全文获取类型
收费全文 | 126篇 |
免费 | 3篇 |
专业分类
化学工业 | 31篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 19篇 |
水利工程 | 1篇 |
无线电 | 2篇 |
一般工业技术 | 16篇 |
冶金工业 | 32篇 |
自动化技术 | 14篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2014年 | 2篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 6篇 |
2008年 | 8篇 |
2007年 | 1篇 |
2006年 | 7篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有129条查询结果,搜索用时 20 毫秒
41.
V Mais S Ajossa B Piras S Guerriero D Marongiu GB Melis 《Canadian Metallurgical Quarterly》1995,10(12):3133-3135
To evaluate the effectiveness of the oxidized regenerated cellulose absorbable barrier (Interceed, TC7) in the prevention of de-novo adhesion formation after laparoscopic myomectomy, a prospective and randomized study was performed at the Department of Obstetrics and Gynaecology of the University of Cagliari, Cagliari, Italy. A total of 50 pre-menopausal non-pregnant women, aged 23-42 years, who submitted to laparoscopic myomectomy from January 1993 to June 1994, were randomized to surgery alone (control group, n = 25) or surgery and oxidized regenerated cellulose barrier (Interceed group, n = 25). Neither group received any other treatment for adhesion prevention. A second-look laparoscopy was performed 12-14 weeks after laparoscopic myomectomy. The incidence of adhesion-free patients was assessed at second-look laparoscopy by an investigator not informed of the treatment. The numbers of adhesion-free patients were three out of 25 (12%) in the control group and 15 out of 25 (60%) in the treatment group (P < 0.05). In conclusion, the oxidized regenerated cellulose absorbable barrier significantly reduced de-novo adhesion formation after laparoscopic myomectomy. 相似文献
42.
Proof planning is an application of AI planning to theorem proving that employs plan operators that encapsulate mathematical proof techniques. Many proofs require the instantiation of variables; that is, mathematical objects with certain properties have to be constructed. This is particularly difficult for automated theorem provers if the instantiations have to satisfy requirements specific for a mathematical theory, for example, for finite sets or for real numbers, because in this case unification is insufficient for finding a proper instantiation. Often, constraint solving can be employed for this task. We describe a framework for the integration of constraint solving into proof planning that combines proof planners and stand-alone constraint solvers. Proof planning has some peculiar requirements that are not met by any off-the-shelf constraint-solving system. Therefore, we extended an existing propagation-based constraint solver in a generic way. This approach generalizes previous work on tackling the problem. It provides a more principled way and employs existing AI technology. 相似文献
43.
Chimpanzees (Pan troglodytes) competed with a human for food. The human sat inside a booth, with 1 piece of food to her left and 1 to her right, which she could retract from her chimpanzee competitor's reach as needed. In Experiment 1, chimpanzees could approach either side of the booth unseen but then had to reach through 1 of 2 tunnels (1 clear, 1 opaque) for the food. In Experiment 2, both tunnels were clear and the human was looking away, but 1 of the tunnels made a loud noise when it was opened. Chimpanzees preferentially reached through the opaque tunnel in the first study and the silent tunnel in the second, successfully concealing their taking of the food from the human competitor in both cases. These results suggest that chimpanzees can, in some circumstances, actively manipulate the visual and auditory perception of others by concealing information from them. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
44.
Increase in meso-prefrontal dopaminergic activity after stimulation of CB1 receptors by cannabinoids
The intravenous administration of the psychoactive constituent of marijuana, delta9-tetrahydrocannabinol (delta9-THC) (62.5-1000 microg/kg), and the synthetic cannabinoid agonist WIN 55212,2 (WIN) (62.5-500 microg/kg), produced a dose-related increase in the firing rate and burst firing in the majority of antidromically identified meso-prefrontal dopaminergic neurons. In a restricted number of neurons (n=4), WIN administration did not increase firing rate but produced an increment of bursting activity. These effects of the cannabinoids were reversed by the intravenous administration of SR 141716 A, a selective cannabinoid antagonist (1 mg/kg), per se ineffective to modify the electrical activity of dopaminergic neurons. The results indicate that stimulation of cannabinoid CB1 receptors produces an activation of meso-prefrontal dopaminergic transmission. Considering that supranormal stimulation of D1 dopamine receptors in the prefrontal cortex has been shown to impair working memory, the present results suggest that the negative effects of cannabinoids on cognitive processes might be related to the activation of dopaminergic transmission in the prefrontal cortex. 相似文献
45.
