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961.
Highly Active Bidirectional Electron Transfer by a Self‐Assembled Electroactive Reduced‐Graphene‐Oxide‐Hybridized Biofilm
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Prof. Yang‐Chun Yong Yang‐Yang Yu Prof. Xinhai Zhang Prof. Hao Song 《Angewandte Chemie (International ed. in English)》2014,53(17):4480-4483
Low extracellular electron transfer performance is often a bottleneck in developing high‐performance bioelectrochemical systems. Herein, we show that the self‐assembly of graphene oxide and Shewanella oneidensis MR‐1 formed an electroactive, reduced‐graphene‐oxide‐hybridized, three‐dimensional macroporous biofilm, which enabled highly efficient bidirectional electron transfers between Shewanella and electrodes owing to high biomass incorporation and enhanced direct contact‐based extracellular electron transfer. This 3D electroactive biofilm delivered a 25‐fold increase in the outward current (oxidation current, electron flux from bacteria to electrodes) and 74‐fold increase in the inward current (reduction current, electron flux from electrodes to bacteria) over that of the naturally occurring biofilms. 相似文献
962.
Nanocomposites of Tantalum‐Based Pyrochlore and Indium Hydroxide Showing High and Stable Photocatalytic Activities for Overall Water Splitting and Carbon Dioxide Reduction
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Meng‐Chun Hsieh Guan‐Chang Wu Dr. Wei‐Guang Liu Prof. William A. Goddard III Prof. Dr. Chia‐Min Yang 《Angewandte Chemie (International ed. in English)》2014,53(51):14216-14220
Nanocomposites of tantalum‐based pyrochlore nanoparticles and indium hydroxide were prepared by a hydrothermal process for UV‐driven photocatalytic reactions including overall water splitting, hydrogen production from photoreforming of methanol, and CO2 reduction with water to produce CO. The best catalyst was more than 20 times more active than sodium tantalate in overall water splitting and 3 times more active than Degussa P25 TiO2 in CO2 reduction. Moreover, the catalyst was very stable while generating stoichiometric products of H2 (or CO) and O2 throughout long‐term photocatalytic reactions. After the removal of In(OH)3, the pyrochlore nanoparticles remained highly active for H2 production from pure water and aqueous methanol solution. Both experimental studies and density functional theory calculations suggest that the pyrochlore nanoparticles catalyzed the water reduction to produce H2, whereas In(OH)3 was the major active component for water oxidation to produce O2. 相似文献
963.
Chong Zhao Dan Lei Prof. Li‐Hua Gan Dr. Zhu‐Xia Zhang Prof. Chun‐Ru Wang 《Chemphyschem》2014,15(13):2780-2784
Sc2S@C84 has recently been detected but not structurally characterized. 1 Density functional theory calculations on C84 and Sc2S@C84 show that the favored isomer of Sc2S@C84 shares the same parent cage as Sc2C2@C84, whereas Sc2S@C84:51383, which violates the isolated‐pentagon rule, is the second lowest energy isomer with the widest HOMO–LUMO gap and shows high kinetic stability. The analysis shows that Sc2S@C84:51575 is favored when the temperature exceeds 2 800 K and it can transform into the most favorable isomer Sc2S@C84:51591. Molecular orbital analysis indicates that both Sc2S and Sc2C2 formally transfer four electrons to the cage, and quantum theory of atoms in molecules analysis demonstrates that there is a covalent interaction between Sc2S and C84:51591. The IR spectra of Sc2S@C84 are provided to aid future structural identification. 相似文献
964.
Rapid analysis of aflatoxins B1, B2, and ochratoxin A in rice samples using dispersive liquid–liquid microextraction combined with HPLC
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A novel, simple, and rapid method is presented for the analysis of aflatoxin B1, aflatoxin B2, and ochratoxin A in rice samples by dispersive liquid–liquid microextraction combined with LC and fluorescence detection. After extraction of the rice samples with a mixture of acetonitrile/water/acetic acid, mycotoxins were rapidly partitioned into a small volume of organic solvent (chloroform) by dispersive liquid–liquid microextraction. The three mycotoxins were simultaneously determined by LC with fluorescence detection after precolumn derivatization for aflatoxin B1 and B2. Parameters affecting both extraction and dispersive liquid–liquid microextraction procedures, including the extraction solvent, the type and volume of extractant, the volume of dispersive solvent, the addition of salt, the pH and the extraction time, were optimized. The optimized protocol provided an enrichment factor of approximately 1.25 and with detection of limits (0.06–0.5 μg/kg) below the maximum levels imposed by current regulations for aflatoxins and ochratoxin A. The mean recovery of three mycotoxins ranged from 82.9–112%, with a RSD less than 7.9% in all cases. The method was successfully applied to measure mycotoxins in commercial rice samples collected from local supermarkets in China. 相似文献
965.
