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71.
Solvothermal Syntheses,Crystal Structures,and Luminescent Properties of Two New Cadmium(II) Coordination Polymers Based on Rigid / Flexible Dicarboxylate and N,N′‐Bis(4‐pyridyl)‐1,4,5,8‐naphthalenetetracarboxydiimide 下载免费PDF全文
In order to investigate the effect of the organic ligands on the structures of coordination polymers, two new cadmium(II) coordination polymers based on the different dicarboxylate ligands, namely [Cd2(bpdc)2(DPNDI)2] · 3H2O · NMF ( 1 ) and [Cd(obb)(DPNDI)] ( 2 ) [H2bpdc = biphenyl‐4,4′‐dicarboxylate, H2obb = 4,4′‐oxybis(benzoic acid), DPNDI = N,N′‐bis(4‐pyridyl)‐1,4,5,8‐naphthalene tetracarboxydiimide, and NMF = N‐methylformamide), were synthesized under solvothermal condition and further characterized. Complex 1 shows a twofold interpenetrated pcu topology. Complex 2 possesses a two‐dimensional (2D) layer structure with –ABCD– stacking sequence. Furthermore, the luminescent properties of complexes 1 and 2 are investigated. 相似文献
72.
Highly Diastereo‐ and Enantioselective Michael Addition of Nitroalkanes to 2‐Enoyl‐Pyridine N‐Oxides Catalyzed by Scandium(III)/Copper(II) Complexes 下载免费PDF全文
Lijun Li Sheng Zhang Yanbin Hu Yanan Li Chong Li Prof. Zhenggen Zha Prof. Dr. Zhiyong Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(37):12885-12888
A C2‐symmetric Schiff‐base ligand, derived from tridentate‐Schiff‐base, was developed and successfully applied to the asymmetric Michael addition of nitroalkanes to 2‐enoyl‐pyridine N‐oxides. With this newly catalytic system, an unprecedented diastereoselectivity was obtained in the asymmetric Michael addition of nitroalkanes to 2‐enoyl‐pyridine N‐oxides. In addition, a switch in enantioselectivity was achieved by using this newly catalytic system and our previous catalyst. After a facile reduction, the optically active adduct was converted to a biologically active dihydro‐2H‐pyrrol 4 a . Furthermore, a connection of two tridentate‐Schiff‐base subunits proved to be an effective strategy in ligand design. 相似文献
73.
激光雷达以其高垂直空间分辨率和高时间分辨率的优势在大气气溶胶监测中具有重要作用。在利用Fernald法反演气溶胶消光系数和光学厚度的过程中,雷达比是反演结果的主要误差源。在目前的应用中雷达比普遍都是取固定值,这就必然给雷达反演带来误差。通过对污染物以及气象数据与雷达比的逐步回归分析,建立了雷达比估算模型,从而实现雷达比的动态估算。研究表明:雷达比的变化与空气中PM2.5质量浓度、相对湿度、SO2和NO2质量浓度等具有明显相关性。相比于固定值,利用动态雷达比反演的气溶胶消光系数和光学厚度精度明显提高。 相似文献
74.
Howard MD Lu X Rinehart JJ Jay M Dziubla TD 《Langmuir : the ACS journal of surfaces and colloids》2011,27(5):1964-1971
As the physicochemical characteristics of solid lipid nanoparticles (SLNs) play a critical role in their success, it is important to understand how the materials and process used in their preparation affect these properties. In this study, two stearyl alcohol-based formulations were prepared using nanotemplate engineering technology and characterized. Both formulations were of a small particle size (<100 nm), ellipsoidal shape, and low polydispersity. (1)H NMR spectroscopy confirmed that the SLNs have the expected solid core structure and PEGylated surface. Analysis of the bulk materials indicated that a number of complex interactions are present among the SLN components, including a eutectic between stearyl alcohol and Brij 78. The decreased crystallinity resulting from these interactions may allow for enhanced drug loading. Physiological stability was identified and confirmed as a potential problem due to the low melting point of the eutectic. However, it is expected that with appropriate formulation modifications nanotemplate engineered SLNs will possess the properties necessary for a successful drug delivery system. 相似文献
75.
76.
