全文获取类型
收费全文 | 905篇 |
免费 | 78篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 16篇 |
化学工业 | 236篇 |
金属工艺 | 27篇 |
机械仪表 | 43篇 |
建筑科学 | 34篇 |
矿业工程 | 1篇 |
能源动力 | 38篇 |
轻工业 | 53篇 |
水利工程 | 21篇 |
石油天然气 | 7篇 |
无线电 | 129篇 |
一般工业技术 | 133篇 |
冶金工业 | 54篇 |
原子能技术 | 12篇 |
自动化技术 | 181篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 28篇 |
2021年 | 57篇 |
2020年 | 42篇 |
2019年 | 62篇 |
2018年 | 70篇 |
2017年 | 76篇 |
2016年 | 63篇 |
2015年 | 40篇 |
2014年 | 56篇 |
2013年 | 104篇 |
2012年 | 70篇 |
2011年 | 77篇 |
2010年 | 45篇 |
2009年 | 27篇 |
2008年 | 18篇 |
2007年 | 13篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 3篇 |
2003年 | 10篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 12篇 |
1997年 | 11篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有985条查询结果,搜索用时 62 毫秒
1.
2.
A. Vahid Shahidi I. Shih T. Araki C. H. Champness 《Journal of Electronic Materials》1985,14(3):297-310
Structural investigation on monocrystalline CuInSe2 samples has been made. From the single crystal results, the space group of CuInSe2 was confirmed to be Iˉ42d and the crystal solidification direction was investigated. Compositional uniformity of the ingots
was established by EPMA and it was found that the indium concentration was greater than that for copper. Systematic annealing
experiments were carried out in vacuum at different temperatures (as low as 160° C) and for different times. Large variation
in resistivity was observed after the annealing treatment. P-type samples were found to convert to n-type after the heat-treatments. 相似文献
3.
Anmar W. Sabri Zainab H. Ali Serwan F. Shawkat Lamia A. Thejar Thaer I. Kassim Khalid A. Rasheed 《河流研究与利用》1993,8(3):237-250
The influences of the Samarra impoundment on the ecology of the downstream sector of the river Tigris are investigated. Zooplankton were collected monthly from July 1987 to July 1988. It was found that zooplankton were most abundant during high river discharges in March. During the month of low river discharge, September, the zooplankton population was greatly reduced immediately below the barrage and remained so to the last downstream station. Several factors seem to explain such differences. The high discharge from the impoundment was found to be the dominating factor and may flush the small backwaters in which zooplankton were abundant, thus increasing the population in the river. Zooplankton species vary in their ability to sustain populations in the river, variations which are due mainly to species-specific characteristics. 相似文献
4.
Mohammad Ziabari Vahid Mottaghitalab Scott T. McGovern A. K. Haghi 《Nanoscale research letters》2007,2(12):597-600
In this paper, a new image analysis based method for electrospun nanofiber diameter measurement has been presented. The method
was tested by a simulated image with known characteristics and a real web. Mean (M) and standard deviation (STD) of fiber
diameter obtained using this method for the simulated image were 15.02 and 4.80 pixels respectively, compared to the true
values of 15.35 and 4.47 pixels. For the real web, applying the method resulted in M and STD of 324 and 50.4 nm which are
extremely close to the values of 319 and 42 nm obtained using manual method. The results show that this approach is successful
in making fast, accurate automated measurements of electrospun fiber diameters. 相似文献
5.
Extending the Kernighan/Lin Heuristic for Hardware and Software Functional Partitioning 总被引:5,自引:0,他引:5
The Kernighan/Lin graph partitioning heuristic, also known as min-cut or group migration, has been extended over several decades very successfully for circuit partitioning. Those extensions customized the heuristic and its associated data structure to rapidly compute the minimum-cut metric central to circuit partitioning; as such, those extensions are not directly applicable to other problems. In this paper, we extend the heuristic for functional partitioning, which in turn can solve the much investigated codesign problem of partitioning a system's coarse-grained functions among hardware and software components. The key extension customizes the heuristic and data structure to rapidly compute execution-time and communication metrics, crucial to hardware and software partitioning, and leads to near-linear time-complexity and excellent resulting quality. Another extension uses a new criteria for terminating the heuristic, eliminating time-consuming and unnecessary fine-tuning of a partition. Our experiments demonstrate extremely fast execution times (just a few seconds) with results matched only by the slower simulated annealing heuristic, meaning that the extended Kernighan/Lin heuristic will likely prove hard to beat for hardware and software functional partitioning. 相似文献
6.
François Treussart Nicolas Dubreuil Jongthan Cave Knight Vahid Sandoghdar Jean Hare Valçrie Lefçvre-Seguin Jean-Michel Raimond Serge Haroche 《电信纪事》1997,52(11-12):557-568
Light can be confined efficiently in the high-Q, small-volume whispering-gallery-modes observed in silica microspheres. By coupling these microspheres to eroded optical fibers and fiber tips, direct mapping of the whispering-gallery modes has been achieved and the mode numbers have been assessed. The properties of these modes have allowed us to obtain laser action with very low thresholds in Nd-doped silica microspheres. Further projects in the field of non-linear optics and cavity quantum electrodynamics are described. 相似文献
7.
Robinson J. Rubinov E. Toulson C. Prasada B. Sabri S. Goldberg N. Vonderweidt G. 《Communications, IEEE Transactions on》1991,39(11):1698-1708
The multimedia interactive conferencing application (MICA), a personal-workstation application for multipoint visual teleconferencing, is described. MICA allows people at two or more locations to share visual material such as documents, photographs, and computer screens in a highly interactive way. It supports the distribution, storage, retrieval, and high-quality display of visuals, real-time interaction by pointing and annotation, and meeting services facilities. The context of multimedia teleconferencing and computer-supported cooperative work is established, relating earlier research to the design of MICA. The services MICA offers are outlined. The handling, compression, and display of multiple media, and the design of a suitable user interface for MICA are discussed 相似文献
8.
Sabri Boughorbel Jean-Philippe Tarel Fran?ois Fleuret Nozha Boujemaa 《The Journal of supercomputing》1988,2(4):449-450
Contributing authors 相似文献
9.
Abstract. This article proposes an extension to scalar component methodology for the identification and estimation of VARMA models. The complete methodology determines the exact positions of all free parameters in any VARMA model with a predetermined embedded scalar component structure. This leads to an exactly identified system of equations that is estimated using full information maximum likelihood. 相似文献
10.
Vahid Garousi 《Software and Systems Modeling》2012,11(2):273-285
Technical books of each subject area denote the level of maturity and knowledge demand in that area. According to the Google
Books database, about 208 Unified Modeling Language (UML) books have been published from its inception in 1997 until 2009.
While various book reviews are frequently published in various sources (e.g., IEEE Software Bookshelf), there are no studies
to classify UML books into meaningful categories. Such a classification can help researchers in the area to identify trends
and also reveal the level of activity in each sub-area of UML. The statistical survey reported in this article intends to
be a first step in classification and trend analysis of the UML books published from 1997 to 2009. The study also sheds light
on the quantity of books published in different focus areas (e.g., UML’s core concepts, patterns, tool support, Object Constraint
Language and Model-Driven Architecture) and also on different application domains (e.g., database modeling, web applications,
and real-time systems). The trends of book publications in each sub-area of UML are also used to track the level of maturity,
to identify possible Hype cycles and also to measure knowledge demand in each area. 相似文献