全文获取类型
收费全文 | 2588篇 |
免费 | 111篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 33篇 |
综合类 | 3篇 |
化学工业 | 710篇 |
金属工艺 | 119篇 |
机械仪表 | 119篇 |
建筑科学 | 52篇 |
矿业工程 | 39篇 |
能源动力 | 91篇 |
轻工业 | 53篇 |
水利工程 | 23篇 |
石油天然气 | 125篇 |
武器工业 | 1篇 |
无线电 | 178篇 |
一般工业技术 | 700篇 |
冶金工业 | 163篇 |
原子能技术 | 76篇 |
自动化技术 | 225篇 |
出版年
2023年 | 14篇 |
2022年 | 33篇 |
2021年 | 162篇 |
2020年 | 66篇 |
2019年 | 66篇 |
2018年 | 92篇 |
2017年 | 103篇 |
2016年 | 84篇 |
2015年 | 77篇 |
2014年 | 101篇 |
2013年 | 177篇 |
2012年 | 178篇 |
2011年 | 157篇 |
2010年 | 125篇 |
2009年 | 112篇 |
2008年 | 115篇 |
2007年 | 110篇 |
2006年 | 65篇 |
2005年 | 66篇 |
2004年 | 62篇 |
2003年 | 53篇 |
2002年 | 57篇 |
2001年 | 36篇 |
2000年 | 46篇 |
1999年 | 29篇 |
1998年 | 33篇 |
1997年 | 29篇 |
1996年 | 30篇 |
1995年 | 36篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1992年 | 20篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 11篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 16篇 |
1978年 | 18篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1975年 | 20篇 |
1974年 | 17篇 |
1972年 | 19篇 |
1971年 | 16篇 |
1968年 | 13篇 |
排序方式: 共有2710条查询结果,搜索用时 46 毫秒
1.
Olga Yu Kurapova Sergey M. Shugurov Evgenia A. Vasil'eva Daniil A. Savelev Vladimir G. Konakov Sergey I. Lopatin 《Ceramics International》2021,47(8):11072-11079
Ceria-based solid solutions are important materials for high- and medium-temperature electrochemical applications. However, the stabilities of both binary and ternary ceria-based solid solutions are insufficient at elevated temperatures, which limits their application as solid electrolytes or SOFC cathodes. Data on the high-temperature stability of ceria-based ceramics are unavailable in the literature. In the present study, we report a thermodynamic stability investigation of Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions. The thermal prehistories of binary and ternary systems were investigated using STA, XRD, and ESCA techniques. The vaporization processes were investigated in the temperature range of 1577–2227°С via the Knudsen effusion mass spectrometry technique. Using data on the component activity in solid-phase thermodynamic properties of Y2O3-CeO2 solid solutions, which is represented as the Gibbs energy, the excess Gibbs energy was calculated as a function of the ceria mol. %. It was shown that the reduction of Ce4+ to Ce3+ in Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions corresponds to less-negative Gibbs energy compared to ZrO2-CeO2 solid solutions. 相似文献
2.
Khutoryan Eduard Kuleshov Alexei Ponomarenko Sergey Lukin Konstantin Tatematsu Yoshinori Tani Masahiko 《Journal of Infrared, Millimeter and Terahertz Waves》2021,42(6):671-683
Journal of Infrared, Millimeter, and Terahertz Waves - Various regimes of hybrid, bulk-surface, modes being excited in the clinotron oscillator with a sheet electron beam and nonuniform grating... 相似文献
3.
Sergey Bombin Mitchell LeFebvre Jennifer Sherwood Yaolin Xu Yuping Bao Katrina M. Ramonell 《International journal of molecular sciences》2015,16(10):24174-24193
Increasing use of iron oxide nanoparticles in medicine and environmental remediation has led to concerns regarding exposure of these nanoparticles to the public. However, limited studies are available to evaluate their effects on the environment, in particular on plants and food crops. Here, we investigated the effects of positive (PC) and negative (NC) charged iron oxide (Fe2O3) nanoparticles (IONPs) on the physiology and reproductive capacity of Arabidopsis thaliana at concentrations of 3 and 25 mg/L. The 3 mg/L treated plants did not show evident effects on seeding and root length. However, the 25 mg/L treatment resulted in reduced seedling (positive-20% and negative-3.6%) and root (positive-48% and negative-negligible) length. Interestingly, treatment with polyethylenimine (PEI; IONP-PC coating) also resulted in reduced root length (39%) but no change was observed with polyacrylic acid (PAA; IONP-NC coating) treatment alone. However, treatment with IONPs at 3 mg/L did lead to an almost 5% increase in aborted pollen, a 2%–6% reduction in pollen viability and up to an 11% reduction in seed yield depending on the number of treatments. Interestingly, the treated plants did not show any observable phenotypic changes in overall size or general plant structure, indicating that environmental nanoparticle contamination could go dangerously unnoticed. 相似文献
4.
