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1.
PMMA/定向碳纳米管复合材料导电与导热性能的研究   总被引:15,自引:0,他引:15       下载免费PDF全文
徐化明  李聃  梁吉 《无机化学学报》2005,21(9):1353-1356
Methyl Methacrylate(MMA) has been filled in the apertures of aligned carbon nanotubes(ACNTs). Then PMMA/ACNTs composites have been synthesized by in-situ polymerization. The SEM results show that carbon nanotubes are well dispersed and directionally arranged in the composites. The electrical conductivities of the parallel direction (parallel with ACNTs) and perpendicular direction (perpendicular with ACNTs) of composites were respectively tested to be 15 S·cm-1 and 4 S·cm-1, so the composites were conductivity anisotropic. Compared with PMMA, the thermal stable temperature of composites in air was improved by 100 ℃,and the thermal conductivity of composites was 13.64 times of PMMA.  相似文献
2.
柱状结构阵列碳纳米管膜的超疏水性研究   总被引:12,自引:1,他引:11       下载免费PDF全文
浸润性是固体表面的重要性质之一 .决定固体表面的浸润性的两个主要因素中 ,化学性质是内因 ,而几何结构形貌也是不可缺少的重要因素 .通过改变固体表面的粗糙度可以改变其浸润性 [1~ 5] .通常 ,人们用水接触角的大小来衡量固体表面水的浸润性 ,水与固体表面的接触角大于 1 5  相似文献
3.
超疏水多孔阵列碳纳米管薄膜   总被引:10,自引:1,他引:9  
碳纳米管由于具有特异的力学[1] 、光学[2 ] 、电学[3,4 ] 和磁学性质[5] ,使其在锂离子电池[6 ] 和平板展示器[7] 等方面呈现出广泛的应用前景 .Ebbesen等[8] 对无序碳纳米管材料的浸润性进行了详细研究 ,发现其很容易被水润湿 .然而 ,阵列碳纳米管膜的浸润性研究尚未见报道 .固体表面的浸润性主要由表面化学组分和几何结构两方面控制 .通常 ,加大表面粗糙度可以增强其浸润性 [9~ 16 ] .近来 ,超疏水表面 (即与水的接触角大于 1 5 0°的表面 )的研究显示了广泛的应用背景[13~ 16 ] .这种表面通常可由增加表面粗糙度和降低表面能来制备[1…  相似文献
4.
阵列聚合物纳米柱膜的超疏水性研究   总被引:8,自引:2,他引:6       下载免费PDF全文
浸润性(又称润湿性,Wettability)是固体表面的一个重要特征,它主要由表面化学组成和表面的几何结构两方面控制[1~5].近年来,超疏水性固体表面由于在防雪、防污染、抗氧化以及防止电流等方面都有非常广阔的应用前景,引起了人们的极大关注[6~11].  相似文献
5.
表面修饰引发的ZnO纳米棒阵列膜的超疏水性   总被引:7,自引:0,他引:7       下载免费PDF全文
润湿性是固体表面的重要性质之一 ,它受控于固体表面自由能和表面粗糙度的大小 ,一般可用液体在固体表面接触角的大小来衡量 .由于水与超疏水表面 (水与固体表面的接触角大于 1 5 0°的表面 )的接触面积很小 ,通过水所发生的化学发应和化学键的形成受到限制 ,使这种表面具有防水、防污染和防氧化等多种功能 ,因而备受人们的关注 [1~ 6 ] .作为宽禁带半导体材料 ,Zn O以其独特的光电和催化等性质在短波激光器、气体传感器、高效催化剂、太阳能电池等方面具有广阔的应用前景 .表面润湿性的研究对于将 Zn O用于各种器件非常重要 .Pesika等 […  相似文献
6.
Synthesis of an intercalated compound of montmorillonite and 6-polyamide   总被引:6,自引:0,他引:6  
Natural montmorillonite, fractionated from bentonite produced in Yamagata, Japan, was ion-exchanged for NH 3 + –(CH2)11–COOH, NH 3 + –(CH2)5–COOH, Al3+, Cu2+, Mg2+, Co2+, Li+, K+ and H+. The mixtures of the ion-exchanged montmorillonite and -caprolactam were heated at 263°C in glass ampoules for various periods. The intercalated compounds before and after the heating were examined by X-ray powder diffraction, DSC and GPC. Although -caprolactam was not polymerized without montmorillonite, it was polymerized at 263°C in the presence of montmorillonite. The polymerization rate varied with the interlayer cations in the order of NH 3 + –(CH2)11–COOH>Al3+>NH 3 + –(CH2)5–COOH>H+>Cu2+>Mg2+>Co2+>Li+>K+. After heating at 263°C for 5 h, the mean number-average molecular weight was about 1.5×104. Although the interlayer distance of NH 3 + –(CH2)11–COOH type montmorillonite/-caprolactam compound increased from 2.85 nm to 4.90 nm by heating at temperatures above the melting point of -caprolactam, those of other compounds were not changed. After heating at 263°C, an intercalated compound of montmorillonite and 6-polyamide, whose interlayer distance was more than 10 nm, was obtained. It is concluded that montmorillonite acts as a Brönsted acid and initiates the open ring polymerization of -caprolactam and that the driving force of swelling is the polymerization energy.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986.  相似文献
7.
