全文获取类型
收费全文 | 787篇 |
免费 | 30篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 12篇 |
综合类 | 4篇 |
化学工业 | 225篇 |
金属工艺 | 14篇 |
机械仪表 | 12篇 |
建筑科学 | 51篇 |
矿业工程 | 3篇 |
能源动力 | 10篇 |
轻工业 | 65篇 |
水利工程 | 15篇 |
无线电 | 52篇 |
一般工业技术 | 167篇 |
冶金工业 | 22篇 |
原子能技术 | 3篇 |
自动化技术 | 164篇 |
出版年
2023年 | 6篇 |
2022年 | 14篇 |
2021年 | 29篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 17篇 |
2016年 | 32篇 |
2015年 | 24篇 |
2014年 | 28篇 |
2013年 | 39篇 |
2012年 | 36篇 |
2011年 | 50篇 |
2010年 | 30篇 |
2009年 | 33篇 |
2008年 | 42篇 |
2007年 | 52篇 |
2006年 | 39篇 |
2005年 | 14篇 |
2004年 | 17篇 |
2003年 | 17篇 |
2002年 | 16篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 24篇 |
1998年 | 9篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 12篇 |
1994年 | 13篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1927年 | 2篇 |
1901年 | 2篇 |
排序方式: 共有819条查询结果,搜索用时 0 毫秒
101.
102.
Johann Bizer 《Datenschutz und Datensicherheit - DuD》2007,31(1):2-2
Ohne Zusammenfassung 相似文献
103.
104.
Stefan Hörmansdorfer Manfred Gareis Johann Bauer und Anton Mayr 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1995,201(3):293-297
Tissue culture cells' metabolism and viability are measured by the mitochondrial reduction rate of a yellow tetrazolium salt (MTT) to blue formazan crystalls in the MTT-bioassay. Thus the MTT-bioassay is a standardizable and reproducible bioassay for measuring cytotoxicity or cytostimulation. It is shown that the MTT-bioassay is also very suitable for determining bacterial cytotoxins using Escherichia coli's Shiga-like toxins as example. 177 strains ofE.coli, isolated from carcasses and organs of cattle, are classified biochemically and tested for cytotoxin production by means of the MTT-bioassay. One of these strains is recognized as producer of Shiga-like toxin 2. 4 Enterohemolysin-producing strains ofE.coli are cultivated from a feces sample of a diarrhoeic nubian ibex and identified as Shiga-like toxin 1 producers by help of the MTT-bioassay. 相似文献
105.
In the present paper research work is presented combining material related research, weld fabrication related research and research in the field of numerical analysis of welded joint performance. Elements belonging to this extensive combination are mechanical testing, fracture mechanics testing of small scale and full thickness specimens, component testing including engineering defect assessment and numerical modelling using finite element method. Examples are given for each of the above mentioned elements. 相似文献
106.
107.
108.
U. Johann W. Reiland 《International Journal of Satellite Communications and Networking》1988,6(2):225-230
An experimental optical communications link between two stratospheric balloons is proposed as an intermediate step from limited ground laboratory tests to costly space operations. Such an experiment can overcome many environmental constraints encountered on the ground, and allows all measurements to be made directly in the antenna far field. Early performance demonstrations are possible which allow experimental trade-offs between alternative technologies and the verification of concepts, critical system parameters and subfunctions under near space conditions. 相似文献
109.
Susanne Danhauser Wolfgang E. Berdel Hans D. Schick Michael Fromm Anneliese Reichert Ulrich Fink Raymonde Busch Hansjörg Eibl Johann rastetter 《Lipids》1987,22(11):911-915
Eleven lipids have been tested for cytotoxic (trypan blue dye exclusion) activity in cells from eight freshly explanted human leukemias in vitro. 4-Aminomethyl-1-[2,3-(di-N-decyloxy)N-propyl]-4-phenylpiperidine (CP-46,665), 1-mercapto-hexadecyl-2-methoxymethyl-rac-glycero-3-phosphocholine (BM 41.440), the 2-acetamide analog of platelet-activating factor (PAF) and 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) were found among the most active compounds. 2-Lysophosphatidylcholine (2-LPC) showed the lowest activity. However, in addition there was variation among the results regarding the activity of the 1-octadecyl-rac-glycero-3-phosphocholine (ET-18-OH) and its D- and L-forms, but a significantly higher cytotoxic activity of D-ET-18-OH compared with L-ET-18-OH on the basis of 2-LPC as control after an incubation time of 48 hr. We conclude that with the limited number of structures available, this type of study is not sufficient to yield further information about the mode of the accumulation and toxicity of this type of lipids. 相似文献
110.