全文获取类型
收费全文 | 464篇 |
免费 | 25篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 32篇 |
综合类 | 3篇 |
化学工业 | 90篇 |
金属工艺 | 11篇 |
机械仪表 | 14篇 |
建筑科学 | 6篇 |
能源动力 | 29篇 |
轻工业 | 30篇 |
水利工程 | 1篇 |
无线电 | 42篇 |
一般工业技术 | 86篇 |
冶金工业 | 49篇 |
原子能技术 | 4篇 |
自动化技术 | 106篇 |
出版年
2024年 | 2篇 |
2023年 | 19篇 |
2022年 | 22篇 |
2021年 | 26篇 |
2020年 | 22篇 |
2019年 | 17篇 |
2018年 | 34篇 |
2017年 | 16篇 |
2016年 | 17篇 |
2015年 | 8篇 |
2014年 | 19篇 |
2013年 | 53篇 |
2012年 | 27篇 |
2011年 | 25篇 |
2010年 | 21篇 |
2009年 | 15篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 6篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有503条查询结果,搜索用时 15 毫秒
101.
The paper presents a new approach for the protection of power transmission lines using a minimal radial basis function neural network (MRBFNN). This type of RBF neural network uses a sequential learning procedure to determine the optimum number of neurons in the hidden layer without resorting to trial and error. The input data to this network comprises fundamental peak values of relaying point voltage and current signals, the zero-sequence component of current and system operating frequency. These input variables are obtained by a Kalman filtering approach. Further, the parameters of the network are adjusted using a variant of extended Kalman filter known as locally iterated Kalman filter to produce better accuracy in the output for harmonics, DC offset and noise in the input data. The number of training patterns and the training time are drastically reduced and significant accuracy is achieved in different types of fault classification and location in transmission lines using computer simulated tests 相似文献
102.
The ZrCo intermetallic is considered to be strategically important for hydrogen isotope storage and its use in the International Thermonuclear Experimental Reactor (ITER) system. Here we report the structural, electronic and thermodynamic properties of ZrCo and ZrCoH3 using the first-principles approach. The calculations are performed using a plane-wave based pseudo-potential approach under the framework of spin-polarized density-functional theory. The ground state properties like lattice constants, bulk moduli, and enthalpy of formation have been determined by optimizing the atomic and electronic structure of ZrCo and ZrCoH3 compounds. From the total energy calculations, the enthalpy of formation of ZrCoH3 from ZrCo is estimated to be −91 kJ/mol H2 at 0 K. Both lattice parameters and formation energy are found to be in good agreement with their corresponding experimental values. The nature of chemical bonding in ZrCo and ZrCoH3 has been analyzed from the electronic density of states spectrum of the constituent materials. 相似文献
103.
N. Kumar Neha SharmaS. Dash C. PopovW. Kulisch J.P. ReithmaierG. Favaro A.K. TyagiBaldev Raj 《Tribology International》2011,44(12):2042-2049
Transformation from higher to ultra low friction coefficient was observed in ultrananocrystalline diamond film (UNCD) while changing the test atmospheric conditions. High friction coefficients were observed in dry argon and nitrogen atmosphere, however, low and ultra low friction coefficients were obtained in dry oxygen and in ambient atmospheric conditions, respectively. Wear rates follow the same trends as the friction coefficients. This fascinating behavior of friction and wear of UNCD film is explained by the chemical changes of sliding surfaces and extent of passivation of dangling covalent bonds. 相似文献
104.
Silicon carbide nanotubes were found to grow in straight as well as curved configurations by treating silicon carbide grains in an arc plasma reactor/furnace followed by 3 h of cooling (in air). By increasing the plasma treatment time from 16 min to 20 min, multi-wall tubes were found to change to single wall tubes with reduction in diameter from few nm to sub-nm. Typical in situ grown nanotubes were characterized by XRD, TEM, SAED, HRTEM, EDS and micro Raman spectroscopy, and it is established from these evaluations that the nanotubes are made up of silicon carbide and not carbon. A possible mechanism, involving reaction between the plasma dissociated carbon (solid) forming carbon nanotube and the left-out silicon (existing in vapour state) during the cooling period (3000–2680 °C), is suggested to be responsible for silicon carbide nanotube formation in the plasma assisted process. 相似文献
105.
