全文获取类型
收费全文 | 2012篇 |
免费 | 36篇 |
国内免费 | 8篇 |
学科分类
工业技术 | 2056篇 |
出版年
2022年 | 8篇 |
2021年 | 31篇 |
2020年 | 12篇 |
2019年 | 18篇 |
2018年 | 30篇 |
2017年 | 17篇 |
2016年 | 27篇 |
2015年 | 20篇 |
2014年 | 40篇 |
2013年 | 78篇 |
2012年 | 67篇 |
2011年 | 92篇 |
2010年 | 59篇 |
2009年 | 74篇 |
2008年 | 84篇 |
2007年 | 89篇 |
2006年 | 60篇 |
2005年 | 59篇 |
2004年 | 59篇 |
2003年 | 50篇 |
2002年 | 50篇 |
2001年 | 45篇 |
2000年 | 48篇 |
1999年 | 55篇 |
1998年 | 150篇 |
1997年 | 117篇 |
1996年 | 65篇 |
1995年 | 56篇 |
1994年 | 46篇 |
1993年 | 47篇 |
1992年 | 18篇 |
1991年 | 34篇 |
1990年 | 28篇 |
1989年 | 24篇 |
1988年 | 33篇 |
1987年 | 20篇 |
1986年 | 22篇 |
1985年 | 28篇 |
1984年 | 20篇 |
1983年 | 16篇 |
1982年 | 21篇 |
1981年 | 21篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1978年 | 15篇 |
1977年 | 19篇 |
1976年 | 22篇 |
1975年 | 8篇 |
1973年 | 8篇 |
1972年 | 7篇 |
排序方式: 共有2056条查询结果,搜索用时 312 毫秒
71.
A. Yoshikawa C. Fujiwara H. Sato T. Nishi H. Ohta T. Fukuda Y. Waseda G. Boulon M. Ito Y. Guyot K. Lebbou 《Optical Materials》2004,26(4):385
Ca8(La,Yb)2(PO4)6O2 (Yb:CLPA) single crystals with the apatite-type structure could be grown from the melt using the Czochralski method. Grown crystal was 18 mm in diameter and 110 mm in length. It is transparent with slightly blue color. Neither visible inclusion nor crack was observed. Thermal conductivity of Yb:CLPA was calculated from the values of thermal diffusivity, heat capacity measurement and density. Luminescent characterization was carried out from the results of emission, absorption and Raman spectrum. 相似文献
72.
Kobayashi TC Hidaka H Kotegawa H Fujiwara K Eremets MI 《The Review of scientific instruments》2007,78(2):023909
An indenter-type high-pressure cell has been developed for electric and magnetic measurements in low-temperature and high-magnetic-field environments. The maximum pressure achieved at low temperatures is more than 4.5 GPa, which is higher than that of a conventional piston-cylinder cell. The typical sample space at maximum pressure is 1.6 mm in diameter and approximately 0.7 mm in depth, and magnetic measurements such as ac-susceptibility and nuclear magnetic resonance can be performed using a miniature coil. All the components of the indenter cell are made of nonmagnetic materials that have enough thermal conductivity for low-temperature experiments using a 3He/4He dilution refrigerator. Another indenter-type cell designed for a commercial superconducting quantum interference device magnetometer is also reported. 相似文献
73.
Kazushi Terada Shoji Nakamura Taro Nakao Atsushi Kimura Osamu Iwamoto Hideo Harada 《Journal of Nuclear Science and Technology》2016,53(11):1881-1888
Gamma-ray emission probabilities of 241, 243Am and 239Np have been precisely measured with gamma- and alpha-ray spectroscopic methods. The activities of the samples were determined by measuring alpha particles using a Si semiconductor detector. Gamma rays emitted from the samples were measured with a planar type High-Purity Germanium (HPGe) detector. An efficiency curve of the HPGe detector was derived with uncertainties from 0.7% to 2.5% by combining measured efficiencies and Monte Carlo simulation. The gamma-ray emission probabilities for the major gamma rays of these nuclides were determined with uncertainties less than 1.2%. 相似文献
74.
75.
76.
77.
78.
Modeling of Nonlinear Magnetizing Characteristics of Pole Transformer for Analyzing Islanding Prevention of Photovoltaic System 下载免费PDF全文
Yoshiaki Yoshida Hirokazu Suzuki Koji Fujiwara Yoshiyuki Ishihara 《Electrical Engineering in Japan》2014,188(3):46-55
With increasing penetration of distributed generators such as photovoltaic (PV) systems in distribution systems, it is very important to quickly detect islanding caused by power system faults in order to assure electrical safety. We have developed a nonlinear magnetizing characteristics model of pole transformers for use in analyzing islanding prevention in PV systems. Basic experiments on the islanding detection were performed for verification of the proposed model. Analytical results obtained by the proposed model agreed well with experimental results. 相似文献
79.
80.
Although numerous swarm robotic systems have already been developed, they have exhibited limited adaptability. This was partly because the previous researchers designed the control schemes on the basis of informational interaction, without considering the physical effects of the environment. To tackle this problem, we employ an unconventional approach: we design a control scheme for swarm robots based on their physical interaction in a hydrodynamic field, inspired by biological swarming. Through simulations using a smoothed particle hydrodynamics method, we show that the proposed control scheme allows agents to form an ordered swarm in response to their environment. 相似文献