全文获取类型
收费全文 | 644篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 32篇 |
化学工业 | 65篇 |
金属工艺 | 15篇 |
机械仪表 | 10篇 |
建筑科学 | 11篇 |
能源动力 | 19篇 |
轻工业 | 37篇 |
水利工程 | 2篇 |
无线电 | 102篇 |
一般工业技术 | 109篇 |
冶金工业 | 171篇 |
原子能技术 | 37篇 |
自动化技术 | 54篇 |
出版年
2023年 | 3篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 4篇 |
2015年 | 13篇 |
2014年 | 9篇 |
2013年 | 18篇 |
2012年 | 17篇 |
2011年 | 24篇 |
2010年 | 21篇 |
2009年 | 46篇 |
2008年 | 26篇 |
2007年 | 14篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 15篇 |
1998年 | 74篇 |
1997年 | 51篇 |
1996年 | 23篇 |
1995年 | 29篇 |
1994年 | 27篇 |
1993年 | 26篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 2篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有664条查询结果,搜索用时 17 毫秒
91.
Nobuhiro Seki Shoichiro Fukusako Hideo Inaba 《International Journal of Heat and Mass Transfer》1978,21(7):985-989
This paper presents an experimental investigation of convective heat transfer in a confined rectangular cavity packed with porous media, on the opposing vertical walls of which different temperatures are imposed. Measurements are made for each of two kinds of solid particles using three kinds of fluids, i.e. water, transformer oil and ethyl alcohol. The present experiments cover a wide range of Rayleigh number Ra1 between 1 and 105, Prandtl number Pr1 between 1 and 200 and geometrical aspect-ratio between 5 and 26. The experimental results indicate that Nusselt number Nu1 is correlated by the following relationship: 相似文献
92.
93.
K Yoshida K Yoshitomo-Nakagawa N Seki M Sasaki S Sugano 《Canadian Metallurgical Quarterly》1998,49(3):458-461
A method is described that allows simultaneous measurement of two spectrally distinguishable green fluorescent protein (GFP) mutants with a confocal microscope. In contrast to previously described methods, neither UV excitation nor repetition of scans is required. Therefore the method is well-suited to the long-time observation of living cells in three-dimensional microscopy and time series recording, as demonstrated with GFP-expressing Dictyostelium discoideum cells. 相似文献
94.
E Noguchi N Hayashi Y Azuma T Seki M Nakamura N Nakashima M Yanagida X He U Mueller S Sazer T Nishimoto 《Canadian Metallurgical Quarterly》1996,15(20):5595-5605
Using the two-hybrid method, we isolated a Saccharomyces cerevisiae cDNA encoding a protein homologous to Schizosaccharomyces pombe protein Dis3sp, using as bait, human GTPase Ran. The DIS3 gene is essential for viability and complements S.pombe mutant dis3-54 which is defective in mitosis. Although Dis3sc has no homology to RanBP1, it bound directly to Ran and the S.cerevisiae Ran homologue Cnr1, but not to the S.cerevisiae RCC1 homologue Srm1. Upon binding to Ran with a 1:1 molar ratio, Dis3sc enhanced a nucleotide-releasing activity of RCC1 on Ran. In the presence of Dis3sc, the K(m) of RCC1 on Ran decreased by half, while the kcat was unchanged. In vivo, Dis3sp was present as oligomers of M(r) 670-200 kDa as previously reported, and the 200 kDa oligomer of Dis3sp was found to include Spi1 and Pim1, the S.pombe homologues of Ran and RCC1, respectively. Although the biological function of the heterotrimeric oligomer consisting of Dis3, Spi1 and Pim1 is unknown, our results indicate that Dis3 is a component of the RCC1-Ran pathway. 相似文献
95.
Kitamura M. Seki M. Yamaguchi M. Mito I. Kobayashi Ke. Kobayashi Ko. Matsuoka T. 《Electronics letters》1983,19(20):840-841
CW light output power as high as 38 mW at room temperature and with a CW operable temperature as high as 80°C, both under single-longitudinal-mode operation, has been achieved for the first time in newly developed 1.3 ?m distributed-feedback (DFB) laser diodes with a double-channel planar buried heterostructure (DC-PBH). 相似文献
96.
This paper presents a method for describing and reasoning about the behavior of VLSI circuits within the framework of Extended Temporal Logic. For a reasoning method, an “ω-graph approach” is proposed which is useful in verifying the validity of a design. Not only verification but also other reasoning about circuit properties, such as unknown signal identification, can be treated in a unified way by this ω-graph approach. This approach has been studied as a basis of an expert system for the authors’ VLSI CAD system. 相似文献
97.
The electroencephalograms of 82 infants (between 27 and 37 weeks of conceptional age) recorded during the neonatal period were analyzed and compared with the ultimate clinical evolution. Three groups of infants were identified according to their neurological state at 3 years of age or older: group A: normal (34 infants), group B: minor neurological sequellae (13 infants) and group C: major neurological sequellae (17 infants). A fourth group (group D: 18 infants) died during the neonatal period. The E.E.Gs were classified as: normal, questionably abnormal, moderately abnormal or grossly abnormal. The analysis revealed that E.E.Gs classified as grossly abnormal, were found only in groups B, C and D. Serial E.E.Gs were of more value in distinguishing these groups. Only infants in groups C and D (with I exceptional case in group B) had E.E.Gs which remained abnormal for several weeks or which deteriorated during the neonatal period. This study shows the prognostic value of the E.E.G. recorded during the neonatal period, particularly serial recordings obtained during and after a period of clinical deterioration. A detailed statistical analysis of the E.E.Gs is in progress. 相似文献
98.
Shozo Ishizaka John G. Stockner Katsumi Kobayashi Kunihiro Shima Kenji Katori Humitake Seki 《Water research》1983,17(12):1815-1821
Multi-elemental traces comprising particulate matter in natural water collected during summer in 1978 and 1979 from British Columbia, Canada, were analyzed by α-particle excited X-ray fluorometry. Common elements from all waters examined were Si, Cl, Ca and Fe. The similarity of their distribution in different aquatic environments was statistically analyzed. They were distributed homogeneously in the marine environment but heterogeneously in the freshwater environments. No heavy metals concerned with the environmental standards were detected for all waters examined. 相似文献
99.
Alumina gels that form porous transparent Al2O3 总被引:1,自引:0,他引:1
Bulent E. Yoldas 《Journal of Materials Science》1975,10(11):1856-1860
Formation of a porous transparent Al2O3 from aluminium alkoxides has been previously reported. During the process, alkoxides are hydrolyzed and the resultant hydroxide is peptized to a clear sol. The sol then must be gelled and pyrolyzed to 500° C to obtain the aluminium oxide. This paper discusses the gel state and the requirements for the system to retain its integrity during the drying and pyrolysis. Influence of electrolytes on the sol-gel transformation shows that there is a critical electrolyte concentration at which the gelling volume goes through a pronounced minimum. Deviation in either direction of this electrolyte concentration causes a sharp increase in the relative gelling volume and detrimentally effects the capability of the gel to retain its integrity. The sols that gel at concentrations less than ~4 g equivalent oxide per 100 ml do not retain their integrity during pyrolysis. 相似文献
100.