Alena Yarysheva Dmitry Strel'tsov Sergey Malakhov Olga Arzhakova Larisa Yarysheva Alexandr Volynskii 《Polymer International》2020,69(7):627-634
This work addresses the phenomenon of the development of a patterned surface relief on polymer films via different modes of environmental crazing. Commercial films of semicrystalline poly(tetrafluoroethylene) (PTFE) and amorphous glassy poly(ethylene terephthalate) (PET) were subjected to tensile drawing in the presence of physically active liquid environments (carbon tetrachloride or aliphatic alcohols). The structure parameters and wettability of the modified films were studied by AFM, SEM, profilometer measurements and contact angle measurements. Environmental intercrystallite crazing of PTFE is accompanied by the development of an unstable structure with a high free surface, which experiences marked strain recovery upon unloading. As a result of the relief formation, PTFE hydrophobicity is enhanced (the water contact angle increases by 25°). Classical environmental crazing of PET films is accompanied by the formation of an anisotropic surface relief which is an assembly of crazes oriented perpendicular to the direction of tensile drawing, thus leading to the phenomenon of anisotropic wetting. The proposed approach for structural surface modification makes it possible to use the advantages of surface instability and spontaneous self‐organization of the polymer towards the development of a unique surface microrelief. © 2020 Society of Chemical Industry 相似文献
5.
Felix Rivkin Irina Kuznetsova Nadezhda Ivanova Sergey Suhodolsky 《Soil Mechanics and Foundation Engineering》2002,39(1):42-43
Soil Mechanics and Foundation Engineering - 相似文献
6.
7.
Methods are proposed for obtaining the elastic and absorbed components of deformation and mechanical work expended in the region of a nondestructive mechanical effect from the stress-strain diagrams or by calculated prediction. The closeness of the values of the absorbed and correspondingly the elastic components obtained with the measured or predicted stress-strain diagram totally confirm the satisfactory reliability of modeling the physicomechanical properties of a fibre in the form of an integral equation in which the nonlinear-hereditary kernel analytically reflects the activating character of the mechanical effect combined with the concept of the deformation-time analogy in normalized form [5]. 相似文献
8.
N. A. Makarov 《Glass and Ceramics》2007,64(3-4):120-123
A dispersion-hardened material with average flexural strength 580 ± 40 MPa, which is a promising building material, has been
fabricated by introducing a CaO-ZnO-Al2O3-SiO2 eutectic additive and tetragonal zirconium dioxide into aluminum oxide synthesized by calcining the hydroxide. The sintering
temperature of this ceramic is 1550°C. The properties of the eutectic of this system are analyzed, and the optimal liquid-phase
composition which gives intense sintering of the aluminum oxide is determined.
__________
Translated from Steklo i Keramika, No. 4, pp. 12–15, April, 2007. 相似文献
9.
R. Bunk U. Leske R. Krompass Z. Pretch K. Rudolf R. Herbig K. Pitch V. A. Tsykanov O. V. Skiba V. A. Makarov L. P. Bol'shakov P. T. Porodnov A. A. Maershin S. S. Keruchen'ko 《Atomic Energy》1989,67(5):802-806
Translated from Atomnaya Énergiya, Vol. 67, No. 5, pp. 320–323, November, 1989. 相似文献
10.
A theoretical study is reported of the magnetic-field-controlled optical transmission through a stack of identical bilayers in which one layer is bigyrotropic and the other is nonmagnetic and isotropic. An analytical expression for the complex transmittance is derived. The transmittance–wavelength characteristic is examined for different magnetizations and for fixed materials parameters and total number of bilayers. The magnetization dependence of the position, height, and width of the center peak is investigated. The effect is calculated of magnetization on the ellipticity of transmitted light and the angle of optical rotation. 相似文献