在对木聚糖来源及其结构进行分类比较的基础上,采用分子动力学模拟方法及Materials Studio 4.0软件对蔗渣木聚糖及木糖单元等进行微观模拟计算.通过原子净电荷、电子密度和Fukui函数分析等分析方法,对蔗渣木聚糖的木糖单元进行结构优化,得到了蔗渣木聚糖的木糖单元优化构型的键长、键角和电荷密度.木糖单元原子的Hirshfeld净电荷与Fukui函数分析数据表明,木糖单元的活性中心主要在C(3)上的羟基位置,且羟基氧原子易受亲电试剂的攻击,羟基氢原子易受亲核试剂的攻击.对蔗渣木聚糖单分子链及无定形结构进行模拟,得到了蔗渣木聚糖的微观结构模型,显示蔗渣木聚糖分子具有链状结构,大致呈螺旋状.获得了蔗渣木聚糖的最优化无定形结构,并通过计算得到了其最优化无定形结构的X射线衍射图谱.研究结果为系统探讨蔗渣木聚糖及其衍生物的结构与性能关系奠定了基础. 相似文献
966.
以2-氨基-4-噻唑乙酸乙酯(EATA)和氯化镉水合物为原料,在无水乙醇和乙醇-水混合物两种溶剂中分别合成了配合物[CdCl2(EATA)]n(1)和[CdCl2(EATA)2](2),并利用X-射线单晶衍射、元素分析、红外光谱和荧光光谱对它们进行了表征。配合物1和2都属于单斜晶系,分别为P21/c和Cc空间群,它们的中心金属离子Cd2+均为扭曲的六配位八面体构型。在配合物1中,相邻的2个八面体单元通过2个μ2-Cl-阴离子双桥连形成一维链结构,该一维链进一步通过N-H…Cl分子间氢键形成了三维网络结构,而配合物2则通过大量的N-H…Cl和C-H…Cl分子间氢键等弱作用组装成二维超分子结构。固态荧光光谱分析表明,配合物1和2荧光性质相似,均可归属于由配体到金属间的电荷转移(LMCT)。 相似文献
967.
含Ti的HMS介孔材料催化剂及其对丙烯环氧化催化性能的研究 总被引:1,自引:1,他引:0
分别用水热合成法和气相四氯化钛(TiCl4)接枝法制备了Ti-HMS和Ti/HMS催化剂.表征结果表明,经过气相TiCl4接枝后的样品依然保持HMS(Hexagonal Mesoporous Silica,缩写为HMS)介孔材料特征,钛(Ti)物种主要以四配位的活性位形式存在.经过甲基接枝处理的催化材料,增加了表面的疏水性.丙烯环氧化反应结果表明,SN-Ti/HMS具有更高的催化性能.在2 500 h的稳定试验中,过氧化氢异丙苯(CHP)转化率大于99.0%,环氧丙烷(PO)选择性大于96.0%.研究和优化了环氧化反应工艺条件.采用浓度为30%的CHP为原料,CHP重量空速为1.0 h-1,床层温度为100℃,反应压力为3.0 MPa. 相似文献
968.
969.
首次报道了甲醛衍生的胺缩醛和芳基硼酸在水的促进下,可以在没有催化剂的条件下高效的合成三级胺.在此基础上建立了一种利用多聚甲醛,二级胺和芳基或杂环硼酸合成三级胺的高效合成方法.此反应条件温和,操作简单,具有很好的底物适应性,目标产物的收率最高可达93%. 相似文献
970.
综述了近年来烟用香精、香料各组分化合物的定量分析方法的研究进展。面积归一化法、内标法、外标法和标准加入法等常用色谱定量分析方法主要用于烟用香精、香料中目标化合物或单个组分的测定;多标定量法、特征峰-内标定量法和多元校正法能深入剖析烟用香精复杂体系中各组分含量(引用文献48篇)。 相似文献