全文获取类型
收费全文 | 142766篇 |
免费 | 14149篇 |
国内免费 | 8760篇 |
专业分类
电工技术 | 10216篇 |
技术理论 | 6篇 |
综合类 | 11304篇 |
化学工业 | 21098篇 |
金属工艺 | 8638篇 |
机械仪表 | 9814篇 |
建筑科学 | 11690篇 |
矿业工程 | 4459篇 |
能源动力 | 4473篇 |
轻工业 | 9506篇 |
水利工程 | 3332篇 |
石油天然气 | 7714篇 |
武器工业 | 1620篇 |
无线电 | 17125篇 |
一般工业技术 | 15656篇 |
冶金工业 | 5821篇 |
原子能技术 | 2076篇 |
自动化技术 | 21127篇 |
出版年
2024年 | 615篇 |
2023年 | 1964篇 |
2022年 | 3810篇 |
2021年 | 5491篇 |
2020年 | 4125篇 |
2019年 | 3502篇 |
2018年 | 3794篇 |
2017年 | 4432篇 |
2016年 | 4111篇 |
2015年 | 5760篇 |
2014年 | 7428篇 |
2013年 | 8689篇 |
2012年 | 9955篇 |
2011年 | 11001篇 |
2010年 | 10101篇 |
2009年 | 9691篇 |
2008年 | 9787篇 |
2007年 | 9414篇 |
2006年 | 9072篇 |
2005年 | 7308篇 |
2004年 | 5389篇 |
2003年 | 4838篇 |
2002年 | 4998篇 |
2001年 | 4286篇 |
2000年 | 3368篇 |
1999年 | 2844篇 |
1998年 | 1858篇 |
1997年 | 1581篇 |
1996年 | 1442篇 |
1995年 | 1158篇 |
1994年 | 959篇 |
1993年 | 726篇 |
1992年 | 498篇 |
1991年 | 379篇 |
1990年 | 286篇 |
1989年 | 261篇 |
1988年 | 208篇 |
1987年 | 136篇 |
1986年 | 106篇 |
1985年 | 54篇 |
1984年 | 45篇 |
1983年 | 44篇 |
1982年 | 40篇 |
1981年 | 32篇 |
1980年 | 24篇 |
1979年 | 18篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1959年 | 17篇 |
1951年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Linlin Zhu Liyuan Zhang Xi Li Xiaoqi Jin Tiejun Shi 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(7):551-560
AbstractGraphene oxide (GO) was functionalized by polyether amine (PEA) via two methods which were one-pot modification in acetone (GON) and two steps with the intermediate product of GOCO-Cl generated (GONS). There were more PEA successfully grafted onto GO for GONS than GON. The onset polymerization temperatures of the benzoxazine (Bz) composites decreased by the inclusion of 1?wt% of GO, GON or GONS. Thermal stability of the polybenzoxazine (PBz) composites was significantly improved indicated from the increase of weight loss temperature. T10, T20 and T50 values of the composites with GONS were higher than that of the others. Toughness of PBzs may be enhanced by the incorporation of nanofillers, and GONS had stronger interfacial interaction with PBz matrix than GON. 相似文献
95.
96.
结构的安全性是结构防止破坏倒塌的能力,是结构工程重要的质量指标.老工业基地中的厂房主体结构安全性评价,对于厂房加固改造起到了关键性作用.文中通过对某工业厂房主体结构大量现场勘验、隐患排查及检测数据,结合结构验算,从承载能力、损伤等几方面对该老旧工业厂房的安全性进行了评价与分析,并详细介绍了检测鉴定的流程,为以后类似的老旧工业厂房的检测鉴定提供参考. 相似文献
97.
The flame front deformation instability of low-velocity filtration combustion within an inert packed bed is studied based on the initial preheating non-uniformity. Based on the experimental phenomena, an initial thermal perturbation model is numerically proposed so as to predict the deformation behaviors of the flame front instabilities. The numerical prediction indicates that the assumption of an initial thermal perturbation is a feasible explanation as the cause of the flame front inclination instability. As the initial thermal perturbation increases, the phenomena of the flame front break and shrinking instabilities could easily occur at high filtration velocity or low equivalence ratio. Moreover, the evolutions of the flame front break rate and the shrinking rate are quantitatively analyzed. 相似文献
99.
100.
Frequency Insertion Strategy for Channel Assignment Problem 总被引:1,自引:0,他引:1
This paper presents a new heuristic method for quickly finding a good feasible solution to the channel assignment problem
(CAP). Like many other greedy-type heuristics for CAP, the proposed method also assigns a frequency to a call, one at a time.
Hence, the method requires computational time that increases only linear to the number of calls. However, what distinguishes
the method from others is that it starts with a narrow enough frequency band so as to provoke violations of constraints that
we need to comply with in order to avoid radio interference. Each violation is then resolved by inserting frequencies at the
most appropriate positions so that the band of frequencies expands minimally. An extensive computational experiment using
a set of randomly generated problems as well as the Philadelphia benchmark instances shows that the proposed method perform
statistically better than existing methods of its kind and even yields optimum solutions to most of Philadelphia benchmark
instances among which two cases are reported for the first time ever, in this paper.
Won-Young Shin was born in Busan, Korea in 1978. He received B.S. in industrial engineering from Pohang University of Science and Technology
(POSTECH) in 2001 and M.S in operation research and applied statistics from POSTECH in 2003. Since 2003 he has been a researcher
of Agency for Defense Development (ADD) in Korea. He is interested in optimization of communication system and applied statistics.
Soo Y. Chang is an associate professor in the Department of Industrial Engineering at Pohang University of Science and Technology (POSTECH),
Pohang, Korea. He teaches linear programming, discrete optimization, network flows and operations research courses. His research
interests include mathematical programming and scheduling. He has published in several journals including Discrete Applied
Mathematics, Computers and Mathematics with Application, IIE Transactions, International Journal of Production Research, and
so on. He is a member of Korean IIE, and ORMSS.
Jaewook Lee is an assistant professor in the Department of Industrial Engineering at Pohang University of Science and Technology (POSTECH),
Pohang, Korea. He received the B.S. degree in mathematics with honors from Seoul National University, and the Ph.D. degree
from Cornell University in applied mathematics in 1993 and 1999, respectively. He is currently an assistant professor in the
department of industrial engineering at the Pohang University of Science and Technology (POSTECH). His research interests
include nonlinear systems, neural networks, nonlinear optimization, and their applications to data mining and financial engineering.
Chi-Hyuck Jun was born in Seoul, Korea in 1954. He received B.S. in mineral and petroleum engineering from Seoul National University in
1977, M.S. in industrial engineering from Korea Advanced Institute of Science and Technology in 1979 and Ph.D. in operations
research from University of California, Berkeley, in 1986. Since 1987 he has been with the department of industrial engineering,
Pohang University of Science and Technology (POSTECH) and he is now a professor and the department head. He is interested
in performance analysis of communication and production systems. He has published in several journals including IIE Transactions,
IEEE Transactions, Queueing Systems and Chemometrics and Intelligent Laboratory Systems. He is a member of IEEE, INFORMS and
ASQ. 相似文献