全文获取类型
收费全文 | 26421篇 |
免费 | 671篇 |
国内免费 | 27篇 |
专业分类
电工技术 | 282篇 |
综合类 | 21篇 |
化学工业 | 5206篇 |
金属工艺 | 605篇 |
机械仪表 | 485篇 |
建筑科学 | 1093篇 |
矿业工程 | 95篇 |
能源动力 | 635篇 |
轻工业 | 1917篇 |
水利工程 | 301篇 |
石油天然气 | 225篇 |
武器工业 | 1篇 |
无线电 | 2071篇 |
一般工业技术 | 4135篇 |
冶金工业 | 6293篇 |
原子能技术 | 226篇 |
自动化技术 | 3528篇 |
出版年
2022年 | 172篇 |
2021年 | 279篇 |
2020年 | 240篇 |
2019年 | 310篇 |
2018年 | 351篇 |
2017年 | 360篇 |
2016年 | 438篇 |
2015年 | 341篇 |
2014年 | 518篇 |
2013年 | 1468篇 |
2012年 | 856篇 |
2011年 | 1105篇 |
2010年 | 872篇 |
2009年 | 891篇 |
2008年 | 1033篇 |
2007年 | 1099篇 |
2006年 | 910篇 |
2005年 | 853篇 |
2004年 | 797篇 |
2003年 | 749篇 |
2002年 | 705篇 |
2001年 | 486篇 |
2000年 | 477篇 |
1999年 | 505篇 |
1998年 | 954篇 |
1997年 | 695篇 |
1996年 | 583篇 |
1995年 | 511篇 |
1994年 | 468篇 |
1993年 | 522篇 |
1992年 | 407篇 |
1991年 | 317篇 |
1990年 | 368篇 |
1989年 | 356篇 |
1988年 | 335篇 |
1987年 | 330篇 |
1986年 | 358篇 |
1985年 | 379篇 |
1984年 | 362篇 |
1983年 | 362篇 |
1982年 | 303篇 |
1981年 | 322篇 |
1980年 | 304篇 |
1979年 | 306篇 |
1978年 | 280篇 |
1977年 | 301篇 |
1976年 | 343篇 |
1975年 | 241篇 |
1974年 | 214篇 |
1973年 | 215篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
In this article, we describe a new approach to applying distributed artificial intelligence techniques to manufacturing processes. The construction of intelligent systems is one of the most important techniques among artificial intelligence research. Our goal is to develop an integrated intelligent system for real time manufacturing processes. An integrated intelligent system is a large knowledge integration environment that consists of several symbolic reasoning systems (expert systems) and numerical computation packages. These software programs are controlled by a meta-system which manages the selection, operation and communication of these programs. A meta-system can be implemented in different language environments and applied to many disciplines. This new architecture can serve as a universal configuration to develop high performance intelligent systems for many complicated industrial applications in real world domains.To whom all correspondence should be addressed. 相似文献
13.
14.
D. A. Morgan D. B. Shaw M. J. Sidebottom T. C. Soon R. S. Taylor 《Journal of the American Oil Chemists' Society》1985,62(2):292-299
The results presented in the literature, which attempt to elucidate the mechanisms by which triglyceride oils are bleached
by earths, are reviewed. The impact of this work and how the mechanistic proposals affect changes in oil properties are considered,
with particular emphasis on the needs of the palm oil processor. Important properties include color, metals and phosphorus
content and oxidative stability of the oil.
Investigations made in our own laboratories have been aimed at elucidating the effect of varying physical and chemical properties
of the bleaching earth on the quality of bleached and deodorized oils. Techniques used in this work are pore-size distribution,
surface area, scanning and transmission electron microscopy and a variety of chemical and X-ray analysis methods.
The ability to vary such parameters in montmorillonite clays by alteration of process conditions to give materials with specific
performance characteristics is demonstrated.
Comparisons are made between acid-activated montmorillonites and other clay types. 相似文献
15.
Graduates of clinical training programs were surveyed to determine the degree to which they have found various graduate school experiences useful in their professional work. Samples of academic clinical psychologists and practicing clinical psychologists reported time allocation and preference for various professional activities, perceived usefulness of various theoretical orientations, and the influence on their current professional work of 19 different graduate training topics. Results suggest that where differences exist, academic clinical psychologists are generally more satisfied with Boulder-model-inspired scientific training than are clinical practitioners. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
16.
17.
18.
Digant Gupta Christopher G Lis Sadie L Dahlk Jessica King Pankaj G Vashi James F Grutsch Carolyn A Lammersfeld 《Nutrition journal》2008,7(1):19
Background
Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer. 相似文献19.
The thermal properties of a magnesium aluminium silicate (MAS) glass ceramic matrix composite reinforced by SiC (Nicalon)
fibres have been investigated before and after heat treatment in the temperature range 600–1,200 °C. Within this temperature
range, during the heat treatment at lower temperatures such as 600 and 700 °C, the oxidation of the carbon layer occurred
and mixture of silicon and carbon was formed in the interface. This results in a decrease in thermal diffusivity values. After
heat treatment at the temperatures higher than 1,000 °C, the carbon layer was thickened and resulted in the higher thermal
diffusivity values. 相似文献
20.
Power distribution systems have been significantly affected by many outage-causing events. Good fault cause identification can help expedite the restoration procedure and improve the system reliability. However, the data imbalance issue in many real-world data sets often degrades the fault cause identification performance. In this paper, the E-algorithm, which is extended from the fuzzy classification algorithm by Ishibuchi to alleviate the effect of imbalanced data constitution, is applied to Duke Energy outage data for distribution fault cause identification. Three major outage causes (tree, animal, and lightning) are used as prototypes. The performance of E-algorithm on real-world imbalanced data is compared with artificial neural network. The results show that the E-algorithm can greatly improve the performance when the data are imbalanced 相似文献