全文获取类型
收费全文 | 22150篇 |
免费 | 390篇 |
国内免费 | 105篇 |
学科分类
工业技术 | 22645篇 |
出版年
2023年 | 100篇 |
2022年 | 382篇 |
2021年 | 586篇 |
2020年 | 461篇 |
2019年 | 622篇 |
2018年 | 1219篇 |
2017年 | 1247篇 |
2016年 | 1461篇 |
2015年 | 835篇 |
2014年 | 1232篇 |
2013年 | 1645篇 |
2012年 | 1406篇 |
2011年 | 1325篇 |
2010年 | 1261篇 |
2009年 | 1431篇 |
2008年 | 1298篇 |
2007年 | 1231篇 |
2006年 | 1002篇 |
2005年 | 611篇 |
2004年 | 383篇 |
2003年 | 189篇 |
2002年 | 176篇 |
2001年 | 168篇 |
2000年 | 488篇 |
1999年 | 374篇 |
1998年 | 359篇 |
1997年 | 357篇 |
1996年 | 77篇 |
1995年 | 33篇 |
1994年 | 38篇 |
1993年 | 31篇 |
1992年 | 36篇 |
1991年 | 26篇 |
1990年 | 32篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 21篇 |
1986年 | 17篇 |
1985年 | 34篇 |
1984年 | 29篇 |
1983年 | 24篇 |
1980年 | 18篇 |
1979年 | 24篇 |
1978年 | 30篇 |
1977年 | 16篇 |
1976年 | 30篇 |
1975年 | 15篇 |
1974年 | 18篇 |
1969年 | 23篇 |
1968年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
A. S. Roik A. V. Samsonnikov V. P. Kazimirov V. E. Sokol’skii 《Russian Metallurgy (Metally)》2006,(3):206-211
The structures of Al-Ni melts with 0, 10, 18, 25, 28, 32, 40, 75, 90, and 100 at % Ni are studied by X-ray diffraction. The structural models of the melts, which were analyzed by the Voronoi-Delaunay transformation method, are reconstructed by a procedure that is inverse to the Monte Carlo method using experimental structure-factor curves. The parameters characterizing atomic ordering at short and longer distances are determined to change nonmonotonically in the range 10–40 at % Ni with an extreme in the vicinity of the melt containing 28 at % Ni. In this concentration range, nickel atoms are predominantly located in the pentagonal rings of polytetrahedral clusters of the icosahedral type; these atoms are ~4.1 Å from each other. Such clusters generate a prepeak in the structure-factor curves of the melts in the range 10–40 at % Ni. 相似文献
92.
We study some specific features of phase formation and gas saturation in the course of chemical and thermal treatment of VT1-0, OT4, and VT14 titanium alloys in carbon-nitrogen-containing (graphite and nitrogen under atmospheric pressure) and nitrogen-containing (molecular nitrogen under atmospheric pressure) media. Saturation was carried out at 750–1100°C, and the time of isothermal holding was 5 or 20 h. We have shown that, irrespective of the composition of the saturating medium, within the range 750–1000°C, the phase composition of coatings is identical and consists of TiN and Ti2N nitrides. The quantitative proportions between them depend on the temperature and time of treatment. Owing to the specific features of the composition of a carbon-nitrogen-containing medium, the depth of the diffusion sublayer increases, and the stoichiometry of cubic nitride decreases, which leads to an increase in the surface microhardness of nitride coatings. Carbonitride coatings are formed only at high saturation temperature (1100°C). Their maximum hardness is 2.5 GPa higher than that of nitrides formed under similar conditions.Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 40, No. 3, pp. 81–87, May–June, 2004. 相似文献
93.
This paper presents a new massively parallel MIMD architecture, halfway between the Connection Machine and hypercubes based on 32-bit processors. It is built from specific 8-bit processors arranged in a 2-D grid and communicating by message transfers. We discuss the communication problems, the instruction set of the basic processing unit, the programmation of the whole array and the use of a high level data-flow language. 相似文献
94.
