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951.
952.
Wen-Juan Liang Qing-Yun Ma He-Zhong Jiang Jun Zhou Jie Pang You-Xing Zhao 《Chemistry of Natural Compounds》2012,47(6):935-939
A new oleane-type triterpene oligoglycoside, hederagenin 3-O-(3-O-acetyl-β-D-xylopyranosyl)-(1→3)-α-L-arabinopyranoside (2), together with four known compounds, hederagenin (1), hederagenin 3-O-(4-O-acetyl-α-L-arabinopyranosyl)-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside (3), hederagenin 3-O-α-L-arabinopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside (4), hederagenin 3-O-β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→4)-β-D-xylopyranoside (5), was isolated from the hull of Nephelium lappaceum. All the isolates were obtained from the hull of rambutan for the first time. 相似文献
953.
Identification of a new flavone glycoside from <Emphasis Type="Italic">Codonopsis nervosa</Emphasis>
Xian-li Zhou Qiang Fan Shuai Huang Cui-juan Wang You-song Wang 《Chemistry of Natural Compounds》2012,47(6):888-890
A new flavone glycoside, luteolin 7-O-[(6″′-caffeoyl)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranoside (1), was isolated from Codonopsis nervosa, along with three other known compounds, luteolin 7-O-β-D-glucopyranoside (2), luteolin 7-O-gentiobioside (3), and tangshenoside VI (4). Their structures were determined on the basis of 1D and 2D NMR, IR, and HR-ESI-MS. 相似文献
954.
Huanshun Yin Yunlei Zhou Tao Liu Tiantian Tang Shiyun Ai Lusheng Zhu 《Journal of Solid State Electrochemistry》2012,16(2):731-738
In this work, 3-aminopropyltriethoxysilane modified Fe3O4 nanoparticles (ATPS-Fe3O4) were used to modify glassy carbon electrode for aminopyrine determination. ATPS-Fe3O4 showed obviously catalytic activity and adsorptivity towards aminopyrine oxidation proven by the increased oxidation peak
current and the decreased oxidation peak potential. The best analytical response was obtained by immobilizing 8 μL 3 mg/mL
APTS-Fe3O4 dispersion with an accumulation time of 200 s at −0.2 V in 0.1 M phosphate buffer solution (pH 9.0). The oxidation peak current
of aminopyrine showed linear relationship with its concentration in the range from 0.5 to 100 and 100 to 1600 μM. The detection
limit was 0.1 μM (S/N = 3). The proposed method showed satisfactory repeatability and anti-interference ability. The fabricated
electrode was successfully applied to determine aminopyrine in pharmaceutical formulations. 相似文献
955.
Huanshun Yin Yunlei Zhou Ruixia Han Yanyan Qiu Shiyun Ai Lusheng Zhu 《Journal of Solid State Electrochemistry》2012,16(1):75-82
Hydroxylapatite (HAP)-modified glassy carbon electrode (GCE) was fabricated and used to investigate the electrochemical oxidation
behavior of 2,4-dinitrophenol (2,4-DNP) by cyclic voltammetry, differential pulse voltammetry, and chronocoulometry. The oxidation
peak current of 2,4-DNP at the modified electrode was obviously increased compared with the bare GCE, indicating that HAP
exhibits a remarkable enhancement effect on the electrochemical oxidation of 2,4-DNP. Based on this, a sensitive and simple
electrochemical method was proposed for the determination of 2,4-DNP. The effects of HAP concentration, accumulation time,
accumulation potential, pH, and scan rate were examined. Under optimal conditions, the oxidation peak current of 2,4-DNP was
proportional to its concentration in the range from 2.0 × 10−6 to 6.0 × 10−4 M with a correlation coefficient of 0.9987. The detection limit was 7.5 × 10−7 M (S/N = 3). The proposed method was further applied to determine 2,4-DNP in water samples with recoveries from 96.75% to 106.50%. 相似文献
956.
Liang Xue Fengqi Zhao Xiaoling Xing Zhiming Zhou Kai Wang Siyu Xu Jianhua Yi Rongzu Hu 《Journal of solution chemistry》2012,41(1):17-24
The enthalpies of dissolution of 1,2,3-triazole nitrate in water were measured using a RD496-2000 Calvet microcalorimeter
at four different temperatures under atmospheric pressure. Differential enthalpies (Δdif
H) and molar enthalpies (Δdiss
H) of dissolution were determined. The corresponding kinetic equations that describe the dissolution rate at the four experimental
temperatures are
\fracdadt / s - 1 = 10 - 3.75( 1 - a)0.96\frac{d\alpha}{dt} / \mathrm{s}^{ - 1} =10^{ - 3.75}( 1 - \alpha)^{0.96} (T=298.15 K),
\fracdadt /s - 1 = 10 - 3.73( 1 - a)1.00\frac{d\alpha}{dt} /\mathrm{s}^{ - 1} = 10^{ - 3.73}( 1 - \alpha)^{1.00} (T=303.15 K),
\fracdadt / s - 1 = 10 - 3.72( 1 - a)0.98\frac{d\alpha}{dt} / \mathrm{s}^{ - 1} = 10^{ - 3.72}( 1 - \alpha)^{0.98} (T=308.15 K) and
\fracdadt / s - 1 = 10 - 3.71( 1 -a)0.97\frac{d\alpha}{dt} / \mathrm{s}^{ - 1} = 10^{ - 3.71}( 1 -\alpha)^{0.97} (T=313.15 K). The determined values of the activation energy E and pre-exponential factor A for the dissolution process are 5.01 kJ⋅mol−1 and 10−2.87 s−1, respectively. 相似文献
957.
