全文获取类型
收费全文 | 232篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 55篇 |
金属工艺 | 4篇 |
机械仪表 | 7篇 |
能源动力 | 4篇 |
轻工业 | 31篇 |
石油天然气 | 1篇 |
无线电 | 38篇 |
一般工业技术 | 36篇 |
冶金工业 | 47篇 |
原子能技术 | 1篇 |
自动化技术 | 17篇 |
出版年
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 11篇 |
2012年 | 15篇 |
2011年 | 12篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 6篇 |
2007年 | 11篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 19篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1991年 | 11篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 1篇 |
排序方式: 共有243条查询结果,搜索用时 609 毫秒
1.
Gautier C. Yang Shiren Hofstadter M.D. 《Geoscience and Remote Sensing, IEEE Transactions on》2003,41(2):330-342
A component of the Atmospheric Infrared Sounder (AIRS) instrument system is the AIRS/Visible Near InfraRed (Vis/NIR) instrument. With a nadir ground resolution of 2.28 km and four channels, the Vis/NIR instrument provides diagnostic support to the infrared retrievals from the AIRS instrument and several research products, including surface solar flux studies. The AIRS Vis/NIR is composed of three narrowband (channel 1: 0.40-0.44 /spl mu/m; channel 2: 0.58-0.68 /spl mu/m, and channel 3: 0.71-0.92 /spl mu/m) and one broadband (channel 4: 0.49-0.94 /spl mu/m) channel, each a linear detector array of nine pixels. It is calibrated onboard with three tungsten lamps. Vicarious calibrations using ground targets of known reflectance and a cross-calibration with the Moderate Resolution Imaging Spectroradiometer (MODIS) augment the onboard calibration. One of AIRS Vis/NIR's principal supporting functions is the detection of low clouds to flag these conditions for atmospheric temperature retrievals. Once clouds are detected, a cloud height index is obtained based on the ratio (channel 2 - channel 3)/channel 1 that is sensitive to the partitioning of water vapor absorption above and below clouds. The determination of the surface solar radiation flux is principally based on channel 4 broadband measurements and the well-established relationship between top-of-the atmosphere (broadband) radiance and the surface irradiance. 相似文献
2.
L Lecerf V Rouiller-Fabre C Levacher C Gautier JM Saez R Habert 《Canadian Metallurgical Quarterly》1993,133(5):2313-2318
The in vitro effect of FSH on testosterone secretion by the fetal rat testis was studied. Testes were cultured in the presence or absence of either commercial human (h) FSH (Metrodine; 200 mIU/ml) or recombinant hFSH (200 mIU/ml) for 3 days and with 100 ng/ml ovine LH during the last 4 h of culture. To avoid a stimulatory effect by the 0.4% LH that contaminates Metrodine, the cultures were performed in the presence of a monoclonal anti-hLH beta antibody and with a concentration of Metrodine that had no short term stimulatory effect on testosterone production by the fetal testes in vitro. Metrodine treatment had a positive long term effect on both basal and LH-stimulated testosterone secretion by fetal testes explanted on days 18.5, 20.5, and 22.5 postconception, which was abolished by the addition of a monoclonal anti-hFSH beta antibody. LH-free recombinant FSH also augmented basal and LH-stimulated testosterone secretion of testes explanted on days 13.5, 14.5, and 18.5 postconception. The positive effect of recombinant hFSH appeared during the second day of treatment with day 14.5 and 18.5 testes and on the third day of treatment with day 13.5 testes. As it is widely accepted that FSH receptors are exclusively localized on Sertoli cells, these results suggest that on or before day 15.5 of fetal life, 1) Sertoli cells are able to respond to FSH, 2) Sertoli cells can produce factors that are able to act on Leydig cell function, and 3) Leydig cells are sensitive to FSH-induced Sertoli cell factors. In conclusion, this study points out a potential paracrine control of fetal Leydig cell function and/or differentiation by fetal Sertoli cells as soon as fetal Leydig cells differentiate. 相似文献
3.
Raynaud C. Gautier J. Guegan G. Lerme M. Playez E. Dambrine G. 《Electron Device Letters, IEEE》1991,12(12):667-669
Polycide-gate silicon n-channel MOSFETs were fabricated on the basis of a standard 0.5-μm MOS technology and measured over the 1.5-26.5-GHz frequency range, in order to investigate the effects of channel-length reduction on device behavior at high frequency. Excellent microwave performances were obtained with a maximum operating frequency (f max) and a unity-current-gain frequency f t near 20 GHz for 0.5-μm-gate-length NMOS devices. An equivalent circuit for a MOSFET with its parasitic elements was extracted from measured S-parameter data. The influence of gate resistance, gate-to-drain overlap capacitance, substrate conductivity, and the transit-time effect between the source and drain on microwave characteristics was analyzed 相似文献
4.
