全文获取类型
收费全文 | 2235篇 |
免费 | 157篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 29篇 |
综合类 | 3篇 |
化学工业 | 538篇 |
金属工艺 | 40篇 |
机械仪表 | 65篇 |
建筑科学 | 59篇 |
矿业工程 | 6篇 |
能源动力 | 126篇 |
轻工业 | 247篇 |
水利工程 | 15篇 |
石油天然气 | 47篇 |
无线电 | 244篇 |
一般工业技术 | 431篇 |
冶金工业 | 114篇 |
原子能技术 | 13篇 |
自动化技术 | 423篇 |
出版年
2024年 | 7篇 |
2023年 | 58篇 |
2022年 | 91篇 |
2021年 | 130篇 |
2020年 | 98篇 |
2019年 | 77篇 |
2018年 | 117篇 |
2017年 | 110篇 |
2016年 | 110篇 |
2015年 | 66篇 |
2014年 | 91篇 |
2013年 | 200篇 |
2012年 | 150篇 |
2011年 | 164篇 |
2010年 | 101篇 |
2009年 | 115篇 |
2008年 | 89篇 |
2007年 | 95篇 |
2006年 | 79篇 |
2005年 | 65篇 |
2004年 | 43篇 |
2003年 | 38篇 |
2002年 | 28篇 |
2001年 | 16篇 |
2000年 | 20篇 |
1999年 | 17篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 11篇 |
1993年 | 21篇 |
1992年 | 10篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有2400条查询结果,搜索用时 15 毫秒
101.
102.
Omar Hernández-González Mondher Farza Tomas Ménard Mohammed M'Saad Rogelio Lozano 《International journal of systems science》2019,50(5):1089-1105
This paper proposes a new high gain observer for a class of non-uniformly observable nonlinear systems with coupled structure driven by sampled outputs. The considered class of systems is particularly constituted by several subsystems where each subsystem is associated to a subset of the output variables. The observer design is carried out through two steps. First, a high-gain observer is proposed in the continuous-time output case under the assumption that an adequate persistent excitation condition is satisfied by each subsystem. Then, the proposed observer is redesigned to handle the case of sampled outputs leading thereby to a continuous-discrete time observer. The latter property is achieved thanks to the approach pursued along the convergence analysis. The effectiveness of the proposed observer is emphasised in a realistic simulation framework involving a mathematical model of a quadrotor which is diffeomorphic to the proposed class of considered systems. 相似文献
103.
104.
Magnifying micro-movements of natural videos that are undetectable by human eye has recently received considerable interests, due to its impact in numerous applications. In this paper, we use dual tree complex wavelet transform (DT-CWT), to analyze video frames in order to detect and magnify micro-movements to make them visible. We use DT-CWT, due to its excellent edge-preserving and nearly-shift invariant features. In order to detect any minor change in object’s spatial position, the paper proposes to modify the phases of the CWT coefficients decomposition of successive video frames. Furthermore, the paper applies Radon transform to track frame micro-movements without any temporal band-pass filtering. The paper starts by presenting a simple technique to design orthogonal filters that construct this CWT system. Next, it is shown that modifying the phase differences between the CWT coefficients of arbitrary frame and a reference one results in image spatial magnification. This in turn, makes these micro-movements seen and observable. Several simulation results are given, to show that the proposed technique competes very well to the existing micro-magnification approaches. In fact, as it manages to yield superior video quality in far less computation time. 相似文献
105.
Abdul Khalib Zahereel Ishwar Ehtiba Farij Omar Ahmad R. Badlishah Salim Naseer Sabri Rahman Mostafijur Li Mingfu 《Multimedia Tools and Applications》2018,77(21):28799-28816
Multimedia Tools and Applications - Adaptive Media Playout (AMP) controls adapt playout rate to prevent buffer outage and to reduce delay in playout. Most AMP techniques use buffer fullness or its... 相似文献
106.
The future of iron pnictide superconductors in technology is still undecided. While these materials are now known to possess relatively high critical temperatures and critical magnetic fields, processing methods for these superconductors are still in the development stage. Recently we have been investigating possible ways to speed up the synthetic process for obtaining polycrystalline iron arsenide superconductors and other transition metal pnictides. Here we report the synthesis of NdFeAsO and NdFe0.9Co0.1AsO in less than 1 h total exposure to microwave radiation using an additional microwave susceptor to surround the reaction ampoule. Structure and property measurements reveal the samples to be of high quality and superconducting when Co doped. 相似文献
107.
María Dolores López‐Ramírez Ulises Miguel García‐Ventura Fabricio Omar Barroso‐Muñoz Juan Gabriel Segovia‐Hernández Salvador Hernández 《化学工程与技术》2016,39(2):271-275
The esterification of oleic acid and methanol using sulfuric acid as a homogeneous catalyst is studied in reactive‐separation systems. The conversion of the free fatty acid was investigated in two different experiments with the molar ratio of methanol/oleic acid, amount of catalyst, temperature, and reaction time as variables. The conversion of the free fatty acid was found to depend strongly on the molar ratio of methanol/oleic acid. The reaction time had a direct effect on the conversion of the free fatty acid, and this conversion decreased with higher temperature. These results were valuable for a preliminary study on biodiesel production, using an acid homogeneous catalyst in a reactive dividing‐wall distillation column. 相似文献
108.
109.
Fuzzy frequency response: definition and analysis for uncertain dynamic systems is proposed in this paper. In terms of transfer function, the uncertain dynamic system is partitioned into several linear sub‐models and organized according to Takagi–Sugeno fuzzy representation. The main contribution of this paper is to demonstrate through the proposal of a Theorem that fuzzy frequency response is a boundary in the magnitude and phase Bode plots. Low‐ and high‐frequency analysis of fuzzy dynamic model is obtained by varying the frequency ω from zero to infinity. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
110.
Kuan-Han Lee Wen-Yueh Ho Shu-Jing Wu Hany A. Omar Po-Jui Huang Clay C. C. Wang Jui-Hsiang Hung 《International journal of molecular sciences》2014,15(1):743-757
Despite the advances in cancer therapy and early detection, breast cancer remains a leading cause of cancer-related deaths among females worldwide. The aim of the current study was to investigate the antitumor activity of a novel compound, 4-(3,4,5-trimethoxyphenoxy)benzoic acid (TMPBA) and its mechanism of action, in breast cancer. Results indicated the relatively high sensitivity of human breast cancer cell-7 and MDA-468 cells towards TMPBA with IC50 values of 5.9 and 7.9 μM, respectively compared to hepatocarcinoma cell line Huh-7, hepatocarcinoma cell line HepG2, and cervical cancer cell line Hela cells. Mechanistically, TMPBA induced apoptotic cell death in MCF-7 cells as indicated by 4′,6-diamidino-2-phenylindole (DAPI) nuclear staining, cell cycle analysis and the activation of caspase-3. Western blot analysis revealed the ability of TMPBA to target pathways mediated by mitogen-activated protein (MAP) kinases, 5′ adenosine monophosphate-activated protein kinase (AMPK), and p53, of which the concerted action underlined its antitumor efficacy. In addition, TMPBA induced alteration of cyclin proteins’ expression and consequently modulated the cell cycle. Taken together, the current study underscores evidence that TMPBA induces apoptosis in breast cancer cells via the modulation of cyclins and p53 expression as well as the modulation of AMPK and mitogen-activated protein kinases (MAPK) signaling. These findings support TMPBA’s clinical promise as a potential candidate for breast cancer therapy. 相似文献