全文获取类型
收费全文 | 334篇 |
免费 | 7篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 31篇 |
综合类 | 2篇 |
化学工业 | 87篇 |
金属工艺 | 10篇 |
机械仪表 | 3篇 |
建筑科学 | 3篇 |
矿业工程 | 1篇 |
能源动力 | 21篇 |
轻工业 | 15篇 |
无线电 | 17篇 |
一般工业技术 | 58篇 |
冶金工业 | 41篇 |
原子能技术 | 18篇 |
自动化技术 | 36篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 9篇 |
2013年 | 26篇 |
2012年 | 17篇 |
2011年 | 19篇 |
2010年 | 20篇 |
2009年 | 17篇 |
2008年 | 17篇 |
2007年 | 25篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 9篇 |
1998年 | 23篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1969年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有343条查询结果,搜索用时 62 毫秒
111.
Low temperature synthesis of AlN by addition of various Li-salts 总被引:1,自引:0,他引:1
Yoshikazu Kameshima Masaki Irie Atsuo Yasumori Kiyoshi Okada 《Journal of the European Ceramic Society》2004,24(15-16):3801-3806
The effect of various Li-salts on the low temperature synthesis of AlN by direct nitridation of Al metal was investigated using four Al powders with average particle sizes of 3, 20, 100 and 150 μm. These were mixed with various Li-salts (LiNO3, LiOH·H2O and Li2CO3) in different concentrations and fired at various temperatures under flowing N2. The as-received Al powders without Li addition showed AlN formation at about 600 °C in the 3 and 20 μm samples but no AlN formation up to 850 °C in the 100 and 150 μm samples. The crystallinity of the AlN products, where formed, was however low. By contrast, all the Al powders with added Li-salts showed AlN formation up to 800 °C, with LiOH·H2O being especially effective. Thus, the AlN formation temperature can be significantly lowered in the coarser powders by the addition of Li-salts but the effect is less in the finer powders which undergo low temperature nitridation below the melting point of Al metal even without Li. The crystallinity of the AlN products was higher in the samples containing Li-salts than without Li-salts. 相似文献
112.
113.
114.
Y Kato K Nakamura K Haraguchi A Ajima H Fujita J Tomiyama H Kudo Y Onozawa K Ohnishi N Umekita 《Canadian Metallurgical Quarterly》1998,39(11):1137-1139
A 31-year-old man presented with a 3-month history of petechial hemorrhages. Physical examination revealed no splenomegaly. The patient's platelet count was 1.0 x 10(9)/l and bone marrow aspiration showed an elevated number of megakaryocytes. A diagnosis of HIV-associated thrombocytopenia was made on the basis of HIV seropositive results. The CD4 cell count was 400 x 10(6)/l. No opportunistic infections indicating AIDS were detected. Initially the patient was treated with predonisolone, but showed only a transient response. He also failed to respond to zidovudine, lamivudine, or indinavir. Following splenectomy, however, his platelet count rose above 80 x 10(9)/l (normal level: 150-350 x 10(9)/l). 相似文献
115.
116.
Takayoshi Kusunoki Takahiro Nozue Kosuke Hayashi Shigeo Hosokawa Akio Tomiyama Michio Murase 《Journal of Nuclear Science and Technology》2016,53(4):486-495
In this study, we measured counter-current flow limitation (CCFL) characteristics in an inverted U-tube (18.4 mm diameter and 1.0 m straight-part length) simulating steam generator (SG) U-tubes under conditions of steam condensation at pressures of 0.1–0.14 MPa. Differential pressure ΔP between the top of the inverted U-tube and the lower tank was measured, and the flow patterns wave estimated by comparing the waveforms of ΔP with those in air–water experiments. As a result, we classified the flow patterns under CCFL conditions into CCFL-P, CCFL-L and CCFL-T. The falling water flow rate under CCFL conditions slightly increased as the pressure increased and the cooling water temperature decreased (subcooling of cooling water increased). In the case of CCFL-L, CCFL characteristics in the inverted U-tube were between those in air–water and saturated steam–water experiments at 0.1 MPa. Furthermore, we derived a Wallis type CCFL correlation and its uncertainty from CCFL data, including previously measured data, i.e., J*1/2G + 0.88JL*1/2 = 0.76 ± 0.05. 相似文献
117.
