全文获取类型
收费全文 | 996篇 |
免费 | 22篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 39篇 |
化学工业 | 177篇 |
金属工艺 | 21篇 |
机械仪表 | 24篇 |
建筑科学 | 15篇 |
能源动力 | 20篇 |
轻工业 | 104篇 |
水利工程 | 1篇 |
无线电 | 98篇 |
一般工业技术 | 185篇 |
冶金工业 | 262篇 |
原子能技术 | 17篇 |
自动化技术 | 58篇 |
出版年
2022年 | 11篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 12篇 |
2016年 | 19篇 |
2015年 | 11篇 |
2014年 | 20篇 |
2013年 | 34篇 |
2012年 | 27篇 |
2011年 | 48篇 |
2010年 | 30篇 |
2009年 | 40篇 |
2008年 | 37篇 |
2007年 | 30篇 |
2006年 | 22篇 |
2005年 | 27篇 |
2004年 | 33篇 |
2003年 | 25篇 |
2002年 | 29篇 |
2001年 | 21篇 |
2000年 | 12篇 |
1999年 | 34篇 |
1998年 | 89篇 |
1997年 | 77篇 |
1996年 | 48篇 |
1995年 | 33篇 |
1994年 | 26篇 |
1993年 | 26篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 2篇 |
1977年 | 9篇 |
1976年 | 15篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 2篇 |
排序方式: 共有1021条查询结果,搜索用时 46 毫秒
991.
Toshiyuki Kawai Mitsuru Takemoto Shunsuke Fujibayashi Haruhiko Akiyama Seiji Yamaguchi Deepak K. Pattanayak Kenji Doi Tomiharu Matsushita Takashi Nakamura Tadashi Kokubo Shuichi Matsuda 《Journal of materials science. Materials in medicine》2013,24(7):1707-1715
Bone ingrowth into porous Ti metal is important for stable fixation of Ti metal implants to surrounding bone. However, without surface treatment this is limited to only a thin region of the outer surface of the Ti metal. In the present study, a porous Ti metal with a porosity of ~60 % and interpore connections of 70–200 micrometers in diameter was investigated in terms of its chemical and heat treatments, by implanting it into rabbit femur for periods varying from 3 to 12 weeks. The porous Ti metal subjected to heat treatment at 600 °C after H2SO4/HCl mixed acid treatment showed the largest bone ingrowth in comparison with those subjected to no treatment, only acid treatment, and only heat treatment even at an early stage after implantation, and remained as such even 12 weeks after implantation. Their bone ingrowths were well interpreted in terms of apatite-forming abilities of the Ti metals in body environment. Their apatite-forming abilities did not depend upon their surface roughness nor type of crystalline phase, but upon the positive surface charge. 相似文献
992.
In the present study, a three-pole probe is proposed for measurement of Barkhausen noise (BN). A system was constructed for forming a magnetic field using the three-pole probe and succeeded in forming rotating magnetic fields of the same amplitude in all directions and arbitrary orientated stationary alternating magnetic fields. Furthermore, a BN measurement system was constructed and used to measure the BN of a grain-oriented electrical steel sheet. The results show that the BN exhibits a large output in the direction of the easy magnetization axis of the specimen, and it is demonstrated that the BN measurement result using the rotating magnetic field formed by the three-pole probe is reliable. 相似文献
993.
B. M. Schfer N. Kawai 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2003,500(1-3):263-271
The High-Energy Transient Explorer, launched in October 2000, is a satellite experiment dedicated to the study of γ-ray bursts in a very wide energy range from soft X-ray to γ-ray wavelengths. The intermediate X-ray range (2–30 keV) is covered by the Wide-field X-ray Monitor (WXM), a coded aperture imager. In this article, an algorithm for reconstructing the positions of γ-ray bursts is described, which is capable of correcting systematic aberrations to approximately 1′ throughout the field of view. Functionality and performance of this algorithm have been validated using data from Monte-Carlo simulations as well as from astrometric observations of the X-ray source Scorpius X-1. 相似文献
994.
Microlens arrays for integral imaging system 总被引:1,自引:0,他引:1
When designing a system capable of capturing and displaying 3D moving images in real time by the integral imaging (II) method, one challenge is to eliminate pseudoscopic images. To overcome this problem, we propose a simple system with an array of three convex lenses. First, the lateral magnification of the elemental optics and the expansion of an elemental image is described by geometrical optics, confirming that the elemental optics satisfies the conditions under which pseudoscopic images can be avoided. In using the II method, adjacent elemental images must not overlap, a condition also satisfied by the proposed optical system. Next, an experiment carried out to acquire and display 3D images is described. The real-time system we have constructed comprises an elemental optics array with 54 H x 59 V elements, a CCD camera to capture a group of elemental images created by the lens array, and a liquid crystal panel to display these images. The results of the experiment confirm that the system produces orthoscopic images in real time, and thus is effective for real-time application of the II method. 相似文献
995.
