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991.
Effect of viscosities of dispersed and continuous phases in microchannel oil-in-water emulsification
Koen van Dijke Isao Kobayashi Karin Schroën Kunihiko Uemura Mitsutoshi Nakajima Remko Boom 《Microfluidics and nanofluidics》2010,9(1):77-85
Although many aspects of microchannel emulsification have been covered in literature, one major uncharted area is the effect
of viscosity of both phases on droplet size in the stable droplet generation regime. It is expected that for droplet formation
to take place, the inflow of the continuous phase should be sufficiently fast compared to the outflow of the liquid that is
forming the droplet. The ratio of the viscosities was therefore varied by using a range of continuous and dispersed phases,
both experimentally and computationally. At high viscosity ratio (η
d/η
c), the droplet size is constant; the inflow of the continuous phase is fast compared to the outflow of the dispersed phase.
At lower ratios, the droplet diameter increases, until a viscosity ratio is reached at which droplet formation is no longer
possible (the minimal ratio). This was confirmed and elucidated through CFD simulations. The limiting value is shown to be
a function of the microchannel design, and this should be adapted to the viscosity of the two fluids that need to be emulsified. 相似文献
992.
An area that has been identified as significantly important in the development of a high temperature reactor (HTR) is the prediction of leakage and bypass flows. It is therefore essential to understand the influence of leakage and bypass flows on the thermal performance of an HTR.A methodology was developed to conduct an integral thermal analysis of a reactor using a CFD approach. One of the main objectives was to include leakage and bypass flow paths in order to provide a capability for simulating these very detailed flows.This paper investigates leakage and bypass flows through the PBMR reactor unit. It was found that, although these flows are dependent on the pressure drop through the pebble bed, a change in pebble bed pressure drop does not result in a similar change in the predicted leakages flows. It is also shown that the ability to account for leakage and bypass flows in an integral manner can help designers to focus their efforts on the specific regions that need to be targeted for the improvement of the life expectancy of the graphite blocks. Furthermore, leakage and bypass flows were found to reduce the pressure drop across the reactor unit while increasing the peak fuel temperatures. 相似文献
993.
Johan Plomp Mikko Heiskanen Mika Hillukkala Tapio Heikkilä Jari Rehu Niek Lambert Victor van Acht Tom Ahola 《International Journal of Wireless Information Networks》2011,18(4):280-294
In this paper, we highlight considerations for synchronization issues in body area networks. Requirements for the synchronization
accuracy in body area networks depend on the application at hand. Synchronization may be needed for power management, sample
ordering, calculation of stimulus responses and for sensor fusion. This paper provides a theoretical exercise to help understand
the accuracy required for typical human motion sensing. It gives an overview of various synchronisation strategies used and
implemented in prototype systems. Lessons learnt from practical implementations using Bluetooth, an IEEE 802.15.4 proprietary
network and Nanonet are presented to illustrate the principles involved. The discussion provides some considerations and the
requirements for typical WBAN applications. 相似文献
994.
995.
996.
Agnès Rortais Jenya Belyaeva Monica Gemo Erik van der Goot Jens P. Linge 《Food research international (Ottawa, Ont.)》2010,43(5):1553-1556
We evaluated the Medical Information System (MedISys) as an early-warning system for the detection of food- and feed-borne hazards. Nine hazards were selected in the period from January 2007 to March 2009 from the Rapid Alert System for Food and Feed (RASFF) and traced back on MedISys and ProMED-mail. In addition, from January to March 2009, food- and feed-borne (re-)emerging hazards were monitored on MedISys and traced back on ProMED-mail and RASFF. MedISys has demonstrated to be an effective early-warning system for food- and feed-borne hazards. However, further customization is required to improve its sensitivity, in particular by increasing the number of multi-lingual categories related to food and feed items. MedISys tended to detect food- and feed-borne hazards earlier and more frequently than ProMED-mail, but the information from both systems was often complementary. 相似文献
997.
Under the “Private Sector Participation in Micro-Hydro Development Project in Rwanda”, four newly registered Rwandan companies are each constructing a micro-hydro electricity plant (100–500 kW) and building a low-voltage distribution grid. These companies financed their plants through their own equity and debt with support from the PSP Hydro project. This support comprised a subsidy of 30–50% of investment costs, technical and business development assistance, project monitoring and financial controlling. The experiences gained so far have important implications for similar future micro-hydro energy sector development projects and this paper puts forward three key messages: (i) institutional arrangements rather than technical quality determine the success of such projects; (ii) truly sustainable rural electrification through micro-hydro development demands a high level of local participation at all levels and throughout all project phases, not just after plant commissioning; and (iii) real impact and sustainability can be obtained through close collaboration of local private and financial sector firms requiring only limited external funds. In short, micro-hydro projects can and will be taken up by local investors as a business if the conditions are right. Applying these messages could result in an accelerated uptake of viable micro-hydro activities in Rwanda, and in the opinion of the authors elsewhere too. 相似文献
998.
999.
Quantifying Biomediated Ground Improvement by Ureolysis: Large-Scale Biogrout Experiment 总被引:2,自引:0,他引:2
Leon A. van Paassen Ranajit Ghose Thomas J. M. van der Linden Wouter R. L. van der Star Mark C. M. van Loosdrecht 《Canadian Metallurgical Quarterly》2010,136(12):1721-1728
Biogrouting is a biological ground improvement method, in which microorganisms are used to induce carbonate precipitation in the subsurface in order to increase the strength and stiffness of granular soils. In this paper the results of a large-scale experiment (100?m3) are presented, in which the feasibility of biogrouting as a ground improvement method is investigated using techniques and equipment similar to those used in potential applications. In situ geophysical measurements were used to monitor the biogrouting process during treatment and indicated that the stiffness had increased significantly after one day of treatment. The results of unconfined compressive strength tests on samples which were excavated after treatment were used to assess the distribution of mechanical properties throughout the cemented sand body, which correlated quite well with the results of the in situ geophysical measurements. The stiffness increase could be quantified as a function of the injected volume of grouting agents and the distance from the injection points. These results will serve as an important benchmark for future applications of biomediated ground improvement. 相似文献
1000.