全文获取类型
收费全文 | 579篇 |
免费 | 28篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 608篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 16篇 |
2020年 | 8篇 |
2019年 | 18篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 18篇 |
2015年 | 8篇 |
2014年 | 27篇 |
2013年 | 40篇 |
2012年 | 45篇 |
2011年 | 49篇 |
2010年 | 33篇 |
2009年 | 38篇 |
2008年 | 39篇 |
2007年 | 41篇 |
2006年 | 24篇 |
2005年 | 26篇 |
2004年 | 16篇 |
2003年 | 14篇 |
2002年 | 16篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 12篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有608条查询结果,搜索用时 359 毫秒
81.
Koyama D Isago R Nakamura K 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(3):596-602
A liquid lens is proposed that uses acoustic radiation force with no mechanical moving parts. It consists of a cylindrical acrylic cell filled with two immiscible liquids (degassed water and silicone oil) and a concave ultrasound transducer. The focal point of the transducer is located on the oil-water interface, which functions as a lens. The acoustic radiation force is generated when there is a difference in the acoustic energy densities of different media. An acoustic standing wave was generated in the axial direction of the lens and the variation of the shape of the oil-water interface was observed by optical coherence tomography (OCT). The lens profile can be rapidly changed by varying the acoustic radiation force from the transducer. The kinematic viscosity of silicone oil was optimized to minimize the response times of the lens. Response times of 40 and 80 ms when switching ultrasonic radiation on and off were obtained with a kinematic viscosity of 200 cSt. The path of a laser beam transmitted through the lens was calculated by ray-tracing simulations based on the experimental results obtained by OCT. The transmitted laser beam could be focused by applying an input voltage. The liquid lens could be operated as a variable-focus lens by varying the input voltage. 相似文献
82.
Hibi Y Asai K Arafuka H Hamajima M Iwama T Kawai K 《Journal of Bioscience and Bioengineering》2011,111(5):547-549
La(3+) and not Ca(2+) increases methanol dehydrogenase (MDH) activity in Methylobacterium radiotolerans NBRC15690. La(3+)- and Ca(2+)-MDH-like proteins were found to be homodimeric (α(2)) and heterotetrameric (α(2)β(2)), respectively. N-terminal amino acid sequences of these proteins revealed that La(3+)- and Ca(2+)-MDH-like proteins were encoded by xoxF and mxaFI, respectively. 相似文献
83.
84.
K Iida K Fujita H Hirai H Goto S Miyazaki Y Arai H Iwaki M Otake S Sassa M Maemura T Nakayama H Kudo S Sakamoto 《Canadian Metallurgical Quarterly》1997,21(5):476-482
Polysaccharides extracted from human tubercle bacilli (specific substance of Maruyama [SSM]) have been clinically applied with satisfactory results. Thymidylate synthetase (TS) and thymidine kinase (TK) are key enzymes in de novo and salvage pathways for pyrimidine nucleotide synthesis. Well- and moderately well differentiated adenocarcinomas induced with 1,2-dimethylhydrazine (DMH) are widely distributed throughout the colorectal tract with high TK activity, and the poorly differentiated type is mainly restricted in the proximal colon and the cecum with high TS activity in rats. Subcutaneously injecting the rats with SSM reduced TS activity in colonic nontumorous regions, but in the tumorous regions it reduced TK activity compared with that of the DMH-treated rats without SSM treatment. SSM is suggested to reduce the colorectal carcinogenesis induced with DMH by inhibiting DNA synthesis in a de novo pathway, and to suppress the development of the tumors by decreasing DNA synthesis in the salvage pathway in rats. 相似文献
85.
Kentaro Kuratani Masayasu Uemura Minoru Mizuhata Akihiko Kajinami Shigehito Deki 《Journal of the American Ceramic Society》2005,88(10):2923-2927
We report on the direct deposition of high-quality ZrO2 thin films on various kinds of substrates by the liquid phase deposition method. After reaction for 24 h, thin films formed on various kinds of substrates, and the obtained thin film was comprised of densely packed nano-sized particles. The film annealed at 500°C showed a tetragonal phase at room temperature and this phenomenon has been discussed from the viewpoint of crystallite size effect. The result of optical transmittance measurement revealed that high transparency, more than 70% transmittance, has been achieved for the film after annealing at 900°C. 相似文献
86.
The time variations in the electrode potential and mass of an electrodeposited CdTe layer when immersed in a deposition bath under an open-circuit condition were examined using an electrochemical QCM in order to observe the oxidation behavior due to dissolved oxygen. The morphology, composition, and crystallinity of the CdTe layer were also examined by SEM, EPMA, and XRD measurements. In the early stage of immersion, mostly only Cd atoms in the CdTe were found to dissolve from the zinc blende-type CdTe lattice, keeping the flat and smooth surface morphology intact. Then, the remaining Te formed a lattice of elemental Te and covered the CdTe layer. The electrolyte could penetrate the Te layer and access the CdTe layer's surface because the Te layer was porous due to the elution of Cd atoms. Therefore, the preferential dissolution of Cd species continued to occur, and finally, only the porous Te layer remained on the substrate. This dissolution of CdTe supports the validity of the potential-pH diagram of the Cd-Te-NH3-H2O system. 相似文献
87.
Kentaro Okada Masataka Mori Kazuko Shimazaki Tatsuji Chuman 《Journal of chemical ecology》1990,16(9):2605-2614
Bioassays were performed on malePeriplaneta americana L. using synthetic (–)-periplanone-B (P-B) and Hauptmann's (–)-periplanone-A (P-A), and their mixtures at various ratios to estimate the roles of both periplanones for the sexual communication of the species. Both P-A and P-B elicited qualitatively the same responses, such as antennal movement, rapid locomotion, wing raising, and homosexual behavior of male cockroaches, but the threshold of the pheromone activities for P-B was two orders of magnitude lower than that of P-A. Neither synergistic nor inhibitory but only a simple integrated effect on the responses was observed when mixtures of P-A and P-B were applied. 相似文献
88.
89.
The nodular type of muscular sarcoidosis has been known to show characteristic MR findings: however, MR imaging features after steroid therapy have not been reported. A 48-year-old man with nodular type of muscular sarcoidosis is reported. Prior to steroid therapy, axial MR images showed peripheral increased signal intensity and central star-shaped decreased signal intensity. Coronal images showed an inner stripe of decreased signal intensity and outer stripes of increased signal intensity. After steroid therapy, axial images showed only the central star-shaped area of decreased signal intensity. Coronal images showed only the inner stripe of decreased signal intensity. It is important to know that the central area will continue to exist after steroid therapy. 相似文献
90.
Kentaro Shinoda Atsushi Yamada Makoto Kambara Yoichi Kojima Toyonobu Yoshida 《Journal of Thermal Spray Technology》2007,16(2):300-305
The deformation of plasma-sprayed alumina droplets of 35-55 μm diameter d with an impact velocity of around 90 m/s has been investigated over various micro-patterned substrates with an arithmetic
mean roughness of 0.5 μm. On a line-and-space pattern, droplets exhibited elliptical splats extending in the direction perpendicular
to the line, when the normalized pattern spacing λ (= x/d) was 0.1-0.3, where x is the pattern spacing. The fingering of the splats was also caused by a concave pattern as well as by a convex pattern and
the number of fingers significantly increased at λ = 0.2. In addition, holes suggesting air entrapment were observed off center
in the bottom side of each splat by approximately 1.5 times the radius of the droplets, regardless of the pattern. These results
suggest the importance of the surface design of substrate on the micrometer scale in plasma spraying. 相似文献