A gas engine driven hybrid air conditioning system was constructed; it consisted of a gas engine, a single-stage compression-type refrigerator, and a single-effect absorption-type refrigerator that can be driven by shaft power and waste heat, respectively, from the gas engine. Its efficiency is greatly enhanced as compared to a conventional gas engine heat pump because it utilizes waste heat from the gas engine. This study used simulation and experiments to elucidate the static characteristics of this air conditioning system and develop a control system to drive this combined system efficiently. In the simulation results, the system COP at the design point was about 1.87 and, at 50% partial load operation, the performance increased by 14% because of the simultaneous manipulation of the input gas flow rate and hot water flow rate. The validity of the simulation was confirmed by experiments carried out using the actual constructed machine. 相似文献
996.
Masashi Tanaka Mitsuru Takemoto Shunsuke Fujibayashi Toshiyuki Kawai Masako Tsukanaka Kimiaki Takami Satoshi Motojima Hikaru Inoue Takashi Nakamura Shuichi Matsuda 《Journal of materials science. Materials in medicine》2014,25(6):1505-1517
Two novel calcium phosphate cements (CPC) have been developed using calcium sodium phosphate (CSP) as the main ingredient. The first of these cements, labeled CAC, contained CSP, α-tricalcium phosphate (TCP), and anhydrous citric acid, whereas the second, labeled CABC, contained CSP, α-TCP, β-TCP, and anhydrous citric acid. Biopex®-R (PENTAX, Tokyo, Japan), which is a commercially available CPC (Com-CPC), and OSferion® (Olympus Terumo Biomaterials Corp., Tokyo, Japan), which is a commercially available porous β-TCP, were used as reference controls for analysis. In vitro analysis showed that CABC set in 5.7 ± 0.3 min at 22 °C and had a compressive strength of 86.0 ± 9.7 MPa after 5 days. Furthermore, this material had a compressive strength of 26.7 ± 3.7 MPa after 2 h in physiologic saline. CAC showed a statistically significantly lower compressive strength in the presence of physiologic saline and statistically significantly longer setting times than those of CABC. CABC and CAC exhibited apatite-forming abilities in simulated body fluid that were faster than that of Com-CPC. Samples of the materials were implanted into the femoral condyles of rabbits for in vivo analysis, and subsequent histological examinations revealed that CABC exhibited superior osteoconductivity and equivalent bioresorbability compared with Com-CPC, as well as superior osteoconductivity and bioresorbability compared with CAC. CABC could therefore be used as an alternative bone substitute material. 相似文献
997.
Two clear resonance peaks for each bias direction accompanying negative differential resistance are observed in the Al0.3Ga0.7/GaAs/Al0.3Ga0.7As double-barrier diode of 24 to 26 monolayer well thickness. These two peaks are found to be the resonant tunnelling through the ground and first excited energy levels in the well. 相似文献
998.
Adsorption of lysozyme over layered silicate, denoted as RUB-15, and the modified compound RUB-15-nano have been studied. The amount of enzyme adsorbed onto RUB-15 or RUB-15-nano was smaller than that recently reported as being adsorbed onto mesoporous silicas such as MCM-41 or SBA-15. However, lysozyme adsorbed onto RUB-15-nano exhibits enzymatic activity. Lysozyme was found to be immobilized on RUB-15-nano, which was modified from the layered silicate RUB-15. RUB-15-nano may therefore be useful as an inorganic substrate to immobilize enzymes. 相似文献
999.
The ion temperature in a large diameter plasma is measured with the high-resolution optical emission spectroscopy. It is found that the ion temperature is low when the radial distribution of the plasma is flat profile compared with that in the case of peaked profile. The results of numerical calculation carried out by using the hybrid model validate the assumption of Boltzmann distribution in plasma and agree well with the experimental results. Thus, it is concluded that the decrease of the ion temperature is caused by the decrease of the radial electric field. 相似文献
1000.
Kobayashi S Kawai W Wakayama S 《Journal of materials science. Materials in medicine》2006,17(11):1089-1093
Hydroxyapatite (HA) is known to be biocompatible and osteoconductive, and can be synthesized chemically. The objective of
the present study is to clarify the effect of pressure during sintering on the mechanical properties of HA. HA was sintered
using a hot press system at a uniaxial pressure ranging from 7.81 to 62.5 MPa at a maximum temperature of 1200∘C with a heating rate of 10∘C/min. The density of the HA increased with increasing pressure and peaked at the sintering pressure of 31.2 MPa. Four-points
bending tests and fracture toughness measurements with indentation method were conducted to clarify the effect of sintering
pressure. Bending strength decreased at the pressure > 31.2 MPa. This result indicates that residual stress generated during
sintering process became larger with increasing pressure. Fracture toughness were also lower with high density HA. 相似文献