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81.
Yousuke Ooyama 《Tetrahedron letters》2007,48(33):5791-5793
A new type of organic fluorophores, dialkylbenzo[b]naphtho[2,1-d]furan-6-one-type fluorophores, exhibiting strong blue and green emission in the solid state has been easily synthesized by an one-step reaction. The X-ray crystal structure demonstrated that the structural form with a chair-shape with the sterical hindered dialkyl substituents and the 9-dibutylamino group prevents the fluorophores from forming short intermolecular contacts and produces intense solid-state fluorescence emission. 相似文献
82.
Standard reference materials for foods and dietary supplements 总被引:1,自引:0,他引:1
Sharpless KE Thomas JB Christopher SJ Greenberg RR Sander LC Schantz MM Welch MJ Wise SA 《Analytical and bioanalytical chemistry》2007,389(1):171-178
Well-characterized certified reference materials are needed by laboratories in the food testing, dietary supplement, and nutrition
communities to facilitate compliance with labeling laws and improve the accuracy of information provided on product labels,
so that consumers can make good choices. As a result of the enactment of the Nutrition Labeling and Education Act of 1990
and the Infant Formula Act of 1980, the National Institute of Standards and Technology (NIST) worked to develop a series of
food-matrix standard reference materials (SRMs) characterized for nutrient concentrations. These include SRM 1544 Fatty Acids
and Cholesterol in a Frozen Diet Composite, SRM 1546 Meat Homogenate, SRM 1548a Typical Diet, SRM 1566b Oyster Tissue, SRM
1846 Infant Formula, SRM 1946 Lake Superior Fish Tissue, SRM 1947 Lake Michigan Fish Tissue, SRM 2383 Baby Food Composite,
SRM 2384 Baking Chocolate, SRM 2385 Slurried Spinach, and SRM 2387 Peanut Butter. With the enactment of the Dietary Supplement
Health and Education Act of 1994, NIST has been working to develop suites of dietary supplement SRMs characterized for active
and marker compounds and for toxic elements and pesticides, where appropriate. An updated SRM 1588b Organics in Cod Liver
Oil, a suite of ephedra-containing materials (SRMs 3240–3245), a carrot extract in oil (SRM 3276), and a suite of ginkgo-containing
materials (SRMs 3246–3248) are available. Several other materials are currently in preparation. Dietary supplements are sometimes
provided in forms that are food-like; for these, values may also be assigned for nutrients, for example SRM 3244 Ephedra-Containing
Protein Powder. Both the food-matrix and dietary supplement reference materials are intended primarily for validation of analytical
methods. They may also be used as “primary control materials” in assignment of values to in-house (secondary) control materials
to confirm accuracy and to establish measurement traceability to NIST. 相似文献
83.
Lolo M Pedreira S Vázquez BI Franco CM Cepeda A Fente CA 《Analytical and bioanalytical chemistry》2007,387(5):1933-1937
An efficiency extraction of fluoroquinolones in chicken muscle was achieved by pulverizing it in a freezer mill before treatment
with NaOH (10mM)/MeCN (1:1). The improvement of cryogenic grinding in the extraction was demonstrated for the same piece (whole
leg) of four chickens treated with enrofloxacin in equal doses. A confirmatory method based on high-performance liquid chromatography
tandem mass spectrometry (HPLC-MS/MS) was used to analyze the extracts. The chromatographic separation was achieved in 5min
with a Synergi Fusion-RP 80A (50 x 2mm, 4μm) column filled with a hybrid polymer. The HPLC was coupled with a detector based
in a quadrupole–linear ion trap Q-TRAP that allows a confirmatory detection according to the European legislation. The specificity
of the method was assessed by testing a number of representative blank muscle samples (n = 10) to verify the absence of potential interfering compounds. The limits of detection and quantitation were 2 and 5ng g-1 of quinolones in muscle samples, respectively. The chromatographic method was demonstrated to be linear for the range studied
(5–500ng g-1) with the P value for lack-of-fit in the ANOVA table greater or equal to 0.10 (calibration coefficient 0.9998 and 0.9996 for ciprofloxacin
and enrofloxacin, respectively). The mean intra-day relative standard deviation (RSD) (n = 6, c = 50ng g-1) was 6%; inter-day assay gave a RSD of 12%. The extraction and clean-up were carried out in one step with very satisfactory
recovery data (between 65 and 101%). 相似文献
84.
Pedraza A Sicilia MD Rubio S Pérez-Bendito D 《Analytical and bioanalytical chemistry》2007,389(7-8):2297-2302
A selective method for the determination of l-glutamate in foodstuffs has been developed. It was based on the competition established between the analyte and the dye Coomassie
brilliant blue G (CBBG) to interact with the surfactant didodecyldimethylammonium bromide (DDABr). The measurement parameter
was the amount of DDABr required to reach a given dye-to-surfactant binding degree. It was obtained by photometric titration
on the basis of the changes observed in the spectral characteristics of the dye when CBBG–DDABr aggregates were formed. The
calibration graph obtained was linear in the l-glutamate concentration interval 0.2–5 mM (detection limit 0.05 mM). The high selectivity of the proposed method (other amino
acids and food additives did not interfere at the concentrations present in foodstuffs) permitted the direct analysis of food
samples after dissolution of the analyte in hot water. The accuracy of the surfactant to the dye binding degree method was
demonstrated by determining l-glutamate in different kinds of foodstuffs (liquid and dried soups, seasonings, pasta sauces and dried mushroom creams) and
comparing the results obtained with those provided by the commercial Boehringer Mannheim essay. 相似文献
85.
