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81.
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83.
Silvija Mara
i Jasmina Lapi Senka Djakovi Teuta Opa
ak‐Bernardi Ljubica Glava‐Obrovac Valerije Vr
ek Silvana Rai‐Mali 《应用有机金属化学》2019,33(1)
Novel O‐alkylated quinoline and N‐alkylated 4‐quinolone derivatives attached to the ferrocene moiety through 4,1‐ ( 7a–d , 8a–d and 12a–d ) and 1,4‐disubstituted ( 9a , 9b , 10a and 10b ) 1,2,3‐triazole moiety were synthesized. The observed regioselectivity of O‐ vs. N‐alkylation was explored by the use of NMR and computational techniques. Among the N‐alkylated derivatives, the quinolone‐ferrocene conjugate 9a displayed marked activities against chronic myeloid leukemia in blast crisis (K562) and Burkitt lymphoma (Raji). The 6‐chloroquinolone‐ferrocene conjugate 12c , with selective inhibitory activity on Raji cells and no cytostatic effect on normal MDCK1 cells was highlighted as the most promising anticancer organometallic complex in a group of O‐alkylated quinolines. 相似文献
84.
Zinc oxide has been used as a matrix for immobilization of acetylcholinesterase (AChE) and detection of the pesticide paraoxon. The immobilized enzyme retained its enzymatic activity up to three months when stored in phosphate buffered saline (pH 7.4) at 4 °C. An amperometric biosensor for the detection of paraoxon was designed. The biosensor detected paraoxon in the range 0.035-1.38 ppm and can be used to detect other AChE inhibiting organophosphate pesticides. 相似文献
85.
Silvana R. Oliveira José A. Gomes Neto Joaquim A. Nóbrega Bradley T. Jones 《Spectrochimica Acta Part B: Atomic Spectroscopy》2010
A method for determination of B, Ca, Cu, Fe, K, Mg, Mn, Mo, P, S and Zn in plant tissues by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) is proposed. This method is based on special features of HR-CS-AAS, such as side pixel registration, wavelength integrated absorbance, and molecular absorption bands, for determining macro- and micronutrients in foliar analysis without requiring several different strategies for sample preparation and adjustment of the analytes concentration ranges. Plant samples were analyzed and results for certified materials were in agreement at a 95% confidence level (paired t-test) with reference values. Recoveries of analytes added to plant digests varied within the 82–112% interval. Relative standard deviations (n = 12) were lower than or equal to 5.7% for all analytes in all concentration ranges. 相似文献
86.
This work presents the substituent effects on the 1H and 13C NMR chemical shifts in the cis-isomer of 3-Y-cyclohexanols (Y = Cl, Br, I, CH3, N(CH3)2 and OCH3) and 3-Y-1-methoxycyclohexanes (Y = F, Cl, Br, I, CH3, N(CH3)2 and OCH3). It was observed that the H-3 chemical shift, due to the substituent alpha-effect, increases with the increase of substituent electronegativity when Y is from the second row of the periodic table of elements, (CH3 *sigma(C3--H3a) interaction energy. This interaction energy, for the halogenated compounds, decreases with an increase in size of the halogen, and this is a possible reason for the largest measured chemical shift for H-3 of the iodo-derivatives. The beta-effect of the analyzed compounds showed that the chemical shift of hydrogens at C-2 and C-4 increases with the decrease of n(Y) --> *sigma(C2-C3) and n(Y) --> *sigma(C3-C4) interaction energies, respectively, showing a behavior similar to H-3. The alpha-effect on 13C chemical shifts correlates well with substituent electronegativity, while the beta-effect is inversely related to electronegativity in halogenated compounds. NBO analysis indicated that the substituent inductive effect is the predominant effect on 13C NMR chemical shift changes for the alpha-carbon. It was also observed that C-2 and C-4 chemical shifts for compounds with N(CH3)2, OCH3 and F are more shielded in comparison to the compounds having a halogen, most probably because of the larger interaction of the lone pair of more electronegative atoms (n(N) > n(O) > n(F)) with *sigma(C2-C3), *sigma(C3-C4) and *sigma(C3-H3a) in comparison with the same type of interaction with the lone pair of the other halogens. 相似文献
87.
