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   352篇
  免费   25篇
  国内免费   1篇
电工技术   15篇
综合类   2篇
化学工业   92篇
金属工艺   21篇
机械仪表   8篇
建筑科学   7篇
能源动力   9篇
轻工业   28篇
水利工程   4篇
无线电   27篇
一般工业技术   70篇
冶金工业   34篇
原子能技术   9篇
自动化技术   52篇
  2024年   1篇
  2023年   6篇
  2022年   13篇
  2021年   16篇
  2020年   7篇
  2019年   16篇
  2018年   22篇
  2017年   22篇
  2016年   31篇
  2015年   14篇
  2014年   19篇
  2013年   23篇
  2012年   23篇
  2011年   26篇
  2010年   15篇
  2009年   21篇
  2008年   21篇
  2007年   15篇
  2006年   5篇
  2005年   15篇
  2004年   7篇
  2003年   6篇
  2002年   3篇
  2000年   5篇
  1999年   3篇
  1998年   6篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1982年   1篇
  1980年   1篇
  1976年   1篇
排序方式: 共有378条查询结果,搜索用时 15 毫秒
91.
Phase equilibria and martensitic and magnetic phase transformations of the β phase in the Co−Ni−Ga system have been investigated. It has been shown that the β phase is in equilibrium with the α-phase over a wide range compositions at 600–1100°C. The β phase exhibits both a paramagnetic-ferromagnetic transition and a thermoelastic martensitic transition from B2 to L10 structure. The Curie temperature T C increases with decreases with decreasing Ni content and with increasing Ga content. The composition region of the β phase exhibiting the thermoelatstic martensitic transformation from ferromagnetic austenite is located near the α+β two-phase region. T C and M s of α+β two-phase alloys increase with increasing annealing temperature. This paper was presented at the International Symposium on User Aspects of Phase Diagrams, Materials Solutions Conference and Exposition. Columbus, Ohio, 18–20 October, 2004.  相似文献   
92.
Heat transfer coefficients were measured on tube bundles of fundamental layouts including in‐line layouts embedded horizontally in a liquid‐fluidized bed. Tested tube layouts were single tubes, transverse single tube rows, longitudinal single tube rows, and in‐line arranged tube bundles. A total of 7 kinds of particles were used. Comparisons of the experimental data showed a good agreement with the heat transfer correlation developed for staggered layouts, when the average liquid velocity through each tube bundle was used as the reference velocity for the particle Reynolds number. Distribution of the local heat transfer coefficient was also investigated around tubes. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20245  相似文献   
93.
94.
95.
Accumulation of α-synuclein (α-syn) is the pathological hallmark of α-synucleinopathy. Rapid eye movement (REM) sleep behavior disorder (RBD) is a pivotal manifestation of α-synucleinopathy including Parkinson’s disease (PD). RBD is clinically confirmed by REM sleep without atonia (RWA) in polysomnography. To accurately characterize RWA preceding RBD and their underlying α-syn pathology, we inoculated α-syn preformed fibrils (PFFs) into the striatum of A53T human α-syn BAC transgenic (A53T BAC-SNCA Tg) mice which exhibit RBD-like phenotypes with RWA. RWA phenotypes were aggravated by PFFs-inoculation in A53T BAC-SNCA Tg mice at 1 month after inoculation, in which prominent α-syn pathology in the pedunculopontine nucleus (PPN) was observed. The intensity of RWA phenotype could be dependent on the severity of the underlying α-syn pathology.  相似文献   
96.
