全文获取类型
收费全文 | 1138篇 |
免费 | 18篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 54篇 |
化学工业 | 182篇 |
金属工艺 | 44篇 |
机械仪表 | 12篇 |
建筑科学 | 8篇 |
能源动力 | 41篇 |
轻工业 | 53篇 |
水利工程 | 1篇 |
无线电 | 140篇 |
一般工业技术 | 257篇 |
冶金工业 | 305篇 |
原子能技术 | 21篇 |
自动化技术 | 46篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 12篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 25篇 |
2015年 | 10篇 |
2014年 | 24篇 |
2013年 | 53篇 |
2012年 | 28篇 |
2011年 | 40篇 |
2010年 | 29篇 |
2009年 | 52篇 |
2008年 | 47篇 |
2007年 | 43篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 32篇 |
2003年 | 26篇 |
2002年 | 26篇 |
2001年 | 19篇 |
2000年 | 33篇 |
1999年 | 30篇 |
1998年 | 122篇 |
1997年 | 72篇 |
1996年 | 55篇 |
1995年 | 39篇 |
1994年 | 25篇 |
1993年 | 33篇 |
1992年 | 11篇 |
1991年 | 3篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 7篇 |
1984年 | 19篇 |
1983年 | 11篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 9篇 |
1976年 | 14篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有1164条查询结果,搜索用时 0 毫秒
1.
Polyacrylate gels containing Ag+ and TiO2 nanoparticles are shown to swell under UV light and shrink under visible light in water. In work reported by Tetsu Tatsuma and co‐workers on p. 1249, the TiO2 absorbs UV light and reduces the Ag+, whereas the deposited Ag absorbs visible light and dissolves itself. These redox reactions change the interactions between the polymer chains and eventually the volume of the gel, as shown on the cover. 相似文献
2.
Theoretical analysis based on the calculation of phase diagrams was employed for Fe-Si-Co and Fe-Si-Al ordering systems to
clarify the necessity for the occurrence of phase separation in Fe-base ternary ordering systems. The free energy of Fe-base
ternary ordering alloys where B2 and D03 ordered structures are formed is evaluated statistically using a pairwise interaction approximation up to second nearest
neighbours, taking into account not only the atomic interaction but also the magnetic interaction, based on the Bragg-Williams-Gorsky
model. The calculated phase diagrams are consistent with the experimentally obtained ones. The phase diagram calculation in
this work is useful to predict the equilibrium states of the ternary ordering systems. The phase separation in ordering alloys
is caused by the contribution of excess free energies due to ordering. The influences of ferromagnetism on the two-phase regions
are also demonstrated. 相似文献
3.
Kazuhiko Miyazaki Hirofumi Kasada Masayuki Ohtsuka 《Journal of Infrared, Millimeter and Terahertz Waves》1994,15(10):1669-1674
We succeeded in observing the continuously tunable, pulsed InSb SFR (Spin-Flip Raman) laser emission in the infrared region of 11~16µm (11.4~16.3µm) from only one InSb device, merely by adjusting the pumping wavelength (11 lines from the infrared NH3 laser) and the applied magnetic field (0~80 kGauss). 相似文献
4.
5.
Three IgM class anti-H monoclonal antibodies (1E3, 1E5 and 3H1) were obtained from a BALB/c mouse immunized with human O type saliva. These antibodies were found to agglutinate red cells from O group and A and B subgroups but not from Bombay and para-Bombay individuals whose H antigen was barely detected by anti-H reagents. The agglutination reactions of these antibodies were inhibited by H antigens from human tissues. It was also demonstrated that both 1E3 and 3H1 reacted with H disaccharide (Fuc alpha 1-->2Gal beta), H type 1 (Fuc alpha 1-->2Gal beta 1-->3GlcNAc beta), H type 2 (Fuc alpha 1-->2Gal beta 1-->4GlcNAc beta), H type 3 (Fuc alpha 1-->2Gal beta 1-->3GalNAc alpha) and H type 4 (Fuc alpha 1-->2Gal beta 1-->3GalNAc beta) but not with Lea (Gal beta 1-->3[Fuc alpha 1-->4]GlcNAc beta), Leb (Fuc alpha 1-->2Gal beta 1-->3[Fuc alpha 1-->4]GlcNAc beta), X (Gal beta 1-->4[Fuc alpha-->3]GlcNAc beta) or Y (Fuc alpha 1-->2Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc beta). On the other hand, 1E5 was found to react with H type 1, H type 2, Leb and Y. Because of the unique reactivities against various fucosyl linkages these monoclonal antibodies could be useful not only as anti-H reagents but also as reagents for the structural analysis of fucosylated glycoconjugates. 相似文献
6.
