全文获取类型
收费全文 | 517758篇 |
免费 | 6205篇 |
国内免费 | 1254篇 |
专业分类
电工技术 | 9903篇 |
综合类 | 659篇 |
化学工业 | 77360篇 |
金属工艺 | 23180篇 |
机械仪表 | 18616篇 |
建筑科学 | 11850篇 |
矿业工程 | 2897篇 |
能源动力 | 11299篇 |
轻工业 | 43857篇 |
水利工程 | 5554篇 |
石油天然气 | 9042篇 |
武器工业 | 98篇 |
无线电 | 59590篇 |
一般工业技术 | 101912篇 |
冶金工业 | 90261篇 |
原子能技术 | 10880篇 |
自动化技术 | 48259篇 |
出版年
2021年 | 3745篇 |
2019年 | 3652篇 |
2018年 | 12683篇 |
2017年 | 13140篇 |
2016年 | 10422篇 |
2015年 | 4583篇 |
2014年 | 7264篇 |
2013年 | 19867篇 |
2012年 | 13591篇 |
2011年 | 22273篇 |
2010年 | 18836篇 |
2009年 | 19280篇 |
2008年 | 20091篇 |
2007年 | 21822篇 |
2006年 | 13499篇 |
2005年 | 14834篇 |
2004年 | 13202篇 |
2003年 | 12660篇 |
2002年 | 11618篇 |
2001年 | 10998篇 |
2000年 | 10675篇 |
1999年 | 10588篇 |
1998年 | 24928篇 |
1997年 | 17751篇 |
1996年 | 13939篇 |
1995年 | 10865篇 |
1994年 | 9707篇 |
1993年 | 9480篇 |
1992年 | 7519篇 |
1991年 | 6998篇 |
1990年 | 6995篇 |
1989年 | 6663篇 |
1988年 | 6424篇 |
1987年 | 5612篇 |
1986年 | 5559篇 |
1985年 | 6421篇 |
1984年 | 6085篇 |
1983年 | 5484篇 |
1982年 | 5186篇 |
1981年 | 5376篇 |
1980年 | 5080篇 |
1979年 | 4905篇 |
1978年 | 4798篇 |
1977年 | 5479篇 |
1976年 | 6876篇 |
1975年 | 4338篇 |
1974年 | 4196篇 |
1973年 | 4341篇 |
1972年 | 3549篇 |
1971年 | 3295篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Bankov S. E. Vesnik M. V. Kravchenko V. F. 《Journal of Communications Technology and Electronics》2020,65(4):398-405
Journal of Communications Technology and Electronics - Abstract—The article presents a rigorous numerical solution, using the Wiener–Hopf method, to the problem of plane wave... 相似文献
62.
63.
64.
V. E. Gromov A. M. Glezer K. V. Morozov Yu. F. Ivanov K. V. Volkov 《Russian Metallurgy (Metally)》2015,2015(13):1094-1097
A layer-by-layer analysis of the structures, the phase compositions, and the defect substructures of differentially hardened rails has been carried by optical and transmission electron microscopy. It is found that the material volume of the rail head fillet is cooled faster than the volume located along the central axis. 相似文献
65.
ABSTRACTThis paper deals with asymptotic stabilisation of a class of nonlinear input-delayed systems via dynamic output feedback in the presence of disturbances. The proposed strategy has the structure of an observer-based control law, in which the observer estimates and predicts both the plant state and the external disturbance. A nominal delay value is assumed to be known and stability conditions in terms of linear matrix inequalities are derived for fast-varying delay uncertainties. Asymptotic stability is achieved if the disturbance or the time delay is constant. The controller design problem is also addressed and a numerical example with an unstable system is provided to illustrate the usefulness of the proposed strategy. 相似文献
66.
67.
68.
69.
Pasquale Stano Tereza Pereira de Souza Paolo Carrara Emiliano Altamura Erica D’Aguanno Margherita Caputo 《先进材料力学与结构力学》2015,22(9):748-759
Here we report some recent biophysical issues on the preparation of solute-filled lipid vesicles and their relevance to the construction of “synthetic cells.” First, we introduce the “semi-synthetic minimal cells” as the liposome-based cell-like systems, which contain a minimal number of biomolecules required to display simple and complex biological functions. Next, we focus on recent aspects related to the construction of synthetic cells. Emphasis is given to the interplay between the methods of synthetic cell preparation and the physics of solute encapsulation. We briefly introduce the notion of structural and compositional “diversity” in synthetic cell populations. 相似文献
70.
Effect of gums on viability and β‐galactosidase activity of Lactobacillus spp. in milk drink during refrigerated storage 下载免费PDF全文
Bernice D. Karlton‐Senaye Reza Tahergorabi Valerie L. Giddings Salam A. Ibrahim 《International Journal of Food Science & Technology》2015,50(1):32-40
The viability and β‐galactosidase activity of four Lactobacillus strains in milk drink containing gums during 28 days of refrigerated storage at 4 °C were assessed. The population of Lactobacillus rhamnosus GGB101 and Lactobacillus rhamnosus GGB103 were maintained, whereas the population of Lactobacillus reuteri DSM20016 and Lactobacillus reuteri SD2112 significantly decreased. The recommended level of 6 log CFU g?1 was exceeded for all tested trains throughout storage. The highest viable number of Lactobacillus rhamnosus GGB103 (8.76 ± 0.03 log CFU mL?1) was obtained in the product containing carrageenan–maltodextrin. The addition of guar–locust bean–carrageenan led to 20‐fold increase in the level of β‐galactosidase activity for L. rhamnosus GGB101 (1208 ± 2.12 Miller units mL?1) compared to the control (61 ± 2.83 Miller units mL?1). Our results suggested that gums could be added to milk to improve viability and enhance β‐galactosidase activity of Lactobacillus. 相似文献