全文获取类型
收费全文 | 114篇 |
免费 | 4篇 |
专业分类
电工技术 | 13篇 |
化学工业 | 31篇 |
机械仪表 | 4篇 |
建筑科学 | 3篇 |
能源动力 | 6篇 |
轻工业 | 5篇 |
无线电 | 8篇 |
一般工业技术 | 34篇 |
冶金工业 | 3篇 |
自动化技术 | 11篇 |
出版年
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2018年 | 4篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 1篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 3篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1983年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有118条查询结果,搜索用时 15 毫秒
31.
The electrochemical properties of two N-hydroxy imides, N-hydroxymaleimide and N-hydroxysuccinimide, at a glassy carbon electrode in acetonitrile were examined by cyclic voltammetry. N-hydroxysuccinimide, which contains no olefinic linkage, indicated a chemically reversible redox response, and its ability as a mediator for the oxidation of benzyl alcohol was confirmed by rotating disk electrode voltammetry. 相似文献
32.
Adrenergic regulation of bone metabolism: possible involvement of sympathetic innervation of osteoblastic and osteoclastic cells 总被引:13,自引:0,他引:13
Togari A 《Microscopy research and technique》2002,58(2):77-84
It has been demonstrated that human osteoblastic as well as osteoclastic cells are equipped with adrenergic receptors and neuropeptide receptors and that they constitutively express diffusible axon guidance molecules that are known to function as a chemoattractant and/or chemorepellent for growing nerve fibers. These findings suggest that the extension of axons of sympathetic and peripheral sensory neurons to osteoblastic and osteoclastic cells is required for the dynamic neural regulation of local bone metabolism. Recently, bone resorption modulated by sympathetic stimulation was demonstrated to be associated with ODF (osteoclast differentiation factor) and OCIF (osteoclastogenesis inhibitory factor) produced by osteoblasts/stromal cells. This review summarizes the evidence implicating sympathetic neuron action in bone metabolism. The possible function of osteoclastogenesis, which could result in the initiation of sympathomimetic bone resorption, is also discussed. 相似文献
33.
Akaratiwa Somchai Nanba Tetsuya Obuchi Akira Okayasu Jun Uchisawa Junko-Oi Kushiyama Satoshi 《Topics in Catalysis》2001,16(1-4):209-216
The selective catalytic reduction by hydrocarbons (HC-SCR) of NO
x
under lean conditions has been improved by the use of double-layered catalysts with a lower layer of Pt/SiO2 and an upper layer of a zeolite such as H-, Ce-, and Cu-ferrierite (-FER). H-FER wash-coated over Pt/SiO2 (H-FER//Pt/SiO2) performed best among the samples examined. The promotional effect was attributed to the synergy of the oxidation catalyst (Pt/SiO2) in converting NO into NO2, which is more reactive to C3H6, and the HC-SCR catalyst (H-FER). Cu-FER//Pt/SiO2 was also effective at widening the temperature window, but with this combination the performance was attributed to a simple summation of the activity of two HC-SCR catalysts that were active at different temperatures. 相似文献
34.
The measurement of tensile modulus of poly(N-isopropylacrylamide) (PNIPA) gel in the solution of NaCl, NaI, LiNO3 and NaNO3 was carried out. It was confirmed that the tensile modulus of PNIPA gel in the solution of salt depends on the volume of gel regardless of the kind and concentration of salts. This result leads us to the conclusion that the addition of salt effect only on the mixing contribution to the Flory's type free energy of gel especially in the swollen state. Therefore, our result is in agreement with a recent remarkable discovery that the volume of PNIPA gel depends only on the chemical potential of water in spite of the kind of additives. On the other hand, it was found that on the volume phase transition point and in the deswollen state, the elasticity of PNIPA gel depended on the concentration and kind of the salt because the viscoelasticity emerged due to the shrinkage of polymer network. 相似文献
35.
A study on flammability limits of fuel mixtures 总被引:1,自引:0,他引:1
Kondo S Takizawa K Takahashi A Tokuhashi K Sekiya A 《Journal of hazardous materials》2008,155(3):440-448
Flammability limit measurements were made for various binary and ternary mixtures prepared from nine different compounds. The compounds treated are methane, propane, ethylene, propylene, methyl ether, methyl formate, 1,1-difluoroethane, ammonia, and carbon monoxide. The observed values of lower flammability limits of mixtures were found to be in good agreement to the calculated values by Le Chatelier's formula. As for the upper limits, however, some are close to the calculated values but some are not. It has been found that the deviations of the observed values of upper flammability limits from the calculated ones are mostly to lower concentrations. Modification of Le Chatelier's formula was made to better fit to the observed values of upper flammability limits. This procedure reduced the average difference between the observed and calculated values of upper flammability limits to one-third of the initial value. 相似文献
36.
