全文获取类型
收费全文 | 1211篇 |
免费 | 18篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 1230篇 |
出版年
2022年 | 10篇 |
2021年 | 25篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 12篇 |
2014年 | 22篇 |
2013年 | 46篇 |
2012年 | 40篇 |
2011年 | 44篇 |
2010年 | 35篇 |
2009年 | 45篇 |
2008年 | 31篇 |
2007年 | 40篇 |
2006年 | 42篇 |
2005年 | 31篇 |
2004年 | 33篇 |
2003年 | 41篇 |
2002年 | 29篇 |
2001年 | 23篇 |
2000年 | 28篇 |
1999年 | 38篇 |
1998年 | 89篇 |
1997年 | 70篇 |
1996年 | 62篇 |
1995年 | 24篇 |
1994年 | 31篇 |
1993年 | 29篇 |
1992年 | 18篇 |
1991年 | 18篇 |
1990年 | 19篇 |
1989年 | 22篇 |
1988年 | 9篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 16篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1979年 | 7篇 |
1978年 | 13篇 |
1977年 | 8篇 |
1976年 | 11篇 |
1974年 | 7篇 |
1973年 | 9篇 |
1972年 | 12篇 |
1969年 | 6篇 |
1967年 | 7篇 |
排序方式: 共有1230条查询结果,搜索用时 0 毫秒
1.
2.
Hydrothermal Synthesis and Low-Temperature Sintering of Zinc Gallate Spinel Fine Particles 总被引:1,自引:0,他引:1
Nanosized powders of single-phase zinc gallate (ZnGa2 O4 ) spinel were hydrothermally synthesized from solutions in the presence of NaOH over the pH range of 1.9 to 7.0 and from solutions above pH 7.0, i.e., the very basic medium (pH of 13.85), by removing the residual ZnO phase by washing with aqueous H2 SO4 from the precipitate mixtures of zinc gallate spinel particles and ZnO. A very wide compositional range (Zn/2Ga = 0.705–1.157) of zinc gallate spinel solid solutions could be hydrothermally synthesized in the form of nanosized particles from acid and very basic mediums (pH of 2.4–13.85) in the presence of NaOH. These hydrothermally synthesized spinel powders showed good sinterability and almost full densification at 1100°C for 1 h. Dense sintered bodies consisting of single-phase zinc gallate spinel were fabricated at 1100°C using zinc gallate spinel powders having almost stoichiometric composition formed from the solution at pH 9.95 in the presence of aqueous ammonia. 相似文献
3.
Yukihisa Tanaka Jiro Hirano Tadashi Funada 《Journal of the American Oil Chemists' Society》1992,69(12):1210-1214
In an attempt to concentrate the content of DHA (docosahexaenoic acid) in a glyceride mixture containing triglyceride, diglyceride
and monoglyceride, fish oil was hydrolyzed with six kinds of microbial lipase. After the hydrolysis, free fatty acid was removed
and fatty acid components of the glyceride mixtures were analyzed. When the hydrolysis withCandida cylindracea lipase was 70% complete, the DHA content in the glyceride mixture was three times more than that in the original fish oil.
The EPA (eicosapentaenoic acid) content became almost 70% of the original fish oil. Hydrolysis with other lipases did not
result in an increase in the DHA content in the glyceride mixtures. Hydrolysis of DHA-rich tuna oil (DHA content is about
25%) withCandida cylindracea lipase resulted in 53% DHA in the glyceride mixture. The EPA content, however, remained close to that of the original tuna
oil. In this report, the acyl chain specificity of lipases is evaluated in terms of hydrolysis resistant value (HRV). HRV
is the ratio between the DHA contents in the glyceride mixture of hydrolyzed oil and original oil. HRV clearly indicates differences
in hydrolysis between DHA and other fatty acids (e.g., saturated and monoenoic acids). 相似文献
4.
Fe3C film, which is a promising new magnetic recording material, can be synthesized by r.f. magnetron sputtering. Several graphite plates were attached to an iron plate to adjust the area of a composite target for the control of film composition. The crystalline phases in a film changed from Fe-C solid solution to Fe3C with increasing substrate temperature from 350 °C and above. Sputtering at an argon pressure of 5 Pa was favourable for the formation of crystalline Fe3C film. All Fe3C films showed in-plane magnetization. The saturation magnetization of the film was around 100–120 e.m.u. g–1 regardless of the deposition conditions. The coercivity of the films increased from 1 Oe to 250 Oe with increasing substrate temperature, and the coercivity remained constant at 250 Oe at 350 °C, regardless of argon pressure. 相似文献
5.
