全文获取类型
收费全文 | 514篇 |
免费 | 58篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 8篇 |
综合类 | 3篇 |
化学工业 | 185篇 |
金属工艺 | 9篇 |
机械仪表 | 18篇 |
建筑科学 | 13篇 |
矿业工程 | 1篇 |
能源动力 | 51篇 |
轻工业 | 77篇 |
水利工程 | 5篇 |
石油天然气 | 12篇 |
无线电 | 35篇 |
一般工业技术 | 66篇 |
冶金工业 | 9篇 |
原子能技术 | 25篇 |
自动化技术 | 60篇 |
出版年
2024年 | 3篇 |
2023年 | 4篇 |
2022年 | 21篇 |
2021年 | 29篇 |
2020年 | 34篇 |
2019年 | 54篇 |
2018年 | 66篇 |
2017年 | 59篇 |
2016年 | 38篇 |
2015年 | 22篇 |
2014年 | 36篇 |
2013年 | 45篇 |
2012年 | 27篇 |
2011年 | 33篇 |
2010年 | 30篇 |
2009年 | 23篇 |
2008年 | 12篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有577条查询结果,搜索用时 218 毫秒
41.
Study of effect of old corrugated cardboard in properties of polypropylene composites: Study of mechanical properties,thermal behavior,and morphological properties 下载免费PDF全文
Nacera Chibani Hocine Djidjelli Alain Dufresne Amar Boukerrou Samira Nedjma 《乙烯基与添加剂工艺杂志》2016,22(3):231-238
The investigation of the economical use of lignocellulose waste, which is one of the environmental problems facing nations, is ongoing. In this study, waste cardboard paper fiber reinforcing polypropylene (PP) composites was developed. In order to modify the PP matrix maleated PP (MA‐g‐PP) a 5 wt% and a grafting rate of 1 and 2 wt% was used as a compatibilizer. The effects of fiber and compatibilizer content as well as graft content are evaluated by mechanical, thermal property measurements, and scanning electron microscopy (SEM). The compatibilizer improved all mechanical properties significantly. Thus, the tensile strength of MA‐g‐PP‐containing composites increases compared to PP/cardboard composites paper content increases. However, the tensile modulus of a PP‐based composite increases with an increase in paper fiber with the compatibilizer having little effect. SEM revealed that the addition of MA‐g‐PP generates strong interactions between a PP matrix and paper fibers. However, the addition of the MA‐g‐PP compatibilizing agent gives a significant improvement on the crystallization of the composites, whereas the compatibilized PP/old corrugated cardboard (OCC) composites have higher crystallinity (Xc) than uncompatibilized PP/OCC composites. The MA‐g‐PP also diminished the water absorption in the composites. J. VINYL ADDIT. TECHNOL., 22:231–238, 2016. © 2014 Society of Plastics Engineers 相似文献
42.
Somayeh Kazemzadeh Zarrindokht Emami-Karvani Nafiseh Sadat Naghavi Giti Emtiazi 《Journal of surfactants and detergents》2022,25(4):439-454
Biosurfactants are produced by important types of microorganisms such as bacteria, yeast, and filamentous fungi and have been used in a variety of industries. Among the 15 crude oil-degrading fungi, the two molds and one yeast were identified by 18S rDNA sequences as Mucor circinelloides strain SKMC, Fusarium fujikuroi strain DB2, and Rhodotorula mucilaginosa strain SKF2. These strains were isolated from crude oil–contaminated soil, diesel oil–contaminated soil, and activated sludge in the Oil Refinery Plant in Isfahan, Iran, respectively. The yeast strain was identified as a novel crude oil–degrading and biosurfactant-producing fungi in the presence of (1% v/v) Iranian light crude oil in the minimal salt medium (MSM). The highest amount of the dry weight of produced biosurfactant was measured at 6.2 g L−1. Chemical nature of produced biosurfactant was determined as a surface-active sophorolipid biosurfactant compound by thin-layer chromatography, Fourier transform infra-red spectroscopy, and gas chromatography–mass spectrometry (GC–MS) analysis. The residual hydrocarbons in the MSM were analyzed by GC–MS, and it was shown that octadecane and docosane were eliminated by this novel strain completely. 相似文献
43.
Seyed Hossein Razavi Hajiagha Hannan Amoozad Mahdiraji Shide Sadat Hashemi 《The International Journal of Advanced Manufacturing Technology》2014,71(1-4):117-126
The purpose of this paper is to develop current mathematical models of cost, time, and quality tradeoffs in conditions that parameters of project activities are estimated uncertainly by grey numbers. In some projects like construction projects, activities can be done within a much shorter time by increasing in the resources, while project's cost may rise at the same time. In such situations, managers are usually required to determine the best combination of cost, time, and quality parameters of the activities, although their information regarding these parameters is limited and rather incomplete. The greyness of these parameters in the proposed method can aid managers to deal with these conditions. The most important aspect of the proposed model is that it considers uncertainty of the project planning data in the form of grey numbers. A combination of fuzzy goal programming and grey linear programming is also developed to solve the proposed model. Finally, this model will provide the managers with a stronger ability to face with uncertainty in project management and planning. The application of this model is examined in a numerical example. As its major finding, the model determines an optimal range in which the project managers can respond to intrinsic changes that may occur in the parameters during a project. 相似文献
44.
