全文获取类型
收费全文 | 750篇 |
免费 | 26篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 36篇 |
综合类 | 1篇 |
化学工业 | 151篇 |
金属工艺 | 27篇 |
机械仪表 | 8篇 |
建筑科学 | 18篇 |
能源动力 | 28篇 |
轻工业 | 53篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 72篇 |
一般工业技术 | 129篇 |
冶金工业 | 180篇 |
原子能技术 | 13篇 |
自动化技术 | 58篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 14篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 16篇 |
2015年 | 12篇 |
2014年 | 17篇 |
2013年 | 35篇 |
2012年 | 22篇 |
2011年 | 27篇 |
2010年 | 25篇 |
2009年 | 32篇 |
2008年 | 28篇 |
2007年 | 21篇 |
2006年 | 17篇 |
2005年 | 25篇 |
2004年 | 29篇 |
2003年 | 19篇 |
2002年 | 18篇 |
2001年 | 13篇 |
2000年 | 17篇 |
1999年 | 15篇 |
1998年 | 81篇 |
1997年 | 44篇 |
1996年 | 32篇 |
1995年 | 15篇 |
1994年 | 13篇 |
1993年 | 19篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有777条查询结果,搜索用时 15 毫秒
761.
Doi K Mieno MN Shimada Y Yonehara H Yoshinaga S 《Radiation protection dosimetry》2011,146(1-3):263-267
Cancer risks among childhood cancer survivors following radiotherapy have not yet been well characterised in terms of radiation dose. A meta-analysis of studies on the excess relative risk per gray (ERR) of second cancer was conducted previously; unfortunately, the small number of eligible studies restricted quantitative evaluations. To solve this problem, a statistical method to calculate ERR estimates from other estimates was developed, and a meta-analysis was conducted again. The PubMed database was searched and 26 relevant studies were identified. ERR estimates were available in 15 studies, and for the other 11 studies, the regression-based model was used to calculate ERR estimates from other estimates. The overall ERR estimate was 0.40, which was much lower than that of atomic bomb survivors exposed as young children. Heterogeneity of the risk among studies was suggested, and a further study is needed to explore the heterogeneity among studies. 相似文献
762.
Fanlong Meng Jeff Z. Y. Chen Masao Doi Zhongcan Ouyang 《American Institute of Chemical Engineers》2014,60(4):1393-1399
When a cylindrical balloon is inflated, inflation often takes place nonuniformly, inflated near one end first and followed by the growth of this part along the entire cylinder. This phenomenon is discussed from the phase‐transition perspective in terms of the Gent model, a free‐energy model that has the same structure as that of the gas–liquid transition in normal fluids. A phase diagram which describes the inflation behavior is constructed, showing the binodal and spinodal curves terminated at a critical point. The hysteresis effects are discussed based on the phase diagram. The interface between the coexisting inflated and weakly inflated regions along the cylindrical balloon is also examined, and the interfacial thickness and the interfacial energy are numerically calculated. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1393–1399, 2014 相似文献
763.
764.
The Evolutionary Enhancement of Genotype–Phenotype Linkages in the Presence of Multiple Copies of Genetic Material 下载免费PDF全文
765.
Kamiya N Doi S Tanaka Y Ichinose H Goto M 《Journal of Bioscience and Bioengineering》2007,104(3):195-199
Covalent and site-specific protein immobilization catalyzed by microbial transglutaminase (MTG) was investigated using recombinant Escherichia coli alkaline phosphatase (AP) tagged with a glutamyl donor substrate peptide (MLAQGS) of MTG. A polystyrene surface physically coated with beta-casein or bovine serum albumin (BSA) was employed as an MTG-specific surface displaying reactive lysine residues. MTG-mediated protein immobilization through catalytic varepsilon-(gamma-glutamyl)lysine bond formation between the peptide tag of recombinant APs and beta-casein- or BSA-coated surface was verified by the detection of AP activity on the surface. It was found that the length and the insertion position of the peptide tag did not significantly affect the efficacy of enzymatic immobilization of the recombinant APs. On the other hand, pH and ionic strength in the reaction media had crucial effects on the immobilization yields. Interestingly, the optimum pH range of MTG-mediated protein immobilization differed markedly from that for an MTG-catalyzed reaction in aqueous solution. The results suggest that the concentration of reactive species due to electrostatic interaction between the enzyme-substrate intermediate and the protein-adsorbed surface is a key factor governing MTG catalysis at a solid surface. 相似文献
766.
