全文获取类型
收费全文 | 1888篇 |
免费 | 76篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 23篇 |
综合类 | 4篇 |
化学工业 | 574篇 |
金属工艺 | 74篇 |
机械仪表 | 88篇 |
建筑科学 | 39篇 |
矿业工程 | 6篇 |
能源动力 | 67篇 |
轻工业 | 147篇 |
水利工程 | 14篇 |
石油天然气 | 7篇 |
无线电 | 149篇 |
一般工业技术 | 269篇 |
冶金工业 | 180篇 |
原子能技术 | 18篇 |
自动化技术 | 309篇 |
出版年
2023年 | 6篇 |
2022年 | 70篇 |
2021年 | 98篇 |
2020年 | 42篇 |
2019年 | 52篇 |
2018年 | 55篇 |
2017年 | 77篇 |
2016年 | 81篇 |
2015年 | 57篇 |
2014年 | 97篇 |
2013年 | 146篇 |
2012年 | 95篇 |
2011年 | 101篇 |
2010年 | 89篇 |
2009年 | 96篇 |
2008年 | 104篇 |
2007年 | 70篇 |
2006年 | 67篇 |
2005年 | 45篇 |
2004年 | 43篇 |
2003年 | 47篇 |
2002年 | 26篇 |
2001年 | 16篇 |
2000年 | 24篇 |
1999年 | 20篇 |
1998年 | 29篇 |
1997年 | 25篇 |
1996年 | 26篇 |
1995年 | 21篇 |
1994年 | 22篇 |
1993年 | 17篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 14篇 |
1987年 | 9篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 19篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1975年 | 4篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1971年 | 6篇 |
排序方式: 共有1968条查询结果,搜索用时 718 毫秒
1.
2.
Theoretical Foundations of Chemical Engineering - The extraction of nitric and oxalic acids by neutral compounds TBP, DBBP, and TBPO have been studied. The optimal conditions of their separation... 相似文献
3.
Kazantsev Yu. N. Kraftmakher G. A. Mal’tsev V. P. 《Journal of Communications Technology and Electronics》2019,64(6):550-554
Journal of Communications Technology and Electronics - Approximate formulas for calculating the coefficient of reflection from an artificial magnetic conductor (AMC) based on a capacitive lattice... 相似文献
4.
Chouping Luo Marek Klisinski 《International journal for numerical methods in engineering》2004,61(2):159-188
The present study is a continuation of our previous work with the aim to reduce problems caused by standard higher order elements in contact problems. The difficulties can be attributed to the inherent property of the Galerkin method which gives uneven distributions of nodal forces resulting in oscillating contact pressures. The proposed remedy is use of piece‐wise linear weight functions. The methods to establish stiffness and/or mass matrix for 8‐node quadrilateral element in 2D are presented, i.e. the condensing and direct procedures. The energy and nodal displacement error norms are also checked to establish the convergence ratio. Interpretation of calculated contact pressures is discussed. Two new 2D 8‐node quadrilateral elements, QUAD8C and QUAD8D, are derived and tested in many examples, which show their good performance in contact problems. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
5.
Identification of critical erosion prone areas in the small agricultural watershed using USLE,GIS and remote sensing 总被引:10,自引:1,他引:9
In the present study, Karso watershed of Hazaribagh, Jharkhand State, India was divided into 200 × 200 grid cells and average
annual sediment yields were estimated for each grid cell of the watershed to identify the critical erosion prone areas of
watershed for prioritization purpose. Average annual sediment yield data on grid basis was estimated using Universal Soil
Loss Equation (USLE). In general, a major limitation in the use of hydrological models has been their inability to handle
the large amounts of input data that describe the heterogeneity of the natural system. Remote sensing (RS) technology provides
the vital spatial and temporal information on some of these parameters. A recent and emerging technology represented by Geographic
Information System (GIS) was used as the tool to generate, manipulate and spatially organize disparate data for sediment yield
modeling. Thus, the Arc Info 7.2 GIS software and RS (ERDAS IMAGINE 8.4 image processing software) provided spatial input
data to the erosion model, while the USLE was used to predict the spatial distribution of the sediment yield on grid basis.
The deviation of estimated sediment yield from the observed values in the range of 1.37 to 13.85 percent indicates accurate
estimation of sediment yield from the watershed. 相似文献
6.
7.
Marek Markowski Ireneusz Bialobrzewski Janusz Bowszys Stanislaw Suchecki 《Drying Technology》2007,25(9):1527-1536
A neural-deterministic simulation model applied for calculating distributions of temperatures and moisture content in a bed of wheat stored in a steel silo without aeration is presented in the article. The model consists of differential equations of heat and moisture transfer, initial and boundary conditions, and three artificial neural networks used during simulated ambient air conditions. Experiments and computer simulations were carried out in order to determine temperature fields in wheat grain stored in a steel silo for two months. The computer simulations were carried using MATLAB and FEMLAB software. The difference between measured and simulated temperature in grain near the silo wall at a height of 2.5 m from the bottom was less than 3.0°C. On the basis of the analysis performed it was concluded that the temperature distributions obtained with the model were consistent with the measured results obtained for grain stored in a steel silo without aeration. 相似文献
8.
Marek Gondzio 《Software》1987,17(3):215-226
Every microprocessor-based system needs powerful debugging tools. Debugging power strongly depends on a mechanism of control exchange between the debugger and an application program. Several implementation methods of such a mechanism are briefly described and compared in this paper. It is shown that conditional breakpoints facilitate a semantics-oriented approach to program debugging. Some debugging techniques derived from elementary control-exchange mechanisms are proposed. Most of the techniques discussed are implemented in the MD-86 debugger designed for the Intel 8086 microprocessor. The debugger itself is also briefly described. 相似文献
9.
Marek Pronobis 《Fuel》2006,85(4):474-480
The paper presents an attempt to evaluate the influence of biomass co-combustion on the fouling of boiler convection surfaces. In order to show the influence of co-firing biomass with bituminous coal on boiler efficiency, the calculations of pulverized fuel (PF) OP 140 steam generator have been carried out. Typical Upper Silesian coal with medium fouling inclination has been chosen as a basic fuel. Three kinds of biomass have been taken into consideration: straw, wood and dried sewage sludge. The results confirm that the properties of additional fuels cause deterioration of the boiler efficiency as well as the changes in boilers operational parameters (amount of water injected in attemperators, ash stream, hot air temperature). The biomass during cofiring in fact replaces the coal, but always the additional fuel consumption is higher than that of the substituted coal. Therefore, the actual decrease of coal consumption is smaller than the thermal fraction of the biomass. 相似文献
10.
Voting in Multi-Agent Systems 总被引:1,自引:0,他引:1