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排序方式: 共有333条查询结果,搜索用时 15 毫秒
61.
Study of meniscus behavior and surface properties during casting in a high-frequency magnetic field 总被引:6,自引:0,他引:6
Tingju Li Shinji Nagaya Kensuke Sassa Shigeo Asai 《Metallurgical and Materials Transactions B》1995,26(2):353-359
Surface quality of continuously cast metals can be improved by imposing a continuous high-frequency magnetic field from the
outside of a mold. Newly proposed concepts of “soft contacting solidification” and “slow cooling solidification,” which is
tightly related to the mechanism of improving surface quality, were confirmed in model experiments by using molten gallium
and tin. The meniscus motion of the molten gallium accompanied by a mold oscillation and magnetic pressure was measured by
a laser level sensor. The shape variation of a meniscus and the process of ripple formation in an oscillation cycle were directly
visualized by an optical fiberscope camera. Moreover, molten tin was continuously cast and the relationship between the surface
quality and the meniscus motion was studied. A mechanical model for predicting the space between the oscillation marks is
proposed. The casting process using intermittent highfrequency magnetic field was developed. New functions of this field were
investigated regarding the control of initial solidification. It was found that the surface quality of the continuously cast
metal can be improved by the intermittent high-frequency magnetic field as well as the continuous high-frequency magnetic
field.
Formerly Undergraduate Student, Department of Materials Processing Engineering, Nagoya University, 相似文献
62.
H Inagaki T Kawai M Miyata S Nagaya H Tateyama T Eimoto 《Canadian Metallurgical Quarterly》1996,27(8):761-765
Syphilis is an unexpected diagnosis in the stomach. To establish the diagnosis, evidence of Treponema pallidum in the gastric lesion is necessary. However, it is sometimes difficult to prove the presence of the organisms by conventional methods. The authors describe two cases of early gastric syphilis with pseudolymphomatous histology in which T pallidum gene was detected by the polymerase chain reaction (PCR) using paraffin biopsy sections. The gastric lesion of each case endoscopically and histologically simulated that of malignant lymphoma. However, no clonality was proved by immunohistochemistry or PCR gene rearrangement analysis. No spirochetal organisms were detected with certainty by Warthin-Starry silver stain, whereas the organisms were shown by immunofluorescent stain in one patient. A PCR study showed the treponemal DNA in both patients, and its validity was supported by a direct sequencing and a restriction enzyme digestion. Positive results of serological tests for syphilis and regression of the lesions after antisyphilitic treatment were confirmatory of the diagnosis. Gastric syphilis should be considered as a differential diagnosis when an atypical lymphoid infiltrate fails to show monoclonality. The present PCR method would be helpful in showing T pallidum using routinely processed small biopsy specimens as the tissue source. 相似文献
63.
64.
Jiro Kondo 《Nuclear Engineering and Design》1996,165(3):281-287
Failure of a large system causes disasters. However, after an accident, the causes are frequently attributed to human error when the operators do not survive the accident. It might be difficult to prove that the real cause of the accident is human error. Process decision program chart (PDPC) would be a useful tool in indicating the causes of an accident since it can clearly show that if the operator made the correct choice, the safety of the system could be maintained. The case of the incident of the nuclear reactor at Mihama Unit 2 is indicated by PDPC in which the sequence of events and the operations are indicated in this paper together with the safe operation. One can easily understand the cause of the incident and the way to avoid it. Also, PDPC for the Three Mile Island (TMI) accident is shown. Initially, in order to prevent an accident, mental training and safety culture is most important. The oriental safety culture based on Zentoism, a school of Buddhism is discussed. 相似文献
65.
本文依据前报阐述的数学模拟法的基础方程式和解析方法,系统地讨论了在不同泵供量和纺丝速度的情况下,沿纺丝线的丝条温度和固化点的变化,以及沿纺丝线聚合物的纵向运动速度梯度、纤维的细化过程、纺丝张力和纺丝应力的分布,并对与以上有关的主要参数进行了列表归纳。 相似文献
66.
