全文获取类型
收费全文 | 1023篇 |
免费 | 32篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 136篇 |
金属工艺 | 10篇 |
机械仪表 | 20篇 |
建筑科学 | 83篇 |
矿业工程 | 8篇 |
能源动力 | 21篇 |
轻工业 | 96篇 |
水利工程 | 4篇 |
石油天然气 | 4篇 |
无线电 | 131篇 |
一般工业技术 | 143篇 |
冶金工业 | 74篇 |
原子能技术 | 1篇 |
自动化技术 | 320篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 33篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 27篇 |
2017年 | 32篇 |
2016年 | 35篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 73篇 |
2012年 | 72篇 |
2011年 | 83篇 |
2010年 | 60篇 |
2009年 | 68篇 |
2008年 | 72篇 |
2007年 | 67篇 |
2006年 | 58篇 |
2005年 | 44篇 |
2004年 | 33篇 |
2003年 | 23篇 |
2002年 | 34篇 |
2001年 | 18篇 |
2000年 | 11篇 |
1999年 | 13篇 |
1998年 | 14篇 |
1997年 | 13篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 3篇 |
排序方式: 共有1057条查询结果,搜索用时 0 毫秒
41.
Mrityunjay K. Singh Tae G. Kang Patrick D. Anderson Han E. H. Meijer Andy N. Hrymak 《American Institute of Chemical Engineers》2009,55(9):2208-2216
Various designs of the so called Low-Pressure Drop (LPD) static mixer are analyzed for their mixing performance using the mapping method. The two types of LPD designs, the RR and RL type, show essentially different mixing patterns. The RL design provides globally chaotic mixing, whereas the RR design always yields unmixed regions separated by KAM boundaries from mixed regions. The crossing angle between the elliptical plates of the LPD is the key design parameter to decide the performance of various designs. Four different crossing angles from 90° to 160° are used for both the RR and RL designs. Mixing performance is computed as a function of the energy to mix, reflected in overall pressure drop for all designs. Optimization using the flux-weighted intensity of segregation versus pressure drop proves the existence of the best mixer with an optimized crossing angle. The optimized angle proves to be indeed the LLPD design used in practice: the RL-120 with θ = 120°, although RL-140 θ = 140° performs as good. Shear thinning shows minor effects on the mixing profiles, and the main optimization conclusions remain unaltered. © 2009 American Institute of Chemical Engineers AIChE J, 2009 相似文献
42.
George Kontopidis Dr. Martin J. Andrews Dr. Campbell McInnes Dr. Andy Plater Dr. Lorraine Innes Scott Renachowski Dr. Angela Cowan Peter M. Fischer Prof. 《ChemMedChem》2009,4(7):1120-1128
Peptides that inhibit cyclin‐dependent kinase 2 by blocking the macromolecular substrate recruitment site of cyclin A were simplified, for example, by replacement of dipeptide units with β‐amino acids. The smallest inhibitor retaining activity was a tripeptide, whose binding mode was confirmed by X‐ray crystallography. This result suggests that nonpeptidic cyclin groove inhibitors may be feasible therapeutic agents.
43.
Rajangam Udayakumar Sampath Kasthurirengan Thankaraj Salammal Mariashibu Manoharan Rajesh Vasudevan Ramesh Anbazhagan Sei Chang Kim Andy Ganapathi Chang Won Choi 《International journal of molecular sciences》2009,10(5):2367-2382
Withania somnifera is an important medicinal plant, which is used in traditional medicine to cure many diseases. Flavonoids were determined in the extracts of W. somnifera root (WSREt) and leaf (WSLEt). The amounts of total flavonoids found in WSREt and WSLEt were 530 and 520 mg/100 g dry weight (DW), respectively. Hypoglycaemic and hypolipidaemic effects of WSREt and WSLEt were also investigated in alloxan-induced diabetic rats. WSREt and WSLEt and the standard drug glibenclamide were orally administered daily to diabetic rats for eight weeks. After the treatment period, urine sugar, blood glucose, haemoglobin (Hb), glycosylated haemoglobin (HbA1C), liver glycogen, serum and tissues lipids, serum and tissues proteins, liver glucose-6-phosphatase (G6P) and serum enzymes like aspartate transaminase (AST), alanine transaminase (ALT), acid phosphatase (ACP) and alkaline phosphatase (ALP) levels were determined. The levels of urine sugar, blood glucose, HbA1C, G6P, AST, ALT, ACP, ALP, serum lipids except high density lipoprotein-bound cholesterol (HDL-c) and tissues like liver, kidney and heart lipids were significantly (p < 0.05) increased, however Hb, total protein, albumin, albumin:globulin (A:G) ratio, tissues protein and glycogen were significantly (p < 0.05) decreased in alloxan-induced diabetic rats. Treatment of the diabetic rats with WSREt, WSLEt and glibenclamide restored the changes of the above parameters to their normal level after eight weeks of treatment, indicating that WSREt and WSLEt possess hypoglycaemic and hypolipidaemic activities in alloxan-induced diabetes mellitus (DM) rats. 相似文献
44.
