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91.
A novel oxazoline-functional methacrylate was prepared and employed as comonomer to produce nonaqueous dispersions of oxazoline-functional polymer particles. In nonaqueous free radical dispersion copolymerization of methylmethacrylate in the presence of oxazoline-functional methacrylate, ethyleneglycoldimethacrylate crosslinking agent, AIBN initiator, and polystyrene-block-poly(ethene-alt-propene) dispersing agent, the average polymer particle size, varying between 100 and 500 nm, was controlled by the dispersing agent contents. According to titration with HClO4 all oxazoline groups regardless of their location at particle surface or bulk, were accessible. Glass transition temperature decreased from 120 to 0°C when oxazoline functional methacrylate was increased from 0 to 95 mol %. As imaged by atomic force microscopy incorporation of the new oxazoline-functional methacrylate improved film formation. Oxazoline-functional polymer particles were easy to redisperse in a variety of other diluents. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2539–2548, 1997  相似文献   
92.
Surface-functionalized cationic poly(methylstyrene) (PMS) latex particles containing aldehyde and carboxylic acid groups were successfully achieved via an emulsion polymerization of 3(4)-methylstyrene in the presence of cetyltrimethylammonium bromide, followed by an in-situ oxidation catalyzed by copper chloride and tert-butyl hydroperoxide (t-BuOOH). Factors such as the type of metal catalyst, oxidant, and their concentration strongly affected the rate of oxidation. Step addition of t-BuOOH resulted in both a higher degree of oxidation and a more uniform distribution of particle size of the functionalized PMS as compared to the batch addition method. The effect of organic solvent was found to be insignificant, and the oxidation could still proceed in its absence. The particle sizes increased significantly during the oxidation but could be controlled by using crosslinked PMS latexes. Finally, the versatility of this oxidation process was demonstrated by oxidation of the polymer with a solid loading as high as 28%. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3585–3593, 1997  相似文献   
93.
三氧化铬超微粒的制备与表征   总被引:8,自引:0,他引:8  
我们曾首次报道了Fe_2O_3超微粒溶胶具有大的三阶光学非线性响应,其X~((3))值与商品用的掺杂CdS_(1-x)Se玻璃相近,并对其产生机制进行了初步研究.本文用微乳液法制备了经十二烷基苯磺酸钠(DBS)和硬脂酸(ST)表面修饰的Cr_2O_3超微粒,并用TEM、IR、XPS及紫外可见吸收光谱进行了表征.  相似文献   
94.
周鸿娟  刘敬兰 《分析化学》1997,25(8):919-922
以苯-乙醇为溶剂,在对煤气管道沉积物提取,分离后,采用25m*0.24mmI.D.的石英毛细管OV-101柱进行了GC,GC-MS分析,鉴定出19种有机成分,并用归一法作了定量分析,并用采用IR、点滴试验等方法对其无机物作了定性鉴定。  相似文献   
95.
A preliminary study of simulated thermal maturity has been conducted to evaluate the oil, gas and hydrocarbon generation potential of sphagnum coal in the Jinsuo brown coal basin, Yunnan Province and to understand the characteristics of the element composition and biomarkers in the course of thermal alteration. The experimental result was compared with that of xylitic coal, a kind of lithotype of soft brown coal. It is considered that sphagnum coal possesses the potential of forming economic accumulation of oil and gas. Its highest proportion of oil and hydrocarbon generation is 510 mg/g Corg. and 232.1 mg/g Corg. respectively. At an R_(ran)~° value of 2.51%, the ratio of gas generation from sphagnum coal attains to 620.5 ml/g Corg. In view of sphagnum coal being different from the conventional soft brown coal in various respects such as coal forming raw materials and enviroments as well as physico-chemical properties, it is Suggested as a special kind of source rock for coal-generated oil and gas.  相似文献   
96.
