全文获取类型
收费全文 | 2921篇 |
免费 | 64篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 194篇 |
化学工业 | 629篇 |
金属工艺 | 99篇 |
机械仪表 | 71篇 |
建筑科学 | 50篇 |
矿业工程 | 1篇 |
能源动力 | 118篇 |
轻工业 | 195篇 |
水利工程 | 9篇 |
石油天然气 | 2篇 |
无线电 | 295篇 |
一般工业技术 | 599篇 |
冶金工业 | 439篇 |
原子能技术 | 85篇 |
自动化技术 | 212篇 |
出版年
2023年 | 7篇 |
2022年 | 29篇 |
2021年 | 42篇 |
2020年 | 21篇 |
2019年 | 24篇 |
2018年 | 35篇 |
2017年 | 37篇 |
2016年 | 47篇 |
2015年 | 31篇 |
2014年 | 66篇 |
2013年 | 136篇 |
2012年 | 83篇 |
2011年 | 146篇 |
2010年 | 102篇 |
2009年 | 102篇 |
2008年 | 128篇 |
2007年 | 131篇 |
2006年 | 115篇 |
2005年 | 114篇 |
2004年 | 87篇 |
2003年 | 93篇 |
2002年 | 92篇 |
2001年 | 60篇 |
2000年 | 61篇 |
1999年 | 81篇 |
1998年 | 199篇 |
1997年 | 145篇 |
1996年 | 102篇 |
1995年 | 66篇 |
1994年 | 64篇 |
1993年 | 59篇 |
1992年 | 35篇 |
1991年 | 40篇 |
1990年 | 34篇 |
1989年 | 24篇 |
1988年 | 40篇 |
1987年 | 31篇 |
1986年 | 26篇 |
1985年 | 34篇 |
1984年 | 30篇 |
1983年 | 19篇 |
1982年 | 18篇 |
1981年 | 23篇 |
1980年 | 20篇 |
1979年 | 27篇 |
1978年 | 21篇 |
1977年 | 13篇 |
1976年 | 18篇 |
1974年 | 6篇 |
1973年 | 8篇 |
排序方式: 共有2998条查询结果,搜索用时 31 毫秒
1.
Ryo Hashikawa Yasuhiro Fujii Atsushi Kinomura Takeshi Saito Arifumi Okada Takashi Wakasugi Kohei Kadono 《Journal of the American Ceramic Society》2019,102(4):1642-1651
Radiophotoluminescence phenomena have been widely investigated on various types of materials for dosimetry applications. We report that an aluminoborosilicate glass containing 0.005 mol% copper exhibits intense photoluminescence in the visible region induced by X-ray and γ-ray irradiation. The luminescence is assigned to the 3d94s1 → 3d10 transition of Cu+. The proportionality of the intensity of the induced photoluminescence to the irradiation dose was confirmed up to 0.5 kGy using 60Co γ-ray irradiation. Based on the spectroscopic results, a potential mechanism was proposed for the enhancement of the photoluminescence. The exposure to the ionizing radiation generates electron-hole pairs in the glass, and the electrons are subsequently captured by the Cu2+ ions, which are converted to Cu+ and emit the luminescence. For the glass containing 0.01 mol% copper, the pronounced enhancement of the photoluminescence was not observed because the reverse reaction, ie, the capture of the holes by the Cu+ ions, becomes prominent. The photoluminescence induced by the irradiation was stably observed for the glasses kept at room temperature and even for the glasses heat-treated at 150°C. However, the induced photoluminescence could be eliminated by the heat treatment at a temperature at 500°C, and the glass returned to the initial pre-irradiation state. The Cu-doped aluminoborosilicate glass is a potential candidate for use in dosimetry applications. 相似文献
2.
In a plant consisting of parallelized microreactors (MRs), the product quality is lowered because of a lack of flow uniformity among them when blockage occurs. It is not practical to install sensors in every MR from the viewpoint of cost when detecting the blocked MRs. In the previous study, the multiple blockage detection (MBD) method using a small number of sensors was proposed, but its performance became low when the number of sensors decreased. Here, the conventional algorithm for MBD is improved by considering the process behavior on blockage occurrence, and the effectiveness of the improved algorithm is demonstrated through a numerical case study. The effects of flow distributor types and sensor types on the MBD performance are numerically investigated. 相似文献
3.
