全文获取类型
收费全文 | 1155篇 |
免费 | 62篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 12篇 |
综合类 | 2篇 |
化学工业 | 456篇 |
金属工艺 | 17篇 |
机械仪表 | 18篇 |
建筑科学 | 21篇 |
矿业工程 | 4篇 |
能源动力 | 49篇 |
轻工业 | 24篇 |
水利工程 | 1篇 |
石油天然气 | 38篇 |
武器工业 | 2篇 |
无线电 | 76篇 |
一般工业技术 | 259篇 |
冶金工业 | 76篇 |
原子能技术 | 21篇 |
自动化技术 | 147篇 |
出版年
2023年 | 14篇 |
2022年 | 90篇 |
2021年 | 88篇 |
2020年 | 35篇 |
2019年 | 33篇 |
2018年 | 52篇 |
2017年 | 25篇 |
2016年 | 49篇 |
2015年 | 31篇 |
2014年 | 34篇 |
2013年 | 67篇 |
2012年 | 71篇 |
2011年 | 70篇 |
2010年 | 57篇 |
2009年 | 39篇 |
2008年 | 60篇 |
2007年 | 46篇 |
2006年 | 38篇 |
2005年 | 30篇 |
2004年 | 26篇 |
2003年 | 30篇 |
2002年 | 28篇 |
2001年 | 10篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 12篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1981年 | 4篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 10篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1969年 | 3篇 |
排序方式: 共有1223条查询结果,搜索用时 0 毫秒
1.
A. N. Gudkov V. M. Zhivun A. V. Zvonarev V. V. Kovalenko A. B. Koldobskii Yu. F. Koleganov S. V. Krivasheev V. B. Pavlovich N. S. Piven' E. V. Semenova 《Atomic Energy》1989,66(2):115-118
Translated from Atomnaya Énergiya, Vol. 66, No. 2, pp. 100–103, February, 1989. 相似文献
2.
Mikhail Sorine Isadora van Riemsdijk 《International Journal of Mechanical Sciences》2008,50(9):1411-1422
This article studies tubular hydroforming of high strength low alloy (HSLA) and dual phase (DP600) straight tubes under the action of end feeding loads. Experiments demonstrate that higher end feed loads enhance the formability of the tubes and increase the internal fluid pressure for onset of necking and bursting. Because of the action of the internal pressure and the axial compressive load, the onset of localization (necking) is due to a complex three-dimensional state of stress. Using free expansion experiments, approximate upper and lower bound strain-based forming limit curves are determined for the tube materials. These limit curves, in turn, are used to derive upper and lower bound extended stress-based forming limit curves [Simha et al., Prediction of necking in tubular hydroforming using an extended stress-based FLC. Transactions of the ASME Journal of Engineering Materials and Technology 2007;129(1): 36-47]. In conjunction with finite element computations that use solid elements to model the tube, these stress-based limit curves are used to predict upper and lower bound necking pressures under the action of end feed loading. These predictions of necking pressures, when an appropriate coefficient of tube-die friction is used, are found to bracket the experimentally measured necking pressures. Computations using plane stress shell elements to model the tubes are shown to give erroneous results, since the plane stress approximation is not valid when tubes are hydroformed in a die. 相似文献
3.
Hiroyuki Miki Takanori Takeno Toshiyuki Takagi Alexei Bozhko Mikhail Shupegin Hideya Onodera Takao Komiyama Takashi Aoyama 《Diamond and Related Materials》2006,15(11-12):1898
Superconductivity in a tungsten-containing carbon-oxide film was reported. The film with 500 nm thickness was deposited onto polycrystalline silicon oxides using chemical vapor deposition and the co-sputtering of a tungsten metal target. The bonding state of the carbon atoms and the macroscopic and microscopic crystal structure of the film were investigated by Raman spectroscopy, X-ray diffraction and transmission electron microscopy measurements. From the experimental results, we determined that this film essentially had an amorphous structure. The temperature dependence on resistivity was measured in the temperature range of 2–300 K. Resistive superconducting transition was observed at 3.8 K. The dc magnetizations were measured in the temperature range of 1.8–6.5 K. The diamagnetism resulting from a superconductive state was observed below 3.75 K, which is consistent with a resistive superconducting transition. It is thought that the finite sized clusters of the different superconductive transition temperatures cooperatively produce a macroscopic superconducting phenomenon. 相似文献
4.
An approach to solve numerically transport equations for plasmas with spontaneously arising and arbitrarily located transport barriers, regions with a strongly reduced transfer of energy, is proposed. The transport equations are written in a form conserving heat flux and solved numerically by using piecewisely exact analytical solutions of linear differential equations. Compared to standard methods, this approach allows to reduce significantly the number of operations required to obtain a converged solution with a heat conductivity changing abruptly at a critical temperature gradient and to use large time steps in modeling the formation and dynamics of transport barriers. Computations for the tokamak JET are done. 相似文献
5.
L. B. Pavlovich N. N. Nazarov V. P. Dolgopolov A. V. Kalinina T. A. Bulis D. V. Bal’tser V. P. Konstantinov 《Coke and Chemistry》2008,51(7):277-282
The use of biochemically purified water in place of industrial-grade water for the exhaust-gas scrubbers in the drying department of the coal-enrichment shop and for irrigation of the cyclone washers in the coke shops at OAO ZSMK is considered. It is found that biochemically purified water may be used for 100% of the water needs in coke production. Using biochemically purified water in the dust-trapping equipment, the coaland coke-dust content of the atmospheric emissions may be reduced by 24.5%. Additional purification of wastewater by adsorption on coke and coal dust is possible. 相似文献
6.
