全文获取类型
收费全文 | 460篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 30篇 |
综合类 | 1篇 |
化学工业 | 131篇 |
金属工艺 | 6篇 |
机械仪表 | 11篇 |
建筑科学 | 7篇 |
能源动力 | 18篇 |
轻工业 | 63篇 |
无线电 | 30篇 |
一般工业技术 | 68篇 |
冶金工业 | 81篇 |
原子能技术 | 8篇 |
自动化技术 | 23篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 43篇 |
2012年 | 17篇 |
2011年 | 25篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 22篇 |
2007年 | 20篇 |
2006年 | 9篇 |
2005年 | 16篇 |
2004年 | 8篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 34篇 |
1997年 | 23篇 |
1996年 | 22篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有477条查询结果,搜索用时 15 毫秒
1.
N Usui S Kamata S Ishikawa T Sawai H Okuyama K Imura A Okada 《Canadian Metallurgical Quarterly》1996,31(2):258-262
Bone marrow examination revealed a lipid-laden histiocytosis in seven patients undergoing long-term total parenteral nutrition necessitated by extensive short-bowel surgical resection. Clinical abnormalities occurred during this treatment which required bone marrow examination. These included hepatosplenomegaly and peripheral blood cytopenia; the median time to the detection of these abnormalities was 64 months. The most striking change within the bone marrow was the presence of many pigment-laden histiocytes which had the typical morphology of sea-blue histiocytes seen in the so-called idiopathic sea-blue histiocyte syndrome. The occurrence of sea-blue histiocytosis in the bone marrow in association with long-term parenteral nutrition for short-bowel syndrome has not, to our knowledge, been reported previously and should now be considered in the differential diagnosis of bone marrow sea-blue histiocytosis. 相似文献
2.
Yoshihiro Iida Toshikatsu Tsuyuki Takao Mashima Takeo Takashima Kunito Okuyama 《亚洲传热研究》2002,31(1):28-41
This paper presents a series of experimental results on a passive augmentation technique of boiling heat transfer by supplying solid particles in liquid. A cylindrical heater 0.88 mm in diameter is placed in saturated water, in which a lot of mobile particles exist, and the nucleate and film boiling heat transfer characteristics are measured. Particle materials used were alumina, glass, and porous alumina, and the diameter ranged from 0.3 mm to 2.5 mm. Particles are fluidized by the occurrence of boiling without any additive power, and the heat transfer is augmented. The maximum augmentation ratio obtained in this experiment reaches about ten times the heat transfer coefficient obtained in liquid alone. The augmentation ratio is mainly affected by the particle material, diameter, and the height of the particle bed set at no boiling condition. The augmentation mechanism is discussed on the basis of the experimental results. © 2001 Scripta Technica, Heat Trans Asian Res, 31(1): 28–41, 2002 相似文献
3.
The rate of evaporation of monodisperse water droplets was first evaluated by solving numerically the modified Maxwell equation, assuming the cellular model for a droplet clouds. The results are discussed in comparison with those for a single isolated droplet, which can be obtained analytically. The critical conditions for the droplet cloud to be stable are then evaluated as a function of droplet number concentration, droplet size and initial conditions of the surrounding air. Secondly, the equilibrated system, where a water droplet cloud is steadily mixed with unsaturated air, was analysed on the basis of enthalpy and material balance of the system to evaluate the total volume change of the droplets. Some of these analyses were verified by experiment, using an ultramicroscopic technique which is useful for droplet size analysis. 相似文献
4.
The heterogeneous phase transition of the organic vapours, cyclohexane and p-xylene, on a cold substrate was observed by cooling the substrate at a slow rate under reduced pressure conditions. Either organic vapour at a vapour pressure lower than 130 Pa formed directly solid crystals but p-xylene vapour at a higher vapour pressure formed liquid condensates with subsequent formation of solid crystals. The dependence of the critical supersaturation ratios on the critical temperatures and the physical properties of the organic vapours has been clarified by the equation derived on the basis of classical nucleation theory. 相似文献
5.
Bu-Sang ChaSeung-Mok Lee Takeshi KanashimaMasanori Okuyama Tsunehisa Tanaka 《Sensors and actuators. A, Physical》2011,171(2):191-198
Capacitive micromachined ultrasonic transducers (CMUTs) with a perforated membrane have been fabricated and characterized in air. Two types of CMUT device have been fabricated having perforation ratio (area ratio of holes = AR) of 10% and 20%, and analyzed about electrical and mechanical characteristics. The perforation ratio (AR) of membrane substantially influences on the electrostatic force and mechanical restoring force of the device since it leads to the area variation of electrode and membrane, it subsequently influences on the sensitivity and frequency response of the CMUT device. The electrostatic force and mechanical restoring force were improved by decreasing the AR and increasing the DC bias voltage. The open-circuit sensitivity of a CMUT having AR 10% membrane, 8.45 μV/Pa, is larger than that of AR 20%, 4.07 μV/Pa at DC 15 V. Furthermore, the resonance behaviors were observed in the range of 60-80 kHz, and the resonance frequency could be changed by varying the applied DC voltage and AR. 相似文献
6.
