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991.
Wanhua Lei Dr. Guoyu Jiang Dr. Qianxiong Zhou Dr. Yuanjun Hou Prof. Baowen Zhang Prof. Xuexin Cheng Prof. Xuesong Wang 《Chemphyschem》2013,14(5):1003-1008
Nanoscaled coordination polymers based on biologically prevalent ions have potential applications in drug delivery and biomedical imaging. Herein, coordination polymer nanoparticles of anionic porphyrins, including meso‐tetra(4‐carboxyphenyl)‐porphyrin (H2TCPP4?) and meso‐tetra(4‐sulfonatophenyl)‐porphyrin (H2TPPS4?), and alkaline or alkaline earth metal cations, such as K+ and Ca2+, were constructed in aqueous solution in the presence of cucurbit[7]uril (CB7) or cucurbit[8]uril (CB8). UV/Vis absorption and fluorescence spectroscopy, dynamic light scattering (DLS), scanning electron spectroscopy (SEM), and atomic force microscopy (AFM) were applied to explore the assembly and particle formation of porphyrin anions and metal cations mediated by CBn. The particle size depends on the kinds of CBn and metal cations and their concentrations. The uptake of H2TPPS4? particles by tumor cells (A549 cells) was found to be more efficient than H2TPPS4? at 37 °C, showing the application potential of such assembled particles in biology and medicine. 相似文献
992.
A series of 5‐benzylidenerhodamine derivatives were synthesized by the cross‐aldol condensation of an aromatic aldehyde with rhodamine or rhodamine acetic acid in sodium acetate/acetic acid under microwave irradiation. The reaction was completed in 8–20 min with 63–94% yields and was environmentally benign with easy workup. 相似文献
993.
Rui Liu Tonglai Zhang Li Yang Zunning Zhou Xiaochun Hu 《Central European Journal of Chemistry》2013,11(5):774-781
The thermal decomposition of the four nitrogen-rich salts of ammonia (NH4), aminoguanidine (AG), carbohydrazide (CHZ) and 5-aminotetrazo (ATZ) based on trinitrophloroglucinol (H3TNPG) was investigated using the differential scanning calorimetry (DSC), thermogravity (TG), and dynamic vacuum stability test (DVST). DSC and TG methods research the complete decomposition, while DVST method researches the very early reaction stage. The peak temperatures of DSC curves are consistent with the temperatures of maximum mass loss rates of TG curves. The apparent activation energies of these H3TNPG-based salts obtained by DSC and DVST have the same regularity, i.e., (ATZ)(H2TNPG)·2H2O < (CHZ)(HTNPG)·0.5H2O < NH4(H2TNPG) < (AG)(H2TNPG). The thermal stability order is (ATZ)(H2TNPG)·2H2O < (CHZ)(HTNPG)·0.5H2O < (AG)(H2TNPG) < NH4(H2TNPG), which was evaluated by DVST according to the evolved gas amount of thermal decomposition. DVST can monitor the real-time temperature and pressure changes caused by thermal decomposition, dehydration, phase transition and secondary reaction, and also evaluate the thermal stability and kinetics. 相似文献
994.
A novel method is suggested to analytically solve a nonlinear Poisson–Boltzmann (NLPB) equation. The method consists chiefly of reducing the NLPB equation to linear PB equation in several segments by approximating a free term of the NLPB equation by piecewise linear functions, and then, solving analytically the linear PB equation in each segment. Superiority of the method is illustrated by applying the method to solve the NLPB equation describing a colloid sphere immersed in an arbitrary valence and mixed electrolyte solution; extensive test indicates that the resulting analytical expressions for both the electrical potential distribution Ψ (r) and surface charge density/surface potential relationship (σ/Ψ 0) are characterized with two properties that mathematical structures are much simpler than those previously reported and application scope can be arbitrarily wide by adjusting the linear interpolation range. Finally, it is noted that the method is “universal” in that its applications are not limited to the NLPB equation. 相似文献
995.
我们用精密自动绝热量热计测定了几种不同吸附水含量的水/硅胶吸附体系在200~320 K温度范围内的热容. 结果表明, 当吸附水含量使表面复盖度(θ)大于1时, 在相应的C_p~T曲线上会出现吸附水的相变峰. 这说明吸附在硅胶表面上的水分子已经形成了聚集态; 而当θ<1时, 由于尚未形成聚集态水, 故没有相变过程出现, 其C_p~T曲线呈光滑状. 这些现象与H_2O/γ-Al_2O_3吸附体系是一致的. 又由于硅胶表面对水分子的吸附力较γ-Al_2O_3的要小, 故在同样的吸附量的C_p~T曲线上, 水/硅胶的峰要比H_2O/γ-Al_2O_3的尖锐, 且蜂温增高的速度要快. 这些都表明, 吸附在硅胶表面上的二维表相水会随吸附量的增加而以较快的趋势接近于体相水. 此外, 由不同含水量的C_p~T曲线外推, 求出了不含吸附水的硅胶在200~300 K范围内的热容. 相似文献
996.
本文用硝酸盐水溶液等浸渍法制备了一系列Cr-Ag/γ-Al2O3双金属及单金属的 物催化剂,测定了CO氧化转化率。用BET,XRD,TPR,TPD-MS技术研究了助剂Ag对Cr/γ-Al2O3催化剂CO氧化反应的作用。 相似文献
997.
用流动反应法和TPSRMS等技术研究了CO在Pd/γAl2O3和含有ZrO2的催化剂上的吸脱附行为、表面反应及催化氧化活性,同时用XRD技术测定了催化剂的物相结构。结果表明,在Pd/γAl2O3催化剂中用浸渍法添加ZrO2或掺杂超细ZrO2后,催化剂的氧化活性均有明显提高;COTPSR的实验结果表明,CO在氧化态Pd催化剂上程序升温脱附过程中主要与表面氧发生氧化反应,而在还原态Pd催化剂上发生歧化反应,并发现CO2的脱附量及脱附峰温次序与对CO的氧化活性有一致的对应关系。 相似文献
998.
液相色谱-化学发光检测法的最新进展 总被引:2,自引:0,他引:2
评述了近年来液相色谱-化学发光检测法的最新进展,参考文献从1992年到1995年。内容涉及各类化学发光反应同液相色谱体系的耦合方式,仪器设计,多种无机、有机、生物大分子、生物活性物质及药物的分析方法及其在环境、生物医学科学和生命科学、临床化学及药物化学中的应用和发展方向。 相似文献
1000.
The direct electron transfer reactions between tyrosinase and silver electrode were investigated by using cyclic voltammetry and potential-step chronoamperometry as well as current-step chronopotentiometry techniques. The kinetics of these reactions is quasi-reversible with two electron transfer reactions and 0.030 s(-1) apparent electrode reaction rate constant. The results demonstrate that neither electrode surface modification nor the inclusion of mediators is necessary to study the electron transfer reactions of tyrosinase at silver electrodes. Moreover, both the anodic and the cathodic currents are linear relationship with the tyrosinase concentration in the range of 1 x 10(-9) approximately 5 x 10(-8)moll(-1). It is possible to be used as a method of analyzing tyrosinase concentration. 相似文献