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801.
Polyphenols have beneficial effects on several chronic diseases but assessing polyphenols intake from self-reported dietary questionnaires tends to be inaccurate and not very reliable. A promising alternative is to use urinary excretion of polyphenols as a proxy measure of intake. The best method to assess urinary excretion is to collect 24-h urine. However, since collecting 24-h urine method is expensive, time consuming and may be difficult to implement in large population-based studies, measures obtained from spot urine normalized by creatinine are commonly used. The purpose of the study was to evaluate the correlation between polyphenols dietary intake and total urinary polyphenol excretion (TPE), expressed by both 24-h volume and urinary creatinine normalization in 928 participants from the InCHIANTI study. Dietary intake data were collected using a validated food frequency questionnaire. Urinary TPE was analyzed by Folin-Ciocalteau assay. Both urinary TPE expression models were statistically correlated (r=0.580), and the partial correlation coefficient improved (pr=0.722) after adjusting for the variables that modify the urinary creatinine excretion (i.e. gender, age, BMI, physical activity and renal function). In crude models, polyphenol intake was associated with TPE corrected by 24-h volume (r=0.211; P<0.001), but not with creatinine normalization (r=0.014; P=0.692). However, urinary TPE expressed by creatinine correction was significantly correlated with dietary polyphenols after adjusting for covariates (pr=0.113; P=0.002). We conclude that urinary TPE expressed by 24-h volume is a better biomarker of polyphenol dietary intake than by urinary creatinine normalization. After covariate adjustment, both can be used for studying the relationships between polyphenol intake and health in large-scale epidemiological studies.  相似文献   
802.
The synthesis of N‐benzyl‐ and N‐cyclohexylammonium resorcinarene trifluoroacetate (TFA) and triflate (OTf) salt receptors was investigated. Solid‐state analysis by single‐crystal X‐ray diffraction revealed that the N‐alkylammonium resorcinarene salts (NARSs) with different upper substituents had different cavity sizes and different affinities for anions. Anion‐exchange experiments by mixing equimolar amounts of N‐benzylammonium resorcinarene trifluoroacetate and N‐cyclohexylammonium resorcinarene triflate, as well as N‐benzylammonium resorcinarene triflate and N‐cyclohexylammonium resorcinarene trifluoroacetate showed that the NARS with flexible benzyl groups preferred the larger OTf anion, whereas the rigid cyclohexyl groups preferred the smaller TFA anions. The anion‐exchange processes were confirmed in the solid state by single‐crystal and powder X‐ray diffraction experiments and in the gas phase by electrospray ionization mass spectrometry.  相似文献   
803.
Breynia retusa (Dennst.) Alston (also known as Cup Saucer plant) is a food plant with wide applications in traditional medicine, particularly in Ayurveda. Extracts obtained with four solvents (dichloromethane, methanol, ethyl acetate and water), from three plant parts, (fruit, leaf and bark) were obtained. Extracts were tested for total phenolic, flavonoid content and antioxidant activities using a battery of assays including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), total antioxidant capacity (TAC) (phosphomolybdenum) and metal chelating. Enzyme inhibitory effects were investigated using acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase as target enzymes. Results showed that the methanolic bark extract exhibited significant radical scavenging activity (DPPH: 202.09 ± 0.15; ABTS: 490.12 ± 0.18 mg Trolox equivalent (TE)/g), reducing potential (FRAP: 325.86 ± 4.36: CUPRAC: 661.82 ± 0.40 mg TE/g) and possessed the highest TAC (3.33 ± 0.13 mmol TE/g). The methanolic extracts were subjected to LC-DAD-MSn and NMR analysis. A two-column LC method was developed to separate constituents, allowing to identify and quantify forty-four and fifteen constituents in bark and fruits, respectively. Main compound in bark was epicatechin-3-O-sulphate and isolation of compound was performed to confirm its identity. Bark extract contained catechins, procyanidins, gallic acid derivatives and the sulfur containing spiroketal named breynins. Aerial parts mostly contained flavonoid glycosides. Considering the bioassays, the methanolic bark extract resulted a potent tyrosinase (152.79 ± 0.27 mg kojic acid equivalent/g), α-amylase (0.99 ± 0.01 mmol acarbose equivalent ACAE/g) and α-glucosidase (2.16 ± 0.01 mmol ACAE/g) inhibitor. In conclusion, methanol is able to extract the efficiently the phytoconstituents of B. retusa and the bark is the most valuable source of compounds.  相似文献   
804.
