全文获取类型
收费全文 | 1134篇 |
免费 | 31篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 75篇 |
综合类 | 6篇 |
化学工业 | 339篇 |
金属工艺 | 58篇 |
机械仪表 | 33篇 |
建筑科学 | 33篇 |
矿业工程 | 2篇 |
能源动力 | 46篇 |
轻工业 | 74篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 86篇 |
一般工业技术 | 165篇 |
冶金工业 | 94篇 |
原子能技术 | 59篇 |
自动化技术 | 91篇 |
出版年
2022年 | 7篇 |
2021年 | 20篇 |
2020年 | 6篇 |
2019年 | 17篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 24篇 |
2015年 | 14篇 |
2014年 | 36篇 |
2013年 | 66篇 |
2012年 | 34篇 |
2011年 | 70篇 |
2010年 | 55篇 |
2009年 | 58篇 |
2008年 | 49篇 |
2007年 | 69篇 |
2006年 | 48篇 |
2005年 | 52篇 |
2004年 | 34篇 |
2003年 | 45篇 |
2002年 | 32篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 23篇 |
1998年 | 41篇 |
1997年 | 18篇 |
1996年 | 24篇 |
1995年 | 21篇 |
1994年 | 19篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1984年 | 18篇 |
1983年 | 18篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1972年 | 3篇 |
排序方式: 共有1168条查询结果,搜索用时 31 毫秒
1.
2.
F Chen M Murata Y Hiraku N Yamashita S Oikawa S Kawanishi 《Canadian Metallurgical Quarterly》1998,29(3):197-205
We have previously reported that long-term priming of human polymorphonuclear neutrophilic granulocytes (PMN) with interferon-gamma (IFN-gamma) increased the fMLP-stimulated calcium influx. We now show that also after short-term incubation with IFN-gamma, PMN calcium metabolism is modulated. Single adherent cells in three different calcium-containing buffers (high, normal, and low [Ca2+]) were stimulated with the bacterial peptide fMLP or the Ca-ATPase inhibitor thapsigargin (Tg) after about 5 min preincubation with IFN-gamma. The results of this protocol indicated that IFN-gamma increases both calcium influx and calcium sequestration. Store dependent Ca2+ influx, directly measured on readdition of calcium to Tg-treated cells incubated in EGTA buffer, was significantly enhanced in IFN-gamma-treated cells. This effect of IFN-gamma was enhanced by the tyrosine kinase inhibitor herbimycin A. Strikingly, in low extracellular calcium concentrations, IFN-gamma induced calcium transients in 20%-60% of the cells. The proportion of PMN responding with Ca2+ transients increased with decreasing extracellular calcium concentration. Average lagtime from addition of IFN-gamma to a response that could be measured was 7.3 sec, and average increase in [Ca2+] above the basal level was 790 nM. These IFN-gamma-induced transients could not be depressed by herbimycin A. Thus, IFN-gamma can increase capacitative calcium influx, induce calcium transients, and possibly affect calcium sequestration in human PMN. 相似文献
3.
4.
5.
X. J. Liu R. Kainuma I. Ohnuma K. Ishida K. Oikawa 《JOM Journal of the Minerals, Metals and Materials Society》2003,55(12):53-59
Phase diagrams and a thermodynamic database constructed by the Calculation of Phase Diagrams approach offer powerful tools
for alloy design and materials development. This article presents recent progress on the thermodynamic database for microsolders
and copper-based alloys, which is useful for the development of lead-free solders and prediction of interfacial phenomena
between solders and the copper substrate in electronic packaging technology. In addition, examples of phase diagram applications
are presented to facilitate the development of Co-Cr-based magnetic recording media in hard disks and new ferromagnetic shape-memory
alloys.
For more information, contact K. Ishida, Tohoku University, Department of Materials Science, Graduate School of Engineering,
Aoba-yama 02, Sendai 980-8579, Japan. 相似文献
6.
