全文获取类型
收费全文 | 366篇 |
免费 | 34篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 116篇 |
金属工艺 | 4篇 |
机械仪表 | 10篇 |
建筑科学 | 8篇 |
能源动力 | 4篇 |
轻工业 | 48篇 |
水利工程 | 4篇 |
无线电 | 25篇 |
一般工业技术 | 65篇 |
冶金工业 | 65篇 |
原子能技术 | 4篇 |
自动化技术 | 44篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 18篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 22篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 19篇 |
2012年 | 26篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 15篇 |
2008年 | 11篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 16篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 24篇 |
1997年 | 15篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有400条查询结果,搜索用时 78 毫秒
1.
Alex Buchberger Harpinder Saini Kiarash Rahmani Eliato Azadeh Zare Ryan Merkley Yang Xu Julio Bernal Robert Ros Mehdi Nikkhah Dr. Nicholas Stephanopoulos 《Chembiochem : a European journal of chemical biology》2021,22(10):1755-1760
Biomaterials with dynamically tunable properties are critical for a range of applications in regenerative medicine and basic biology. In this work, we show the reversible control of gelatin methacrylate (GelMA) hydrogel stiffness through the use of DNA crosslinkers. We replaced some of the inter-GelMA crosslinks with double-stranded DNA, allowing for their removal through toehold-mediated strand displacement. The crosslinks could be restored by adding fresh dsDNA with complementary handles to those on the hydrogel. The elastic modulus (G’) of the hydrogels could be tuned between 500 and 1000 Pa, reversibly, over two cycles without degradation of performance. By functionalizing the gels with a second DNA strand, it was possible to control the crosslink density and a model ligand in an orthogonal fashion with two different displacement strands. Our results demonstrate the potential for DNA to reversibly control both stiffness and ligand presentation in a protein-based hydrogel, and will be useful for teasing apart the spatiotemporal behavior of encapsulated cells. 相似文献
2.
Kylie B. Manning Nicholas Wyatt Lindsey Hughes Adam Cook Nicholas H. Giron Estevan Martinez Christopher G. Campbell Mathias C. Celina 《大分子材料与工程》2019,304(3)
The use of self‐assembling, pre‐polymer materials in 3D printing is rare, due to difficulties of facilitating printing with low molecular weight species and preserving their reactivity and/or functions on the macroscale. Akin to 3D printing of small molecules, examples of extrusion‐based printing of pre‐polymer thermosets are uncommon, arising from their limited rheological tuneability and slow reactions kinetics. The direct ink write (DIW) 3D printing of a two‐part resin, Epon 828 and Jeffamine D230, using a self‐assembly approach is reported. Through the addition of self‐assembling, ureidopyrimidinone‐modified Jeffamine D230 and nanoclay filler, suitable viscoelastic properties are obtained, enabling 3D printing of the epoxy–amine pre‐polymer resin. A significant increase in viscosity is observed, with an infinite shear rate viscosity of approximately two orders of magnitude higher than control resins, in addition to, an increase in yield strength and thixotropic behavior. Printing of simple geometries is demonstrated with parts showing excellent interlayer adhesion, unachievable using control resins. 相似文献
3.
Freddy A. Bernal Dr. Marcel Kaiser Prof. Dr. Bernhard Wünsch Prof. Dr. Thomas J. Schmidt 《ChemMedChem》2020,15(1):68-78
Protozoal infections are still a global health problem, threatening the lives of millions of people around the world, mainly in impoverished tropical and sub-tropical regions. Thus, in view of the lack of efficient therapies and increasing resistances against existing drugs, this study describes the antiprotozoal potential of synthetic cinnamate ester analogues and their structure-activity relationships. In general, Leishmania donovani and Trypanosoma brucei were quite susceptible to the compounds in a structure-dependent manner. Detailed analysis revealed a key role of the substitution pattern on the aromatic ring and a marked effect of the side chain on the activity against these two parasites. The high antileishmanial potency and remarkable selectivity of the nitro-aromatic derivatives suggested them as promising candidates for further studies. On the other hand, the high in vitro potency of catechol-type compounds against T. brucei could not be extrapolated to an in vivo mouse model. 相似文献
4.
