全文获取类型
收费全文 | 910篇 |
免费 | 28篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 19篇 |
综合类 | 2篇 |
化学工业 | 119篇 |
金属工艺 | 65篇 |
机械仪表 | 28篇 |
建筑科学 | 23篇 |
矿业工程 | 2篇 |
能源动力 | 54篇 |
轻工业 | 39篇 |
水利工程 | 18篇 |
石油天然气 | 5篇 |
无线电 | 127篇 |
一般工业技术 | 253篇 |
冶金工业 | 83篇 |
原子能技术 | 7篇 |
自动化技术 | 96篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 24篇 |
2021年 | 25篇 |
2020年 | 23篇 |
2019年 | 36篇 |
2018年 | 43篇 |
2017年 | 29篇 |
2016年 | 30篇 |
2015年 | 28篇 |
2014年 | 48篇 |
2013年 | 69篇 |
2012年 | 43篇 |
2011年 | 50篇 |
2010年 | 49篇 |
2009年 | 44篇 |
2008年 | 29篇 |
2007年 | 31篇 |
2006年 | 21篇 |
2005年 | 23篇 |
2004年 | 22篇 |
2003年 | 25篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 17篇 |
1999年 | 16篇 |
1998年 | 26篇 |
1997年 | 8篇 |
1996年 | 15篇 |
1995年 | 14篇 |
1994年 | 10篇 |
1993年 | 18篇 |
1992年 | 7篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1970年 | 3篇 |
1968年 | 1篇 |
排序方式: 共有940条查询结果,搜索用时 0 毫秒
91.
Vidyut Dey Dilip Kumar Pratihar G.L. Datta M.N. Jha T.K. Saha A.V. Bapat 《Journal of Materials Processing Technology》2009,209(3):1151-1157
Bead-on-plate welds were carried out on austenitic stainless steel plates using an electron beam welding machine. Experimental data were collected as per central composite design and regression analysis was conducted to establish input–output relationships of the process. An attempt was made to minimize the weldment area, after satisfying the condition of maximum bead penetration. Thus, it was posed as a constrained optimization problem and solved utilizing a Genetic Algorithm with a penalty function approach. The Genetic Algorithm was able to determine optimal weld-bead geometry and recommend the necessary process parameters for the same. 相似文献
92.
Nghiem Van Nguyen Jae-chun Lee Soo-kyoung Kim Manis Kumar Jha Kang-Sup Chung Jinki Jeong 《Gold bulletin》2010,43(3):200-208
Advanced hydrometallurgical separation processes are gaining significant importance for the recovery of gold from the aqueous
solutions viz. leach liquor of waste electronics, plating material solutions, and waste wash water from electronic industries.
In the present investigation, gold adsorption from the waste rinse water of semiconductor manufacturing industries is reported
using Amberlite XAD-7HP. For experimental purposes, chloride waste rinse water that contained primarily Au (281 mg/ L) with
trace amounts of Cu, Ni, Zn, Sn etc was used. Batch studies were carried out to optimize various process parameters, including
contact time, acidity of solution, and resin dosage for the adsorption of gold from the above waste effluent. Adsorption of
92.25% gold was found from the waste solution within a contact time of 30 minutes at an aqueous to resin (A/R) ratio of 25
mL/g and an equilibrium pH of 0.63. In optimal conditions, the loading capacity of resin for gold was observed to be 58.82
mg of gold/g of resin. The gold adsorption phenomena were confirmed by the comparative FT-IR spectroscopic characterization
studies of fresh resin and gold loaded resin. Elution tests were carried out for the elution of gold from the gold loaded
resin using various ratio mixtures of acetone and 1.0 M HCl. An elution efficiency of 96.96% gold was achieved at an acetone-to-acid
ratio of 9. In this condition, gold-enriched solution containing 7,240 mg gold/ L was obtained. The maximum elution of gold
was found to be 99.33% using pure acetone in a contact time of 30 minutes. The data obtained will be useful to simulate the
continuous gold adsorption process within a column. 相似文献
93.
Consumer's acceptance of tomato juice depends on its sourness to sweetness ratio and measuring this is important for quality control and marketing. Traditional methods destroy the samples, are time consuming and cannot be used in continuous packing or bottling systems. A non‐destructive method of quality evaluation, using near infrared (NIR) techniques, was tested, by using a portable NIR measuring unit. Spectra of tomato juice of known acid and brix values were determined and, in the wavelength range 703–1124 nm (NIR), a calibration model for acid–brix ratio (ABR) was developed, by using unscrambler software. When used to predict ABR of tomato juice statistical analysis showed minimal standard error (0.009) and satisfactorily high correlation coefficients (0.92) over the wavelength range 1059.5–1124.8 nm, for both calibration and prediction. These values were hardly different from analytical results and the NIR model has potential for non‐destructive prediction of ABR of tomato juice. 相似文献
94.
