全文获取类型
收费全文 | 4935篇 |
免费 | 874篇 |
国内免费 | 701篇 |
专业分类
电工技术 | 176篇 |
综合类 | 552篇 |
化学工业 | 695篇 |
金属工艺 | 716篇 |
机械仪表 | 147篇 |
建筑科学 | 68篇 |
矿业工程 | 59篇 |
能源动力 | 139篇 |
轻工业 | 151篇 |
水利工程 | 37篇 |
石油天然气 | 150篇 |
武器工业 | 52篇 |
无线电 | 849篇 |
一般工业技术 | 669篇 |
冶金工业 | 186篇 |
原子能技术 | 70篇 |
自动化技术 | 1794篇 |
出版年
2024年 | 23篇 |
2023年 | 108篇 |
2022年 | 180篇 |
2021年 | 211篇 |
2020年 | 242篇 |
2019年 | 216篇 |
2018年 | 154篇 |
2017年 | 226篇 |
2016年 | 229篇 |
2015年 | 244篇 |
2014年 | 321篇 |
2013年 | 367篇 |
2012年 | 401篇 |
2011年 | 376篇 |
2010年 | 289篇 |
2009年 | 318篇 |
2008年 | 285篇 |
2007年 | 322篇 |
2006年 | 276篇 |
2005年 | 251篇 |
2004年 | 170篇 |
2003年 | 168篇 |
2002年 | 141篇 |
2001年 | 148篇 |
2000年 | 113篇 |
1999年 | 112篇 |
1998年 | 73篇 |
1997年 | 90篇 |
1996年 | 83篇 |
1995年 | 56篇 |
1994年 | 51篇 |
1993年 | 44篇 |
1992年 | 37篇 |
1991年 | 24篇 |
1990年 | 31篇 |
1989年 | 19篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1977年 | 3篇 |
1975年 | 6篇 |
1973年 | 4篇 |
1951年 | 3篇 |
排序方式: 共有6510条查询结果,搜索用时 15 毫秒
21.
A generalized diffusion coefficient correlation for a binary system of liquids has been developed to represent the data for a wide range of temperatures. Detailed analysis shows that the proposed correlation fits the experimental measurements of diffusivity with the corresponding calculated values with an acceptable percentage error. 相似文献
22.
原始组织及加热方式对Al-5.8wt%Cu合金熔化行为的影响 总被引:3,自引:0,他引:3
利用DSC分析手段,研究了具有3种不同凝固组织的Al-5.8wt%合金在7种不同加热方式下的熔化开始温度和熔化热,发现凝固组织中存在的非平衡共晶在加热过程中大部分扩散溶解,溶入基体,剩余部分参与共晶熔化,其熔化开始温度与组织状态无关,随加热速度的增大略有升高,溶解部分的体积分散与组织状态和加热方式有关,随加热时间和非平衡相表面积的增大而增大。 相似文献
23.
Tao Li 《Machine Learning》2006,62(3):199-215
Clustering is the problem of identifying the distribution of patterns and intrinsic correlations in large data sets by partitioning
the data points into similarity classes. This paper studies the problem of clustering binary data. Binary data have been occupying
a special place in the domain of data analysis. A unified view of binary data clustering is presented by examining the connections
among various clustering criteria. Experimental studies are conducted to empirically verify the relationships. 相似文献
24.
25.
An 8-valued commutative ring is developed to process colored images. Algebraic operators are defined to perform a number of operations such as the extraction of the primary colors and contours of different colors. 相似文献
26.
27.
形态学边缘检测的新算法及其应用 总被引:3,自引:0,他引:3
刘岚岚 《红外与毫米波学报》1998,17(5):386-390
提出了一种基于数学形态学的边缘检测的所算法,该算法具有简便和灵活可编程控制等优点,比原来主算法更国完善,在实际应用中有着很好的前景,并给出了实验结果。 相似文献
28.
The behavior during creep in shear of eutectic indium-tin joints on copper and nickel substrates was examined in order to
determine the effect of creep deformation on the microstructure of the alloy. Primary creep was absent in all the samples
tested. The stress exponent at 20° C was much higher for samples on nickel than for those on copper, indicating a different
creep deformation mechanism. Also, the microstructure within the indium-tin joints differed significantly with a change of
substrate. Samples with a nickel substrate showed a colony microstructure that was not observed in those with a copper substrate.
Thus, eutectic morphology is important in determining deformation mechanism during creep. The microstructure within the joints
in tested and untested regions of the samples was effectively the same. This is quite distinct from the behavior of eutectic
lead-tin observed in previous work. Lead-tin formed a recrystallized band of material along a region of concentrated shear
deformation. While the deformation pattern in the indium-tin samples appeared to be the same as for lead-tin, the microstructural
changes did not occur. This implies that the behavior observed in lead-tin is not universal to eutectic alloys. 相似文献
29.
An algorithm for reconstructing a binary array of size N sx N from its forest of quadtree representation is presented. The algorithm traverses each tree of the forest in preorder and maps each ‘black’ node into the spatial domain. The time complexity in mapping is O(log N × Bn + Bp), where Bn is the number of black nodes in the forest and Bp is the number of black pixels in the N × N array. The algorithm has been implemented on an Apple II. 相似文献
30.
Buffer overflow vulnerabilities are one of the most commonly and widely exploited security vulnerabilities in programs. Most existing solutions for avoiding buffer overflows are either inadequate, inefficient or incompatible with existing code. In this paper, we present a novel approach for transparent and efficient runtime protection against buffer overflows. The approach is implemented by two tools: Type Information Extractor and Depositor (TIED) and LibsafePlus. TIED is first used on a binary executable or shared library file to extract type information from the debugging information inserted in the file by the compiler and reinsert it in the file as a data structure available at runtime. LibsafePlus is a shared library that is preloaded when the program is run. LibsafePlus intercepts unsafe C library calls such as strcpy and uses the type information made available by TIED at runtime to determine whether it would be ‘safe’ to carry out the operation. With our simple design we are able to protect most applications with a performance overhead of less than 10%. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献