Vignaduzzo SE Maggio RM Castellano PM Kaufman TS 《Analytical and bioanalytical chemistry》2006,386(7-8):2239-2244
Two new analytical methods have been developed as convenient and useful alternatives for simultaneous determination of hydrochlorothiazide
(HCT) and propranolol hydrochloride (PRO) in pharmaceutical formulations. The methods are based on the first derivative of
ratio spectra (DRS) and on partial least squares (PLS) analysis of the ultraviolet absorption spectra of the samples in the
250–350-nm region. The methods were calibrated between 8.7 and 16.0 mg L−1 for HCT and between 14.0 and 51.5 mg L−1 for PRO. An asymmetric full-factorial design and wavelength selection (277–294 nm for HCT and 297–319 for PRO) were used
for the PLS method and signal intensities at 276 and 322 nm were used in the DRS method for HCT and PRO, respectively. Performance
characteristics of the analytical methods were evaluated by use of validation samples and both methods showed to be accurate
and precise, furnishing near quantitative analyte recoveries (100.4 and 99.3% for HCT and PRO by use of PLS) and relative
standard deviations below 2%. For PLS the lower limits of quantification were 0.37 and 0.66 mg L−1 for HCT and PRO, respectively, whereas for DRS they were 1.15 and 3.05 mg L−1 for HCT and PRO, respectively. The methods were used for quantification of HCT and PRO in synthetic mixtures and in two commercial
tablet preparations containing different proportions of the analytes. The results of the drug content assay and the tablet
dissolution test were in statistical agreement (p < 0.05) with those furnished by the official procedures of the USP 29. Preparation of dissolution profiles of the combined
tablet formulations was also performed with the aid of the proposed methods. The methods are easy to apply, use relatively
simple equipment, require minimum sample pre-treatment, enable high sample throughput, and generate less solvent waste than
other procedures.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
88.
Hutchison JM Lindsay HA Dormi SS Jones GD Vicic DA McIntosh MC 《Organic letters》2006,8(17):3663-3665
[reaction: see text] The synthesis of an advanced intermediate in the synthesis of the title compound has been achieved. Key steps include an Ireland-Claisen rearrangement to install the C7 tertiary alcohol stereocenter, an SN2' reaction of an alkoxymethyl Cu reagent, and a diastereoselective Re-catalyzed allylic alcohol transposition. 相似文献
89.
Donfack JH Simo CC Ngameni B Tchana AN Kerr PG Finzi PV Vidari G Giardina S Buonocore D Ngadjui BT Moundipa PF Marzatico F 《Natural product communications》2010,5(10):1607-1612
Free radicals, in particular radical oxygen species (ROS), play an important role in the aetiology and pathogenesis of various diseases. Current research in many countries focuses on the use of local medicinal plants as a promising source of liver protective agents. This paper describes the hepatoprotective effects of the methanol extract and four isolated compounds from Ficus chlamydocarpa on CCl4-induced liver damage, as well as the possible antioxidant mechanisms involved in this protection. The DPPH test, along with the beta-Carotene-Linoleic Acid Model System and Ferric-Reducing Antioxidant Power assays, as well as the inhibition of microsomal lipid peroxidation were used to measure radical-scavenging and antioxidant activities. Pretreatment of rats with the methanol extract of F. chlamydocarpa before CCl4 administration, significantly prevented serum increase of hepatic enzyme markers, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), in a dose-dependent manner. The hepatoprotection was also associated with a significant enhancement in hepatic reduced glutathione (GSH) and a marked decrease of liver malondialdehyde (MDA). Among the four compounds 1-4, isolated from the methanol extract, alpha-amyrin acetate (1) and luteolin (4) showed a significant hepatoprotective activity, as indicated by their ability to prevent liver cell death and lactate dehydrogenase (LDH) leakage during CCl4 intoxication. 相似文献
90.
The essential oil from aerial parts (stems and leaves) of Atriplex undulata (Moq) D. Dietr. (Chenopodiaceae) has been studied for its in vitro antioxidant activity. The chemical composition of the oil obtained by hydrodistillation was determined by GC and GC-MS. The major constituents were p-acetanisole (28.1%), beta-damascenone (9.3%), beta-ionone (5.1%), viridiflorene (4.7%) and 3-oxo-alpha-ionol (2.2%). The antioxidant activity of the oil was determined by two methods: Crocin bleaching inhibition (Krel = 0.72 +/- 0.15) and scavenging of the DPPH radical (IC50 = 36.2 +/- 1.6 microg/mL). The presence of active compounds like p-acetanisole, carvone, vanillin, 4-vinylguaiacol, guaiacol, terpinen-4-ol and alpha-terpineol could explain the antioxidant activity observed for this oil. 相似文献