Miyamoto T. Murakami S. Inoue K. Suzuki Y. Nomura T. Popovici D. Noda M. Okuyama M. 《IEEE sensors journal》2005,5(3):398-402
Ferroelectric Ba(Ti/sub 0.85/Sn/sub 0.15/)O/sub 3/ (BTS/sub 15/) thin film is newly prepared on the Pt/Ti/SiO/sub 2//Si substrate by metal-organic decomposition. The firing condition is determined by thermogravimetric and differential thermal analysis. The BTS/sub 15/ thin film with a flat surface and uniform thickness is obtained by spin coating in N/sub 2/ atmosphere that avoids moisture. The BTS/sub 15/ film has a perovskite phase and a preferential [110] texture. It is also found that the crystalline structure is cubic at 24/spl deg/C with a lattice constant of 4.01 /spl Aring/, and a grain size of about 30 nm was estimated by Scherrer equation and SEM image. From P-E hysteresis loop at 20/spl deg/C, the polarization at E=0 and the electric field at P=0 are found to be 1.07 /spl mu/C/cm/sup 2/ and 24.0 kV/cm, respectively. It is observed that the dielectric constant decreases monotonously from about 830 to 630 with increasing temperature ranging from 20/spl deg/C to 50/spl deg/C. Finally, it is found that the BTS/sub 15/ thin film shows a sufficient ferroelectricity and is an attractive material for functional ferroelectric devices, such as thermal-type infrared sensors. 相似文献
7.
Mami Ogimoto Kumi Suzuki Nahoko Haneishi Yuu Kikuchi Mayu Takanashi Naoko Tomioka 《Food Additives and Contaminants: Part B: Surveillance Communications》2016,9(3):185-190
Aluminium (Al) levels of 90 food samples were investigated. Nineteen samples contained Al levels exceeding the tolerable weekly intake (TWI) for young children [body weight (bw): 16 kg] when consuming two servings/week. These samples were purchased multiple times at specific intervals and were evaluated for Al levels. Al was detected in 27 of the 90 samples at levels ranging from 0.01 (limit of quantitation) to 1.06 mg/g. Of these, the Al intake levels in two samples (cookie and scone mix, 1.3 and 2 mg/kg bw/week, respectively) exceeded the TWI as established by European Food Safety Authority, although the level in the scone mix was equivalent to the provisional TWI (PTWI) as established by Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives. The Al levels markedly decreased in 14 of the 19 samples with initially high Al levels. These results indicated reductions in the Al levels to below the PTWI limits in all but two previously identified food samples. 相似文献
8.
Inside Cover: Onocerin Biosynthesis Requires Two Highly Dedicated Triterpene Cyclases in a Fern Lycopodium clavatum (ChemBioChem 4/2016)
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
9.
Shoji Seki Mami Iwasaki Hiroto Makino Yasuhito Yahara Yoshitaka Miyazaki Katsuhiko Kamei Hayato Futakawa Makiko Nogami Nguyen Tran Canh Tung Tatsuro Hirokawa Mamiko Tsuji Yoshiharu Kawaguchi 《International journal of molecular sciences》2022,23(7)
Intervertebral disc (IVD) diseases are common spinal disorders that cause neck or back pain in the presence or absence of an underlying neurological disorder. IVD diseases develop on the basis of degeneration, and there are no established treatments for degeneration. IVD diseases may therefore represent a candidate for the application of regenerative medicine, potentially employing normal human dermal fibroblasts (NHDFs) induced to differentiate into nucleus pulposus (NP) cells. Here, we used a three-dimensional culture system to demonstrate that ectopic expression of MYC, KLF4, NOTO, SOX5, SOX6, and SOX9 in NHDFs generated NP-like cells, detected using Safranin-O staining. Quantitative PCR, microarray analysis, and fluorescence-activated cell sorting revealed that the induced NP cells exhibited a fully differentiated phenotype. These findings may significantly contribute to the development of effective strategies for treating IVD diseases. 相似文献
10.
Physiology and Pathophysiology of Heparan Sulfate in Animal Models: Its Biosynthesis and Degradation
Heparan sulfate (HS) is a type of glycosaminoglycan that plays a key role in a variety of biological functions in neurology, skeletal development, immunology, and tumor metastasis. Biosynthesis of HS is initiated by a link of xylose to Ser residue of HS proteoglycans, followed by the formation of a linker tetrasaccharide. Then, an extension reaction of HS disaccharide occurs through polymerization of many repetitive units consisting of iduronic acid and N-acetylglucosamine. Subsequently, several modification reactions take place to complete the maturation of HS. The sulfation positions of N-, 2-O-, 6-O-, and 3-O- are all mediated by specific enzymes that may have multiple isozymes. C5-epimerization is facilitated by the epimerase enzyme that converts glucuronic acid to iduronic acid. Once these enzymatic reactions have been completed, the desulfation reaction further modifies HS. Apart from HS biosynthesis, the degradation of HS is largely mediated by the lysosome, an intracellular organelle with acidic pH. Mucopolysaccharidosis is a genetic disorder characterized by an accumulation of glycosaminoglycans in the body associated with neuronal, skeletal, and visceral disorders. Genetically modified animal models have significantly contributed to the understanding of the in vivo role of these enzymes. Their role and potential link to diseases are also discussed. 相似文献