全文获取类型
收费全文 | 411396篇 |
免费 | 6460篇 |
国内免费 | 1810篇 |
专业分类
电工技术 | 6993篇 |
综合类 | 315篇 |
化学工业 | 60624篇 |
金属工艺 | 16953篇 |
机械仪表 | 11997篇 |
建筑科学 | 9737篇 |
矿业工程 | 2046篇 |
能源动力 | 9996篇 |
轻工业 | 35569篇 |
水利工程 | 4110篇 |
石油天然气 | 7799篇 |
武器工业 | 35篇 |
无线电 | 47412篇 |
一般工业技术 | 81329篇 |
冶金工业 | 82909篇 |
原子能技术 | 8824篇 |
自动化技术 | 33018篇 |
出版年
2021年 | 3443篇 |
2020年 | 2697篇 |
2019年 | 3136篇 |
2018年 | 5927篇 |
2017年 | 5880篇 |
2016年 | 6273篇 |
2015年 | 4207篇 |
2014年 | 6708篇 |
2013年 | 18373篇 |
2012年 | 11020篇 |
2011年 | 14350篇 |
2010年 | 11689篇 |
2009年 | 13071篇 |
2008年 | 13753篇 |
2007年 | 13617篇 |
2006年 | 11976篇 |
2005年 | 10968篇 |
2004年 | 10292篇 |
2003年 | 9862篇 |
2002年 | 9522篇 |
2001年 | 9421篇 |
2000年 | 8890篇 |
1999年 | 9459篇 |
1998年 | 26025篇 |
1997年 | 18197篇 |
1996年 | 13877篇 |
1995年 | 9950篇 |
1994年 | 8974篇 |
1993年 | 8758篇 |
1992年 | 6094篇 |
1991年 | 6031篇 |
1990年 | 5820篇 |
1989年 | 5647篇 |
1988年 | 5435篇 |
1987年 | 4492篇 |
1986年 | 4535篇 |
1985年 | 5174篇 |
1984年 | 4839篇 |
1983年 | 4359篇 |
1982年 | 4172篇 |
1981年 | 4290篇 |
1980年 | 4045篇 |
1979年 | 3883篇 |
1978年 | 3907篇 |
1977年 | 4562篇 |
1976年 | 6256篇 |
1975年 | 3473篇 |
1974年 | 3297篇 |
1973年 | 3319篇 |
1972年 | 2856篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Evangelopoulos Xenophon Brockmeier Austin J. Mu Tingting Goulermas John Y. 《Machine Learning》2019,108(4):595-626
Machine Learning - We propose a set of highly scalable algorithms for the combinatorial data analysis problem of seriating similarity matrices. Seriation consists of finding a permutation of data... 相似文献
72.
Scientometrics - The purpose of this study is to ascertain the suitability of GS’s url-based method as a valid approximation of universities’ academic output measures, taking into... 相似文献
73.
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
74.
Kazantsev Yu. N. Kraftmakher G. A. Mal’tsev V. P. 《Journal of Communications Technology and Electronics》2019,64(6):550-554
Journal of Communications Technology and Electronics - Approximate formulas for calculating the coefficient of reflection from an artificial magnetic conductor (AMC) based on a capacitive lattice... 相似文献
75.
G. Inglese 《Inverse Problems in Science & Engineering》2019,27(4):439-459
We deal with the mathematical model of the incremental degradation of the internal coating (e.g. a polymeric material) of a metallic pipe in which a fluid flows relatively fast. The fluid drags solid impurities so that longitudinal scratches, inaccessible to any direct inspection procedure, are produced on the coating. Time evolution of this kind of defects can be reconstructed from the knowledge of a sequence of temperature maps of the external surface. The time-varying orthogonal section of this damaged interface is determined as a function of time and polar angle through the identification of a suitable effective heat transfer coefficient by means of Thin Plate Approximation. 相似文献
76.
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
77.
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
78.
Dr. Lina Liang Tong-You Wade Wei Pei-Yu Wu Wouter Herrebout Ming-Daw Tsai Prof. Stéphane P. Vincent 《Chembiochem : a European journal of chemical biology》2020,21(20):2982-2990
d -Glycero-d -manno-heptose-1β,7-bisphosphate (HBP) and d -glycero-d -manno-heptose-1β-phosphate (H1P) are bacterial metabolites that were recently shown to stimulate inflammatory responses in host cells through the activation of the TIFA-dependent NF-κB pathway. To better understand structure-based activity in relation to this process, a family of nonhydrolyzable phosphonate analogues of HBP and H1P was synthesized. The inflammation modulation by which these molecules induce the TIFA-NF-κB signal axis was evaluated in vivo at a low-nanomolar concentration (6 nM) and compared to that of the natural metabolites. Our data showed that three phosphonate analogues had similar stimulatory activity to HBP, whereas two phosphonates antagonized HBP-induced TIFA-NF-κB signaling. These results open new horizons for the design of pro-inflammatory and innate immune modulators that could be used as vaccine adjuvant. 相似文献
79.
E. G. Kulapina N. M. Makarova O. I. Kulapina I. A. Utc V. V. Baraguzina 《Petroleum Chemistry》2015,55(10):892-900
Potentiometric sensors with plasticized poly(vinyl chloride) membranes based on β-lactam–tetraalkylammonium ion associates sensitive to penicillin antibiotics are proposed. The physicochemical characteristics (solubility product constants and dissociation constants) of active membrane components and the electrode, transport, and selective properties of the membranes of liquidand solid-contact sensors have been studied. The quantitative characteristics of membrane transport (penetrability, ion flux, and transport rate) have been evaluated. The main charge carriers in the membranes and at the membrane/solution interface have been determined from the membrane transport characteristics. The potentiometric sensors are shown to be applicable to the determination of penicillin antibiotics in biological fluids (blood serum and oral fluid) from patients with urinary tract infection. 相似文献
80.