全文获取类型
收费全文 | 886篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 39篇 |
综合类 | 3篇 |
化学工业 | 112篇 |
金属工艺 | 33篇 |
机械仪表 | 7篇 |
建筑科学 | 4篇 |
矿业工程 | 1篇 |
能源动力 | 41篇 |
轻工业 | 26篇 |
水利工程 | 2篇 |
无线电 | 91篇 |
一般工业技术 | 148篇 |
冶金工业 | 329篇 |
原子能技术 | 25篇 |
自动化技术 | 45篇 |
出版年
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 1篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 19篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 40篇 |
2012年 | 15篇 |
2011年 | 30篇 |
2010年 | 20篇 |
2009年 | 20篇 |
2008年 | 28篇 |
2007年 | 16篇 |
2006年 | 19篇 |
2005年 | 31篇 |
2004年 | 22篇 |
2003年 | 21篇 |
2002年 | 23篇 |
2001年 | 20篇 |
2000年 | 19篇 |
1999年 | 28篇 |
1998年 | 125篇 |
1997年 | 72篇 |
1996年 | 40篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 29篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 15篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 12篇 |
1976年 | 18篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有906条查询结果,搜索用时 31 毫秒
81.
Y Tamagawa K Kitamura H Hagiwara T Ishida M Nishizawa T Saito Y Iwamoto 《Canadian Metallurgical Quarterly》1997,106(4):338-342
In preparation for the introduction of Project 2000 throughout Scotland, a need was identified to monitor the quality of the learning environment for student nurses in the practice setting. No mechanism existed to measure quality and standards, and a group was formed to devise, pilot and implement an educational audit tool which could address these requirements, since limited information was available in the literature. Using this tool, the group subsequently examined the learning opportunities available, concentrating on the physical environment, the learning climate/environment, and the students' perceptions of the learning environment within the practice setting, across hospital and community sectors, including residential accommodation and nurseries, in the wide geographical area covered by the health board. This paper describes the process by which the tool was formulated, tested and implemented, the problems encountered, and the improvements in communications between teaching and clinical staff, leading to improved opportunities for the provision of excellence in patient care. 相似文献
82.
Simple chest X rays on film are the most common type of image in medical diagnosis. However, amongst the various types of medical X-ray images, they require the highest level of display quality due to the fact that the body structures they capture on film have varying degrees of permeability to X rays. Conventional high-definition digital display technology has not always been able to match the quality of such film images. This has been a major impediment against progress toward the complete digitization of simple chest X rays. The intent of this paper is to examine that, when applied to medical diagnosis of chest X rays, super-high-definition (SHD) images (digital images with resolution exceeding that of HDTV) are capable of producing a level of quality of diagnostic accuracy on a par with conventional film images. We will start out by seeking out the overall transmission characteristics of a system that uses digital radiography and a film digitizer to digitize images. We will then derive gray-scale transform characteristics based on the luminance linear method for approximating, as closely as possible on a CRT, film images on a light box that have wide dynamic range and high luminance. Finally, we will present the results of image evaluation experiments using high-definition CRT monitors. These results indicate that conventional film images and those on super-high-definition CRT monitors have nearly the same quality. They will also show that the contrast mapping selected by radiologists and theoretical luminance linear characteristics were almost the same except in low-luminance regions. We will also discuss radiologists' comments on CRT monitors after they participated in the evaluation experiment. 相似文献
83.
Stress fields on elastic-creep bi-material interfaces with different geometry of the interface edge are analyzed by finite element method. The results reveal that the stress highly concentrates near the interface edge at the loading instant and it gradually decreases as the creep-dominated zone expands from the small-scale creep to the large-scale creep. The stress singularity due to creep which resembles the HRR stress singularity appears near the interface edge in all cases. The stress intensity near the interface edge time-dependently decreases and becomes constant when the transition reaches the steady state. The magnitude is scarcely influenced by the edge shape of elastic material, though it depends on the edge shape of creep material. The stress intensity during the transition can be approximately predicted by the J-integral at the loading instant. 相似文献
84.
Hideomi Ohtsubo Mitsuru Kitamura 《International journal for numerical methods in engineering》1990,29(2):223-244
A quantitative method of a posteriori error estimation based on finite element solutions is developed. The proposed method can estimate the error of solutions obtained by the finite element method for two-dimensional elastic problems with 4-node elements. Since the error is estimated element by element, the proposed method does not require a large memory or long computing time. Not only rectangular elements but also arbitrarily shaped 4-node elements can be used in this method for estimating the error in the finite element computation with high accuracy. The finite element solutions are improved by adding the estimated errors onto the original solutions. The proposed method can be utilized for any type of linear problem if an isoparametric finite element method is used. 相似文献
85.