Sogo Y Ito A Yokoyama D Yamazaki A LeGeros RZ 《Journal of materials science. Materials in medicine》2007,18(6):1001-1007
Fluoride (F−)-substituted B-type carbonate hydroxyapatite (CHAP) powders were prepared for application as bone substitute materials having
the ability to enhance bone formation and to suppress bone resorption due to the therapeutic effect of F−. F− was adsorbed on CHAP in a sodium fluoride solution followed by heating at 700°C in carbon dioxide flow to substitute F− for the hydroxyl ion in the CHAP structure. The F− contents in the F-substituted CHAP powders were 16–22 times greater than that in normal adult human bones. The carbonate
ion contents in the F-substituted CHAP powders corresponded to or were higher than that in normal adult human bones. F-substituted
CHAP powder with CO32− and F− contents of 11.03 and 0.66 wt%, respectively, slowly released F− in a physiological salt solution to a sufficiently high F− level. The F− concentration slowly increased and reached 67.20 ± 4.81 μg l−1, which was 1.5–9.3 times higher than that in the body fluid of normal adult humans, near the therapeutic window of F−, and far lower than the estimated toxic level. Therefore, the F-substituted CHAP can promote bone formation. The present
F-substituted CHAP has the advantage of slow F− release over sodium fluoride and sodium monofluorophosphate which are highly soluble salts and cannot be sintered into a
ceramic body. 相似文献
118.
Electron microscopic analysis of a fusion protein of postsynaptic density-95 and metallothionein in cultured hippocampal neurons 总被引:1,自引:0,他引:1
Fukunaga Y Hirase A Kim H Wada N Nishino Y Miyazawa A 《Journal of electron microscopy》2007,56(4):119-129
The subcellular localization of biomolecules at high resolution has traditionally been investigated by combining transmission electron microscopy (TEM) and chemical staining with heavy metals or immuno-based labeling with gold-conjugated antibodies. Here, we employ genetically encoded tags to examine the localization of proteins in transfected cultured cells by TEM. We purified a fusion protein of postsynaptic density-95 (PSD-95) coupled to three tandem repeats of metallothionein (MT) (PDS-95-3MT) from COS7 cells grown in the presence of Cd2+. PSD-95-3MT was detected as black particles by TEM. To visualize the subcellular localization of PSD-95-3MT, expression constructs encoding this fusion protein were transfected into primary hippocampal neurons cultured in medium containing Cd2+. The subcellular accumulation of PSD-95-3MT and Cd2+ provided excellent contrast in TEM micrographs. To address if genetically encoded tags affect the function of the target proteins, we found that the conjugation of 3MT to PSD-95 did not alter its association with known binding partners. These results demonstrate that 3MT coordinating Cd2+ is a valuable genetically encoded tag to study the localization of proteins by TEM. 相似文献
119.
Michio Murase Akio Tomiyama Dirk Lucas Ikuo Kinoshita Yoichi Utanohara Chihiro Yanagi 《Journal of Nuclear Science and Technology》2013,50(4):398-407
Numerical simulations were done to evaluate countercurrent flow limitation (CCFL) characteristics in a pressurized water reactor (PWR) hot leg with the diameter of 750 mm by using a volume of fluid (VOF) method implemented in the CFD software, FLUENT6.3.26. The calculated CCFL characteristics agreed well with known values including the UPTF data at 1.5 MPa. Sensitivity analyses for system pressures up to 8 MPa showed that the calculated CCFL characteristics in the Wallis diagram were slightly mitigated from 0.1 MPa to 1.5 MPa with increasing system pressure, but they did not change from 1.5 MPa to 8MPa. Using the CCFLs calculated in this study and values measured under air–water and steam–water conditions, a CCFL correlation and its uncertainty were derived. 相似文献
120.
Jun Hirouchi Shigekazu Hirao Jun Moriizumi Hiromi Yamazawa Atsuo Suzuki 《Journal of Nuclear Science and Technology》2013,50(1):48-55
A method to estimate the infiltration and surface run-off characteristics of radionuclides on three types of ground surface from gamma dose rate change due to rain has been developed. We proposed the estimation methods based on the differences in the dose rate increases between monitoring stations caused by different attenuation of gamma ray due to infiltration and by the different run-off characteristics. The gamma dose rate data used for the estimation were measured at near-by monitoring stations in which the ground type around the detector differed from each other. Rain events were selected by the criteria in which 214Pb and 214Bi deposition amounts are considered to be uniform with in the area in which objective monitoring stations are deployed. We also calculated the surface concentration considering both infiltration and surface run-off processes. As a result, it was shown that the calculated surface concentration was about 40% larger than that considering neither processes of the infiltration and surface run-off. 相似文献