全文获取类型
收费全文 | 512篇 |
免费 | 20篇 |
专业分类
电工技术 | 6篇 |
综合类 | 1篇 |
化学工业 | 148篇 |
金属工艺 | 5篇 |
机械仪表 | 15篇 |
建筑科学 | 16篇 |
能源动力 | 38篇 |
轻工业 | 62篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 17篇 |
一般工业技术 | 77篇 |
冶金工业 | 43篇 |
原子能技术 | 7篇 |
自动化技术 | 93篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 10篇 |
2021年 | 31篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 22篇 |
2013年 | 28篇 |
2012年 | 29篇 |
2011年 | 36篇 |
2010年 | 26篇 |
2009年 | 29篇 |
2008年 | 28篇 |
2007年 | 14篇 |
2006年 | 15篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 10篇 |
2002年 | 17篇 |
2001年 | 11篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1962年 | 1篇 |
1949年 | 1篇 |
排序方式: 共有532条查询结果,搜索用时 0 毫秒
41.
Frank D. Macías-Escrivá Rodolfo Haber Raul del Toro Vicente Hernandez 《Expert systems with applications》2013,40(18):7267-7279
Self-adaptive software is capable of evaluating and changing its own behavior, whenever the evaluation shows that the software is not accomplishing what it was intended to do, or when better functionality or performance may be possible. The topic of system adaptivity has been widely studied since the mid-60s and, over the past decade, several application areas and technologies relating to self-adaptivity have assumed greater importance. In all these initiatives, software has become the common element that introduces self-adaptability. Thus, the investigation of systematic software engineering approaches is necessary, in order to develop self-adaptive systems that may ideally be applied across multiple domains. The main goal of this study is to review recent progress on self-adaptivity from the standpoint of computer sciences and cybernetics, based on the analysis of state-of-the-art approaches reported in the literature. This review provides an over-arching, integrated view of computer science and software engineering foundations. Moreover, various methods and techniques currently applied in the design of self-adaptive systems are analyzed, as well as some European research initiatives and projects. Finally, the main bottlenecks for the effective application of self-adaptive technology, as well as a set of key research issues on this topic, are precisely identified, in order to overcome current constraints on the effective application of self-adaptivity in its emerging areas of application. 相似文献
42.
Marissa Vargas‐Ramirez Antonio Romero‐Serrano Rodolfo Morales Miguel Angeles‐Hernandez Federico Chavez‐Alcala Javier Castro‐Arellano 《国际钢铁研究》2001,72(5-6):173-181
A mathematical model earlier proposed has been improved to predict the kinetics of multicomponent reactions in the hot metal pretreatment through the injection of reactive fluxes. It is assumed that there are two reaction zones along the flux injection operation: a transitory reaction between the rising particles and the bulk metal, and the permanent reaction between the metal and the top slag. A criterion to estimate the fraction of solids which will react with molten iron in a three‐phase jet (gas‐solid‐liquid) was considered; this fraction of solids carries out the transitory reaction. The model also takes into account the thermodynamic changes produced in the metal and slag due to the chemical reactions. Calculated results of the model are in good agreement with experimental results for the desulfurization of hot metal through the injection of CaO‐SiO2‐CaF2‐FeO‐Na2O reagents at 1400 ‐ 1450 °C. Two kinds of hot metal were tested, one with a low carbon mass content of 3 % and the other with a high carbon mass content of 4.5 %. 相似文献
43.
The main purpose of this work is to show the ability of the TCS (task configuration system) to perform both the design and the operation optimization of power plants. The TCS is a module that permits to set the main task of each one of the equipments of the system and consequently setting how they respond to variable loads. In this work, the TCS was applied to a micro cogeneration plant of 60 kW in which both the electrical and the thermal loads were variable. Primarily, the design optimization of the nominal power of the equipments and of the TCS configuration was performed for the loads and electricity/fuel costs assumed in the design. After this operational optimizations in cases where the loads and electricity/fuel costs were doubled and then halved in relation to the standard case were performed. The results presented the TCS in a very robust way in most of the cases even the operational conditions being very different from the originally assumed. Based on the results, it is possible to defend the use of the TCS to decrease the risk of high initial investments made in cogeneration systems. 相似文献
44.