Yabu T. Geshiro M. Kitamura T. Nishida K. Sawa S. 《Quantum Electronics, IEEE Journal of》2002,38(1):37-46
We propose a new element containing a two-mode nonlinear waveguide consisting of Kerr-like material for all-optical logic circuits. The proposed element, incorporated into the Mach-Zehnder interferometer, functions like a phase shifter. Although the optical waves propagating in the proposed element are monochromatic and identical in polarization, its function is insensitive to the relative phase difference between the incident beams. Using this element, we can realize various logic functions. In this paper, we demonstrate such logic circuits as inverters, distributors, and AND gates 相似文献
86.
Pornthep Chivavibul Makoto Watanabe Seiji Kuroda Jin Kawakita Masayuki Komatsu Kazuto Sato Junya Kitamura 《Journal of Thermal Spray Technology》2011,20(5):1098-1109
Warm spray (WS) process, which can control the temperature of a combustion gas jet used to propel powder, has been successfully
applied to deposit WC-Co coatings. Detrimental reactions resulting from dissolution of WC into Co binder and decarburization
were suppressed effectively by keeping the WC-Co particles’ temperature below the m.p. of the binder phase. In this study,
three nano-structured WC-12Co powders with different particle strengths were prepared by changing the sintering conditions
of spray-dried powder and were deposited by WS. The deposition efficiency and porosity of the coatings decreased with increasing
the particle strength. The coating deposited from the powder with very low particle strength showed significant phase changes,
while those deposited from the higher particle strengths showed almost no change. Particle Image Velocimetry revealed significant
disintegration of the weakest powder, which explains the changes observed. The hardness and wear properties of the former
coating, therefore, were inferior to the other two. 相似文献
87.
Seigo Ito Takayuki Kitamura Yuji Wada Shozo Yanagida 《Solar Energy Materials & Solar Cells》2003,76(1):3-13
A chemical dispersing technique for preparing a coating paste of TiO2 nanoparticles is disclosed to fabricate mesoporous electrodes for dye-sensitized TiO2 solar cells. The suspension of TiO2 (P-25) powder was stirred in aqueous nitric acid at 80°C, and then evaporated to dryness, giving the nitric acid-adsorbed P-25 powder. The coating paste was obtained by mixing the nitric acid-adsorbed P-25 with PEG (Mw 20,000) as a porosity-controlling agent and cellulosic polymer as a thickener. The mesoporous TiO2 films were fabricated on conducting glasses by repetitive coating and calcined at 500°C (30 min). The TiO2 film obtained by the five times repetitive coating (20 μm thickness) resulted in the 1.4 times higher energy conversion efficiency of the dye-sensitized solar cells than that of the one time coating TiO2 film (Voc=690 mV, Jsc=12.2 mA/cm2, the fill FACTOR=0.71 and η=6.0%). 相似文献
88.
Yabin Yan Takashi Sumigawa Fulin Shang Takayuki Kitamura 《Engineering Fracture Mechanics》2011,78(17):2935-2946
Crack initiation and propagation along the Cu/Si interface in multilayered films (Si/Cu/SiN) with different thicknesses of the Cu layer (20 and 200 nm) are experimentally investigated using a nano-cantilever and millimeter-sized four-point bending specimens. To examine the cohesive zone model (CZM) criterion for interfacial delamination along the Cu/Si interface in nanoscale stress concentration, an exponential type of CZM is utilized to simulate the observed delamination processes using the finite element method. After the CZM parameters for the Cu/Si interface are calibrated by experiment, interface cracking in other experiments is predicted. This indicates that the CZM criterion is universally applicable for describing cracking along the interface regardless of specimen dimensions and film thickness which include the differences in plastic behavior and residual stress. The CZM criterion can also predict interfacial cracking along Cu/Si interfaces with different stress singularities. 相似文献
89.
90.
M Amano S Hyodo S Kitamura K Ikuta Y Suzuki A Urano K Aida 《Canadian Metallurgical Quarterly》1995,99(1):22-27
The temporal relationship between testicular maturation and salmon gonadotropin-releasing hormone (sGnRH) mRNA expression was investigated in underyearling precocious male masu salmon, Oncorhynchus masou. Testicular maturation could be experimentally manipulated by changing the length of the light-dark photoperiod; maturation was accelerated in the short photoperiod group (8L-16D) and delayed in the long photoperiod group (16-8D). sGnRH mRNA and total silver grains in these loci in individual fish, increased with advancing testicular maturation. They were maximal in the short photoperiod group in August and in the long photoperiod group in September, when spermiation occurred. In contrast, marked changes in sGnRH synthetic activity in relation to testicular maturation were not observed in the terminal nerve ganglion or in the olfactory bulbs. sGnRH neurons in the preoptic area and the ventral telencephalon are clearly influenced by photoperiod and are involved in the control of gonadal maturation probably via gonadotropin secretion. 相似文献