全文获取类型
收费全文 | 608篇 |
免费 | 12篇 |
专业分类
电工技术 | 16篇 |
化学工业 | 72篇 |
金属工艺 | 6篇 |
机械仪表 | 8篇 |
建筑科学 | 19篇 |
矿业工程 | 1篇 |
能源动力 | 28篇 |
轻工业 | 48篇 |
水利工程 | 2篇 |
无线电 | 27篇 |
一般工业技术 | 67篇 |
冶金工业 | 259篇 |
原子能技术 | 2篇 |
自动化技术 | 65篇 |
出版年
2024年 | 3篇 |
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 21篇 |
2013年 | 32篇 |
2012年 | 14篇 |
2011年 | 31篇 |
2010年 | 19篇 |
2009年 | 19篇 |
2008年 | 30篇 |
2007年 | 20篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 12篇 |
2001年 | 25篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 7篇 |
1996年 | 19篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 7篇 |
1992年 | 15篇 |
1991年 | 4篇 |
1990年 | 15篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1975年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有620条查询结果,搜索用时 46 毫秒
101.
Scientometrics - Open Access has emerged as an important movement worldwide during the last decade. There are several initiatives now that persuade researchers to publish in open access journals... 相似文献
102.
Das Swarup Chattopadhyay Krishnendu Bhadra Chaudhuri Sekhar Ranjan 《Wireless Personal Communications》2020,110(2):677-698
Wireless Personal Communications - In this paper a combination of rectangular and elliptical fractal geometry is applied on a regular hexagonal wide slot antenna fabricated using a FR4 substrate to... 相似文献
103.
Roy Swarup Ezati Parya Rhim Jong-Whan Molaei Rahim 《Journal of Materials Science》2022,57(4):2941-2952
Journal of Materials Science - The work describes the preparation of carbon dots using turmeric as the carbon source and their functionalization with sulfur to enhance the functionality. The... 相似文献
104.
Yogi Priyanka Poonia Deepika Yadav Pooja Mishra Suryakant Saxena Shailendra K. Roy Swarup Sagdeo Pankaj R. Kumar Rajesh 《SILICON》2018,10(6):2801-2807
Silicon - Nano-metal/semiconductor junction dependent porosification of silicon has been studied here. The silicon nanostructures (SiNSs) have been textured on n- and p- type silicon wafers using... 相似文献
105.
Biologically produced mucic acid may form crystals before being separated from the biomass. Here we use Soxhlet extraction of fungal biomass to obtain mucic acid that was otherwise lost when separating biomass from the supernatant. Culture supernatant was used to extract the biomass, avoiding dilution of the mucic acid while retaining a cell-free suspension. Soxhlet extraction of biomass recovered 7% of total mucic acid produced at pH 4 and 24% at pH 6. The potential for mucic acid to cyclize to the 1,4-lactone was investigated by solid state NMR, confirming that very little lactone was present after the crystallization step. 相似文献
106.
107.
As federal dollars available for highway projects are tightened and as demand for more highway capacity continues to increase, transportation officials seek more innovative financing methods. One of the more common methods has been to toll new highway projects. Recently, tollways also have been considered for existing, free-access roadways, i.e., nontolled, infrastructure segments. Transportation planners must consider that this so-called “innovative” financing technique, i.e., the decision to toll existing and new roadways, is subject to provisions of the National Environmental Protection Act (NEPA). This renewed interest in tolling mandates that transportation planners revisit the requirements of NEPA, and in this context, its applicability to decisions to toll roads for financing of highway projects. NEPA requires that, prior to construction of a bridge or highway, the head of the federal agency that is committing funds to the project must evaluate the effect of the project on the human environment; the effect of the project on the habitat of an endangered species, which implicates provisions of the Endangered Species Act; the effect of the project on any historic properties in the vicinity of the project, which implicates provisions of the National Historic Preservation Act, and the effect of the project on minority or low-income-populations, called environmental justice, which implicates Title VI of the Civil Rights Act of 1964. In this paper, we analyze the requirements of NEPA as they relate to Title VI of the Civil Rights Act of 1964. The interrelation of the two acts now mandates that the transportation planner consider an environmental justice concept in planning for highway and bridge projects. The intent of this paper is to provide some guidance to transportation planners in light of the environmental justice issues implicated by Title VI of the Civil Rights Act of 1964 as they begin the planning stages for highway and bridge projects. 相似文献
108.
A phenyl ether phenyl phosphate polymer, specifically poly(biphenyl ether triphenyl phosphate), was modified to increase its tractability and to improve its toughness. The first goal was achieved by increasing its solubility by sulfonation of the chain, and the second, by the in situ generation of a rubbery phase. This phase was generated by a modification of the usual sol–gel reaction (which usually generates a hard silicalike material by the hydrolysis of a tetrafunctional organosilicate). In this case, a difunctional silicate was included, thus introducing some softening organic groups into the dispersed phase. A bonding agent, N,N‐diethylaminopropyltrimethoxysilane, was also included to improve the bonding between the two phases in this organic–inorganic composite. As expected, the glass transition temperatures generally increased slightly upon sulfonation, but decreased significantly upon introduction of the rubbery phase. Most important, the toughness of the polymer was successfully increased with, for example, only 8 wt % of the rubbery phase, quadrupling extensibility to 20 % and markedly increasing the toughness. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2326–2330, 2001 相似文献
109.
Zinian Wang Marilyn L. Kwan Reina Haque Prashant K. Singh Maciej Goniewicz Rachel Pratt Valerie S. Lee Janise M. Roh Isaac J. Ergas Kimberly L. Cannavale Ronald K. Loo David S. Aaronson Charles P. Quesenberry Yuesheng Zhang Christine B. Ambrosone Lawrence H. Kushi Li Tang 《Molecular nutrition & food research》2024,68(8):2400087
110.
The first-order algorithm is an algorithm for recovering the motion parameters from a single optical flow field. It compares the spatial derivatives, to first order, of the optical flow field obtained from two different parts of the field of view and obtains a linear constraint on the direction of the translational velocity. We modify this algorithm to incorporate the spatial derivatives, to first order, of the optical flow field obtained from a third part of the field of view, and thereby obtain two further linear constraints on the direction of the translational velocity. Only two linear constraints are required to identify the direction of the translational velocity. Therefore, with three linear constraints, there are three ways of estimating the direction of the translational velocity. Although all three estimates are derived from the same set of information, we show that the three estimates are not, in general, equally stable. We assume that each cluster of flow vectors arises from a plane in the environment and show that a linear constraint is most stable when it emanates from a pair of parallel planes, with the camera between them. We also identify the relative orientations of the clusters of flow vectors that maximize and minimize the stability of the linear constraint that they give rise to. © 1996 John Wiley & Sons, Inc. 相似文献