全文获取类型
收费全文 | 1356篇 |
免费 | 37篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 79篇 |
综合类 | 3篇 |
化学工业 | 220篇 |
金属工艺 | 34篇 |
机械仪表 | 24篇 |
建筑科学 | 19篇 |
能源动力 | 54篇 |
轻工业 | 77篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 188篇 |
一般工业技术 | 237篇 |
冶金工业 | 359篇 |
原子能技术 | 20篇 |
自动化技术 | 75篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 35篇 |
2020年 | 9篇 |
2019年 | 18篇 |
2018年 | 26篇 |
2017年 | 22篇 |
2016年 | 30篇 |
2015年 | 22篇 |
2014年 | 29篇 |
2013年 | 44篇 |
2012年 | 45篇 |
2011年 | 63篇 |
2010年 | 45篇 |
2009年 | 64篇 |
2008年 | 62篇 |
2007年 | 55篇 |
2006年 | 45篇 |
2005年 | 37篇 |
2004年 | 32篇 |
2003年 | 23篇 |
2002年 | 26篇 |
2001年 | 23篇 |
2000年 | 21篇 |
1999年 | 44篇 |
1998年 | 117篇 |
1997年 | 80篇 |
1996年 | 40篇 |
1995年 | 36篇 |
1994年 | 28篇 |
1993年 | 28篇 |
1992年 | 13篇 |
1991年 | 24篇 |
1990年 | 21篇 |
1989年 | 13篇 |
1988年 | 24篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 15篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 14篇 |
1975年 | 3篇 |
1972年 | 4篇 |
排序方式: 共有1397条查询结果,搜索用时 31 毫秒
81.
82.
M Sumi H Satoh M Ohtsuka S Hasegawa M Fujiwara H Kamma 《Canadian Metallurgical Quarterly》1998,5(6):1439-1440
Malignant lymphomas arise in the pleura in association with a long-standing chronic tuberculous pyothorax. We report a case of a non-Hodgkin's lymphoma of the pleural cavity, inoperable because of local invasion into thoracic wall, who has survived more than 6 years without recurrence. This patient represents the longest reported survival after radiation therapy alone. Radiotherapy holds an important role in the treatment of locally advanced lymphoma of the pleural cavity. 相似文献
83.
H Michibata M Mukoyama I Tanaka S Suga M Nakagawa R Ishibashi M Goto K Akaji Y Fujiwara Y Kiso K Nakao 《Canadian Metallurgical Quarterly》1998,53(4):979-985
Neuropsychological profiles were assessed in a large group of nondemented control subjects (n = 261) and individuals with dementia of the Alzheimer type (DAT) (n = 407) by subjecting their psychometric test results to a factor analysis. Nondemented control subjects were functionally homogeneous with only one factor accounting for the results. The results of the factor analysis on the very mild DAT and mild DAT groups, however, yielded a mental control/frontal factor, a memory-verbal/temporal factor, and a visuospatial/parietal factor. Forty-one of the original set of participants came to autopsy an average of 5.1 years after psychometric testing and had neurofibrillary tangles, total senile plaques, and cored senile plaques estimated from frontal, temporal, and parietal regions. The results of correlations indicated that the relative burden of cored senile plaques was systematically related to the three psychometric factors. These results suggest a connection between the specific functions as defined by neuropsychological measures and specific neuropathology occurring in associated areas of cortex. 相似文献
84.
The permeability of an asymmetrically oxidized poly(L-methionine) film to oxygen dissolved in water was examined. It was recognized that the permeability along an increasing gradient of oxidized methionine composition is higher than the gradient is reversed. A qualitative analysis of this result was presented in terms of the oxygen solubilities into the film and water absorbed in the film. 相似文献
85.
Perpendicular anisotropy of evaporated magnetic films 总被引:1,自引:0,他引:1
Evidence of the existence of origins of perpendicular anisotropy other than the ordinary magnetostrictive effect is presented with a brief review of other studies. As one of these origins, the effect of the grain boundaries or the microscopic shape effect is discussed. The amount of perpendicular anisotropy observed in the stripped films does not seem capable of explanation by this effect only. 相似文献
86.
