全文获取类型
收费全文 | 17345篇 |
免费 | 2545篇 |
国内免费 | 1835篇 |
专业分类
电工技术 | 650篇 |
技术理论 | 2篇 |
综合类 | 2311篇 |
化学工业 | 361篇 |
金属工艺 | 229篇 |
机械仪表 | 1069篇 |
建筑科学 | 3303篇 |
矿业工程 | 452篇 |
能源动力 | 245篇 |
轻工业 | 224篇 |
水利工程 | 938篇 |
石油天然气 | 253篇 |
武器工业 | 184篇 |
无线电 | 1843篇 |
一般工业技术 | 1113篇 |
冶金工业 | 1005篇 |
原子能技术 | 170篇 |
自动化技术 | 7373篇 |
出版年
2024年 | 52篇 |
2023年 | 283篇 |
2022年 | 614篇 |
2021年 | 590篇 |
2020年 | 652篇 |
2019年 | 560篇 |
2018年 | 506篇 |
2017年 | 600篇 |
2016年 | 657篇 |
2015年 | 746篇 |
2014年 | 971篇 |
2013年 | 1034篇 |
2012年 | 1138篇 |
2011年 | 1260篇 |
2010年 | 1082篇 |
2009年 | 1161篇 |
2008年 | 1222篇 |
2007年 | 1296篇 |
2006年 | 1207篇 |
2005年 | 998篇 |
2004年 | 881篇 |
2003年 | 762篇 |
2002年 | 558篇 |
2001年 | 508篇 |
2000年 | 394篇 |
1999年 | 328篇 |
1998年 | 273篇 |
1997年 | 236篇 |
1996年 | 203篇 |
1995年 | 180篇 |
1994年 | 164篇 |
1993年 | 131篇 |
1992年 | 99篇 |
1991年 | 90篇 |
1990年 | 61篇 |
1989年 | 59篇 |
1988年 | 38篇 |
1987年 | 22篇 |
1986年 | 17篇 |
1985年 | 14篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1965年 | 4篇 |
1964年 | 3篇 |
1959年 | 5篇 |
1957年 | 3篇 |
1956年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
101.
The conditioned cue preference (CCP) task was used to study the information required to discriminate between spatial locations defined by adjacent arms of an 8-arm radial maze. Normal rats learned the discrimination after 3 unreinforced preexposure (PE) sessions and 4 food paired-unpaired training trials. Fimbria-fornix lesions made before, but not after, PE, and hippocampus lesions made at either time, blocked the discrimination, suggesting that the 2 structures processed different information. Lateral amygdala lesions made before PE facilitated the discrimination. This amygdala-mediated interference with the discrimination was the result of a conditioned approach response that did not discriminate between the 2 arm locations. A hippocampus/fimbria-fornix system and an amygdala system process different information about the same learning situation simultaneously and in parallel. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
102.
通过对无锡市运河实验中学改扩建项目的回顾,阐述如何发掘原有校园空间环境的价值,并且通过借鉴中国古典园林的设计手法,使得老校园焕发出新生机。 相似文献
103.
104.
Tetsuya Murai Yoshiharu Sato Germano Resconi Michinori Nakata 《Electronic Notes in Theoretical Computer Science》2003,82(4):186
The concept of granular computing is applied to Aristotle's categorical syllogism. Such kind of reasoning is called granular reasoning in this paper. For the purpose, two operations called zooming in & out are introduced to reconstruct granules of possible worlds. 相似文献
105.
Evgenia Adamopoulou Konstantinos Demestichas Panagiotis Demestichas Michael Theologou 《International Journal of Communication Systems》2008,21(3):311-330
Cognitive radio systems dynamically reconfigure the algorithms and parameters they use, in order to adapt to the changing environment conditions. However, reaching proper reconfiguration decisions presupposes a way of knowing, with high enough assurance, the capabilities of the alternate configurations, especially in terms of achievable transmission capacity and coverage. The present paper addresses this problem, firstly, by specifying a complete process for extracting estimations of the capabilities of candidate configurations, in terms of transmission capacity and coverage, and, secondly, by enhancing these estimations with the employment of a machine learning technique. The technique is based on the use of Bayesian Networks, in conjunction with an effective learning and adaptation strategy, and aims at extracting and exploiting knowledge and experience, in order to reach robust (i.e. stable and reliable) estimations of the configurations' capabilities. Comprehensive results of the proposed method are presented, in order to validate its functionality. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
106.
