全文获取类型
收费全文 | 1526篇 |
免费 | 71篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 32篇 |
综合类 | 4篇 |
化学工业 | 323篇 |
金属工艺 | 87篇 |
机械仪表 | 173篇 |
建筑科学 | 11篇 |
能源动力 | 33篇 |
轻工业 | 123篇 |
水利工程 | 1篇 |
无线电 | 196篇 |
一般工业技术 | 274篇 |
冶金工业 | 167篇 |
原子能技术 | 34篇 |
自动化技术 | 146篇 |
出版年
2023年 | 14篇 |
2022年 | 9篇 |
2021年 | 46篇 |
2020年 | 20篇 |
2019年 | 32篇 |
2018年 | 31篇 |
2017年 | 48篇 |
2016年 | 43篇 |
2015年 | 24篇 |
2014年 | 44篇 |
2013年 | 85篇 |
2012年 | 93篇 |
2011年 | 95篇 |
2010年 | 59篇 |
2009年 | 69篇 |
2008年 | 70篇 |
2007年 | 60篇 |
2006年 | 71篇 |
2005年 | 58篇 |
2004年 | 41篇 |
2003年 | 51篇 |
2002年 | 51篇 |
2001年 | 33篇 |
2000年 | 46篇 |
1999年 | 44篇 |
1998年 | 64篇 |
1997年 | 49篇 |
1996年 | 55篇 |
1995年 | 27篇 |
1994年 | 26篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 20篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1977年 | 12篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有1604条查询结果,搜索用时 15 毫秒
1.
Biodegradable multiblock poloxamers (BMPs) with gel duration of 8 h to several weeks were prepared by varying their molecular weights from 4000 to 40 000 g mol?1. The molecular weight of the BMP was controlled by changing the poloxamer to coupling agent ratio. Assuming a micelle packing model of the BMP gel, as in the case of a poloxamer gel, the micelle properties and critical gel concentration of BMPs were investigated on the basis of the scaling concept. The findings suggest that the control of molecular weight by hydrolyzable groups can be a facile approach to optimize the gel properties for biomedical applications. Copyright © 2005 Society of Chemical Industry 相似文献
2.
The ability to utilize fully automated flexible manufacturing systems (FMS) or develop reliable computer-integrated manufacturing (CIM) systems will depend on our ability to develop reliable and reusable software for large complex systems on a timely basis. To date, software design has not gone very far beyond the ad hoc trial-and-error stage. Consequently, the development of software is slow, expensive, unreliable, and unmanageable. The purpose of this paper is to provide a scientific basis for designing software. The approach used here is that of axiomatic design, which is based on two design axioms: the Independence Axiom and the Information Axiom. The axiomatic approach is based on the recognition of the following common elements in design: the existence of independent domains (i.e. the consumer domain, the functional domain, the physical domain, and the process domain); the need to map between various domains during the design process; the decomposition of the characteristic vectors (i.e. functional requirements, design parameters, and process variables) in their respective domains; the zig-zagging required between the domains for decomposition; and the need to satisfy the design axioms during the design process. The axiomatic approach discussed in this paper provides decision making tools for software design in addition to systematic means of knowledge and data representation, synthesis and analysis of software, and the construction of the module-junction structure diagram. 相似文献
3.
HJ Lee HK Ha MH Kim YK Jeong PN Kim MG Lee JS Kim DJ Suh SG Lee YI Min YH Auh 《Canadian Metallurgical Quarterly》1997,169(2):517-520
OBJECTIVE: The purpose of this study was to evaluate ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb. CONCLUSION: Although rare, the diagnosis of ectopic drainage of the common bile duct into the duodenal bulb is important to prevent inadvertent damage during biliary tract or gastric surgery and to clarify the cause of chronic peptic ulcers. 相似文献
4.
Microllular plastics are cellular polymers characterized by cell densities greater than 109 cells/cm3 and cells smaller than 10 μm. One of the critical steps in the continuous production of microcellular plastics is the promotion of high cell nucleation rates in a flowing polymer matrix. These high nucleation rates can be achieved by first forming a polymer/gas solution followed by rapidly decreasing the solubility of gas in the polymer. Since, in the processing range of interest, the gas solubility in the polymer decreases as the pressure decreases, a rapid pressure drop element, consisting of a nozzle, has been employed as a continuous microcellular nucleation device. In this paper, the effects of the pressure drop rate on the nucleation of cells and the cell density are discussed. The experimental results indicate that both the magnitude and the cell density are discussed. The experimental results indicate that both the magnitude and the rate of pressure drop play a strong role in microcellular processing. The pressure phenomenon affects the thermodynamic instability induced in the polymer/gas solution and the competition between cell nucleation and growth. 相似文献
5.
6.
7.
8.
Chang-Kyo Suh Eui-Ho Suh Kwang-Churn Baek 《Engineering Management, IEEE Transactions on》1994,41(3):264-275
This paper concerns telecommunications technologies prioritization for long-range R&D planning at the Korea Telecommunication Authority (KTA), which is the primary common carrier in Korea. Criteria weighting and technological importance ranking were determined by means of the Analytic Hierarchy Process as a decision aid, along with hierarchical representation and pairwise comparisons. The opinions derived from three divisions of KTA were analyzed and aggregated. Such aggregated prioritization weighting of technologies allows the corporation management to use it for funding decisions about technological aspects of its long-range planning for R&D projects during the period from 1992 to 2006; especially those concerning baseline budget level selection and the scope of research activities.<> 相似文献
9.
Hyun Kyu Suh 《Fuel》2008,87(6):925-932
This paper investigates the effect of injection parameters on the characteristics of dimethyl ether (DME) as an alternative fuel in a diesel engine with experimental and analytical models based on empirical equations. In order to study macroscopic and microscopic characteristics of DME fuel, this work focuses on the atomization characteristics of DME and compares experimental and predicted results for spray development obtained by empirical models for diesel and DME fuel. Detailed comparisons of spray tip penetration from three different empirical correlations and from visualization experiments of diesel and DME fuels were conducted under various fuel injection conditions. In comparison with the results of different empirical equations for measured spray tip penetration, the experimental results of this study provide good agreement with the calculation results based on empirical equations, except during the earliest stage of the injected spray sequence. The results of atomization characteristics indicate that DME showed better spray characteristics than conventional diesel fuel. Also, the fuel injection delay and maximum injection rate of DME fuel are shorter and lower than those of diesel fuel at the same injection conditions, respectively. 相似文献
10.