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931.
Impedance study of SrTi1−xFexO3−δ (x = 0.05 to 0.80) mixed ionic-electronic conducting model cathode
SrTi1?xFexO3?δ (STF) model cathodes, with compositions of x = 0.05 to 0.80 were deposited onto single crystal yttria stabilized zirconia by pulsed layer deposition as dense films with well defined area and thickness and studied by electrochemical impedance spectroscopy as a function of electrode geometry, temperature and pO2. The STF cathode was observed to exhibit typical mixed ionic-electronic behavior with the electrode reaction occurring over the full electrode surface area rather than being limited to the triple phase boundary. The electrode impedance was observed to be independent of electrode thickness and to the introduction of CGO interlayers and inversely proportional to the square of the electrode diameter, pointing to surface exchange limited kinetics. Values for the surface exchange coefficient, k, were calculated and found to be comparable in magnitude to those exhibited by other popular mixed ionic-electronic conductors such as (La,Sr)(Co,Fe)O3, thereby, confirming the suitability of STF as a model mixed conducting cathode material. The surface exchange coefficient, k, was also found to be insensitive to orders of magnitude change in both bulk electronic and ionic conductivities. 相似文献
932.
Chang Heon Lee Kih Soo Joe Won Ho Kim Euo Chang Jung Kwang Yong Jee 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(2):361-370
A sequential separation procedure has been developed for the determination of transuranic elements and fission products in
uranium metal ingot samples from an electrolytic reduction process for a metallization of uranium dioxide to uranium metal
in a medium of LiCl-Li2O molten salt at 650 °C. Pu, Np and U were separated using anion-exchange and tri-n-butylphosphate (TBP) extraction chromatography.
Cs, Sr, Ba, Ce, Pr, Nd, Sm, Eu, Gd, Zr and Mo were separated in several groups from Am and Cm using TBP and di(2-ethylhexyl)phosphoric
acid (HDEHP) extraction chromatography. Effect of Fe, Ni, Cr and Mg, which were corrosion products formed through the process,
on the separation of the analytes was investigated in detail. The validity of the separation procedure was evaluated by measuring
the recovery of the stable metals and 239Pu, 237Np, 241Am and 244Cm added to a synthetic uranium metal ingot dissolved solution. 相似文献
933.
The objective of this study was to evaluate the performance of a photocatalysis/H2O2/metal membrane hybrid system in the degradation of humic acid. A metal membrane of nominal pore size 0.5 μm was used in the
experiment for separation of TiO2 particles. Hydrogen peroxide was tested as an oxidant. The efficiency of removal of CODCr and color increased rapidly for initial hydrogen peroxide concentrations up to 50 mg L−1. The efficiency of removal of CODCr and color by 50 mg L−1 initial hydrogen peroxide concentration was approximately 95 and 98%, respectively. However, addition of hydrogen peroxide
over 50 mg L−1 inhibited the efficiency of the system. Addition of hydrogen peroxide to a UV/TiO2 system enhanced efficiency of removal of CODCr and color compared with no addition of hydrogen peroxide. This may be ascribed to capture electrons ejected from TiO2 and to the production of OH radicals. Application of the metal membrane in the UV/TiO2/H2O2 system enhanced the efficiency of removal of CODCr and color because of adsorption by the metal membrane surface and the production of OH radicals. By application of a metal
membrane with a nominal pore size of 0.5 μm, TiO2 particles were effectively separated from the treated water by metal membrane rejection. The photocatalytic metal membrane
had much less resistance than the humic acid, TiO2, and humic acid/TiO2 because of the degradation of humic acid by the photocatalytic reaction. 相似文献
934.
Jonghwan Lee Okgene Kim Jaeyeon Jung Kyunga Na Pilwoo Heo Jinho Hyun 《Colloids and surfaces. B, Biointerfaces》2009,72(2):173-180
We describe a simple method to fabricate an array of polystyrene microbeads (PS μbeads) conjugated with an elastin-like polypeptide (ELP) on a glass surface using a removable polymer template (RPT). A thin layer of adhesive was spun-cast on glass and cured by UV radiation. Micropatterns of an RPT were then transferred onto the surface by microcontact printing. The adhesion of PS μbeads on the surface depended on the adhesion performance of the adhesive layer, which could be adjusted by irradiation time. An array of PS μbeads conjugated with ELP was used for a smart immunoassay of prostate-specific antigen (PSA), a cancer marker. By controlling the phase transition of ELP molecules, PSA molecules were selectively adhered or released from the bead surface. The selective and reversible binding of PSA molecules on the bead surface was characterized with fluorescence microscopy. 相似文献
935.
936.
937.