Polyelectrolyte polyacrylic acid (PAA), used in the chemical modification of titanium dioxide (TiO(2)) nanoparticles, allows TiO(2) nanoparticles to remain in suspension at neutral pH. The anti-17beta-estradiol (E2) antibody was immobilized on PAA-modified TiO(2) (PAA-TiO(2)) nanoparticles via covalent bonding between the carboxylic acid of PAA and the amino group of the antibody. The anti-E2-antibody-immobilized TiO(2) (E2Ab-PAA-TiO(2)) nanoparticles can form a suspension at neutral pH, with a particle size of less than 100 nm. The E2-PAA-TiO(2) nanoparticles caused the photocatalytic degradation of a typical TiO(2) substrate, methylene blue. The anti-E2 antibody immobilized on the TiO(2) surface recognized and bound E2 in the solution, thereby improving the efficiency of E2 degradation compared with that of PAA-TiO(2) nanoparticles. These results demonstrate that the E2Ab-PAA-TiO(2) nanoparticles developed in this study can be used in water treatment technology. Furthermore, this strategy of immobilizing proteins on nanoscale TiO(2) particles creates new applications not only in the treatment of environmental waste, but also in medical and public sanitation processes.  相似文献   
97.
该文针对摄入醋酸菌对于酒精性肝损伤的影响进行了评价。将C57BL/6J小鼠(8周龄,雄性,22~27 g)分为对照组(非乙醇给药组)、乙醇组(给予2.5 g/kg乙醇)、乙醇+醋酸菌组(给予2.5 g/kg乙醇+10 mg醋酸菌),分别每天给药3次,连续经口给药14 d,测定了血清谷草转氨酶(AST)、谷丙转氨酶(ALT)及肝脏油脂浓度。结果表明,与对照组相比较,乙醇组小鼠的AST与ALT浓度,肝脏甘油三酯与胆固醇浓度显著增高(P<0.05);乙醇+醋酸菌组的数值则显著低于乙醇组(P<0.05)。以上结果表明,摄入醋酸菌有可能会减轻酒精性肝损伤。  相似文献   
98.
In order to enhance the neutron-shielding performance of concrete in neutron-generation facilities from the viewpoint of reduction of effective dose rates in operation and radioactive wastes in decommission, we developed concrete with boron of more than 10 wt%. We performed a neutron-shielding experiment using the mockup of the newly developed boron-loaded concrete and Deuterium Tritium (DT)neutrons at the Fusion Neutronics Source in the Japan Atomic Energy Agency, and measured the reaction rates of 93Nb(n,2n)92mNb and 197Au(n,γ)198Au reactions in the mockup. The calculations were conducted using MCNP-5.14 and FENDL-2.1. The calculation results agreed well with the measured ones, and we confirmed that the accuracy was very good on the atomic composition data of boron-loaded concrete and their nuclear data. In addition, we calculated the neutron and photon effective dose rates and reaction rates of 59Co(n,γ)60Co and 151Eu(n,γ)152Eu reactions, which produce critical radioisotopes in decommission, in boron-loaded concrete and other concretes with DT neutrons, and the experimental condition presently used. The dose rates and reaction rates were drastically reduced by using boron-loaded concrete and it was concluded that boron-loaded concrete had very good shielding performance for DT neutrons.  相似文献   
99.
ABSTRACT

For recent boron neutron capture therapy (BNCT), accelerator-based neutron sources have been actively developed in place of reactor-based neutron sources. In this study, a novel neutron energy spectrometer for the daily quality assurance (QA) of BNCT was designed on the basis of a CsI self-activation method for accelerator-based neutron sources. The spectrometer design was optimized in terms of its energy resolution. To verify its applicability to high-intensity BNCT neutron fields, some practical simulations were performed. It was shown that the designed spectrometer was able to evaluate a neutron energy spectrum in approximately 900 s after an instantaneous neutron irradiation. In addition, its energy resolution was sufficient for detecting an unexpected distortion in the spectrum. The results confirm that the designed spectrometer can be employed for the daily QA of BNCT to check that the expected spectrum remains unchanged.  相似文献   
100.
Artificial Life and Robotics - When using an autonomous mobile robot, an environmental map should be created in advance. In this study, we propose a method for creating a point cloud data (PCD) map...  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