全文获取类型
收费全文 | 441篇 |
免费 | 24篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 102篇 |
金属工艺 | 29篇 |
机械仪表 | 9篇 |
建筑科学 | 34篇 |
矿业工程 | 2篇 |
能源动力 | 17篇 |
轻工业 | 38篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 15篇 |
一般工业技术 | 83篇 |
冶金工业 | 37篇 |
原子能技术 | 5篇 |
自动化技术 | 87篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 19篇 |
2016年 | 18篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 53篇 |
2012年 | 21篇 |
2011年 | 24篇 |
2010年 | 20篇 |
2009年 | 29篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1971年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有465条查询结果,搜索用时 15 毫秒
41.
Masayoshi Suehiro Zi-Kui Liu John Ågren 《Metallurgical and Materials Transactions A》1998,29(13):1029-1034
The model for the solute drag effect in phase transformations has been applied to recrystallization, i.e., moving grain boundaries. In this model, the total driving force is dissipated by the interfacial energy, the finite interfacial
mobility, the solute drag in boundaries, and diffusion in the matrix ahead of the interface, of which all are taken into account
consistently. The effects of the Gibbs energy of segregation and the diffusivity of impurity atoms in boundaries were investigated.
The results show that the Gibbs energy of segregation mainly affects the critical composition at which the drastic change
in the boundary velocity appears, and the diffusivity of impurity atoms in boundaries mainly affects the velocity reduced
by the solute drag effect. In other words, the Gibbs energy of segregation and the diffusivity of impurity atoms in boundaries
can be evaluated from experimental data by means of the present model. This model was applied to the Al−Mg system, and the
Gibbs energy of segregation and the diffusivity of Mg in boundaries were evaluated from experimental data. The evaluated Gibbs
energy of segregation agrees with the estimate based on elastic energy considerations. The diffusivity estimated from this
model is smaller than that measured along the grain boundary.
ZI-KUI LIU, formerly with the Department of Materials Science and Engineering, Royal Institute of Technology 相似文献
42.
43.
44.
J. J. Ågren O. Hänninen M. Laitinen K. Seppänen I. Bernhardt L. Fogelholm J. Herranen I. Penttila 《Lipids》1988,23(10):924-929
The effect of fish diet on 43 healthy male students was studied. They ate a fish-containing meal for 15 weeks on an average
of 3.7 times per week. Twenty-one of them voluntarily restricted their lipid intake while the rest ate normally. Controls
continued their usual eating habits (19 students). The meals consisted of Finnish freshwater fish (87%) (vendace, pike, perch
and rainbow trout) and brackish water fish (13%) (Baltic herring) that provided about 1 g of ω-3 polyunsaturated fatty acids
per day (0.25 g eicosapentaenoic acid and 0.55 g docosahexaenoic acid). During the diet, ω-3 fatty acids increased in erythrocyte
ghosts and platelets at the expense of ω-6 fatty acids. The concentration of serum cholesterol diminished in those fish consumers
who lowered their lipid intake. Apolipo-protein A1 and B were lowered in both fish-consuming groups. Triglyceride levels also showed a tendency to decrease. The formation of
thromboxane B2 during incubation of whole blood decreased in both fish-consuming groups. The decrease of plasma 6-keto-PGF1α was not statistically significant, if compared with the controls. The results obtained indicate that a moderate intake of
fish-containing meals has some beneficial effects on the plasma lipid and prostanoid metabolism, when coronary heart disease
risk factors are considered. 相似文献
45.
This paper reviews work on self-tuning regulators. The regulator algorithms, their theory and industrial applications are reviewed. The paper is expository—the major ideas are covered but detailed analysis is given elsewhere. 相似文献
46.
Implementation aspects of self-tuning regulators are discussed in the paper. There is a large discrepancy between simulation or academic algorithms and practical algorithms. In the idealized environment of simulations it is easy to get different types of adaptive algorithms to perform well. In practice the situation is quite opposite. The adaptive or self-tuning controller must be able to handle nonlinearities, unmodelled dynamics and unmodelled disturbances over a wide range of operating conditions. Some aspects of how to implement self-tuning controllers are discussed in the paper. This includes robustness, signal conditioning, parameter tracking, estimator wind-up, reset action and start-up. Different ways to use the prior knowledge about the process are also discussed. 相似文献
47.
Gregory R. Hook Ronald J. Elin Jeanette M. Hosseini Carol Swyt Charles E. Fiori 《Journal of microscopy》1986,141(1):69-78
We present a sample preparation method for measuring magnesium in individual whole lymphocytes by electron probe X-ray microanalysis. We use Burkitt's lymphoma cells in culture as the test sample and compare X-ray microanalysis of individual cells with atomic absorption analysis of pooled cell populations. We determine the magnesium peak-to-local continuum X-ray intensity ratio by electron probe X-ray microanalysis and calculate a mean cell magnesium concentration of 39± 19 mmol/kg dry weight from analysis of 100 cells. We determine a mean cell magnesium concentration of 34 ±4 mmol/kg dry weight by atomic absorption analysis of pooled cells in three cell cultures. The mean cell magnesium concentrations determined by the two methods are not significantly different. We find a 10% coefficient of variation for both methods of analysis and a 30% coefficient of variation in magnesium concentration among individual cells by electron probe X-ray microanalysis. We wash cells in ammonium nitrate for microanalysis or in buffered saline glucose for atomic absorption analysis. We find cells washed in either solution have the same cell viability (85%), recovery (75%), cell volume (555 μm3) and cytology. We air dry cells on thin film supports and show by magnesium X-ray mapping that magnesium is within the cells. We conclude that: (a) our microanalysis cell preparation method preserves whole intact lymphocytes; (b) there is no systematic difference in results from the two methods of analysis; (c) electron probe X-ray microanalysis can determine the variation in magnesium concentration among individual cells. 相似文献
48.
B. Åkesson 《Lipids》1980,15(9):677-681
Lipoprotein triacylglycerol secretion was studied in isolated rat hepatocytes incubated with different albumin-bound fatty
acids and labeled glycerol. The release of labeled triacylglycerol was stimulated more by unsaturated fatty acids than by
saturated ones. When lipoprotein secretion was related to cell triacylglycerol synthesis, an effect of unsaturation was no
longer observed. Instead the secretion rate, expressed in this manner, increased with increasing fatty acid chain length.
For the first time, the secretion of molecular species of triacylglycerol has been studied. The distribution of labeled glycerol
among different species was the same in the cells and in the secreted product, indicating that different triacylglycerols
were secreted without selectivity. It is concluded that the fatty acid structure influences lipoprotein triacylglycerol secretion
and it is emphasized that the effects observed depend on the method of quantitation of the secretion rate. 相似文献
49.
Papers in Regional Science - 相似文献
50.