首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   349篇
  免费   10篇
电工技术   6篇
化学工业   49篇
金属工艺   13篇
机械仪表   9篇
建筑科学   9篇
能源动力   9篇
轻工业   27篇
无线电   66篇
一般工业技术   54篇
冶金工业   73篇
原子能技术   7篇
自动化技术   37篇
  2023年   1篇
  2022年   3篇
  2021年   6篇
  2020年   2篇
  2019年   6篇
  2018年   6篇
  2017年   4篇
  2016年   5篇
  2015年   5篇
  2014年   13篇
  2013年   19篇
  2012年   10篇
  2011年   12篇
  2010年   8篇
  2009年   6篇
  2008年   13篇
  2007年   19篇
  2006年   18篇
  2005年   8篇
  2004年   10篇
  2003年   13篇
  2002年   7篇
  2001年   10篇
  2000年   5篇
  1999年   13篇
  1998年   32篇
  1997年   19篇
  1996年   12篇
  1995年   10篇
  1994年   5篇
  1993年   11篇
  1992年   5篇
  1991年   3篇
  1990年   2篇
  1989年   5篇
  1988年   4篇
  1986年   3篇
  1985年   3篇
  1984年   1篇
  1983年   4篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1977年   3篇
  1976年   3篇
  1975年   4篇
  1973年   1篇
  1967年   1篇
排序方式: 共有359条查询结果,搜索用时 234 毫秒
121.
An analysis of the MOX critical experiments BASALA was performed to verify the pin-by-pin core analysis method using a three-dimensional direct response matrix. The BASALA experiments simulate full MOX BWR cores, and they were carried out in the EOLE critical facility of the French Atomic Energy Commission (CEA) by the Nuclear Power Engineering Corporation (NUPEC) in collaboration with CEA. The BASALA experimental cores are very heterogeneous because their size is much smaller than that of commercial power plants. The main features of the pin-by-pin core analysis method using the three-dimensional direct response matrix are that the response matrix can reflect the intra-assembly heterogeneous effect, the diffusion approximation is not involved, and the fuel rod fission rate can be directly evaluated. The maximum difference of the critical k-effective values among all nine cores analyzed was about 0.4% Δk. The root mean square differences between the calculated and measured radial fuel rod fission rate distributions in the test assembly of all cores were within 1.8% and nearly comparable to measurement error. The calculated results of the reactivity worth agreed with the measured results within 9%. These good agreements mean that the pin-by-pin core analysis method using the three-dimensional direct response matrix accurately reflects the effects of the intra- and inter-assembly heterogeneities in heterogeneous systems like the BASALA experimental cores.  相似文献   
122.
A prototype liquid film sensor for high-temperature steam–water experiments has been developed. The sensor shape simulates a boiling water reactor (BWR) fuel rod. The pulse-echo method can be utilized to measure the thickness of the liquid film covering the sensor surface. A piezoelectric element is soldered onto the inside of the sensor casing which consists of two curved casing pieces. After the piezoelectric element is attached, the two casing pieces are laser welded together. It is confirmed that the temperature rise at the time of the laser welding does not influence soldering of the piezoelectric element. The pressure proof test shows that the sensor can be used at a high-pressure condition of 7 MPa. Simple air–water experiments are done at atmospheric pressure to confirm the liquid film thickness can be measured with the sensor. The fluctuation of the liquid film thickness is satisfactorily captured with the sensor. The minimum and maximum thicknesses are 0.084 and 0.180 mm, respectively. The amplitude of the waveform at 286 °C is predicted by the calculation based on the acoustic impedance. It is expected that the sensor is able to measure the liquid film thickness even at BWR operating conditions.  相似文献   
123.
Reducing CO2 emissions and restraining dependence on nuclear power generation are serious concerns in the prevention of global warming since the Great East Japan Earthquake. To do so, it is necessary to use and expand natural renewable energy source such as solar energy and to promote energy conservation. However, in high-latitude regions, it is difficult to directly and effectively use solar power due to on insufficient amount of solar radiation. If steam can be generated from warm water at less than 373 K, it is possible to obtain steam by solar water heaters from weak solar radiation and industrial waste warm water without the consumption of any fossil fuels. In this study, the authors have been developing a system which generates steam over 423 K from warm water at less than 373 K using an adsorption heat pump with zeolite. Therefore, bench-scale equipment which generates steam continuously and the experimental results are mentioned.  相似文献   
124.
