全文获取类型
收费全文 | 517726篇 |
免费 | 6035篇 |
国内免费 | 1678篇 |
专业分类
电工技术 | 10001篇 |
综合类 | 582篇 |
化学工业 | 77783篇 |
金属工艺 | 24339篇 |
机械仪表 | 18400篇 |
建筑科学 | 12304篇 |
矿业工程 | 2453篇 |
能源动力 | 11393篇 |
轻工业 | 45926篇 |
水利工程 | 5036篇 |
石油天然气 | 7337篇 |
武器工业 | 35篇 |
无线电 | 58110篇 |
一般工业技术 | 100566篇 |
冶金工业 | 95553篇 |
原子能技术 | 9912篇 |
自动化技术 | 45709篇 |
出版年
2021年 | 3488篇 |
2019年 | 3297篇 |
2018年 | 12568篇 |
2017年 | 12940篇 |
2016年 | 9902篇 |
2015年 | 4365篇 |
2014年 | 6777篇 |
2013年 | 20012篇 |
2012年 | 13131篇 |
2011年 | 22198篇 |
2010年 | 18906篇 |
2009年 | 19193篇 |
2008年 | 19801篇 |
2007年 | 21749篇 |
2006年 | 13135篇 |
2005年 | 14758篇 |
2004年 | 12980篇 |
2003年 | 12497篇 |
2002年 | 11741篇 |
2001年 | 11159篇 |
2000年 | 10568篇 |
1999年 | 11023篇 |
1998年 | 27495篇 |
1997年 | 19273篇 |
1996年 | 14955篇 |
1995年 | 11328篇 |
1994年 | 10065篇 |
1993年 | 9776篇 |
1992年 | 7248篇 |
1991年 | 6962篇 |
1990年 | 6770篇 |
1989年 | 6553篇 |
1988年 | 6369篇 |
1987年 | 5477篇 |
1986年 | 5445篇 |
1985年 | 6399篇 |
1984年 | 5894篇 |
1983年 | 5313篇 |
1982年 | 4977篇 |
1981年 | 5065篇 |
1980年 | 4851篇 |
1979年 | 4611篇 |
1978年 | 4643篇 |
1977年 | 5452篇 |
1976年 | 7587篇 |
1975年 | 4029篇 |
1974年 | 3799篇 |
1973年 | 3916篇 |
1972年 | 3259篇 |
1971年 | 2993篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
Kozhitov L. V. Kiselev B. G. Raykova T. B. Popkova A. V. Kostishin V. G. Muratov D. G. Yakushko E. V. Kosushkin V. G. Bebenin V. G. 《Russian Microelectronics》2019,48(8):599-612
Russian Microelectronics - The recently developed nanomaterials and their production technologies as intellectual property objects (IPOs) are considered. The role of the informational-analytical... 相似文献
112.
113.
Spiridonova E. A. Rotko V. O. Samonin V. V. Podvyaznikov M. L. 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(1):45-51
Protection of Metals and Physical Chemistry of Surfaces - In this work, a universal sorbent has been obtained that works according to the mechanisms of chemisorption and adsorption by impregnating... 相似文献
114.
Lydia Saidi Dr. Djenisa H. A. Rocha Dr. Oualid Talhi Dr. Yamina Bentarzi Prof. Dr. Bellara Nedjar-Kolli Dr. Khaldoun Bachari Dr. Filipe A. Almeida Paz Dr. Luisa A. Helguero Prof. Dr. Artur M. S. Silva 《ChemMedChem》2019,14(10):1041-1048
Breast and prostate cancers are frequently treated with chemotherapy. Several novel chemicals are being reported for this purpose, particularly synthetic and natural benzophenones. This work reports the synthesis of substituted 2-hydroxybenzophenones through 1,4-conjugate addition/intramolecular cycloaddition/dehydration of nitromethane on key intermediate chromones. Structures were extensively studied by means of 2D NMR spectroscopy and single-crystal XRD. Their cytotoxicity was evaluated in vitro in two breast cancer cell lines (MDA-MB-231 and T47-D) and one prostate cancer cell line (PC3). The most potent compound exhibited good cytotoxic effects against the three cancer cell lines (IC50 values ranging from 12.09 to 26.49 μm ) and induced cell-cycle retardation only on prostate cancer cells, which suggested that it might exert cell-type-specific effects. 相似文献
115.
Byakova O. V. Stepanov G. V. Vlasov A. O. Danylyuk V. E. Semenov N. V. Berezovs’kyi O. M. Gnyloskurenko S. V. 《Strength of Materials》2019,51(5):726-734
Strength of Materials - The paper addresses the investigation of high-strain rate compressive behavior of Al foams subjected to impact at the intermediate striking velocity ranged from 40 to... 相似文献
116.
Theoretical Foundations of Chemical Engineering - Using chemical and XRD phase analysis, along with electron microscopy, the hydrolytic processing of metallic bismuth into high-purity citrate has... 相似文献
117.
Russian Engineering Research - Improvement in the wear resistance of plunger-pump rods is considered. Hardening by high-frequency current is proposed. 相似文献
118.
Bram H. Frohock Jessica M. Gilbertie Dr. Jennifer C. Daiker Dr. Lauren V. Schnabel Dr. Joshua G. Pierce 《Chembiochem : a European journal of chemical biology》2020,21(7):933-937
The failure of frontline antibiotics in the clinic is one of the most serious threats to human health and requires a multitude of novel therapeutics and innovative approaches to treatment so as to curtail the growing crisis. In addition to traditional resistance mechanisms resulting in the lack of efficacy of many antibiotics, most chronic and recurring infections are further made tolerant to antibiotic action by the presence of biofilms. Herein, we report an expanded set of 5-benzylidene-4-oxazolidinones that are able to inhibit the formation of Staphylococcus aureus biofilms, disperse preformed biofilms, and, in combination with common antibiotics, are able to significantly reduce the bacterial load in a robust collagen-matrix model of biofilm infection. 相似文献
119.
120.
The separation of iron oxide from banded hematite jasper(BHJ) assaying 47.8% Fe, 25.6% Si O2 and 2.30%Al2O3 using selective magnetic coating was studied. Characterization studies of the low grade ore indicate that besides hematite and goethite,jasper, a microcrystalline form of quartzite, is the major impurity associated with this ore. Beneficiation by conventional magnetic separation technique could yield a magnetic concentrate containing 60.8% Fe with 51% Fe recovery. In order to enhance the recovery of the iron oxide minerals, fine magnetite, colloidal magnetite and oleate colloidal magnetite were used as the coating material. When subjected to magnetic separation, the coated ore produces an iron concentrate containing 60.2% Fe with an enhanced recovery of56%. The AFM studies indicate that the coagulation of hematite particles with the oleate colloidal magnetite facilitates the higher recovery of iron particles from the low grade BHJ iron ore under appropriate conditions. 相似文献