全文获取类型
收费全文 | 412篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 26篇 |
金属工艺 | 9篇 |
机械仪表 | 24篇 |
建筑科学 | 17篇 |
矿业工程 | 1篇 |
轻工业 | 94篇 |
水利工程 | 1篇 |
石油天然气 | 6篇 |
无线电 | 15篇 |
一般工业技术 | 184篇 |
冶金工业 | 1篇 |
自动化技术 | 35篇 |
出版年
2012年 | 27篇 |
2011年 | 45篇 |
2010年 | 2篇 |
2009年 | 7篇 |
2008年 | 39篇 |
2007年 | 35篇 |
2006年 | 34篇 |
2005年 | 28篇 |
2004年 | 15篇 |
2003年 | 21篇 |
2002年 | 18篇 |
2001年 | 18篇 |
2000年 | 16篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 13篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1948年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有413条查询结果,搜索用时 703 毫秒
2.
3.
4.
Some attempts to balance atmospheric emissions of dioxins with deposition have suggested "missing sources." But the evidence disappears in the uncertainties in deposition data. 相似文献
5.
Comparison of Sagnac and Mach-Zehnder ultrafast all-optical interferometric switches based on a semiconductor resonant optical nonlinearity 总被引:1,自引:0,他引:1
We present a theoretical analysis of recently demonstrated ultrafast all-optical interferometric switching devices (based on Sagnac and Mach-Zehnder interferometers) that use a large optical nonlinearity in a resonant regime. These devices achieve ~10-ps switching windows and do not require high-energy optical control pulses. We theoretically analyze and compare one Sagnac and two Mach-Zehnder switching configurations. 相似文献
6.
A method to derive in-water absorption coefficients from total remote-sensing reflectance (ratio of the upwelling radiance to the downwelling irradiance above the surface) analytically is presented. For measurements made in the Gulf of Mexico and Monterey Bay, with concentrations of chlorophyll-a ranging from 0.07 to 50 mg/m(3), comparisons are made for the total absorption coefficients derived with the suggested method and those derived with diffuse attenuation coefficients. For these coastal to open-ocean waters, including regions of upwelling and the Loop Current, the results are as follows: at 440 nm the difference between the two methods is 13.0% (r(2) = 0.96) for total absorption coefficients ranging from 0.02 to 2.0 m(-1); at 488 nm the difference is 14.5% (r(2) = 0.97); and at 550 nm the difference is 13.6% (r(2) = 0.96). The results indicate that the method presented works very well for retrieval of in-water absorption coefficients exclusively from remotely measured signals, and that this method has a wide range of potential applications in oceanic remote sensing. 相似文献
7.
Papazoglou TG Liu WQ Vasiliou A Grassmel R Kalpouzos C Fotakis C 《Applied optics》1996,35(19):3759-3762
Early-arriving photons of 100-fs laser pulses transmitted through highly scattering media have been detected by a streak camera. Because of their partial spatial coherence, they are affected by diffraction from small hidden discontinuities. The experimental data of the patterns are analyzed with Fresnel diffraction theory and then corrected accordingly. Submillimeter hidden objects were scanned and imaged. Diffraction correction resulted in a significantly improved contrast in the hidden object's image. 相似文献
8.
We describe a type of multilayer dielectric coating designed to enhance the intensity of evanescent waves. The coating consists of a stack of alternating high- and low-index quarter-wave layers followed by a final low-index layer whose thickness is chosen to optimize the evanescent-wave intensity. Indirect measurements of the film properties are in good agreement with theory. 相似文献
9.
Stangegaard M Frøslev TG Frank-Hansen R Hansen AJ Morling N 《Journal of laboratory automation》2011,16(2):134-140
We have implemented and validated automated protocols for DNA extraction and PCR setup using a Tecan Freedom EVO liquid handler mounted with the Te-MagS magnetic separation device (Tecan, M?nnedorf, Switzerland). The protocols were validated for accredited forensic genetic work according to ISO 17025 using the Qiagen MagAttract DNA Mini M48 kit (Qiagen GmbH, Hilden, Germany) from fresh whole blood and blood from deceased individuals. The workflow was simplified by returning the DNA extracts to the original tubes minimizing the risk of misplacing samples. The tubes that originally contained the samples were washed with MilliQ water before the return of the DNA extracts. The PCR was setup in 96-well microtiter plates. The methods were validated for the kits: AmpF?STR Identifiler, SGM Plus and Yfiler (Applied Biosystems, Foster City, CA), GenePrint FFFL and PowerPlex Y (Promega, Madison, WI). The automated protocols allowed for extraction and addition of PCR master mix of 96 samples within 3.5h. In conclusion, we demonstrated that (1) DNA extraction with magnetic beads and (2) PCR setup for accredited, forensic genetic short tandem repeat typing can be implemented on a simple automated liquid handler leading to the reduction of manual work, and increased quality and throughput. 相似文献
10.