全文获取类型
收费全文 | 13579篇 |
免费 | 1375篇 |
国内免费 | 1048篇 |
专业分类
电工技术 | 839篇 |
综合类 | 1794篇 |
化学工业 | 436篇 |
金属工艺 | 199篇 |
机械仪表 | 614篇 |
建筑科学 | 844篇 |
矿业工程 | 338篇 |
能源动力 | 308篇 |
轻工业 | 842篇 |
水利工程 | 402篇 |
石油天然气 | 212篇 |
武器工业 | 194篇 |
无线电 | 1069篇 |
一般工业技术 | 911篇 |
冶金工业 | 1211篇 |
原子能技术 | 45篇 |
自动化技术 | 5744篇 |
出版年
2024年 | 34篇 |
2023年 | 138篇 |
2022年 | 246篇 |
2021年 | 321篇 |
2020年 | 367篇 |
2019年 | 359篇 |
2018年 | 332篇 |
2017年 | 375篇 |
2016年 | 409篇 |
2015年 | 468篇 |
2014年 | 684篇 |
2013年 | 912篇 |
2012年 | 794篇 |
2011年 | 894篇 |
2010年 | 796篇 |
2009年 | 811篇 |
2008年 | 833篇 |
2007年 | 1070篇 |
2006年 | 898篇 |
2005年 | 803篇 |
2004年 | 714篇 |
2003年 | 668篇 |
2002年 | 595篇 |
2001年 | 482篇 |
2000年 | 349篇 |
1999年 | 323篇 |
1998年 | 232篇 |
1997年 | 203篇 |
1996年 | 141篇 |
1995年 | 126篇 |
1994年 | 149篇 |
1993年 | 91篇 |
1992年 | 59篇 |
1991年 | 49篇 |
1990年 | 51篇 |
1989年 | 33篇 |
1988年 | 25篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 18篇 |
1983年 | 17篇 |
1982年 | 16篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1966年 | 8篇 |
1955年 | 7篇 |
1954年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Two experiments involving 99 undergraduate participants sought to examine the influence of mood states on encoding speed within lexical decision and pronunciation tasks. Mood states were measured naturalistically in Experiment 1 and manipulated in Experiment 2. Stimuli consisted of nouns representing useful (e.g., food) and nonuseful (e.g., lint) objects. Mood states had no implications for initial encoding speed. However, when the same words were presented a 2nd time (i.e., repeated), happy individuals displayed a tendency to encode useful words faster than nonuseful ones. Thus, mood states influenced repetition priming on the basis of stimulus valence. The authors propose that happiness sensitizes individuals to useful or rewarding objects, which in turn creates a stronger memory trace for such stimuli in the future. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
The development of autonomous mobile machines to perform useful tasks in real work environments is currently being impeded
by concerns over effectiveness, commercial viability and, above all, safety. This paper introduces a case study of a robotic
excavator to explore a series of issues around system development, navigation in unstructured environments, autonomous decision
making and changing the behaviour of autonomous machines to suit the prevailing demands of users. The adoption of the Real-Time
Control Systems (RCS) architecture (Albus, 1991) is proposed as a universal framework for the development of intelligent systems. In addition it is explained how the use
of Partially Observable Markov Decision Processes (POMDP) (Kaelbling et al., 1998) can form the basis of decision making in the face of uncertainty and how the technique can be effectively incorporated into
the RCS architecture. Particular emphasis is placed on ensuring that the resulting behaviour is both task effective and adequately
safe, and it is recognised that these two objectives may be in opposition and that the desired relative balance between them
may change. The concept of an autonomous system having “values” is introduced through the use of utility theory. Limited simulation
results of experiments are reported which demonstrate that these techniques can create intelligent systems capable of modifying
their behaviour to exhibit either ‘safety conscious’ or ‘task achieving’ personalities. 相似文献
53.
氧气生产单位保用户用气一旦出现较为紧张的局面时,如何正确处理保安全生产运行、保用户生产、安排抢修时间三者之间的关系,值得关注与研究。 相似文献
54.
55.
介绍了神经网络与线性分组码之间的关系,并在文献[1]的基础上证明了软判决译码与求解能量函数最大值之间的等价性,然后以(7,4,3)汉明码为例介绍了神经网络在循环码硬判决、软判决译码中的应用。 相似文献
56.
Product optimization involves selecting design, manufacturing, and support attributes that can produce the best system. Producibility or manufacturability is the term often used to describe the relative ease of manufacturing a product. In complex systems, productibility optimization is a very difficult process, particularly when the values of many attributes are restricted by constraints. One challenge is to develop more universal producibility metrics for the conceptual design phase when design information is limited and drawings are nondimensional. This paper develops a new method for producibility optimization in conceptual design based on a combination of both decision theoretic and expert system techniques. Decision theoretic techniques provide the means to model the design for producibility problem in a manner that can deal with risk, uncertainty, and user (or corporate) preferences, and can effectively integrate diverse factors to provide a measure of the overall worth of a design. The particular decision theoretic approach employed is based on multi-attribute utility theory. An illustrative example of the methodology is applied to the conceptual design of a structural composite part. 相似文献
57.
58.
59.
One of the main problems faced while configuring or reconfiguring manufacturing systems is to rank alternative designs taking into account all the different aspects involved (both tangible and intangible). For this purpose the Analytic Hierarchy Process (AHP) is a well-known decision making support method that addresses this problem. A major drawback of AHP is that uncertainty in the judgments of the decision makers and the resulting impact on the ranking is not considered. In real situations, however, judgments based on perceived future scenarios are almost always uncertain. To solve this problem in this paper we present the first complete probabilistic extension to the AHP method. The new method provides the decision maker not only with information on the ranking of the alternatives but also the probability that the ranking remains stable even in presence of uncertainty in the judgements. We verified the validity of the new method in a real application developed for the Ferrari racing team. 相似文献
60.