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91.
Hyodo F Murugesan R Matsumoto K Hyodo E Subramanian S Mitchell JB Krishna MC 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,190(1):105-112
A comparative study of tissue redox-status imaging using commonly used redox sensitive nitroxides has been carried out using electron paramagnetic resonance imaging (EPRI), Overhauser magnetic resonance imaging (OMRI) and conventional T(1)-weighted magnetic resonance imaging, MRI. Imaging studies using phantoms of different nitroxides at different concentration levels showed that EPRI and OMRI sensitivities were found to be linearly dependent on line width of nitroxides up to 2 mM, and the enhancement in MRI intensity was linear up to 5 mM. The sensitivity and resolution of EPRI and OMRI images depended significantly on the line width of the nitroxides whereas the MRI images were almost independent of EPR line width. Reduction of the paramagnetic 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (3CP) by ascorbic acid (AsA) to the diamagnetic by hydroxylamine was monitored from a sequence of temporal images, acquired using the three imaging modalities. The decay rates determined by all the three modalities were found to be similar. However the results suggest that T(1)-weighted MRI can monitor the redox status, in addition to providing detailed anatomical structure in a short time. Therefore, a combination of MRI with nitroxides as metabolically responsive contrast agents can be a useful technique for the in vivo imaging probing tissue redox status. 相似文献
92.
93.
G. K. Sankaran 《Mathematische Nachrichten》1994,166(1):83-94
In this paper, by considering the Cauchy Problem for the KdV hierarchy in certain weighted Sobolev spaces, the existence of rapidly decreasing solutions is established. 相似文献
94.
95.
96.
97.
Suja Haridas C.S. Deepa K Sreejarani Sankaran Sugunan 《Reaction Kinetics and Catalysis Letters》2003,79(2):373-379
Concentrated (0.2 M) aqueous solutions of HP-acids, such as H3+x+mPVIV
mVV
x-mMo12-xO40 and their analogues with an excess VO2+ cation, are oxidized by dioxygen at 343 K and atmospheric pressure through intermediate active complexes (IAC) [Hx+m-1PVIV
mVV
x-mMo12-xO40
4
-] · [VO2+]y · O2, where m + y ≥ 3. The electron transfer to the coordinated O2 molecule inside AC is the limiting stage at high m. At low m, the formation of IAC becomes the limiting stage that results in a sharp decrease in the oxidation rate.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
98.
Sundararajan K Vidya V Sankaran K Viswanathan KS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,(10):1855-1867
Trimethyl phosphate (TMP) and acetylene were codeposited in nitrogen and argon matrices and adducts of these species were identified using infrared spectroscopy. Formation of the adducts was evidenced by shifts in the vibrational frequencies of the modes involving the TMP and acetylene submolecules. The structures of these adducts, energies and the vibrational frequencies were computed at the HF/6-31G** level. Both the experimental and computational studies indicated that two types of TMP-acetylene complexes were formed; one in which the hydrogen in acetylene was bonded to the phosphoryl oxygen and another in which the bonding was at the alkoxy oxygen of the phosphate. In addition to the primary hydrogen bonded interaction at the phosphoryl oxygen, this complex, also appeared to be stablilized by a secondary and weaker interaction involving a methyl hydrogen in TMP and the pi cloud in acetylene--a case of a H...pi interaction. The computed vibrational frequencies in the adducts agreed well with the observed frequencies for the modes involving the TMP submolecule, while the agreement was relatively poor for the modes involving the acetylene submolecule. The stabilization energies of these adducts, corrected for both zero-point energies and basis set superposition errors, were approximately 3 kcal/mol for the phosphoryl complex and, approximately 1 kcal/mol for the alkoxy complex. 相似文献
99.
Sankaran Chandramouleeswaran Bhavaniamma Vijayalakshmi Satrugnan Kartihkeyan Talasila Prasada Rao Chonatumatom S. P. Iyer 《Mikrochimica acta》1998,128(1-2):75-77
A highly sensitive and selective ion-chromatographic procedure with UV detection at 227 nm was developed for the determination of trace amounts of iodide. The procedure utilizes 0.1M NaOH as eluent, which enables the determination of 1–100 g I–1 I– with a precision of ca. 6%. 1000-fold amounts of other anions such as fluoride, chloride, phosphate, sulphate, bromide, nitrite and nitrate do not interfere. The method has been applied to determine iodide in sea water samples from the Indian coast. 相似文献
100.
Dy2O3 activated at high temperature is reported as a catalyst for the liquid phase reduction of cyclohexanone. The catalytic activity of Dy2O3 activated at 300, 500 and 800°C and its mixed oxides with alumina for the reduction of cyclohexanone with 2-propanol has been reported. The data have been correlated with the electron donating properties of the catalysts which were reported from the adsorption of electron acceptors [EA] of various electron affinity on the surface of these oxides. 相似文献