全文获取类型
收费全文 | 419篇 |
免费 | 9篇 |
专业分类
电工技术 | 23篇 |
化学工业 | 67篇 |
金属工艺 | 16篇 |
机械仪表 | 15篇 |
建筑科学 | 13篇 |
能源动力 | 9篇 |
轻工业 | 25篇 |
水利工程 | 3篇 |
无线电 | 56篇 |
一般工业技术 | 85篇 |
冶金工业 | 89篇 |
原子能技术 | 5篇 |
自动化技术 | 22篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 19篇 |
2012年 | 20篇 |
2011年 | 30篇 |
2010年 | 18篇 |
2009年 | 14篇 |
2008年 | 18篇 |
2007年 | 19篇 |
2006年 | 18篇 |
2005年 | 18篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 19篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 28篇 |
1997年 | 24篇 |
1996年 | 13篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1971年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有428条查询结果,搜索用时 15 毫秒
31.
Abstract A new type of resin wool filter (RWF) that persists the load with oil droplets was developed by Kimura and colleagues. In the present work, the initial collection performances of RWF (A and C) are measured for various particle sizes (0.03, 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3 μm) with different charging states at various filtration velocities (0.05, 0.1, 0.15, and 0.3 m/s). As a result, it is shown that the present RWF impregnated with PTBP resin can attain high collection efficiency (99.999% at filtration velocity of 0.05 m/s) with a pressure drop of less than 30 Pa. The charge density is estimated by applying prediction equations of single-fiber collection efficiencies of electret filters with a dipolar charge distribution because no other prediction equation for RWF are available at present. The experimental single-fiber efficiencies for uncharged particles are successfully predicted by assigning a single value of charge density in the prediction equations for dipolar fibers. The estimated charge density on RWF fibers is 2.1 × 10? 4 C/m2, which is much higher than those of conventional electret filter media. Therefore, RWF studied in the present work is suitable for the application to respirators as well as room air cleaners. 相似文献
32.
Shingo Date Hiroshi Ishikawa Tomomi Otani Yukio Takahashi Takanori Nakazawa 《Nuclear Engineering and Design》2008,238(2):353-367
Low-carbon 316 stainless steel with medium-nitrogen (316FR) is considered as the principal structural material for next generation fast breeder reactor (FBR) plants in Japan. The material strength standard and the creep-fatigue life evaluation method for 316FR have been developed. However, they are based on the results of material tests in air, while actual structural material will be used mainly in liquid sodium environment in the plants. In order to clarify the environmental effect, cyclic bending tests were carried out with and without hold time in sodium. Tested materials were 316FR and conventional 304 and 316 stainless steels. Weld metal of 316FR was also tested. As a result, it was found that fatigue and creep-fatigue lives of 316FR in sodium were larger than those in air and no explicit consideration of the environmental effect is necessary in design. It was also found that the life evaluation method based on the ductility exhaustion concept is applicable to creep-fatigue life assessment in sodium. 相似文献
33.
Experimental results are presented for the strength and lifetime in creep rupture of carbon-epoxy microcomposites consisting of seven carbon fibres (Hercules IM6) within an epoxy matrix (Dow DER 332 epoxy with Texaco Jeffamine T403 curing agent) in an approximately hexagonal configuration. Special attention was paid to clamping, specimen alignment, shock isolation and accurate lifetime measurement. The results were analysed using a previously developed model, which involves a Weibull distribution for fibre strength and micromechanical stress redistribution around fibre breaks where the matrix creeps in shear following a power law. The model yields Weibull distributions for both microcomposite strength and lifetime where the respective shape and scale parameters depend on model parameters such as the Weibull shape parameter for fibre strength, the exponent for matrix creep, and the effective load transfer length and critical cluster size for failed fibres. Experimental results were consistent with the theory, though a fractographic study suggested time-dependent debonding along the fibre-matrix interface as being a key mechanism. Arguments were given to suggest, however, that the overall analytical forms would essentially be preserved. The results were compared with earlier results using a different epoxy system (Dow DER 331 epoxy with DEH 26 curing agent). Values for the matrix creep exponent and the effective load transfer length were about double and triple respectively the values from the earlier study, leading to slightly reduced strength, about one-half the variability in lifetime, but almost one-half the value of the exponent for the power law relating microcomposite lifetime to stress level. 相似文献
34.
Kazuto Noda Akihisa Koga Norio Kawakami Thomas Pruschke 《Journal of Low Temperature Physics》2010,158(1-2):79-84
We study two-component ultracold fermions with repulsive interactions, which are loaded into a decorated square lattice. By combining the real-space dynamical mean-field theory with the numerical renormalization group method, we discuss magnetic properties in the system. It is clarified how the ferromagnetically ordered ground state, which is stabilized by a flat band mechanism, is adiabatically connected to the ferrimagnetically ordered state expected in the strong coupling limit. 相似文献
35.
