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151.
Bibhesh?K.?SinghEmail author Parashuram?Mishra Bhagwan?S.?Garg 《Transition Metal Chemistry》2007,32(8):1110-1116
Complexes of CrIII, MnII, ZnII & CdII with the polydentate carboxamide ligandN′, N′′-bis(3-carboxy-1-oxoprop-2-enyl) 2-Amino-N-arylbenzamidine (H2L) have been synthesized and characterized by elemental analyses, spectroscopic studies (Vibrational, electronic, ESR and
1H-NMR), magnetic susceptibility measurements, thermal studies and powder diffraction studies. The vibrational spectral data
are in agreement with coordination of amide and carboxylate oxygen of the ligands with the metal ions. The electronic spectra
indicates octahedral or tetrahedral geometry around the metal ions, has been supported by magnetic susceptibility measurements.
The results of electron spin resonance & 1H-NMR spectra have supported the results of other spectral techniques. Kinetic and thermodynamic parameters were computed
from the thermal data using Coats and Redfern method, which confirm first order kinetics. Powder diffraction determines the
cell parameters of the complexes. 相似文献
152.
Photoinduced electron transfer in a hexaphenylbenzene-based self-assembled porphyrin-fullerene triad
Terazono Y Kodis G Liddell PA Garg V Gervaldo M Moore TA Moore AL Gust D 《Photochemistry and photobiology》2007,83(2):464-469
A hexaphenylbenzene-based zinc porphyrin dyad forms a 1:1 complex with a fullerene bearing two pyridyl groups via coordination of the pyridyl nitrogens with the zinc atoms. The fullerene is symmetrically located between the two zinc porphyrins. The binding constant for the complex is 7.3 x 10(4) M(-1) in 1,2-difluorobenzene. Photoinduced electron transfer from a porphyrin first excited singlet state to the fullerene occurs with a time constant of 3 ps, and the resulting charge-separated state has a lifetime of 230 ps. This self-assembled construct should form a basis for the construction of more elaborate model photosynthetic antenna-reaction center systems. 相似文献
153.
Gamma-ray induced decomposition of binary mixtures of potassium nitrate with 90, 70, 50, 30 and 10 mol% SiO2, Al2O3, MnO2, V2O5, La2O3, CeO2, Sm2O3, Eu2O3, Gd2O3 and Dy2O3 has been studied at different doses up to 500 kGy. Radiolytic decomposition of the nitrate is affected by the concentration
of the oxide in the binary mixture as well as by the absorbed dose. The enhancement is up to 103 times at 90 mol% of the additive.G(NO2
−) values calculated on the basis of electron fraction of the nitrate decrease with the increasing concentration of the nitrate.
A comparison ofG(NO2
−) for 90 mol% oxides shows decreasing trend as Gd2O3>Sm2O3≈Dy2O3> Eu2O3>CeO2>Al2O3>V2O5>SiO2>MnO2. ESR and TL measurements suggest the formation of radical species which interact with the radical species of nitrate causing
enhanced decomposition by energy transfer mechanism. 相似文献
154.
AnupaK. Patnaik N. SubbaRao Pradeep Kumar AshwaniK. Sharma BhagwanS. Garg KailashC. Gupta 《Helvetica chimica acta》2000,83(2):322-327
A simple protocol for the preparation of high‐loading supports, suitable for large‐scale synthesis of oligonucleotides, has been developed. The method involves the use of inexpensive reagents and is amenable to large‐scale preparation of supports. The derivatized supports were successfully employed in an automated DNA synthesizer without any difficulty. The quality of the synthesized oligonucleotides was found to be comparable to that of the corresponding oligomers prepared with commercially available standard supports. 相似文献
155.
A. N. Garg A. Kumar A. G. C. Nair A. V. R. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(1):53-58
Brahmi (Bacopa monnieri) leaves, known as nervine tonic in Ayurveda, and its aqueous (BA), methanolic (BM) and aqueous–methanolic (BAM) extracts
were analyzed for 7 minor (Al, Fe, Na, K, Ca, P, Cl) and 18 trace (As, Au, Ba, Br, Co, Cr, Cu, Hf, Hg, La, Mn, Rb, Se, Sm,
Sr, Th, V, Zn) elements by INAA. BAM extract showed maximum contents of Na, K, Cl and significant amounts of Mn, Co, Zn. It
was also found as effective scavenger of DPPH radicals with 33.5% total phenolic content, highest γ-ray radioprotective effect
and higher anti lipid peroxidation activity. 相似文献
156.
