全文获取类型
收费全文 | 415篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 56篇 |
金属工艺 | 3篇 |
机械仪表 | 11篇 |
建筑科学 | 16篇 |
矿业工程 | 3篇 |
能源动力 | 17篇 |
轻工业 | 19篇 |
水利工程 | 13篇 |
石油天然气 | 2篇 |
无线电 | 61篇 |
一般工业技术 | 62篇 |
冶金工业 | 40篇 |
原子能技术 | 3篇 |
自动化技术 | 110篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 1篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 23篇 |
2012年 | 20篇 |
2011年 | 26篇 |
2010年 | 22篇 |
2009年 | 34篇 |
2008年 | 34篇 |
2007年 | 27篇 |
2006年 | 30篇 |
2005年 | 26篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 15篇 |
1999年 | 9篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有422条查询结果,搜索用时 0 毫秒
121.
122.
123.
124.
Edmond H.P. van Hees Edith I.B. Chopin Talia M. Sebastian Gibran D. Washington LeAnn M. Germer Patricia Domanski Doug Martz Linda Schweitzer 《Journal of Great Lakes research》2010
The Clinton River watershed near Detroit, Michigan, USA was separated in six different land uses: agricultural, residential, mixed industrial and residential, downstream industrial, Clinton River Spillway, and Lake St. Clair, utilizing As, Cd, Cu, Ni, Pb, and Zn contents of the sediment that has median values of 3, 0.3, 15, 14, 13, and 57 mg kg− 1, respectively. However, trace element concentrations in the lower Clinton River rivaled those in the most contaminated watersheds of the world. Enrichment factors and principal component analysis (PCA) separated trace elements into 2 categories: anthropogenic (Cd, Cu, Ni, Pb, and Zn) and geogenic (Al, As, Ca, Fe, K, Mg, TOC) sources. PCA linked agricultural, residential, and mixed industrial and residential land uses to anthropogenic Cd, Cu, Ni, Pb, and Zn, and lake sediments to geogenic elements, organic matter and clay contents. The downstream industrial zone has a unique source signature. Trace element concentrations varied with land use. The upper Clinton River (> 20 km from mouth; residential land use; median concentrations up to 25 mg kg− 1) appeared to meet delisting criteria. Partitioning was also land use and element specific with: (1) exchangeable fraction (up to 94% of total) related to road salt and mobile chloride complex formation; (2) carbonate-bound fraction (up to 100%) resulting from Ca substitution or adsorption; (3) presence of immobile (hydr)oxide-bound fraction (up to 90%) instead of potentially mobile organic matter and sulphide-bound fraction (up to 20%); and (4) residual fraction (up to 65%) originating from geogenic and/or anthropogenic sources. 相似文献
125.
Valerie C. Moore Laura A. McJilton Sean T. Pheasant Carter Kittrell Robin E. Anderson Doug Ogrin Feng Liang Robert H. Hauge Howard K. Schmidt James M. Tour W. Edward Billups Andrew R. Barron Richard E. Smalley 《Carbon》2010,48(2):561-565
The present study demonstrates the viability of the reductive attachment step of the single walled carbon nanotube (SWCNT) lengthening process in which long SWCNTs are grown from short nanotube seeds. Aryl sulfonate sidewall-functionalized, carboxylate end-functionalized SWCNTs are attached to an inorganic cluster pro-catalyst (FeMoC) via ligand exchange. The SWCNT-FeMoC complex was electrodeposited onto highly ordered pyrolytic graphite (HOPG), heated and exposed to etching conditions. Pre- and post-treatment AFM imaging shows that controlled reductive etching of the SWCNTs is attainable at a variety of pressures and temperatures in hot surface/cold gas and hot surface/hot gas systems. 相似文献
126.
127.
We deal with a resource allocation problem for multimedia service discrimination in wireless networks. We assume that a service provider allocates network resources to users who can choose and access one of the discriminated services. To express the rational service selection of users, the utility function of users is devised to reflect both service quality and cost. Regarding the utility function of a service provider, total profit and efficiency of resource usage have been considered. The proposed service discrimination framework is composed of two game models. An outer model is a repeated Stackelberg game between a service provider and a user group, while an inner model is a service selection game among users, which is solved by adopting the Kalai‐Smorodinsky bargaining solution. Through simulation experiments, we compare the proposed framework with existing resource allocation methods according to user cost sensitivity. The proposed framework performed better than existing frameworks in terms of total profit and fairness. 相似文献
128.
129.
A robust cell voltage monitoring system for analysis and diagnosis of fuel cell or battery systems 总被引:1,自引:0,他引:1
Cell voltage monitoring (CVM) systems are essential for the operation of fuel cell stacks and some battery systems, in the field as well as in the laboratory, because they allow the diagnosis and correction of problems that would otherwise go unnoticed and cause impaired performance or even permanent damage. A robust, safe, and low-cost design for a CVM unit is presented, using electromechanical relays as multiplexing switches. Some examples from the application of the unit on the University of Delaware's fuel cell battery hybrid buses are presented, including its use in automatically correcting anode flooding and diagnosing air channel blockage. 相似文献
130.
Regis Kopper Doug A. Bowman Mara G. Silva Ryan P. McMahan 《International journal of human-computer studies》2010,68(10):603-615
Models of human motor behavior are well known as an aid in the design of user interfaces (UIs). Most current models apply primarily to desktop interaction, but with the development of non-desktop UIs, new types of motor behaviors need to be modeled. Distal pointing—pointing directly at a target that is remotely situated with respect to the input device—is such a motor behavior. A model of distal pointing would be particularly useful in the comparison of different interaction techniques, because the performance of such techniques is highly dependent on user strategy, making controlled studies difficult to perform. Inspired by Fitts’ law, we studied four possible models and concluded that movement time for a distal pointing task is best described as a function of the angular amplitude of movement and the angular size of the target. Contrary to Fitts’ law, our model shows that the angular size has a much larger effect on movement time than the angular amplitude and that the growth in the difficulty of the tasks is quadratic, rather than linear. We estimated the model's parameters experimentally with a correlation coefficient of 96%. 相似文献