全文获取类型
收费全文 | 303篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 95篇 |
金属工艺 | 19篇 |
机械仪表 | 25篇 |
建筑科学 | 3篇 |
矿业工程 | 1篇 |
能源动力 | 4篇 |
轻工业 | 50篇 |
水利工程 | 4篇 |
石油天然气 | 8篇 |
无线电 | 29篇 |
一般工业技术 | 32篇 |
冶金工业 | 10篇 |
原子能技术 | 2篇 |
自动化技术 | 30篇 |
出版年
2022年 | 7篇 |
2021年 | 6篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 30篇 |
2011年 | 33篇 |
2010年 | 24篇 |
2009年 | 26篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 17篇 |
2005年 | 11篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1983年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有314条查询结果,搜索用时 12 毫秒
11.
Takaaki Tsurumi Young-Bae Kil Kouhei Nagatoh Hirofumi Kakemoto Satoshi Wada Sadayuki Takahashi 《Journal of the American Ceramic Society》2002,85(8):1993-1996
The material coefficients of "soft" and "hard" lead zirconate titanate (PZT) ceramics were determined as complex values by the nonlinear least-squares-fitting of immittance data measured for length-extensional bar resonators. The piezoelectric d -constant should be a complex value to obtain a best fitting between observed and calculated results. Because the elastic, dielectric, and piezoelectric losses determined in this process were not "intrinsic" losses, a calculation process to evaluate the "intrinsic" losses was proposed. It was confirmed that the intrinsic losses were smaller than the corresponding extrinsic losses. The intrinsic piezoelectric loss existed in both soft and hard PZTs; ∼50% of the loss of piezoelectric d -constant was derived from the elastic and dielectric losses. The most notable difference between the soft and hard PZTs was observed in their elastic losses. 相似文献
12.
An in vitro study was performed to determine the potential application of tissue culture in determining allelopathic potentialof Artemisia princeps var.Orientalis (wormwood). Aqueous extracts and volatile substances ofA. princeps var.Orientalis were tested to determine their effects on callus induction and growth of several tested species. Extracts of 5%A. princeps var.Orientalis caused some reduction in concentration, induction, and growth of callus, although they looked normal, whereas the expiants of most receptor plants did not develop callus at higher concentration. Lettuce andEclipta prostrata were the most sensitive species, andA. princeps var.Orientalis was affected by its own extracts. The growth of calluses in MS 121 medium treated with essential oil ofA. princeps var.Orientalis was inhibited, and the degree of inhibition was proportional to the concentration of the essential oil. 相似文献
13.
Field and laboratory studies were conducted to examine the differential phytotoxicity of residues ofArtemisia princeps var.orientalis (wormwood) using various plants as test species. Seedling elongation and dry weights of receptor plants were inversely proportional to the concentration and incubation time of dry leaves ofA. princeps var.orientalis in vermiculite. In seedling growth tests with abandoned field soils (control) and soil underneath wormwood plants (test), the elongation, dry weight, and caloric content of seedlings grown in the soil from under wormwood plants were severely inhibited, thereby suggesting that certain growth inhibitors were released from wormwood and the inhibitor remained in the soil. 相似文献
14.
A new aromatic diamine monomer containing benzoxazole substituents was prepared by a multistep synthesis starting from 1,4‐dibromo‐2,5‐difluorobenzene. The diamine was polymerized with commercial aromatic dianhydride or dicarboxylic acid chloride monomers to provide several different poly(amic acid)s and polyamides with their inherent viscosities in the range of 0.24–0.46 dL/g. Thermal properties of these polymers including thermal imidization of poly(amic acid)s into polyimides were investigated by using FTIR, DSC, and TGA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 178–185, 2004 相似文献
15.