7.
Given a planar setS ofn points,maxdominance problems consist of computing, for everyp S, some function of the maxima of the subset ofS that is dominated byp. A number of geometric and graph-theoretic problems can be formulated as maxdominance problems, including the problem of computing a minimum independent dominating set in a permutation graph, the related problem of finding the shortest maximal increasing subsequence, the problem of enumerating restricted empty rectangles, and the related problem of computing the largest empty rectangle. We give an algorithm for optimally solving a class of maxdominance problems. A straightforward application of our algorithm yields improved time bounds for the above-mentioned problems. The techniques used in the algorithm are of independent interest, and include a linear-time tree computation that is likely to arise in other contexts.The research of this author was supported by the Office of Naval Research under Grants N00014-84-K-0502 and N00014-86-K-0689, and the National Science Foundation under Grant DCR-8451393, with matching funds from AT&T.This author's research was supported by the National Science Foundation under Grant DCR-8506361. 相似文献
8.
Anna A. Pendina Mikhail I. Krapivin Olga A. Efimova Andrei V. Tikhonov Irina D. Mekina Evgeniia M. Komarova Alla S. Koltsova Alexander M. Gzgzyan Igor Yu. Kogan Olga G. Chiryaeva Vladislav S. Baranov 《International journal of molecular sciences》2021,22(11)
The human lifespan is strongly influenced by telomere length (TL) which is defined in a zygote—when two highly specialised haploid cells form a new diploid organism. Although TL is a variable parameter, it fluctuates in a limited range. We aimed to establish the determining factors of TL in chromosomes of maternal and paternal origin in human triploid zygotes. Using Q-FISH, we examined TL in the metaphase chromosomes of 28 human triploid zygotes obtained from 22 couples. The chromosomes’ parental origin was identified immunocytochemically through weak DNA methylation and strong hydroxymethylation in the sperm-derived (paternal) chromosomes versus strong DNA methylation and weak hydroxymethylation in the oocyte-derived (maternal) ones. In 24 zygotes, one maternal and two paternal chromosome sets were identified, while the four remaining zygotes contained one paternal and two maternal sets. For each zygote, we compared mean relative TLs between parental chromosomes, identifying a significant difference in favour of the paternal chromosomes, which attests to a certain “imprinting” of these regions. Mean relative TLs in paternal or maternal chromosomes did not correlate with the respective parent’s age. Similarly, no correlation was observed between the mean relative TL and sperm quality parameters: concentration, progressive motility and normal morphology. Based on the comparison of TLs in chromosomes inherited from a single individual’s gametes with those in chromosomes inherited from different individuals’ gametes, we compared intraindividual (intercellular) and interindividual variability, obtaining significance in favour of the latter and thus validating the role of heredity in determining TL in zygotes. A comparison of the interchromatid TL differences across the chromosomes from sets of different parental origin with those from PHA-stimulated lymphocytes showed an absence of a significant difference between the maternal and paternal sets but a significant excess over the lymphocytes. Therefore, interchromatid TL differences are more pronounced in zygotes than in lymphocytes. To summarise, TL in human zygotes is determined both by heredity and parental origin; the input of other factors is possible within the individual’s reaction norm. 相似文献
9.
Mikhail B. NovikovAlexandra Roos Costantino CretonMikhail M. Feldstein 《Polymer》2003,44(12):3561-3578
Mechanical properties of miscible blends of high molecular weight poly(N-vinyl pyrrolidone) (PVP) with a short-chain, liquid poly(ethylene glycol) (PEG) of molecular weight 400 g/mol have been examined as a function of PVP-PEG composition and degree of hydration. The small-strain behavior in the linear elastic region has been evaluated with the dynamic mechanical analysis and compared with the viscoelastic behavior of PVP-PEG blends under large strains in the course of uniaxial drawing to fracture and under cyclic extension. A strong decoupling between the small-strain and the large strain properties of the blends has been observed, indicative of a pronounced deviation from rubber elasticity in the behavior of the blends. This deviation, also seen on tensile tests under fast drawing, is attributed to the peculiar phase behavior of the blends and the molecular mechanism of PVP-PEG interaction. Nevertheless, for the PVP blend with 36% PEG, under comparatively low extension rates, the reversible contribution to the total work of deformation up to ε=300% has been found to be maximum at around 70%, while the blends containing 31 and 41% PEG behave rather as an elastic-plastic solid and a viscoelastic liquid, respectively. 相似文献
10.
Valerii S. Kozlov Elena P. Yausheva Svetlana A. Terpugova Mikhail V. Panchenko Dmitriy G. Chernov Vladimir P. Shmargunov 《International journal of remote sensing》2014,35(15):5722-5741
A comprehensive experiment on the study of dynamics of optical and microphysical characteristics of submicron aerosols in the near-ground air layer was carried out in June–August of 2012 under conditions of extremely strong smoke haze originating from vast forest fires in Siberia. Variations of the spectral angular scattering coefficients and the degree of linear polarization in the visible wavelength range are studied, as well as the mass concentrations of dry fractions of aerosol and black carbon, relative content of black carbon (BC fraction), single scattering albedo, particle size distribution function, complex refractive index of the particulate matter, and parameter of condensation activity of aerosol. Peculiarities of differences between optical and microphysical characteristics of near-ground aerosol in smoke haze and under smokeless conditions are revealed. This study is important for validation of results of remote sensing of the composition of smoke haze and background atmosphere obtained from satellite data and sun photometric measurements at the Aerosol Robotic Network (AERONET). 相似文献