In this study, a new method for calculating the dynamic stress intensity factors of a bimaterial bending specimen with an interface crack is proposed by making use of a line-spring model. A pre-cracked bending specimen is modeled by one-dimensional beam finite elements and a line-spring representing the stiffness or compliance of a cracked part. The proposed method enables the one-dimensional analysis of a two-dimensional crack problem; thus the time variations of the dynamic stress intensity factors of a bimaterial bending specimen with an interface crack can be obtained by making use of a personal computer within a few minutes. The results obtained by the proposed method agree reasonably well with those obtained by the two-dimensional finite element method, although a slight difference in period can be found. The proposed method enables rapid evaluation of dynamic stress intensity factors. So a rapid evaluation system of the dynamic fracture toughness of a bimaterial with an interface crack can be achieved by combining an instrumented impact test apparatus with a computer program based on the proposed method which runs on a personal computer. 相似文献
7.
Y Yonemura H Kimura S Fushida K Tugawa Y Nakai M Kaji L Fonseca A Yamaguchi I Miyazaki 《Canadian Metallurgical Quarterly》1993,71(8):2448-2453
BACKGROUND: Proliferative activities of tumors are thought to be prognostic features of malignant tumors, but their value as measured by proliferating cell nuclear antigen (PCNA) labeling remains unclear in gastric cancer. METHODS: PCNA labeling rates (LR) were quantified in 121 paraffin-embedded biopsy specimens from primary tumors by immunocytochemistry. RESULTS: Immunohistochemical analyses have demonstrated that PCNA presents an intense staining in the nuclei of tumor cells and mucous neck cells of gastric glands. The PCNA LR ranged from 12% to 79% (mean +/- standard deviation), and a significant correlation was found between bromodeoxyuridine labeling indices and PCNA LR: PCNA LR were closely associated with tumor size, serosal invasion, and nodal involvement. The patients with tumors with high PCNA LR (greater than 40%) were dead significantly earlier than were those with tumors with low PCNA LR: When the PCNA LR and all the clinicopathologic parameters were entered into a Cox regression model, PCNA LR emerged as an independent prognostic factor. CONCLUSION: These results indicate that PCNA LR may be a potentially useful prognostic factor for gastric cancer. 相似文献
8.
Shuzo Ueda Ryoichi Kurihara Noriyuki Miyazaki Toshikuni Isozaki 《International Journal of Pressure Vessels and Piping》1985,18(3):161-176
The purpose of pipe rupture studies in JAERI is to perform model tests on pipe whip, restraint behavior, jet impingement and jet thrust force, and to establish a computational method for analyzing these phenomena. This report presents the analytical results of 4-inch pipe whip tests under BWR LOCA conditions.Dynamic response analyses were performed using the general-purpose finite element program ADINA. The test pipe was modelled by straight beam elements and the four restraints were modelled by a single truss element. The analytical results were compared with the experimental results. Impact time and maximum total restraint force showed good agreement with experimental results. On the other hand, pipe strain and pipe deflection could not be predicted so well. The reason for this is that the sliding of the restraint during the pipe whip movement cannot be considered in the analyses. 相似文献
9.
The surface chemical states of the perovskite-type compounds, strontium doped lanthanum cobalt oxides (La1?x Sr x CoO3), have been investigated using X-ray photoelectron spectroscopy (XPS). Catalytic oxidations of both methane and CO have also been investigated using flow methods. The chemical composition of the surface of La1?x Sr x CoO3 was very different from that in the bulk, which was measured by X-ray fluorescence spectroscopy (XRFS). The catalytic activity of La1?x Sr x CoO3 increased with an increase in the quantity of cobalt atoms on the surface. 相似文献
10.