全文获取类型
收费全文 | 823篇 |
免费 | 22篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 52篇 |
综合类 | 3篇 |
化学工业 | 242篇 |
金属工艺 | 26篇 |
机械仪表 | 17篇 |
建筑科学 | 23篇 |
能源动力 | 34篇 |
轻工业 | 93篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 52篇 |
一般工业技术 | 185篇 |
冶金工业 | 33篇 |
原子能技术 | 22篇 |
自动化技术 | 64篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 13篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 22篇 |
2015年 | 22篇 |
2014年 | 21篇 |
2013年 | 42篇 |
2012年 | 42篇 |
2011年 | 50篇 |
2010年 | 46篇 |
2009年 | 43篇 |
2008年 | 60篇 |
2007年 | 47篇 |
2006年 | 32篇 |
2005年 | 34篇 |
2004年 | 24篇 |
2003年 | 34篇 |
2002年 | 28篇 |
2001年 | 28篇 |
2000年 | 20篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 16篇 |
1995年 | 7篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1969年 | 3篇 |
排序方式: 共有853条查询结果,搜索用时 15 毫秒
41.
Seiji Shiromoto Yasushi Masutani Masaaki Tsutsubuchi Yoshiaki Togawa Toshihisa Kajiwara 《Polymer Engineering and Science》2010,50(1):22-31
In this study, the experiment of the extrusion lamination process using high‐pressure process low‐density polyethylene (LDPE) was performed. The nonisothermal viscoelastic simulation of the extrusion lamination experiment was also carried out. The simulation results were in good agreement with the experimental data within wide range of take up velocity and air gap length. We developed the theoretical model based on force balance and deformation type of a film to predict the neck‐in behavior in the extrusion lamination or cast film process. It was suggested from the neck‐in model that the neck‐in correlates with the ratio of planar to uniaxial elongational viscosity. It was confirmed that the neck‐in model could predict the film edge shape and neck‐in properly for conventional LDPE. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers 相似文献
42.
Isobe K Shoji K Nakanishi Y Yokoe M Wakao N 《Journal of Bioscience and Bioengineering》2003,95(3):257-263
Cholesterol oxidase (CHO) with high stability in detergents was found from an isolated strain, Y-134, belonging to the gamma-subclass of Proteobacteria. CHO production reached its maximum by incubation at 30 degrees C for 12 d. It was purified from cell-free extract prepared by mixing the cells with 0.4% Triton X-100. The absorption spectrum of the purified enzyme exhibited maxima at 274 and 410 nm, and a shoulder at 330 nm. The molecular mass was 115 kDa with two identical subunits of 58 kDa. The enzyme oxidized cholest-5-en-3beta-ol (cholesterol) and 5alpha-cholestan-3beta-ol (dihydrocholesterol) at a high reaction rate, and the K(m) value for cholesterol was 65 microM. The stability of the enzyme was higher than other CHOs in nonionic detergents with high values of hydrophilelipophile balance (HLB) such as Triton X-450 and sodium cholate. NH2-terminal sequence analysis showed a high similarity to CHO from Burkholderia cepacia, but not to CHOs from Streptomyces or Brevibacterium. 相似文献
43.
Higuchi M Miyata D Kawamura S Ueda E Imanaka M Tonogai Y 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2004,45(6):339-343
Daily intakes of 12 phenols which are possible endocrine disruptors were estimated in hospital meals from 2000 to 2001. 4-Nonylphenol (4-NP (mix)) and bisphenol A (BPA) were detected at levels of 5.0 to 19.4 ng/g and 0.2 to 1.1 ng/g, respectively. 4-tert-Butylphenol, 4-n-pentylphenol, 4 -tert-pentylphenol, 4-n-hexylphenol, 4-n-heptylphenol and 4-tert-octylphenol were detected at levels of 0.1 to 2.4 microg/g. The daily intakes of 4-NP (mix) and BPA were 5.8 microg/day and 0.42 microg/day, respectively. The daily intakes of other phenols were less than 1 microg/day. 相似文献
44.
YoonKeun Chae JinWon Park Shinsuke Mori Masaaki Suzuki 《Journal of Industrial and Engineering Chemistry》2012,18(4):1237-1241
The partial reduction of TiO2 was attempted by heat treatment and plasma-heat treatment and it was carried out to investigate the photocatalytic characteristics of partially reduced TiO2 (TiO2?x) in the visible-light region. As a result, the plasma-heat treatment shows significantly stronger than the heat treatment for the visible-light photocatalytic activity of TiO2. The red-shifted absorption bands in the visible-light region of TiO2?x by plasma-heat treatment gave broader than one by heat treatment. The TiO2?x by heat treatment and plasma-heat treatment was changed white to beige color, and white to navy, respectively. 相似文献
45.
