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991.
A discrete heterodinuclear Al (III)/Ir (III) complex shows bright-orange light emission when used as an active layer in host-dopant assembly organic light-emitting diodes based on a solution process. 相似文献
992.
Jang Hyeon Seok Choi Seong Yeon Jeong Birang Lee Jiho Kwon Yongsoo Yang Heejung 《Chemistry of Natural Compounds》2022,58(5):866-869
Chemistry of Natural Compounds - Two new pregnane glycosides (1 and 2) were isolated from Stapelia gigantea. The structures were determined by 1D and 2D NMR spectral analysis. The absolute... 相似文献
993.
Herein,we designed a core-shell structured bottlebrush copolymer (BBP),which is composed of rubbery poly(butyl acrylate) (PBA)core and an epoxy miscible/reactive poly(glycidyl methacrylate) (PGMA) shell,as an epoxy toughening agent.The PGMA shell allows BBP to be uniformly dispersed within the epoxy matrix and to react with the epoxy groups,while the rubbery PBA block simultaneously induced nanocavitation effect,leading to improvement of mechanical properties of the epoxy resin.The mechanical properties were measured by the adhesion performance test,and the tensile and fracture test using universal testing machine.When BBP additives were added to the epoxy resin,a significant improvement in the adhesion strength (2-fold increase) and fracture toughness (2-fold increase in Klc and 5-fold increase in Glc)compared to the neat epoxy was observed.In contrast,linear additives exhibited a decrease in adhesion strength and no improvement of fracture toughness over the neat epoxy.Such a difference in mechanical performance was investigated by comparing the morphologies and fracture surfaces of the epoxy resins containing linear and BBP additives,confirming that the nanocavitation effect and void formation play a key role in strengthening the BBP-modified epoxy resins. 相似文献
994.
Maharjan Ravi Tripathi Julu Nam Ah Kim Kyeung Eui Park Seong Hoon Jeong 《Molecules (Basel, Switzerland)》2021,26(2)
The solubility and dissolution thermodynamics of new c-Met inhibitor, ABN401, were determined in eleven solvents and Transcutol® HP–water mixture (TWM) from 298.15 to 318.15 K. The experimental solubilities were validated using five mathematical models, namely modified Apelblat, van’t Hoff, Buchowski–Ksiazaczak λh, Yalkowsky, and Jouyban–Acree van’t Hoff models. The experimental results were correlated and utilized further to investigate the feasibility of nanosuspension formation using liquid anti-solvent precipitation. Thermodynamic solubility of ABN401 increased significantly with the increase in temperature and maximum solubility was obtained with Transcutol® HP while low solubility in was obtained water. An activity coefficient study indicated that high molecular interaction was observed in ABN401–Transcutol® HP (THP). The solubility increased proportionately as the mole fraction of Transcutol® HP increased in TWM, which was also supported by a solvent effect study. The result suggested endothermic and entropy-driven dissolution. Based on the solubility, nanosuspension was designed with Transcutol® HP as solvent, and water as anti-solvent. The mean particle size of nanosuspension decreased to 43.05 nm when the mole fraction of ABN401 in THP, and mole fraction of ABN401 in TWM mixture were decreased to 0.04 and 0.1. The ultrasonicated nanosuspension appeared to give comparatively higher dissolution than micronized nanosuspension and provide a candidate formulation for in vivo purposes. 相似文献
995.
In this study, we report pH-responsive metal-based biopolymer nanoparticles (NPs) for tumor-specific chemotherapy. Here, aminated hyaluronic acid (aHA) coupled with 2,3-dimethylmaleic anhydride (DMA, as a pH-responsive moiety) (aHA-DMA) was electrostatically complexed with ferrous chloride tetrahydrate (FeCl2/4H2O, as a chelating metal) and doxorubicin (DOX, as an antitumor drug model), producing DOX-loaded Fe-based hyaluronate nanoparticles (DOX@aHA-DMA/Fe NPs). Importantly, the DOX@aHA-DMA/Fe NPs improved tumor cellular uptake due to HA-mediated endocytosis for tumor cells overexpressing CD44 receptors. As a result, the average fluorescent DOX intensity observed in MDA-MB-231 cells (with CD44 receptors) was ~7.9 × 102 (DOX@HA/Fe NPs, without DMA), ~8.1 × 102 (DOX@aHA-DMA0.36/Fe NPs), and ~9.3 × 102 (DOX@aHA-DMA0.60/Fe NPs). Furthermore, the DOX@aHA-DMA/Fe NPs were destabilized due to ionic repulsion between Fe2+ and DMA-detached aHA (i.e., positively charged free aHA) in the acidic environment of tumor cells. This event accelerated the release of DOX from the destabilized NPs. Our results suggest that these NPs can be promising tumor-targeting drug carriers responding to acidic endosomal pH. 相似文献
996.
