全文获取类型
收费全文 | 752篇 |
免费 | 11篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 46篇 |
综合类 | 1篇 |
化学工业 | 174篇 |
金属工艺 | 17篇 |
机械仪表 | 26篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 45篇 |
轻工业 | 68篇 |
无线电 | 41篇 |
一般工业技术 | 175篇 |
冶金工业 | 85篇 |
原子能技术 | 16篇 |
自动化技术 | 61篇 |
出版年
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 22篇 |
2013年 | 37篇 |
2012年 | 39篇 |
2011年 | 47篇 |
2010年 | 23篇 |
2009年 | 28篇 |
2008年 | 36篇 |
2007年 | 34篇 |
2006年 | 16篇 |
2005年 | 24篇 |
2004年 | 18篇 |
2003年 | 27篇 |
2002年 | 29篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 17篇 |
1998年 | 34篇 |
1997年 | 33篇 |
1996年 | 20篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 16篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1970年 | 2篇 |
排序方式: 共有766条查询结果,搜索用时 0 毫秒
1.
Supaluk Krittanai Hathairat Buraphaka Seiichi Sakamoto Waraporn Putalun 《International Journal of Food Science & Technology》2021,56(11):5843-5852
Licorice is an herbal plant in the Leguminosae family, and its roots and rhizomes are used as sweeteners in food and confectionery products. Moreover, it has a distinct inflammatory activity. In the present study, a sample pre-treatment method to induce the deglycosylation of active metabolites in callus cultures of Glycyrrhiza inflata (GI) and Glycyrrhiza glabra (GG) was developed. The results of the method evaluation showed the biotransformation of ononin to formononetin, a rare flavonoid found in trace amounts in licorice. The magnitude of enhancement was 3- and 19-fold in the GI and GG samples, respectively. Moreover, the anti-inflammatory activity assay showed that the potency of the sample pre-treatment group was higher than that of the untreated group because it exerted an enhanced suppression of cyclo-oxygenase 2 (COX-2), interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) gene expression. This is the first report on the anti-inflammatory activity of licorice callus, which has the potential to be utilised as a functional food for health promotion. These findings support the idea of using sample preparation to impart nutraceutical properties to plant products. 相似文献
2.
Theoretical investigations have been carried out to predict the non-axisymmetric buckling seen in the throat of circular elastic-plastic tubes subjected to a nosing operation along a frictionless conically shaped die. The buckling points and associated modes are determined by Hill's bifurcation theory in conjunction with a non-axisymmetric buckling mode. The results show that increasing the die semi-angle and the tube thickness or decreasing the material work-hardening rate are always beneficial to improve the buckling limit. The associated critical buckling mode number generally decreases as the tube thickness increases and does not depend drastically on the die semiangle nor on the hardening rate. The effect of the average r value is substantial and the buckling limit is improved when the r value reduces. Part of the present results predict well the results observed in existing experimental work. 相似文献
3.
4.
5.
Hitoshi Kurokawa Taku Nakayama Yasunori Kobayashi Ken Suzuki Mutsumi Takahashi Seiichi Takami Momoji Kubo Naotsugu Itoh Parasuraman Selvam Akira Miyamoto 《Catalysis Today》2003,82(1-4):233-240
A modified Monte Carlo (MC) simulation was performed to investigate the hydrogen absorption behavior in Pd and Pd–Ag alloys of the composition PdxAg1−x (x=0.7–0.8) under H2 pressure (0.1 MPa) at different temperatures. The present method employed can consider the dissociative adsorption of hydrogen molecule and the subsequent absorption of hydrogen atom by formalizing the relationship between the pressure of hydrogen molecule and hydrogen atom. The potential parameters were determined to reproduce the solution enthalpy of hydrogen in pure metals. The results are in good agreement with experimental findings as well as previous theoretical studies. We confirmed that our method is useful to simulate the absorption of hydrogen in metals and alloys. 相似文献
6.
