全文获取类型
收费全文 | 6983篇 |
免费 | 353篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 87篇 |
综合类 | 14篇 |
化学工业 | 1701篇 |
金属工艺 | 168篇 |
机械仪表 | 135篇 |
建筑科学 | 441篇 |
矿业工程 | 32篇 |
能源动力 | 169篇 |
轻工业 | 579篇 |
水利工程 | 52篇 |
石油天然气 | 8篇 |
无线电 | 598篇 |
一般工业技术 | 1398篇 |
冶金工业 | 495篇 |
原子能技术 | 60篇 |
自动化技术 | 1405篇 |
出版年
2024年 | 12篇 |
2023年 | 106篇 |
2022年 | 152篇 |
2021年 | 245篇 |
2020年 | 166篇 |
2019年 | 137篇 |
2018年 | 206篇 |
2017年 | 192篇 |
2016年 | 265篇 |
2015年 | 261篇 |
2014年 | 323篇 |
2013年 | 450篇 |
2012年 | 410篇 |
2011年 | 511篇 |
2010年 | 388篇 |
2009年 | 385篇 |
2008年 | 383篇 |
2007年 | 350篇 |
2006年 | 278篇 |
2005年 | 254篇 |
2004年 | 192篇 |
2003年 | 170篇 |
2002年 | 154篇 |
2001年 | 103篇 |
2000年 | 98篇 |
1999年 | 92篇 |
1998年 | 155篇 |
1997年 | 97篇 |
1996年 | 94篇 |
1995年 | 84篇 |
1994年 | 70篇 |
1993年 | 69篇 |
1992年 | 35篇 |
1991年 | 30篇 |
1990年 | 25篇 |
1989年 | 33篇 |
1988年 | 27篇 |
1987年 | 23篇 |
1986年 | 21篇 |
1985年 | 20篇 |
1984年 | 34篇 |
1983年 | 22篇 |
1982年 | 17篇 |
1981年 | 14篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 20篇 |
1976年 | 26篇 |
1974年 | 13篇 |
排序方式: 共有7342条查询结果,搜索用时 9 毫秒
1.
2.
3.
Torsten Bohlin Stefan F. Graebe 《International Journal of Adaptive Control and Signal Processing》1995,9(6):465-490
Grey box identification refers to the practice of identifying dynamical systems in model structures exploiting partial prior information. This contribution reviews a method for stochastic grey box identification and surveys experiences and lessons of applying it to a number of industrial processes. Issues to be addressed include advantages and costs of introducing stochastics into the model, the question of what contribution must be expected from the model designer as opposed to what can be formalized in computer algorithms, and an outlook on future plans to resolve present shortcomings. 相似文献
4.
5.
M Abele-Horn C Wolff P Dressel A Zimmermann W Vahlensieck F Pfaff G Ruckdeschel 《Canadian Metallurgical Quarterly》1996,15(7):595-598
The efficiency of the polymerase chain reaction (PCR) was compared with that of culture for detection of Ureaplasma urealyticum and Mycoplasma hominis in 726 clinical specimens comprising 189 gynecological samples, 362 urological samples, and 175 samples from newborn infants. The sensitivity of PCR versus culture was 95% for both organisms, while the sensitivity of culture versus PCR was 91% for Ureaplasma urealyticum and 84% for Mycoplasma hominis. Furthermore, PCR tests were faster than culture tests, allowing the time to diagnosis to be reduced from two to five days to 24 h. 相似文献
6.
7.
8.
Stefan Kasapis 《International Journal of Food Science & Technology》2002,37(4):403-413
The structural properties of mixtures of pectin, oxidized starch and glucose syrup were investigated using small deformation dynamic oscillation. In the absence of added calcium, preparations of low methoxy pectin with glucose syrup formed viscous solutions, which remained crystal-free at subzero temperatures. Samples of oxidized starch and glucose syrup, on the other hand, exhibited solid-like behaviour because of the crystalline nature of the amylose-like helices. Mixtures of the two polysaccharides with the co-solute clearly showed phase inversion from liquid to solid-like behaviour with increasing amounts of starch in the formulation. The transformation was reflected in the textural properties of samples, which varied from thick solutions to firm gels. The viscoelasticity of the system was modified further by the introduction of high methoxy pectin. Preparations of high methoxy pectin and glucose syrup formed rubbery gels whose amorphous nature underwent a glass transition during cooling. 相似文献
9.
Studies on the influence of anthracene coal extracts on the carbonization process of medium- and high-rank coals were undertaken. Extracts from flame coal (Int. Class. 900) and gas-coking coal (Int. Class. 632) were used as additives. The blends prepared from the examined coals and the extracts exhibited better coking properties than the parent coals. The addition of extract to the coals gave an increase in the microstrength of the resultant cokes. The effects of co-carbonization of coking coals with extracts were increases in the size of the optical texture as well as in the degree of structural ordering of cokes. In the co-carbonization of semicoking coal with addition of coal extracts, a reduction in the size of the anisotropic units and a decrease in the crystallite height of cokes were observed. No modification of the basic anisotropy of coke from anthracite by coal extract was observed. With increasing extract content in anthracite/extract blends there was an increase in the degree of structural ordering of co-carbonization products. Extract addition was unable to modify the behaviour of fusinite. Based on the results of investigation of the influence of coal extracts on the carbonization of different-rank coals, a division of coals according to the modification of the optical texture of coke is given. 相似文献
10.