Brominated isobutylene‐co‐p‐methylstyrene (BIMS) rubber has been blended with hydrocarbon resin tackifier and alkyl phenol formaldehyde resin tackifier, and the compatibility between the blend components has been systematically evaluated. Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) studies show that BIMS rubber and hydrocarbon resin tackifier blends are compatible at all blend proportions studied. However, BIMS rubber and phenol formaldehyde resin blends exhibit very limited compatibility with each other and phase separation even at very low phenolic tackifier concentration. Morphological studies of the rubber–resin blends by scanning electron microscopy (SEM) corroborate well with the DMA and DSC results. From the DMA frequency sweep and temperature sweep studies, it is shown that the hydrocarbon resin tackifier acts as a diluent and causes a decrease in the storage modulus values (by reducing the entanglement and network density) in the rubbery plateau region. On the other hand, phenol formaldehyde resin behaves in the way similar to that of the reinforcing filler by increasing the storage modulus values (by increasing the entanglement and network density) in the rubbery plateau zone. The relaxation time estimated from the different zones of frequency sweep master curves provides information about the influence of the two tackifiers on the viscoelastic properties of the BIMS rubber in the respective zones. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
45.
Co-combustion of chicken litter (CL) with coal was performed in a laboratory-scale fluidized bed combustor to investigate the effect of CL combustion on pollutant emissions. The emissions of major gaseous pollutants including CO, SO2, H2S and NO and temperature distribution along the combustor were measured during the tests. Effects of CL fraction and secondary air on combustion characteristics were studied. The experimental results show that CL introduction increases CO emissions and reduces the levels of SO2. The ratio of H2S/SO2 increases with increasing fraction of CL. NO emissions either increase or decrease depending on the percentage of CL in the mixed fuels. The temperature in the freeboard region increases with increasing the fraction of CL while the reverse is true for the bed temperature. 相似文献
46.
K. Dinesh Kumar Sanjiv Gupta B.B. Sharma Andy H. Tsou Anil K. Bhowmick 《Polymer Engineering and Science》2008,48(12):2400-2409
The viscoelastic behavior of brominated isobutylene‐co‐p‐methylstyrene (BIMS) rubber/hydrocarbon resin blends and BIMS/phenol formaldehyde resin blends was studied with the use of a rubber process analyzer. Dynamic mechanical analysis and scanning electron microscopy were used to evaluate the compatibility between the BIMS/tackifier blends. Strain sweep tests at temperature below the softening point of the tackifiers showed the formation of resin–resin networks in the incompatible BIMS/phenolic resin blends. However, resin–resin network was not prominent in the case of the compatible BIMS/hydrocarbon resin blends. Frequency sweep tests were performed at the strain amplitude within the linear region at several temperatures and the variations of shear storage modulus, G′ and complex viscosity, η* against frequency were recorded. The tackifying resins modified the viscoelastic properties of the BIMS rubber by reducing the storage modulus at lower frequency and by increasing the storage modulus at higher frequencies. However, this action was found to be highly dependent on (a) rubber‐tackifier compatibility, (b) blend proportions, and (c) test temperature. Furthermore, stress relaxation measurements of the BIMS/tackifier blends at temperature below the softening point of the tackifiers showed longer period of relaxation for the incompatible BIMS/phenolic resin blends. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers 相似文献
47.
48.
在上期的报告中,我们谈到用户越来越多地集中资源.将文件应用程序和跨媒体互动(CMI)组合在一起。在本期的评论中,我们要探讨企业对跨媒体互动如此感兴趣的原因.跨媒体互动的兴起,以及跨媒体互动正在对印刷行业产生的积极影响。 相似文献
49.
Knowledge of explosives sorption and transformation processes is required to ensure that the proper fate and transport of such contaminants is understood at military ranges and ammunition production sites. Bioremediation of 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and related nitroaromatic compounds has met with mixed success, which is potentially due to the uncertainty of how energetic compounds are bound to different soil types. This study investigated the dissolution and sorption properties of TNT and RDX explosives associated with six different soil types. Understanding the associations that explosives have with a different soil type assists with the development of conceptual models used for the sequestration process, risk analysis guidelines, and site assessment tools. In three-way systems of crystalline explosives, soil, and water, the maximum explosive solubility was not achieved due to the sorption of the explosive onto the soil particles and observed production of transformation byproducts. Significantly different sorption effects were also observed between sterile (gamma-irradiated) and nonsterile (nonirradiated) soils with the introduction of crystalline TNT and RDX into soil-water systems. 相似文献
50.