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   29996篇
  免费   1316篇
  国内免费   15篇
  31327篇
  2020年   417篇
  2019年   472篇
  2018年   664篇
  2017年   609篇
  2016年   708篇
  2015年   503篇
  2014年   654篇
  2013年   2710篇
  2012年   1106篇
  2011年   1092篇
  2010年   775篇
  2009年   758篇
  2008年   1056篇
  2007年   1051篇
  2006年   932篇
  2005年   854篇
  2004年   831篇
  2003年   773篇
  2002年   792篇
  2001年   927篇
  2000年   920篇
  1999年   692篇
  1998年   391篇
  1997年   344篇
  1996年   296篇
  1995年   315篇
  1994年   305篇
  1993年   276篇
  1992年   521篇
  1991年   486篇
  1990年   495篇
  1989年   445篇
  1988年   421篇
  1987年   416篇
  1986年   377篇
  1985年   389篇
  1984年   384篇
  1983年   325篇
  1982年   302篇
  1981年   275篇
  1980年   246篇
  1979年   352篇
  1978年   302篇
  1977年   254篇
  1976年   249篇
  1975年   284篇
  1974年   331篇
  1973年   305篇
  1972年   246篇
  1968年   259篇
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
991.
992.
The question of whether an automatic detection task requires the use of limited-capacity resources was investigated in a series of dual-task experiments. The automatic task required subjects to detect a consistently mapped target digit in a display of letters. This task was paired with a variety of concurrent visual discriminations that could either occur in close proximity to the automatic target or in a disparate display area. The main finding was that accuracy in each task was higher in conditions allowing attention to be shared than when it had to be divided between separate areas. These results indicate that detection of automatic targets depends on the allocation of spatial attention to the target's area.  相似文献   
993.
994.
Two experiments are reported in which the relationship between compliance with “do” and “don't” requests was examined with developmentally disabled children. In Experiment 1, a multiple baseline design across subjects with counterbalanced treatment conditions was used to evaluate a compliance training program composed of four phases: (a) baseline, during which no consequences were delivered for compliance, (b) reinforcement for compliance with one targeted “do” request, (c) reinforcement for compliance with one targeted “don't” request, and (d) follow-up with reinforcement on a variable ratio schedule for compliance with any “do” or “don't” request. Results of probes conducted before and after training within each condition indicated that generalized compliance occurred only with requests of the same type as the target exemplar (“do” or “don't”). In Experiment 2, these results were replicated in a classroom setting. Following collection of baseline probe data on student compliance, a teacher training program was successfully implemented to increase reinforcement of compliance first with one “do” and subsequently with one “don't” request of a target student. Results of multiple baseline probes across “do” and “don't” requests indicated that the teacher generalized and maintained reinforcement of compliance with other requests of the same type and to other students, with a resulting increase in student compliance with the type of requests reinforced. The impact of treatment on both teacher and student behavior was socially validated via consumer ratings. Implications of these findings with respect to response class formation and compliance training programs are discussed.  相似文献   
995.
996.
A procedural theory of eye movement that accounts for main features of the stochastic behavior of eye-fixation durations and direction of movement of saccades in the process of solving arithmetic exercises of addition and subtraction is presented. The best-fitting distribution of fixation durations with a relatively simple theoretical justification consists of a mixture of an exponential distribution and the convolution of two exponential distributions. The eye movements themselves were found to approximate a random walk that fits rather closely in both adult and juvenile subjects the motion postulated by the normative algorithm ordinarily taught in schools. Certain structural features of addition and subtraction exercises, such as the number of columns, the presence or absence of a carry or a borrow, are well known to affect their difficulty. In this study, regressions on such structural variables were found to account for only a relatively small part of the variation in eye-fixation durations.  相似文献   
997.
The concept “impossible figure” is analyzed by formalizing the interpretations of a polyhedral figure by an observer, and defining several types of inconsistency in such interpretations. Tests for these inconsistencies are developed using simple graph theory, and a sufficient condition is established for the feasibility of an interpretation. Finally, techniques are derived for the automatic construction of usual or unusual multibar figures.  相似文献   
998.
An adaptive up-down tracking procedure was used in combination with a visually reinforced head turn response to examine auditory sensitivity for 500, 2000, and 8000-Hz tone bursts in infants 6 to 18 months of age. Six- and 10-month-old infants were tested with headphone presentation of stimuli, while 10-, 14, and 18-month-olds were tested in sound field. Infant threshold estimates for both headphone and sound field were within 15 dB of adult comparisons for all frequencies and age groups. Six-month-olds were significantly less sensitive to the 8000-Hz tone than to either of the lower frequency stimuli, but older infants demonstrated approximately equal sensitivity for all three frequencies tested.  相似文献   
999.
Paper/pencil psychological tests such as the Minnesota Multiphasic Personality Inventory (MMPI) are difficult to complete independently by patients with limited hand function. This paper describes a voice recognition system developed to allow patients with no hand function to take the MMPI independently. Profiles generated by this system are not statistically different from those generated by standard MMPI booklet format. Limitations and possible extensions of the system as it currently exists are discussed.  相似文献   
1000.
Seventy-two normal adult male subjects wrote TAT stories under baseline and either placebo- or marijuana-ingestion conditions. Marijuana subjects received 20 mg. doses of delta-9 tetrahydrocannabinol. The stories were keypunched and content analyzed with the Regressive Imagery Dictionary, which yields a score for primary process content. Results indicate that marijuana, relative to placebo, caused subjects to write stories with a higher proportion of primary process content than they had included in baseline stories.  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