In recent years, X-ray CT scanners with task-specific modifications, such as microfocus and/or a synchrotron, have been widely implemented in a variety of fields, including medical and industrial fields. Since microfocus X-ray CT systems enable the visualization of whole samples, and also yield a relatively high resolution of the region of interest in the sample, they are commonly utilized in the fields of soil mechanics and geotechnical engineering. This paper describes a novel loading test apparatus that is specifically designed for microfocus X-ray CT systems capable of performing loading tests to investigate soil behavior during the installation of driven open-section piles. The loading tests were designed to take the micro-level spatial resolution of microfocus X-ray CT systems into account. Digital image correlation (DIC) is subsequently implemented to analyze the obtained CT images, making it possible for measurements to be taken of the displacement fields in the ground following installation of the model pile. Finally, the versatility of this novel test apparatus is proof of its high potential for application in different types of loading tests. 相似文献
36.
M Ohgami Y Otani K Kumai T Kubota YI Kim M Kitajima 《Canadian Metallurgical Quarterly》1999,23(2):187-92; discussion 192-3
Sixty-one patients who were diagnosed with mucosal gastric cancer have been successfully treated with two laparoscopic techniques at our institute from March 1992 to March 1997. One is laparoscopic wedge resection of the stomach using a lesion-lifting method for lesions of the anterior wall, the lesser curvature, and the greater curvature of the stomach. The other is laparoscopic intragastric mucosal resection for lesions of the posterior wall of the stomach and near the cardia or the pylorus. Indications are as follows: (1) preoperatively diagnosed mucosal cancer; (2) <25 mm diameter elevated lesions; and (3) <15 mm diameter depressed lesions without ulcer formation. Patients were discharged in 4 to 8 days uneventfully. There was no major complication or mortality. The resected specimens had sufficient surgical margins horizontally (16 +/- 5 and 8 +/- 4 mm, respectively) and vertically. In one patient histologic examination revealed slight tumor infiltration into the submucosal layer with lymphatic invasion. He underwent gastrectomy with lymph node dissection 1 month after surgery. Otherwise, histologic examination revealed curative surgery. All patients in the series have survived during the 4- to 65-month follow-up period. There have been two recurrences in the series, both of which were found near the staple line 2 years after the initial surgery and were still mucosal lesions. They were successfully treated by open gastrectomy and laser irradiation. A separate early gastric cancer was found 2 years after the initial surgery in one patient, who then underwent curative open gastrectomy. In conclusion, if the patients are selected properly, these laparoscopic procedures are curative, minimally invasive treatment for early gastric cancer. 相似文献
37.
38.
Disseminated intra-abdominal cystic lymphangiomatosis with severe intestinal bleeding. A case report
A Iwabuchi M Otaka A Okuyama M Jin S Otani S Itoh H Sasahara M Odashima H Kotanagi M Satoh H Masuda O Masamune 《Canadian Metallurgical Quarterly》1997,25(1):383-386
We describe cystic lymphangiomatosis with intestinal bleeding developing multiple lymphangiomas in the small intestine, mesentery, mesocolon, omentum, retroperitoneum, and spleen. Small intestinal fluorography showed multiple polypoid lesions, mainly in the jejunum. Ultrasonography, computed tomography, and magnetic resonance imaging showed diffuse cystic tumors in the mesentery and spleen. Cystic lymphangiomatosis was proved by histologic findings of the biopsied specimen at laparotomy. 相似文献
39.
K Uemura H Otani K Sakamoto Y Sakanishi T Ota T Kobayashi N Ariyoshi A Shirahata 《Canadian Metallurgical Quarterly》1995,43(11):1173-1177
To our knowledge, this report represents the first confirmed case in Japan of a 15-year-old boy with acute lymphoblastic leukemia (ALL).L3 with hand-mirror cells (HMC) in the bone marrow. HMC lymphoid leukemia is an unusual variant of ALL in which the bone marrow lymphoblasts manifest distinctive hand-mirror morphologic features. HMC lymphoblast is characterized by an asymmetric foot-like cytoplasmic process that extends from the portion of the cell, thus giving it the light-microscopic appearance responsible for its name. Besides ALL, HMC has been reported in acute myeloblastic leukemia (AML), blastic crisis of chronic myelogenous leukemia, non-Hodgkin's lymphoma, and infectious mononucleosis. HMC has been reported to be prevalent in ALL.L1 and L2 as compared with L3. 相似文献
40.
T Kawauchi T Sasaki K Yoshida H Matsumoto RX Chen MY Huang KS Tsuchiya T Otani 《Canadian Metallurgical Quarterly》1997,50(4):297-303
beta-(2-Hydroxyethoxy)-5 alpha-cholest-8(14)-en-15-one, a synthetic inhibitor of cholesterol biosynthesis, was shown to exhibit a high affinity to oxysterol binding protein. This was proved by ultracentrifugation of the protein fraction from rabbit liver in the presence of the 3H-labeled inhibitor, 3 beta-(2-hydroxy-2-[3H]ethoxy)-5 alpha-cholest-8(14)-en-15-one, or by the substitution of the [3H]-25-hydroxycholesterol in its complex with the oxysterol binding protein. In human hepatoma Hep G2 cells, the inhibitor decreased activity of 3-hydroxy-3-methylglutaryl CoA reductase [ID50 (2.7 +/- 0.7) x 10(-5) M] and was transformed into 3 beta-[2-(9-Z-octadecenoyloxy)ethoxy]-5 alpha-cholest-8(14)-en-15-one. 相似文献