Kazuyoshi Kataoka Kazuo Furuta Yoshiaki Oka Shunsuke Kondo 《Nuclear Engineering and Design》1988,110(1)
Transmutation of neptunium, which is contained in radioactive wastes discharged from nuclear reactors, was investigated as a substitutional method for geologic disposal. We proposed a transmutation reactor fueled with a mixture of gaseous 233UF6 and 237NpF6. Neutronic and thermodynamic analysis of the reactor revealed the feasibility of the concept. The reactor has two principal advantages: (1) use of the fuel gas enables on-line reprocessing, (2) 237Np can be transmuted by a high neutron flux. Our calculation indicated that the transmutation rate of 237Np was 335 g/year/MWth, which is much larger than the annual yield of 232Np in PWR (6.19 g/year/MWth). 相似文献
7.
Lipid-Lowering Effect of Eriocitrin, the Main Flavonoid in Lemon Fruit, in Rats on a High-Fat and High-Cholesterol Diet 总被引:2,自引:0,他引:2
Yoshiaki Miyake Eriko Suzuki Satoko Ohya Syuichi Fukumoto Masanori Hiramitsu Kazuhiro Sakaida Toshihiko Osawa Yukio Furuichi 《Journal of food science》2006,71(9):S633-S637
ABSTRACT: Eriocitrin (eriodictyol 7- O -β-rutinoside) is the main flavonoid in lemon fruit. In this study, eriocitrin was investigated for its lowering effect on serum and hepatic lipids in high-fat and high-cholesterol fed rats. Rats in the control group ( N = 6) were fed a 20% lard and 1% cholesterol diet for 21 d, and rats in the 0.35% eriocitrin group ( N = 6) and 0.70% eriocitrin group ( N = 6) were fed a diet supplemented with eriocitrin 0.35% and 0.70%, respectively. The content of hepatic total cholesterol and triglyceride in the eriocitrin group was no different from that of the control group. The total cholesterol, VLDL+LDL, triglyceride, and phospholipid in the serum of the 0.35% eriocitrin group showed significantly lower concentrations than the control group ( P < 0.05), although there was no difference in the HDL concentrations among the groups. The lowering effect of eriocitrin for serum total cholesterol was thought to be caused by a decrease in VLDL+LDL. The 0.35% eriocitrin group was shown to have a significant increase in excretion of fecal bile acid ( P < 0.05) and a tendency for enhanced hepatic m-RNA levels of LDL receptor in comparison with the control group. 相似文献
8.
Tsuyoshi Takahashi Masahito Kitou Michio Asai Mitsuyasu Kido Tomio Chiba Junzou Kawakami Yoshiaki Matsui 《Electrical Engineering in Japan》1994,114(2):18-33
Power system control equipment needs higher sensitivity and operational reliability. Advanced voltage control equipment is needed for reducing the frequency of tap changes and improving the characteristics (the relationship between the actual voltage and reference voltage) of the voltage to meet today's power system requirements. However, these objectives are in a trade-off relationship. Studies of voltage control derived from a knowledge base suitable for electric power systems can satisfy these objectives using fuzzy inference. Compared with corresponding conventional equipment, the new equipment improved the deviation of 30 min average voltage of 30 percent. This paper describes the design concept of new voltage control equipment using fuzzy inference. In addition, field test results are described along with rules of fuzzy inference, membership functions, and the deviation of 30 min average voltage through detailed simulation. 相似文献
9.
Hideaki Yamada Akiyoshi Chayahara Yoshiaki Mokuno Shin-ichi Shikata 《Diamond and Related Materials》2008,17(4-5):494-497
A new structure of microwave plasma for chemical vapor deposition of diamond crystal is proposed. The structure is designed numerically, for which an improved model given in our previous work [H. Yamada et al., J. Appl. Phys. 101 (2007), art. no. 063302.] is utilized. The experimental observations and numerical predictions agree well with each other. It is demonstrated experimentally that the proposed structure can achieve a growth rate larger than 50 μm/h over an area 1 in. in diameter. 相似文献
10.
Constant stress creep under compression stress, 100 to 316 MPa, at 1100 K was investigated on single-phase TiAl intermetallics. The material was ingot-cast, isothermally forged, and then annealed to produce stable equi-axed grain structures, whose average grain diameters were 25, 42 and 70m. Creep curves were very similar among the three specimens with different grain diameters and the creep rates at a given strain, as well as the minimum creep rates, depended little on grain size. Two regimes were observed on the stress dependence of the minimum creep rate. The stress exponent under high stresses was about 4.5, independent of grain size. Under stresses lower than about 150 MPa it became about 8. 相似文献