The formation of complexes between -cyclodextrin and 1-alkanols hasbeen studied calorimetrically at 298 K in water and in concentrated aqueoussolutions of ethanol or urea. When a complex is formed, calorimetry enables thecalculation of both the enthalpy and the association constant, from which thefree energy and the entropy of the process can be obtained. The effects ofethanol and urea on the hydration cospheres of the interacting substances havebeen investigated through the study of the binary solutions of the involvedsolutes in water and in the mixed solvents. The findings obtained are, then,related to the consequent changes in the association parameters.The forces involved in the association process are discussed in the light of the signsand values of the thermodynamic parameters obtained. The most important featurescoming out from this study are: (i) association in water is an entropy-driven process;(ii) in concentrated aqueous solutions of cosolvent, the enthalpic term contributessignificantly to the Gibbs energy, while the entropic contribution is smaller; (iii) forevery solvent medium employed, the invariance of the entropic contribution withincreasing alkyl chain length of the alkanol is an indication that the relaxation ofwater molecules from the cavity of the macrocycle mainly determines the associationprocess.  相似文献
8.
TiO2 thin film photocatalysts coated onto soda lime glass were prepared by a dip coating process using a highly viscous solvent. The source of the TiO2 was tetraisopropyl orthotitanate, and -terpineol was used as the solvent. Two types of thin film preparation procedures based on dip coating (a sol-gel system and thermal decomposition system) were used to prepare the samples. TiO2 thin films were obtained after calcination at 450°C for 1 hour. The film thickness obtained with a single dipping was proportional to the viscosity of the dip coating solutions. The obtained thin films were transparent with a thickness of 1 m. The crystal form of the obtained photocatalyst films was anatase alone. The thin films were formed with aggregated nano-sized TiO2 single crystals (7–15 nm). The photocatalytic activity of the TiO2 thin films, as evaluated by the photooxidation of NO (1 ppm) in dry air, was as high as our previous TiO2 thin films prepared by the sol-gel method.  相似文献
9.
定向多壁碳纳米管电化学储氢研究   总被引:6,自引:0,他引:6       下载免费PDF全文
利用恒流充放电、循环伏安曲线(CV)和电化学阻抗技术(EIS)等方法对定向多壁碳纳米管(AMWCNTs)储氢的电化学行为及其储氢机制进行了探讨.研究表明,定向AMWCNTs-Cu电极有较高的电化学储氢性能,其储氢容量在1500mA/g的电流密度下可以达到1162mA·h/g.定向AMWCNTs的电化学储氢能力强与其空间结构有关,而铜粉的加入有利于提高碳纳米管的电催化反应表面积和电极电化学反应活性,有利于氢在碳纳米管中扩散,从而提高了碳纳米管电极材料的储氢量.  相似文献
10.
Using a silver-enhanced, gold-secondary antibody immuno-location approach, we investigated the mechanisms for the switch from -1,4- to -1,3-glucan biosynthesis upon wounding. Antibodies against -1,4- and -1,3-glucan synthases were used to locate these synthases before and after wounding of Mung bean (Vigna radiata var Berken) hypocotyls. Within 5 min of wounding, -1,4-glucan synthases which were densely localized on plasma membranes adjacent to the secondary walls at the wound site completely disappeared, and -1,3-glucan synthases became labeled. The immuno-location of the -1,3-glucan synthases in the secondary walls was in good accordance with the region where the -1,4-glucan synthases were localized before wounding. Aniline blue was also utilized to visualize the deposition of callose upon wounding. Within 5 min of wounding, callose had accumulated in the corresponding region where the immuno-labeling of -1,3-glucan synthase was detected after wounding. The -1,3-glucan synthases were always detected from the sieve plate and plasmodesmata which are known to have constitutive synthesis of callose regardless of wounding. Secondary walls located distantly into the tissue away from the wound site were consistently labeled by the -1,4-glucan synthase antibody even after wounding. Immuno-blot analysis clearly shows that the levels of -1,4-glucan synthase subunit Ces A decreased dramatically within 30 min, whereas the -1,3-glucan synthase subunit CFL1 levels increased significantly after wounding. The intensity of labeling reached a maximum at the wound site, and gradually decreased in correspondence with the distance from the wound site. When a protease inhibitor cocktail was applied upon wounding, neither the -1,3-glucan synthase appeared nor callose was deposited during the first 5 min of wounding. On the other hand, -1,4-glucan synthase was detected at the wound site, implying that activation of -1,3-glucan synthase may rely on the degradation of the -1,4-glucan synthase. Our study may provide new insight into -glucan synthesis in higher plants.  相似文献
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