Hajimahmoodi Mannan Khanavi Mahnaz Sadeghpour Omid Ardekani Mohammad Reza Shams Mazde Fatemeh Zamani Khoddami Mina Sadat Afzalifard Sheida Ranjbar Ali Mohammad 《Food Analytical Methods》2016,9(12):3451-3459
Food Analytical Methods - Vinegar as a nutraceutical substance is classified to various types related to the different substances applied in production process. Therefore, identity of the source... 相似文献
45.
46.
Drilling muds are complex fluids, generally used to clean the well, maintain hole integrity, transport the rock cuttings, lubricate the drill bit and control formation pressures. Two basic types of drilling fluids are used, water based muds (WBM) and oil based muds (OBM). OBM are very effective but polluting, and environmental regulations continue to restrict the use of oil based muds in many areas of the world. In order to reduce the mud toxicity, we developed water based mud systems using two biopolymers, which are xanthan gum and scleroglucan, generally proposed for high permeability reservoirs or for complex geometries such as horizontal wells. In this study, we evaluated the rheological behaviour of different samples and we determined the effect of components such as clay, calcium carbonate and potassium chloride. This formulations exhibit non-Newtonian rheological behaviour which can be described well by the tree parameter in Herschel–Bulkley rheological model. 相似文献
47.
Samira T. Rabie Mahmoud A. Abd‐El‐Ghaffar Ahmed E. Ahmed Magdy W. Sabaa 《乙烯基与添加剂工艺杂志》2013,19(4):293-301
Polycondensation adducts formed by the reaction of maleic anhydride with some Polyalcohols, namely, phloroglucinol, glycerol, and ethylene glycol, were prepared, characterized, and investigated as photostabilizers for polystyrene. Their Photostabilizing effectiveness was evaluated by measuring the extent of weight loss (%), the amount of gel formed as well as the viscosity average molecular weight of the soluble fractions of the degraded polymer. The results indicated better stabilizing effects of these stabilizers compared with that of the UV absorber, phenyl salicylate. A synergistic effect was achieved when the investigated photostabilizers were mixed with phenyl salicylate in a weight ratio of 1 : 1, and a radical mechanism is proposed to account for the action of the polycondensation adducts as photostabilizers. J. VINYL ADDIT. TECHNOL., 19:293–301, 2013. © 2013 Society of Plastics Engineers 相似文献
48.
Ahmed Ouali Mohammed Gagaoua Yasmine Boudida Samira Becila Abdelghani Boudjellal Carlos H. Herrera-Mendez Miguel A. Sentandreu 《Meat science》2013
Biomarkers of the meat quality are of prime importance for meat industry, which has to satisfy consumers' expectations and, for them, meat tenderness is and will remain the primary and most important quality attribute. The tenderization of meat starts immediately after animal death with the onset of apoptosis followed by a cooperative action of endogenous proteolytic systems. Before consideration of the biomarkers identified so far, we present here some new features on the apoptotic process. Among them, the most important is the recent discovery of a complex family of serpins capable to inhibit, in a pseudo-irreversible manner, caspases, the major enzymes responsible of cell dismantling during apoptosis. The biomarkers so far identified have been then sorted and grouped according to their common biological functions. All of them refer to a series of biological pathways including glycolytic and oxidative energy production, cell detoxification, protease inhibition and production of Heat Shock Proteins. Some unusual biomarkers are also presented: annexins, galectins and peroxiredoxins. On this basis, a detailed analysis of these metabolic pathways allowed us to identify some domains of interest for future investigations. It was thus emphasized that mitochondria, an important organelle in the production of energy from carbohydrates, lipids and proteins are a central element in the initiation and development of apoptosis. It was therefore stressed forward that, in fact, very little is known about the postmortem fate of these organelles and their multiple associated activities. Other topics discussed here would provide avenues for the future in the context of identifying reliable predictors of the ultimate meat tenderness. 相似文献
49.
The plasma focus discharge can generate, accelerate and pinch the plasma up to high density and temperature in a pulsed mode
manner. Applications aspects of discharge require high efficiency of the fusion products. This situation acquires optimized
operational parameters for the proper discharge. In this article, we have studied the plasma parameters and neutron performance
dependency on bank energy. First, analytical expressions are derived from the equation of motion for the plasma particles
in the radial phase. Then, the related fusion neutrons, both thermal and non-thermal, together with the discharge anisotropy
in the low pressure regimes for the ‘Dena’ plasma focus device as function of bank energy are presented. The analytic models
are compared with experimental data. 相似文献
50.
The study evaluated the potential mismatch between classroom furniture dimensions and anthropometric characteristics of 978 Iranian high school students (498 girls, 480 boys), aged 15-18 years. Nine anthropometric measurements (stature, sitting height, sitting shoulder height, popliteal height, hip breadth, elbow-seat height, buttock-popliteal length, buttock-knee length and thigh clearance) and five dimensions from the existing classroom furniture were measured and then compared together (using match criterion equations) to identify any potential mismatch between them. The results indicated a considerable mismatch between body dimensions of the students and the existing classroom furniture, with seat height (60.9%), seat width (54.7%) and desktop height (51.7%) being the furniture dimensions with a higher level of mismatch. The levels of mismatch varied between the high-school grade levels and between genders, indicating their special requirements and possible problems. The proposed dimensions of the classroom furniture more appropriate for the students were given. This additional information on students' anthropometry can be used by local furniture industries as a starting point for designing more appropriate furniture for school children, or used by schools to aid in furniture selection. 相似文献