全文获取类型
收费全文 | 14817篇 |
免费 | 1226篇 |
国内免费 | 573篇 |
专业分类
电工技术 | 744篇 |
技术理论 | 1篇 |
综合类 | 982篇 |
化学工业 | 2417篇 |
金属工艺 | 745篇 |
机械仪表 | 915篇 |
建筑科学 | 1445篇 |
矿业工程 | 433篇 |
能源动力 | 445篇 |
轻工业 | 849篇 |
水利工程 | 239篇 |
石油天然气 | 921篇 |
武器工业 | 74篇 |
无线电 | 1805篇 |
一般工业技术 | 1895篇 |
冶金工业 | 688篇 |
原子能技术 | 169篇 |
自动化技术 | 1849篇 |
出版年
2024年 | 42篇 |
2023年 | 215篇 |
2022年 | 368篇 |
2021年 | 618篇 |
2020年 | 455篇 |
2019年 | 350篇 |
2018年 | 400篇 |
2017年 | 477篇 |
2016年 | 395篇 |
2015年 | 553篇 |
2014年 | 689篇 |
2013年 | 932篇 |
2012年 | 897篇 |
2011年 | 952篇 |
2010年 | 885篇 |
2009年 | 805篇 |
2008年 | 848篇 |
2007年 | 755篇 |
2006年 | 800篇 |
2005年 | 729篇 |
2004年 | 470篇 |
2003年 | 433篇 |
2002年 | 467篇 |
2001年 | 385篇 |
2000年 | 410篇 |
1999年 | 427篇 |
1998年 | 342篇 |
1997年 | 284篇 |
1996年 | 271篇 |
1995年 | 230篇 |
1994年 | 187篇 |
1993年 | 118篇 |
1992年 | 100篇 |
1991年 | 103篇 |
1990年 | 65篇 |
1989年 | 49篇 |
1988年 | 28篇 |
1987年 | 23篇 |
1986年 | 13篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
161.
烟气脱硫技术在浮法玻璃线上的应用 总被引:1,自引:1,他引:1
简介了烟气脱硫技术在浮法玻璃线上的应用情况,以工程实例详细介绍该技术在某浮法玻璃线上的设计、实施、应用情况以及重点、难点问题的处理,为该技术在浮法玻璃线的应用提供借鉴和参考. 相似文献
162.
Maoguo Gong Meng Jia Linzhi Su Shuang Wang Licheng Jiao 《International journal of remote sensing》2014,35(11-12):4009-4030
The Yellow River Estuary area of China is under great pressure from both human intervention and natural processes. For analysis of the changes in this area, this article presents a novel change-detection method based on a local fit-search model and kernel-induced graph cuts in multitemporal synthetic aperture radar images. Change detection involves assigning a label to every pixel. This task is naturally formulated in terms of energy minimization, which can be effectively solved by graph cuts. The difference image is transformed implicitly by a kernel function so that an alternative to complex modelling of the original data makes the piecewise constant model become applicable for graph cuts formulation. An issue is that graph cuts are sensitive to the initial estimate. The local fit-search model is proposed to approximate to the local histogram while selecting an optimal threshold for the initial labelling, which leads to an effective constraint for graph cuts and computational benefits as well. Visual and quantitative analyses obtained on the Yellow River Estuary data set confirm the effectiveness of the proposed method and that it outperforms the other state-of-the-art methods of change detection. 相似文献
164.
165.
介绍了目前国内飞机蒙皮涂料的发展及存在的问题 ,分析讨论了性能优异的氟碳涂料在飞机蒙皮中应用的意义。 相似文献
166.
本文论述了目前国内外连续移动床炼焦新技术的工艺原理,介绍了国外连续移动床炼焦新技术的工艺流程及特性,并对连续移动床炼焦新技术的经济技术指标和焦炭特性进行了评述。 相似文献
167.
Sharks are the most dangerous predators of people in the sea, resulting in people being mauled and killed each year. A shark
repellent could help to diminish this danger. The aglycone of the shark repellent pavoninin-5, (25R)-cholest-5-en-3β,15α,26-triol (5a), was synthesized from diosgenin (9). Removing mercury from the Clemmensen reduction of 9 gave a higher yield of (25R)-cholest-5-en-3β,16β,26-triol, 10a, and was also more environmentally friendly. Attempted methods for the transposition of the C-16β hydroxyl to the 15α position
are described. A successful method for this transposition via the 15α-hydroxy-16-ketone, 8a, using the Barton deoxygenation reaction on the 16-alcohol 14b, is reported. 相似文献
168.
We give an up-to-date survey on techniques and methods for fire simulation in computer graphics. Physically-based method prevails over traditional non-physical methods for realistic visual effect. In this paper, we explore visual simulation of fire-related phenomena in terms of physically modeling, numerical simulation and visual rendering. Firstly, we introduce a physical and chemical coupled mathematical model to explain fire behavior and motion. Several assumptions and constrains are put forward to simplify their implementations in computer graphics. We then give an overview of present methods to solve the most complicated processes in numerical simulation: velocity advection and pressure projection. In addition, comparisons of these methods are also presented respectively. Since fire is a participating medium as well as a visual radiator, we discuss techniques and problems of these issues as well. We conclude by addressing several open challenges and possible future research directions in fire simulation. 相似文献
169.
A simple strategy was developed based on a new reactive function‐ and a salt‐containing new monomer, 4‐vinylbenzyl dimethyl 2‐(dimethylphosphino)ethyl phosphonium chloride (VDEPC), to obtain stable humidity‐sensitive membranes. The major ingredient of a humid membrane is crosslinked polyelectrolytes obtained from copolymers of VDEPC/2‐ethylhexyl acrylate (2‐EHA) = 1/0, 4/1, and 2/1. Isothermal humidity absorption experiments were performed for the estimation of humidity‐sensing materials. The crosslinked copolymers prepared from the reaction of VDEPC/2‐EHA = 4/1 with 1,4‐dichlorobutane showed an average impedance of 595, 39.1, and 3.9 KΩ at 30, 60, and 90% RH, respectively. Their hysteresis, temperature dependence, frequency dependence, and response time were measured. The reliability including water resistance and a long‐term stability were estimated for the application of the common humidity sensor. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1062–1070, 2003 相似文献
170.
聚苯乙烯纳米塑料研究进展 总被引:2,自引:0,他引:2
介绍了聚苯乙烯纳米塑料的制备方法,对聚苯乙烯纳米塑料的研究进展进行了综述。 相似文献