全文获取类型
收费全文 | 524篇 |
免费 | 9篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 47篇 |
金属工艺 | 35篇 |
机械仪表 | 19篇 |
建筑科学 | 1篇 |
能源动力 | 9篇 |
水利工程 | 14篇 |
石油天然气 | 131篇 |
无线电 | 37篇 |
一般工业技术 | 137篇 |
冶金工业 | 44篇 |
原子能技术 | 6篇 |
自动化技术 | 50篇 |
出版年
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 13篇 |
2012年 | 14篇 |
2011年 | 31篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 22篇 |
2007年 | 16篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 18篇 |
2003年 | 18篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 15篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 16篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1987年 | 10篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1971年 | 6篇 |
1970年 | 7篇 |
1968年 | 7篇 |
排序方式: 共有533条查询结果,搜索用时 15 毫秒
351.
F. I. Samedova S. Yu. Rashidova B. M. Aliev 《Chemistry and Technology of Fuels and Oils》2001,37(5):342-346
Naftalan crude oil is the only crude in the world with high therapeutic efficacy. Its therapeutic properties are due to the chemical composition and basic biologically active components, fossil hydrocarbons – naphthenes with isoprenoid chains, steranes, hopanes, etc. [1 – 8]. The necessity of scientifically substantiated refining and rational use of this crude oil makes the study of its chemical composition and the products made from it for medicine urgent. 相似文献
352.
353.
354.
355.
B. L. Zhuikov S. N. Kalmykov S. V. Ermolaev R. A. Aliev V. M. Kokhanyuk V. L. Matushko I. G. Tananaev B. F. Myasoedov 《Radiochemistry》2011,53(1):73-80
The possibility of producing 225Ac and 223Ra by irradiation of natural 232Th with medium-energy protons was examined. Thorium foils were irradiated with 90-, 110-, and 135-MeV protons at the accelerator of the Institute for Nuclear Research, Russian Academy of Sciences, in Troitsk (Moscow oblast). The cumulative production cross sections for 225Ac were 6.7 ± 0.9, 9.8 ± 1.9, and 13.9 ± 1.5 mb, and for 227Th (223Ra precursor), 43 ± 5, 37 ± 6, and 35 ± 4 mb, respectively. Based on the experimental data and theoretical calculations, the possible yields of 225Ac and 223Ra in irradiation of thick thorium targets at various accelerators were determined. An efficient procedure was suggested for isolating the products from the irradiated targets: 225Ac, by liquid extraction and extraction chromatography, and 223Ra, by sublimation from a thorium-lanthanum melt followed by thermochromatographic separation in metallic titanium columns and extraction-chromatographic isolation of radium. The procedure allows production of large (units of curies) amounts of radiochemically pure 225Ac and 223Ra, which is promising for wide use of these radionuclides in nuclear medicine. 相似文献
356.
L. N. Khanov A. B. Batdalov A. M. Aliev S. V. Samoilenkov A. R. Kaul’ 《Technical Physics Letters》2012,38(7):665-667
The electric and thermal conductivity, heat capacity, and thermal diffusivity of thin Ni87.8Cr9.3W2.9 alloy ribbons have been measured. It is established that samples with a cubic texture possess better conducting properties than the nontextured ribbons. The electron and phonon components of thermal conductivity have been separated and their temperature dependence has been traced. Anomalies related to the transition of samples to a ferromagnetic state have been found. 相似文献
357.
R. A. Aliev V. A. Bobrov S. N. Kalmykov A. P. Lisitsyn M. S. Mel’gunov A. N. Novigatskii A. V. Travkina V. P. Shevchenko 《Radiochemistry》2006,48(6):620-625
Vertical profiles of 137Cs in bottom sediments collected from various sites of the White Sea are reported. From these profiles, the 137Cs inventory in the bulk of sediment was estimated to be 270–3300 Bq m?2, and the surface contamination of sediment, 7.1–46.5 Bq kg?1. In the most of the sediment cores, 137Cs was detected to a depth of >20 cm. The highest activity of 137Cs was usually observed in the 1–2-cm layer. The mean specific radioactivity of 137Cs in the seawater was 4.1 Bq m?3. 相似文献
358.
Phase relations in the SrGa2S4-LaGaS3 system were studied by physicochemical analysis, and the SrGa2S4-LaGaS3 phase diagram was mapped out. The system was found to contain the quaternary compound SrLaGa3S7, which melts congruently at 1290 K and has a tetragonal structure. The composition ranges of the SrGa2S4-and SrLaGa3S7-based solid solutions were determined. 相似文献
359.
360.