Takayuki Harada Isao Ohkubo Mikk Lippmaa Yasuaki Sakurai Yuji Matsumoto Shunsuke Muto Hideomi Koinuma Masaharu Oshima 《Advanced functional materials》2012,22(21):4471-4475
A high‐performance spin filter tunnel junction composed of an epitaxial oxide heterostructure is reported. By independently controlling the magnetic orientations of ferromagnetic tunnel barrier and electrode layers, a tunnel magnetoresistance ratio exceeding 120% is obtained purely by the spin filtering effect. A newly introduced spin filter material, Pr0.8Ca0.2Mn1‐yCoyO3, is shown to be useful for building novel multibarrier spintronic tunnel devices due to its composition‐controlled magnetic hardness. 相似文献
767.
Kimata K Yamaguchi M Saito Y Hata H Miyake K Yamane T Nakagawa Y Yano A Ito K Kawarasaki Y 《Journal of Bioscience and Bioengineering》2012,113(2):154-159
Yeast's extracellular expression provides a cost-efficient means of producing industrially useful recombinant proteins. However, depending on the protein to be expressed, the production results in a poor yield, which is occasionally accompanied with loss of the expression plasmid and hence hampered growth of the host in the inducing medium. Here we propose an alternative approach, high cell-density expression, to improve the yield of a certain range of so-called difficult-to-express proteins. In this expression system, recombinant yeast cells resting in stationary phase (OD(660)=3-4) are suspended in a small aliquot of inducing medium to form a high cell-density culture (e.g., OD(660)=15). When applied to the yeast strains harboring Lentinula edodes laccase (Lcc1 or Lcc4) expressing plasmids, the high cell-density system allowed the host cells to synthesize elevated amounts of the laccase which resulted in >1000- to 6000-fold higher yield than those synthesized in a classical growth-associated manner. The resting cells required aerobic agitation for the maximum production. The production system also worked for other foreign enzymes but not for beta-galactosidase from Aspergillus oryzae or Escherichia coli, likely suggesting an involvement of chaperons that act on a certain range of secretory proteins. 相似文献
768.
Masaru Matsumoto Hisato Matsumiya Shinya Fujiwara Yasuaki Ito 《Journal of Wind Engineering & Industrial Aerodynamics》2010,98(8-9):429-437
This paper studies the coupled flutter mechanism of plate and long span bridges based on step-by-step analysis (SBS). Fundamental flutter modes are defined based on amplitude ratio and phase difference between heaving and torsional motions. Furthermore, a formula remarkably similar to the Selberg formula can be derived by use of the particular simplified flutter-onset condition. In the process of SBS analysis, some torsional divergent velocities where the torsional rigidity becomes zero can be defined. Finally, the flutter-behavior of an elastic model of the complete Akashi-Kaikyo Bridge, which is the longest suspension bridge in the world, is studied from the point of view of flutter in 2 degrees of freedom, namely heaving and torsional motion, taking into account the structural coupling effect of additional torsional displacement induced by horizontal displacement as a structural coupling property. 相似文献
769.
Water/Oil Emulsions Prepared by the Membrane Emulsification Method and Their Stability 总被引:2,自引:0,他引:2
We developed and tested a simple method to measure dispersed droplet size of W/O emulsions. Then, using a microporous glass membrane treated with oil phase, we produced a W/O emulsion with high water content (40% w/w) at a high emulsification rate by the membrane emulsification method, and assessed its stability. In comparison with emulsions by the stirring methods, variations in dispersed droplet size and viscosity of emulsions by membrane method were small and the emulsions were more stable. Droplet size was not related to the stability of the W/O emulsion prepared by membrane emulsification. 相似文献
770.