A case of unicystic ameloblastoma which recurred after 15 years showing unusual histological features is reported. The prominent pseudo-glandular features present are described. This case highlights the importance of extensive histological examination for more characteristic features of ameloblastoma to reach a correct diagnosis. 相似文献
95.
Computer simulations have shown a novel geodesic splitting on the paraboloid of revolution leading to a multiplicity of surface ray paths. Such a phenomenon would have wide ramifications for wave propagation problems in general, besides applications in target-detection problems and the computational requirements of ray-theoretic formulations such as the UTD, in computing the antenna characteristics in the high-frequency domain.<> 相似文献
96.
We describe a Java implementation of a policy based bandwidth management system using the standard policy protocols and an interface to the Linux Diffserv implementation. The useful features, such as extensibility and object orientation, of the Java implementation is illustrated by directly referring to the relevant programming codes. Through two practical experiments, we demonstrate the capability of our implementation in supporting policy‐based dynamic resource allocations in enterprise networks. Copyright © 2003 John Wiley &Sons, Ltd. 相似文献
97.
Srinivasan Srikanth Ajay Kumar Ray Amitava Bandopadhyay Bandari Ravikumar Animesh Jha 《Journal of the American Ceramic Society》2005,88(9):2396-2401
The phase constitution during the sintering of pure red mud and red mud–fly ash mixtures was studied in the temperature range of 900°–1250°C. The phases formed at different sintering temperatures were analyzed by X-ray powder diffraction. The phases that are likely to form at equilibrium at any isotherm were predicted using the Gibbs free energy minimization technique and the databases provided in the FactSage software. Although the thermodynamic prediction is in reasonable agreement with the experimental results for the major phases, there is some disagreement regarding the minor phases, especially the more complex phases. The major limitation of the thermodynamic approach presently is the non-availability of thermodynamic data for several complex and multi-component solution phases. 相似文献
98.
A higher-order shear and normal deformations plate theory is employed for stress analysis and free vibration of functionally graded (FG) elastic, rectangular, and simply (diaphragm) supported plates. Although functionally graded materials (FGMs) are highly heterogeneous in nature, they are generally idealized as continua with their mechanical properties changing smoothly with respect to the spatial coordinates. This idealization is required in order to obtain the closed-form solutions of some fundamental solid mechanics problems and also simplify the evaluation and development of numerical models of the structures made of FGMs. The material properties of FG plates such as Young’s moduli and material density are considered in this case to vary continuously in the thickness direction according to the volume fraction of constituents and mathematically modeled as exponential and power law functions. Poisson’s ratio is assumed to be constant. The effect of variation of material properties in terms of material grading index on the deformations, stresses, and natural frequency of FG plates is studied. The accuracy of the presented numerical solutions has been established with the solutions available of other models and the exact three-dimensional (3D) elasticity solutions. 相似文献
99.
F. Litimein R. Khenata Sanjeev K. Gupta G. Murtaza Ali. H. Reshak A. Bouhemadou S. Bin Omran Masood Yousaf Prafulla K. Jha 《Journal of Materials Science》2014,49(22):7809-7818
We performed ab initio calculations using the FPLAW method with the local density approximation (LDA) implemented in the WIEN2 k code for the orthorhombic (α) and triclinic (β) phases of BiNbO4. The modified Becke–Johnson exchange potential (mBJ)-LDA approach was also used to improve the electronic properties. The lattice constants calculated for both structures using the LDA are in good agreement with the experimental values. For the band structure calculations, the mBJ-LDA approach provides reasonable agreement for the band gap value compared with the LDA. The estimated (mBJ)-LDA band gap values are 2.89 eV (3.73 eV) and 2.62 eV (3.15 eV) for the α and β phases of BiNbO4, respectively. Significant optical anisotropy is clearly observed in the visible-light region. We also calculated and evaluated the electron energy loss spectrum for BiNbO4. This work provides the first quantitative theoretical prediction of optical properties and electron energy loss spectra for both the orthorhombic and triclinic phases of BiNbO4. 相似文献
100.
Priyanka A. Jha A. K. Jha 《Journal of Materials Science: Materials in Electronics》2014,25(2):797-804
Nano-structuring of various ferroic materials has tailored the existing properties in their bulk counterpart. Keeping this fact in view, nano-crystalline barium zirconate titanate (BaZr0.05Ti0.95O3) ferroelectric ceramics were prepared by mechanical activation process using high-energy planetary ball milling followed by the sintering process. In the present work, effect of milling duration (15, 30 and 45 h) on structural and microstructural properties has been observed with the help of X-ray diffraction, scanning electron microscopy and transmission electron microscopy (for optimized milling duration). The crystallite size of the milled specimen decreases to 14.17 nm on increasing the milling duration from 15 to 45 h. A comparison with its bulk counterpart showed significant enhancement in di-, ferro-, piezo- and pyro-electric properties with strong blue emission in UV light (265 nm). The blue emission in UV light makes it a potential candidate for LEDs and optical devices. 相似文献