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561.
Differential scanning calorimetry characterization of water-in-oil emulsions from Mexican crude oils
Javier A. Díaz-Ponce Eugenio A. Flores Alfonso Lopez-Ortega Jose G. Hernández-Cortez Arquimides Estrada Laura V. Castro Flavio Vazquez 《Journal of Thermal Analysis and Calorimetry》2010,102(3):899-906
A simplified equation relating water droplet size distribution to crystallization temperature, determined from differential
scanning calorimetry (DSC) curves of aqueous emulsions of petroleum is reported in this article. A series of water-in-oil
(W/O) emulsions was prepared by dispersion of water in different Mexican crude oils; in a classical DSC experiment, these
emulsions were submitted to a regular heating and cooling cycle within temperatures including freezing and heating of dispersed
water. The Z-average diameters of the water drops (D
dz) were estimated this way and correlated with petroleum composition. 相似文献
562.
Andrea Cappelli Marco Paolino Paolo Anzini Germano Giuliani Salvatore Valenti Marianna Aggravi Alessandro Donati Raniero Mendichi Lucia Zetta Antonella Caterina Boccia Fabio Bertini Filippo Samperi Salvatore Battiato Eugenio Paccagnini Salvatore Vomero 《Journal of polymer science. Part A, Polymer chemistry》2010,48(11):2446-2461
Three methyl end‐capped oligo(ethylene glycol) (MOEG) ethers ( 1b‐d ) and a methoxyderivative ( 1a ) of benzofulvene monomer BF3k were synthesized and induced to polymerize spontaneously by solvent removal to obtain soluble π‐stacked polymers bearing densely grafted MOEG side chains (poly‐ 1b – d ) and model polymer poly‐ 1a. The physicochemical features (e.g., solubility, NMR, MALDI‐TOF, and absorption/emission spectra, as well as MWD, conformation plot, and thermal properties) of the synthesized polymers were compared in a structure‐property relationship study. This approach afforded the following evidence. The structure of poly‐ 1a – d is very similar to that of BF3k , suggesting that the polymerization mechanism is not affected by the presence of the electron‐rich methoxy group or bulkier MOEG side chains. However, the latter appear to be capable of affecting the conformational behavior of the polymer backbone. The solubility of poly‐ 1a – d depends on the number of the oligo(ethylene glycol) monomeric units. In particular, poly‐ 1d , featuring a long MOEG side chain (n = 9), shows an amphiphilic character and is soluble in a number of organic solvents, whereas it interacts with water to give isolated macromolecules in equilibrium with nanosized water‐soluble aggregates. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2446–2461, 2010 相似文献
563.
Elías Quezada Dolores Via Giovanna Delogu Fernanda Borges Lourdes Santana Eugenio Uriarte 《Helvetica chimica acta》2010,93(2):309-313
The Mitsunobu reaction is an important tool in carbocyclic nucleoside chemistry for the direct coupling of alcohols with heterocyclic bases under mild conditions. Chemical evidences for an unusual competitive O2‐ vs. N1‐alkylation of 3‐substituted pyrimidines is presented. 相似文献
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565.
Mariafrancesca Scalise Raffaella Scanga Lara Console Michele Galluccio Lorena Pochini Cesare Indiveri 《Molecules (Basel, Switzerland)》2021,26(21)
The localization of membrane transporters at the forefront of natural barriers makes these proteins very interesting due to their involvement in the absorption and distribution of nutrients and xenobiotics, including drugs. Over the years, structure/function relationship studies have been performed employing several strategies, including chemical modification of exposed amino acid residues. These approaches are very meaningful when applied to membrane transporters, given that these proteins are characterized by both hydrophobic and hydrophilic domains with a different degree of accessibility to employed chemicals. Besides basic features, the chemical targeting approaches can disclose information useful for pharmacological applications as well. An eminent example of this picture is the histidine/large amino acid transporter SLC7A5, known as LAT1 (Large Amino Acid Transporter 1). This protein is crucial in cell life because it is responsible for mediating the absorption and distribution of essential amino acids in peculiar body districts, such as the blood brain barrier and placenta. Furthermore, LAT1 can recognize a large variety of molecules of pharmacological interest and is also considered a hot target for drugs due to its over-expression in virtually all human cancers. Therefore, it is not surprising that the chemical targeting approach, coupled with bioinformatics, site-directed mutagenesis and transport assays, proved fundamental in describing features of LAT1 such as the substrate binding site, regulatory domains and interactions with drugs that will be discussed in this review. The results on LAT1 can be considered to have general applicability to other transporters linked with human diseases. 相似文献
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