全文获取类型
收费全文 | 3830篇 |
免费 | 688篇 |
国内免费 | 462篇 |
专业分类
电工技术 | 536篇 |
综合类 | 660篇 |
化学工业 | 29篇 |
金属工艺 | 14篇 |
机械仪表 | 103篇 |
建筑科学 | 338篇 |
矿业工程 | 64篇 |
能源动力 | 67篇 |
轻工业 | 41篇 |
水利工程 | 85篇 |
石油天然气 | 9篇 |
武器工业 | 44篇 |
无线电 | 552篇 |
一般工业技术 | 410篇 |
冶金工业 | 73篇 |
原子能技术 | 1篇 |
自动化技术 | 1954篇 |
出版年
2024年 | 57篇 |
2023年 | 128篇 |
2022年 | 189篇 |
2021年 | 232篇 |
2020年 | 254篇 |
2019年 | 232篇 |
2018年 | 200篇 |
2017年 | 179篇 |
2016年 | 198篇 |
2015年 | 217篇 |
2014年 | 294篇 |
2013年 | 287篇 |
2012年 | 327篇 |
2011年 | 276篇 |
2010年 | 254篇 |
2009年 | 255篇 |
2008年 | 256篇 |
2007年 | 275篇 |
2006年 | 212篇 |
2005年 | 170篇 |
2004年 | 117篇 |
2003年 | 81篇 |
2002年 | 68篇 |
2001年 | 46篇 |
2000年 | 32篇 |
1999年 | 15篇 |
1998年 | 19篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1978年 | 3篇 |
1973年 | 2篇 |
1964年 | 2篇 |
1963年 | 3篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1960年 | 4篇 |
1956年 | 1篇 |
1955年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有4980条查询结果,搜索用时 15 毫秒
71.
目的研究游戏设计中极简主义风格的特点与形成原因。方法以当下游戏产品设计中极简主义设计思想的大量应用为启示,结合当下具有代表性的运用了极简主义设计风格的游戏作品,引入了符号学和游戏心理学等理论模型,分析了极简主义风格在游戏视觉特征以及用户体验特征中的体现与意义,并且总结了造成游戏中极简主义设计风格大量出现的环境因素。结论极简主义风格在游戏设计中的流行是受到极简主义设计风格自身的特点和市场用户等环境因素的综合影响。极简主义风格能够很好地与游戏设计的需求相契合,其简洁直观、注重展现游戏产品本质内涵的特征,让它更能够适应游戏设计领域与市场需求的大环境,并且将会对游戏设计领域产生巨大影响。 相似文献
72.
从标准经济学属性上,团体标准是介于事实标准和正式标准之间的一类标准.如何协调好事实标准和正式标准之间的选择关系是团体标准微观层面高效的关键.本文基于"囚徒困境"经典双人博弈模型,构建三阶段协调博弈模型分析团体标准在演化过程中事实标准与正式标准的协调选择问题.研究表明,在已知未来正式标准(即团体标准)优于事实标准以及正式标准的绩效高于事实标准的前提下,低折现和参与者缺乏耐心能够促成尽早"合作".在此基础上,本文基于实际给出提高团体标准收益预期、加快标准版本更新速率和重视"小"企业等政策建议. 相似文献
73.
TAO Jun ZHONG Xiao & LU YiFei Key Laboratory of Computer Network Information Integration Southeast University Ministry of Education Nanjing China School of Computer Science Engineering 《中国科学:信息科学(英文版)》2011,(1):12-22
The flow and congestion control methods based on one-shot game model with non-cooperative game theory can explain the non-cooperative behavior of Internet users.However,the low effciency of equilibrium solutions affects their utility.Here the behavior of flow and congestion control based on infinitely repeated game models is addressed;the repeated and infinitely repeated flow and congestion control game model is presented; the existence and optimization of the Nash equilibrium point are proved;the discount ... 相似文献
74.
James Pita Milind Tambe Fernando Ordóñez Sarit Kraus 《Artificial Intelligence》2010,174(15):1142-1171
How do we build algorithms for agent interactions with human adversaries? Stackelberg games are natural models for many important applications that involve human interaction, such as oligopolistic markets and security domains. In Stackelberg games, one player, the leader, commits to a strategy and the follower makes her decision with knowledge of the leader's commitment. Existing algorithms for Stackelberg games efficiently find optimal solutions (leader strategy), but they critically assume that the follower plays optimally. Unfortunately, in many applications, agents face human followers (adversaries) who — because of their bounded rationality and limited observation of the leader strategy — may deviate from their expected optimal response. In other words, human adversaries' decisions are biased due to their bounded rationality and limited observations. Not taking into account these likely deviations when dealing with human adversaries may cause an unacceptable degradation in the leader's reward, particularly in security applications where these algorithms have seen deployment. The objective of this paper therefore is to investigate how to build algorithms for agent interactions with human adversaries.To address this crucial problem, this paper introduces a new mixed-integer linear program (MILP) for Stackelberg games to consider human adversaries, incorporating: (i) novel anchoring theories on human perception of probability distributions and (ii) robustness approaches for MILPs to address human imprecision. Since this new approach considers human adversaries, traditional proofs of correctness or optimality are insufficient; instead, it is necessary to rely on empirical validation. To that end, this paper considers four settings based on real deployed security systems at Los Angeles International Airport (Pita et al., 2008 [35]), and compares 6 different approaches (three based on our new approach and three previous approaches), in 4 different observability conditions, involving 218 human subjects playing 2960 games in total. The final conclusion is that a model which incorporates both the ideas of robustness and anchoring achieves statistically significant higher rewards and also maintains equivalent or faster solution speeds compared to existing approaches. 相似文献
75.
