全文获取类型
| 收费全文 | 339篇 |
| 免费 | 2篇 |
专业分类
| 电工技术 | 6篇 |
| 综合类 | 2篇 |
| 化学工业 | 54篇 |
| 金属工艺 | 4篇 |
| 机械仪表 | 5篇 |
| 建筑科学 | 2篇 |
| 能源动力 | 43篇 |
| 轻工业 | 9篇 |
| 水利工程 | 1篇 |
| 石油天然气 | 3篇 |
| 无线电 | 74篇 |
| 一般工业技术 | 49篇 |
| 冶金工业 | 1篇 |
| 原子能技术 | 1篇 |
| 自动化技术 | 87篇 |
出版年
| 2024年 | 7篇 |
| 2023年 | 28篇 |
| 2022年 | 25篇 |
| 2021年 | 22篇 |
| 2020年 | 20篇 |
| 2019年 | 26篇 |
| 2018年 | 19篇 |
| 2017年 | 26篇 |
| 2016年 | 20篇 |
| 2015年 | 18篇 |
| 2014年 | 29篇 |
| 2013年 | 21篇 |
| 2012年 | 9篇 |
| 2011年 | 10篇 |
| 2010年 | 8篇 |
| 2009年 | 6篇 |
| 2008年 | 2篇 |
| 2007年 | 6篇 |
| 2006年 | 3篇 |
| 2005年 | 6篇 |
| 2004年 | 2篇 |
| 2003年 | 1篇 |
| 2002年 | 3篇 |
| 2001年 | 2篇 |
| 2000年 | 1篇 |
| 1998年 | 2篇 |
| 1996年 | 1篇 |
| 1995年 | 1篇 |
| 1994年 | 1篇 |
| 1992年 | 1篇 |
| 1989年 | 1篇 |
| 1987年 | 6篇 |
| 1986年 | 2篇 |
| 1985年 | 2篇 |
| 1976年 | 1篇 |
| 1970年 | 1篇 |
| 1968年 | 1篇 |
| 1966年 | 1篇 |
排序方式： 共有341条查询结果，搜索用时 15 毫秒
61.
Software reliability is one of the most important quality attributes of commercial software. During software testing, software reliability growth models (SRGMs) are commonly used to describe the phenomenon of failure occurrence and/or fault removal which consequently enhancements software reliability. Large software systems are developed by integrating a number of relatively small and independent modules, which are tested independently during module testing phase. The amount of testing resource available is limited which is desired to be consumed judiciously so as to optimize the testing process. In this paper we formulate a resource allocation problem of minimizing the cost of software testing under available amount of testing resource, given a reliability constraint. We use a flexible SRGM considering testing effort which, depending upon the values of parameters, can describe either exponential or S-shaped failure pattern of software modules. A systematic and sequential Algorithm is proposed to solve the optimization problem formulated. Numerical examples are given to illustrate the formulation and solution procedures. Sensitivity analysis is performed to examine the behavior of some parameters of SRGM with most significant influence. 相似文献
62.
Singh Pradeep Kumar Bhargava Bharat Hong Wei-Chiang Angin Pelin 《Multimedia Tools and Applications》2022,81(24):34439-34445
Multimedia Tools and Applications - 相似文献
63.
64.
65.
《Solid-state electronics》1970,13(5):609-617
The theory underlying a method for measuring carrier diffusion length based on the surface photovoltage is extended to include bulk trapping effects at low injection levels. This is done through recognizing that even in the presence of trapping when their lifetimes may differ, excess electrons and holes both diffuse in the bulk with the same characteristic length. The theory has been examined in terms of quasi-equilibrium conditions across the surface space charge layer; however, the method is expected to work under less restrictive conditions. As with no trapping, the method should yield the minority carrier diffusion length in extrinsic material for majority carrier trapping in general, but in the case of minority carrier trapping, only for moderate trapping. When strong minority carrier trapping occurs in slightly extrinsic material, the effective diffusion length, owing to trap-modified ambipolar diffusion in a Dember field, may be greater than the usual minority carrier diffusion length which obtains in the absence of trapping.A treatment of recombination statistics is included to illustrate how trapping effects may arise from the presence of deep-lying impurities such as gold in solicon. It also provides a basis for a detailed examination of the low injection-level assumptions used in simplifying the problem of trap-modified carrier diffusion in the bulk. It is shown, for example, that in extrinsic semiconductor, the usual assumptions that the excess carrier densities be much smaller than their equilibrium values need apply to majority carriers only. For minority carriers, the limitations are far less severe in most cases of practical interest, and depend on the characteristics of the trapping centers involved. 相似文献
66.
《Food research international (Ottawa, Ont.)》2002,35(2-3):177-181
We have shown recently that plant steryl and stanyl esters, used as plasma cholesterol-lowering food supplements, can be efficiently prepared from the sterols and stanols via lipase-catalysed esterification with fatty acids and transesterification with fatty acid methyl esters or triacylglycerols [Weber, N., Weitkamp, P., & Mukherjee, K. D. (2001). Journal of Agricultural and Food Chemistry, 49, 67–71]. In continuation of this work, sterols contained in three different steam distillates obtained from rapeseed oil by conventional deodorization or from rapeseed oil or a mixture of soybean and rapeseed oils by physical refining have been converted to a high degree in situ to the corresponding long-chain acyl esters via esterification and/or transesterification with fatty acids and/or triacylglycerols using lipase from Candida rugosa as biocatalyst in vacuo (20–40 mbar) at 40 °C. The steryl esters formed were purified to ⩾90% by deacidification, flash chromatography on silica gel and solvent fractionation using acetone-water (9:1,v/v). 相似文献
67.
Carbon steel is used as the primary heat transport system piping material in pressurized heavy water reactors. The carbon steel surfaces corrode during the high temperature operation. Enhanced wall thinning of the piping in locations of high velocity and neutron activation of corrosion products pose serious operational difficulties. Magnesium ion modified water chemistry resulted in significant reduction in the corrosion and corrosion release of carbon steel. The changes induced by magnesium ions in the various processes at the metal–oxide, oxide–solution interfaces, and subsequent restructuring of the oxide were identified by in situ electrochemical impedance spectroscopy. 相似文献
68.
Silicon - In this paper, we investigate the effect of low K dielectric pocket on DC and analog/RF performance in dual material stack gate oxide double gate tunnel field effect transistor. For this,... 相似文献
69.
This paper presents a physics-based compact gate delay model that includes all short-channel phenomena prevalent at the ultra-deep submicron technology node of 32 nm. To simplify calculations, the proposed model is connected to a compact α-power law-based (Sakurai-Newton) model. The model has been tested on a wide range of supply voltages. The model accurately predicts nominal delays and the delays under process variations. It has been shown that at lower technology nodes, the delay is more sensitive to threshold voltage variations, specifically at the sub-threshold operating region as compared with effective channel length variations above the threshold region. 相似文献
70.
Multimedia Tools and Applications - De-noising of images along with the edge enhancement has always been a challenging task in large scale heterogeneous image data. This paper presents a two stage... 相似文献