To evaluate an association between Helicobacter pylori (H. pylori) infection and chronic atrophic gastritis (CAG), an established precursor of gastric cancer, we performed a cross-sectional study using IgG antibody against H. pylori and pepsinogens of blood donors in four prefectures in Japan. Although a geographic correlation between the age-adjusted prevalence rates for H. pylori infection and those for CAG was not seen, the age-adjusted odds ratios (OR) of H. pylori infection for CAG were high in each area (around five for men and from four to 12.6 for women). The association between them weakened with advancing age; the ORs in the youngest age group (16-29 yrs) and in the oldest age group (50-64 yrs) were 12.5 and 2.8 for men, and 11.5 and 5.2 for women, respectively. These findings suggest that H. pylori infection is strongly associated with CAG, while there are some other factors interacting in the development of CAG. A prospective cohort study in which CAG and H. pylori infection are taken into account will be necessary to assess the risks of gastric cancer. 相似文献
7.
Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection with high morbidity and mortality rates. Its occurrence in the head and neck region is uncommon, the majority of reported cases being limited to involvement of the neck, usually from infections of dental or pharyngeal origin. Involvement of the face from NF is rare; only 35 such cases have been reported in the literature since 1960. It is not only associated with a high mortality but can also result in severe disfigurement of the face, posing challenging reconstructive problems. Successful management of facial NF requires early diagnosis, prompt institution of broad spectrum antibiotics, aggressive surgical debridement to control the infection, and reconstruction of the resultant soft tissue defects. This report describes four additional cases of facial necrotizing fasciitis. One of the four patients died as a result of sepsis and multi-organ system failure. Two of the three surviving patients had significant facial disfigurement. A comprehensive review of the facial NF cases reported in the literature is also provided. Based on our experience with facial NF and the results of all previous case reports, the clinical manifestations, pathogenesis, and management of this disease are discussed. 相似文献
8.
Double oxides of Rh and Ni have been prepared by chemical mixing methods. Silica-supported and unsupported RhNbO4 and NiNb2O6 catalysts exhibited strong metal-oxide interaction behaviors in ethane hydrogenolysis activities after the decomposition of the double oxides by H2 reduction at 500°C. Silica-supported and zeolite-supported RhVO4 catalysts showed high activity and selectivity for dehydrogenation of cyclohexane after the decomposition in H2. The double-oxide catalyst systems can be used as starting materials to obtain high-performance metal catalysts (redispersion of metals by H2 reduction and regeneration of catalysts by calcination at a high temperature). 相似文献
9.
Summary The rate constants for intramolecular excimer formation, kDM, of poly(α-methylstyrene) with different molecular weight were determined by using picosecond pulse radiolysis. Values of
kDM for poly(α-methylstyrene) are a little smaller than those for polystyrene with nearly same molecular weight. It appears to
be mainly due to steric hindrance by methyl substituent of main chain. 相似文献
10.
To support disabled people to use remote controllers, several biological signals are used. The tooth-touch is one of desirable biological signals. This is because it is the simple and natural human behavior. However, a sophisticated signal processing to extract only the tooth-touch sound is needed since the tooth-touch sound is mixed with the voice sound. This paper proposes a lightweight sensing method extracting the tooth-touch without a sophisticated signal processing to eliminate only voice sound from the sound wave in which tooth-touch and voice are mixed. Instead of the audible sound wave, proposal uses a shock wave (i.e., ultrasonic wave) which is generated when the upper tooth and the lower tooth hit each other. Using the shock wave generated to detect the tooth-touch, a trivial high-pass filter can eliminate only voice sound in the lower frequency domain than in the ultrasonic domain including the tooth-touch. Through a preliminary experiment that uses a conventional microphone and well-known digital high-pass filter, we show that the used electret microphone can sense the tooth-touch as ultrasonic wave and the high-pass filter can extract only tooth-touch. Then, we show some robustness of our method by using the sound waves including the voice and tooth-touch. In addition, we design the filtering hardware to implement a small and cheap system-on-chip achieving a real-time operation. Through the implementation of Field Programmable Gate Array, and the simulation, we show that our hardware is small and performs well for a real-time operation. 相似文献