全文获取类型
收费全文 | 576741篇 |
免费 | 8019篇 |
国内免费 | 1010篇 |
专业分类
电工技术 | 10575篇 |
综合类 | 474篇 |
化学工业 | 94452篇 |
金属工艺 | 23449篇 |
机械仪表 | 18762篇 |
建筑科学 | 12930篇 |
矿业工程 | 4328篇 |
能源动力 | 14703篇 |
轻工业 | 48518篇 |
水利工程 | 7029篇 |
石油天然气 | 15022篇 |
武器工业 | 39篇 |
无线电 | 60666篇 |
一般工业技术 | 117643篇 |
冶金工业 | 95954篇 |
原子能技术 | 14708篇 |
自动化技术 | 46518篇 |
出版年
2022年 | 4539篇 |
2021年 | 6387篇 |
2020年 | 4364篇 |
2019年 | 5637篇 |
2018年 | 9619篇 |
2017年 | 9844篇 |
2016年 | 10316篇 |
2015年 | 6423篇 |
2014年 | 10756篇 |
2013年 | 26871篇 |
2012年 | 16490篇 |
2011年 | 21897篇 |
2010年 | 17578篇 |
2009年 | 19388篇 |
2008年 | 19586篇 |
2007年 | 19248篇 |
2006年 | 16670篇 |
2005年 | 15023篇 |
2004年 | 14248篇 |
2003年 | 13905篇 |
2002年 | 13444篇 |
2001年 | 12967篇 |
2000年 | 12407篇 |
1999年 | 12123篇 |
1998年 | 27727篇 |
1997年 | 20113篇 |
1996年 | 15711篇 |
1995年 | 12056篇 |
1994年 | 10905篇 |
1993年 | 10659篇 |
1992年 | 8389篇 |
1991年 | 8143篇 |
1990年 | 8021篇 |
1989年 | 7787篇 |
1988年 | 7506篇 |
1987年 | 6771篇 |
1986年 | 6565篇 |
1985年 | 7423篇 |
1984年 | 6722篇 |
1983年 | 6457篇 |
1982年 | 5789篇 |
1981年 | 5912篇 |
1980年 | 5649篇 |
1979年 | 5747篇 |
1978年 | 5680篇 |
1977年 | 6186篇 |
1976年 | 7691篇 |
1975年 | 5117篇 |
1974年 | 4904篇 |
1973年 | 4983篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Semiconductors - In this work, we discuss for the first time the principle of rotation in the constant electric field of a conducting particle with participation of the Lorentz force, which ensures... 相似文献
4.
Atomic Energy - The history and direction of further development of space nuclear energetics are examined. The functional diagram and principle of operation of a promising, powerful,... 相似文献
5.
Bernette Maria Oosterlaken Heiner Friedrich Gijsbertus de With 《Microscopy research and technique》2022,85(1):412-417
Transmission electron microscopy (TEM) is an important analysis technique to visualize (bio)macromolecules and their assemblies, including collagen fibers. Many protocols for TEM sample preparation of collagen involve one or more washing steps to remove excess salts from the dispersion that could hamper analysis when dried on a TEM grid. Such protocols are not standardized and washing times as well as washing solvents vary from procedure to procedure, with each research group typically having their own protocol. Here, we investigate the influence of washing with water, ethanol, but also methanol and 2-propanol, for both mineralized and unmineralized collagen samples via a protocol based on centrifugation. Washing with water maintains the hydrated collagen structure and the characteristic banding pattern can be clearly observed. Conversely, washing with ethanol results in dehydration of the fibrils, often leading to aggregation of the fibers and a less obvious banding pattern, already within 1 min of ethanol exposure. As we show, this process is fully reversible. Similar observations were made for methanol and propanol. Based on these results, a standardized washing protocol for collagenous samples is proposed. 相似文献
6.
Journal of Computer and Systems Sciences International - It is shown that the Lyapunov theorem on the distribution properties of the sum of random variables with different distribution densities... 相似文献
7.
Kuznetsov Yu. A. Markov M. A. Kravchenko I. N. Krasikov A. V. Bykova A. D. 《Refractories and Industrial Ceramics》2021,62(4):421-425
Refractories and Industrial Ceramics - The paper introduces a promising technology for utilizing a traditional scheme for implementing a flow-through micro-arc oxidation method to restore localized... 相似文献
8.
Chumakov Yu. A. Knyazeva A. G. Pribytkov G. A. 《Theoretical Foundations of Chemical Engineering》2021,55(3):490-503
Theoretical Foundations of Chemical Engineering - On the basis of the classic concepts of the theory of solid-phase combustion, for the first time, a model with a detailed scheme of chemical... 相似文献
9.
Deepika M. Malini Raajan N. R. Srinivasan A. 《Multimedia Tools and Applications》2022,81(9):12701-12724
Multimedia Tools and Applications - The three-dimensional models of brain tumors serve as diagnostic assistance for physicians, surgeons, and radiologists. The proposed system establishes an... 相似文献
10.
Journal of Chemical Ecology - Biocontrol agents such as parasitic wasps use long-range volatiles and host-associated cues from lower trophic levels to find their hosts. However, this chemical... 相似文献