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101.
Nonlinear Dynamics - This is the first paper of a trilogy intended by the authors in what concerns a unified approach to the stability of thermoelastic arched beams of Bresse type under... 相似文献
102.
103.
Gabriel de Oliveira Isac Moraes Larissa Meirelles Rodrigues da Silva Álvaro José dos Santos-Neto Fábio Herbst Florenzano Eduardo Costa Figueiredo 《Analytical and bioanalytical chemistry》2013,405(24):7687-7696
A new restricted access molecularly imprinted polymer coated with bovine serum albumin (RAMIP-BSA) was developed, characterized, and used for direct analysis of chlorpromazine in human plasma samples. The RAMIP-BSA was synthesized using chlorpromazine, methacrylic acid, and ethylene glycol dimethacrylate as template, functional monomer, and cross-linker, respectively. Glycerol dimethacrylate and hydroxy methyl methacrylate were used to promote a hydrophilic surface (high density of hydroxyl groups). Afterward, the polymer was coated with BSA using glutaraldehyde as cross-linker, resulting in a protein chemical shield around it. The material was able to eliminate ca. 99 % of protein when a 44-mg mL?1 BSA aqueous solution was passed through it. The RAMIP-BSA was packed in a column and used for direct analysis of chlorpromazine in human plasma samples in an online column switching high-performance liquid chromatography system. The analytical calibration curve was prepared in a pool of human plasma samples with chlorpromazine concentrations ranging from 30 to 350 μg L?1. The correlation coefficient obtained was 0.995 and the limit of quantification was 30 μg L?1. Intra-day and inter-day precision and accuracy presented variation coefficients and relative errors lower than 15 % and within ?15 and 15 %, respectively. The sample throughput was 3 h?1 (sample preparation and chromatographic analysis steps) and the same RAMIP-BSA column was efficiently used for about 90 cycles. 相似文献
104.
Tardioli Paulo W. Zanin Gisella M. de Moraes Flávio F. 《Applied biochemistry and biotechnology》2000,84(1-9):1003-1019
Cyclodextrin-glycosyl-transferase (EC2.4.1.19), produced by Wacker (Munich, Germany), was purified by biospecific affinity
chromatography with β-cyclodextrin (β-CD) as ligand, and immobilized into controlled pore silica particles (0.42 mm). This
immobilized enzyme (IE) had 4.7 mg of protein/g of support and a specific activity of 8.6 μmol of β-CD/(min·gIF) at 50°C, pH 8.0. It was used in a fluidized-bed reactor (FBR) at the same conditions for producing cyclodextrins (CDs) with
10% (w/v) maltodextrin solution as substrate. Bed expansion was modeled by the Richardson and Zaki equation, giving a good
fit in two distin ctranges of bed porosities. The minimum fluidization velocity was 0.045 cm/s, the bed expansion coefficient
was 3.98, and the particle terminal velocity was 2.4 cm/s. The FBR achieved high productivity, reaching in only 4 min of residence
time the same amount of CDs normally achieved in a batch reactor with free enzyme after 24h of reaction, namely, 10.4 mM β-CD
and 2.3 mM γ-CD. 相似文献
105.
By mapping a Hubbard-like model describing a two-component polymer in the presence of strong enough electron-phonon interactions (κ) onto the system of two coupled nonlinear Schrödinger equations with U(2) symmetry group, some nontrivial correlations between topological solitons mediated charge Q and spin S degrees of freedom are obtained. Namely, in addition to a charge fractionalization and reentrant like behavior of both Q(κ) and S(κ), the model also predicts a decrease of soliton velocity with κ as well as spin-charge conversion effects which manifest themselves through an explicit S(Q,Ω) dependence (with Ω being a mixing angle between spin-up and spin-down electron amplitudes). A possibility to observe the predicted effects in low-dimensional systems with charge and spin soliton carriers is discussed. 相似文献
106.
Luciano de Moraes Renato Garcia Leonardo Ensslin Mrio Jos da Conceio Stella Maris de Carvalho 《European Journal of Operational Research》2010,200(2):89
In developing countries, approximately half of the healthcare equipments are not in full use and the main cause of this is the inadequate management of them. The Clinical Engineering might face this problem in the healthcare environment analyzing the equipment with a health technological process perspective to identify opportunities of improvements. Generally, the inadequate management is a result of lack of systemized and contextualized information about the health technological process. The effort to make an adequate management generates an increasing interest in the use of benchmarker. Currently, the benchmarkers used by the Clinical Engineering are not representative of a health technological process as a whole. Health technological process concept is stated in this article. The multicriteria analysis methodology MCDA (Multicriteria Decision Aid) is used to obtain benchmarkers and to identify opportunities of improvements, thus generating conditions for that the Clinical Engineering consolidates its relevant contribution for the healthcare. 相似文献
107.
