全文获取类型
收费全文 | 1746篇 |
免费 | 229篇 |
国内免费 | 39篇 |
专业分类
电工技术 | 12篇 |
综合类 | 71篇 |
化学工业 | 917篇 |
金属工艺 | 9篇 |
机械仪表 | 18篇 |
建筑科学 | 10篇 |
矿业工程 | 6篇 |
能源动力 | 17篇 |
轻工业 | 197篇 |
水利工程 | 1篇 |
石油天然气 | 32篇 |
武器工业 | 1篇 |
无线电 | 172篇 |
一般工业技术 | 480篇 |
冶金工业 | 15篇 |
原子能技术 | 22篇 |
自动化技术 | 34篇 |
出版年
2024年 | 1篇 |
2023年 | 100篇 |
2022年 | 63篇 |
2021年 | 132篇 |
2020年 | 106篇 |
2019年 | 118篇 |
2018年 | 75篇 |
2017年 | 94篇 |
2016年 | 68篇 |
2015年 | 65篇 |
2014年 | 81篇 |
2013年 | 126篇 |
2012年 | 145篇 |
2011年 | 111篇 |
2010年 | 84篇 |
2009年 | 110篇 |
2008年 | 71篇 |
2007年 | 92篇 |
2006年 | 98篇 |
2005年 | 69篇 |
2004年 | 49篇 |
2003年 | 54篇 |
2002年 | 32篇 |
2001年 | 17篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有2014条查询结果,搜索用时 23 毫秒
1.
The luminescent hydrogen-bonded organic framework (HOF) based films have become one of the most remarkable materials for optical application, thus, developing facile synthesis methods and establishing multifunctional applications for HOF-based luminescent materials are essential. Herein, a dual-emitting Eu3+-functionalized HOF hydrogel film ( 1 ) is fabricated successfully. 1 emits a blue-green long afterglow when turning off the UV lamp, and the long afterglow lifetime gets to 1.99 s. 1 performs great selectivity, high sensitivity, and low detection limit toward ofloxacin and flumequine, and the sensing toward ofloxacin and flumequine is in accord with the chroma and ratio modes. The fluorescent response mechanisms of 1 toward ofloxacin and flumequine are investigated in depth, which are further utilized to build an anticounterfeiting platform with high-level security. The film-based anticounterfeiting platform can conduct information encryption on demand inline with different fluorescent responses and can also fetch specific information by controlling the long afterglow intensity and excited light. This study not only provides a representative case of the fabrication of dual-emitting Eu3+-functionalized HOF-based hydrogel film but also opens the possibility of HOF-based film as intelligent luminescent materials with multifunctionalities. 相似文献
2.
Peter J. Jervis Carolina Amorim Teresa Pereira Jos A. Martins Paula M. T. Ferreira 《International journal of molecular sciences》2021,22(5)
Supramolecular peptide hydrogels are gaining increased attention, owing to their potential in a variety of biomedical applications. Their physical properties are similar to those of the extracellular matrix (ECM), which is key to their applications in the cell culture of specialized cells, tissue engineering, skin regeneration, and wound healing. The structure of these hydrogels usually consists of a di- or tripeptide capped on the N-terminus with a hydrophobic aromatic group, such as Fmoc or naphthalene. Although these peptide conjugates can offer advantages over other types of gelators such as cross-linked polymers, they usually possess the limitation of being particularly sensitive to proteolysis by endogenous proteases. One of the strategies reported that can overcome this barrier is to use a peptidomimetic strategy, in which natural amino acids are switched for non-proteinogenic analogues, such as D-amino acids, β-amino acids, or dehydroamino acids. Such peptides usually possess much greater resistance to enzymatic hydrolysis. Peptides containing dehydroamino acids, i.e., dehydropeptides, are particularly interesting, as the presence of the double bond also introduces a conformational restraint to the peptide backbone, resulting in (often predictable) changes to the secondary structure of the peptide. This review focuses on peptide hydrogels and related nanostructures, where α,β-didehydro-α-amino acids have been successfully incorporated into the structure of peptide hydrogelators, and the resulting properties are discussed in terms of their potential biomedical applications. Where appropriate, their properties are compared with those of the corresponding peptide hydrogelator composed of canonical amino acids. In a wider context, we consider the presence of dehydroamino acids in natural compounds and medicinally important compounds as well as their limitations, and we consider some of the synthetic strategies for obtaining dehydropeptides. Finally, we consider the future direction for this research area. 相似文献
3.
