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301.
以共沉淀法合成了硅铝系载体(AS和SA),并采用改性天然高铝石为原料合成了矿物质载体(MC-1和MC-2),采用浸渍法合成了镍负载型催化剂。用常压固定床管式反应器,考察了液化石油气水蒸气重整反应活性,通过XRD、物理吸附等手段对催化剂进行了表征。结果表明,以MC-1、MC-2和SA、AS为载体的催化剂的水蒸气重整活性明显高于目前普遍使用的Ni/α-Al2O3催化剂。以SA为载体,负载5%镍的催化剂具有最好的水蒸气重整活性。在750 ℃,水碳比为2.0的条件下转化率达100%,C1选择性达94.46%。XRD分析结果表明1 300 ℃焙烧后的SA载体中存在α-Al2O3晶型和莫来石结构。硅、铝添加次序对水蒸气重整活性影响较大,硅-铝添加次序的催化剂样品的活性高于铝-硅添加次序的样品,C1选择性提高12.7%。 相似文献
302.
用中压汞灯(λ > 300 nm)照射4-苯乙烯基吡啶、2-苯乙烯基苯并噁唑和5-苯基-2-苯乙烯基噁唑三种杂芳基乙烯单体中任意两种的硫酸水溶液,得到三种交叉二聚体.用高效液相色谱跟踪研究了交叉光二聚反应,发现每组反应生成三种光二聚体,其中二种为单体自身的光二聚体,而另外一种是两种不同单体的交叉光二聚体.交叉二聚体通过柱色谱分离得到,其顺式头对尾结构经紫外、红外、氢谱、碳谱和元素分析确定.用紫外光谱和高效液相色谱跟踪研究了交叉光二聚体的稀溶液在低压汞灯(λmax=254 nm)照射下的光解反应.研究发现交叉二聚体能够彻底发生光解,首先生成原来的反式单体,所生成的反式单体容易发生异构化而生成顺式单体,最终建立起反顺异构化平衡. 相似文献
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304.
Wenling Zhang Jinlin He Zhuang Liu Peihong Ni Xiulin Zhu 《Journal of polymer science. Part A, Polymer chemistry》2010,48(5):1079-1091
A series of well‐defined amphiphilic triblock copolymers [polyethylene glycol monomethyl ether]‐block‐poly(ε‐caprolactone)‐block‐poly[2‐(dimethylamino)ethyl methacrylate] (mPEG‐b‐PCL‐b‐PDMAEMA or abbreviated as mPEG‐b‐PCL‐b‐PDMA) were prepared by a combination of ring‐opening polymerization and atom transfer radical polymerization. The chemical structures and compositions of these copolymers have been characterized by Fourier transform infrared spectroscopy, 1H NMR, and thermogravimetric analysis. The molecular weights of the triblock copolymers were obtained by calculating from 1H NMR spectra and gel permeation chromatography measurements. Subsequently, the self‐assembly behavior of these copolymers was investigated by fluorescence probe method and transmission electron microscopy, which indicated that these amphiphilic triblock copolymers possess distinct pH‐dependent critical aggregation concentrations and can self‐assemble into micelles or vesicles in PBS buffer solution, depending on the length of PDMA in the copolymer. Agarose gel retardation assays demonstrated that these cationic nanoparticles can effectively condense plasmid DNA. Cell toxicity tests indicated that these triblock copolymers displayed lower cytotoxicity than that of branched polyethylenimine with molecular weight of 25 kDa. In addition, in vitro release of Naproxen from these nanoparticles in pH buffer solutions was conducted, demonstrating that higher PCL content would result in the higher drug loading content and lower release rate. These biodegradable and biocompatible cationic copolymers have potential applications in drug and gene delivery. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1079–1091, 2010 相似文献
305.
