全文获取类型
收费全文 | 853篇 |
免费 | 35篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 22篇 |
化学工业 | 216篇 |
金属工艺 | 16篇 |
机械仪表 | 23篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 67篇 |
轻工业 | 62篇 |
水利工程 | 8篇 |
石油天然气 | 2篇 |
无线电 | 86篇 |
一般工业技术 | 180篇 |
冶金工业 | 92篇 |
原子能技术 | 4篇 |
自动化技术 | 104篇 |
出版年
2023年 | 17篇 |
2022年 | 37篇 |
2021年 | 28篇 |
2020年 | 36篇 |
2019年 | 28篇 |
2018年 | 27篇 |
2017年 | 47篇 |
2016年 | 38篇 |
2015年 | 22篇 |
2014年 | 25篇 |
2013年 | 48篇 |
2012年 | 36篇 |
2011年 | 43篇 |
2010年 | 24篇 |
2009年 | 27篇 |
2008年 | 42篇 |
2007年 | 27篇 |
2006年 | 15篇 |
2005年 | 24篇 |
2004年 | 9篇 |
2003年 | 12篇 |
2002年 | 16篇 |
2001年 | 11篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 26篇 |
1997年 | 17篇 |
1996年 | 22篇 |
1995年 | 6篇 |
1994年 | 16篇 |
1993年 | 6篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 14篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1971年 | 3篇 |
排序方式: 共有893条查询结果,搜索用时 15 毫秒
11.
V. R. Pai Verneker K. Kishore C. B. V. Subhas 《Propellants, Explosives, Pyrotechnics》1979,4(4):83-86
Thermal decomposition studies on double-base propellants have been carried out in air and vacuum using differential scanning calorimetric, thermogravimetric and mass spectrometric techniques. Low temperature (90 °C–170 °C) decomposition seems to involve diffusion controlled process, the mechanism in air and vacuum being different. High temperature (170 °–205 °C) decomposition involves bond breakage. 相似文献
12.
The effect of slip in flows of power-law liquids past smooth spherical particles is numerically studied by using Navier’s linear slip model. For computational simplicity, a sphere-in-sphere type computational domain has been chosen. Thus, the governing conservation equations of mass and momentum are considered in spherical coordinates. These are solved by using a finite difference method-based simplified marker and cell algorithm implemented on a staggered grid arrangement. The non-Newtonian terms of the momentum equation are discretized by a second-order central differencing scheme, whereas the convective terms are discretized by using QUICK scheme. The reliability and accuracy of the solver is established by comparing the present numerical results with the existing literature counterparts. Furthermore, extensive new results are obtained in the range of conditions for Reynolds number, Re: 0.1–200; power-law behavior index, n: 0.5–1.6; and a dimensionless slip parameter, λ: 0.01–100. Finally, effects of these dimensionless parameters on near surface flow kinematics are thoroughly delineated. 相似文献
13.
Heat transfer from spheres can be influenced by a varying degree of slip at the fluid‐particle interface along with the rheology of the surrounding continuous liquid and adjacent spheres. Thus in this study, the effects of dimensionless velocity slip parameter (λ) along with power‐law fluid rheology and other pertinent kinematic flow and heat transfer parameters on isotherm contours, local and average Nusselt numbers of assemblages of spherical slip particles are presented. This is done by adopting a segregated approach where dimensionless momentum and energy equations are solved by SMAC algorithm formulated in spherical coordinates within the finite difference formulation. Before obtaining new results, grid independence studies for either extreme values of power‐law consistency index of non‐Newtonian fluids are carried out. Finally, the major contribution of this study is the development of a correlative equation for the average Nusselt number of assemblages of spherical slip particles in power‐law fluids based on the present results (5880 data points) as a function of pertinent dimensionless parameters. 相似文献
14.
15.
16.
Ritesh KrishnaSatyadarshi Nanda Abhijit Kulkarni Sangameshwar Patil 《Computers & Chemical Engineering》2011,35(1):121-126
In this article, we utilize the concept of partial Granger causality to study the penicillin production process under several operating conditions. We propose a graph-theoretic template (causal network) based method for intelligent process monitoring. We validate our results with the aid of existing knowledge and available literature. The proposed method is quite general and can be extended to analyze several physical, chemical or biological systems. 相似文献
17.
Barsha Dash Indra Narayan Bhattacharya Bhaskara Venkata Ramanamurthy Raja Kishore Paramguru 《Korean Journal of Chemical Engineering》2011,28(7):1546-1549
An approach to produce molybdenum trioxide from spent hydrodesulfurization (HDS) catalyst, obtained from a petroleum refinery,
is presented here. The spent catalyst was devolatilized at 600 °C so as to make it free from oils, organics and other volatile
species. It was then roasted with sodium carbonate at a temperature of 850 °C for 30 min. The leaching efficiency for 20%
soda roasted sample at 10% pulp density was 99.8%. From the solution molybdenum was precipitated out as ammonium molybdate
at pH 1.0 with HCl and ammonium chloride. This ammonium molybdate was calcined at 750 °C to get MoO3. The product was characterized by XRD. Its purity was determined titrimetrically and by ICP-AES. 相似文献
18.
Effects of the confining wall or blockage on the heat transfer phenomena of spheroid particles were numerically investigated. The heated spheroid particles were maintained at constant temperature and allowed to sediment in cylindrical tubes filled with Newtonian liquids. In this flow configuration, the heat transfer took place from the heated spheroid particles to the surrounding Newtonian liquid. The governing conservation equations of the mass, momentum, and energy together with appropriate boundary conditions were numerically solved using commercial software based on computational fluid dynamics. A simple correlation for the average Nusselt number of the confined spheroid particles was developed which can be applied in new applications. 相似文献
19.
The effects of process engineering in the fabrication of PHBV, PLA and their blends prepared by melt blending are studied. The elongation of an optimized blend can be improved by 148 and 250% over the virgin PHBV and PLA polymers, respectively. DSC shows that the two polymers are immiscible in blends of any composition. The crystallinity of PHBV is hindered by the presence of PLA. UV‐Vis demonstrates the opacity of the blend with incorporation of PHBV to the PLA phase. The observed tensile modulus of the optimized sample is compared with theoretical values from the rule of mixtures. Gordon‐Taylor's equation is applied on the glass transition temperatures for theoretical modeling to explain the miscibility of the polymers.
20.
A blend composition of poly(3‐hydroxybutyrate‐co‐valerate) and polylactide is used as a bioplastic matrix and reinforced with soy hull to engineer novel green composites. A comparative study with soy‐hull‐reinforced polypropylene composite system is performed. A compatibilizer is used to engineer the novel class of green composites with a balanced stiffness and toughness performance with the target to substitute PP‐based composites. The flexural and impact strength along with hydrophobicity of compatibilized composites are improved significantly over the noncompatibilized counterpart. The fiber/matrix interaction is investigated by SEM. These green composites have the potential to substitute PP‐based composites in some applications.