A. A. Vaipolin Yu. A. Nikolaev V. Yu. Rud’ Yu. V. Rud’ E. I. Terukov 《Semiconductors》2003,37(4):414-416
Photosensitive structures of surface-barrier and homojunction types have been fabricated for the first time on the basis of ZnIn2Se4 single crystals. The spectral dependence of the quantum efficiency of photoconversion has been studied and discussed. It is concluded that the structures are promising for commercial applications. 相似文献
95.
Ya. Z. Guzel’baev A. L. Khavkin I. G. Khisameev 《Chemical and Petroleum Engineering》2006,42(5-6):320-326
Systems for prevention of surging of centrifugal compressors and methods of rotating stall detection and early surge diagnosis
using statistical processing of sensor signals of various parameters, i.e., the method of calculation of the correlation function
of the signal and the method of calculation of signal dispersion, are discussed. The results of routine tests of air and high-speed
air centrifugal compressors and their detachable flow parts are adduced.
__________
Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 6, pp. 30–33, June, 2006. 相似文献
96.
A. N. Tugov G. A. Ryabov V. I. Rodionov V. I. Ugnachev A. N. Smirnov V. V. Romanov M. E. Gendel’sman I. B. Kolin 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2006,40(5):300-306
Problems that have arisen during tune-up of the production line for the thermal processing of solid household waste by the
method of burning in a vortical fluidized bed (principally, a new technology for Russia), and means of their solution are
presented. Investigative studies are cited.
__________
Translated from élektricheskie Stantsii, No. 6, pp. 20–26, August, 2006. 相似文献
97.
The paper reports the experimental investigation data for the effect that nonparallel faces of bars under impact exert on
the parameters of longitudinal and bending strain waves generated in the bars. The changes in stress magnitudes in the bar
under impact with growing angle of the impact faces offset are described.
__________
Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 73–78, November–December, 2006. 相似文献
98.
B. K. Kardashev A. S. Nefagin G. N. Ermolaev M. V. Leont’eva-Smirnova M. M. Potapenko V. M. Chernov 《Technical Physics Letters》2006,32(9):799-801
The temperature dependences of internal friction (ultrasound decrement) and impact toughness of bcc metals (Fe-12Cr-W-V-Ta-B-C ferritic/martensitic steel, V-4Ti-4Cr vanadium-based alloy) have been studied in a temperature range from 100 to 300 K. The acoustic and mechanical characteristics exhibit correlated variation. The use of nondestructive acoustic techniques for the investigation of mechanisms of the brittle-ductile transition in metallic structural materials is experimentally justified. 相似文献
99.
O. B. Gol’tsova V. S. Klekovkin O. B. Nagovitsin S. V. Antonychev 《Glass and Ceramics》2006,63(3-4):127-129
The results of experimental studies of heat losses via the enclosing structures of an operating brick-firing kiln using a
thermal imager are described.
__________
Translated from Steklo i Keramika, No. 4, pp. 24–25, April, 2006. 相似文献
100.
N. I. Bobyr’ A. P. Grabovskii A. V. Timoshenko A. P. Khalimon 《Strength of Materials》2006,38(1):92-98
Within framework of the continual fracture mechanics, we describe the engineering approach to the assessment of scattered
microdamage accumulation kinetics in metallic materials under elastoplastic loading conditions in case of plane stressed state.
Automatized experimental stand and the respective investigation technique are discussed. The stand has been developed based
on modification of the UMé-10T electromechanic test machine. State-of-the-art computer technologies and microprocessing hardware
are incorporated in the stand automation. We present the technique of experimental assessment of damage accumulation kinetics
in metallic structural materials under complex elastoplastic loading conditions with account of two different fracture (cleavage
and shear) processes, which technique is based on measuring the specific electric resistance of the specimen.
__________
Translated from Problemy Prochnosti, No. 1, pp. 128–137, January–February, 2006. 相似文献