Bin Zhang Yu Chen Xiaodong Zhuang Gang Liu Bo Yu En‐Tang Kang Jinhui Zhu Yongxi Li 《Journal of polymer science. Part A, Polymer chemistry》2010,48(12):2642-2649
A new soluble donor‐acceptor type poly(N‐vinylcarbazole)‐covalently functionalized graphene oxide (GO‐PVK) has been synthesized by reaction of DDAT (S‐1‐dodecyl‐S′‐(α,α′‐dimethyl‐α″‐aceticacid)trithiocarbonate)‐PVK with GO‐toluene‐2,4‐diisocynate. The incorporation of sufficient amount of PVK chains makes the modified GO nanosheets readily dispersible in organic solvents. The resulting material exhibits an enhanced solubility of 10 mg/mL in organic solvents. Covalent grafting of PVK onto the edge and surface of GO nanosheets did not change the carbazole absorption in the ultraviolet region, but substantially reduced the absorption intensity of GO in the visible region. The intensity of the emission band of GO‐PVK at 437 nm was a little bit quenched when compared with that of DDAT‐PVK, suggesting intramolecular quenching from PVK to GO. Such intramolecular quenching process may involve energy or electron transfer between the excited singlet states of the PVK moiety and the GO moiety. The HOMO/LUMO values and the energy bandgap of GO‐PVK experimentally estimated by the onset of the redox potentials are ?5.60, ?3.58, and 2.02 eV, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2642–2649, 2010 相似文献
306.
Bin-ping Zhuang Fa-chun Lai Li-mei Lin Ming-bao Lin Yan Qu Zhi-gao Huang 《化学物理学报(中文版)》2010,23(1):79-83
ZnO nanobelts, hollow microspheres, and urchins have been prepared on copper foil via a simply low temperature evaporation route. The microstructure, morphologies, and photolu-minescence of the ZnO nanostructures were studied with X-ray diffraction, Raman spectra, scanning electron microscopy and photoluminescence spectra. The width of the nanobelts was about 500 nm and the length was longer than 10μm. The diameter of the hollow microspheres was between 5 and 10μm. A possible growth mechanism of the nanobelts, microspheres and urchins was proposed. The photoluminescence spectrum exhibited strong deep level energy emissions and a weak near band edge emission. These ZnO nanostructures on a copper substrate have the advantages of naturally good adhesion and electrical connection between the ZnO nanostructures and the conductive substrate. 相似文献
307.
Helical mesoporous silica nanorods were prepared using cetyltrimethylamrnonium bromide and achiral alcohols as the co-structure-directing agents.They were characterized using field-emission scanning electron microscopy,transmission electron microscopy,nitrogen sorptions,and small angle X-ray diffraction.The length of the silica nanorods increases with increasing the length of the alcohols.When n-heptanol and n-octanol were used,helical mesoporous silica nanorods with lamellar mesopores on the surfaces were obtained. 相似文献
308.
酸性介质中Os(Ⅳ)对溴酸钾氧化DBC-偶氮肿的褪色反应有明显的催化作用,据此反应建立了微量娥的催化光度分析法,锇在1.0-20.0μg·L-1符合比耳定律.反应在水相中进行,灵敏度高,简便快速,用于贵金属精矿中娥的测定,结果满意. 相似文献
309.
310.
铈对纳米铁氧体粉末电磁学性质影响的研究 总被引:11,自引:1,他引:11
采用固相反应制备的Ce0 .2 5FeNiO3,FeNiO5,Fe3O4 ,Fe2 O34种纳米粉体 ,在 1~ 2 0 0 0MHz范围内进行了电磁学性质 (μ′,μ″ ,ε′,ε″)及吸波特性的比较研究。发现 4种纳米粉体的 μ′数据大小顺序为Ce0 .2 5FeNiO3>FeNiO5>Fe3O4 >Fe2 O3,μ″的变化幅度为Ce0 .2 5FeNiO3>Fe3O4 >FeNiO5>Fe2 O3。Ce0 .2 5FeNiO3的ε′和ε″的变化幅度大于其他几种纳米粉体。结果表明 ,加入稀土铈的铁氧体纳米粉体性能优于其他几种材料 相似文献