全文获取类型
收费全文 | 285篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 35篇 |
金属工艺 | 36篇 |
机械仪表 | 5篇 |
轻工业 | 1篇 |
石油天然气 | 2篇 |
无线电 | 109篇 |
一般工业技术 | 63篇 |
冶金工业 | 22篇 |
原子能技术 | 3篇 |
自动化技术 | 8篇 |
出版年
2023年 | 3篇 |
2021年 | 3篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2010年 | 7篇 |
2009年 | 4篇 |
2008年 | 11篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 3篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 12篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 6篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 5篇 |
1968年 | 2篇 |
1966年 | 3篇 |
1962年 | 2篇 |
排序方式: 共有287条查询结果,搜索用时 0 毫秒
81.
The results of studies of the radiation characteristics of samples of titanium and alloys thereof in the region of their polymorphous
transformation and the temperature dependence of the emissivity in the β phase are presented. The calorimetric method of electron
heating in high vacuum was used. It is shown that changes in the integral hemispherical emissivity ɛ
th
for titanium iodide and industrial-grade titanium related to the transformation of a hexagonal close-packed lattice into
a body-centered cubic lattice have different characters.
Original Russian Text ? B.A. Shur, V.E. Peletskii, 2009, published in Pribory i Tekhnika Eksperimenta, 2009, No. 1, pp. 162–167. 相似文献
82.
Ciplys D. Rimeika R. Shur M.S. Gaska R. Sereika A. Yang J. Asif Khan M. 《Electronics letters》2002,38(3):134-135
A new solar-blind UV detector based on a GaN surface acoustic wave delay line oscillator is reported. The illumination by an artificial UV source in the presence of sunlight increased the RF spectral line width of the oscillator by almost an order of magnitude, which is attributed to the different noise spectra of these light sources. The output of this detector is a radio signal, which makes it especially attractive for remote sensing applications 相似文献
83.
Shamay-Tsoory Simone G.; Shur Syvan; Harari Hagai; Levkovitz Yechiel 《Canadian Metallurgical Quarterly》2007,21(4):431
Patients with schizophrenia show impaired emotional and social behavior, such as lack of theory of mind and misinterpretation of social situations. However, there is a paucity of work focusing on the empathic abilities of these patients. The present study was designed to examine the degree of impairment in cognitive and affective empathy in schizophrenia and to evaluate the contribution of executive prefrontal functions to empathy in these patients. To explore the neurocognitive processes that underlie the empathic ability in schizophrenic patients, the relationship between empathy scores and the performance on a cognitive flexibility task that assesses dorsolateral and orbitofrontal functioning (set shifting and reversal, respectively) was examined in 26 patients with schizophrenia and 31 healthy control subjects. Results indicated that patients with schizophrenia were significantly impaired in both cognitive and affective empathy compared with healthy control subjects. The degree of impaired empathy related to the severity of negative symptoms. In addition, patients showed impaired performance on measures of both shifting and reversal. However, while cognitive empathy was particularly related to measurements of orbitofrontal (rather than dorsolateral) functioning, affective empathy was related to measures of social functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
84.
Transformation of cellobiose to 3-ketocellobiose by the EDTA-treated Agrobacterium tumefaciens cells
Agrobacterium tumefaciens cells treated with EDTA were used as a biocatalyst for the transformation of cellobiose to 3-ketocellobiose. The effects of pH of the reaction medium and temperature on the reaction rate and the selectivity during the transformation by the cells were examined, and it was found that the optimum reaction conditions were pH 6 and 15 degrees C. The selectivity was about 0.8 under these conditions. The substrate concentration had no significant effect on the selectivity up to 300 mmol/I. 相似文献
85.
A unified analytical charge control model covering the entire range of gate voltages from below and above threshold is developed for heterojunction field-effect transistors (HFETs). This model is based on a new interpretation of the quantized energy levels for the two-dimensional electron gas. It reduces to a classical charge sheet model in the limit of low surface field. The model is used to interpret the experimental data for the subthreshold regime of HFETs. The results indicate wide range variation of the effective acceptor concentration after device fabrication processing in the unintentionally doped GaAs buffer layer 相似文献
86.
M. S. Lewis and P. A. Griffin (see record 1981-21450-001) explained the season of birth effect in schizophrenia in terms of an epidemiological artifact, and they proposed a method of correction for this, based on the hypothesis of an age-prevalence effect. The present authors applied Lewis and Griffin's method in analyzing the birth-month distribution of 11,728 schizophrenic patients first admitted to hospitals in England and Wales between 1970 and 1974. Even when thus corrected, the birth distribution of the schizophrenics remained significantly different from that of the controls. In addition, when July was taken as the 1st mo of the year, the predictions of their hypothesis were not confirmed. It is argued that this hypothesis does not accord with clinical experience and that its consequences cannot be easily reconciled with many of the reported birth distributions of schizophrenia. It is concluded that the age-prevalence effect, as defined by Lewis and Griffin, does not provide any straightforward explanation for the season of birth effect in schizophrenia. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
87.
88.
Drummond T.J. Su S.L. Lyons W.G. Fischer R. Kopp W. Morko? H. Lee K. Shur M.S. 《Electronics letters》1982,18(24):1057-1058
High-performance normally-off modulation-doped (Al,Ga)As/GaAs field-effect transistors with a 1 ?m gate length were fabricated and characterised. The transconductance obtained was 225 mS/mm at 300 K and 400 mS/mm at 77 K, leading to intrinsic transconductances (zero source resistance) of 305 and 565 mS/mm at 300 and 77 K, respectively. Since the device performance in short-gate transistors is limited by the electron saturation velocity, the increasing transconductance observed as the device is cooled is due to an increase in the electron velocity from about 2×107 cm/s to 3×107 cm/s. These velocities are inferred from a model developed for modulation-doped transistors and are predicted by pulse measurements in similar structures. 相似文献
89.
90.