Dog collars made of PVC plastic impregnated with the pyrethroid insecticide deltamethrin at 40 mg/g were investigated for their protective efficacy against phlebotomine sandflies. Collared dogs were kept separately (two untreated control dogs lived together) in outdoor enclosures, each with a kennel, in the Cévennes, southern France. To measure sandfly mortality and anti-feeding effects due to the deltamethrin-impregnated collars worn continuously by the dogs for up to 8 months, each dog was periodically sedated and exposed for 2h to 150-200 laboratory-reared Phlebotomus perniciosus females (plus c. 25 males) inside a net (1.2 m square, 1.8 m high) indoors. After dogs were removed from the nets, allowed to recover and returned to their kennels, any dead sandflies were collected from inside the net and counted. Surviving flies were kept overnight, then scored according to whether they were still alive or dead, unfed or blood-fed. From tests 2, 3, 4, 13, 20, 26 and 34 weeks after the dogs began wearing collars, the overall numbers of blood-fed female sandflies recaptured were 75 from two dogs with collars, compared with 1911 from two collarless dogs. Thus, for every 100 flies which fed on collarless dogs, only 4 fed on collared dogs, i.e. the collars protected dogs from 96% of the bites and this activity was maintained for up to 34 weeks. During the same period, the percentage of recaptured female sandflies that had fed on collared dogs was 0-12% compared to 55-95% on collarless dogs. Immediately after dogs were taken out of the nets, 21-60% of flies confined with the collared dogs were found dead, compared to 0-12% with the controls. It is concluded that, at least in the Mediterranean subregion, this insecticidal collar would protect a dog from the majority of sandfly bites and retain a killing effect for a complete sandfly season. Moreover, it seems likely that the use of collars on all dogs in a focus of Leishmania infantum would reduce contact between sandfly vectors and canine reservoir hosts sufficiently to diminish the risk of infection for humans as well as dogs. 相似文献
46.
Melis Arin Gultekin Goller Jef Vleugels Kim Vanmeensel 《Journal of Materials Science》2008,43(5):1599-1611
Tetragonal ZrO2 polycrystalline (TZP) ceramics with varying yttria and ceria content (2–3 mol%) and distribution (coated or co-precipitated),
and varying second phase content Al2O3 were prepared and investigated by means of microstructural analysis, mechanical properties, and hydrothermal stability, and
ZrO2-based composites with 35–60 vol% of electrical conductive TiN particles were developed. The effects of stabilizer content
and means of addition, powder preparation, sintering conditions, and grain size have been systematically investigated. Fully
dense Y-TZP ceramics, stabilized with 2–3 mol% Y2O3, 2 wt% Al2O3 can be achieved by hot pressing at 1,450 °C for 1 h. The hydrothermal stability increased with increasing overall yttria
content. The jet-milled TiN powder was used to investigate the ZrO2–TiN composites as function of the TiN content. The experimental work revealed that fully dense ZrO2–TiN composites, stabilized with 1.75 mol% Y2O3, 0.75 wt% Al2O3, and a jet-milled TiN content ranging from 35 to 60 vol% could be achieved by hot pressing at 1,550 °C for 1 h. Transformation
toughening was found as the primary toughening mechanism. The decreasing hardness and strength could be attributed to an increasing
TiN grain size with increasing TiN content, whereas the decreasing toughness might be due to the decreasing contribution of
transformation toughening from the tetragonal to monoclinic ZrO2 phase transformation. The E modulus increases linearly with increasing TiN content, whereas the hydrothermal stability increases
with addition of TiN content. 相似文献
47.
Castiglioni S Bagnati R Melis M Panawennage D Chiarelli P Fanelli R Zuccato E 《Water research》2011,45(16):5141-5150
The most relevant human urinary metabolites of cocaine (nine metabolites) were measured in urban wastewater in Italy and USA. A novel analytical method based on liquid chromatography tandem mass spectrometry allowed the identification of ecgonine, ecgonine methyl ester and the pyrolytic derivatives of cocaine in untreated wastewater. The aim of this study was to verify whether the pattern of cocaine metabolites in wastewater reflected the human excretion profile in urine. The performance of the method was good, with recoveries higher than 60% and limits of quantifications in the low ng/L range. The stability in untreated wastewater was assessed for all metabolites and the best storage condition resulted freezing samples immediately after collection and keep them frozen until analysis. All the selected compounds were measured in wastewater at concentrations up to 1.5 μg/L and their weekly loads were calculated during a five weeks monitoring campaign in Milan (Italy). The profiles of cocaine metabolites in wastewater matched with those in human urine reported in the literature, suggesting that measures in wastewater reflect the real human excretion and that wastewater analysis is suitable for assessing drug consumption. Benzoylecgonine was confirmed as the best target for estimating cocaine use by wastewater analysis, while cocaine itself should not be considered because its amount in wastewater is affected by other environmental sources such as transport, handling and consumption. Results suggested that the measurement of other metabolites in combination with benzoylecgonine might reflect 60% of an administered dose of cocaine providing also information on different patterns of use. 相似文献
48.
49.
50.
The influence of the structure and the temperature on the Conductive Polymer Composites (CPC) properties has been studied. The investigated CPC are based on homo- and heterogeneous polymer blends of high density polyethylene, polybutylene terephthalate and poly(m-xylene adipamide), filled with dispersed silver nanoparticles (Ag). It is shown that by the appropriate use of the immiscible polymers blends the percolation threshold can be decreased twice, what significantly reduces costs and keeps better mechanical properties. Additionally, it was found that depending on the choice of CPC structure the commutation temperature from a conducting state to an insulating state can be observed between 45 and 180 °C. The observed high intensity of Positive Temperature Coefficient (PTC) effect, i.e. a sharp (narrow temperature range) and strong (10 orders of magnitude) resistivity increase, makes such composites promising for current limiting devices and temperature sensors. 相似文献