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51.
Arun Kumar Varanasi Arghya Bhowmik Tanmay Sarkar Umesh V. Waghmare Mridula Dixit Bharadwaj 《Ionics》2014,20(3):315-321
With a goal to improve the performance of LiCoO2 as a cathode material in Li-ion batteries, we simulate substitution of various elements (X = Be, Mg, Al, Ga, Si and Ti) for Co using first-principles density functional theory and predict changes in its electrochemical potential. While the electrochemical potential of LiCoO2 is enhanced with substitution of Be, Mg, Al and Ga for Co, an opposite effect is predicted of Si and Ti substitution. We determine the electronic origin of these changes in electrochemical potential using (a) Bader method of topological analysis of charge density, (b) partial density of electronic states to estimate oxidation states of metal and oxygen, and charge re-distribution upon lithiation. We find that the distribution of electronic charge donated by Li is influenced by the nature of the X–O bond. A larger electron transfer to O (in XO6 octahedron) upon lithiation leads to stronger Li intercalation and thereby higher electrochemical voltage. Our findings provide a platform for a rational design of cathode materials in Li batteries with enhanced voltage. 相似文献
52.
Umesh S. Devarushi Nagaraj P. Shetti Shikandar D. Bukkitgar Suresh M. Tuwar 《Russian Journal of Electrochemistry》2018,54(10):760-768
Valacyclovir (VCH) is an antiviral drug, used in the management of viral infections such as herpes simplex and varicella-zoster in humans. It is rapidly converted to acyclovir which has antiviral activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) and Varicella-zoster virus (VZV) both in vitro and in vivo. Electrochemical behavior was studied using cyclic voltammetric method, and the analytical application was studied using differential pulse voltammetric technique. The process on the surface of electrode was found to be irreversible and diffusion controlled. The charge transfer coefficient, heterogeneous rate constant, the number of electron transferred and activation parameters were calculated. Possible free radical reaction mechanism taking place on the surface of electrode was proposed. Calibration plot constructed using differential pulse voltammetric technique and applied for quantitative analysis in pharmaceutical and human urine sample. Limit of detection (LOD) and limit of quantification (LOQ) were calculated and found to be 0.028 and 0.09 μM, respectively. The present work describes the electrochemical behavior of an antiviral drug, VCH and its determination in pharmaceutical samples. The method shows the development of a sensor for selective and sensitive determination of VCH. 相似文献
53.
Agakichiev G Baur R Breskin A Chechik R Drees A Jacob C Faschingbauer U Fischer P Fraenkel Z Fuchs C Gatti E Glässel P Günzel T de los Heros CP Hess F Irmscher D Lenkeit B Olsen LH Panebrattsev Y Pfeiffer A Ravinovich I Rehak P Schön A Schukraft J Sampietro M Shimansky S Shor A Specht HJ Steiner V Tapprogge S Tel-Zur G Tserruya I Ullrich T Wurm JP Yurevich V 《Physical review letters》1995,75(7):1272-1275
54.
Naik Anil D. Annigeri Satish M. Gangadharmath Umesh B. Revankar Vidyanand K. Mahale Vinayak B. 《Transition Metal Chemistry》2002,27(3):333-336
The binucleating ligand LH3, 2,6-diformyl-p-cresol-bis(phenylthioacetyldrazone), a Schiff base condensation product of 2,6-diformyl-p-cresol and phenylthioacetyldrazide forms complexes of the [M2ClL] type with CoII, NiII and CuII ions, which were characterized by elemental analysis, magnetic susceptibility, electronic spectra, molar conductance, i.r., n.m.r., e.p.r., t.g. and FAB mass spectral measurements. Sub-normal magnetic moments indicate the operation of antiferromagnetic coupling between the metal centres. The ligand and its copper complex show a pronounced fungistatic activity. 相似文献
55.
K. C. Rajanna M. Venkateswarlu M. Satish Kumar U. Umesh Kumar G. Venkateshwarlu P. K. Saiprakash 《国际化学动力学杂志》2013,45(2):69-80
Vilsmeier–Haack (VH) benzoylation reactions with benzaldehydes and acetophenones in acetonitrile medium obeyed second‐order reaction kinetics. Under kinetic conditions, the reactions afforded benzoyl derivatives irrespective of the nature of oxychloride (POCl3 or SOCl2) used for the preparation of VH reagent along with benzamide. The present finding is advantageous to understand the nature of reactive species as well as the mechanism of benzoylation. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 45: 69–80, 2013 相似文献
56.
