全文获取类型
收费全文 | 1816篇 |
免费 | 105篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 38篇 |
综合类 | 6篇 |
化学工业 | 512篇 |
金属工艺 | 51篇 |
机械仪表 | 78篇 |
建筑科学 | 65篇 |
矿业工程 | 7篇 |
能源动力 | 124篇 |
轻工业 | 176篇 |
水利工程 | 6篇 |
石油天然气 | 45篇 |
无线电 | 167篇 |
一般工业技术 | 342篇 |
冶金工业 | 68篇 |
原子能技术 | 24篇 |
自动化技术 | 230篇 |
出版年
2024年 | 4篇 |
2023年 | 30篇 |
2022年 | 51篇 |
2021年 | 95篇 |
2020年 | 94篇 |
2019年 | 120篇 |
2018年 | 120篇 |
2017年 | 108篇 |
2016年 | 92篇 |
2015年 | 56篇 |
2014年 | 112篇 |
2013年 | 194篇 |
2012年 | 121篇 |
2011年 | 159篇 |
2010年 | 120篇 |
2009年 | 80篇 |
2008年 | 66篇 |
2007年 | 57篇 |
2006年 | 33篇 |
2005年 | 19篇 |
2004年 | 18篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 12篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1939条查询结果,搜索用时 328 毫秒
91.
92.
Farid Miloua Amar Tilmatine Sidi-Mohammed Remaoun Djeloul Berrached Malika Bengrit 《The International journal of environmental studies》2013,70(4):527-535
The paper reports the development and implementation of a cost-effective electrostatic precipitator (ESP) prototype for the medical wastes incinerator of university hospital centre (CHU) of Sidi-Bel-Abbes, using a water washing system for cleaning electrodes. The impact of medical waste incineration on human health is a topical debate. The incineration process is a safe mode of disposal [OK] of such waste, but it is not an effective solution and needs a pollution control system. Generally, in Africa, cost is the major constraint for manufacturers and users. A half-scale ESP model was initially used for an experimental study in the laboratory. Thereafter, a full-scale model was produced and installed for the incinerator based on the optimal values obtained from this preliminary study. 相似文献
93.
Gaoming Zhu Xiaohong Wang Peizhong Feng Zhangsheng Liu Jinan Niu Farid Akhtar 《Journal of the American Ceramic Society》2016,99(4):1147-1150
MoB and SiC particulate reinforced MoSi2 matrix composites were synthesized in situ from Mo, Si, and B4C powder mixtures by self‐propagating high‐temperature synthesis (SHS). The SHS MoSi2–MoB–SiC products were vacuum hot‐pressed (HPed) at 1400°C for 90 min to fabricate high‐density (> 97.5% relative density) bulk composites. Microstructure refinement and improvements in the Vickers hardness and fracture toughness of the HPed composites were observed with increasing B4C content in the reaction mixture. The HPed composite of composition MoSi2–0.4MoB–0.1SiC exhibited grain size of 1–5 μm, Vickers hardness of 12.5 GPa, bending strength of 537 MPa, and fracture toughness of 3.8 MPa.m1/2. These excellent mechanical properties indicate that MoB and SiC particulate reinforced MoSi2 composites could be promising candidates for structural applications. 相似文献
94.
Elaheh Abdollahi Mehdi Salami-Kalajahi Ali Mohammadi Ali Khalafi-Nezhad 《Designed Monomers and Polymers》2016,19(1):56-66
Diethyl-dithiocarbamic acid 2-[4-(2-diethylthiocarbamoylsulfanyl-2-phenyl-acetyl)-2,5-dioxo-piperazin-1-yl]-2-oxo-1-phenyl-ethyl ester as a novel di-functional reversible addition–fragmentation chain transfer (RAFT) agent was synthesized based on 2,5-diketopiperazine. The RAFT agent was designed based on the propagating core (R group) approach and characterized by 1H NMR, 13C NMR, FT-IR, elemental analysis, and melting point technique. Then, ethyl methacrylate was synthesized via free radical and RAFT polymerizations. To investigate the effect of the RAFT agent on the kinetic of polymerization, molecular weight, and polydispersity index (PDI) of polymers and also monomer conversion were monitored. Also, synthesized polymers were characterized by 1H NMR, 13C NMR, FT-IR, and TGA. Characterization analyses of synthesized RAFT agent were consistent with the structure. NMR and FTIR analyses confirmed end group incorporation of RAFT agent into polymer structure. According to results, poly(ethyl methacrylate) with low PDI (1.14) was obtained. Kinetic study indicated well-controlled polymerization of ethyl methacrylate by synthesized RAFT agent. TGA results showed that RAFT agent could reduce termination reactions and so reduce head-to-head bonds and chain-end unsaturation by keeping the concentration of radicals low enough. 相似文献
95.
Nema Ankita Bano Mustri Rai Mansi Shrivastava Kavya Dangi Sambhavna Singh Khan Farid 《Journal of Porous Materials》2022,29(2):459-471
Journal of Porous Materials - Silver monoliths using non-ionic surfactant Triton X-102 as reducing agent with and without additives such as Dextran and Ludox (SiNPs) were synthesized by modified... 相似文献
96.
