全文获取类型
收费全文 | 23704篇 |
免费 | 1634篇 |
国内免费 | 23篇 |
学科分类
工业技术 | 25361篇 |
出版年
2023年 | 303篇 |
2022年 | 232篇 |
2021年 | 582篇 |
2020年 | 482篇 |
2019年 | 442篇 |
2018年 | 806篇 |
2017年 | 832篇 |
2016年 | 958篇 |
2015年 | 811篇 |
2014年 | 999篇 |
2013年 | 1860篇 |
2012年 | 1251篇 |
2011年 | 1468篇 |
2010年 | 1281篇 |
2009年 | 1125篇 |
2008年 | 1237篇 |
2007年 | 1220篇 |
2006年 | 879篇 |
2005年 | 698篇 |
2004年 | 569篇 |
2003年 | 545篇 |
2002年 | 568篇 |
2001年 | 440篇 |
2000年 | 373篇 |
1999年 | 312篇 |
1998年 | 340篇 |
1997年 | 296篇 |
1996年 | 287篇 |
1995年 | 219篇 |
1994年 | 179篇 |
1993年 | 162篇 |
1992年 | 148篇 |
1991年 | 120篇 |
1990年 | 104篇 |
1989年 | 91篇 |
1988年 | 88篇 |
1987年 | 82篇 |
1985年 | 163篇 |
1984年 | 175篇 |
1983年 | 110篇 |
1982年 | 117篇 |
1981年 | 139篇 |
1980年 | 108篇 |
1979年 | 95篇 |
1978年 | 96篇 |
1977年 | 81篇 |
1976年 | 104篇 |
1975年 | 92篇 |
1974年 | 68篇 |
1973年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Jennie O'Loughlin Silvia Napolitano Fahad Alkhathami Cillian O'Beirne Daniel Marhöfer Megan O'Shaughnessy Prof. Orla Howe Prof. Matthias Tacke Dr. Marina Rubini 《Chembiochem : a European journal of chemical biology》2021,22(6):1093-1098
Antibiotic resistance is a growing problem for public health and associated with increasing economic costs and mortality rates. Silver and silver-related compounds have been used for centuries due to their antimicrobial properties. In this work, we show that 1,3-dibenzyl-4,5-diphenyl-imidazol-2-ylidene silver(I) acetate/NHC*-Ag-OAc (SBC3) is a reversible, high affinity inhibitor of E. coli thioredoxin reductase (TrxR; Ki=10.8±1.2 nM). Minimal inhibition concentration (MIC) tests with different E. coli and P. aeruginosa strains demonstrated that SBC3 can efficiently inhibit bacterial cell growth, especially in combination with established antibiotics like gentamicin. Our results show that SBC3 is a promising antibiotic drug candidate targeting bacterial TrxR. 相似文献
12.
Fischer-Tropsch synthesis of the CO2 in biogas aims at producing light hydrocarbons and increasing its calorific value for feeding into the grid. Fe catalysts with Mn and K as promoters are supposed to yield high amounts of light hydrocarbons. Using a Fe-Mn-K/MgO catalyst, a parameter screening and long-term experiments were carried out. The catalyst shows, within the examined range, the highest selectivity to C2–C4 hydrocarbons at 450 °C, 8 bar(a), and a gas hourly space velocity of 350 h−1. Calcination of the catalyst resulted in a significant drop of activity and an almost complete loss of selectivity to hydrocarbons. Admixture of steam to the reactant gas lowers the tendency to carbon deposition but also promotes the water-gas shift reaction and results in lower yields of hydrocarbons. 相似文献
13.
A hybrid sorbent material for removal of hydrogen sulfide from air was developed. The material is based on activated carbon and iron compounds obtained from waste iron(II) sulfate(VI) heptahydrate. The iron salt is deposited on the carbonaceous support and subjected to oxidation (Fe2+ to Fe3+) using atmospheric oxygen under alkaline conditions. An effect of H2O2 addition to the process on the composition of the resultant material was also examined. X-ray diffraction (XRD) analyses confirmed easy conversion of waste FeSO4·7H2O to iron oxides Fe3O4 and FeOOH. The activated carbon supporting iron oxides revealed a higher efficiency in H2S elimination from air compared to the commercial activated carbon, without any modification. 相似文献
14.
Durmuş Burhanettin Temurtaş Hasan Özyön Serdar 《Neural computing & applications》2020,32(22):17097-17113
Neural Computing and Applications - This study presents the design of a tenth-order multiple feedback Chebyshev low-pass filter (MF-C-LPF). Component selection and gain calculation of filters are... 相似文献
15.
16.
Gökelma Mertol Einarsrud Kristian Etienne Tranell Gabriella Friedrich Bernd 《Metallurgical and Materials Transactions B》2020,51(2):850-860
Metallurgical and Materials Transactions B - The quality requirements of aluminum products are steadily increasing, and the presence of non-metallic inclusions have a large impact on the quality of... 相似文献
17.
18.
19.
20.