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471.
472.
为探索揉捻转速(35、45、55、60r/min)对工夫红茶风味品质及内质成分的影响,采用鸠坑群体种开展不同揉捻转速的制茶实验。通过感官分析与电子舌分析、色差分析相结合,探究不同揉捻转速对工夫红茶滋味、汤色等风味品质的影响;采用系统分析法和高效液相色谱法对茶色素和总茶黄素组分开展定量分析;利用基于超高效液相色谱-四极杆-静电场轨道阱高分辨质谱的代谢组学技术对4种揉捻转速所制得工夫红茶中非挥发性成分进行检测;并结合偏最小二乘判别分析及单因素方差分析,探究不同揉捻转速对工夫红茶内质成分的影响。结果显示,45r/min揉捻所制得的工夫红茶感官品质最佳,滋味和香气品质较优,电子舌和色差分析验证了45r/min揉捻制得的工夫红茶滋味和汤色品质较佳。不同揉捻转速制得的工夫红茶中有16种差异化合物,主要是原花青素C1、牡荆素、异牡荆素、天冬酰胺、天冬氨酸、没食子酸、苹果酸、琥珀酸和葡萄糖酸等,揉捻转速对酚酸类、有机酸类、茶黄素、茶红素和茶褐素等影响相对较大,对其他成分影响相对较小。45r/min揉捻制得的工夫红茶中茶红素、品质指数、糖类、天冬氨酸等含量较高,而有机酸类、酚酸类和...  相似文献   
473.
通过对豌豆白蛋白以及豌豆白蛋白-绿原酸复合物粒度、Zeta电位、荧光光谱、红外光谱与疏水性、溶解性、乳化特性等指标的测定,探究动态高压微射流不同处理压力对豌豆白蛋白和复合物结构与功能特性的影响,以及二元体系中绿原酸对豌豆白蛋白影响的机制和效果。结果表明,豌豆白蛋白经过动态高压微射流处理后,粒径与Zeta电位值均呈先降低后增加趋势;改性后的豌豆白蛋白微观结构、二级结构与三级结构均发生变化;剪切力等作用的小粒径豌豆白蛋白溶解性显著提高了42.37%,可达到0.84 mg/mL(P<0.05),乳化特性也得到一定增强。动态高压微射流处理加工豌豆白蛋白-绿原酸复合物体系中,绿原酸改变了豌豆白蛋白色氨酸的微环境,使白蛋白结构发生显著变化。绿原酸使豌豆白蛋白表面疏水性显著增加(P<0.05),溶解性显著降低(P<0.05),并将豌豆白蛋白乳化活性提高。本研究阐释了动态高压微射流和绿原酸对豌豆白蛋白的影响作用,为豌豆白蛋白改性提供思路,为高值化蛋白产品的开发提供一定理论基础。  相似文献   
474.
Using petrol to supply energy for a car or burning coal to heat a building generates plenty of greenhouse gas (GHG) emissions, including carbon dioxide (CO2), water vapor (H2O), methane (CH4), nitrous oxide (N2O), ozone (O3), fluorinated gases. These up-and-coming metal-organic frameworks (MOFs) are structurally endowed with rigid inorganic nodes and versatile organic linkers, which have been extensively used in the GHG-related applications to improve the lives and protect the environment. Porous MOF materials and their derivatives have been demonstrated to be competitive and promising candidates for GHG separation, storage and conversions as they shows facile preparation, large porosity, adjustable nanostructure, abundant topology, and tunable physicochemical property. Enormous progress has been made in GHG storage and separation intrinsically stemmed from the different interaction between guest molecule and host framework from MOF itself in the recent five years. Meanwhile, the use of porous MOF materials to transform GHG and the influence of external conditions on the adsorption performance of MOFs for GHG are also enclosed. In this review, it is also highlighted that the existing challenges and future directions are discussed and envisioned in the rational design, facile synthesis and comprehensive utilization of MOFs and their derivatives for practical applications.  相似文献   
475.
目的:减少酸奶凝固时间,改善酸奶质构。方法:以全脂乳粉为主要原料,通过添加不同量(0,0.50%,0.75%,1.00%,1.25%,1.50%)豌豆肽,制备豌豆肽酸奶,并测定酸奶的凝固时间、滴定酸度及质构特性。结果:酸奶的凝固时间在豌豆肽添加量≤1.25%时显著减少,当豌豆肽添加量为1%时效果最明显,凝固时间可缩短32 min。酸奶酸度在豌豆肽添加量为0.5%~1.5%时显著提高。当豌豆肽添加量≤1%时,酸奶的弹性和咀嚼度显著下降,内聚性、胶着度、回复性显著上升,硬度无显著变化,酸奶的质构得到改善。结论:在酸奶发酵基质中添加适量豌豆肽可显著缩短酸奶发酵周期,改善产品品质。  相似文献   
476.