The present study investigates the quantitative aspects of an analytical procedure for the trace element characterization of suspended particulate matter (SPM) in natural waters. The procedure consists of the following steps: (1) ultrafiltration (UF) concentration; (2) splitt-flow thin (SPLITT) cell fractionation (SF) into different micronic–submicronic dimensional ranges; and (3) inductively coupled plasma–atomic emission spectrometry (ICP–AES) elemental determination on both the separated fractions and the bulk phase. One specific feature of the UF/SF steps is that they are gentle and thus preserve the complexity of the colloidal features of SPM samples as far as possible. The investigation was performed on a real SPM sample (Po River, Italy). Two SF modes were considered: the so called conventional SPLITT fractionation (CSF) mode and the full feed depletion SPLITT fractionation (FFDSF) mode. These differ in terms of resolution, time (both better in CSF as compared to FFDSF) and operating mode (FFDSF does not require a diluting carrier). Quantitative aspects of the UF step recovery and of the CSF and FFDSF modes were investigated in terms of total mass balance proving that only the FFDSF mode is currently satisfactory for quantitative purposes. Mass balance versus the following elements: Cd, Cr, Cu, Mn, Ni and Pb, was performed using ICP–AES over the 0.2–1.5 and 1.5–20 μm FFDSF SPM fractions, proving that the analytical procedure based on UF/FFDSF/ICP–AES is consistent and useful in the investigation of trace element distribution in different SPM dimensional ranges versus that of the bulk phase. The relevance of aggregation–solubility equilibria concerning colloids of SPM phase is emphasized and further improvement of the procedure is discussed.  相似文献   
805.
The rate of neutrino-electron elastic scattering interactions from 862 keV (7)Be solar neutrinos in Borexino is determined to be 46.0±1.5(stat)(-1.6)(+1.5)(syst)?counts/(day·100 ton). This corresponds to a ν(e)-equivalent (7)Be solar neutrino flux of (3.10±0.15)×10(9) cm(-2)?s(-1) and, under the assumption of ν(e) transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0?σ. A global solar neutrino analysis with free fluxes determines Φ(pp)=6.06(-0.06)(+0.02)×10(10) cm(-2)?s(-1) and Φ(CNO)<1.3×10(9) cm(-2)?s(-1) (95% C.L.). These results significantly improve the precision with which the Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.  相似文献   
806.
Ordered thin layers of a spirobifluorene derivative containing an amino group were formed by grafting them onto a self-assembled monolayer (SAM) of 11-mercaptoundecanoic acid (11-MUA) on gold. Either physical (H-bonding) or chemical bonding (activated by EDCl) was investigated. X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy confirmed that both methods can be used to effectively graft 2-amino-9,9'-spirobifluorene molecules onto the SAM surface, giving high surface coverages, with a significantly higher packing in the case of chemisorbed films. EIS measurements also showed that the covalently bonded spirobifluorene SAMs act as an effective barrier to both ion penetration and heterogeneous electron transfer.  相似文献   
807.
