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251.
Nickel plating graphite nanosheets (Ni/GNs) were prepared by electroless plating method using graphite nanosheets (GNs). Then a novel polymer magnetic composites based on acrylate pressure-sensitive adhesive (acrylate PSA) filled with Ni/GNs were fabricated by solution blend method. The Ni/GNs and acrylate PSA/Ni/GNs composites were characterized by scanning electron microscope (SEM)/energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscope (TEM). All results showed that relatively uniform and compact Ni layer is successfully coated onto GNs under the given conditions, furthermore, Ni/GNs are homogeneously dispersed in acrylate PSA. The VSM results showed that the saturation magnetization of acrylate PSA/Ni/GNs composites increases with an increasing content of Ni/GNs while the coercivity decreases with an increasing content of Ni/GNs. When the content of GNs is 20 wt%, acrylate PSA/Ni/GNs composites exhibites good mechanical properties. 相似文献
252.
The unison of vegetable oil‐based hyperbranched polymers with nanotechnology can unhook myriad of avant‐garde applications of such materials. Thus Mesua ferrea L. seed oil‐based hyperbranched polyurethane (HBPU)/clay nanocomposites and their performance, with special reference to adhesive strength, are reported for the first time. The nanocomposites of the hyperbranched polyurethane with organically modified nanoclay were obtained by ex situ solution technique and cured by bisphenol‐A‐based epoxy with poly(amido amine) hardener system. The partially exfoliated and well‐distributed structure of nanoclay was confirmed by XRD, SEM, and TEM studies. FTIR spectra indicate the presence of H‐bonding between nanoclay and the polymer matrix. Two times improvement in the adhesive strength and scratch hardness, 10 MPa increments in the tensile strength and 112°C more thermo‐stability have been observed without much affecting the impact resistance, bending, and elongation at break of the nanocomposites compared to the pristine epoxy modified HBPU system. Thus, the resulted nanocomposites are promising materials for different advanced applications including adhesive. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
253.
Francesca Isella Elena Canellas Osvaldo Bosetti Cristina Nerin 《Journal of mass spectrometry : JMS》2013,48(4):430-437
Polyurethane adhesives are commonly used to laminate multilayer packaging materials for food. Since these materials are in direct contact with the food, compounds could migrate from adhesive into it. For this reason, it is important to identify all the potential migrants and verify their migration. Ultra‐high performance liquid chromatography–quadrupole time‐of‐flight–mass spectrometry analyses and ChemSpider database are used to identify the potential migrants from polyurethane adhesives, and these techniques were demonstrated to be very powerful and useful tools for this purpose. Migration tests were carried out using Tenax® as food simulant. Nine out of fifteen non‐volatile compounds, identified in the cured adhesives, migrated. Most of them were identified as cyclic compounds, adipic based, which is the most commonly used monomer to make the polyester/polyol resins for polyurethane bi‐component adhesives. In this work, the use of EvOH layer in several multilayer materials to minimize or avoid migration was evaluated too. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
254.
255.
Al^+注入316奥氏体不锈钢表面改性的研究 总被引:3,自引:1,他引:3
利用60kev的Al+以4×10 ̄(17)ions/cm ̄2的剂量对316奥氏体不锈钢进行了离子注入,并对注入前后之试样的显微硬度、摩擦磨损性能和电化学腐蚀性能进行了试验研究,还对Al”注入表面改性的机理作了探讨。结果发现,Al ̄+注入对316奥氏体不锈钢表面改性的效果很好,可以使其显微硬度提高43.7%,摩擦系数降低约50%,耐磨性能也有明显提高,同时还能使这种材料的腐蚀电流密度和腐蚀速率分别降低3个数量级和9个数量级。微观分析表明,注入的Al ̄+主要以替代方式存在于奥氏体结构中,改性层内大量替代式缺陷和空位型缺陷的存在造成了较大的晶格畸变,从而增强了固溶强化的效果。另外,由于铝和氧的亲和力很强,不仅容易在不锈钢表面形成氧化膜,而且还有助于磨损过程中氧化膜的形成与修复,因此,Al ̄+的注入能使316奥氏体不锈钢由粘着磨损转变为以氧化磨损为主的磨损机制。 相似文献
256.
Vibration based non-destructive evaluation shows promise for damage detection in metal-to-metal adhesive joints. This research
investigates an experimental technique to diagnose damage in single-lap adhesive joints subject to cyclical tensile loading.
Vibration analysis reveals that damage can be correlated with changes in identified modal damping ratios. Constant amplitude
forcing functions are employed to eliminate amplitude-dependent nonlinearities in the dynamic response profiles. Damping estimates
obtained from time-domain analyses correlate well with damage magnitudes. Finite element modal analysis of the lap joints
supports the experimental results. 相似文献
257.
258.
氰基丙烯酸酯20世纪70年代被引入法庭科学领域,成为显现非渗透性和半渗透性客体上潜在手印的高效方法。通过介绍氰基丙烯酸酯胶黏剂的发现与应用历史、聚合机理与手印显现原理、显出手印的增强方法,丰富了化学教育中关于聚合物、有机染料、荧光现象等方面的教学内容。 相似文献
259.
通过柠檬酸、1,8-辛二醇和多巴胺的一步熔融缩聚反应,以高碘酸钠(NaIO4)作为氧化交联剂,得到含有多巴胺的组织胶黏剂。探索了制备胶黏剂的最佳反应时间和多巴胺的最佳添加量,并利用凝胶渗透色谱(GPC)、红外光谱(FT-IR)、核磁共振氢谱(1 H-NMR)、紫外-可见分光光度法(UV-Vis)和黏结强度测试对胶黏剂的结构和性能进行了表征。结果表明:当反应时间为105min,柠檬酸、1,8-辛二醇和多巴胺的投料的物质的量之比为1.1∶1.0∶0.5时,可以得到黏结强度为99.3kPa的组织胶黏剂,达到商品α-氰基丙烯酸酯医用胶强度的40%。 相似文献
260.
Pyromellitic dimethacrylate (PMDM), a dental adhesive functional monomer has been investigated by FTIR and two-dimensional infrared spectroscopy (2D-IR) methods. With the comparison of the curing processes among three samples (Base-Resin, PMDM and monomethacrylate monomer 4-methacryloxyethyl trimellitic anhydride (4-META)), better properties and faster curing of newly used PMDM has been found. Assignments of Base-Resin, PMDM and 4-META in the mid-infrared (MIR) and near-infrared (NIR) regions are ascertained detailedly. According to the high resolution of 2D-NIR maps, assignments of the dental adhesive functional monomers are further validated and the mechanism of the curing process has been accurately concluded as well; similar 2D-NIR spectra of all three samples show the same transformation process from the double-bonds to the single-bonds during visible-light curing. 相似文献