全文获取类型
收费全文 | 1174篇 |
免费 | 33篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 9篇 |
综合类 | 1篇 |
化学工业 | 160篇 |
金属工艺 | 11篇 |
机械仪表 | 27篇 |
建筑科学 | 92篇 |
矿业工程 | 8篇 |
能源动力 | 24篇 |
轻工业 | 94篇 |
水利工程 | 7篇 |
石油天然气 | 4篇 |
无线电 | 154篇 |
一般工业技术 | 170篇 |
冶金工业 | 133篇 |
原子能技术 | 7篇 |
自动化技术 | 308篇 |
出版年
2023年 | 6篇 |
2022年 | 11篇 |
2021年 | 34篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 25篇 |
2017年 | 32篇 |
2016年 | 35篇 |
2015年 | 21篇 |
2014年 | 25篇 |
2013年 | 76篇 |
2012年 | 74篇 |
2011年 | 84篇 |
2010年 | 60篇 |
2009年 | 67篇 |
2008年 | 72篇 |
2007年 | 70篇 |
2006年 | 59篇 |
2005年 | 47篇 |
2004年 | 38篇 |
2003年 | 24篇 |
2002年 | 40篇 |
2001年 | 21篇 |
2000年 | 18篇 |
1999年 | 18篇 |
1998年 | 43篇 |
1997年 | 27篇 |
1996年 | 17篇 |
1995年 | 15篇 |
1994年 | 13篇 |
1993年 | 7篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1985年 | 6篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 4篇 |
1965年 | 2篇 |
排序方式: 共有1209条查询结果,搜索用时 0 毫秒
1.
2.
3.
N. E. Wijeysundera M. N. A. Hawlader Chan Wee Boon Andy M. Kamal Hossain 《International Journal of Refrigeration》2004,27(5):1997
An ice slurry generation system was developed using direct contact heat transfer between water and the coolant, Fluroinert FC-84. The location of the coolant nozzle is an important design consideration to avoid clogging due to freezing of water. An ice fraction of up to about 40 percent was obtained with the nozzle located at the bottom of the ice slurry tank and the jet directed upwards into the water. Two simplified model were developed to extract the heat transfer coefficient between the coolant drops and the water. The first model requires as input the average drop diameter and the residence time while the second model uses the measured drop diameter distribution. The estimated heat transfer coefficients are much smaller than those computed using single-sphere correlations. 相似文献
4.
Ohtsu M. Liou K.-Y. Burrows E.C. Burrus C.A. Eisenstein G. 《Electronics letters》1987,23(21):1111-1113
A problem in frequency-tuning of external-cavity lasers is mode-hopping between neighbouring external-cavity modes. We demonstrate a new interferometric method for monitoring mode-hoping and an automatic control circuit for a 1.3 ?m grating external-cavity laser that maintains single-mode operation when the lasing frequency is tuned. 相似文献
5.
This article describes the operation of two new tests of authorshipand offers some results. Both tests rely on controlled contrastsof word-frequency and both exclude the very common words, whichhave been put to such good use in recent years. One test treatsof words used with some consistency by a target-author but moresporadically by others. The second treats of words used sporadicallyby the target-author but not by most others. (The inclusionof words that some other authors use avoids the strict constraintthat has impoverished this form of evidence.) In suitable cases,both tests prove very accurate. The fact that evidence of authorshipcan be detected in these three distinct frequency-strata helpsto explain why such tests should work at all and so encouragesthe development of even better ones. 相似文献
6.
7.
Les Hatton Andy Wright Stuart Smith Gregg Parkes Paddy Bennett Robert Laws 《Software》1988,18(4):301-329
The portability of software has become a major commercial issue in recent times. Such portability does not come easily, as few if any computer languages are really portable in practice. An additional complicating factor, especially in the commercial environment, is that the resulting software must be efficient. This paper describes the design and successful implementation of a 500,000+ line portable FORTRAN 77 package for the processing of seismic data. The package exhibits demonstrably high efficiency on a wide variety of machines from minicomputers to the largest supercomputers. Experiences gained during this exercise throw much light on the integration of the various thought processes which occur during the software engineering cycle, especially the notion of locality. 相似文献
8.
9.
The experimental determination and computer simulation of the micro‐segregation accompanying the solidification of alloys continues to be a subject of much academic and industrial interest. Both are subject to progressively more sophisticated analyses, and a discussion is offered regarding the development and practical use of such studies. Simple steels are particularly difficult targets for such work: solidification does not end conveniently in a eutectic, the rapid diffusion particularly in the delta‐ferrite phase obscures most evidence of what had occurred at the micro‐scale during solidification, and one or more subsequent solid state phase transformations further obscure such details. Also, solidification at the micro‐scale is inherently variable: the usual, dendrite morphologies encountered are, after all, instabilities in growth behaviour, and therefore such variability should be expected. For questions such as the relative susceptibility of different grades to particular problems, it is the average, typical behaviour that is of interest, whereas for other questions such as the on‐set of macro‐segregation, the local variability is paramount. Depending on the question being asked, and indeed the accuracy with which validatory data are available, simple pseudo‐analytical equations employing various limiting assumptions, or sophisticated models which remove the need for most such limitations, could be appropriate. This paper highlights the contribution to such studies of various collaborative research forums with‐in the European Union with which the author is involved. 相似文献
10.