Takashi Wakasugi Rikuo Ota Jiro Fukunaga 《Journal of the American Ceramic Society》1992,75(11):3129-3132
In order to evaluate the crystallization tendency of glasses, the ratio of the crystallization temperature to the liquidus temperature ( T c / T L ) was obtained by DTA measurement for the Na2 O–B2 O3 and Na2 O–B2 O3 –Al2 O3 systems. The critical cooling rate for glass formation ( Q *) was also measured. The measurements were performed in the composition range of (100 − x )Na2 O–( x )B2 O3 , ( x = 25–35 and 60–100 mol%), and (100 − y )0.5Na2 O·0.5B2 O3 −( y )Al2 O3 , ( y = 6–34 mol%). The relationship between T c / T L and Q * was discussed. A linear relationship between T c / T L and log Q * for these systems was found. Furthermore, the relationship between T c / T L and Q * was verified by computer simulation based on the crystallization kinetics of glass or supercooled liquid. 相似文献
67.
El-Sayed A. Hegazy Isao Ishigaki Ahmed M. Dessouki Abdelgawad Rabie Jiro Okamoto 《应用聚合物科学杂志》1982,27(2):535-543
A kinetic study has been made on the preirradiation grafting of acrylic acid (AAc) onto poly(tetrafluoroethylene–hexafluoropropylene) (FEP) film. The effect of grafting conditions was investigated. The dependencies of the grafting rate on preirradiation dose and monomer concentration were found to be 0.58 and 1.25 order, respectively. The overall activation energy for the graft polymerization was 7.4 kcal/mol. The final degree of grafting increased with preirradiation dose and monomer concentration and slightly decreased as the grafting temperature was elevated. The relationship between the grafting rate and film thickness gave a negative first-order dependency, which is in agreement with that obtained for polytetrafluoroethylene—AAc grafting system. It was reasonably concluded that this grafting proceeds from the surface to the center of film with progressive monomer diffusion through the grafted layer which swells in the monomer solution. 相似文献
68.
Permeation of acid dyes in nylon 6 membrane was measured and analyzed by the dual sorption and diffusion mechanism, comprising partition and Langmuir-type modes. The results were compared with our previous work on diffusion in the same system by the film roll method. Diffusion coefficients of both dye species were found to be similar in magnitude. 相似文献
69.
Toshihiko Maekawa Hiroyuki Nishide Eishun Tsuchida Hideki Ohmichi Jiro Okamoto 《应用聚合物科学杂志》1984,29(12):3795-3801
Acrylic acid was graft-polymerized onto polyethylene powder by preirradiation method. The grafted powder (PE-g-AA) rapidaly adsorbed Sm3? ion in high efficiency. The poly(acrylic acid) grafted to the surface region of PE acted as an effective chelating site for the relatively large Sm ion. The complex formation constant of Sm ion with PE-g-AA was much larger than those of Sm ion with poly(acrylic acid) and propionic acid and of Cu2+ ion with PE-g-AA. 相似文献
70.
Design equations for structural steel members at elevated (fire) temperatures are evaluated through comparisons with nonlinear finite element simulations. The study includes comparative analyses of the American Institute of Steel Construction (AISC) and European Committee for Standardization (CEN) design provisions for laterally unsupported I-shaped columns, beams, and beam-columns at temperatures between ambient to 800 °C. The Eurocode 3 provisions are shown to predict the simulated finite element results within about 10%-20%. On the other hand, the AISC specification predicts strengths that are up to twice as large (unconservative) as the simulated results. The discrepancies are largest for members of intermediate slenderness and temperatures above 300 °C. Modifications to the AISC equations are proposed that provide improved accuracy with calculated strengths typically within 20%-30% of the simulated results. Limitations of the member-based assessments and future research and development needs for structural fire engineering are discussed. 相似文献