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41.
Sagar E. Shirsath B.G. Toksha S.M. Patange Ganesh S. Jangam 《Journal of Physics and Chemistry of Solids》2010,71(12):1669-1675
The ferrite samples of a chemical formula Ni0.5−xMnxZn0.5Fe2O4 (where x=0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) were synthesized by sol-gel auto-combustion method. The synthesized samples were annealed at 600 °C for 4 h. An analysis of X-ray diffraction patterns reveals the formation of single phase cubic spinel structure. The lattice parameter increases linearly with increase in Mn content x. An initial increase followed by a subsequent decrease in saturation magnetization with increase in Mn content is observed showing inverse trend of coercivity (Hc). Curie temperature decreases with increase in Mn content x. The initial permeability is observed to increase with increase in Mn content up to x=0.3 followed by a decrease, the maximum value being 362. Possible explanation for the observed structural, magnetic, and changes of permeability behavior with various Mn content are discussed. 相似文献
42.
ABSTRACTNanocrystalline Ni0.4Cu0.3Zn0.3Fe2O4 ferrites doped with TiO2 (0–10?wt %) were prepared by the sol-gel method. Elastic properties of synthesized samples were studied with the help of ultrasonic pulse transmission method. The elastic constants initially increase with an increase in TiO2 up to 1?wt % and then decline. LCR-Q meter was used to study the dielectric properties within 50?Hz to 5?MHz range of the frequency. The dielectric constant (?′) and dielectric loss tangents were decreased continuously with increased frequency for all the selected samples at room temperature revealing normal dielectric behavior of ferrites. Also, the AC conductivity was increased with an increase in the frequency for all the selected samples. Cole-Cole plots were obtained for all investigated samples and showed single semicircle which indicates that the electrical conduction process appears only due to grain boundaries. 相似文献
43.
In this paper, we present the spectral results of Dy3+ and Pr3+ (1.0 mol%) ions doped Bi2O3-ZnF2-B2O3-Li2O-Na2O glasses. Measurements of X-ray diffraction (XRD), differential scanning calorimetry (DSC) profiles of these rare-earth ions doped glasses have been carried out. From the DSC thermograms, glass transition (Tg), crystallization (Tc) and melting (Tm) temperatures have been evaluated. The direct and indirect optical band gaps have been calculated based on the glasses UV absorption spectra. The emission spectrum of Dy3+:glass has shown two emission transitions 4F7/2→6H15/2 (482 nm) and 4F7/2→6H13/2 (576 nm) with an excitation at 390 nm wavelength and Pr3+:glass has shown a strong emission transition 1D2→3H4 (610 nm) with an excitation at 445 nm. Upon exposure to UV radiation, Dy3+ and Pr3+ glasses have shown bright yellow and reddish colors, respectively, from their surfaces. 相似文献
44.
One‐pot Synthesis of Fully Substituted Pyrimidines Using Amidine and Ketene Dithioacetals as Synthons and Their Antimicrobial Activity
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Sagar P. Gami Haresh G. Kathrotiya Yogesh T. Naliapara 《Journal of heterocyclic chemistry》2015,52(3):751-755
A simple, convenient, and efficient one‐pot synthesis of fully substituted pyrimidines was developed by cyclocondensation of α‐oxo ketene dithioacetals with amidine in the presence of potassium carbonate in good yield. Structures of all the newly synthesized compounds were elucidated by elemental analysis and spectral analysis. All the newly synthesized compounds are tested toward different microorganisms. 相似文献
45.
We present here an efficient method for the hydroboration of aldimines (-C=N-) with pinacolborane (HBpin) using an alkali metal catalyst, potassium benzyl. The reaction was accomplished with unprecedented catalytic efficiency under mild and solvent-free conditions to afford the high yield of the corresponding N-boryl amines up to 97%. Various functionalities on aldimines were incorporated for hydroboration. The corresponding boryl amines were subjected to further hydrolysis to yield the corresponding secondary amines with good yields up to 89%. This protocol for the reaction demonstrates an atom-economic and green method with diverse imines that bears excellent functional group tolerance. Chemoselective reduction of imines was also attained, with good yields of 74–89%. We also propose the most plausible mechanism involving the formation of metal hydride as the active pre-catalyst. 相似文献
46.
A General Approach Towards Triazole‐Linked Adenosine Diphosphate Ribosylated Peptides and Proteins
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Qiang Liu Dr. Hans A. V. Kistemaker Dr. Sagar Bhogaraju Prof. Dr. Ivan Dikic Prof. Dr. Herman S. Overkleeft Prof. Dr. Gijsbert A. van der Marel Prof. Dr. Huib Ovaa Dr. Gerbrand J. van der Heden van Noort Dr. Dmitri V. Filippov 《Angewandte Chemie (International ed. in English)》2018,57(6):1659-1662
Current methods to prepare adenosine diphosphate ribosylated (ADPr) peptides are not generally applicable due to the labile nature of this post‐translational modification and its incompatibility with strong acidic conditions used in standard solid‐phase peptide synthesis. A general strategy is presented to prepare ADPr peptide analogues based on a copper‐catalyzed click reaction between an azide‐modified peptide and an alkyne‐modified ADPr counterpart. The scope of this approach was expanded to proteins by preparing two ubiquitin ADPr analogues carrying the biological relevant α‐glycosidic linkage. Biochemical validation using Legionella effector enzyme SdeA shows that clicked ubiquitin ADPr is well‐tolerated and highlights the potential of this strategy to prepare ADPr proteins. 相似文献
47.