Caroline Cagnin Bruno Matheus Simões Fábio Yamashita Gizilene Maria de Carvalho Maria Victória Eiras Grossmann 《Polymer Engineering and Science》2021,61(2):388-396
This work aims to develop hydrogel films of starch and carboxymethyl cellulose (CMC) crosslinked with sodium trimetaphosphate (STMP) and to characterize some of their properties. Starch and STMP (S/T), starch and CMC (S/C), and mixed (S/T/C) films were prepared by casting. The degree of substitution, morphology, swelling degree, FTIR, mechanical properties, and sorption isotherms were studied. Reticulated samples (S/T and S/T/C) showed the same degree of substitution (0.050 ± 0.001). All films presented homogeneous morphology, but the mixed film showed greater roughness. Crosslinking increased the swelling capacity of the mixed hydrogel at pH 7, although it remained decreased concerning the S/T hydrogel. However, this property was sensitive to pH variations. The mixed film (S/T/C) showed greater mechanical resistance. The casting process was efficient to produce hydrogel films of starch/CMC crosslinked with STMP and the general results demonstrated the advantages of the mixed hydrogel. 相似文献
4.
以菠萝果肉纤维素(pineapple pulp cellulose,PPC)为原料,利用离子液体1-丁基-3-甲基咪唑氯盐(1-butyl-3-methylimidazole chloride,BmimCl)作溶剂,溶解PPC制备菠萝果肉纤维素水凝胶(pineapple pulp cellulose hydrogel,PPCH),以丙烯酸(acrylic acid,AA)为改性单体制备pH敏感性水凝胶(PPCH-AA),对其进行结构表征,并研究其功能特性;同时以水凝胶为载体吸附益生菌,研究其在模拟胃液和模拟肠液中的缓释行为。结果表明:所制备水凝胶的溶胀和药物缓释作用均具有pH敏感性,负载益生菌的PPCH和PPCH-AA在模拟胃液中的累计释放量(7 h内)分别为44.11 mg/g和16.7 mg/g,释放率分别为66.17%和25.05%;在模拟肠液中的累计释放量(7 h内)分别为59.25 mg/g和58.01 mg/g,释放率分别为88.87%和87.02%。结论:AA接枝的PPCH可以作为潜在的递送载体,用于益生菌的控释。 相似文献
5.
《International Journal of Hydrogen Energy》2022,47(37):16568-16579
In this paper, a polypyrrole-carbon nanotube hydrogel (PPy-CNT) with 3D macroporous structure was prepared by secondary growth method. This self-supporting material with good conductivity and biocompatibility can be directly used as anode in a microbial fuel cell (MFC). The prepared material had a uniform structure with rich 3D porosity and showed good water retention performance. The effect of the mass ratio of PPy and CNT in the hydrogel were also investigated to evaluate the electrical performance of MFC. The MFC with 10:1 PPy-CNT hydrogel anode could reached the maximum power density of 3660.25 mW/m3 and the minimal electrochemical reaction impedance of anode was 5.06 Ω. The effects of Congo red concentration, external resistance and suspended activated sludge on decolorazation and electricity generation were also investigated in the MFC with the best performance hydrogel. When the Congo red concentration was 50 mg/L and the external resistance was 200 Ω, the dye decolorization rate and chemical oxygen demand (COD) removal rate could reach 94.35% and 42.31% at 48h while the output voltage of MFC was 480 mV. When activated sludge was present, the decolorization rate and COD removal rate could be increased to 99.55% and 48.08% at 48 h. The above results showed that the porous hydrogel anode had broad application prospects in synchronous wastewater treatment and electricity production of MFC. 相似文献
6.
