全文获取类型
收费全文 | 168627篇 |
免费 | 1200篇 |
国内免费 | 186篇 |
专业分类
电工技术 | 2556篇 |
综合类 | 121篇 |
化学工业 | 26658篇 |
金属工艺 | 9475篇 |
机械仪表 | 5716篇 |
建筑科学 | 3009篇 |
矿业工程 | 1887篇 |
能源动力 | 2706篇 |
轻工业 | 8822篇 |
水利工程 | 2742篇 |
石油天然气 | 8694篇 |
武器工业 | 12篇 |
无线电 | 14496篇 |
一般工业技术 | 38267篇 |
冶金工业 | 27804篇 |
原子能技术 | 6938篇 |
自动化技术 | 10110篇 |
出版年
2018年 | 2978篇 |
2017年 | 3092篇 |
2016年 | 3348篇 |
2015年 | 1682篇 |
2014年 | 2956篇 |
2013年 | 6343篇 |
2012年 | 4312篇 |
2011年 | 5398篇 |
2010年 | 4422篇 |
2009年 | 4895篇 |
2008年 | 4941篇 |
2007年 | 4870篇 |
2006年 | 4141篇 |
2005年 | 3820篇 |
2004年 | 3635篇 |
2003年 | 3520篇 |
2002年 | 3450篇 |
2001年 | 3463篇 |
2000年 | 3363篇 |
1999年 | 3214篇 |
1998年 | 7021篇 |
1997年 | 5149篇 |
1996年 | 3822篇 |
1995年 | 2917篇 |
1994年 | 2595篇 |
1993年 | 2723篇 |
1992年 | 2255篇 |
1991年 | 2307篇 |
1990年 | 2409篇 |
1989年 | 2315篇 |
1988年 | 2316篇 |
1987年 | 2191篇 |
1986年 | 2247篇 |
1985年 | 2296篇 |
1984年 | 2211篇 |
1983年 | 2138篇 |
1982年 | 1981篇 |
1981年 | 2193篇 |
1980年 | 2062篇 |
1979年 | 2270篇 |
1978年 | 2436篇 |
1977年 | 2436篇 |
1976年 | 3103篇 |
1975年 | 2245篇 |
1974年 | 2309篇 |
1973年 | 2346篇 |
1972年 | 2156篇 |
1971年 | 1912篇 |
1970年 | 1701篇 |
1969年 | 1632篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
I.?I.?SalakhovEmail author A.?Z.?Batyrshin S.?A.?Sergeev G.?D.?Bukatov A.?A.?Barabanov A.?G.?Sakhabutdinov V.?A.?Zakharov Kh.?Kh.?Gilmanov 《Catalysis in Industry》2014,6(3):198-201
A comparative study of propylene polymerization in liquid monomer is performed under laboratory conditions using the IK-8-21 Ti-Mg catalyst designed at the Boreskov Institute of Catalysis and imported industrial catalysts (conditionally labeled TMC-1, -2, and -3). The activity and stereospecificity of the catalysts are estimated along with properties of the resulting polypropylene (granular composition and physicomechanical characteristics). It is shown that the IK-8-21 catalyst is not inferior to imported counterparts in terms of catalytic properties in the synthesis of polypropylene. The polypropylene powder formed on IK-8-21 is homogeneous and has good morphology. The physicomechanical characteristics of polypropylene synthesized on the domestic IK-8-21 catalyst are similar to those for polypropylene prepared with the imported TMK-1 catalyst. 相似文献
82.
Metals and Materials International - In the present work, Ni32-x-Ti-Ta18+x (x?=?0, 2, 3, 4, 5, 6, 7, 8) shape memory alloys, produced by arc-melting method. Then, differential scanning... 相似文献
83.
Solovtsova O. V. Shkolin A. V. Men’shchikov I. E. Knyazeva M. K. Fomkin A. A. Tsivadze A. Yu. Aksyutin O. E. Ishkov A. G. Khozina E. V. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(6):1080-1084
Protection of Metals and Physical Chemistry of Surfaces - In the present work, a method for producing new shaped composite materials by introducing a metal-organic framework structure Cu-BTC110... 相似文献
84.