Yasuo Kagawa Mami Hiraoka Yukiko Miyashita-Hatano Madoka Shishido-Oki Mamiko Yoshida Susumu Kondou Mika Sugiura Kazumi Sawakami-Kobayashi Masaaki Takahashi Hideji Tajima Masafumi Yohda 《Journal of Bioscience and Bioengineering》2010,110(4):505-508
A low-cost and simple on-site technique for genotyping single nucleotide polymorphisms (SNPs) was developed. The technique is based on allele-specific primer PCR and the recently developed bead arrays in a single tip technique. The performance of the method was verified by genotyping four SNPs that correlate with cardiovascular diseases. 相似文献
46.
The reduction of 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4-diisopropyltetrasila-2-yne 1 with an equivalent amount of alkali metal (Li, Na, K, KC8) in THF produced the corresponding disilyne anion radicals 2a–c. Their EPR spectra are independent of the metals used in THF, indicating that the disilyne anion radical species exists as solvent-separated ion pairs in polar solvents. The one-electron reduction also occurred with potassium in toluene to produce the potassium salt of the anion radical 3, which was isolated as extremely air- and moisture-sensitive dark brown crystals. The molecular structure of 3 was established by X-ray crystallography, which showed that the potassium ion is solvated by one toluene molecule. The EPR spectrum of 3 in toluene showed the interaction of the anionic silicon atom with the K+ ion. 相似文献
47.
Shingo Hirose Akihiro Yoshida Masaaki Yamaura Nobuo Kano Hiro Munekata 《Journal of Materials Science: Materials in Electronics》2000,11(1):7-10
We demonstrate a method for successfully controlling carbon incorporation in AlAs layers grown by atomic layer epitaxy (ALE) using various GaAs substrates with different orientations. The number of alkyl radicals attached to an Al atom at the surface, which is a main factor in carbon incorporation, can be intentionally controlled by changing substrate orientation. We found that the carbon incorporation in ALE-AlAs using the (3 1 1)B surface is 2 x 1017,cm-3, which is the lowest value ever reported for ALE-AlAs that satisfies one-monolayer self-limiting growth conditions. 相似文献
48.
Hitoshi Tanaka Morimasa Tanimoto Akira Matsuda Takeo Uno Masaaki Kurihara Shoji Shiga 《Journal of Electronic Materials》1999,28(11):1216-1223
Pb-free solderable surface finishing is essential to implement Pb-free solder assembly in order to meet with the growing demand
of environmental consciousness to eliminate Pb from electronic products. Two types of widely applicable Pb-free surface finishing
technologies are developed. One is the multilayer-system including Pd with Ni undercoat. Heat-resistance of Pd enables whole-surface-plating
on to leadframe before IC-assembling process. The other is the double-layer-system with low-melting-point-materials, for example,
thicker Sn underlayer and thinner Sn-Bi alloy overlayer, dilutes Sn-Bi alloy’s defects of harmful reactivity along with substrate
metal and mechanical brittleness with keeping its advantages of solder-wettability and no whisker. 相似文献
49.
50.
Wei Zhang Kenji Ochi Michiya Fujiki Masanobu Naito Masaaki Ishikawa Kei‐ichi Kaneto Wataru Takashima Akinori Saeki Shu Seki 《Advanced functional materials》2010,20(22):3941-3947
In this paper a simple, casting solution technique for the preparation of two‐dimensional (2D) arrays of very‐high molecular weight (MW) 1D‐Pc supramolecular inorganic polymers is described. The soluble fluoroaluminium tetra‐tert‐butylphthalocyanine (ttbPcAlF) is synthesized and characterized, which can be self‐assembled to form 2D arrays of very‐high‐MW 1D‐Pc supramolecular inorganic polymers. High‐resolution transmission electron microscopy (HRTEM) demonstrates that the 1D‐ttbPcAlF, having a cofacial ring spacing of ~0.36 nm and an interchain distance of ~1.7 nm, self‐assembles into 2D‐nanosheets (~140 nm in length, ~20 nm in width, and equivalent to MW of 3.2 × 105 g mol?1). The film cast from a 1,2‐dichloroethane (DCE) solution shows a minimum hole‐mobility of ~0.3 cm2 V?1 s?1 at room temperature by flash‐photolysis time‐resolved microwave conductivity (TRMC) measurements and a fairly high dark dc‐conductivity of ~1 × 10?3 S cm?1. 相似文献