Vortex core transitions (VCTs) in the superfluid phases of liquid 3He in uniaxially stretched and compressed aerogels are theoretically investigated. Uniaxial deformation imposed on the aerogel alters superfluid pairing symmetries in aerogels and the axial and polar pairing states are favored. In this study, we examine whether the effects of the uniaxial anisotropy on the pairing symmetries are reflected in core states of a single vortex extending along the deformation axis. By numerically solving the Ginzburg-Landau equations, we find that in the compressed aerogel, the first order VCT appears at any pressure in the B-like phase, while in the stretched aerogel, the VCT in the B-like phase is lost. Further, the vortices in the A-like phase in the stretched aerogel, have a polar core state in place of the A-phase core of the nonsingular Mermin-Ho vortex.  相似文献   
125.
Inoculation tests of Staphylococcus aureus were performed to evaluate the risk of toxic hazard in cheese manufacturing processes. S. aureus was inoculated into pasteurized milk or cheese curd, and the survival and growth were examined. S. aureus grew only slightly or decreased in cell number under the manufacturing condition of semi-hard type cheese or soft-type cheese. Under the conditions of the fresh cheese making process, S. aureus slightly increased in cell number, though no enterotoxin was detected. In processed cheese, S. aureus did not grow at all. Growth inhibition of S. aureus by lactic acid produced from starter culture was suggested to be the cause of growth inhibition in the natural cheese.  相似文献   
126.
127.
实际设计中,我们将“共享家”设计理念融入“一家三代六口人的生活空间”主题中,将原本两层的空间通过充分利用纵向空间层高变换成四层,在整个大的空间里又让三代人同时拥有自己的独立活动空间.  相似文献   
128.
High-pressure freezing (HPF) has been generally accepted as the most reliable method for cryofixation of biological samples, yielding a deep vitreous freezing. In recent cell biology, mammalian cultured cells are widely used, but HPF of cultured cell monolayer has not reached its full potential. In this study, we developed a new reliable device for HPF of cultured cell monolayer by using a 10-microm-thin stainless disc both as culture plate and specimen carrier. We describe the practical procedure, and demonstrate fine structures of HeLa cells cultured and cryofixed on the stainless discs as results.  相似文献   
129.
Ca3Co4O9 is one of the most promising p-type thermoelectric materials because of its high dimensionless figure of merit ZT. However, polycrystalline Ca3Co4O9 ceramics shows lower ZT value than that for single crystal Ca3 Co4O9 due to its higher electrical resistivity ρ. Mikami et al. have reported that the addition of Ag to Ca3Co4O9 ceramics could successfully reduce ρ and enhance the power factor. On the other hand, Ohtaki et al. reported that a composite structure could be highly effective to reduce κ for ZnO dually doped with Al and Ga. In this work, we tried to enhance the power factor and reduce κ by forming Ca3Co4O9/[Ca2(Co0.65Cu0.35)2O4]0.624CoO2 composite structure. As a result, the ZT value for Ca3Co4O9/[Ca2(Co0.65Cu0.35)2O4]0.624CoO2 composites reached 0.164 at 700 °C, which was 40 % higher than the value for Ca3Co4O9.  相似文献   
130.
Sidebottom et al. have previously shown that one occipitomental 15 degrees view (OM15) is sufficient for screening the majority of cases of midfacial injury. This audit study investigates the effect of introducing a one-view OM15 screening policy into the Accident & Emergency department (A&E) of a district general hospital. Six hundred and twenty-one patients had midfacial radiographic screening over a one-year period. Six hundred and one patients had all notes and radiographs available. Only eight required further views to confirm diagnosis. Thirty-eight fractures were diagnosed with two insignificant fractures of the antral wall missed. The cost saving was Pound Sterling 2082.50 for films alone. Eighty hours of radiographer time were additionally saved. There was no increase in referrals to the maxillofacial team. Single-view radiographic screening for midfacial injuries in A&E attenders is both safe and economical. Extrapolated to the UK population as a whole this would amount to a cost saving to the National Health Service of Pound Sterling 500000.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号