全文获取类型
收费全文 | 714篇 |
免费 | 39篇 |
国内免费 | 26篇 |
专业分类
电工技术 | 24篇 |
综合类 | 84篇 |
化学工业 | 179篇 |
金属工艺 | 13篇 |
机械仪表 | 14篇 |
建筑科学 | 26篇 |
矿业工程 | 9篇 |
能源动力 | 4篇 |
轻工业 | 36篇 |
水利工程 | 1篇 |
石油天然气 | 22篇 |
武器工业 | 2篇 |
无线电 | 46篇 |
一般工业技术 | 65篇 |
冶金工业 | 12篇 |
原子能技术 | 3篇 |
自动化技术 | 239篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 7篇 |
2020年 | 12篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 18篇 |
2015年 | 11篇 |
2014年 | 35篇 |
2013年 | 44篇 |
2012年 | 35篇 |
2011年 | 36篇 |
2010年 | 34篇 |
2009年 | 42篇 |
2008年 | 39篇 |
2007年 | 50篇 |
2006年 | 26篇 |
2005年 | 36篇 |
2004年 | 29篇 |
2003年 | 28篇 |
2002年 | 11篇 |
2001年 | 33篇 |
2000年 | 25篇 |
1999年 | 29篇 |
1998年 | 24篇 |
1997年 | 21篇 |
1996年 | 20篇 |
1995年 | 9篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 15篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有779条查询结果,搜索用时 15 毫秒
91.
基于多基地声纳的反潜巡逻机检查搜潜效能研究 总被引:1,自引:0,他引:1
为解决传统反潜巡逻机检查搜潜存在作用距离短、搜索盲区大、精度低和经济性差的缺点,提出基于多基地声纳的反潜巡逻机检查搜潜方法.根据反潜巡逻机先布设的多基地声纳阵得到潜艇初步定位坐标,以4种不同的方案补投被动浮标,并利用声波衰减原理和TOL算法分别通过Matlab进行多基地搜索概率和GDOP定位精度的仿真.仿真结果表明:同等条件下,反潜巡逻机进行等边三角形补投被动浮标情况下的多基地声纳检查搜潜方法具有高搜索概率和定位精度,并能使用较少的浮标形成一个有效的检查圈.该方法可应用于反潜巡逻机检查搜潜,对反潜作战具有一定的军事意义. 相似文献
92.
蒋艳杰 《华北电力大学学报(自然科学版)》2004,31(5):102-104
通过用一元小波的张量积构造多元小波基,给出其双曲部分和对混合光滑Sobolev类逼近的 Jackson及 Bernstein 型不等式估计。 相似文献
93.
Knowledge bases (KBs) about notable entities and their properties are an important asset in applications such as search, question answering and dialog. All popular KBs capture virtually only positive statements, and abstain from taking any stance on statements not stored in the KB. This paper makes the case for explicitly stating salient statements that do not hold. Negative statements are useful to overcome limitations of question answering systems that are mainly geared for positive questions; they can also contribute to informative summaries of entities. Due to the abundance of such invalid statements, any effort to compile them needs to address ranking by saliency. We present a statistical inference method for compiling and ranking negative statements, based on expectations from positive statements of related entities in peer groups. Experimental results, with a variety of datasets, show that the method can effectively discover notable negative statements, and extrinsic studies underline their usefulness for entity summarization. Datasets and code are released as resources for further research. 相似文献
94.
Three heterocyclic compounds namely 3-anilino-5-imino-4-phenyl-1, 2,4-thiadiazoline (AIPT), 3-anilino-5-imino-4-tolyl-1, 2,4-thiadiazoline (AITT), and 3-anilino-5-imino-4-chlorophenyl-1, 2,4-thiadiazoline (AICT) were synthesized and their influence on the inhibition of corrosion of mild steel in 1 M HCl and 0.5 M H2SO4 was investigated by weight loss and potentiodynamic polarization techniques. The values of activation energy and free energy of adsorption of these compounds were also calculated. Potentiodynamic polarization studies were carried out at room temperature, and showed that all the compounds were mixed type inhibitors causing blocking of active sites on the metal. The inhibition efficiency of the compounds was found to vary with concentration, temperature and immersion time. Good inhibition efficiency was evidenced in both acid solutions. The adsorption of the compounds on mild steel for both acids was found to obey the Langmuir adsorption isotherm. Electrochemical impedance spectroscopy was also used to investigate the mechanism of corrosion inhibition. 相似文献
95.
建设校内生产性实训基地的校企组合模式的比较研究 总被引:2,自引:1,他引:1
易顺明 《沙洲职业工学院学报》2009,12(4):36-39
校内生产性实训基地是高职院校开展技能型、实用性人才培养的重要教学基础资源。建设校内生产性实训基地,必然要实施产学研合作的校企组合模式。校企组合的方式与程度不同,形成了“企业主导型”、“企业管理型”和“校企融合型”等模式。本文通过讨论三个典型案例,对三种主要的校企组合模式进行分类比较研究。 相似文献
96.
Schiff bases are versatile compounds synthesized from the condensation of primary amino compounds with aldehydes or ketones. The high thermal of many Schiff base and their complexes were useful attributes for their application as catalysts in reactions involving at high temperatures. This thermal behavior of Schiff bases and their complexes was evaluated by TGA/DTG and DTA curves with mass losses related to dehydration and decomposition. This review summarizes the developments in the last decade for thermal analysis of Schiff bases. Therefore, synthesis of Schiff bases and their complexes are reviewed. 相似文献
97.
98.
M. Borges-Quintana M. A. Borges-Trenard P. Fitzpatrick E. Martínez-Moro 《Applicable Algebra in Engineering, Communication and Computing》2008,19(5):393-411
In this paper we introduce a binomial ideal derived from a binary linear code. We present some applications of a Gröbner basis of this ideal with respect to a total degree ordering. In the first application we give a decoding method for the code. In the second one, by associating the code with the set of cycles in a graph, we can solve the problem of finding all codewords of minimal length (minimal cycles in a graph), and show how to find a minimal cycle basis. Finally we discuss some results on the computation of the Gröbner basis. 相似文献
99.
校外生产实习是高校培养专门人才的一个重要环节。本文对目前校外生产实习基地建设中存在的问题进行了探讨,提出了加强校外实习基地建设的几点建议,以推动学校的教育教学改革。 相似文献
100.
Omran Ahmadi 《Applicable Algebra in Engineering, Communication and Computing》2007,18(4):391-396
In this paper we study the trace spectra of polynomial bases for over . Shparlinski showed that there exists a polynomial basis having O(log n) elements of trace one. Here we show that for every t ≤ n, there exists a polynomial basis having t + O(log n) elements of trace one. We also study consequences of our results to the existence of irreducible polynomials of certain
weights. 相似文献