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排序方式: 共有314条查询结果,搜索用时 15 毫秒
81.
Artificial Intelligence Review - Process mining enables the reconstruction and evaluation of business processes based on digital traces in IT systems. An increasingly important technique in this...  相似文献   
82.
Topics in Catalysis - Regioselective reactions allow the differentiation between two or more chemically identical reactive centers within the same molecule. They are highly desirable...  相似文献   
83.

Object

Ultra-high field (UHF) neuroimaging is usually conducted with volume transmit (Tx) and phased array receive (Rx) coils, both tightly enclosing the object. The travelling-wave (TW) concept allows a remote excitation offering more flexible experimental setups. To investigate the feasibility of primate MRI in horizontal UHF MRI, we first compared the distribution of the electromagnetic fields in an oil phantom and then verified the concept with an in vivo experiment.

Materials and methods

In the phantom experiments an in-house circularly polarized hybrid birdcage coil and a self-developed patch antenna were used for Tx and an eight-element phased array antenna for Rx. B 1 + fields were calculated and measured for both approaches. For in vivo experiments the Rx part was replaced with an optimized three-element phased array head coil. The SAR was calculated using field simulation.

Results

In the phantom the field distribution was homogenous in a central volume of interest of about 10 cm diameter. The TW concept showed a slightly better homogeneity. Examination of a female crab-eating macaque led to homogeneous high-contrast images with a good delineation of anatomical details.

Conclusion

The TW concept opens up a new approach for MRI of medium-sized animals in horizontal UHF scanners.  相似文献   
84.
Push–pull osmotic systems have been developed to deliver poorly soluble drugs in a modified-release fashion. The aim of this study was to investigate the influence of the tablet core factors on the drug release kinetics and loadability. The release kinetics was efficiently modulated by varying either the proportion of osmotic agent or the drug layer polymer grade as an alternative to change the membrane characteristics. High osmotic agent proportions and viscous-grade polymers were recommended to formulate high drug loads up to 20%?without losing both the release completeness and the zero-order drug release kinetics.  相似文献   
85.
Host country cultural influences on foreign direct investment   总被引:2,自引:0,他引:2  
Abstract and Key Results
–  This paper provides a novel perspective towards understanding the influence of host country culture on the location choices of foreign firms. We argue that host country cultural variables: uncertainty avoidance and trust, influence the location choices of foreign firms such that foreign firms prefer to invest in nations with (1) low levels of uncertainty avoidance and (2) high levels of trust.
–  In addition to direct effects, we hypothesize that uncertainty avoidance moderates the relationship between host country trust and levels of foreign direct investment (FDI) such that the relationship between trust and FDI becomes weaker, as uncertainty avoidance increases.
–  The results in a sample of 43 nations are supportive of the hypothesized main effect of uncertainty avoidance and the moderating effects, and partially supportive of the main effect of trust on FDI, after controlling for economic, human capital, and governance infrastructure variables.
  相似文献   
86.
The rapid growth of the world population, the finiteness of resources on our planet Earth and the ongoing tendency towards urbanisation result in the need to question our actions and economic activities, also for industrial enterprises. A paradigm shift to decouple growth and resource utilisation is needed. By means of ultra-efficiency, factories are targeted, whose positive impact to their surrounding is optimised instead of only minimising negative influences. In the contribution, the concept of ultra-efficient factories and first tools for their implementation are introduced. Therefore, the term ultra-efficient factory is defined based on the state of the art. On this definition, spheres of activity for ultra-efficient factories under consideration of urban surroundings are determined. For the spheres of activity, criteria to assess the according maturity of companies are identified and aggregated into a comprehensive maturity model. The maturity model enables the determination of potentials for advancements of companies. To support the industrial application of the theoretic work, industrial best practices are determined and a visual tool is developed.  相似文献   
87.
Working with wavelengths shorter than the deep ultraviolet involves the development of dedicated optics for free-electron lasers with devoted coating techniques and characterizations. High-performance deep-ultraviolet optics are specially developed to create low-loss, high-reflectivity dielectric mirrors with long lifetimes in harsh synchrotron radiation environments. In February 2001, lasing at 189.7 nm, the shortest wavelength obtained so far with free-electron-laser oscillators, was obtained at the European Free-electron-laser project at ELETTRA Synchrotron Light Laboratory, Trieste, Italy. In July 2001, 330-mW extracted power at 250 nm was measured with optimized transmission mirrors. Research and development of coatings correlated to lasing performance are reported.  相似文献   
88.
In recent years, high-resolution displays have become increasingly important to decision makers and scientists because large screens combined with a high pixel count facilitate content rich, simultaneous display of computer-generated imagery and high-definition video data from multiple sources. Tiled displays are attractive due to their extended screen real estate, scalability, and low cost. LCD panels are usually preferred over projectors because of their superior resolution. One of the drawbacks of LCD-based tiled displays is the fact that users sometimes get distracted by the screens' bezels, which cause discontinuities in rendered images, animations, or videos. Most conventional solutions either ignore the bezels and display all pixels, causing objects to become distorted, or eliminate the pixels that would normally fall under the bezels, causing pixels to be missing in the display of static images. In animations, the missing pixels will eventually reappear when the object moves, providing an experience that is similar to looking through a French window. In this paper, we present a new scalable approach that leads neither to discontinuities nor to significant loss of information. By projecting onto the bezels, we demonstrate that a combination of LCD-based tiled displays and projection significantly reduces the bezel problem. Our technique eliminates ambiguities that commonly occur on tiled displays in the fields of information visualization, visual data analysis, human-computer interaction, and scientific data display. It improves the usability of multimonitor systems by virtually eliminating the bezels. We describe a setup and provide results from an evaluation experiment conducted on a 3 times 3 and on a 10 times 5 tiled display wall.  相似文献   
89.
Zhao Y  Smith JT  Appenzeller J  Yang C 《Nano letters》2011,11(4):1406-1411
Appropriately controlling the properties of the Si shell in Ge/Si core/shell nanowires permits not only passivation of the Ge surface states, but also introduces new interface phenomena, thereby enabling novel nanoelectronics concepts. Here, we report a rational synthesis of Ge/Si core/shell nanowires with doped Si shells. We demonstrate that the morphology and thickness of Si shells can be controlled for different dopant types by tuning the growth parameters during synthesis. We also present distinctly different electrical characteristics that arise from nanowire field-effect transistors fabricated using the synthesized Ge/Si core/shell nanowires with different shell morphologies. Furthermore, a clear transition in the modification of device characteristics is observed for crystalline shell nanowires following removal of the shell using a unique trimming process of successive native oxide formation/etching. Our results demonstrate that the preferred transport path through the nanowire structure can be modulated by appropriately tuning the growth conditions.  相似文献   
90.
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