全文获取类型
收费全文 | 888篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 20篇 |
化学工业 | 183篇 |
金属工艺 | 9篇 |
机械仪表 | 18篇 |
建筑科学 | 59篇 |
矿业工程 | 14篇 |
能源动力 | 33篇 |
轻工业 | 84篇 |
水利工程 | 5篇 |
石油天然气 | 4篇 |
无线电 | 49篇 |
一般工业技术 | 62篇 |
冶金工业 | 264篇 |
原子能技术 | 8篇 |
自动化技术 | 92篇 |
出版年
2022年 | 12篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 19篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 23篇 |
2013年 | 57篇 |
2012年 | 26篇 |
2011年 | 28篇 |
2010年 | 25篇 |
2009年 | 19篇 |
2008年 | 31篇 |
2007年 | 26篇 |
2006年 | 22篇 |
2005年 | 29篇 |
2004年 | 14篇 |
2003年 | 18篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 16篇 |
1999年 | 24篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1996年 | 12篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1991年 | 13篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1982年 | 9篇 |
1981年 | 14篇 |
1980年 | 20篇 |
1979年 | 17篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 14篇 |
1974年 | 15篇 |
1973年 | 8篇 |
1964年 | 7篇 |
1957年 | 9篇 |
1956年 | 7篇 |
排序方式: 共有904条查询结果,搜索用时 15 毫秒
111.
Ernest L. McDuffieMoti SchneiderFrederick B. BuoniEliahu ShnaiderMelech Schneider Engineering ConsultantLouis A. Martin-Vega 《Engineering Applications of Artificial Intelligence》1995,8(6):681
In this paper the concept of recursive Allen temporal algebra is fully described, along with its relationship to the smart scheduler program and the concept of smart scheduling in general. Flexible manufacturing systems (FMS) are described, and their relationship with smart scheduling is explored. A case study that shows the utility of SSP in an FMS environment is presented in detail. Conclusions about the concept of smart scheduling are presented in closing. 相似文献
112.
Describes the testing of an active-alert induction procedure which sufficiently controlled conditions to permit a comparison between the alterations produced by that procedure and those produced by the traditional relaxation induction technique. Ss were 50 university students. In the active-alert induction the S rode a bicycle ergometer under load, keeping eyes open while exercising and receiving suggestions of alertness. The alternate form, used in random alternation with the same Ss, consisted of the standard eye-fixation and relaxation induction of the Stanford Hypnotic Susceptibility Scale, Form B (SHSS-B). Within each session on 2 days during which each S served, the induction procedure was followed by 8 tests of responses to suggestion, from the SHSS-A and SHSS-B. The mean measured hypnotic responsiveness was independent of the type of induction. The active-alert condition was characterized by an acceleration of the rate of pedaling for the more responsive Ss. Although the subjective alterations differed between the 2 kinds of induction, the highly susceptible reported that in both cases altered states were achieved. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
113.
Reviews the book, Psychotherapy with older adults by Bob Knight (see record 1987-97045-000). The techniques of providing psychotherapy to older adults are the main topics of this trenchant text. There are several case examples throughout the book that illustrate the process of psychotherapy with the elderly. Knight has provided a much-needed, readable introduction and how-to instructions on psychotherapeutic service provision to this burgeoning segment of the population. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
114.
Responds to the paper by T. A. Cleary et al (see record 1976-03505-001) on the use of standardized tests with minorities and notes substantial shortcomings in the article. These include (1) lack of response to the key arguments of many critics of extant testing, (2) lack of recommendations for improving test development, and (3) placement of blame for bad testing on the practitioner. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
115.
116.
Ernest Levine Ira Greenhut Harold Margolin 《Metallurgical and Materials Transactions B》1973,4(11):2519-2525
Methods of revealing grain size in a two-phase α-β titanium alloy have been examined and observations on beta grain growth
in the presence of alpha have been carried out. The technique proposed by Greenfield and Margolin1 for revealing β matrix grain sizes has been shown not to produce grain growth. However, for grain sizes of about 10 μm the
G.M. technique does not reveal all the grains because of the similarity in orientation in neighboring grains. These clusters
of similarly oriented grains are shown to persist as grain growth takes place but the misorientation between grains within
a cluster decreases. Both the beta grain growth and alpha particle coarsening follow the same time dependency from which it
is shown that a linear relationship exists between α particle size and β grain size. It is proposed that α particles must
dissolve from theβ grain edges for β grain growth to occur. The linear dependency between beta grain size,D
β, and alpha particle size,d
α, can be rationalized either on the basis of geometrical or surface tension considerations.
Formerly with New York University.
Formerly Graduate Student with New York University. 相似文献
117.
118.
Microfluidic and nanofluidic technologies have long sought a fast, reliable method to overcome the creative limitations of planar fabrication methods, the resolution limits of lithography, and the materials limitations for fast prototyping. In the present work, we demonstrate direct 3D machining of submicrometer diameter, subsurface fluidic channels in glass, via optical breakdown near critical intensity, using a femtosecond pulsed laser. No postexposure etching or bonding is required; the channel network (or almost any arbitrary-shaped cavity below the surface) is produced directly from "art-to-part". The key to this approach is to use very low energy, highly focused, pulses in the presence of liquid. Microbubbles that result from laser energy deposition gently expand and extrude machining debris from the channels. These bubbles are in a highly damped, low Reynolds number regime, implying that surface spalling due to bubble collapse is unimportant. We demonstrate rapid prototyping of three-dimensional "jumpers", mixers, and other key components of complex 3D microscale analysis systems in glass substrates. 相似文献
119.
120.
Bukowiecki N Hill M Gehrig R Zwicky CN Lienemann P Hegedüs F Falkenberg G Weingartner E Baltensperger U 《Environmental science & technology》2005,39(15):5754-5762
Trace metals are ubiquitous in urban ambient air, with mass concentrations in the range of a few microg/m3 down to less than 100 pg/m3. To measure such low concentrations represents a challenge for chemical and physical analysis. In this study, ambient aerosol was collected in Zürich (Switzerland) in 1-h intervals and three size fractions (aerodynamic diameters 0.1-1 microm, 1-2.5 microm, and 2.5-10 microm), using a three-stage rotating drum impactor (RDI). The samples were analyzed by energy-dispersive Synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) to obtain size-segregated hourly elemental aerosol mass concentrations for Cr, Mn, Fe, Cu, Zn, Br, and Pb, along with S, Cl, and Ca under the selected experimental conditions. The high sensitivity of SR-XRF allowed for detection limits of <50 pg/m3 for most of the above elements, with a net analysis time of only 15 s per sample. The data obtained with this technique illustrate that there is a considerable gain of relevant information when time resolution for measurements is increased from 1 day to 1 h. The individual size fractions of a specific element may show significantly different short-term patterns. 相似文献