This work aims to develop a new mineral porous tubular membrane based on mineral coal fly ash. Finely ground mineral coal powder was calcinated at 700 °C for about 3 h. The elaboration of the mesoporous layer was performed by the slip casting method using a suspension made of the mixture of fly ash powder, water and PVA. The obtained membrane was submitted to a thermal treatment which consists in drying at room temperature for 24 h then a sintering at 800 °C. SEM photographs indicated that the membrane surface was homogeneous and did not present any macro defects (cracks, etc.). The average pore diameter of the active layer was 0.25 μm and the thickness was around 20 μm. The membrane permeability was 475 l/h m2 bar.This membrane was applied to the treatment of the dying effluents generated by the washing baths in the textile industry. The performances in term of permeate flux and efficiency were determined and compared to those obtained using a commercial alumina microfiltration membrane. Almost the same stabilised permeate flux was obtained (about 100 l/h m2). The quality of permeate was almost the same with the two membranes: the COD and color removal was 75% and 90%, respectively.  相似文献   
97.
The complex anthocyanin fraction of red wines poses a demanding analytical challenge. We have found that anthocyanins are characterised by extremely low optimal chromatographic velocities, and as a consequence generic HPLC methods suffer from limited resolving power. Slow on-column inter-conversion reactions, particularly between carbinol and flavylium species, are shown to occur on the same time scale as chromatographic separation, leading to increased plate heights at normal chromatographic velocities. In order to improve current routine HPLC separations, the use of small (1.7 μm) particles and high temperature liquid chromatography (HTLC) were investigated. 1.7 μm particles provide better efficiency and higher optimal linear velocities, although column lengths of ∼20 cm should be used to avoid the detrimental effects of conversion reactions. More importantly, operation at temperatures up to 50 °C increases the kinetics of inter-conversion reactions, and implies significantly improved efficiency under relatively mild analysis conditions. It is further demonstrated using relevant kinetic data that no on-column thermal degradation of these thermally labile compounds is observed at 50 °C and analysis times of <2 h.  相似文献   
98.
氧弹燃烧-离子色谱法测定煤中氯含量   总被引:5,自引:0,他引:5  
建立了氧弹燃烧-离子色谱测定煤中氯含量的方法.在加有(NH4)2CO3溶液和过量氧气的氧弹中燃烧煤样,释放的氯被(NH4)2CO3溶液吸收,过滤溶液后, 采用离子色谱外标法测定滤液中氯的浓度,最后计算出煤中氯的含量.色谱工作条件:淋洗液为1.8 mmol/L Na2CO3与1.7 mmol/L NaHCO3混合液,流速1 mL/min;再生液为40 mmol/L H2SO4,流速0.5 mL/min;进样量20 μL.色谱标准工作曲线线性相关系数0.9996;10次测定1 mg/L Cl-标准溶液的均值为1.0012 mg/L,相对标准偏差为1.34%;8个煤样加标回收率为90.7%~104.3%;测定标准物质GBW11119 及GBW11120的相对误差分别为1.75%和1.36%;对比研究显示,氧弹燃烧-离子色谱测定8个煤样(除两个煤样外)氯含量结果远高于艾士卡剂混合熔样-离子色谱测定结果,表明艾士卡剂混合熔样过程由于煤样未处于完全密闭状态导致部分氯的散失.  相似文献   
99.
以蒸馏水为溶剂,利用快捷、温和的液相还原法制备超细镍粉,将得到的超细镍粉作为填料制备了复合材料,考察了复合材料的电磁屏蔽和吸波性能.结果表明,超细镍粉质量分数为80%的树脂基复合材料在130MHz~1.5GHz测试频段范围内的电磁屏蔽性能高于45dB;而厚度为2mm的超细镍粉/石蜡复合材料在7GHz附近的反射率可达-27dB.  相似文献   
100.
《Analytical letters》2012,45(10):1883-1895
Abstract

A method to analyze the most hazardous Polyclyclic Aromatic Hydrocarbons (PAH) (acenaphtene, anthracene, benzo(a) anthracene, benzo(a)pyrene, biphenyl, coronene, chrysene, dibenzo (a,h) anthracene, phenantrene, fluoranthene, fluorene, naphtalene and pyrene), by using excitation and energy constant synchronic fluorescence has been researched in depth in this study.

Spectral studies carried out allow characteristic peaks to be obtained for the qualitative identification of 8 from 11 PAH tested. From the quantitative and interference studies, the most important analytical characteristics (linear range, detection limit and reproduciblity) for the determination of ten of these compounds have been obtained.

The method was applied to the PAH determination in two different samples: 1) air filter samples for urban pollution control and 2) air samples from a laboratory scale coal carbonization oven. Fluorene (in the first type) and benzo (a) pyrene (in the second type), were identified and quantified.  相似文献   
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