Seung Bum Kil Yannick Augros Yves Leterrier Jan‐Anders E. Mnson Andreas Christel Camille Borer 《Polymer Engineering and Science》2003,43(2):329-343
The rheological properties in solution, in shear and in uniaxial elongation of poly(ethylene terephthalate) (PET) reacted together with hyperbranched polymers (HBPs) were investigated. Two different PET grades, of low and high molecular weights, were compounded with sub‐ to over‐stoichiometric concentrations of HBPs of second and fourth pseudo‐generation, and subsequently subjected to a solid‐state polycondensation (SSP). The formation of microgels, which occurs at high HBP concentration, gave rise to a large increase in melt elasticity and a related decrease in melt strength. At low HBP concentrations, the complex viscosity of the unreacted HBP/PET was considerably reduced, thus demonstrating a lubrication effect of the HBP molecules. During SSP, the intrinsic and shear viscosities exhibited a gradual increase, which was similar for both PET and HBP/PET blends, and was correlated to an increase in molecular weight, through linear‐chain extension and branching reactions. The elongational viscosity of the reactive blends was also increased as a function of reaction time, and this increase was much larger in the case of the HBP/PET blends. A 400% increase in melt strength of the PET was obtained by combining SSP and trace amounts of an HBP of second generation, without any decrease in drawability. 相似文献
16.
Hyo-Song Lee Jin-Yong Kim Jae-Keun Yu In-Sub Kil Duk-Hyun Kim Tae-Jin Lee Young-Woo Rhee 《Korean Journal of Chemical Engineering》2005,22(6):889-893
In this study, we investigated desulfurization abilities and activation energy using TGA for CuO-AgO sorbents calcined at
700 °C. CuO was used as a main active material and AgO was used as an additive material and 25 wt% SiO2 was used as a support material. The desulfurization reaction temperatures were 450 °C, 500 °C, and 550 °C and the regeneration
reaction temperature was 700 °C. From the TGA experiments, the best sulfur loading of CAS1 sorbent containing 1 wt% AgO was
about 14.95 g sulfur/100 g sorbent at 550 °C. The activation energy was calculated by the Chatterjee-Conrad method based on
the TGA experiment. Desulfurization ability and activation energy of sorbent were decreased as the content of AgO increased. 相似文献
17.
A. A. Neborako O. V. Baranov K. A. Koval’skii L. N. Bykova N. R. Kil’deeva 《Fibre Chemistry》2005,37(2):101-104
The possibility of using the method of direct potentiometry with copper-selective electrodes for determining the copper(II) ion content in process solutions in manufacture of cuprammonium fibres was investigated. The pH region of stable operation of copper-selective electrodes and a method for performing measurements in the entire pH range of the solutions was proposed. The described method can be used for determining the copper(II) ion content in the presence of the components of the process solutions in manufacture of cuprammonium fibres.__________Translated from Khimicheskie Volokna, No. 2, pp. 19–21, March–April, 2005. 相似文献
18.
A. V. Mironov O. L. Vedenina G. A. Vikhoreva N. R. Kil’deeva A. I. Albulov 《Fibre Chemistry》2005,37(1):22-25
Conditions for dry-wet spinning of spherical chitosan granules 0.5–2.0 mm in diameter into a two-layer spinning bath consisting of immiscible liquids are proposed, where an organic liquid, decane in particular, is the upper layer of the bath while a solution of ammonium hydroxide is the lower layer. The possibility of obtaining chitosan microgranules from 2 to 30 µm in diameter by emulsification of a solution of chitosan in decane or a solution of an anion-active surfactant — sodium dodecyl sulfate — is demonstrated. The effect of the molecular weight and concentration of the solutions on the granule-forming power of chitosan is established. A 6% solution of chitosan with a molecular weight of 200 kD is recommended for further studies.__________Translated from Khimicheskie Volokna, No. 5, pp. 26–29, January–February, 2005. 相似文献
19.
Kuk Cho Hankwon Chang Dae Sup Kil Byoung-Gyu Kim Hee Dong Jang 《Journal of Industrial and Engineering Chemistry》2009,15(2):243-246
A one-step grinding process to obtain CaCO3 nanoparticles from a micrometer-sized CaCO3 was studied. A high-speed beads mill was employed to grind the particles, and poly(acrylic acid, sodium salt) was used to disperse the ground particles. The main parameters, which were investigated, were the slurry concentration, the rotor speed, the bead size, and the surfactant concentration. The larger bead size, higher slurry concentration, and faster rotor speed showed higher grinding efficiencies. However, there was severe agglomeration of the ground particles resulting in larger secondary particles as the grinding time increased after the certain point. The dispersion and enhanced grinding of particles were achieved by the surfactant. The particle size distribution of the ground particles had a narrow peak around 190 nm that was measured by the diffraction method. The primary particle size of the ground particles was around 40 nm. 相似文献