全文获取类型
收费全文 | 1525篇 |
免费 | 35篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 70篇 |
综合类 | 4篇 |
化学工业 | 463篇 |
金属工艺 | 31篇 |
机械仪表 | 32篇 |
建筑科学 | 40篇 |
能源动力 | 50篇 |
轻工业 | 82篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 126篇 |
一般工业技术 | 300篇 |
冶金工业 | 234篇 |
原子能技术 | 33篇 |
自动化技术 | 101篇 |
出版年
2021年 | 25篇 |
2020年 | 9篇 |
2019年 | 16篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 17篇 |
2015年 | 18篇 |
2014年 | 34篇 |
2013年 | 55篇 |
2012年 | 42篇 |
2011年 | 63篇 |
2010年 | 53篇 |
2009年 | 59篇 |
2008年 | 51篇 |
2007年 | 45篇 |
2006年 | 62篇 |
2005年 | 55篇 |
2004年 | 55篇 |
2003年 | 55篇 |
2002年 | 43篇 |
2001年 | 34篇 |
2000年 | 30篇 |
1999年 | 49篇 |
1998年 | 92篇 |
1997年 | 78篇 |
1996年 | 66篇 |
1995年 | 28篇 |
1994年 | 38篇 |
1993年 | 36篇 |
1992年 | 17篇 |
1991年 | 20篇 |
1990年 | 26篇 |
1989年 | 19篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 16篇 |
1983年 | 16篇 |
1982年 | 18篇 |
1981年 | 14篇 |
1980年 | 15篇 |
1979年 | 18篇 |
1978年 | 16篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 9篇 |
1972年 | 13篇 |
排序方式: 共有1569条查询结果,搜索用时 15 毫秒
1.
2.
Shingo Hirano Akio Kawabata Masaru Yoshinaka Ken Hirota Osamu Yamaguchi 《Journal of the American Ceramic Society》1995,78(5):1414-1416
A compound denoted as (Ce0.75 Zr0.25 )O2 (Ce, ZrO8 ) is formed near room temperature from cerium and zirconium nitrates using hydrazine monohydrate. It has a cubic unit cell with a = 0.5342 nm. Characterization of powders heated to various temperatures at 10°C/min demonstrates that the specific surface area does not decrease below 20 mVg until >1000°C. 相似文献
3.
Nobuhiro Kumada Nobuo Ozawa Nobukazu Kinomura Fumio Muto 《Materials Research Bulletin》1985,20(5):583-589
Pyrochlores of A1?xHxTaO3·nH2O (A=Na,K) were prepared under the hydrothermal conditions. The values of x for these compounds were increased from 0.3 to 0.5 for A=Na and from 0.2 to 0.5 for A=K by treatment with the distilled water. The compounds with x<0.5 were decomposed to a mixture of NaTaO3 and Na2Ta4O11 for A=Na, or to a mixture of KTaO3 and a tetragonal tungsten bronze phase, and those with x=0.5 to a single phase of A2Ta4O11 at elevated temperatures. Below the decomposition temperatures, defect pyrochlores with oxygen vacancies, , were produced. They were hygroscopic, and in the case of A=K and x=0.5 the original phase was recovered by leaving in air for several hours. 相似文献
4.
Fumio Negoro 《Knowledge》2003,16(7-8):383-397
The purpose of our study is to build up relationships between requirement and source programs with our originally thought-out rules. When other rules to be derived from these original rules are applied to software development, even a single instruction in a programming language could be determined, and the program would satisfy the requirement. More specifically speaking, these rules will turn into a formula or a prototype of software programs. Hence, when the variables in the requirement are placed in the formula, we can get a required program in an automatic way. 相似文献
5.
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
6.
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
7.
Dural caroticocavernous fistula with both ophthalmic arteries arising from middle meningeal arteries
A 60-year-old woman presented with a dural caroticocavernous fistula (CCF) in whom both by ophthalmic arteries arose from the middle meningeal arteries instead of from the internal carotid arteries. Transarterial embolisation of the CCF was contraindicated because of the risk of blindness. Transvenous coil embolisation was therefore performed. Bilateral origin of the ophthalmic artery from the middle meningeal artery is extremely rare. 相似文献
8.
C Abe S Hirano K Wakazono T Mase R Yamamoto M Matsufuji N Sakata N Agata H Iguchi M Ishizuka 《Canadian Metallurgical Quarterly》1995,17(5-6):175-180
Cytogenin, 8-hydroxy-3-hydroxymethyl-6-methoxyisocoumarin, has low cytotoxicity on murine and human tumour cells in vitro. It augments or suppresses phagocytosis of macrophages and lymphocyte proliferation. It has been reported that cytogenin has a potent inhibitory effect clinically on adjuvant arthritis in Lewis rats and on type II collagen-induced arthritis in DBA/1J mice. Our experimental findings provide evidence that cytogenin has beneficial effects on spontaneous polyarthritis in MRL/1 mice and pristane-induced arthritis in DBA/1J mice. The results suggest that the mode of the anti-arthritic action of cytogenin is different from those of NSAIDs; although the precise mode of action remains unclear, cytogenin may become an excellent therapeutic agent for rheumatoid arthritis. 相似文献
9.
10.
Fumio Matsumura Masayuki Fujita Masanao Shimizu 《Electrical Engineering in Japan》1991,111(7):117-124
This paper presents the robust control design of a magnetic suspension system for a flexible beam which is a simplified model of an elastic rotor in a magnetic bearing system. To stabilize this magnetic suspension system which is unstable in nature, the Hinfin; control theory is applied for a design of the control system. To apply the Hinfin; control theory, a statespace model of an augmented plant with frequency-weighting functions is constructed. This augmented plant has two inputs which are the exogenous inputs and the control inputs, and two outputs which are the sensor outputs and the regulated outputs. Here we consider the mixed sensitivity problem. The Hinfin; controller is implemented by a digital controller which is able to execute the computations very quickly. For the evaluation of the control performance, several experiments are made. The robustness of the closed-loop system is confirmed by the experimental results. The result of this study is useful for the control design of a magnetic bearing system. 相似文献