全文获取类型
收费全文 | 5683篇 |
免费 | 163篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 85篇 |
综合类 | 15篇 |
化学工业 | 953篇 |
金属工艺 | 81篇 |
机械仪表 | 99篇 |
建筑科学 | 454篇 |
矿业工程 | 4篇 |
能源动力 | 140篇 |
轻工业 | 686篇 |
水利工程 | 39篇 |
石油天然气 | 4篇 |
无线电 | 372篇 |
一般工业技术 | 741篇 |
冶金工业 | 1379篇 |
原子能技术 | 66篇 |
自动化技术 | 735篇 |
出版年
2023年 | 33篇 |
2022年 | 89篇 |
2021年 | 141篇 |
2020年 | 56篇 |
2019年 | 75篇 |
2018年 | 99篇 |
2017年 | 83篇 |
2016年 | 128篇 |
2015年 | 89篇 |
2014年 | 122篇 |
2013年 | 210篇 |
2012年 | 217篇 |
2011年 | 293篇 |
2010年 | 212篇 |
2009年 | 201篇 |
2008年 | 211篇 |
2007年 | 354篇 |
2006年 | 169篇 |
2005年 | 147篇 |
2004年 | 149篇 |
2003年 | 130篇 |
2002年 | 118篇 |
2001年 | 93篇 |
2000年 | 93篇 |
1999年 | 109篇 |
1998年 | 439篇 |
1997年 | 281篇 |
1996年 | 173篇 |
1995年 | 140篇 |
1994年 | 113篇 |
1993年 | 99篇 |
1992年 | 49篇 |
1991年 | 54篇 |
1990年 | 49篇 |
1989年 | 47篇 |
1988年 | 40篇 |
1987年 | 36篇 |
1986年 | 30篇 |
1985年 | 43篇 |
1984年 | 32篇 |
1983年 | 35篇 |
1982年 | 30篇 |
1981年 | 32篇 |
1980年 | 36篇 |
1979年 | 40篇 |
1978年 | 21篇 |
1977年 | 45篇 |
1976年 | 62篇 |
1974年 | 20篇 |
1973年 | 28篇 |
排序方式: 共有5853条查询结果,搜索用时 31 毫秒
51.
I. Sevostianov N. K. Sookay C. J. von Klemperer V. E. Verijenko 《Composite Structures》2003,62(3-4):417-421
Attempts to model the degradation of polymer composites have been restricted to modelling the effects of selected degradation mechanisms. No comprehensive model has yet been accepted to predict the effect of the natural environment on the strength of polymer composites. From a review of available literature, it appears that the matrix of a polymer composite is most affected by exposure to the natural environment. Further, the damage appears to progress from the surface into the interior of the laminate. An approach has been developed to determine the properties of the damaged layer and combine the properties of the damaged and undamaged layer to obtain bulk material properties of the laminate. 相似文献
52.
P. Kempf M. von Ortenberg R. Bicknell-Tassius A. Waag 《Journal of Infrared, Millimeter and Terahertz Waves》1992,13(2):207-213
Far-infrared magnetotransmission measurements have been performed on MBE-grown HgTe and CdTe epilayers. The results on the HgTe samples can be understood by the standard Pidgeon-Brown model for bulk HgTe. For the CdTe layers, transitions were only observed under illumination by visible light. The spectra are dominated by the 1s→2p transition of the shallow hydrogen-like impurity. These transitions are persistent with a life time of the order of magnitude of one second. 相似文献
53.
Influence of electroosmotic treatment on the hydro-mechanical behaviour of clayey silts: preliminary experimental results 总被引:1,自引:0,他引:1
Laura Gabrieli Cristina Jommi Guido Musso Enrique Romero 《Journal of Applied Electrochemistry》2008,38(7):1043-1051
Preliminary results of an investigation focused on the influence of electrokinetic treatment on the mechanical and hydraulic
behaviour of clayey soils are presented. The experimental programme aims at providing a contribution to the sustainability
of contaminant extraction or containment via electroosmosis. Changes in the hydraulic and mechanical properties of two illitic
clayey soils, subjected to a DC electric field, were investigated. Samples of the two soils were subjected to electrokinetic
filtration, for different periods of time, and under different constant loads. Afterwards, they were tested under one-dimensional
compression to detect changes in stiffness and hydraulic conductivity due to the electrical treatment. After the application
of a DC field for a few hours, a small reversible increment in the average soil stiffness was observed, with respect to the
untreated soil, while the hydraulic conductivity was not affected substantially. Dramatic changes of the mechanical and hydraulic
soil properties, correlated to changes of the soil pH, were observed following non-conditioned electrokinetic treatment with
duration of the order of days. 相似文献
54.
Hodgins D. Bertsch A. Post N. Frischholz M. Volckaerts B. Spensley J. Wasikiewicz J.M. Higgins H. von Stetten F. Kenney L. 《Pervasive Computing, IEEE》2008,7(1):14-21
Healthy Aims is a 23- million, four-year project, funded under the EU's information society technology sixth framework program to develop intelligent medical implants and diagnostic systems (www.healthyaims.org). The project has 25 partners from 10 countries, including commercial, clinical, and research groups. This consortium represents a combination of disciplines to design and fabricate new medical devices and components as well as to test them in laboratories and subsequent clinical trials. The project focuses on medical implants for nerve stimulation and diagnostic equipment based on strain-gauge technology. 相似文献
55.
56.
ML Israel DA Connolly RE von Heyn JM Rock PW Smith 《Canadian Metallurgical Quarterly》1993,24(4):343-355
Fifty-two case-hardened, severely self-abusive and aggressive autistic and retarded students, living in six different community residences, were trained to exit their residences, without the presence or assistance of staff, when a fire alarm sounded at night. On a pretest, prior to an 11-week period of intensive environmental and behavioral interventions, only 25% of the students exited within 2 1/2 minutes and independent of staff assistance. At posttest, 100% exited successfully, in a mean evacuation time of 60 seconds. The study was conducted at the Behavior Research Institute (BRI). 相似文献
57.
G. Eilers M. von Ortenberg R. Galazka 《Journal of Infrared, Millimeter and Terahertz Waves》1994,15(4):695-722
The electron paramagnetic resonance (EPR) of Mn2+ in Cd1?x Mn x Te was examined at low temperatures and high magnetic fields with the Mn concentration ranging fromx=0.01 tox=0.65. A far infrared laser was used as a radiation source. The structure of the resonance is strongly influenced by electromagnetic propagation effects. By variation of the sample thickness it was clearly shown that the satellite structures besides the main EPR peak, formerly explained as originating from transitions in the Mn2+ pair energy level scheme, are solely due to interference effects. 相似文献
58.
59.
Dorn R. Baumgartner A. Goth A. Gutu-Nelle A. Koppenborg J. Rehm W. Schneider R. Schneider S. von Wirth J. Weber D. 《Lightwave Technology, Journal of》1991,9(6):709-714
Mechanically shaped preforms (MSP) have been demonstrated to combine economic non-CVD (chemical vapor deposition) processing and low loss, with a published value of 0.63 dB/km and a size of 30 fkm/preform. Improved processing is proposed which results in a minimum loss of 0.27 dB/km at 1550 nm. Preforms capable of yielding 150 fkm have been produced. Reboiling during preform stretching and fiber pulling is identified as the last remaining problem of the process 相似文献
60.