全文获取类型
收费全文 | 2016篇 |
免费 | 87篇 |
国内免费 | 43篇 |
专业分类
电工技术 | 72篇 |
综合类 | 77篇 |
化学工业 | 536篇 |
金属工艺 | 67篇 |
机械仪表 | 137篇 |
建筑科学 | 90篇 |
矿业工程 | 24篇 |
能源动力 | 154篇 |
轻工业 | 184篇 |
水利工程 | 19篇 |
石油天然气 | 99篇 |
武器工业 | 4篇 |
无线电 | 78篇 |
一般工业技术 | 337篇 |
冶金工业 | 83篇 |
原子能技术 | 44篇 |
自动化技术 | 141篇 |
出版年
2023年 | 10篇 |
2022年 | 23篇 |
2021年 | 36篇 |
2020年 | 45篇 |
2019年 | 29篇 |
2018年 | 35篇 |
2017年 | 49篇 |
2016年 | 37篇 |
2015年 | 49篇 |
2014年 | 74篇 |
2013年 | 148篇 |
2012年 | 82篇 |
2011年 | 115篇 |
2010年 | 103篇 |
2009年 | 103篇 |
2008年 | 132篇 |
2007年 | 146篇 |
2006年 | 110篇 |
2005年 | 81篇 |
2004年 | 75篇 |
2003年 | 91篇 |
2002年 | 70篇 |
2001年 | 66篇 |
2000年 | 55篇 |
1999年 | 39篇 |
1998年 | 56篇 |
1997年 | 32篇 |
1996年 | 31篇 |
1995年 | 31篇 |
1994年 | 31篇 |
1993年 | 27篇 |
1992年 | 20篇 |
1991年 | 17篇 |
1990年 | 13篇 |
1989年 | 18篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1974年 | 3篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有2146条查询结果,搜索用时 15 毫秒
1.
Damir Sagdeev Il'giz Gabitov Chingiz Isyanov Vener Khairutdinov Mansur Farakhov Zufar Zaripov Ilmutdin Abdulagatov 《Journal of the American Oil Chemists' Society》2019,96(6):647-662
The densities of oleic acid were measured over the temperature range from (293 to 459) K at atmospheric pressure using a densimeter based on the modified hydrostatic weighing method. The dynamic viscosities of the same oleic acid sample were measured using a capillary viscometer (VPZ-2 m) in the range from (293 to 363) K at atmospheric pressure. The combined expanded uncertainty of the density, atmospheric pressure, viscosity, and temperature measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.15%, 1.0%, 3.5%, and 15 mK, respectively. The values of uncertainty for density and viscosity include the effects of purity and calibration (total expanded uncertainty). These experimental data were used to develop wide-range correlations for the density and viscosity based on theoretically confirmed Arrhenius–Andrade and Vogel-Tamman-Fulcher (VTF) models. The value of the glass temperature ( T g= 179.78 K.) for the oleic acid was estimated using the VTF parameters derived from the present viscosity measurements. To additionally validate the reliability of the measured density data, the same oleic acid samples were measured using the pycnometric method. The present study showed that the densities measured using the modified hydrostatic weighing densimeter (HWD) agree with the values obtained using the pycnometric method within 0.09% for Sample 1 and 0.25% for Sample 2. 相似文献
2.
László Lőrincz Máté Zsemberi György Bánsághi Tamás Sohajda Edit Székely 《化学工程与技术》2018,41(7):1466-1472
Chiral molecules, especially enantiomers and diastereomers of purity > 99 %, present a significant market share within the chemical, pharmaceutical, and flavor industries. Antisolvent precipitations, both batch and semicontinuous operations to serve the current trends in flow chemistry were demonstrated to be environmentally benign and efficient tools in achieving high optical purities. Although salts are known to be insoluble in supercritical CO2, instabilities of the nascent salts were detected and applied for increasing efficiency. Diastereomeric excess values of the crystalline products exceeded 99 % in maximum of three consecutive steps both by repeated resolution with half molar equivalent of the amine to the acid and by direct recrystallization of the salts. 相似文献
3.