Development of a Sensitive LC Assay with Fluorescence Detection for the Determination of Zearalenone in Rat Serum 总被引:1,自引:0,他引:1
Beom Soo Shin Seok Hyun Hong Hyoung Jun Kim Hae-Seong Yoon Do Jung Kim Sang Wook Hwang Jong Bong Lee Sun Dong Yoo 《Chromatographia》2009,69(3-4):295-299
A simple and sensitive liquid chromatographic assay with fluorescence detection assay was developed for the determination of zearalenone levels in rat serum. The assay utilized a single liquid–liquid extraction with t-butyl methyl ether and isocratic elution using a mobile phase consisting of acetonitrile and 0.1% triethylamine in distilled water (pH = 6) (50:50, v/v). Linearity was observed over a concentration range from 10 to 1,000 ng mL?1 (r = 0.9995), with the limit of quantification at 10 ng mL?1 with 100 μL of rat serum. The validated assay was applied to a pharmacokinetic study in rats. 相似文献
938.
Reliable determination of arsine (AsH3) in gases is of great importance due to stringent regulations associated with health, safety and environmental issues. It is, however, challenging for an analyst to determine trace airborne arsine concentrations without specifically designed collection procedures using adsorption, desorption, dissolution or impinging techniques. To circumvent such technical barrier, we have newly developed a direct analytical method, characterized by introduction of an arsine gas sample into stable plasma stream, followed by gas-phase oxidation of arsine with molecular oxygen in a dynamic reaction cell (DRC) equipped within the inductively coupled plasma-mass spectrometry (ICP/MS) system, followed by subsequent detection of AsO+ ion. This preliminary work used trace arsine concentrations (161 μg m−3, 322 μg m−3, and 645 μg m−3) gravimetrically prepared in N2 balance. The proposed method was optimized for the important experimental parameters such as the flow rates of the reaction gas, the arsine sample, and the carrier gas. This method was then validated by demonstrating good figure-of-merits including the low limit of detection (0.10 μg m−3), good linearity (r2 > 0.9915), low measurement uncertainty (0.66%), and high speed of analysis (<6 min). The proposed method is expected to be potentially applicable to the determination of arsine in real workplace air after appropriate modifications are made. 相似文献
939.
We report a method for the quantitative analysis of human serum leptin, which is a protein hormone associated with obesity, using a nanoarray protein chip based on a single-molecule sandwich immunoassay. The nanoarray patterning of a biotin-probe with a spot diameter of 150 nm on a self-assembled monolayer functionalized by MPTMS on a glass substrate was successfully accomplished using atomic force microscopy (AFM)-based dip-pen nanolithography (DPN). Unlabeled leptin protein molecules in human serum were detected based on the sandwich fluorescence immunoassay by total internal reflection fluorescence microscopy (TIRFM). The linear regression equation for leptin in the range of 100 zM-400 aM was determined to be y = 456.35x + 80,382 (R = 0.9901). The accuracy and sensitivity of the chip assay were clinically validated by comparing the leptin level in adult serum obtained by this method with those measured using the enzyme-linked immunosorbent assay (ELISA) performed with the same leptin standards and serum samples. In contrast to conventional ELISA techniques, the proposed chip methodology exhibited the advantages of ultra-sensitivity, a smaller sample volume and faster analysis time. 相似文献
940.
F. Casetti W. Jung U. Wlfle J. Reuter K. Neumann B. Gilb A. Whling S. Wagner I. Merfort C.M. Schempp 《Journal of photochemistry and photobiology. B, Biology》2009,96(3):260-265
We investigated the skin tolerance and anti-inflammatory potential of a nanoparticular solubilisate of a luteolin-rich Reseda extract (s-RE) in two independent studies in vivo. Reseda luteola extract containing 40% flavonoids was solubilized with polysorbate, resulting in product micelles with a diameter of 10 (±1.5) nm. Standardized inflammation was induced by irradiating test areas on the back of healthy volunteers with defined doses of ultraviolet B (UVB). In the first study different concentrations of s-RE were tested in 10 volunteers to evaluate dose-dependency of anti-inflammatory effects of s-RE. In the second randomized, double-blind, placebo-controlled study a defined concentration of s-RE (2.5% w/w) was tested in 40 volunteers in comparison to the vehicle (glycerol) and hydrocortisone (1% w/w). s-RE dose-dependently reduced UVB-induced erythema when applied 30 min before irradiation. To a lesser extent, topical application of s-RE after irradiation also reduced UVB-induced erythema. s-RE was as effective as hydrocortisone, whereas the vehicle had no effect. Occlusive application of s-RE on non-irradiated test sites did not cause any skin irritation. Due to excellent skin tolerance combined with potent anti-inflammatory properties s-RE bears potential especially for the prevention but also for the treatment of inflammatory skin conditions such as UV-induced erythema. 相似文献