全文获取类型
收费全文 | 36293篇 |
免费 | 1113篇 |
国内免费 | 173篇 |
专业分类
电工技术 | 766篇 |
综合类 | 155篇 |
化学工业 | 6310篇 |
金属工艺 | 1356篇 |
机械仪表 | 892篇 |
建筑科学 | 1337篇 |
矿业工程 | 204篇 |
能源动力 | 1035篇 |
轻工业 | 3529篇 |
水利工程 | 299篇 |
石油天然气 | 264篇 |
武器工业 | 14篇 |
无线电 | 3433篇 |
一般工业技术 | 6418篇 |
冶金工业 | 7067篇 |
原子能技术 | 509篇 |
自动化技术 | 3991篇 |
出版年
2023年 | 181篇 |
2022年 | 379篇 |
2021年 | 605篇 |
2020年 | 409篇 |
2019年 | 478篇 |
2018年 | 608篇 |
2017年 | 644篇 |
2016年 | 759篇 |
2015年 | 605篇 |
2014年 | 864篇 |
2013年 | 1689篇 |
2012年 | 1261篇 |
2011年 | 1732篇 |
2010年 | 1286篇 |
2009年 | 1290篇 |
2008年 | 1384篇 |
2007年 | 1353篇 |
2006年 | 1134篇 |
2005年 | 1110篇 |
2004年 | 963篇 |
2003年 | 949篇 |
2002年 | 991篇 |
2001年 | 871篇 |
2000年 | 774篇 |
1999年 | 805篇 |
1998年 | 2438篇 |
1997年 | 1609篇 |
1996年 | 1180篇 |
1995年 | 820篇 |
1994年 | 745篇 |
1993年 | 726篇 |
1992年 | 435篇 |
1991年 | 394篇 |
1990年 | 409篇 |
1989年 | 394篇 |
1988年 | 345篇 |
1987年 | 310篇 |
1986年 | 285篇 |
1985年 | 318篇 |
1984年 | 262篇 |
1983年 | 232篇 |
1982年 | 224篇 |
1981年 | 246篇 |
1980年 | 236篇 |
1979年 | 179篇 |
1978年 | 171篇 |
1977年 | 308篇 |
1976年 | 436篇 |
1975年 | 155篇 |
1973年 | 138篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Can Ercan S. Esra Safran Artuğ Türkmenoğlu Uğur Karabakal 《Journal of surfactants and detergents》2021,24(1):139-147
Garzan oil field is located at the south east of Turkey. It is a mature oil field and the reservoir is fractured carbonate reservoir. After producing about 1% original oil in place (OOIP) reservoir pressure started to decline. Waterflooding was started in order to support reservoir pressure and also to enhance oil production in 1960. Waterflooding improved the oil recovery but after years of flooding water breakthrough at the production wells was observed. This increased the water/oil ratio at the production wells. In order to enhance oil recovery again different techniques were investigated. Chemical enhanced oil recovery (EOR) methods are gaining attention all over the world for oil recovery. Surfactant injection is an effective way for interfacial tension (IFT) reduction and wettability reversal. In this study, 31 different types of chemicals were studied to specify the effects on oil production. This paper presents solubility of surfactants in brine, IFT and contact angle measurements, imbibition tests, and lastly core flooding experiments. Most of the chemicals were incompatible with Garzan formation water, which has high divalent ion concentration. In this case, the usage of 2-propanol as co-surfactant yielded successful results for stability of the selected chemical solutions. The results of the wettability test indicated that both tested cationic and anionic surfactants altered the wettability of the carbonate rock from oil-wet to intermediate-wet. The maximum oil recovery by imbibition test was reached when core was exposed 1-ethly ionic liquid after imbibition in formation water. Also, after core flooding test, it is concluded that considerable amount of oil can be recovered from Garzan reservoir by waterflooding alone if adverse effects of natural fractures could be eliminated. 相似文献
2.
3.
Michael Lommel Vera Froese Moritz Sieber Marvin Jentzsch Tim Bierewirtz Ümit Hasirci Tim Rese Josef Seefeldt Sebastian Schimek Ulrich Kertzscher Christian Oliver Paschereit 《Indoor air》2021,31(6):1860-1873
The SARS-CoV-2 pandemic has created a great demand for a better understanding of the spread of viruses in indoor environments. A novel measurement system consisting of one portable aerosol-emitting mannequin (emitter) and a number of portable aerosol-absorbing mannequins (recipients) was developed that can measure the spread of aerosols and droplets that potentially contain infectious viruses. The emission of the virus from a human is simulated by using tracer particles solved in water. The recipients inhale the aerosols and droplets and quantify the level of solved tracer particles in their artificial lungs simultaneously over time. The mobile system can be arranged in a large variety of spreading scenarios in indoor environments and allows for quantification of the infection probability due to airborne virus spreading. This study shows the accuracy of the new measurement system and its ability to compare aerosol reduction measures such as regular ventilation or the use of a room air purifier. 相似文献
4.
Jens Mller Anne Busch Christian Berens Helmut Hotzel Andreas Burkovski 《International journal of molecular sciences》2021,22(7)
Corynebacterium silvaticum is a newly identified animal pathogen of forest animals such as roe deer and wild boars. The species is closely related to the emerging human pathogen Corynebacterium ulcerans and the widely distributed animal pathogen Corynebacterium pseudotuberculosis. In this study, Corynebacterium silvaticum strain W25 was characterized with respect to its interaction with human cell lines. Microscopy, measurement of transepithelial electric resistance and cytotoxicity assays revealed detrimental effects of C. silvaticum to different human epithelial cell lines and to an invertebrate animal model, Galleria mellonella larvae, comparable to diphtheria toxin-secreting C. ulcerans. Furthermore, the results obtained may indicate a considerable zoonotic potential of this newly identified species. 相似文献
5.
6.
7.
8.
A contact layer element for large deformations 总被引:1,自引:0,他引:1
9.
Choi Paul Santos Christian Ariane Kim Min-Kun Jung Hyunsook Hong Do-Young Koo Junemo 《Journal of Mechanical Science and Technology》2021,35(11):5007-5022
Journal of Mechanical Science and Technology - This study delivers equations useful for low-height pleated fibrous filter design: two pressure drop equations and one set of optimum design equations... 相似文献
10.