Baek TJ Park PY Han KN Kwon HT Seong GH 《Analytical and bioanalytical chemistry》2008,390(5):1373-1378
We describe a DNA microarray system using a bipolar integrated circuit photodiode array (PDA) chip as a new platform for DNA
analysis. The PDA chip comprises an 8 × 6 array of photodiodes each with a diameter of 600 μm. Each photodiode element acts
both as a support for an immobilizing probe DNA and as a two-dimensional photodetector. The usefulness of the PDA microarray
platform is demonstrated by the detection of high-risk subtypes of human papilloma virus (HPV). The polymerase chain reaction
(PCR)-amplified biotinylated HPV target DNA was hybridized with the immobilized probe DNA on the photodiode surface, and the
chip was incubated in an anti-biotin antibody-conjugated gold nanoparticle solution. The silver enhancement by the gold nanoparticles
bound to the biotin of the HPV target DNA precipitates silver metal particles at the chip surfaces, which block light irradiated
from above. The resulting drop in output voltage depends on the amount of target DNA present in the sample solution, which
allows the specific detection and the quantitative analysis of the complementary target DNA. The PDA chip showed high relative
signal ratios of HPV probe DNA hybridized with complementary target DNA, indicating an excellent capability in discriminating
HPV subtypes. The detection limit for the HPV target DNA analysis improved from 1.2 nM to 30 pM by changing the silver development
time from 5 to 10 min. Moreover, the enhanced silver development promoted by the gold nanoparticles could be applied to a
broader range of target DNA concentration by controlling the silver development time.
Figure An optical image of the PDA chip and target DNA detection through silver enhancement
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
997.
Han Y Jiang J Lee SS Ying JY 《Langmuir : the ACS journal of surfaces and colloids》2008,24(11):5842-5848
A reverse microemulsion method is reported for preparing monodispersed silica-coated gold (or silver) nanoparticles without the use of a silane coupling agent or polymer as the surface primer. This method enables a fine control of the silica shell thickness with nanometer precision. As compared to the St?ber method reported for direct silica coating, which can only coat large gold particles ( approximately 50 nm in diameter) at low concentrations (<1.5 x 10(10) particles/mL), this new approach is capable of coating gold particles of a wide range of sizes (from 10 to 50 nm) at a much higher concentration ( approximately 1.5 x 10(13) particles/mL). Moreover, it enables straightforward surface functionalization via co-condensation between tetraethyl orthosilicate and another silane with the desired functional groups. The functional groups introduced by this method are readily accessible and thus useful for various applications. 相似文献
998.
Photo-oxidation of amino acids is known to generate reactive protein radicals that lead to lethal disorders. We investigated photoionization of hydrated phenylglycine complexes in the gas phase and found that the excess internal energy from photoionization drives decarboxylation in competition with dehydration. We also found that, in decarboxylation, the solvent migrates a large distance from the C terminus of the neutral amino acid to the N terminus of the newly formed radical cation upon ionization, prior to the departure of the carboxyl group. It is noted that a solvent does not just act as a passive medium bound to the solute molecule but actively pursues its own course of action upon external perturbation that changes its chemical environment. 相似文献
999.
1000.
Miniature fiber-optic high temperature sensor based on a hybrid structured Fabry-Perot interferometer 总被引:1,自引:0,他引:1
A miniature Fabry-Perot (FP) interferometric fiber-optic sensor suitable for high-temperature sensing is proposed and demonstrated. The sensor head consists of two FP cavities formed by fusion splicing a short hollow-core fiber and a piece of single-mode fiber at a photonic crystal fiber in series. The reflection spectra of an implemented sensor are measured at several temperatures and analyzed in the spatial frequency domain. The experiment shows that the thermal-optic effect of the cavity material is much more appreciable than its thermal expansion. The temperature measurements up to 1000 degrees C with a step of 50 degrees C confirm that it could be applicable as a high-temperature sensor. 相似文献