86.
Rajeev K. Thakur C. Villette J.M. Aubry G. Delaplace 《Colloids and surfaces. A, Physicochemical and engineering aspects》2007,310(1-3):55-61
Formulation–composition map is an interesting tool to predict the nature of an emulsion, stability, viscosity and nevertheless to decide the mixing protocol of its ingredients. Information based on optimum formulation (environmental conditions at which the affinity of an emulsifier for oil and for aqueous phase is same), which is depicted through hydrophilic–lipophilic deviation (HLD) concept, is necessary to make a formulation–composition map of an emulsion. In order to apply this concept in food emulsions, it is necessary to determine characteristic constants of each component of the system, i.e. the aqueous phase, the oil phase and the emulsifier at equilibrium. In this work formulation–composition map of a sunflower oil–water–lecithin system, based on the knowledge of phase behavior of lecithin at equilibrium and emulsification, was made. The shape of inversion line on formulation–composition map was not the classical stair type rather an almost vertical inversion line at water-fraction (fw) near 0.20 was observed. It was supposed to be linked to the viscosity of oil phase which was 50 times the viscosity of aqueous phase. Additionally, emulsions were of oil-in-water (O/W) type for fw higher than 0.20, but their viscosity and the drop size behavior with respect to salt concentration as formulation variable did not show the existence of transitional inversion line on formulation–composition map. Such map in advance can certainly facilitate the guidelines for dynamic emulsification. 相似文献
87.
Surface activity of commercial food grade modified starches 总被引:1,自引:0,他引:1
Prochaska K Kedziora P Le Thanh J Lewandowicz G 《Colloids and surfaces. B, Biointerfaces》2007,60(2):187-194
An attempt to quantitative evaluation of the functionality of food grade chemically modified starches in the emulsion systems by estimation of their surface activity as well as the capability of thickening food products was the main purpose of this present work. It was stated that chemically modified starches reveal higher surface activity at air/water and toluene/water interfaces in comparison to the native starch. The increase of the degree of substitution of polar carboxyl groups as well as rather non-polar acetyl ones results in an enhance of surface activity. Starch sodium octenylsuccinate stands out from other investigated starches, in its excellent capability of lowering surface and interfacial tension. Cross-linked starches reveal excellent stabilisation activity at a pH range of 5.5–7.0 but their surface activity is lower than those of other modified starches. Acetylated starch as well as starch sodium octenylsuccinate reveal satisfactory thickening capability up to pH 4.5 and moreover their surface activity (especially of E 1450) allows us to recommend them as functional constituents of food emulsions. Low thickening capability of oxidised starches rather excluded these derivatives from the group of potential functional additives for food emulsions. 相似文献
88.
Wolfgang J. Philipp Pierre van Iwaarden Heinz Schimmel Nele Meeus Nadine Kollmorgen 《Accreditation and quality assurance》2007,12(3-4):134-138
The reliability of reference materials (RMs) depends on properties such as fitness, robustness, commutability, stability and
homogeneity. The development of RMs for microbiological analysis is especially challenged through questions around the stabilisation
and recovery of viable cells, the dispersion of precise numbers of cells, matrix effects and, when using molecular techniques,
the presence of nucleic acids (e.g. DNA) of dead and live target organisms. However, RMs are indispensable tools for quality
control in microbiological analysis. The Institute for Reference Materials and Measurements (IRMM), as part of the European
Commission, concentrates its efforts on the development of RMs to support the development, implementation and monitoring of
EU legislation. A special focus is given to highly precise RMs for presence/absence and enumeration tests in microbiological
food and water analysis. Another group of new RMs certified by the IRMM comprise DNA-based materials to control the identity
of micro-organisms in qualitative assays. All of these activities serve to improve quality control in microbiological analysis.
Presented at ‘BERM-10’, April 2006, Charleston, SC, USA. 相似文献
89.
石墨炉原子吸收光谱法测定食品级磷酸中铅 总被引:1,自引:0,他引:1
通过加入基体改进剂硝酸钯及采用氘灯作背景校正,直接用石墨炉原子吸收光谱法测定食品级磷酸中铅,回收率在94.0%~104.3%之间,RSD(n=6)≤3.90%,方法的检出限为0.15 pg,经与国家标准方法及电感耦合等离子发射光谱法测定结果对照,方法的准确度优于国家标准方法,检出限低于ICP-AES法. 相似文献
90.
Matteo Scampicchio Nathan S. Lawrence Alessandra Arecchi Stella Cosio Saverio Mannino 《Electroanalysis》2007,19(1):85-90
Cyclic voltammetry has been applied to the rapid measurement of free SH‐compounds in food flours samples. The protocol is based on the electrochemical adaptation of the Ellman's test, where the DTNB reacts with SH‐compounds present in food flour extracts, resulting in the equimolar production of the electroactive compound TNBA which, in turns, reacts with phenylendiamine. The reaction is found to provide an analytical signal from which to quantify indirectly free sulfhydryl compounds in flours extracts. 相似文献