全文获取类型
收费全文 | 573751篇 |
免费 | 49406篇 |
国内免费 | 29288篇 |
专业分类
电工技术 | 39626篇 |
技术理论 | 76篇 |
综合类 | 69103篇 |
化学工业 | 66600篇 |
金属工艺 | 23875篇 |
机械仪表 | 33438篇 |
建筑科学 | 77189篇 |
矿业工程 | 30308篇 |
能源动力 | 19134篇 |
轻工业 | 36383篇 |
水利工程 | 26999篇 |
石油天然气 | 26433篇 |
武器工业 | 6802篇 |
无线电 | 38436篇 |
一般工业技术 | 49243篇 |
冶金工业 | 30645篇 |
原子能技术 | 6110篇 |
自动化技术 | 72045篇 |
出版年
2024年 | 2254篇 |
2023年 | 6558篇 |
2022年 | 12573篇 |
2021年 | 15531篇 |
2020年 | 16138篇 |
2019年 | 12979篇 |
2018年 | 12460篇 |
2017年 | 15478篇 |
2016年 | 18168篇 |
2015年 | 19688篇 |
2014年 | 35126篇 |
2013年 | 31995篇 |
2012年 | 40390篇 |
2011年 | 43051篇 |
2010年 | 33172篇 |
2009年 | 34203篇 |
2008年 | 31695篇 |
2007年 | 39918篇 |
2006年 | 36648篇 |
2005年 | 31743篇 |
2004年 | 26717篇 |
2003年 | 23510篇 |
2002年 | 19458篇 |
2001年 | 16263篇 |
2000年 | 13864篇 |
1999年 | 11285篇 |
1998年 | 8511篇 |
1997年 | 7446篇 |
1996年 | 6486篇 |
1995年 | 5555篇 |
1994年 | 4819篇 |
1993年 | 3537篇 |
1992年 | 3068篇 |
1991年 | 2214篇 |
1990年 | 1916篇 |
1989年 | 1741篇 |
1988年 | 1297篇 |
1987年 | 850篇 |
1986年 | 682篇 |
1985年 | 548篇 |
1984年 | 491篇 |
1983年 | 364篇 |
1982年 | 305篇 |
1981年 | 268篇 |
1980年 | 218篇 |
1979年 | 167篇 |
1978年 | 97篇 |
1977年 | 101篇 |
1975年 | 83篇 |
1959年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Jean-Claude Malela-Majika Sandile Charles Shongwe Olatunde Adebayo Adeoti 《Quality and Reliability Engineering International》2021,37(8):3314-3322
The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA scheme. 相似文献
2.
大型综合室内亲子乐园属于高大空间,设有游乐设施和游戏的特殊性使得对空间的舒适性要求一致,但是送风气流遇阻严重,室内存在较多气流死角,影响室内空气质量和儿童健康。因此其空调设计不仅需要考虑温度、风速的空间均匀度,还要考虑各点的空气龄和PMV-PPD指标。以天津某亲子乐园为研究对象,利用scSTREAM软件对适用于该房间的辐射供冷加新风、置换通风、混合通风三种空调方式的送风效果进行数值模拟分析,从流场的均匀性、人员的热舒适性等方面对模拟结果进行探讨,研究结果表明辐射供冷加新风方式的空间均匀性和PMV指标最佳,混合通风方式的空气龄最小。 相似文献
3.
ABSTRACTIn this paper, we review some algebraic control system. Precisely, linear and bilinear systems on Euclidean spaces and invariant and linear systems on Lie groups. The fourth classes of systems have a common issue: to any class, there exists an associated subgroup. From this object, we survey the controllability property. Especially, from those coming from our contribution to the theory. 相似文献
4.
5.
The World robot summit disaster robotics category – achievements of the 2018 preliminary competition
Satoshi Tadokoro Tetsuya Kimura Masayuki Okugawa Katsuji Oogane Hiroki Igarashi Yoshikazu Ohtsubo 《Advanced Robotics》2019,33(17):854-875
The World Robot Summit is a robot Olympics and aims to be held in a different country every four years from 2020. The concept of the Plant Disaster Prevention challenge is daily inspections, checks, and emergency response in industrial plants, and in this competition, robots must carry out these types of missions in a mock-up plant. The concept of the Tunnel Disaster Response and Recovery challenge is emergency response to tunnel disasters, and is a simulation competition whereby teams compete to show their ability to deal with disasters, by collecting information and removing debris. The Standard Disaster Robotics challenge assesses, in the form of a contest, the standard performance levels of a robot that are necessary for disaster prevention and emergency response. The World Robot Summit Preliminary Competition was held at Tokyo Big Sight in October 2018, and 36 teams participated in the Disaster Robotics Category. UGVs and UAVs contended the merits of new technology for solving complex problems, using core technologies such as mobility, sensing, recognition, performing operations, human interface, autonomous intelligence etc., as well as system integration and implementation of strategies for completing missions, gaining high-level results. 相似文献
6.
Temperature history can have a significant effect on the strength of water-saturated chalk.In this study,hydrostatic stress cycles are applied to understand the mechanical response of chalk samples exposed to temperature cycling between each stress cycle,compared to the samples tested at a constant temperature.The total accumulated strain during a stress cycle and the irreversible strain are reported.Chalk samples from Kansas(USA)and Mons(Belgium),with different degrees of induration(i.e.amount of contact cementation),were used.The samples were saturated with equilibrated water(polar)and nonpolar Isopar H oil to quantify water weakening.All samples tested during 10 stress cycles with varying temperature(i.e.temperature cycled in between each stress cycle)accumulated more strain than those tested at constant temperatures.All the stress cycles were performed at 30℃.The two chalk types behaved similarly when saturated with Isopar H oil,but differently when saturated with water.When saturated with water,the stronger Kansas chalk accumulated more total strain and more irreversible strain within each stress cycle than the weaker Mons chalk. 相似文献
7.
In this paper, we study scheduling games under mixed coordination mechanisms on hierarchical machines. The two scheduling policies involved are ‐ and ‐, where ‐ (resp., ‐) policy sequences jobs in nondecreasing order of their hierarchies, and jobs of the same hierarchy in nonincreasing (resp., nondecreasing) order of their processing times. We first show the existence of a Nash equilibrium. Then we present the price of anarchy and the price of stability for the games with social costs of minimizing the makespan and maximizing the minimum machine load. All the bounds given in this paper are tight. 相似文献
8.
介绍一种基于变频调速控制的全自动定量包装机,结构简单,组态灵活,性价比高,可广泛应用于食品饲料等行业,现场运行实践证明其通用性好,准确度和可靠性高、速度快、稳定性好。并论述变频器控制系统的设计及使用中的注意问题。 相似文献
9.
10.