Avik Mazumder Hemendra K. Gupta Prabhat Garg Rajeev Jain Devendra K. Dubey 《Journal of chromatography. A》2009,1216(27):5228-5234
This paper details an on-flow liquid chromatography–ultraviolet–nuclear magnetic resonance (LC–UV–NMR) method for the retrospective detection and identification of alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs), the markers of the toxic nerve agents for verification of the Chemical Weapons Convention (CWC). Initially, the LC–UV–NMR parameters were optimized for benzyl derivatives of the APAs and AAPAs. The optimized parameters include stationary phase C18, mobile phase methanol:water 78:22 (v/v), UV detection at 268 nm and 1H NMR acquisition conditions. The protocol described herein allowed the detection of analytes through acquisition of high quality NMR spectra from the aqueous solution of the APAs and AAPAs with high concentrations of interfering background chemicals which have been removed by preceding sample preparation. The reported standard deviation for the quantification is related to the UV detector which showed relative standard deviations (RSDs) for quantification within ±1.1%, while lower limit of detection upto 16 μg (in μg absolute) for the NMR detector. Finally the developed LC–UV–NMR method was applied to identify the APAs and AAPAs in real water samples, consequent to solid phase extraction and derivatization. The method is fast (total experiment time ∼2 h), sensitive, rugged and efficient. 相似文献
157.
Fleroxacin is a third generation fluoroquinolone with broad spectrum antibacterial activity. In this work an LC-DAD method
for the analysis of fleroxacin was developed and validated using UV detection at 286 nm. The method was validated for linearity,
precision, robustness, LOD, LOQ, specificity and accuracy at concentrations of 0.2–20.0 μg mL−1 and r
2 = 1. The LOD and LOQ were 0.059 and 0.197 μg, respectively, the recoveries were 99.92–102.0% and the CV was less than 2.0%.
The LC-DAD validated method provided analytical sensitivity, specificity and reproducibility suitable for quality control
analysis. 相似文献
158.
Mardilovich A Craig JA McCammon MQ Garg A Kokkoli E 《Langmuir : the ACS journal of surfaces and colloids》2006,22(7):3259-3264
The interaction of the alpha5beta1 integrin with its ligand, fibronectin, supports numerous adhesive functions and has an important role in health and disease. In recent years, there has been a considerable effort in designing fibronectin-mimetic peptides to target the integrin. However, to date, the therapeutic use of these peptides has been limited, as they cannot accurately mimic fibronectin's binding affinity for alpha5beta1. A peptide-amphiphile (PR_b) was synthesized with a peptide headgroup composed of four building blocks: a spacer; RGDSP, the primary recognition site for alpha5beta1; PHSRN, the synergy binding site; and a linker. The linker was designed to mimic two important criteria: the distance and the hydrophobicity/hydrophilicity between PHSRN and RGD in fibronectin. Human umbilical vein endothelial cells were seeded on different substrates and evaluated in terms of adhesion, spreading, specificity, cytoskeleton organization, focal adhesions, and secretion of extracellular fibronectin. This peptide was shown to perform comparably to fibronectin, indicating that a biomimetic approach can result in the design of novel peptides with therapeutic potential for biomaterial functionalization. 相似文献
159.
The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations. 相似文献
160.
V. Vijayaraghavan A. Garg C. H. Wong K. Tai 《Applied Physics A: Materials Science & Processing》2014,116(3):1099-1107
Computational modeling tools such as molecular dynamics (MD), ab initio, finite element modeling or continuum mechanics models have been extensively applied to study the properties of carbon nanotubes (CNTs) based on given input variables such as temperature, geometry and defects. Artificial intelligence techniques can be used to further complement the application of numerical methods in characterizing the properties of CNTs. In this paper, we have introduced the application of multi-gene genetic programming (MGGP) and support vector regression to formulate the mathematical relationship between the compressive strength of CNTs and input variables such as temperature and diameter. The predictions of compressive strength of CNTs made by these models are compared to those generated using MD simulations. The results indicate that MGGP method can be deployed as a powerful method for predicting the compressive strength of the carbon nanotubes. 相似文献