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Complex and elegant protein patterns in rosette, scallop, Chinese arrow and dendrite shapes at macroscopic length scales were prepared using salt-induced molecular self-assembly and droplet evaporation methods. The direct visual observation method using fluorescence microscopy was adopted to characterize the formation of these protein patterns in situ. Further studies from an optical interferometric profiler have shown that both rosette and scalloped protein patterns are hierarchical structures of concentric rings consisting of many prism-like columnar stacks, with each of the stack having thousands of protein molecules. Systematic experimental studies were performed to investigate the influence of salt concentration, protein concentration and evaporation rate on the morphologies of protein patterns. Upon the analysis of the representative fluorescent microscope images some theoretical explanations, based on Deegan’s theory on the “coffee ring” effect and the dynamic self-assembly mechanism, were proposed to illustrate the dynamics for the formation of different protein patterns. Two different evaporation modes have been found: edge-enhanced evaporation for low salt concentration solutions, i.e., the higher evaporation rate exists at the edge of the droplet; center-enhanced evaporation for high salt concentration solutions, in which faster evaporation occurs at the droplet center consisting of a lot of crystallized salts. 相似文献
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Four new diterpenes, cespihypotins W–Z ( 1 – 4 ), having the verticillane skeleton and characterized by an α,β‐unsaturated γ‐hydroxycyclopentanone moiety, and a new eudesmanolide‐type sesquiterpene, cespilactam A ( 5 ), containing an α,β‐unsaturated γ‐lactam residue, were isolated from the AcOEt‐soluble fraction of the Taiwanese soft coral Cespitularia hypotentaculata. The structure and relative configuration of these metabolites was elucidated through extensive interpretation of MS, COSY, HSQC, HMBC, and NOESY experiments and by comparison of their NMR data with those of related compounds. 相似文献
158.
Inas A. Abdallah Sherin F. Hammad Alaa Bedair Mohamed A. Abdelaziz Neil D. Danielson Ahmed H. Elshafeey Fotouh R. Mansour 《Biomedical chromatography : BMC》2022,36(6):e5365
Favipiravir is a potential antiviral medication that has been recently licensed for Covid-19 treatment. In this work, a gadolinium-based magnetic ionic liquid was prepared and used as an extractant in dispersive liquid–liquid microextraction (DLLME) of favipiravir in human plasma. The high enriching ability of DLLME allowed the determination of favipiravir in real samples using HPLC/UV with sufficient sensitivity. The effects of several variables on extraction efficiency were investigated, including type of extractant, amount of extractant, type of disperser and disperser volume. The maximum enrichment was attained using 50 mg of the Gd-magnetic ionic liquid (MIL) and 150 μl of tetrahydrofuran. The Gd-based MIL could form a supramolecular assembly in the presence of tetrahydrofuran, which enhanced the extraction efficiency of favipiravir. The developed method was validated according to US Food and Drug Administration bioanalytical method validation guidelines. The coefficient of determination was 0.9999, for a linear concentration range of 25 to 1.0 × 105 ng/ml. The percentage recovery (accuracy) varied from 99.83 to 104.2%, with RSD values (precision) ranging from 4.07 to 11.84%. The total extraction time was about 12 min and the HPLC analysis time was 5 min. The method was simple, selective and sensitive for the determination of favipiravir in real human plasma. 相似文献
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Amal Soufi Hind Hajjaoui Rachid Elmoubarki Mohamed Abdennouri Haad Bessbousse Noureddine Barka 《印度化学会志》2022,99(9):100658
In this work, magnesium ferrites nanoparticles (MgFe2O4 NPs) were successfully fabricated by sol-gel auto-combustion (SGAC) method and were used in heterogeneous Fenton-like degradation of tartrazine. The obtained products were characterized using XRD, FTIR, SEM and EDX. XRD studies confirmed that the synthesized MgFe2O4 NPs had a cubic spinel structure. The average crystallite size was evaluated using the Debyee Scherrer formula and found to be in the range 16.18–28.55 nm. In FTIR spectra, two primary absorption bands at 571 cm?1 and 415 cm?1 were observed. The spinel ferrites are characterized by these bands and the EDX confirms the presence of the desired elements Mg, Fe, and O. The influences of operating parameters were examined using the Box Behnken statistical design (BD), including magnesium ferrite dosage (0.04–0.12 g/L), tartrazine concentration (30–50 mg/L) and H2O2 concentration (3.53–7.06 mM). Using analysis of variance, a significant quadratic model was created. Optimum conditions were magnesium ferrite dosage of 0.092 g/L, tartrazine concentration of 30.21 mg/L and H2O2 concentration of 6.66 mM, respectively. The predicted degradation efficiency within the optimum conditions as established by the suggested model was 98.4%. Confirmatory tests were carried out and the degradation efficiency of 98.9% was observed, which was in good agreement with the model's prediction. After five recuperation and reapplications, the catalyst's degradation efficiency remains stable. These findings indicate that a heterogeneous Fenton-like process utilizing MgFe2O4 is effective in advanced wastewater treatment. 相似文献
160.
开发了标题化合物(C7H11N2)2[CdCl4]·0.5H2O (C7H11N2=4-(二甲基氨基)吡啶鎓)的制备程序,并得到良好的收率和纯度。Cd(Ⅱ)离子在略微扭曲的四面体环境中与4个氯离子配位。晶体排列显示出层状结构,有机层和无机层交替排列,平行于(001)平面,位于x=n+1/2(n∈Z)。在晶体中,有机层和无机层通过C—H…Cl、C—H…O、N—H…Cl和N—H…O氢键相互作用连接。Hirshfeld表面分析和结构的指纹图表明分子堆积受氢键和π堆积的控制。UV-Vis漫反射光谱使我们能够用Tauc外推法确定具有半导体特性的3.596 eV的直接带隙。观察到的在562 nm处具有最大值的光致发光带归属于4-(二甲基氨基)吡啶鎓阳离子中的激发π-π*态。 相似文献