Ana Alonso Anahí Dello Russo César Otero-Souto Claudio Padra Rodolfo Rodríguez 《Computing and Visualization in Science》2001,4(2):67-78
This paper deals with the computation of the vibration modes of a system consisting of a linear elastic solid interacting
with an acoustic fluid. A finite element method based on meshes for each medium not matching on the fluid-solid interface
is analyzed. Optimal order of convergence is proved for the approximation of the eigenfunctions, as well as a double order
for the eigenvalues. Numerical tests confirming the theoretical results and showing the advantage of using non-matching grids
are reported. Finally, an a posteriori error estimator for this method is introduced and combined with a mesh refinement strategy.
The efficiency of this adaptive technique is tested with further numerical experiments.
Received: 30 January 2001 / Accepted: 30 May 2001 相似文献
45.
Rosa Montesinos Rodolfo Reynoso Fernando Álvarez César Andrés Flores 《Polymer-Plastics Technology and Engineering》2015,54(7):730-740
Novel, environmentally friendly waterborne coatings were obtained from the filmification of nanostructured latex particles reinforced with inorganic nanotubes. The latex used to form the coatings consists of core-shell particles with a shell functionalized with different amounts of acrylic acid (AA). This external polymer layer was doped, in some cases, with TiO2 nanotubes at three different concentrations: 100, 500 and 1000 ppm. The composite particles were synthesized in two steps by semi-continuous emulsion polymerization at 75°C. A series of films was prepared by employing core-shell particles with different sizes, core cross-linking and shell functionalization. The coatings obtained were characterized by infrared spectroscopy (FTIR), tapping mode atomic force microscopy (TM-AFM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetrical analysis (TGA). Drying rates and tests were also performed to further evaluate these films. It was observed that the addition of small amounts of TiO2 nanotubes contributes to improve the application properties, mainly adhesion to metallic substrates and water impermeability. The resistance to thermal degradation was also strongly increased, as showed by the DSC and TGA analyses. 相似文献
46.
47.
48.
49.
The effects of food intake and carbohydrate administration on fatty acid Δ9-desaturation were investigated in isolated microsomes from Triatoma infestans fat body. Fifth instar nymphs, which were solely blood-fed just after the molt and then fasted, were used as controls and
for determination of optimal assay conditions. Both [1-14C]palmitic and [1-14C]stearic acids in a medium containing ATP, CoA, MgCl2, NADH, NaF, and O2 were tested. For the control group, optimal conditions were a pH of 6.8–7.2, an incubation temperature of 29°C, and an incubation
time of 10 min. Δ9-desaturation depended on the presence of reduced pyridine dinucleotides; NADH and NADPH were equally efficient. Stearic acid
showed a higher apparent V
max than palmitic acid, but the apparent K
m were very similar. When fifth instar nymphs were blood-fed weekly, a marked increase of Δ9-desaturation was observed for both acids. Higher desaturation activity was also induced by injection of the carbohydrate
trehalose into the hemolymph of fasted nymphs. These results indicate that insect Δ9-desaturation, like the mammalian counterpart, is sensitive to dietary changes and carbohydrate administration. *** DIRECT
SUPPORT *** A01K6035 00008 相似文献
50.
We present in this paper an analysis of a semi-Lagrangian second order Backward Difference Formula combined with hp-finite
element method to calculate the numerical solution of convection diffusion equations in ℝ2. Using mesh dependent norms, we prove that the a priori error estimate has two components: one corresponds to the approximation
of the exact solution along the characteristic curves, which is
O(Dt2+hm+1(1+\frac\mathopen|logh|Dt))O(\Delta t^{2}+h^{m+1}(1+\frac{\mathopen{|}\log h|}{\Delta t})); and the second, which is O(Dtp+|| [(u)\vec]-[(u)\vec]h||L¥)O(\Delta t^{p}+\| \vec{u}-\vec{u}_{h}\|_{L^{\infty}}), represents the error committed in the calculation of the characteristic curves. Here, m is the degree of the polynomials in the finite element space, [(u)\vec]\vec{u} is the velocity vector, [(u)\vec]h\vec{u}_{h} is the finite element approximation of [(u)\vec]\vec{u} and p denotes the order of the method employed to calculate the characteristics curves. Numerical examples support the validity
of our estimates. 相似文献