全文获取类型
收费全文 | 14118篇 |
免费 | 870篇 |
国内免费 | 117篇 |
专业分类
电工技术 | 209篇 |
综合类 | 62篇 |
化学工业 | 3658篇 |
金属工艺 | 356篇 |
机械仪表 | 500篇 |
建筑科学 | 540篇 |
矿业工程 | 22篇 |
能源动力 | 1001篇 |
轻工业 | 1310篇 |
水利工程 | 198篇 |
石油天然气 | 226篇 |
武器工业 | 4篇 |
无线电 | 1413篇 |
一般工业技术 | 2618篇 |
冶金工业 | 530篇 |
原子能技术 | 96篇 |
自动化技术 | 2362篇 |
出版年
2024年 | 72篇 |
2023年 | 272篇 |
2022年 | 609篇 |
2021年 | 930篇 |
2020年 | 773篇 |
2019年 | 838篇 |
2018年 | 942篇 |
2017年 | 864篇 |
2016年 | 822篇 |
2015年 | 483篇 |
2014年 | 768篇 |
2013年 | 1408篇 |
2012年 | 932篇 |
2011年 | 988篇 |
2010年 | 681篇 |
2009年 | 611篇 |
2008年 | 438篇 |
2007年 | 362篇 |
2006年 | 313篇 |
2005年 | 203篇 |
2004年 | 185篇 |
2003年 | 165篇 |
2002年 | 120篇 |
2001年 | 91篇 |
2000年 | 90篇 |
1999年 | 81篇 |
1998年 | 149篇 |
1997年 | 120篇 |
1996年 | 98篇 |
1995年 | 70篇 |
1994年 | 57篇 |
1993年 | 62篇 |
1992年 | 51篇 |
1991年 | 39篇 |
1990年 | 40篇 |
1989年 | 34篇 |
1988年 | 25篇 |
1987年 | 24篇 |
1986年 | 34篇 |
1985年 | 27篇 |
1984年 | 28篇 |
1983年 | 26篇 |
1982年 | 21篇 |
1981年 | 19篇 |
1980年 | 19篇 |
1979年 | 16篇 |
1978年 | 18篇 |
1977年 | 18篇 |
1976年 | 24篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Threshold cryptography based on Asmuth-Bloom secret sharing 总被引:1,自引:0,他引:1
In this paper, we investigate how threshold cryptography can be conducted with the Asmuth-Bloom secret sharing scheme and present three novel function sharing schemes for RSA, ElGamal and Paillier cryptosystems. To the best of our knowledge, these are the first provably secure threshold cryptosystems realized using the Asmuth-Bloom secret sharing. Proposed schemes are comparable in performance to earlier proposals in threshold cryptography. 相似文献
13.
Engineers of the concrete technology are increasingly concerned with the material passing through a sieve of the size under 0.149 mm. Materials called very fine aggregate or mineral filler may affect the performance of concrete in an either positive or a negative way. Discussions on aggregate containing very fine material are vitally important. Washing the aggregate residue has been the sole way to solve this matter to date. This is mainly based on the debatable opinion that materials of this kind are regarded as clay material. The goal of the study was to determine how the content of mineral filler might affect properties of concrete. Two types of aggregates with different amounts of cement and mineral filler were used. Basically, mineral filler replaced sand. The effect of applying different amounts of mineral filler on concrete was then determined. The addition of 7-10% of mineral filler to fine aggregate (0-2 mm) was found to considerably improve the properties of concrete. 相似文献
14.
Ali M. El-Nashar 《Desalination》1977,20(1-3):267-277
The wastewater from the textile dyeing operations was separated into a concentrate stream, rich in salts and dyes, and a purified product water stream using reverse osmosis membranes. Three membrane materials and three module configurations were used, namely : polyamide (hollow fine fiber configuration ), cellulose acetate ( spiral wound and tubular configurations ) and hydrous Zr(IV)- polyacrylate ( tubular configuration ). The modules were tested for periods ranging from 600 hours to more than 1000 hours under actual field conditions. Membrane flux and rejection were monitored throughout the operation and samples of the feed and product water were analysed chemically. The successful operation of the R.O. equipment under field conditions demonstrated the applicability of this process in the desalination of dyeing wastewater. 相似文献
15.
The compulsion to use bioplastics has increased significantly today. One of the important aspects of plastics is their recyclability. Therefore, the important question of this research is that although bio-based compounds containing starch are sensitive to thermal-mechanical recycling processes, are such products thermally recyclable? To answer the question, polypropylene (PP)/thermoplastic starch (TPS) compound granules were extruded up to five times, and in the other part, single-extruded granules were blended at different ratios with virgin granules by extrusion. In order to characterize these samples, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, rotational disc rheometry, tensile properties, and appearance evaluation were used. The results showed that it is possible to recycle PP/TPS granules up to four times repetition of the extrusion operation and the fifth repetition also showed slight changes. There was also a blend of single-extruded granules with virgin material up to a 50:50% composition without significant variation. 相似文献
16.
Ali Madady 《International Journal of Control, Automation and Systems》2013,11(3):470-481
This paper presents a new iterative learning control (ILC) for discrete-time single-input single-output (SISO) linear time-invariant (LTI) systems. To establish this ILC, the input of the controlled system is modified by using a novel four-parametric algorithm. This algorithm is called the extended proportional plus integral and derivative (EPID) type, since by eliminating the fourth parameter of it one would get to the PID type ILC, therefore PID type ILC is a special case of it. The convergence of the proposed ILC is analyzed and an optimal method is presented to determine its parameters. It is shown that the given ILC has a better performance than the PID-type one. Three illustrative examples are included to demonstrate the effectiveness and the preference of the presented ILC. 相似文献
17.
18.
Automatic onset detection and picking algorithm has been proposed by applying the spectro-ratio on time–frequency sub-band. The proposed algorithm does not need any parameter settings as it will work on data generated by either short or very broad band seismometers. Our algorithm is applied on local events from Cairo region recorded by three stations of the Egyptian National Seismic Network (ENSN). Maximum standard deviation is observed to be 0.113 s of the corresponding manual picks made by analysts. 相似文献
19.
Ahmadi Kourosh Dadashtabar Rashidi Ali Jabar Moghri Ali Massomi 《The Journal of supercomputing》2022,78(15):17309-17347
The Journal of Supercomputing - On the battlefield, early detection of armored vehicles can have a positive effect. Because according to this issue, timely and appropriate reactions can be done.... 相似文献
20.