigated using delayed matching-to-sample (DMTS) or delayed Go/No-Go tasks (DGNG). In DMTS tasks, sample cues instruct the animal which type of response has to be executed at the end of a delay. Typically, performance decreases with increasing delay duration, indicating that working memory fades across a delay. However, no such performance decrease has been found when the sample cues exist of present vs. absent stimuli, suggesting that pigeons do not rely on working memory, but seem to respond by default in those trials. We trained 3 pigeons in a DGNG task and found a similar default response pattern: The diverging slopes of the retention functions on correct Go and No-Go trials suggested that pigeons by default omitted their response following No-Go stimuli, but actively retained task-relevant information across the delay for successful responses on Go trials. We conducted single-cell recordings in the avian nidopallium caudolaterale, a structure comparable to the mammalian prefrontal cortex. On Go trials, many neurons displayed sustained elevated activity during the delay preceding the response, replicating previous findings and suggesting that task-relevant information was neurally represented and maintained across the delay. However, the same units did not show enhanced delay activity preceding correct response suppressions in No-Go trials. This activation-inactivation pattern presumably constitutes a neural correlate of the default response strategy observed in the DGNG task. 相似文献
95.
McKerchar TL Zarcone TJ Fowler SC 《Journal of the experimental analysis of behavior》2005,84(3):339-356
Recent progress in mouse genetics has led to an increased interest in developing procedures for assessing mouse behavior, but relatively few of the behavioral procedures developed involve positively reinforced operant behavior. When operant methods are used, nose poking, not lever pressing, is the target response. In the current study differential acquisition of milk-reinforced lever pressing was observed in five inbred strains (C57BL/6J, DBA/2J, 129X1/SvJ, C3H/HeJ, and BALB/cJ) and one outbred stock (CD-1) of mice. Regardless of whether one or two levers (an "operative" and "inoperative" lever) were in the operant chamber, a concomitant variable-time fixed-ratio schedule of milk reinforcement established lever pressing in the majority of mice within two 120-min sessions. Substantial differences in lever pressing were observed across mice and between procedures. Adding an inoperative lever retarded acquisition in C57BL/6J, DBA/2J, 129X1/SvJ, and C3H/HeJ mice, but not in CD-1 and BALB/cJ mice. Locomotor activity was positively correlated with number of lever presses in both procedures. Analyses of durations of the subcomponents (e.g., time to move from hopper to lever) of operant behavior revealed further differences among the six types of mice. Together, the data suggest that appetitively reinforced lever pressing can be acquired rapidly in mice and that a combination of procedural, behavioral, and genetic variables contributes to this acquisition. 相似文献
96.
Abreu-Rodrigues J Lattal KA dos Santos CV Matos RA 《Journal of the experimental analysis of behavior》2005,83(2):147-168
Experiment 1 investigated the controlling properties of variability contingencies on choice between repeated and variable responding. Pigeons were exposed to concurrent-chains schedules with two alternatives. In the REPEAT alternative, reinforcers in the terminal link depended on a single sequence of four responses. In the VARY alternative, a response sequence in the terminal link was reinforced only if it differed from the n previous sequences (lag criterion). The REPEAT contingency generated low, constant levels of sequence variation whereas the VARY contingency produced levels of sequence variation that increased with the lag criterion. Preference for the REPEAT alternative tended to increase directly with the degree of variation required for reinforcement. Experiment 2 examined the potential confounding effects in Experiment 1 of immediacy of reinforcement by yoking the interreinforcer intervals in the REPEAT alternative to those in the VARY alternative. Again, preference for REPEAT was a function of the lag criterion. Choice between varying and repeating behavior is discussed with respect to obtained behavioral variability, probability of reinforcement, delay of reinforcement, and switching within a sequence. 相似文献
97.
师生关系与中小学生学校适应性的关系 总被引:17,自引:3,他引:14
师生关系作为儿童人际关系的一部分,是儿童社会化的重要内容,对儿童的学校适应产生重要影响。本研究运用问卷法、访谈法等对6个年级867名中小学生进行测查,以了解中小学生师生关系对学生学校适应性的影响。结果表明:(1)中小学生学校适应性与师生关系之间存在显著正相关;(2)师生关系是影响学生学校适应性的重要因素。其影响程度从大到小依次为:亲密性、主动性、合作性;年龄也影响学生的学校适应性,但程度较小。 相似文献
98.
Kimberly?A.?SchreckEmail author James?A.?Mulick Johannes?Rojahn 《Journal of child and family studies》2005,14(1):101-109
Wide discrepancies exist concerning the reported occurrence of sleep problems for elementary school children. We describe parental perception of sleep problem behavior in elementary school aged children 5–12 years. Approximately 4% of parents reported their children experienced significant global sleep problems serious enough to adversely affect family functioning. Significant specific sleep problems reported by parents occurred for approximately 9–14% of the children in the sample. These ranges were in the low end of the ranges of sleep problems reported in previous literature for this age group. 相似文献
99.
Kimber?W.?MalmgrenEmail author Joseph?C.?Gagnon 《Journal of child and family studies》2005,14(2):299-312
We examined the school mobility of a cross-sectional sample of 70 secondary-age youth with emotional disturbance (ED). Data were collected through an archival review of school records. Students’ school mobility histories were examined in terms of the overall number of schools attended in the elementary school years, as well as the timing of the moves that were made. Findings indicate that sample students experienced high rates of school mobility with 66% having changed schools at least once by the end of 2nd grade and 89% having changed schools at least once by the end of 5th grade. Strategies for minimizing school mobility and the impact of high rates of school mobility are reviewed. 相似文献
100.
Barry?A.?HongEmail author Gerald?Leventhal Richard?J.?Seime 《Journal of clinical psychology in medical settings》2005,12(3):247-256
This paper highlights the role of the Association of Medical School Psychologists (AMSP) as a bridge between academic medicine and psychology. AMSP’s affiliation with Division 12 of the American Psychological Association is discussed, but the primary focus is AMSP’s affiliation with the Association of American Medical Colleges (AAMC) and the AAMC’s Council of Academic Societies (CAS). The history, structure, activities, and goals of AAMC and CAS are examined. AMSP’s affiliation with AAMC is important for psychologists in medical schools and academic medical centers, and for psychology in general, because AAMC is the major voice of academic medicine in the US. AAMC activities affect medical education at all levels, as well as research and health services at academic medical centers, and health care policy at the national level. AMSP’s dual affiliation with AAMC’s CAS and APA’s Society of Clinical Psychology will increase psychology’s visibility and influence in academic medical centers and enhance the two-way flow of ideas and information between academic medicine and psychology. 相似文献