数独基于规则的逐步枚举算法设计 总被引:1,自引:0,他引:1
给出了数独(Sudoku)的6条性质,并在此基础上提出了6条推理规则,然后结合空格填写的一个一组,两个一组及更多个一组的枚举算法,在枚举中进行推理.使推理和枚举结合起来,对有唯一解的数独问题,其求解速度比回溯法快得多,同时也能完成许多数独软件无法进行推理计算的数独难题.用两个数独难题进行验证,表明该方法十分有效. 相似文献
76.
利润-CVaR准则下的二级供应链定价与订货策略研究 总被引:1,自引:0,他引:1
传统的定价与订货策略研究多是建立在风险中性的假设之上,近来也有利用风险度量CVaR研究风险厌恶对库存的影响.因此,以期望利润和CVaR的加权平均为目标函数,研究零售商的订货策略,并在此基础上研究上游供应商的定价策略.这样的利润-CVaR目标既反映了决策者追求高利润的愿望,又反映了其对潜在风险的控制. 相似文献
77.
This study investigated the effectiveness of massive multiplayer online role‐playing game (MMORPG)‐based (massive multiplayer online role‐playing game) instruction in elementary English education. The effectiveness of the MMORPG program was compared with face‐to‐face instruction and the independent variables (gender, prior knowledge, motivation for learning, self‐directed learning skills, computer skills, game skills, computer capacity, network speed, and computer accessibility) were examined to see how accurately achievement was predicted in MMORPG instruction. The results indicated that students studying English utilizing online role‐playing games showed higher scores in areas of listening, reading, and writing than those who attended face‐to‐face instruction classes. It was also found that prior knowledge, motivation for learning, and network speed were factors affecting achievement in English learning. These findings suggest that MMORPGs can play an important role in improving English communicative skills. 相似文献
78.
Online game is the most popular entertainment application in the virtual world and online gamers demonstrate high attachment to playing online games. Previous studies have linked to the numerous negative outcomes in playing online games. The factors contribute to the negative consequences on using online game have been relatively neglected. The purpose of this study is to explore the impact of perceived risk, intangibility, gender and age (adolescent/adult) difference on online game playing consequences and intentions. Past usage frequency is also made to look into the influence additional purchase intention. A total of 1418 useful questionnaires (including 1018 from public interview and 400 from online questionnaire feedback) were collected for final data analysis. The results demonstrated the important roles that time risk, psychological risk, financial risk, physical intangibility, mental intangibility and generality play on the negative consequences associated with online game playing. The results also indicated that male and adolescent individuals spent much more time on online game and intented to act the entertainment more than females and adults did. Finally, past online game playing frequency was showed to be a positive predictor of future online game playing intention. 相似文献
79.
The present study investigates the impact of the experience of role playing a violent character in a video game on attitudes towards violent crimes and criminals. People who played the violent game were found to be more acceptable of crimes and criminals compared to people who did not play the violent game. More importantly, interaction effects were found such that people were more acceptable of crimes and criminals outside the game if the criminals were matched with the role they played in the game and the criminal actions were similar to the activities they perpetrated during the game. The results indicate that people’s virtual experience through role-playing games can influence their attitudes and judgments of similar real-life crimes, especially if the crimes are similar to what they conducted while playing games. Theoretical and practical implications are discussed. 相似文献
80.
高金燕 《数码设计:surface》2010,(1):286-288
游戏是一种古老的社会文化现象,自从有了人类就有了游戏。随着人类社会的发展、经济和科技水平的不断上升,游戏的概念和内涵也不再是跳皮筋、踢毽子等民间游戏活动。一种承载着更多经济、科技和文化内涵的游戏行为——电子游戏正在渗透到人们的生活中,人们认识到它更多的社会功能和价值,这种社会功能和价值因为游戏的内容、形式以及物质载体的巨大变化而形成了民间游戏和电子游戏的很大差异。 相似文献