M. Bidya Sagar K. Ravikumar S. Mehdi Y.S. Sadanandam K.T. Giju E.D. Jemmis 《Journal of chemical crystallography》1999,29(4):481-491
A series of 4(x-substituted phenyl)-1,4-dihydropyridines (x=2—CF3 (1), 2-CH3 (2), 2-OCH3 (3) and 2,4-Cl (4)) with a new substituent, the N-methylcarbamoyl (CONHCH3) group at C3 and C5 are crystallographically characterized and a comparison has been made with important conformational parameters obtained theoretically. The dihydropyridine rings are in shallow boat conformation. The phenyl substituent orientation is synperiplanar. Both the carbonyl groups are oriented anticlinal in 1, 2 and 3; but in 4, one is synclinal and the other synperiplanar with the adjacent double bond. The presence of solvent molecules in 1 (CH3OH), 2 (CH3OH), and 3 (H2O) has significantly changed the hydrogen bonding pattern. Theoretical studies at the semiempirical AM1 MO level reproduces the general features of the structures. The near planarity of the DHP ring and the orientation of the phenyl substituent make 1 and 2 encouraging targets for pharmacological, study. Crystallographic Data:1: a = 8.793(2), b = 29.962(5), c = 8.215(2) Å, = 115.28(2)°, Monoclinic, P21/c;
2: a = 8.799(2), b = 15.789(3), c = 14.074(2) Å, = 100.25(2)°, Monoclinic, P21/n; 3: a = 8.347(1), b = 8.986(1), c = 13.749(2) Å, = 97.50(1), = 94.78(1), = 101.38(1)° Triclinic, P1¯4: a = 12.928(3), b = 14.506(3), c = 9.740(2) Å, Orthorhombic, Pca21. 相似文献
48.
Ram Sagar 《Tetrahedron letters》2008,49(34):5080-5083
The synthesis of pyrimidine- and pyrazole-based acyclo-C-nucleosides as carbohybrids was optimized and developed. The synthesis of acyclic polyol-fused pyrimidines was achieved in good to excellent yield with high purity by the cyclocondensation of 2-C-formyl glycals and various amidines using K2CO3 as inorganic base in co-solvent system. In comparison, the syntheses of pyrazole-based acyclo-C-nucleosides were accomplished simply by the cyclocondensation of 2-C-formyl glycals with hydrazine hydrate at room temperature and with phenyl hydrazine at refluxing temperature in ethanol. 相似文献
49.
Noel A. Gomes Ashutosh M. Pudage Santosh S. Joshi Vikas V. Vaidya Sagar A. Parekh 《Chromatographia》2008,68(7-8):541-550
A rapid and sensitive LC–MS–MS method has been developed and validated for simultaneous analysis of abacavir (ABA) and lamivudine (LAM) in human plasma. The analytes were extracted from human plasma by SPE. Nelfinavir (NEL) and emtricitabine (EMT) were used as the internal standards for ABA and LAM, respectively. An RP18 column enabled chromatographic separation of the analytes. The method involves simple isocratic chromatography and MS detection in positive-ionization mode. Validation of the method showed response was a linear function of concentration in the ranges 100.0–7000.0 ng mL?1 for ABA and 80.0–5000.0 ng mL?1 for LAM. At the LOQ levels, inter-run and intra-run precision were within 5.80 and 3.51%, respectively, for ABA and within 4.68 and 3.16%, respectively, for LAM. Overall recovery for ABA and LAM was 59.32 and 105.18%, respectively. Total elution time was 2 min only, which enabled quantification of more than 200 plasma samples per day. This validated method was used successfully for analysis of plasma samples from a bioequivalence study. 相似文献
50.
Shipra Sagar Binitendra Naath Mongal Abhijit Dutta Paritosh Mondal William Lewis Nadis Saba 《Journal of Coordination Chemistry》2016,69(15):2364-2376
Schiff base pyridin-2-ylimino methyl naphthanol (HL) was synthesized and characterized by spectroscopic (FTIR, ESIMS, and NMR) techniques. The ligand was reacted with perchlorate salts of Mn+2, Co+2, and Ni+2. ESIMS mass spectra indicate the formation of mononuclear complex ML2 for all three complexes. CoL2 crystallizes in P21/n space group, adopting a distorted tetrahedral geometry where Co is in a N2O2 donor environment. Structure of the Co complex was optimized by DFT calculation. Solution-phase complexation between the ligand and the three metals ions: Mn+2, Co+2, and Ni+2 (pH 7.2 in tris buffer), in CH3CN–H2O was performed spectrophotometrically by UV–vis spectral study. Job’s plot from each titration suggests a 1 : 2 metal to ligand combination. The association constants for the formation of ML2 are as follows: Mn (19.80 × 103 M?1), Co (14.54 × 103 M?1) and Ni (19.04 × 103 M?1). 相似文献