4.
Nayve R. Fujii M. Fukugawa A. Takeuchi T. Murata M. Yamada Y. Koyanagi M. 《Journal of microelectromechanical systems》2004,13(5):814-821
This paper describes the fabrication and characterization of a thermal ink jet (TIJ) printhead suitable for high speed and high-quality printing. The printhead has been fabricated by dicing the bonded wafer, which consists of a bubble generating heater plate and a Si channel plate. The Si channel plate consists of an ink chamber and an ink inlet formed by KOH etching, and a nozzle formed by inductively couple plasma reactive ion etching (ICP RIE). The nozzle formed by RIE has squeezed structures, which contribute to high-energy efficiency of drop ejector and, therefore, successful ejection of small ink drop. The nozzle also has a dome-like structure called channel pit, which contributes to high jetting frequency and high-energy efficiency. These two wafers are directly bonded using electrostatic bonding of full-cured polyimide to Si. The adhesive-less bonding provided an ideal shaped small nozzle orifice. Use of the same material (Si substrate) in heater plate and channel plate enables the fabrication of high precision long printhead because no displacement and delamination occur, which are caused by the difference in thermal expansion coefficient between the plates. With these technologies, we have fabricated a 1" long printhead with 832 nozzles having 800 dots per inch (dpi) resolution and a 4 pl. ink drop volume. 相似文献
5.
6.
On an earthspace propagation path with the low elevation angle of 10 deg, the phase between co- and crosspolar signals occasionally showed rapid and irregular fluctuations during fine weather. These fluctuations were generally significant during the daytime, and were strongly in phase with the occurrence of the copolar amplitude scintillations. This could be attributed to the combined effects of the crosspolar phase pattern of the receiving antenna and small fluctuations of the angle of arrival of the radiowaves. 相似文献
7.
K. Fujii J. Fujimoto H. Hayashii R. Kajikawa Y. Masatani H. Ozaki A. Sugiyama R. Suzaki S. Suzuki T.Y. Tsukamoto T.F. Tsukamoto S. Uno S. Iwata 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,236(1):55-63
We constructed and tested a prototype gas sampling electromagnetic calorimeter of the Pb-proportional tube sandwich type. The calorimeter uses conductive plastic tubes and cathode pad readout with a tower structure which resulted in reasonable energy and spatial resolutions for electrons in the momentum range 0.5–4.0 GeV/c; /c). This paper describes the test and the performance studied under various conditions. 相似文献
8.
Tatara Takako Fujii Tomiko Kawase Tokuzo Minagawa Motoi 《Journal of the American Oil Chemists' Society》1985,62(6):1053-1058
Journal of the American Oil Chemists' Society - Kinetic parameter of hydrolysis, degree of hydrolysis, pH and temperature characteristics and positional specificity of hydrolysis of seven kinds... 相似文献
9.
H Kuniyasu W Yasui F Shimamoto K Fujii M Nakahara T Asahara K Dohi E Tahara 《Canadian Metallurgical Quarterly》1996,46(12):1005-1010
A rare case of hepatoblastoma in a 61-year-old Japanese housewife is described. This liver tumor mainly consisted of two tissue components: embryonal hepatocytes and primitive mesenchymal tissue. Fetal hepatocytes with alpha-fetoprotein production, gland formation, cartilage and osteoid were also found in a small portion. Molecular analysis by slot blot method revealed increased copy numbers of c-met and K-sam proto-oncogenes and cyclin D1 genes. These findings suggest that alterations of these oncogenes might play a role in the development of adult hepatoblastoma. 相似文献
10.
Shingo Hirano Akio Kawabata Masaru Yoshinaka Ken Hirota Osamu Yamaguchi 《Journal of the American Ceramic Society》1995,78(5):1414-1416
A compound denoted as (Ce0.75 Zr0.25 )O2 (Ce, ZrO8 ) is formed near room temperature from cerium and zirconium nitrates using hydrazine monohydrate. It has a cubic unit cell with a = 0.5342 nm. Characterization of powders heated to various temperatures at 10°C/min demonstrates that the specific surface area does not decrease below 20 mVg until >1000°C. 相似文献