New silver(I) acylpyrazolonato derivatives displaying a mononuclear, polynuclear, or ionic nature, as a function of the ancillary azole ligands used in the synthesis, have been fully characterized by thermal analysis, solution NMR spectroscopy, solid‐state IR and NMR spectroscopies, and X‐ray diffraction techniques. These derivatives have been embedded in polyethylene (PE) matrix, and the antimicrobial activity of the composite materials has been tested against three bacterial strains (E. coli, P. aeruginosa, and S. aureus): Most of the composites show antimicrobial action comparable to PE embedded with AgNO3. Tests by contact and release tests for specific migration of silver from PE composites clearly indicate that, at least in the case of the PE, for composites containing polynuclear silver(I) additives, the antimicrobial action is exerted by contact, without release of silver ions. Moreover, PE composites can be re‐used several times, displaying the same antimicrobial activity. Membrane permeabilization studies and induced reactive oxygen species (ROS) generation tests confirm the disorganization of bacterial cell membranes. The cytotoxic effect, evaluated in CD34+ cells by MTT (3‐(4,5‐dimethylthiazole‐2‐yl)‐2,5‐diphenyltetrazoliumbromide) and CFU (colony forming units) assays, indicates that the PE composites do not induce cytotoxicity in human cells. Studies of ecotoxicity, based on the test of Daphnia magna, confirm tolerability of the PE composites by higher organisms and exclude the release of Ag+ ions in sufficient amounts to affect water environment.  相似文献   
808.
A validation study was carried out in order to evaluate the performances of a dissociation enhanced lanthanide fluorescence immunoassay (DELFIA) for rapid screening of 17 beta-estradiol in bovine serum. This validation was performed according to European Union (EU) Decision 2002/657/EC, which establishes criteria and procedures for determination of detection capability (CCbeta), selectivity/specificity, and applicability/ruggedness/stability for qualitative screening tests. To determine these performance characteristics, 20 blank serum samples of cattle were collected and spiked with 17 beta-estradiol at 40 pg/mL, corresponding to the maximum residue limit permitted by Italian legislation. According to the EU Decision CCbeta criterion, spiked samples must have <5% probability to be classified as a false negative. 17 beta-Estradiol was detected in each spiked sample, and the CCbeta results were <40 pg/mL. There was also no observed interference effect due to chemically related substances or from the matrix. Moreover, slight variations of some critical factors in the DELFIA procedure, deliberately introduced for ruggedness evaluation, did not result in any negative effect on the 17beta-estradiol detection. The proposed method is suitable for qualitative screening analysis of 17 beta-estradiol according to EU performance requirements.  相似文献   
809.
New and interesting 2-oxofuro[2,3-b]pyrroles and 19-methyl-15-oxa-20-azatricyclo[12.3.3.0(1,14)]icos-18-en-18-carboxylates have been obtained in good yields by the one-pot reaction, in basic medium, of 1,2-diaza-1,3-butadienes with diethyl or dimethyl acetylsuccinate or methyl 2-(1,3-dioxo-2-cyclotetradecyl)acetate, respectively, under mild conditions. Treatment of the same starting materials with diethyl 2-acetylglutarate, in acidic medium, afforded unknown 2-methylenepyrrole derivatives in high yields. Novel 4-(3-oxopropyl)-2,5-dimethyl-1H-pyrrole-3-carboxylates also have been achieved by reacting 1,2-diaza-1,3-butadienes with ethyl or methyl 4-acetyl-5-oxo-hexanoate.  相似文献   
810.
We have previously disclosed that some 6,7-dimethoxyisoquinoline derivatives are able to produce anticonvulsant effects in different animal models of epilepsy. Following these studies this paper describes the synthesis of a small series of new 1-aryl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines strictly related to previously reported analogues. This novel series of isoquinolines was designed on the basis of well defined structure-active relationship (SAR) information already acquired for this class of anticonvulsant agents. The pharmacological effects of the new synthesized compounds were evaluated against audiogenic seizures in Dilute Brown non-Agouti (DBA/2) mice. The preliminary pharmacological screening led to the identification of a new active molecule the 2-acetyl-1-(4'-methylphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (6d) that displayed significant anticonvulsant activity. Computational studies helped to rationalize these obtained pharmacological results.  相似文献   
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