为扩展非织造布在保鲜包装材料中的应用,以具有药用价值的沙棘作为抗氧化保鲜成分原料,通过负载不同体积分数的沙棘提取物(SBT)制备罗布麻纳米纤维素/壳聚糖基水凝胶,并与聚酯非织造布复合制备复合水凝胶非织造布保鲜材料,对其阻隔性能、释放行为、抗氧化活性、抗菌性以及保鲜性能进行分析。结果表明:随着SBT体积分数的增加,复合水凝胶非织造布的阻隔性增强且抗氧化活性显著提高;在18 d的释放行为测试中,复合水凝胶非织造布在酸性条件下SBT的最大累计释放率可达67.84%,对金黄色葡萄球菌和大肠杆菌的抑菌带宽度均超过1 mm,有较好的抗菌性能;添加体积分数为30% SBT的复合水凝胶非织造布综合保鲜能力最佳,可储存鲜切苹果时间最长达9 d。 相似文献
7.
《International Journal of Hydrogen Energy》2022,47(57):23909-23918
The hydrogel electrolyte is an important part of safety and development potential in zinc-based energy storage equipment due to its inherent low mechanical strength and voltage decomposition. However, hydrogel electrolytes possess a reduced working life for zinc dendrites growth and a narrow voltage window. In this study, a hydrogel electrolyte prepares by the zwitterionic monomer [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) (MS) and sodium alginate (SA) alleviate these problems. The zwitterionic double-network hydrogel has good mechanical strength, inhibits the growth of zinc dendrites, enhances practicability, greatly increases the voltage window (0–2.4 V), and has self-healing properties to its rich functional groups. The assembled zinc-ion hybrid supercapacitors (ZHSs) have a high-power density of 172.33 W kg?1 and an energy density of 88.56 Wh·kg?1 at 0.5 A g?1. The assembled zinc-ion battery also has good electrochemical performance. Flexible ZHSs and batteries provide power to the timer stably under different bending angles. The zwitterionic double-network hydrogel can be applied to both zinc-based supercapacitors and batteries. 相似文献
8.
水凝胶在日常生产与生活中发挥着重要作用,但传统水凝胶由于缺乏刺激响应性等动态性,无法满足日益增长的生产与生活需求。因此,制备并应用具有优异自修复性、刺激响应性以及可适应性等动态性的超分子水凝胶(SHGs)备受关注。综述了SHGs的制备与应用研究进展,系统归纳了高分子类SHGs(如聚丙烯酸SHGs、聚丙烯酰胺SHGs等)和天然高分子类SHGs(如壳聚糖SHGs、透明质酸SHGs等)的合成方法,阐述了SHGs在生物医药、柔性传感、防污材料等领域中的应用情况,最后展望了SHGs存在问题及发展趋势。 相似文献
9.
Photocatalysts have attracted great research interest owing to their excellent properties and potential for simultaneously addressing challenges related to energy needs and environmental pollution. Photocatalytic particles need to be in contact with their respective media to exhibit efficient photocatalytic performances. However, it is difficult to separate nanometer-sized photocatalytic materials from reaction media later, which may lead to secondary pollution and a poor recycling performance. Hydrogel photocatalysts with a three-dimensional (3D) network structures are promising support materials for photocatalysts based on features such as high specific surface areas and adsorption capacities and good environmental compatibility. In this review, hydrogel photocatalysts are classified into two different categories depending on their elemental composition and recent progresses in the methods for preparing hydrogel photocatalysts are summarized. Moreover, current applications of hydrogel photocatalysts in energy conversion and environmental remediation are reviewed. Furthermore, a comprehensive outlook and highlight future challenges in the development of hydrogel photocatalysts are presented. 相似文献
10.
Clément Perrinet Edwin-Joffrey Courtial Arthur Colly Christophe Marquette René Fulchiron 《大分子材料与工程》2021,306(2):2000553
For manufacturing parts of very soft materials by liquid deposition modeling (e.g., to mimic living soft tissues), formulations of 3D-printable polydimethylsiloxane have been developed, with the aim of increasing the yield stress of the liquid and reducing the final mechanical modulus. In the present work, suspensions of solid-like hydrogel particles, which are easily 3D-printable, are prepared in order to generate yield stress, and the suspended phase is removed after manufacturing by taking advantage of the thermo-reversibility of the hydrogel behavior, resulting in porosity, which reduces the final rigidity. The reported approach is even more efficient than a previous approach based on emulsion formulations. 相似文献