The osteoimmunology has revealed that immune system plays an important role in maintaining bone metabolism and remodeling. As long-term physiological factor in bone, mechanical stimulation such as micro-vibration stimulation (MVS) exerts effects on regulating osteogenesis and immune response. In this study, the osteo-immunodulatory effects of bicalcium phosphate (BCP) ceramics coupled with MVS are investigated. This results find that the combination of BCP ceramics and MVS may exert synergistic effects on the polarization and functional status of macrophages through activating plasma membrance Ca2+ ATPase (PMCA) channel, reducing the intracellular calcium ion concentration, and inhibiting downstream extracellular signal-regulated kinase (ERK)1/2 signaling pathway. BCP ceramics coupled MVS could drive the macrophage polarization to wound-healing M2 phenotype to decrease the production of pro-inflammatory factors, enhance the secretion of anti-inflammatory cytokines and growth factors such as transforming growth factor (TGF)-β1 and bone morphogenetic protein (BMP)-2. Moreover, BCP and MVS-modulated macrophage secretion pattern can trigger the BMP/TGF-Smad signaling pathways to induce osteoblastic differentiation of bone marrow mesenchymal stromal cells (BM-MSCs) in vitro, and maintain cellular viability and promote the formation of collagen-rich osteoid like tissues and mature blood vessels in vivo. This study demonstrates that the introduction of mechanical stimuli like non-invasive MVS is an effective strategy to improve bone repair effects of biomaterials through endowing them with superior osteo-immunodulatory capacity.  相似文献   
477.
IrO2 as benchmark electrocatalyst for acidic oxygen evolution reaction (OER) suffers from its low activity and poor stability. Modulating the coordination environment of IrO2 by chemical doping is a methodology to suppress Ir dissolution and tailor adsorption behavior of active oxygen intermediates on interfacial Ir sites. Herein, the Re-doped IrO2 with low crystallinity is rationally designed as highly active and robust electrocatalysts for acidic OER. Theoretical calculations suggest that the similar ionic sizes of Ir and Re impart large spontaneous substitution energy and successfully incorporate Re into the IrO2 lattice. Re-doped IrO2 exhibits a much larger migration energy from IrO2 surface (0.96 eV) than other dopants (Ni, Cu, and Zn), indicating strong confinement of Re within the IrO2 lattice for suppressing Ir dissolution. The optimal catalysts (Re: 10 at%) exhibit a low overpotential of 255 mV at 10 mA cm−2 and a high stability of 170 h for acidic OER. The comprehensive mechanism investigations demonstrate that the unique structural arrangement of the Ir active sites with Re-dopant imparts high performance of catalysts by minimizing Ir dissolution, facilitating *OH adsorption and *OOH deprotonation, and lowering kinetic barrier during OER. This study provides a methodology for designing highly-performed catalysts for energy conversion.  相似文献   
478.
With the advantages of diverse structures, tunable enzymatic activity, and high stability, nanozymes are widely used in medicine, chemistry, food, environment, and other fields. As an alternative to traditional antibiotics, nanozymes attract more and more attention from the scientific researchers in recent years. Developing nanozymes-based antibacterial materials opens up a new avenue for the bacterial disinfection and sterilization. In this review, the classification of nanozymes and their antibacterial mechanisms are discussed. The surface and composition of nanozymes are critical for the antibacterial efficacy, which can be tailored to enhance both the bacterial binding and the antibacterial activity. On the one hand, the surface modification of nanozymes enables binding and targeting of bacteria that improves the antibacterial performance of nanozymes including the biochemical recognition, the surface charge, and the surface topography. On the other hand, the composition of nanozymes can be modulated to achieve enhanced antibacterial performance including the single nanozyme-mediated synergistic and multiple nanozymes-mediated cascade catalytic antibacterial applications. In addition, the current challenges and future prospects of tailoring nanozymes for antibacterial applications are discussed. This review can provide insights into the design of future nanozymes-based materials for the antibacterial treatments.  相似文献   
479.
工程教育质量和工程人才培养已成为高等教育急需解决的重要课题。分析了土木工程专业在实验教学、设计计算、实践实习、学科竞赛和创新创业活动等方面存在的问题,提出了打造土木工程专业工程实训平台的建设理念。从土木工程专业实验教学平台、"科研反哺教学"的实践教学平台、土木工程专业工程计算教学平台、新型"校企协作"实践教学平台和土木工程专业创新创业平台等方面,阐述了五个子平台的建设思路和建设方案。研究成果对西安建筑科技大学土木工程专业建设水平和人才培养质量提升起到了重要的作用。  相似文献   
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