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271.
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273.
Darrah Johnson‐McDaniel Dr. Sara Comer Prof. Joseph W. Kolis Prof. Tina T. Salguero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17560-17564
We describe the first hydrothermal synthesis of CaCuSi4O10 as micron‐scale clusters of thin platelets, distinct from morphologies generated under salt‐flux or solid‐state conditions. The hydrothermal reaction conditions are surprisingly specific: too cold, and instead of CaCuSi4O10, a porous calcium copper silicate forms; too hot, and calcium silicate (CaSiO3) forms. The precursors also strongly impact the course of the reaction, with the most common side product being sodium copper silicate (Na2CuSi4O10). Optimized conditions for hydrothermal CaCuSi4O10 formation from calcium chloride, copper(II) nitrate, sodium silicate, and ammonium hydroxide are 350 °C at 3000 psi for 72 h; at longer reaction times, competitive delamination and exfoliation causes crystal fragmentation. These results illustrate that CaCuSi4O10 is an even more unique material than previously appreciated. 相似文献
274.
Tina S. Guion Madlene U. Koller Rene J. Lachicotte Robin N. Rutledge Karen C. Hildebran Phuong H. Le 《合成通讯》2013,43(9):1753-1762
ortho-Toluic acid was dimetalated with excess lithium diisopropylamide, and the resulting intermediate was condensed with a variety of aromatic esters to afford new substituted 2-(2-oxo-2-phenylethyl)benzoic acids (ortho-phenacylbenzoic acids). 相似文献
275.
Tina Suominen Markus Haapala Anna Takala Raimo A. Ketola Risto Kostiainen 《Analytica chimica acta》2013
A new and simple APPI interface employing commercially available hardware is used to combine GC to MS. The feasibility of the method is demonstrated in the analysis of urine samples for neurosteroids as their trimethylsilyl (TMS) derivatives. The effect of different dopants (chlorobenzene, toluene, anisole) on the ionization of the TMS derivatives was investigated. With chlorobenzene, the TMS derivatives produced intense molecular ions with minimal fragmentation, and chlorobenzene was selected as best dopant. Protonated molecules in addition to intense molecular ions were produced with toluene and anisole. The performance of the method was verified in the analysis of human urine samples. Chromatographic performance was good with peak half-widths of 3.6–4.3 s, linearity (r2 > 0.990) was acceptable, limits of detection (LODs) were in the range of 0.01–10 ng mL−1, and repeatability was good with relative standard deviations (rsd%) below 22%. The results show that the method is well suited for the determination of neurosteroids in biological samples. 相似文献
276.
Banu Bayram Gulay Ozkan Tina Kostka Esra Capanoglu Tuba Esatbeyoglu 《Molecules (Basel, Switzerland)》2021,26(13)
The important roles of food packaging are food protection and preservation during processing, transportation, and storage. Food can be altered biologically, chemically, and physically if the packaging is unsuitable or mechanically damaged. Furthermore, packaging is an important marketing and communication tool to consumers. Due to the worldwide problem of environmental pollution by microplastics and the large amounts of unused food wastes and by-products from the food industry, it is important to find more environmentally friendly alternatives. Edible and functional food packaging may be a suitable alternative to reduce food waste and avoid the use of non-degradable plastics. In the present review, the production and assessment of edible food packaging from food waste as well as fruit and vegetable by-products and their applications are demonstrated. Innovative food packaging made of biopolymers and biocomposites, as well as active packaging, intelligent packaging, edible films, and coatings are covered. 相似文献
277.
Pech H Vazquez MG Van Buren J Shi L Ivey MM Salmassi TM Pasek MA Foster KL 《Journal of chromatographic science》2011,49(8):573-581
Historically, it was assumed that reactive, inorganic phosphorus present in pristine environments was solely in the form of orthophosphate. However, this assumption contradicts theories of biogenesis and the observed metabolic behavior of select microorganisms. This paper discusses the role of ion chromatography (IC) in elucidating the oxidation-reduction cycle of environmental phosphorus. These methods employ suppressed-IC, coupled with tandem conductivity and electrospray mass spectrometry detectors to identify and quantify phosphorus oxyanions in natural water, synthetic cosmochemical, and biological samples. These techniques have been used to detect phosphite and orthophosphate in geothermal hot springs. Hypophosphite, phosphite, and orthophosphate have been detected in synthetic schreibersite corrosion samples, and termite extract supernatant. Synthetic schreibersite corrosion samples were also analyzed for two poly-phosphorus compounds, hypophosphate and pyrophosphate, and results show these samples did not contain concentrations above the 1.3 and 2.0 μM respective 3σ limit of detection. These methods are readily adaptable to a variety of matrices, and contribute to the elucidation of the oxidation-reduction cycle of phosphorus oxyanions in the environment. In contrast to most studies, these techniques have been used to show that phosphorus actively participates in redox processes in both the biological and geological world. 相似文献
278.
Herdes C Ferreiro-Rangel CA Düren T 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):6738-6743
The isosteric enthalpy of adsorption for neopentane at relative pressures down to 3 × 10(-8) in MCM-41 was predicted for the temperature range from -15 to 0 °C. At such low pressures and temperatures, experimental measurements become problematic for this system. We used an atomistic model for MCM-41 obtained by means of a kinetic Monte Carlo method mimicking the synthesis of the material. The model was parametrized to represent experimental nitrogen adsorption isotherms at 77 K using grand canonical Monte Carlo simulations. The simulated isosteric enthalpy of adsorption shows very good agreement with available experimental data, demonstrating that GCMC simulations can predict heats of adsorption for conditions that are challenging for experimental measurements. Additional insights into the adsorption mechanisms, derived from energetic analysis at the molecular level, are also presented. 相似文献
279.
Seyednejad H Ji W Schuurman W Dhert WJ Malda J Yang F Jansen JA van Nostrum C Vermonden T Hennink WE 《Macromolecular bioscience》2011,11(12):1684-1692
Scaffolds based on a novel functionalized polyester, pHMGCL, are electrospun and characterized morphologically and physically. In vitro degradation studies of pHMGCL films show considerable mass loss and molecular weight reduction within 70 weeks. Scaffolds composed of fibers with uniform diameter (≈ 900 nm) and with melting temperatures higher than body temperature are prepared. As an indication for the feasibility of this material for regenerative medicine approaches, articular chondrocytes are seeded onto electrospun pHMGCL scaffolds. Chondrocytes attach to the fibers and re-differentiate as demonstrated by the production of GAG and collagen type II within four weeks of in vitro culture. Hydrophilic pHMGCL scaffolds may thus be useful for tissue engineering applications. 相似文献
280.
Tina KosjekEster Heath 《Trends in analytical chemistry : TRAC》2011,30(7):1065
We review the literature on the analysis of pharmaceutically-derived cytostatic compounds in the environment. Cytostatics are a major class of chemotherapy drugs used extensively in the fight against cancer. They are a broad group of mostly organic compounds possessing a diverse range of physico-chemical parameters. Their differences and their presence in the environment in trace amounts make their determination in complex matrices a major challenge. Despite the good scientific foundations laid by those in the field, it is apparent that past research has focused mainly on hospital effluents and few have analyzed environmental samples. Importantly, no study has looked at environmental transformation products that, along with human metabolites, could contribute to overall toxicity. To improve understanding of the chemodynamics of cytostatics in natural waters, it is essential to have more data on the occurrence and the fate of these compounds, including their human metabolites and environmental transformation products. This approach will require advanced sampling techniques and state-of-the-art analytical tools, including the latest separation methods and cutting-edge instrumentation. 相似文献