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931.
Sauvinet V Parrot S Benturquia N Bravo-Moratón E Renaud B Denoroy L 《Electrophoresis》2003,24(18):3187-3196
gamma-Aminobutyric acid (GABA), glutamate (Glu), and L-aspartate (L-Asp) are three major amino acid neurotransmitters in the central nervous system. In this work, a method for the separation of these three neurotransmitters in brain microdialysis samples using a commercially available capillary electrophoresis (CE) system has been developed. Molecules were tagged on their primary amine function with the fluorogene agent naphthalene-2,3-dicarboxaldehyde (NDA), and, after separation by micellar electrokinetic chromatography, were detected by laser-induced fluorescence using a 442 nm helium-cadmium laser. The separation conditions for the analysis of derivatized neurotransmitters in standard solutions and microdialysates have been optimized, and this method has been validated on both pharmacological and analytical basis. The separation of GABA, Glu, and L-Asp takes less than 10 min by using a 75 mmol/L borate buffer, pH 9.2, containing 70 mmol/L SDS and 10 mmol/L hydroxypropyl-beta-cyclodextrin and + 25 kV voltage. The detection limits were 3, 15 nmol/L and, 5 nmol/L for GABA, Glu, and L-Asp, respectively. Moreover, submicroliter samples can be analyzed. This method allows a simple, rapid and accurate measurement of the three amino acid neurotransmitters for the in vivo brain monitoring using microdialysis sampling. 相似文献
932.
de Lima Melchiades Gabriela Angeli Valéria Weiss Colombo Mariana Koester Letícia Scherer 《Journal of Thermal Analysis and Calorimetry》2020,142(3):1249-1260
Journal of Thermal Analysis and Calorimetry - Compatibility is an important step in pre-formulation studies during the development of solid dosage forms. In the present study, we used thermal... 相似文献
933.
Voronina N. S. Nechaev A. I. Strel’nikov V. N. Val’tsifer V. A. 《Russian Journal of Applied Chemistry》2021,94(6):748-757
Russian Journal of Applied Chemistry - A copolymer of acrylamide (AA) and 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPSNa) was prepared by inverse emulsion radical polymerization in... 相似文献
934.
Surikov Vad. I. Surikov Val. I. Kuznetsova Yu. V. Semenyuk N. A. Lyakh O. V. Prokudina N. A. 《Russian Physics Journal》2021,64(3):376-380
Russian Physics Journal - The paper presents the research results of the temperature dependence of molar heat capacity at a constant pressure within the temperature range from 5 to 300 K for... 相似文献
935.
Ober Camille Samouillan Valérie Lacoste-Ferré Marie-Hélène Dandurand Jany Lacabanne Colette 《Journal of Thermal Analysis and Calorimetry》2021,144(4):1229-1238
Journal of Thermal Analysis and Calorimetry - The aim of this study was to develop an experimental protocol to determine specific and reproducible biomarkers of the oral mucosa using a combination... 相似文献
936.
Dr. Laura Zanetti-Polzi Dr. Ryan Djemili Dr. Stéphanie Durot Prof. Valérie Heitz Prof. Isabella Daidone Dr. Barbara Ventura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(72):17514-17524
The complexation processes of N,N’-dibutyl-1,4,5,8-naphthalene diimide ( NDI ) into two types of π-electron-rich molecular containers consisting of two Zn(II)-porphyrins connected by four flexible linkers of two different lengths, were characterized by means of absorption and emission spectroscopies and molecular dynamics simulation. Notably, the addition of NDI leads to a strong quenching of the fluorescence of both cages only when they are in an open conformation suitable for guest encapsulation, a situation triggered by silver(I) ions binding to the lateral triazoles. Molecular dynamics simulations confirm the fast binding of NDI , likely assisted by NDI -silver(I) interactions. Upon NDI complexation, the two porphyrin macrocycles get closer, with an optimized face to face orientation, suggesting an induced-fit mechanism through π–π interactions with the NDI aromatic cycle. Ultrafast transient absorption experiments allowed to identify the process of quenching of the Zn-porphyrin fluorescence as an efficient photoinduced electron transfer reaction between the cage porphyrin and the included NDI guest. The process occurs on fast and ultrafast time scales in the two complexes (1.5 ps and ≤300 fs) leading to a short-lived charge separated state (charge recombination lifetimes in the order of 30–40 ps). The combined computational and experimental approach used here is able to furnish a reliable model of the NDI -cage complexation mechanism and of the corresponding electron transfer reaction, attesting the allosteric control of both processes by the silver(I) ions. 相似文献
937.
938.
939.
Dr. Peng Xu Dr. Jana Korcová Dr. Peter Baráth Dr. Alžbeta Čížová Dr. Jana Valáriková Prof. Dr. Firdausi Qadri Meagan Kelly Dr. Robert D. O'Connor Prof. Edward T. Ryan Dr. Slavomír Bystrický Dr. Pavol Kováč 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(56):12946-12956
The lipopolysaccharide (LPS) of Vibrio cholerae O139, strain CIRS245, was isolated conventionally, and the lipid A was removed by mild acid hydrolysis (0.1 m NaOAc buffer containing 1 % SDS, pH 4.2, 95 °C, 8 h). The crude product was a complex mixture consisting mainly of constituent fragments of the O-specific polysaccharide-core (OSPc). The OSPc was only a minor component in the mixture. Two-stage purification of the crude OSPc by HPLC gave pure OSPc fragment of the LPS, as shown by NMR spectroscopy, analytical HPLC and ESI-MS. This material is the purest OSPc fragment of the LPS from Vibrio cholerae O139 reported to date. The purified OSPc was readily converted to the corresponding methyl squarate derivative and the latter was conjugated to BSA. The conjugate, when examined by ELISA, showed immunoreactivity with sera from patients in Bangladesh recovering from cholera caused by V. cholerae O139, but not O1. 相似文献
940.
Dr. Alain Manceau Dr. Paco Bustamante Dr. Ahmed Haouz Prof. Dr. Jean Paul Bourdineaud Maria Gonzalez-Rey Dr. Cyprien Lemouchi Prof. Dr. Isabelle Gautier-Luneau Valérie Geertsen Elodie Barruet Dr. Mauro Rovezzi Dr. Pieter Glatzel Dr. Serge Pin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(4):997-1009
Of all divalent metals, mercury (HgII) has the highest affinity for metallothioneins. HgII is considered to be enclosed in the α and β domains as tetrahedral α-type Hg4Cys11-12 and β-type Hg3Cys9 clusters similar to CdII and ZnII. However, neither the four-fold coordination of Hg nor the existence of Hg–Hg atomic pairs have ever been demonstrated, and the HgII partitioning among the two protein domains is unknown. Using high energy-resolution XANES spectroscopy, MP2 geometry optimization, and biochemical analysis, evidence for the coexistence of two-coordinate Hg-thiolate complex and four-coordinate Hg-thiolate cluster with a metacinnabar-type (β-HgS) structure in the α domain of separate metallothionein molecules from blue mussel under in vivo exposure is provided. The findings suggest that the CXXC claw setting of thiolate donors, which only exists in the α domain, acts as a nucleation center for the polynuclear complex and that the five CXC motifs from this domain serve as the cluster-forming motifs. Oligomerization is driven by metallophilic Hg⋅⋅⋅Hg interactions. Our results provide clues as to why Hg has higher affinity for the α than the β domain. More generally, this work provides a foundation for understanding how metallothioneins mediate mercury detoxification in the cell under in vivo conditions. 相似文献