Advancement of an efficient and cost-effective method for heavy metal removal from contaminated water utilising Fe3O4–APTES–EDTA (FAE) nanocomposite, a productive reusable adsorbent, is explained in this study. The novel FAE nanocomposite was prepared and characterised using different techniques such as FTIR, XRD, TEM, EDS, BET, TGA, EDX and Zeta potential techniques. FAE is found to be a good adsorbent for Pb2+, Cd2+, Ni2+, Co2+ and Cu2+ removal with a higher adsorption capacity. The maximum adsorption capacity of Pb2+, Cd2+, Ni2+, Co2+ and Cu2+ are found to be 11.31, 13.88, 7.64, 4.86 and 78.67 mg/g, respectively. The adsorption and desorption cycle was studied for five cycles with minimal loss of efficiency. 相似文献
106.
ShyamalRao Polaki Rajagopalan Ramaseshan Feby Jose Nukala Ravi Sitaram Dash Ashok Kumar Tyagi 《International Journal of Applied Ceramic Technology》2013,10(1):45-50
We investigate the effect of orientation and residual stress on mechanical properties of reactive magnetron‐sputtered TiN thin films on SS 304 LN with a function of substrate temperature. All these films are polycrystalline with a preferred orientation (200). Residual stress of these films were calculated by sin2Ψ technique and found to be in the range of ?2.6 to ?4.5 GPa. The hardness and modulus of these films ranged between 24–29 GPa and 326–388 GPa, respectively. Temperature‐dependent orientation change is clearly observed and this in turn influenced the residual stress. Hardness and modulus of these films exhibited dependence on the orientation and residual stress. 相似文献
107.
Evans Afriyie-Gyawu John Mackie Bhagirathi Dash Melinda Wiles John Taylor Henry Huebner Lili Tang Hongxia Guan Jia-Sheng Wang Timothy Phillips 《Food Additives & Contaminants》2005,22(3):259-269
NovaSil (NS) clay, a common anti-caking agent in animal feeds, has been shown to sorb aflatoxins in the GI tract and diminish their bioavailability and adverse effects in short-term animal studies. Based on this evidence, it is hypothesized that clay-based enterosorption of aflatoxins may be a useful strategy for the prevention of aflatoxicosis in human populations. However, the potential toxicity of long-term dietary exposure to NS has not been determined. In this research, 5-6-week-old male and female Sprague-Dawley rats were fed rations containing 0, 0.25, 0.5, 1.0, or 2.0% (w/w) levels of NS for 28 weeks. Analysis of the NS showed negligible levels of dioxin and furan contaminants. Total feed consumption, cumulative feed consumption, body weight, total body weight gain, feed conversion efficiency, cumulative feed conversion efficiency, and relative organ weights were unaffected in either sex at the doses tested. No NS-dependent differences in relative organ weights or gross or histopathological changes were observed. Analysis of hematological parameters, clinical chemistry, and selected vitamin and mineral levels revealed isolated significant differences between some treatments and control groups (mean corpuscular hemoglobin, serum Ca, serum vitamin A, and serum Fe). However, the differences observed in each case were not dose-dependent. These results suggest that dietary inclusion of NS at levels as high as 2.0% (w/w) does not result in overt toxicity. These findings (as well as others) support the use of NS clay for dietary intervention studies in human populations at high risk for aflatoxicosis. 相似文献
108.
Automatic Classification of Cardiac Arrhythmias Based on Hybrid Features and Decision Tree Algorithm
Machine Intelligence Research - Accurate classification of cardiac arrhythmias is a crucial task because of the non-stationary nature of electrocardiogram (ECG) signals. In a life-threatening... 相似文献
109.
110.
The squeezing flow of an unsteady water‐based nanofluid between two parallel disks has been analyzed in the current study. Thermal and solutal buoyancy along with heat source enhance the flow phenomena of free convective flow through a porous medium. In addition to that velocity slip and temperature slip are also accounted for in the boundary conditions. The similarity transformation is adopted to formulate the governing equations that convert the complex partial differential equations (PDEs) to nonlinear ordinary differential equations (ODEs). These transformed equations are handled analytically by using the variation parameter method (VPM). For computational purposes, the fixed numeric values of physical parameters are used and their behaviors are shown by means of graphs. The calculated results for the physical quantities of interest are shown in tables. The conformity of the solution is obtained in comparison to an earlier study in a particular case. The major findings are (i) the velocity profile has distinct variations, which are separated by the middle layer of the channel and (ii) enhancement in the heat transfer coefficient is noted due to the interaction of buoyancy parameter. 相似文献