Shigeo Kondo Akifumi TakahashiKenji Takizawa Kazuaki Tokuhashi 《Fire Safety Journal》2011,46(5):289-293
Flammability limits of CH2=CFCF3 (HFO-1234 yf), CH2F2 (HFC-32), and methane were measured at pressures from ambient to 2500 kPa in a 5 l stainless-steel spherical vessel. For HFO-1234 yf, as the pressure rises from ambient, the lower flammability limit is shifted downward and the upper limit is shifted upward. The changes to the lower flammability limits are, in general, small compared to the upper flammability limits. Both the lower and upper flammability limits of this compound can be approximated by simple logarithmic functions of pressure. For HFC-32, the behavior of lower flammability limit is similar to that for HFO-1234 yf, but the behavior for the upper limit is rather complicated. As the pressure is increased, it begins to rise upward gradually. Then, as the pressure becomes larger than about 1000 kPa it begins to rise upward rapidly, and then the change becomes moderate again. This must be due to a change of combustion reaction mechanism below 1000 kPa and above 1500 kPa in the upper flammability limit region for this compound. On the other hand, both the flammability limits of methane change almost linearly with pressure, at least in the pressure region considered. 相似文献
37.
一个NT平台上分布式对象数据库服务器系统 总被引:4,自引:0,他引:4
FISH系统是一个用于支持先进应用(如GIS,EC,CIMS)的新一代分布式对象数据库系统.该系统采用了许多新颖技术,如DSVM(distributed shared virtual memory)、持久堆、页式对象、透明锁、紧凑提交等.重点介绍了该系统的总体结构和设计思想,特别是FISH系统在Windows NT上实现所涉及的底层技术,包括内存映射、共享内存、远程过程调用、多线索连接、页面故障处理等.基于OO7的性能测试表明,FISH系统在NT机群环境下取得了与在分布式UNIX环境下同样高的分布执行效率 相似文献
38.
39.
Tatsuki Kitayama Tohru Nishimura Akifumi Oshima Koichi Ute Koichi Hatada 《Polymer Bulletin》1994,32(2):215-222
Summary The effects of stereochemical structure of MMA oligomers on the fragmentation during ionization process in electron-impact ionization and chemical ionization mass spectrometry were studied using the oligomers prepared by stereospecific living oligomerization. The MMA oligomers having t-C4H9-group at the left end and methine proton at the right end showed strong tacticity dependence in their fragmentation process. Fragmentation of MMA tetramer having one head-to-head linkage in the middle of the chain was also studied. 相似文献
40.
R Fukuda N Ishimura Y Kushiyama N Moriyama S Ishihara A Chowdhury A Tokuda S Sakai S Akagi M Watanabe S Fukumoto 《Canadian Metallurgical Quarterly》1996,40(7):481-488
Hepatitis B virus (HBV) with X gene mutations has been a putative pathogen of chronic hepatitis without serological markers of known hepatitis viruses. The aim of this study was to reconfirm whether the HBV with the X gene mutation is associated with these serologically "silent" non-B, non-C (NBNC) chronic hepatitis, alcoholic liver disease (ALD) and autoimmune hepatitis (AIH). HBV DNA was amplified from serum and sequenced in 30 patients with NBNC chronic hepatitis in comparison with 20 patients with ALD and 5 patients with AIH. HBV DNA was identified in 21 patients (70%) in NBNC chronic hepatitis by nested polymerase chain reaction while only one patient (5%) in ALD and none in AIH showed HBV DNA. Eighteen (85.7%) of the 21 identified HBV DNAs had an identical 8-nucleotide deletion mutation at the distal part of the X region. This mutation affected the core promoter and the enhancer II sequence of HBV DNA and created a translational stop codon which truncated the X protein by 20 amino acids from the C-terminal end. All the HBV DNAs had a precore mutation at the 83rd nucleotide resulting in disruption of HBe antigen synthesis. These results indicate that HBV mutants are closely associated with the majority of serologically "silent" NBNC chronic hepatitis cases and the population of such mutant HBV DNAs is not uniform. 相似文献