87.
Matsunaga S Ohshio K Harada E Fujiwara S Uchiyama S Fukui K 《Journal of Bioscience and Bioengineering》2004,98(5):384-386
We applied fluorescent microscopy to monitor the damage of DNA upon exposure to gamma radiation. Our developed dosimetry demonstrated that the number of breaks in DNA is proportional to the dose of the irradiation but is not dependent on dose rate of the irradiation and the GC content of DNA. 相似文献
88.
The origin of the occurrence of nuclei was quantitatively investigated using a microbalance and an electron microscope. The completion time of preferred nucleation and the time variation of the number density of stable nuclei were expressed in terms of measurable quantities such as the sticking coefficient of the incident vapour beam and the surface diffusion distance of adatoms. An analysis of the experimental results showed that the sum of the calculated values of the completion time of preferred nucleation and the appearance time of nuclei ranged from 2 to 60 s, whereas the time at which nucleus saturation occurred was found to range from 100 to 6000 s. It was concluded that the observed increase in the density of nuclei is caused by random nucleation. The occurrence of nucleus saturation can also be explained on the basis of random nucleation and growth coalescence. 相似文献
89.
T. Idehara I. Ogawa La Agusu T. Kanemaki S. Mitsudo T. Saito T. Fujiwara H. Takahashi 《Journal of Infrared, Millimeter and Terahertz Waves》2007,28(6):433-442
Gyrotron FU CW II with an 8 T liquid He free superconducting magnet, the second gyrotron of the THz Gyrotron FU CW Series, has been constructed and the operation test was successfully carried out. It will be used for enhancing the sensitivity of 600 MHz proton-NMR by use of Dynamic Nuclear Polarization (DNP). The designed operation mode of the gyrotron is TE2,6 at the second harmonic. The corresponding frequency is 394.6 GHz. The real operation frequency is 394.3 GHz at TE06 mode, because of fabrication error of the diameter of the cavity. The operation is in complete CW at the output power of around 30 W or higher at the TE06 cavity mode. There are many other operation modes at the fundamental and the second harmonic. Typical output power of the fundamental and the second harmonic are higher than 100 W and 20 W, respectively. The highest frequency observed up to the present is 443.5 GHz at the second harmonic operation of TE6,5 mode. The measured results are compared with the theoretical consideration. 相似文献
90.
Takaki K. Kanesawa K. Mukaigawa S. Fujiwara T. Go T. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2007,14(4):834-845
Characteristics of a pulse corona reactor driven by an inductive energy storage (IES) pulsed power generator are described in this paper with focusing on the influence of streamer-to-glow transition on NO removal efficiency. A pulsed high voltage with a short rise time of under 30 ns is employed to generate streamer discharges homogeneously in whole the discharge region. Fast recovery diodes are used as semiconductor opening switch (SOS) to shorten the rise time. The various resistors are employed as dummy load to clarify a suitable circuit parameter such as the capacitance of a primary energy storage capacitor and/or the inductance of a secondary energy storage inductor. The energy transfer efficiency of the pulsed power generator has a maximum value of 50% at 714 Omega dummy load resistance. A co-axial cylinder type discharge chamber was used as the corona discharge plasma reactor driven by the IES pulsed power generator. The pulsed power generator supplies 30 kV pulse with 300 pps repetition rate. The co-axial cylinder plasma reactor consists of 1 mm diameter tungsten wire and 19 mm i.d. copper tube with 30 cm length. NO removal from the simulated diesel engine exhaust gas (N2:O2=9:1, Initial NO concentration=200 ppm) increased with input energy into the reactor. The energy efficiency for NO removal was obtained to be 25 g/kWh at 30 % removal in gas flow rate of 2 L/min. However, the energy efficiency decreased to 5 g/kWh with increasing capacitance of the primary capacitor from several hundreds pF to several nF. This decrease was caused by a streamer-to-glow transition. The efficiency was affected by oxygen concentration in the gas mixture. 相似文献