Desalting peptides before mass spectrometry analysis is important because salts lead to adduct formation, increased chemical noise and ion suppression effect. A high concentration of salt can clog nanoelectrospray ionization (ESI) emitters. The reverse phase C18 material is commonly used to desalt peptides because of its high binding capacity. However, peptides with high hydrophilicity, such as glycopeptides, are not retained well on this material, resulting in the loss of peptide information. To improve the efficiency of glycopeptide desalting, we introduced a hydrophilic interaction chromatography (HILIC)-based material named click maltose. Four glycoproteins, horseradish peroxidase (HRP), human serum immunoglobulin G (IgG), bovine ribonuclease B (RNase B), and α-1 acid glycoprotein (AGP) were chosen as models and their glycopeptides were desalted with click maltose, AQ C18, Empore C18 and ZipTip C18. Click maltose as a HILIC material exhibited better performance than the other three C18 materials for both number of targeted glycopeptides and their corresponding intensities. In addition, accurate glycopeptide profiling was achieved with click maltose desalting regardless of peptide lengths and glycan types. 相似文献
77.
This work demonstrated the feasibility of detecting hydrocortisone in cosmetics using a novel CdSe/CdS quantum dots‐based competitive fluoroimmunoassay with magnetic core/shell Fe3O4/Au nanoparticles (MCFN) as solid carriers. Hydrocortisone antigen was labeled with the synthesized core/shell CdSe/CdS quantum dots (QDs) to form the antigen‐QDs conjugate. Meanwhile, hydrocortisone antibody was incubated with MCFN and the immobilized antibody was obtained. The immobilized antibody was then mixed sequentially with hydrocortisone and a slightly excess amount of the QDs‐labeled hydrocortisone antigen, allowing their competition for binding with the antibody immobilized on MCFN. The bound hydrocortisone and the antigen‐QDs conjugates on MCFN were removed subsequently after the mixture was applied to a magnetic force. The analyte concentration was obtained by measuring the fluorescence intensity of the unbound hydrocortisone antigen‐QDs conjugates. The proposed method was characterized by simplicity, rapidity, and high sensitivity with a wide linear working range of 0.5 to 15000 pg·mL?1 and a low detection limit of 0.5 pg·mL?1. The proposed method was successfully applied to the determination of hydrocortisone in cosmetics with satisfactory results. 相似文献
78.
Selective enrichment of glycopeptides is of great importance for protein glycosylation analysis using mass spectrometry since
the signals of glycopeptides could be severely suppressed by the coexisting non-glycosylated peptides in the protein digest.
In the present work, a strategy for N-linked glycopeptide enrichment through reversed-phase depletion coupled with hydrophilic
affinity enrichment by applying the customized matrix named Click OEG-CD is developed. Compared with single hydrophilic interaction
liquid chromatography (HILIC) mode, the strategy exhibited remarkably higher selectivity for N-linked glycopeptides. As many
as 22, 18, and eight glycopeptides were detected in the glycopeptide fraction enriched with the strategy from the digests
of human immunoglobulin G, horseradish peroxidase and bovine ribonuclease B, respectively. In addition, the strategy also
showed high glycosylation microheterogeneity coverage for the enrichment of human α1-acid glycoprotein glycopeptides. More than 170 glycopeptides covering all the glycosylation sites were detected in the enriched
fraction. The revered-phase liquid chromatography depletion coupled with HILIC enrichment strategy by using Click OEG-CD matrix
is expected to show more potential in further applications in glycosylation analysis. 相似文献
79.
80.
M. Zha C. Ferrari S. Gennari L. Zanotti C. Razetti C. Paorici 《Crystal Research and Technology》1999,34(3):311-318
It is reported for the first time the growth of urotropine (HMT) crystals by a semiopen physical vapour transport (SOPVT) technique. HMT crystals, approximately 1 cm3 in volume, are grown on a glass pedestal from solution-grown seeds. The final habit of the crystals is limited by rhomboedrical {110} faces which develop on an otherwise hemispherical shape. Preliminary X-ray diffraction investigations (rocking curves and topographs) point to a still non-homogeneous crystal structure, which very likely originates at the seed-crystal interface. However, in comparison with solution-grown samples, the best structural quality was observed in a SOPVT-grown sample. 相似文献