全文获取类型
收费全文 | 16683篇 |
免费 | 1343篇 |
国内免费 | 55篇 |
专业分类
电工技术 | 274篇 |
综合类 | 23篇 |
化学工业 | 3764篇 |
金属工艺 | 496篇 |
机械仪表 | 894篇 |
建筑科学 | 375篇 |
矿业工程 | 6篇 |
能源动力 | 690篇 |
轻工业 | 1390篇 |
水利工程 | 54篇 |
石油天然气 | 12篇 |
无线电 | 3073篇 |
一般工业技术 | 3524篇 |
冶金工业 | 1270篇 |
原子能技术 | 203篇 |
自动化技术 | 2033篇 |
出版年
2024年 | 20篇 |
2023年 | 177篇 |
2022年 | 283篇 |
2021年 | 473篇 |
2020年 | 340篇 |
2019年 | 440篇 |
2018年 | 550篇 |
2017年 | 504篇 |
2016年 | 644篇 |
2015年 | 549篇 |
2014年 | 767篇 |
2013年 | 1144篇 |
2012年 | 1028篇 |
2011年 | 1268篇 |
2010年 | 903篇 |
2009年 | 952篇 |
2008年 | 887篇 |
2007年 | 720篇 |
2006年 | 692篇 |
2005年 | 564篇 |
2004年 | 539篇 |
2003年 | 472篇 |
2002年 | 457篇 |
2001年 | 379篇 |
2000年 | 345篇 |
1999年 | 343篇 |
1998年 | 529篇 |
1997年 | 388篇 |
1996年 | 270篇 |
1995年 | 228篇 |
1994年 | 184篇 |
1993年 | 142篇 |
1992年 | 110篇 |
1991年 | 99篇 |
1990年 | 90篇 |
1989年 | 82篇 |
1988年 | 46篇 |
1987年 | 67篇 |
1986年 | 68篇 |
1985年 | 48篇 |
1984年 | 43篇 |
1983年 | 41篇 |
1982年 | 14篇 |
1981年 | 23篇 |
1980年 | 27篇 |
1979年 | 18篇 |
1978年 | 17篇 |
1977年 | 23篇 |
1976年 | 36篇 |
1975年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Joon‐Young Jun Sosuke Nakajima Koji Yamazaki Yuji Kawai Hajime Yasui Yasuyuki Konishi 《International Journal of Food Science & Technology》2015,50(4):871-877
Cystoseira hakodatensis is an unutilised brown algae belonging to family Sargassaceae. A crude methanol extract from the algae showed inhibitory effects on the growths of Bacillus cereus and Bacillus licheniformis. To isolate the major antimicrobial agent, a sequential active‐guided isolation procedure was applied: liquid–liquid extraction, column chromatography and bio‐autography. A marked antimicrobial agent (active α) was isolated in hydrophobic fraction and was determined to phenolics without carbohydrates and proteins by phytochemical test. Regarding the antimicrobial potential, the isolated active α showed better inhibitory effects against B. cereus and B. licheniformis at 2 and 4 times of lower concentrations (62.5 and 31.3 μg mL?1) in comparison with epigallocatechin gallate. These results showed that C. hakodatensis is a potential source of antimicrobial agent capable of preventing the growth of the two bacteria. 相似文献
6.
7.
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
8.
Honour Index (HoI), a method to evaluate research performance within different research fields, was derived from the impact
factor (IF). It can be used to rate and compare different categories of journals. HoI was used in this study to determine
the scientific productivity of stem cell research in the Asian Four Dragons (Hong Kong, Singapore, South Korea and Taiwan)
from 1981 to 2001. The methodology applied in this study represents a synthesis of universal indicator studies and bibliometric
analyses of subfields at the micro-level. We discuss several comparisons, and conclude the developmental trend in stem cell
research for two decades.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Data mining extracts implicit, previously unknown, and potentially useful information from databases. Many approaches have been proposed to extract information, and one of the most important ones is finding association rules. Although a large amount of research has been devoted to this subject, none of it finds association rules from directed acyclic graph (DAG) data. Without such a mining method, the hidden knowledge, if any, cannot be discovered from the databases storing DAG data such as family genealogy profiles, product structures, XML documents, task precedence relations, and course structures. In this article, we define a new kind of association rule in DAG databases called the predecessor–successor rule, where a node x is a predecessor of another node y if we can find a path in DAG where x appears before y. The predecessor–successor rules enable us to observe how the characteristics of the predecessors influence the successors. An approach containing four stages is proposed to discover the predecessor–successor rules. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 621–637, 2006. 相似文献
10.
Many organisations use decision models in their processes such as tables or trees to provide decision support to their operational
divisions. For example, in fault management, customer contact centre operators usually use a decision model in the form of
prescribed interviews. Based on the answers given by customers, the operator navigates through the decision model to reach
an assessment of the problem. In order to achieve customer satisfaction and operational excellence, it is very important to
constantly monitor the performance of a decision model not only on an overall level, but also on the level of individual decisions.
In this paper we present a configurable business process analytics tool, known as the intelligent Universal Service Management
System, that constantly monitors decision data and is capable of optimising the decisions based on high-level business objectives.
We explain the various features of the software and show how it can be used to optimise decision processes. We also show how
we can easily provide a customised version to monitor the performance of provision processes. 相似文献