Goncharova O. A. Luchkin A. Yu. Kuznetsov Yu. I. Andreev N. N. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(7):1299-1303
Protection of Metals and Physical Chemistry of Surfaces - The atmospheric corrosion resistance of metals can be reached by the formation of ultrathin protective films on their surface. Over recent... 相似文献
85.
Petrunin M. A. Maksaeva L. B. Rybkin A. A. Gladkikh N. A. Yurasova T. A. Maleeva M. A. Marshakov A. I. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(7):1335-1340
Protection of Metals and Physical Chemistry of Surfaces - Protective properties of polymer coatings are mainly determined by their adhesion properties. Organosilanes represent the most commonly... 相似文献
86.
Dorofeeva T. I. Gubaidullina T. A. Gritsenko B. P. Sergeev V. P. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(4):695-699
Protection of Metals and Physical Chemistry of Surfaces - In this work, preparation of thermal barrier coatings based on zirconium oxide is shown. The phased treatment of the copper substrate is... 相似文献
87.
Kazarinov I. A. Isaicheva L. A. Makhmmod Adiba A. Trepak N. M. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(4):700-705
Protection of Metals and Physical Chemistry of Surfaces - Kinetics of formation of phosphate coatings (PCs) on St3 carbon steel in zinc nitrate–phosphate solution (0.65 М Zn2+ + 0.3... 相似文献
88.
Rudnev V. S. Lukiyanchuk I. V. Vasilyeva M. S. Zvereva A. A. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(4):719-728
Protection of Metals and Physical Chemistry of Surfaces - The effect of the temperature of annealing in air on the surface architecture and composition of oxide layers has been studied.... 相似文献
89.
Sara Barrasa-Ramos Claire A. Dessalles Mathieu Hautefeuille Abdul I. Barakat 《Journal of the Royal Society Interface》2022,19(197)
Favouring or thwarting the development of a vascular network is essential in fields as diverse as oncology, cardiovascular disease or tissue engineering. As a result, understanding and controlling angiogenesis has become a major scientific challenge. Mechanical factors play a fundamental role in angiogenesis and can potentially be exploited for optimizing the architecture of the resulting vascular network. Largely focusing on in vitro systems but also supported by some in vivo evidence, the aim of this Highlight Review is dual. First, we describe the current knowledge with particular focus on the effects of fluid and solid mechanical stimuli on the early stages of the angiogenic process, most notably the destabilization of existing vessels and the initiation and elongation of new vessels. Second, we explore inherent difficulties in the field and propose future perspectives on the use of in vitro and physics-based modelling to overcome these difficulties. 相似文献
90.
Sneana Hini April Rich Nicole V. Anayannis Stephanie Cabarcas-Petroski Laura Schramm Patricio I. Meneses 《International journal of molecular sciences》2022,23(18)
High-risk human papillomaviruses (HPV) are important agents, responsible for a large percentage of the 745,000 cases of head and neck squamous cell carcinomas (HNSCC), which were identified worldwide in 2020. In addition to being virally induced, tobacco and heavy alcohol consumption are believed to cause DNA damage contributing to the high number of HNSCC cases. Gene expression and DNA methylation differ between HNSCC based on HPV status. We used publicly available gene expression and DNA methylation profiles from the Cancer Genome Atlas and compared HPV positive and HPV negative HNSCC groups. We used differential gene expression analysis, differential methylation analysis, and a combination of these two analyses to identify the differences. Differential expression analysis identified 1854 differentially expressed genes, including PCNA, TNFRSF14, TRAF1, TRAF2, BCL2, and BIRC3. SYCP2 was identified as one of the top deregulated genes in the differential methylation analysis and in the combined differential expression and methylation analyses. Additionally, pathway and ontology analyses identified the extracellular matrix and receptor interaction pathway as the most altered between HPV negative and HPV positive HNSCC groups. Combining gene expression and DNA methylation can help in elucidating the genes involved in HPV positive HNSCC tumorigenesis, such as SYCP2 and TAF7L. 相似文献