全文获取类型
收费全文 | 993篇 |
免费 | 196篇 |
国内免费 | 118篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 24篇 |
2021年 | 24篇 |
2020年 | 62篇 |
2019年 | 49篇 |
2018年 | 61篇 |
2017年 | 46篇 |
2016年 | 53篇 |
2015年 | 36篇 |
2014年 | 44篇 |
2013年 | 130篇 |
2012年 | 36篇 |
2011年 | 48篇 |
2010年 | 29篇 |
2009年 | 62篇 |
2008年 | 75篇 |
2007年 | 73篇 |
2006年 | 52篇 |
2005年 | 56篇 |
2004年 | 45篇 |
2003年 | 46篇 |
2002年 | 51篇 |
2001年 | 32篇 |
2000年 | 28篇 |
1999年 | 15篇 |
1998年 | 9篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 8篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有1307条查询结果,搜索用时 140 毫秒
931.
932.
Hatem Masri Fouad Ben Abdelaziz Houda Alaya 《Journal of Multi-Criteria Decision Analysis》2016,23(1-2):3-14
This paper addresses a multi‐objective stochastic vehicle routing problem where several conflicting objectives such as the travel time, the number of vehicles in use and the probability of an accident are simultaneously minimized. We suppose that demands and travel durations are of a stochastic nature. In order to build a certainty equivalent program to the multi‐objective stochastic vehicle routing problem, we propose a solution strategy based on a recourse approach, a chance‐constrained approach and a goal‐programming approach. The resulting certainty equivalent program is solved to optimality using CPLEX. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
933.
934.
通过对502名11岁城市青少年为期2年的追踪调查,考察了青少年早期内化问题发展的稳定性及母亲教养对1年后青少年内化问题的预测.结果发现:(1)青少年早期的内化问题具有较高的稳定性,与男青少年相比,女青少年保持较高的内化问题水平;(2)母亲控制惩罚教养可以正向预测1年后男青少年的内化问题,母亲温情引导可以负向预测女青少年的内化问题.青少年先前的内化问题对母亲教养与其1年后内化问题之间关系的调节作用存在性别差异:对于先前内化问题水平较高的男青少年而言,母亲较高的温情引导和控制惩罚教养正向预测其1年后的内化问题;对于先前内化问题水平较高的女青少年而言,母亲较多的温情引导则负向预测其1年后的内化问题. 相似文献
935.
Anti-Autonomism Defended: A Reply to Hill 总被引:1,自引:0,他引:1
Stephen Maitzen 《Philosophia》2008,36(4):567-574
In the current issue of this journal, Scott Hill critiques some of my work on the “is”-“ought” controversy, the Hume-inspired
debate over whether an ethical conclusion can be soundly, or even validly, derived from only non-ethical premises. I’ve argued
that it can be; Hill is unconvinced. I reply to Hill’s critique, focusing on four key questions to which he and I give different
answers.
相似文献
Stephen MaitzenEmail: |
936.
The electrophysiological correlates of successful insight problem solving (Chinese logogriphs) were studied in 18 healthy subjects using high-density event-related potentials (ERPs). A new experimental paradigm (learning-testing model) was adopted in order to make subjects find a solution on their own initiative rather than receive an answer passively. Results showed that Successful guessed logogriphs elicited a more positive ERP deflection (P200-600) than did Unsuccessful guessed logogriphs in the time window from 200 to 600 ms after onset of the stimuli. Subsequently Successful logogriphs elicited a more negative ERP deflection than did Unsuccessful logogriphs in the time windows of 1500-2000 ms (N1500-2000) and 2000-2500 ms (N2000-2500). Maps of the P200-600 showed strong activity in the midline parieto-occipital scalp regions. Dipole analysis localized the generator of P200-600 in the left superior temporal gyrus and parietotemporo-occipital cortex areas. The N1500-2000 and N2000-2500 had a distinct activation over left frontal scalp regions. Dipole analysis localized the generator of the N1500-2000 in the anterior cingulate cortex (ACC) and the N2000-2500 in the posterior cingulate cortex (PCC). This result indicates that the parietotemporo-occipital cortex areas might be involved in forming rich associations in the early stage of successful logogriph solving. Then, the ACC might play an important role in the breaking mental set and the forming of novel associations. At last, "Aha" feeling might activate the PCC. 相似文献
937.
The goals of this study are to evaluate a relatively novel learning environment, as well as to seek greater understanding of why human tutoring is so effective. This alternative learning environment consists of pairs of students collaboratively observing a videotape of another student being tutored. Comparing this collaboratively observing environment to four other instructional methods—one-on-one human tutoring, observing tutoring individually, collaborating without observing, and studying alone—the results showed that students learned to solve physics problems just as effectively from observing tutoring collaboratively as the tutees who were being tutored individually. We explain the effectiveness of this learning environment by postulating that such a situation encourages learners to become active and constructive observers through interactions with a peer. In essence, collaboratively observing combines the benefit of tutoring with the benefit of collaborating. The learning outcomes of the tutees and the collaborative observers, along with the tutoring dialogues, were used to further evaluate three hypotheses explaining why human tutoring is an effective learning method. Detailed analyses of the protocols at several grain sizes suggest that tutoring is effective when tutees are independently or jointly constructing knowledge: with the tutor, but not when the tutor independently conveys knowledge. 相似文献
938.
939.
Research suggests that including leisure items in the attention condition of a functional analysis may produce engagement that masks sensitivity to attention. In this study, 4 individuals' initial functional analyses indicated that behavior was maintained by nonsocial variables (n = 3) or by attention (n = 1). A preference assessment was used to identify items for subsequent functional analyses. Four conditions were compared, attention with and without leisure items and control with and without leisure items. Following this, either high- or low-preference items were included in the attention condition. Problem behavior was more probable during the attention condition when no leisure items or low-preference items were included, and lower levels of problem behavior were observed during the attention condition when high-preference leisure items were included. These findings suggest how preferred items may hinder detection of behavioral function. 相似文献
940.
Joop Leo 《Journal of Philosophical Logic》2008,37(4):353-385
In the ordinary way of representing relations, the order of the relata plays a structural role, but in the states themselves such an order often does not seem to be intrinsically present. An alternative way to represent relations makes use of positions for the arguments. This is no problem for the love relation, but for relations like the adjacency relation and cyclic relations, different assignments of objects to the positions can give exactly the same states. This is a puzzling situation. The question is what is the internal structure of relations? Is the use of positions still justified, and if so, what is their ontological status? In this paper mathematical models for relations are developed that provide more insight into the structure of relations “out there” in the real world. 相似文献