Diogo P. Moraes Juliana S. F. Pereira Liange O. Diehl Márcia F. Mesko Valderi L. Dressler José Neri G. Paniz Guenter Knapp Érico M. M. Flores 《Analytical and bioanalytical chemistry》2010,397(2):563-570
In this work, three sample preparation methods were evaluated for further halogen determination in elastomers containing high
concentrations of carbon black. Samples of nitrile-butadiene rubber, styrene-butadiene rubber, and ethylene-propylene-diene
monomer elastomers were decomposed using oxygen flask combustion and microwave-induced combustion (MIC) for further Br and
Cl determination by ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP OES), and inductively
coupled plasma mass spectrometry (ICP-MS). Extraction assisted by microwave radiation in closed vessels was also evaluated
using water or alkaline solution. Digestion by MIC was carried out using 50 mmol l−1 (NH4)2CO3 as the absorbing solution. The effect of the reflux step was also evaluated. Accuracy was evaluated using certified reference
materials with polymeric matrix composition and by comparison of results using neutron activation analysis. Agreement for
Br and Cl was better than 95% by MIC using 5 min of reflux, and no statistical difference was found using IC, ICP OES, and
ICP-MS for determination of both analytes. For MIC, the relative standard deviation (RSD) was lower than 5%. Using extraction
in closed vessels, a high amount of residues was observed, and recoveries were lower than 45% for both analytes. For oxygen
flask combustion, the agreement was similar using MIC but RSD was higher (20%). The residual carbon content, an important
parameter used to evaluate the digestion efficiency, was always below 1% for MIC. Using MIC, it was possible to digest elastomers
with high efficiency, resulting in a single solution suitable for halogen determination by different techniques. 相似文献
108.
Rare earth element (REE) concentrations in United States Geological Survey (USGS) rock standards AGV-1, GSP-1, G-2 and PCC-1 were determined by isotope dilution mass spectrometry (IDMS), neutron activation and inductively coupled argon plasma atomic emission spectrometric techniques. The procedure involved acid digestion of samples in PTFE pressure bombs and group separation of REEs by an ion-exchange method. For IDMS an additional separation step using α-hydroxyisobutyric acid as an eluent was used in a cation-exchange column to split the REEs into subgroups. Comparison of the results with literature values showed that the IDMS values are the most precise and accurate. However, the precisions and the accuracies of the other techniques are acceptable. 相似文献
109.
Abstract— The mutational interactions between near-ultraviolet (near-UV, 334 nm, 365 nm) radiation and DNA damaging agents (far-UV (254 nm) and ethyl-methanesulphonate (EMS)) were studied in strains of Escherichia coli B/r trp thy with different susceptibilities to near-UV-induced growth delay (wild-type, rel and srd ). Far-UV induced reversion to tryptophan independence is reduced while forward mutation to streptomycin is enhanced by prior exposure of the rel+ srd+ strains to near-UV radiation. The observed interactions are reduced ( rel ) or absent ( srd ) in the two mutant strains as are the corresponding growth and macromolecular synthesis delays normally observed after near-UV treatment. Quantitatively, the degree of interaction induced by near-UV pre-treatment correlates closely with the degree of protein synthesis inhibition. We propose a mechanism for the contrasting interactions at the two genetic loci based on the different pathways by which pre-mutagenic lesions may be processed. The primary chromophore for the mutational interactions would appear to be 4-thiouracil-containing transfer RNA. 相似文献
110.
A flow injection potentiometric procedure for saccharin determination in dietary products is proposed. Saccharin is precipitated as mercurous saccharinate and the excess of the mercurous cation is potentiometrically measured using a silver wire coated with a mercury film as the working electrode. A filter unit is used to avoid contact between the precipitate and the electrode surface. With relocation in the flow manifold, the accumulated precipitate is removed on-line. Sucrose, glucose, aspartame, sodium cyclamate and sodium benzoate do not interfere when present in amounts similar to those observed in commercial products. Results are comparable with those obtained by UV-spectrophotometry and the correlation coefficient between methods is equal to 0.9930. A linear relationship between DeltaE (mV) and the logarithm of saccharin concentration was obtained in the saccharin concentration range 2 x 10(-3) - 1 x 10(-2)M. The sampling frequency is 60/hour and only 0.76 mg of Hg(2+)(2) is consumed in each determination. 相似文献