Sulfation of multiple hydroxylated small organic molecules is fraught with problems of poor yield, multitude of products, and long reaction times. We have developed a rapid microwave-based method for synthesis of highly sulfated small organic molecules, which affords the per-sulfated product in moderate to excellent yields and high purity. The method is expected to be of value in the discovery of per-sulfated organic molecules as mimics of glycosaminoglycans, which are being increasingly recognized as modulators of key physiological functions. 相似文献
57.
Bhavesh Babulal Gabani Suresh P. Sulochana Vinay Kiran Umesh Todmal Ramesh Mullangi 《Biomedical chromatography : BMC》2019,33(11)
A liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the quantification of tunicamycin in rat plasma as per regulatory guideline. Chromatography of tunicamycin and the IS in the processed plasma samples was achieved on an X‐Terra phenyl column using a binary gradient (mobile phase A, acetonitrile and mobile phase B, 5 mm ammonium formate) elution at a flow rate of 0.6 ml/min. LC–MS/MS was operated under the multiple reaction monitoring mode using the electrospray ionization technique in positive ion mode and the transitions of m/z 817.18 → 596.10, 831.43 → 610.10, 845.29 → 624.10, 859.23 → 638.10 and 309.24 → 163.20 were used to quantitate homologs A–D and the IS, respectively. The total chromatographic run time was 4.5 min. The correlation coefficient (r2) was >0.99 for all homologs with accuracy 90.7–107.4% and precision 0.74–15.1%. The recovery of homologs was 78.6–90.2%. No carryover was observed and the matrix effect was minimal. Tunicamycin four homologs were found to be stable on the bench‐top for 6 h, for up to three freeze–thaw cycles, in the injector for 24 h and for 1 month at ?80 ° C. The applicability of the validated method has been demonstrated in a rat pharmacokinetic study. 相似文献
58.
59.
In this work, we have made an effort to determine whether the effective atomic numbers of H-, C-, N- and O-based composite
materials would indeed remain a constant over the energy grid of 280–1200 keV wherein incoherent scattering dominates their
interaction with photons. For this purpose, the differential incoherent scattering cross-sections of Be, C, Mg, Al, Ca and
Ti were measured for three scattering angles 60°, 80° and 100° at 279.1, 661.6 and 1115.5 keV using which an expression for
the effective atomic number was derived. The differential incoherent scattering cross-sections of the composite materials
of interest measured at these three angles in the same set-up and substituted in this expression would yield their effective
atomic number at the three energies. Results obtained in this manner for bakelite, nylon, epoxy, teflon, perspex and some
sugars, fatty acids as well as amino acids agreed to within 2% of some of the other available values. It was also observed
that for each of these samples, Z
eff was almost a constant at the three energies which unambiguously justified the conclusions drawn by other authors earlier
[Manjunathaguru and Umesh, J. Phys. B: At. Mol. Opt. Phys.
39, 3969 (2006); Manohara et al,Nucl. Instrum. Methods
B266, 3906 (2008); Manohara et al Phys. Med. Biol.
53, M377 (2008)] based on total interaction cross-sections in the energy grid of interest. 相似文献
60.
Umesh Balakrishnan Nallamuthu Ananthi Sakthivel Tamil Selvan Ravindra Pal Dr. Katsuhiko Ariga Dr. Sivan Velmathi Dr. Ajayan Vinu Dr. 《化学:亚洲杂志》2010,5(4):897-903
The immobilization of chiral oxazaborolidine complex in the well‐ordered mesochannels of SBA‐15 is demonstrated by a postsynthetic approach using 3‐aminopropyltriethoxysilane as a reactive surface modifier. The immobilized catalysts are characterized by various techniques, such as XRD, nitrogen adsorption, HRSEM, UV/Vis diffuse reflectance spectroscopy, and FTIR spectroscopy. The catalysts are used for the enantioselective reduction of aromatic prochiral ketones. The activity of the chiral oxazaborolidine complex immobilized SBA‐15 catalysts is also compared with that of the pure chiral oxazaborolidine complex, which is a homogeneous catalyst. It is found that the activity of the chiral complex immobilized SBA‐15 heterogeneous catalyst is comparable with that of the homogeneous catalyst. 相似文献