Hassan Elmkhah Mohammad-Rashed Mohammadi Maryam Molaei Ashkan Zolriasatein Mostafa Meghdari Arash Fattah-alhosseini 《International Journal of Applied Ceramic Technology》2022,19(6):3072-3083
This study aims to investigate how the predeposition machining processes such as magnetic grinding, turning machining, and wire electrical discharge machining can influence the surface properties including electrochemical and tribological behavior of TiCrN nanostructured coating applied on Mo40 steel substrate. A physical vapor deposition technique using cathodic arc evaporation was used to apply the coating. The crystallographic phases and the microstructure of the coating were studied by X-ray diffraction and scanning electron microscope, respectively. Rockwell-C, electrochemical impedance spectroscopy and potentiodynamic polarization, and pin-on-disk wear tests were employed to evaluate the adhesion strength, corrosion behavior, and tribological property of specimens, respectively. The electrochemical results after 24 h of exposure to 3.5 wt% NaCl solution showed that TiCrN coating pretreated with a turning process with polarization resistance of about 3525.32 Ω.cm2 had the best corrosion resistance among all specimens. This was because of the improvement of the smoothness, surface quality, and adhesion after the turning process. On the other, the friction coefficient of the grounded sample is less than that of other ones. This is probably due to its higher adhesion strength and higher surface smoothness. 相似文献
97.
Ternary gas permeation through synthesized pdms membranes: Experimental and CFD simulation basedon sorption‐dependent system using neural network model
下载免费PDF全文
![点击此处可从《Polymer Engineering and Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ehsan Farno Mashallah Rezakazemi Toraj Mohammadi Norollah Kasiri 《Polymer Engineering and Science》2014,54(1):215-226
In this study, a predictive model for the separation of gases via a polydimethylsiloxane (PDMS) membrane has been developed. This model takes into account the effects of gas composition and pressure at the membrane surfaces on the gas sorption and diffusion coefficients in the membrane. Computational fluid dynamics (CFD) modeling has been employed in order to predict the behavior of a gas mixture containing C3H8, CH4, and H2 at various operating conditions and three zones (upstream, downstream, and membrane body). Artificial neural network (ANN) modeling has been applied to predict sorption and diffusion coefficients of each component of the gas mixture in the membrane. A procedure of calculation has been applied to combine the CFD modeling and the ANN modeling in order to predict sorption, diffusion, and composition of each component at various sites of the membrane. The results determined using the developed prediction model have been found to be in agreement with those determined using experimental investigations with an average error of 10.21%. POLYM. ENG. SCI., 54:215–226, 2014. © 2013 Society of Plastics Engineers 相似文献
98.
Adil Farooq Arfa Iqbal Nosheen Fatima Rana Misha Fatima Tuba Maryam Farhat Batool Zahra Rehman Farid Menaa Shabia Azhar Afrah Nawaz Faheem Amin Zuhair M. Mohammedsaleh Salma Saleh Alrdahe 《International journal of molecular sciences》2022,23(6)
Chronic liver disease (CLD) is a global threat to the human population, with manifestations resulting from alcohol-related liver disease (ALD) and non-alcohol fatty liver disease (NAFLD). NAFLD, if not treated, may progress to non-alcoholic steatohepatitis (NASH). Furthermore, inflammation leads to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Vitexin, a natural flavonoid, has been recently reported for inhibiting NAFLD. It is a lipogenesis inhibitor and activates lipolysis and fatty acid oxidation. In addition, owing to its antioxidant properties, it appeared as a hepatoprotective candidate. However, it exhibits low bioavailability and low efficacy due to its hydrophobic nature. A novel rat model for liver cirrhosis was developed by CCL4/Urethane co-administration. Vitexin encapsulated liposomes were synthesized by the ‘thin-film hydration’ method. Polyethylene glycol (PEG) was coated on liposomes to enhance stability and stealth effect. The diseased rats were then treated with vitexin and PEGylated vitexin liposomes, administered intravenously and orally. Results ascertained the liposomal encapsulation of vitexin and subsequent PEG coating to be a substantial strategy for treating liver cirrhosis through oral drug delivery. 相似文献
99.
Study of the sensitivity and resonant frequency of the torsional modes of an AFM cantilever with a sidewall probe based on a nonlocal elasticity theory
下载免费PDF全文
![点击此处可从《Microscopy research and technique》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A relationship based on a nonlocal elasticity theory is developed to investigate the torsional sensitivity and resonant frequency of an atomic force microscope (AFM) with assembled cantilever probe (ACP). This ACP comprises a horizontal cantilever and a vertical extension, and a tip located at the free end of the extension, which makes the AFM capable of topography at sidewalls of microstructures. First, the governing differential equations of motion and boundary conditions for dynamic analysis are obtained by a combination of the basic equations of nonlocal elasticity theory and Hamilton's principle. Afterward, a closed‐form expression for the sensitivity of vibration modes has been obtained using the relationship between the resonant frequency and contact stiffness of cantilever and sample. These analysis accounts for a better representation of the torsional behavior of an AFM with sidewall probe where the small‐scale effect are significant. The results of the proposed model are compared with those of classical beam theory. The results show that the sensitivities and resonant frequencies of ACP predicted by the nonlocal elasticity theory are smaller than those obtained by the classical beam theory. Microsc. Res. Tech. 78:408–415, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
100.
Influence of seismicity level and height of the building on progressive collapse resistance of steel frames
下载免费PDF全文
![点击此处可从《The Structural Design of Tall and Special Buildings》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Influences of building height and seismicity level on progressive collapse resistance of buildings are investigated in this paper. For the height, 4‐story, 8‐story and 12‐story steel special moment resisting frames are focused. The obtained results indicate that taller buildings are safer against progressive collapse. To study the influence of seismicity level, different four‐story structures having special moment resisting frame systems are designed for different levels of seismicity, namely, very high, high, moderate and low. The structures are evaluated, using nonlinear dynamic method and two main scenarios of the codes, including sudden removal of a corner and a middle column in the first floor. Some graphs are presented for progressive collapse resistance of the structures, depending on their seismic base shears. It is shown that the structures designed for greater seismic base shears are more resistant against progressive collapse. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献