The Multimode Resource‐Constrained Project Scheduling Problem for Repetitive Activities in Construction Projects 下载免费PDF全文
J. D. García‐Nieves J. L. Ponz‐Tienda A. Salcedo‐Bernal E. Pellicer 《Computer-Aided Civil and Infrastructure Engineering》2018,33(8):655-671
In construction projects, resource availability might limit the implementation of ideal schedules. Especially, when repetitive activities are involved, traditional resource‐constrained project scheduling problem (RCPSP) models fail to allocate the resource consumption in an efficient manner. Besides, actual models only provide local optimal solutions and do not incorporate activity acceleration routines. To fulfill this gap, partially, a mathematical optimization model, the multimode RCPSP for repetitive activities in construction projects, is proposed and solved to optimality; it takes into account acceleration routines under real construction scenarios using spreadsheets. The article shows a complete computational experimentation over a real construction project, considering several scenarios of resource availabilities and continuity conditions. The model allows analyzing the resources efficiency indexes comparing them to resource consumptions, continuity of activities, and objective functions that reveal that fragmented activities do not provide better resource efficiency outcomes. 相似文献
5.
Laura Cristóbal Andrade Miguel A. Bernal PampínM.C. Taboada Gómez Pastora M. Bello Bugallo 《Chemical Engineering Research and Design》2014
This paper proposes a methodology to improve the sustainability of industrial processes combining two tools: BAT Analysis and process simulation. Both tools are jointly applied to identify the IF of the analyzed process, so that the most appropriate candidate techniques from an inventory can be selected. The selected alternatives are tested in different scenarios that are evaluated using simulation, which would determine the configuration that best improves the sustainability of the process. The combination of both tools in an integrated methodology will help decision makers to select the most sustainable configuration for a given process. The methodology is validated in a case study: a hydrogen production plant. After analysing several scenarios where different candidate techniques are implemented, results show that the IF identified can be highly improved when the appropriate combination of BAT is applied. 相似文献
6.
7.
8.
Adverse effects of vitamin D deficiency on the Pi3k/Akt pathway and pancreatic islet morphology in diet‐induced obese mice 下载免费PDF全文
9.
Generalization of recommender systems: Collaborative filtering extended to groups of users and restricted to groups of items 总被引:1,自引:0,他引:1
Jesús Bobadilla Fernando OrtegaAntonio Hernando Jesús Bernal 《Expert systems with applications》2012,39(1):172-186
In this paper we present a collaborative filtering method which opens up the possibilities of traditional collaborative filtering in two aspects: (1) it enables joint recommendations to groups of users and (2) it enables the recommendations to be restricted to items similar to a set of reference items. By way of example, a group of four friends could request joint recommendations of films similar to “Avatar” or “Titanic”. In the paper, using experiments, we show that the traditional approach of collaborative filtering does not satisfactorily resolve the new possibilities contemplated; we also provide a detailed formulation of the method proposed and an extensive set of experiments and comparative results which show the superiority of designed collaborative filtering compared to traditional collaborative filtering in: (a) number of recommendations obtained, (b) quality of the predictions, (c) quality of the recommendations. The experiments have been carried out on the databases Movielens and Netflix. 相似文献
10.
Claudia Bernal Monica Mesa Ligia Sierra 《Materials science & engineering. C, Materials for biological applications》2012,32(6):1380-1385
Monomodal or bimodal porous silicas with large mesopores, constituted by particles or having a monolithic (block type) morphology, respectively, are synthesized using sodium silicate as siliceous species source, cetyltrimethylammonium bromide (CTAB) as pore template and ethyl acetate (EtAc) as pH modifier. The monomodal porosity is represented by 20–30 nm pores and the bimodal one by these pores and also macropores. These characteristics are modulated in function of the CTAB and EtAc concentrations as well as the pH and hydrothermal treatment. The role of these reagents upon the porosity is rationalized. The presence of high CTAB concentration and a rather low pH decreasing rate (function of EtAc concentration and hydrothermal treatment) are essential for having the already known bimodal mesoporous silicas (BMS). On the contrary a rather high pH decreasing rate promotes the formation of the new bimodal mesoporous–macroporous silicas (BMMS) synthesized in this work, where the EtAc also plays the role of emulsion forming agent. The hydrolytic stability of the synthesized silica under aqueous conditions, at different pH values, makes these silicas good candidates for application in different areas of catalysis, especially in the enzymatic one. 相似文献