David L. Wood Jeffrey D. Quass Jianlin Li Shabbir Ahmed David Ventola Claus Daniel 《Drying Technology》2018,36(2):234-244
Processing lithium-ion battery (LIB) electrode dispersions with water as the solvent during primary drying offers many advantages over N-methylpyrrolidone (NMP). An in-depth analysis of the comparative drying costs of LIB electrodes is discussed for both NMP- and water-based dispersion processing in terms of battery pack $/kWh. Electrode coating manufacturing and capital equipment cost savings are compared for water vs. conventional NMP organic solvent processing. A major finding of this work is that the total electrode manufacturing costs, whether water- or NMP-based, contribute about 8–9% of the total pack cost. However, it was found that up to a 2?×?reduction in electrode processing (drying and solvent recovery) cost can be expected along with a $3–6?M savings in associated plant capital equipment (for a plant producing 100,000 10-kWh Plug-in Hybrid Electric Vehicle (PHEV) batteries) using water as the electrode solvent. This paper shows a different perspective in that the most important benefits of aqueous electrode processing actually revolve around capital equipment savings and environmental stewardship and not processing cost savings. 相似文献
4.
Numerical dissipation acts as artificial viscosity to make smoke viscous. Reducing numerical dissipation is able to recover visual details smeared out by the numerical dissipation. Great efforts have been devoted to suppress the numerical dissipation in smoke simulation in the past few years. In this paper we investigate methods of combating the numerical dissipation. We describe visual consequences of the numerical dissipation and explore sources that introduce the numerical dissipation into course of smoke simulation. Methods are investigated from various aspects including grid variation, high-order advection, sub-grid compensation, invariant conservation, and particle-based improvement, followed by discussion and comparison in terms of visual quality, computational overhead, ease of implementation, adaptivity, and scalability, which leads to their different applicability to various application scenarios. 相似文献
5.
6.
在油气井的试油测试资料中,压力恢复曲线有时会出现下滑现象,常被认为是施工失误所致。本文以实际资料为例,分析了“下滑恢复”的压力响应特征和影响因素,认为只在低渗透地层有可能产生“下滑恢复”现象,并提出了避免“下滑恢复”的施工建议。 相似文献
7.
8.
This paper reports the results of current fundamental research at the Department of Process Engineering, University of Miskolc on the processing of clean coal from Mecsek bituminous coal, Southern Hungary. The theoretical possibility of the separation of different petrographic components was proven experimentally and their liberation degree was determined based on the petrographic composition, flotation kinetic study of isolated components (groups of components), scanning electron microscopy and microprobe analyses. The mill with stirred ball media was chosen for the ultra-fine liberation of the coal components. It was revealed that along with the liberation of coal components, their surface oxidation and spontaneous agglomeration, entrapping the mineral impurities take place in ultra-fine grinding. This paper discusses the interfacial phenomena occurring in the ultra-fine grinding process and their influence on the flotation. The concept for the advanced preparation of clean coal was developed, tested and proved. The main steps of this concept are the ultra-fine liberation in the stirred-media mill, the de-agglomeration of flocs spontaneously formed during the ultra-fine grinding and the induced (hydrophobic) flocculation with the following two-step flotation in a flotation column. 相似文献
9.
This article theoretically investigates the drying of uncoated paper with gas-fired infrared (IR) emitters installed within the drying section of a given commercial paper machine. Specifically, it presents the ideal location of two opposing IR emitters within the drying section. The ideal location of the two opposing IR emitters corresponds to the highest machine speed with specified average moisture content of paper sheet at the end of the drying section. This article also presents the average evaporation rate, temperature, and moisture content of the paper sheet as it travels through the drying section with the two opposing IR emitters operating at the optimum location. In addition, the temperature and moisture profiles in the sheet thickness direction, before and after the IR emitters, are provided. This article is not concerned with the potential effects of drying with IR emitters on paper sheet properties and machine runnability issues. 相似文献
10.
Y. Kraftmakher 《International Journal of Thermophysics》1994,15(5):983-991
Relaxation phenomena due to equilibration of point defects in metals are reviewed. The relaxation effect in specific heat observed in tungsten and platinum confirms that in both cases the nonlinear increase in the high-temperature specific heat has to be attributed to point-defect formation. Relaxation phenomena observed by measurements of electrical resistivity and positron annihilation are also considered. The comparison of the data seems to be favorable for the conclusion that all the phenomena are of one origin. 相似文献