6.
7.
Hamada H. Hirano K. Goda N. Abe H. Hasegawa I. Okita Y. Arioka S. Niina T. 《Electronics letters》1994,30(20):1719-1720
The off state current for polysilicon thin-film transistors for pixels in LCDs has been successfully reduced by introducing a polysilicon buffer layer between a polysilicon active layer fabricated by solid-phase-crystallisation (SPC) and a fused quartz substrate. Off-slate current of less than 1 pA under Vgs=-25 V at Vds=3 V was obtained for n-channel single-gate coplanar transistors using the buffer layer (400 Å) 相似文献
8.
T Miwa K Miura S Miyakawa S Narayama H Hirano K Kanai 《Canadian Metallurgical Quarterly》1993,32(3):211-213
AIMS AND BACKGROUND: The usefulness of monoclonal antibodies that recognize markers of neoplastic lesions in complementing conventional cytology was evaluated by the avidin-biotin-peroxidase complex, indirect immunoperoxidase technique. METHODS: In order to enhance the sensitivity of the traditional method, a pool of seven combined monoclonal antibodies (Pool C7), which reacts specifically with cells of epithelial origin and is able to distinguish between mesothelial and malignant cells, was tested on cytologic smears of 262 serous effusions. The effusions were benign or neoplastic, mainly from breast, ovary and lung cancers. RESULTS: Immunocytochemical method showed an 100% specificity and 100% of predictivity whereas the sensitivity was 98%, 96% and 95% for breast ovarian and lung carcinomas, respectively. CONCLUSIONS: The results demonstrated that the pool when used together with conventional methods, is useful in analysis of serous effusions in diagnostic investigations. 相似文献
9.
K Iguchi M Hamatake R Ishida Y Usami T Adachi H Yamamoto K Koshida T Uchibayashi K Hirano 《Canadian Metallurgical Quarterly》1998,253(3):766-770
Endothelin-1 (ET-1) is a cardiovascular peptide that binds to two distinct receptors, ET(A) and ET(B), resulting in systemic and regional vasoconstriction, alteration in sodium excretion, mitogenesis, and release of other vasoactive peptides such as atrial natriuretic peptide (ANP). A role for ET-1 has been proposed in congestive heart failure (CHF) based on the increase in circulating ET-1 in this cardiovascular disease state. The present study determined the cardiorenal and endocrine responses to chronic selective oral ETA antagonism in experimental CHF. Two groups of conscious dogs underwent 21 days of pacing-induced CHF. These groups included a control untreated group (n = 6) and a group that received an orally active ET(A) receptor antagonist (A-127722, Abbott Pharmaceuticals, 5 mg/kg PO bid, n = 6). Each group was studied at baseline before the onset of CHF and after 14 and 21 days of CHF. Compared with the CHF control group, the ET(A) receptor antagonism group at 14 days of CHF showed lower mean arterial pressure and systemic vascular resistance. Similarly, ET(A) receptor antagonism markedly attenuated the increase in circulating ANP despite similar atrial pressures. At 21 days of CHF, ET(A) receptor antagonism lowered pulmonary artery pressure, pulmonary vascular resistance, and systemic vascular resistance in association with a higher cardiac output. Plasma ANP remained suppressed. Despite the lower mean arterial pressure and circulating ANP in the ET(A) receptor antagonist group, the absolute decrease in sodium excretion from baseline was less compared with the untreated CHF control group. The present investigation supports the conclusion that endogenous ET-1 participates in the systemic and pulmonary vasoconstriction, the elevation of ANP, and the sodium retention that characterize this model of experimental CHF, suggesting a potential therapeutic role for ET(A) receptor antagonism in CHF. 相似文献
10.
Takashi Hayashi Makoto Mihoya Iwao Yamai Hajime Saito Shin-Ichi Hirano 《Journal of Materials Science》1987,22(4):1305-1309
Needle-like or wool-like Al2O3 whiskers can be grown on a substrate by the hydrolysis of aluminium fluoride vapour. Effects of the growth conditions on the morphology of the crystals and growth processes of the whisker were investigated, and the optimum growth condition of whiskers was examined. Adequate vapour pressure conditions of the reactant gases for the growth of the wool-like whisker were found to be
. Aluminium oxyfluoride was assumed to be the most probable intermediate species for the growth of Al2O3 whiskers. A variety of crystal morphologies are also shown and described with respect to the experimental conditions. 相似文献