全文获取类型
| 收费全文 | 694篇 |
| 免费 | 4篇 |
专业分类
| 电工技术 | 18篇 |
| 化学工业 | 166篇 |
| 金属工艺 | 84篇 |
| 机械仪表 | 30篇 |
| 建筑科学 | 5篇 |
| 矿业工程 | 3篇 |
| 轻工业 | 26篇 |
| 水利工程 | 8篇 |
| 石油天然气 | 60篇 |
| 武器工业 | 4篇 |
| 无线电 | 38篇 |
| 一般工业技术 | 114篇 |
| 冶金工业 | 99篇 |
| 原子能技术 | 31篇 |
| 自动化技术 | 12篇 |
出版年
| 2022年 | 18篇 |
| 2021年 | 28篇 |
| 2020年 | 15篇 |
| 2019年 | 13篇 |
| 2018年 | 15篇 |
| 2017年 | 24篇 |
| 2016年 | 32篇 |
| 2015年 | 8篇 |
| 2014年 | 17篇 |
| 2013年 | 24篇 |
| 2012年 | 21篇 |
| 2011年 | 27篇 |
| 2010年 | 20篇 |
| 2009年 | 18篇 |
| 2008年 | 24篇 |
| 2007年 | 33篇 |
| 2006年 | 19篇 |
| 2005年 | 13篇 |
| 2004年 | 17篇 |
| 2003年 | 13篇 |
| 2002年 | 11篇 |
| 2000年 | 15篇 |
| 1999年 | 8篇 |
| 1998年 | 13篇 |
| 1997年 | 12篇 |
| 1996年 | 13篇 |
| 1995年 | 6篇 |
| 1993年 | 11篇 |
| 1992年 | 6篇 |
| 1991年 | 7篇 |
| 1990年 | 8篇 |
| 1989年 | 7篇 |
| 1987年 | 10篇 |
| 1986年 | 9篇 |
| 1985年 | 7篇 |
| 1983年 | 7篇 |
| 1981年 | 6篇 |
| 1980年 | 6篇 |
| 1979年 | 7篇 |
| 1978年 | 8篇 |
| 1977年 | 8篇 |
| 1976年 | 17篇 |
| 1975年 | 6篇 |
| 1974年 | 6篇 |
| 1972年 | 5篇 |
| 1971年 | 7篇 |
| 1970年 | 10篇 |
| 1969年 | 9篇 |
| 1967年 | 6篇 |
| 1966年 | 6篇 |
排序方式： 共有698条查询结果，搜索用时 15 毫秒
151.
152.
153.
154.
I. G. Brodova I. G. Shirinkina A. N. Petrova O. V. Antonova V. P. Pilyugin 《The Physics of Metals and Metallography》2011,111(6):630-638
The effect of the degree of deformation upon torsion under quasi-hydrostatic pressure on the structural and phase transformations in the V95 alloy has been studied by the methods of electron microscopy and X-ray diffraction. It has been found that, upon severe plastic deformation, a nanocrystalline structure with a hardness of 2.5 GPa is formed. The nanostructure with a minimum average grain size of 55–80 nm is being formed at e = 5.5–6.4. It has been shown that during dynamical strain aging at e ≥ 4.8, a hardening metastable phase MgZn2 precipitates from the supersaturated α solid solution, and the quantity of this phase increases with increasing degree of deformation. 相似文献
155.
Elmira Khusnutdinova Anastasiya Petrova Zulfia Zileeva Ulyana Kuzmina Liana Zainullina Yulia Vakhitova Denis Babkov Oxana Kazakova 《International journal of molecular sciences》2021,22(18)
A series of A-ring modified oleanolic and ursolic acid derivatives including C28 amides (3-oxo-C2-nicotinoylidene/furfurylidene, 3β-hydroxy-C2-nicotinoylidene, 3β-nicotinoyloxy-, 2-cyano-3,4-seco-4(23)-ene, indolo-, lactame and azepane) were synthesized and screened for their cytotoxic activity against the NCI-60 cancer cell line panel. The results of the first assay of thirty-two tested compounds showed that eleven derivatives exhibited cytotoxicity against cancer cells, and six of them were selected for complete dose–response studies. A systematic study of local SARs has been carried out by comparative analysis of potency distributions and similarity relationships among the synthesized compounds using network-like similarity graphs. Among the oleanane type triterpenoids, C2-[4-pyridinylidene]-oleanonic C28-morpholinyl amide exhibited sub-micromolar potencies against 15 different tumor cell lines and revealed particular selectivity for non-small cell lung cancer (HOP-92) with a GI50 value of 0.0347 μM. On the other hand, superior results were observed for C2-[3-pyridinylidene]-ursonic N-methyl-piperazinyl amide 29, which exhibited a broad-spectrum inhibition activity with GI50 < 1 μM against 33 tumor cell lines and <2 μM against all 60 cell lines. This compound has been further evaluated for cell cycle analysis to decipher the mechanism of action. The data indicate that compound 29 could exhibit both cytostatic and cytotoxic activity, depending on the cell line evaluated. The cytostatic activity appears to be determined by induction of the cell cycle arrest at the S (MCF-7, SH-SY5Y cells) or G0/G1 phases (A549 cells), whereas cytotoxicity of the compound against normal cells is nonspecific and arises from apoptosis without significant alterations in cell cycle distribution (HEK293 cells). Our results suggest that the antiproliferative effect of compound 29 is mediated through ROS-triggered apoptosis that involves mitochondrial membrane potential depolarization and caspase activation. 相似文献
156.
The influence of pitch composition and surface properties of petroleum coke on the interaction of pitch and coke in the composite is studied. The adsorption results and EPR data indicate that recombination of paramagnetic centers and interaction of oxygen functional groups occur during the preparation of the composite. As a result of interaction between petroleum coke and pitch, polar compounds are concentrated in the adsorption layer. The baking criterion is used for the characterization of the baking ability of the pitches obtained as a result of different oxidation treatments of commercial coal tar pitch. It is determined that physico-chemical properties of the obtained pitches influence the value of the “baking criterion”. The kind of thermo-oxidation treatment of the parent pitch should be chosen hence achieving the maximum value of the baking criterion. For this purpose, the maximal part of the pitch has to take part in the adsorption layer. 相似文献
157.
介绍了过氯酰胺盐的一些性质,指出过氯酰胺盐是激光起爆阈值低的光敏炸药。用１０％光学透明的聚合物分别５０ｍｇ／ｃｍ＾２的过氯酰胺钾和过氯酰胺钡制１ｃｍ＾２的光敏炸药薄板并进行了实验。Ⅱ的起爆阈值经久０．１Ｊ／ｃｍ＾２,Ⅳ的起爆阈值为５－７ｍＪ／ｃｍ＾２,皆低于压装的叠氮化铅药柱,全都实现了平面起爆。 相似文献
158.
159.
160.