全文获取类型
收费全文 | 9855篇 |
免费 | 599篇 |
国内免费 | 7篇 |
学科分类
工业技术 | 10461篇 |
出版年
2023年 | 126篇 |
2022年 | 91篇 |
2021年 | 386篇 |
2020年 | 228篇 |
2019年 | 256篇 |
2018年 | 287篇 |
2017年 | 309篇 |
2016年 | 396篇 |
2015年 | 344篇 |
2014年 | 435篇 |
2013年 | 698篇 |
2012年 | 636篇 |
2011年 | 870篇 |
2010年 | 630篇 |
2009年 | 573篇 |
2008年 | 614篇 |
2007年 | 536篇 |
2006年 | 449篇 |
2005年 | 370篇 |
2004年 | 310篇 |
2003年 | 227篇 |
2002年 | 213篇 |
2001年 | 143篇 |
2000年 | 123篇 |
1999年 | 143篇 |
1998年 | 140篇 |
1997年 | 108篇 |
1996年 | 90篇 |
1995年 | 62篇 |
1994年 | 76篇 |
1993年 | 52篇 |
1992年 | 59篇 |
1991年 | 25篇 |
1990年 | 53篇 |
1989年 | 29篇 |
1988年 | 30篇 |
1987年 | 36篇 |
1986年 | 29篇 |
1985年 | 25篇 |
1984年 | 32篇 |
1983年 | 20篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 23篇 |
1978年 | 13篇 |
1977年 | 18篇 |
1976年 | 24篇 |
1975年 | 14篇 |
1974年 | 8篇 |
1969年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 796 毫秒
1.
2.
Brian Lawn David Marshall Rishi Raj Greg Hirth Trevor Page Julie Yeomans 《Journal of the American Ceramic Society》2021,104(1):23-26
Crystalline quartz has long been identified as among the weakest of abundant crustal minerals. This weakness is particularly evident around the α–β phase inversion at 573°C, in which Si–O bonds undergo a displacive structural transformation from trigonal to hexagonal symmetry. Here we present data using indentation testing methodologies that highlight the precipitous extent of the transformational weakening. Although the indentations are localized over relatively small specimen contact areas, the data quantify the essential deformation and fracture properties of quartz in a predominantly (but not exclusively) compressive stress field, at temperatures and pressures pertinent to conditions in the earth's crust. 相似文献
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.
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
9.
10.