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541.
编程绘制相贯两回转体之表面交线——相贯线 总被引:2,自引:0,他引:2
相贯线是工程制图中一个非常重要的组成部分。本文介绍了如何建立数学模型,用高级语言编程绘制相贯两回转体的表面交线相贯线画法。为工程技术人员彻底“甩掉图板”提供有效方法。 相似文献
542.
Traditional trip generation forecasting methods use unified average trip generation rates to determine trip generation volumes in various traffic zones without considering the individual characteristics of each traffic zone. Therefore, the results can have significant errors. To reduce the forecasting error produced by uniform trip generation rates for different traffic zones, the behavior of each traveler was studied instead of the characteristics of the traffic zone. This paper gives a method for calculating the trip efficiency and the effect of traffic zones combined with a destination selection model based on disaggregate theory for trip generation. Beijing data is used with the trip generation method to predict trip volumes. The results show that the disaggregate model in this paper is more accurate than the traditional method. An analysis of the factors influencing traveler behavior and destination selection shows that the attractiveness of the traffic zone strongly affects the trip generation volume. 相似文献
543.
Herein we report the direct fabrication of TiO(2) subwavelength structures with 1-dimensional TiO(2) nanorods on glass substrate through solvothermal process to form self-cleaning antireflection coatings. TiO(2) precursor solutions with different solvent constituents create TiO(2) nanorods with much different morphologies grown on glass substrates. Apiculate TiO(2) nanorods with vertical orientation are grown on the glass substrate which is solvothermally treated in the precursor solution containing ethylene glycol. This glass substrate exhibit the highest transmittance of 70-85% in the range of 520-800 nm and negligible absorption in visible light region (400-800 nm). Furthermore, the TiO(2) nanorod arrays show high hydrophobicity and photocatalytic degradation ability which offer the glass substrate self-cleaning properties for both hydrophilic and oily contaminants. 相似文献
544.
WANG Hongzhi SHI Yulei LI Zixuan ZHANG Weiguo YAO Suwei 《高等学校化学研究》2014,30(4):650-655
Co3O4/reduced graphene oxide composites were synthesized via a simple electrochemical method from graphene oxide and Co(NO3)2·6H2O as raw materials.Co3O4 nanoparticles with sizes of around 30-50 nm were distributed on the surface of graphene nanosheets confirmed by scanning electron microscopy and transmission electron microscopy.Electrochemical properties of Co3O4/graphene composite were tested by cyclic voltammetry,galvanostatic charge-discharge,and electrochemical impedance spectroscopy.The Co3O4/reduced graphene oxide composite was used as the pseudocapacitor electrode in the 2 mol/L NaOH aqueous electrolyte solution.The Co3O4/reduced graphene oxide composite electrode exhibited a specific capacitance of 357 F/g at a current density of 0.5 A/g in a three-electrode system.72% of capacitance was retained when the current density increased to 3 A/g.The Co3O4/reduced graphene oxide composite prepared electrodes show a high rate capability and excellent long-term stability.After 1000 cycles of charge and discharge,the capacitance is still maintained 87% at a current density of 1 A/g,indicating that the composite is a oromising alternative electrode material used for supercapacitors. 相似文献
545.
紫外光解CHBr_3被认为是产生有着重要意义的CH 自由基的主要途径,Lin首先用闪光光解法研究了CHBr_3+O_2体系的真空紫外光解.我们用自行设计的分子光解时间分辨富里叶红外发射谱仪(FTIR-TRS),重新研究了这一体系在193nm 的光解反应,得出了一些与前人不同的结果.我们仪器的工作原理已做过详细的描述,这里在光解室里注入了混合的约5Pa 的CHBr_3(Baker 公司试剂,未进一步纯化)和230Pa 的O_2(北京氧气厂电子级高纯氧),用35mJ 相似文献
546.
A new fluorescent hybrid porous polymer (HPP) is synthesized by an anhydrous FeCl3‐mediated oxidative coupling reaction of octa[4‐(9‐carbazolyl)phenyl]silsesquioxane (OCPS). The polymer possesses a surface area of 1741 m2 g?1 and hierarchical bimodal micropores (1.41 and 1.69 nm) and mesopores (2.65 nm). The material serves as an excellent adsorbent for CO2 and dyes with high adsorption capacity for CO2 (8.53 wt %,1.94 mmol g?1), congo red (1715 mg g?1) and rhodamine B (1501 mg g?1). In addition, the presence of peripheral cabozolyl groups with extended π‐conjugation in the crosslinked framework imparts luminescent character to the polymer and offers the detection of nitroaromatic compounds. 相似文献
547.
The development of adsorptive materials continues to be an important area of research for removal of heavy metal ions from waste water. The adsorption capacity can be modulated by both physical and chemical modification of the adsorbent. Herein, we combine the unique properties of polyhedral oligomeric silsesquioxane (POSS) and organocyclophosphazene as the building units to synthesize a hybrid porous material, abbreviated as PN‐POSS. The synthetic method follows a Heck reaction between hexa(4‐bromophenoxy)cyclotriphosphazene and octavinylsilsesquioxane (OVS). The Brunauer–Emmett–Teller (BET) analysis shows that the material possesses micro‐ and mesopores of 1.5 and 3.8 nm size and a surface area on the order of 500 m2 g?1. These attributes in combination with the donor ability of the phosphazene units qualify the material for high adsorption of Pb2+, Hg2+ and Cu2+ ions with maximal adsorption capacities on the order of 1326, 1927 and 2654 mg g?1, respectively. The adsorbent exhibits a good regeneration performance and can be effectively used for water treatment. 相似文献
548.
549.
1H NMR dilution experiment and FTIR were used to investigate the hydrogen bonded interaction in three different types of incompletely condensed silsesquioxanes (POSS-mono-ol, POSS-diol and POSS-triol). For POSS-triol, there existed a dynamic equilibrium between single molecule and hydrogen-bonded dimer, and the dimerization constants (Kdim) of POSS-triol in different solvents were determined by 1H NMR dilution experiment. In addition, based on hydroxy group which acted as hydrogen bond donors, the possibility of three POSS silanols as anion receptors to form host-guest complexes was also explored in this paper. 相似文献
550.
采用有监督主成分回归分析建立了油用花生品质评价模型,采用K-means聚类分析建立了油用花生的加工适宜性评价方法。研究结果表明,油用花生品质评价模型中包括粗脂肪含量、油酸/亚油酸比值和不饱和脂肪酸总含量三个指标,模型预测值与实测值之间的相关系数为0.70。该模型可以较好地将花生品种进行油用等级划分,筛选出的远杂9102、鲁花9号、徐花14、黑花生、海花1等品种制备的花生油具有较好的稳定性。该研究结果为准确判断未知花生品种是否适宜花生油加工提供了理论依据。 相似文献