M. Charpentier Ph.D. Student D. Daloz E. Gautier G. Lesoult A. Hazotte M. Grange 《Metallurgical and Materials Transactions A》2003,34(10):2139-2148
One major hindrance to effective implementation of cast gamma TiAl-based intermetallic alloys in aircraft engines lies in
the variability of their mechanical properties resulting from chemical and microstructural heterogeneities. In the present
work, the buildup of microsegregation in a cast Ti-48Al-2Cr-2Nb alloy is investigated through experiments of quenching during
directional solidification (QDS). The solidification process, as well as the partitioning of alloying elements, between the
solid and liquid phases, is investigated. Considering experimental conditions, the α-hcp phase is found to be the primary solidifying phase. A low dendrite tip temperature of 1475 °C was estimated from thermal
recordings. These observations could be explained considering the value of the thermal gradient (around 4 °C/mm). Quantitative
values of partition coefficients are proposed for Al, Cr, and Nb. In addition to Al, Cr is found to segregate in interdendritic
regions, whereas Nb tends to be retained in the Ti-rich inner dendrites. Considering experimental cumulative solute distributions,
the buildup of microsegregation can be satisfactorily represented on the basis of Gulliver-Scheil assumptions. Due to high-temperature
quenching, the QDS experiments are also found to be appropriate to the study of high-temperature phase transformations and
microstructural development of TiAl-based alloys. The results of QDS experiments are discussed with regard to the range of
microstructural and chemical heterogeneities determined within Ti-48Al-2Cr-2Nb investment castings. Finally, regarding solid-state
phase transformations subsequent to solidification, the study attempts to explain the formation of B2 phase particles stabilized
by the ternary additions.
This article is based on a presentation made in the symposium entitled “Fundamentals of Structural Intermetallics,” presented
at the 2002 TMS Annual Meeting, February 17–21, 2002, in Seattle, Washington, under the auspices of the ASM and TMS Joint
Committee on Mechanical Behavior of Materials. 相似文献
5.
A new type of velocimeter, capable of local velocity measurements in conducting fluids, is introduced. The principle of the "magnetic-distortion probe" is based on the measurement of the induced magnetic field by the flow of a conducting fluid in the vicinity of a localized magnetic field. The new velocimeter has no moving parts, and can be enclosed in a sealed cap, easing the implementation in harsh environments, such as liquid metals. The proposed method allows one to probe both the continuous part and fluctuations of the velocity, the temporal and spatial resolution being linked to the actual geometric configuration of the probe. A prototype probe has been tested in a gallinstan pipe flow and in a fully turbulent flow of liquid gallium generated by the counter rotation of two coaxial impellers in a cylinder. The signals have been compared to a reference potential probe and show very good agreement both for time-averaged velocities and turbulent fluctuations. The prototype is shown to detect motion from a few cm s(-1) to a few m s(-1). Moreover, the use of the magnetic-distortion probe with large-scale applied magnetic field is discussed. 相似文献
6.
M. Gautier 《野外机器人技术杂志》1991,8(4):485-506
This article presents a new approach to the problem of determining the minimum set of inertial parameters of robots. The calculation is based on numerical QR and SVD factorizations and on the scaling procedure of matrices. It proceeds in three steps:
- eliminate standard inertial parameters which have no effect on the dynamic model,
- determine the number of base parameters,
- determine a set of base parameters by regrouping some standard parameters to some others in linear relations.
7.
Résumé La réduction cathodique de l'oxygène sur des électrodes de manganites de cuivre et liant de Téflon est étudiée par la technique de l'électrode disque-anneau en milieu alcalin. L'interprétation des résultats suggère que la réduction de O2 en OH– procède à la fois par la voie directe et, simultanément, par une voie indirecte, parallèle, qui est constituée de deux étapes en série, avec formation de l'intermédaire HO
2
–
. La réduction directe en OH– (constante de vitessek
1) et la première étape de la réduction indirecte, formant HO
2
–
(constante de vitessek
2) ne dépendent pas de la même manière du potentiel. En outre les ions HO
2
–
peroxyde se décomposent probablement catalytiquement chimiquement sur les manganites de cuivre.
Oxygen reduction on copper manganite Teflon-bonded electrodes in alkaline solution was studied using a rotating ring-disc technique. The interpretation of these data suggests that the cathodic oxygen reduction proceeds through multistep reactions involving a peroxide intermediate. The direct reduction to OH– (k 1) and the first reduction step to HO 2 – (k 2) were found to have different dependences on the potential. Furthermore a catalytic chemical reaction of decomposition of the peroxide intermediate possibly occurs on the manganese copper oxides.相似文献
8.
Jung D Hörlein R Kiefer D Letzring S Gautier DC Schramm U Hübsch C Öhm R Albright BJ Fernandez JC Habs D Hegelich BM 《The Review of scientific instruments》2011,82(1):013306
Here, we report on the development of a novel high resolution and high dispersion Thomson parabola for simultaneously resolving protons and low-Z ions of more than 100 MeV/nucleon necessary to explore novel laser ion acceleration schemes. High electric and magnetic fields enable energy resolutions of ΔE∕E < 5% at 100 MeV/nucleon and impede premature merging of different ion species at low energies on the detector plane. First results from laser driven ion acceleration experiments performed at the Trident Laser Facility demonstrate high resolution and superior species and charge state separation of this novel Thomson parabola for ion energies of more than 30 MeV/nucleon. 相似文献
9.
10.
Laboratory tests were conducted to analyze the ultrasonic velocity response to the pressure change in dry carbonate rocks from the Weyburn oilfield,Canada.Twent... 相似文献