In today's competitive business environment, it is important that customers are able to obtain their preferred items in the shops they visit, particularly for convenience store chains such as 7–Eleven where popular items are expected to be readily available on the shelves of the stores for buyers. To minimize the cost of running such store chains, it is essential that stocks be kept to a minimum and at the same time large varieties of popular items are available for customers. In this respect, the replenishment system needs to be able to cope with the taxing demands of minimal inventory but at the same time keeping large varieties of needed items. This paper proposes a replenishment system which is able to respond to the fluctuating demands of customers and provide a timely supply of needed items in a cost–effective way. The proposed system embraces the principle of fuzzy logic which is able to deal with uncertainties by virtue of its fuzzy rules reasoning mechanism, thereby leveraging the responsiveness of the entire replenishment system for the chain stores. To validate the feasibility of the approach, a case study has been conducted in an emulated environment with promising results. 相似文献
107.
Mou Weimin; Biocca Frank; Owen Charles B.; Tang Arthur; Xiao Fan; Lim Lynette 《Canadian Metallurgical Quarterly》2004,10(4):238
In 3 experiments, the authors investigated spatial updating in augmented reality environments. Participants learned locations of virtual objects on the physical floor. They were turned to appropriate facing directions while blindfolded before making pointing judgments (e.g., "Imagine you are facing X. Point to Y"). Experiments manipulated the angular difference between the learning heading and the imagined heading and between the actual heading and the imagined heading. The effect of actual-imagined on pointing latency was observed for naive users but not for users with brief training or instructions concerning the fact that objects can move with body movements. The results indicated that naive users used an environment-stabilized reference frame to access information arrays, but with experience and instruction the nature of the representation changed from an environment stabilized to a body stabilized reference frame. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
Theoretical and empirical findings regarding the mind-body relation and its integration within a concept of the self-as-person lead to certain therapeutic implications and applications. The mind-set of the analyst or psychotherapist regarding the integration of mind-body can have important reverberations, which can dictate decisions for therapeutic intervention and management. Implications for conceptualizing technical modifications in analytic therapy are suggested. Conceptualization of mind and brain operating as an integrated and functional unity contribute to better understanding aspects of mental functioning that remain beyond the reach of conscious awareness and direct therapeutic processing. Particular attention is paid to the issue of combining medications clinically with psychotherapy and psychoanalysis. Future integration of psychoanalysis with advancing trends in therapeutic intervention and with rapidly expanding neurobiological understanding of mental actions as related to brain activity may require a deepening awareness of complexities of the mind-body relation and a more analytically meaningful resolution of the problem. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
U. Bodenhofer 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2003,7(4):220-227
This paper is devoted to a general concept of openness and closedness with respect to arbitrary fuzzy relations – along with
appropriate opening and closure operators. It is shown that the proposed framework unifies existing concepts, in particular,
the one for fuzzy preorderings as well as the triangular norm-based approach to fuzzy mathematical morphology.
The author acknowledges support of the K
plus Competence Center Program which is funded by the Austrian Government, the Province of Upper Austria, and the Chamber of Commerce
of Upper Austria. 相似文献
110.
Learning and memory of novel spatial configurations aids behaviors such as visual search through an implicit process called contextual cuing (M. M. Chun & Y. Jiang, 1998). The present study provides rigorous tests of the implicit nature of contextual cuing. Experiment 1 used a recognition test that closely matched the learning task, confirming that memory traces of predictive spatial context were not accessible to conscious retrieval. Experiment 2 gave explicit instructions to encode visual context during learning, but learning was not improved and conscious memory remained undetectable. Experiment 3 illustrates that memory traces for spatial context may persist for at least 1 week, suggesting a long-term component of contextual cuing. These experiments indicate that the learning and memory of spatial context in the contextual cuing task are indeed implicit. The results have implications for understanding the neural substrate of spatial contextual learning, which may depend on an intact medial temporal lobe system that includes the hippocampus (M. M. Chun & E. A. Phelps, 1999). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献