全文获取类型
收费全文 | 838篇 |
免费 | 39篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 878篇 |
出版年
2023年 | 3篇 |
2022年 | 19篇 |
2021年 | 18篇 |
2020年 | 17篇 |
2019年 | 22篇 |
2018年 | 22篇 |
2017年 | 23篇 |
2016年 | 25篇 |
2015年 | 19篇 |
2014年 | 30篇 |
2013年 | 48篇 |
2012年 | 29篇 |
2011年 | 47篇 |
2010年 | 34篇 |
2009年 | 41篇 |
2008年 | 36篇 |
2007年 | 37篇 |
2006年 | 33篇 |
2005年 | 31篇 |
2004年 | 24篇 |
2003年 | 34篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 14篇 |
1999年 | 18篇 |
1998年 | 64篇 |
1997年 | 35篇 |
1996年 | 25篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1976年 | 7篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1938年 | 1篇 |
排序方式: 共有878条查询结果,搜索用时 15 毫秒
31.
The ever-increasing demand for higher data rates in wireless commutations provides a rationale for small cells deployment. While the physical and technological aspects of small-cell networks have been extensively studied in recent years, the economic analysis has received much less attention. We focus on the economic rationale for a small-cell service provider (SSP) operating a market where an incumbent macrocell service provider (MSP) exists, and competition develops. We analyze such scenario for the case of fixed users by means of Game Theory, specifically through a two-stage game: in the first stage each service provider posts its price according to a Stackelberg game where the MSP is the leader and the SSP is the follower; and, in the second stage, each user chooses both which provider to subscribe to and the optimal amount of bandwidth. A subgame perfect Nash equilibrium is used as a solution concept, and it is derived analytically. We show that the SSP has an incentive to operate in the market and its profit gets higher as SSP’s resources increase. Furthermore, users benefit from SSP’s operation, which may provide a rationale for a regulatory authority to grant the SSP access to the market, despite the fact that MSP’s profit is harmed. Finally, we identify two modes of operation of the system, which depend on the SSP coverage: one where SSP’s deployment is limited and the MSP strategy is not affected by SSP competition and takes only the users outside the SSP coverage; and another, where the SSP covers a large area and the MSP competes against the SSP taking a fraction of the users inside the small cells. 相似文献
32.
Dolz Manuel F. Alventosa Fran J. Alonso-Jordá Pedro Vidal Antonio M. 《The Journal of supercomputing》2019,75(3):1470-1482
The Journal of Supercomputing - There exist problems in the field of digital signal processing, such as filtering of acoustic signals that require processing a large amount of data in real time.... 相似文献
33.
Dr. Mimouna Madaoui Dr. Olivier Vidal Albert Meyer Mathieu Noël Prof. Dr. Jean-Marie Lacroix Dr. Jean-Jacques Vasseur Prof. Dr. Alberto Marra Dr. François Morvan 《Chembiochem : a European journal of chemical biology》2020,21(23):3433-3448
Galacto- and fuco-clusters conjugated with one to three catechol or hydroxamate motifs were synthesised to target LecA and LecB lectins of Pseudomonas aeruginosa (PA) localised in the outer membrane and inside the bacterium. The resulting glycocluster–pseudosiderophore conjugates were evaluated as Trojan horses to cross the outer membrane of PA by iron transport. The data suggest that glycoclusters with catechol moieties are able to hijack the iron transport, whereas those with hydroxamates showed strong nonspecific interactions. Mono- and tricatechol galactoclusters ( G1C and G3C ) were evaluated as inhibitors of infection by PA in comparison with the free galactocluster ( G0 ). All of them exhibited an inhibitory effect between 46 to 75 % at 100 μM, with a higher potency than G0 . This result shows that LecA localised in the outer membrane of PA is involved in the infection mechanism. 相似文献
34.
35.
Fructose overfeeding in first‐degree relatives of type 2 diabetic patients impacts energy metabolism and mitochondrial functions in skeletal muscle 下载免费PDF全文
36.
Phenyl‐γ‐valerolactones,flavan‐3‐ol colonic metabolites,protect brown adipocytes from oxidative stress without affecting their differentiation or function 下载免费PDF全文
37.
Alberto Gomez-Barea Susanna Nilsson Fernando Vidal Barrero Manuel Campoy 《Fuel Processing Technology》2010,91(11):1624-1633
Experiments were carried out in a laboratory fluidized bed (FB) to characterize the devolatilization behavior of wood and various wastes at temperatures applicable to FB gasification and combustion, i.e. 750-900 °C. The fuels tested were pellets made of wood, meat and bone meal, and compost (from municipal solid wastes), as well as dried granulates of sewage sludge (DSS). Determination of yields of char, condensate and light gas, as well as the composition of the gas and the time of devolatilization during the pyrolysis of single fuel batches was made. A simple model was developed to analyze the mode of conversion of a single wood pellet and DSS granulate, giving insight on the controlling mechanisms during devolatilization. The devolatilization kinetics of DSS was determined by tests using fine granulates. The model was successfully applied to simulate the conversion of large DSS granulates and wood pellets under the whole range of temperatures analyzed. 相似文献
38.
Dr. Marine Blanchet Dr. Diane Borselli Dr. Anne Rodallec Dr. Franck Peiretti Nicolas Vidal Dr. Jean‐Michel Bolla Dr. Carole Digiorgio Kelly R. Morrison Prof. William M. Wuest Dr. Jean Michel Brunel 《ChemMedChem》2018,13(10):1018-1027
The emergence of multidrug‐resistant bacteria and pathogens has created an urgent need for the development of new antibiotics. Herein we report our investigations into the broad‐spectrum activity of an easily prepared water‐soluble polyaminosterol compound, namely claramine A1, against both drug‐sensitive and drug‐resistant Gram‐negative and Gram‐positive bacterial strains. We also report its peculiar mechanism of action, which differs from that of all the other well‐known classes of antibiotics, toward Gram‐negative and Gram‐positive bacteria. Given their low cytotoxicity, this class of compounds based on claramine A1 could constitute an effective response to combat the emergence of multidrug‐resistant bacteria and nosocomial diseases. 相似文献
39.
By thermally treating a commercial cellulose in ethylene glycol, celluloses of controlled low degree of polymerization, DPr = 1000 to 70, can be derived. Two general behaviors are observed in the range studied. At first, the depolymerization reaction is predominant down to a DP equal to 130. Beyond this level, the depolymerization process leads to extensive solubilization of the cellulose. The treated celluloses have been analyzed by X-ray diffraction, FTIR, TGA, elemental analysis and enzymatic hydrolysis. No chemical change of the cellulose could explain the two different behaviors. A physical modification in the form of depolymerization and destructuration is suspected. 相似文献
40.
Easy extrusion of honeycomb-shaped monoliths using Moroccan natural clays and investigation of their dynamic adsorptive behavior towards VOCs 总被引:2,自引:0,他引:2
T. Chafik S. Harti G. Cifredo J.M. Gatica H. Vidal 《Journal of hazardous materials》2009,170(1):87-95
In the present work, honeycomb-shaped monoliths were easily extruded using local natural clays without the need of chemical binders. This finding allows significant cost reduction, in terms of not only additives and solvents but also the energy consumption required for their elimination by thermal treatment. The extruded monoliths were subject to mechanical strength testing in addition to the study of their thermal behavior, structural and textural properties. Moreover, one of their potential uses as VOCs adsorbents was evaluated in comparison with conventional packed bed by investigating their dynamic adsorptive and desorption behavior towards a model VOC of o-xylene type. 相似文献