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71.
用从头算SCF- MO法对三元硼氮环2 个系列8 个分子的电子结构进行了研究.根据计算结果,由原子的轨道布居以及σ和π电子的分布,讨论了硼原子与氮原子间的成键情况.结果表明,硼原子和氮原子上加H 有利于环的稳定,同时削弱了B—N 键而增强了B—B键和N—N 键,对B2N 系列和BN2 系列中的B原子和N 原子的净电荷的影响恰好相反.  相似文献   
72.
吕绍洁  邱发礼 《合成化学》1999,7(3):299-303
研究了在常压下,由甲酸甲酯与NH3反应生产甲酰胺的催化新工艺,比较了不同反应器、加或不加催化剂。催化剂活性组分含量、催化剂粒度大小及装量等对反应的影响,并考察了不同反应温度、NH3流量、反应时间与甲酰胺收率的关系,结果表明用催化新工艺在2g-M-10催化剂上,加20mL甲酸甲酯,NH4流量为4L/h,反应温度7℃,反应2h后,甲酰胺收率可达99%。  相似文献   
73.
利用脉冲气相色谱保留体积法测定了不同还原温度的氧化铁样品对水的吸附特性并和X光衍射结果进行了关联,同时测定了含铬氧化铁对水的吸附特性。结果表明,中温还原样品有比较均匀的表面,低温和高温还原样品的表面均有一定程度的不均匀性且符合焦姆金吸附方程。铬的加入降低了氧化铁对水的吸附热,并增加吸附中心的数量  相似文献   
74.
Rhodamine B-ethylenediamine--cyclodextrins (RhB--CDen) and rhodamine B--cyclodextrins (RhB--CD) can form inclusive complexes with many guest molecules, a reaction which can be used as a nucleic acid probe. In this paper, the most stable conformations of RhB--CDen and RhB--CD have been determined by fluorescence experiments and analyzed by molecular modeling simulation. The interaction between RhB--CDen and two guest molecules, 1-borneol and cyclohexanol, has also been investigated. The results showed that RhB--CDen has a stronger interaction with 1-borneol than with cyclohexanol. Borneol could push the three aromatic-rings of rhodamine B out of the CD cavity, while the cyclohexanol could not. The interactive sites of host and guest are also presented.  相似文献   
75.
The behavior of153Sm-EDTMP in vitro and vivo is analyzed by the size exclusion HPLC. The experimental results show that EDTMP amounts have an obvious effect on the stability in vitro and uptake of153Sm-EDTMP in the liver. HPLC analysis of urine sample indicates that153Sm-EDTMP es excreted in the original form. The behavior in vivo of153Sm-EDTMP containing 4 μg is similar to that of153Sm-EDTMP containing 50 μg EDTMP at 1 h post-injection.  相似文献   
76.
    
A novel synthesized Ag/C fibrous catalyst based on in situ thermally induced redox reaction of PVA/AgNO3 composite fibers was proposed. Utilizing the plasticization and complexation of AgNO3 solution, the melt spinning of PVA/AgNO3 composites was accomplished. Through the in situ thermally induced redox reaction on PVA/AgNO3 composite fibers combined with carbonization of PVA and reduction of Ag+, the synthesized Ag/C fibrous catalyst was prepared with nanosilver particles with average diameter of 130 nm immobilized on the loose microstructural carbon layers. The synthesized Ag/C fibrous catalyst exhibited excellent catalytic activity and reused for at least five cycles for the reduction of 4‐nitrophenol, which may hold great promise in effective and eco‐friendly waste water treatment.  相似文献   
77.
    
In this paper, the gas-sensing properties of copper oxide porous nanosheets in amorphous and highly crystalline states were comparatively investigated on the premise of almost the same specific surface area, morphology and size. Unexpectedly, the results show that amorphous copper oxide porous nanosheets have much better gas sensing properties than highly crystalline copper oxide to a serious of volatile organic compounds, and the lowest detection limit (LOD) of the amorphous copper oxide porous nanosheets to methanal is even up to 10 ppb. By contrast, the LOD of the highly crystalline copper oxide porous nanosheets to methanal is 95 ppb. Experiments prove that the oxygen vacancies contained in the amorphous copper oxide porous nanosheets play a key role in improving gas sensitivity, which greatly improve the chemical activity of the materials, especially for the adsorption of molecules containing oxygen-groups such as methanal and oxygen.  相似文献   
78.
    
Lapatinib is required as a therapy for advanced or metastatic breast cancer. However, its reactive metabolite (RM) nitroso was implicated in idiosyncratic hepatotoxicity. Density functional theory was performed to explore the metabolism of nitroso formation. Primary hydroxylation amine is a critical intermediate to produce nitroso. Three pathways from secondary alkylamine lapatinib to primary hydroxylation amine were designed and discussed. Calculation results show that it is difficult to form primary hydroxylation amine through common proposed hydrolysis nitrone with a barrier of 36.67 kcal/mol (path A), but it is smoothly formed by paths B and C with moderate determined barriers of 15.09 kcal/mol and 16.56 kcal/mol, respectively. Subsequently, we demonstrate that the mechanism of nitroso formation from primary hydroxylation amine should be a double hydrogen atom transfer rather than the previously proposed hydrolysis primary dihydroxylation amine. The barrier of the former is obviously lower than the latter. Based on metabolism results and structure analysis, several lapatinib derivatives are designed. Molecular docking of designed compounds with epidermal growth factor receptor (EGFR) shows that they share a similar binding mode with lapatinib. In particular, 2a to 2d show similar binding energy to lapatinib. This work showed metabolism details of nitroso formation from lapatinib and its structure modification, which can enrich the metabolism of amine drugs and provide guidance for drug optimization and design.  相似文献   
79.
    
Dilute alloy nanostructures have been demonstrated to possess distinct catalytic properties. Noble-metal-induced reduction is one effective synthesis strategy to construct dilute alloys and modify the catalytic performance of the host metal. Herein, we report the synthesis of ultrafine PtRu dilute alloy nanodendrites (PtRu NDs, molar ratio Ru/Pt is 1:199) by the reduction of RuIII ions induced by Pt metal. For the methanol oxidation reaction, PtRu NDs showed the highest forward peak current density (2.66 mA cm−2, 1.14 A/mgPt) and the best stability compared to those of pure-Pt nanodendrites (pure-Pt NDs), commercial PtRu/C and commercial Pt/C catalysts.  相似文献   
80.
A series of novel dinuclear platinum(II) complexes with a chiral tetradentate ligand, (1R,1′R,2R,2′R)-N1,N1′-(1,2-phenylenebis(methylene))dicyclohexane-1,2-diamine (HL), and mono-carboxylic acid derivatives as ligands have been designed, synthesized, and characterized. In vitro cytotoxicity evaluation of synthesized complexes against human HepG-2, A549, HCT-116, and MCF-7 cancer cell lines has been conducted by MTT assays. All compounds showed antitumor activity to HepG-2 and HCT-116 cell lines. Compound L2 exhibited better cytotoxicity than that of carboplatin against HepG-2 and A549 cell lines and also showed comparable activity against HCT-116 cell line.  相似文献   
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