Li Y Zhao L Zhang H Jia J Lv L Zhou G Chai Y Zhang G 《Biomedical chromatography : BMC》2012,26(10):1234-1240
A sensitive and reliable liquid chromatography–mass spectrometry method has been developed and validated for simultaneous determination of cimifugin and prim‐O‐glucosylcimifugin in rat plasma after oral administration of Radix Saposhnikoviae (RS) extract, prim‐O‐glucosylcimifugin monomer solution and cimifugin monomer solution. Plasma samples were pretreated by protein precipitation with acetonitrile containing the internal standards puerarin and daidzein. LC separation was achieved on a Zorbax SB‐C18 column (150 × 4.6 mm i.d., 5 µm) with 0.1% formic acid in water and methanol by isocratic elution. The detection was carried out in select‐ion‐monitoring mode with a positive electrospray ionization interface. The fully validated method was successfully applied to the pharmacokinetic study of the analytes in rats. A bimodal phenomenon appeared in the concentration–time curve of prim‐O‐glucosylcimifugin and cimifugin after oral administration of RS extract. Prim‐O‐glucosylcimifugin mainly transformed to cimifugin when it was absorbed into blood. Both absorption and elimination of cimifugin after oral administration of RS were longer than after administration of single cimifugin. The pharmacokinetic parameters (AUC0–t, AUC0–∞ and t1/2) of prim‐O‐glucosylcimifugin and cimifugin by giving cimifugin monomer solution, prim‐O‐glucosylcimifugin monomer solution and RS extract had significant differences (P < 0.05). Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
958.
Sheng N Wei F Zhan W Cai Z Du S Zhou X Li F Hu Q 《Journal of separation science》2012,35(5-6):707-712
A unique stir bar coated with dummy molecularly imprinted polymers for bisphenol A was prepared by sol-gel technique. The scanning electron microscopic image of the coating presented a homogeneous surface with a thickness of about 57 ± 2.5 μm. The Fourier transform infrared spectrum of the coating proved the incorporating of dummy molecularly imprinted polymers with the sol-gel network. When used to extract bisphenol A from aqueous solution containing bisphenol A and its three analogs (4-tert-butylphenol, 4,4'-dihydroxybiphenyl, and 3,3',5,5'-tetrabromo-bisphenol A). Dummy molecularly imprinted polymers-coated stir bar showed better selectivity than the bars coated with polydimethylsiloxane or non-imprinted polymers. The extraction conditions including stirring speed, pH, and extraction time were optimized. After back extraction with methanol, the extracts were analyzed by high-performance liquid chromatography-fluorescence detection. The linear range was 0.0228-0.456 ng/mL with correlation coefficient of 0.9994 and the detection limit was about 5.70 × 10(-3) ng/mL based on three times ratio of signal-to-noise. The method was applied to the determination of trace bisphenol A in tap water. 相似文献
959.
Feng X Zhou W Li Y Ke H Tang J Clérac R Wang Y Su Z Wang E 《Inorganic chemistry》2012,51(5):2722-2724
The reactions of [CuTbL(Schiff)(H(2)O)(3)Cl(2)]Cl complexes with A- or B-type Anderson polyoxoanions lead to new polyoxometalate-supported 3d-4f heterometallic systems with single-molecule-magnet behavior. 相似文献
960.
Jiang W Zhou Y Zhang Y Xuan S Gong X 《Dalton transactions (Cambridge, England : 2003)》2012,41(15):4594-4601
Superparamagnetic Ag@Fe(3)O(4) nanospheres with core-shell nanostructures have been prepared by a facile one-pot method. The diameter of the as-synthesized nanospheres was about 200 nm and the core sizes were between 50 and 100 nm. By varying the concentrations, particles with tunable core size and total size are successfully achieved. Time dependent experiments were constructed to investigate the synthesis mechanism, which indicated that the present method corresponded to an Ostwald ripening progress. The BET area of the core-shell nanospheres is about 22.6 m(2)/g and this result indicates that the product shows a porous character. The saturated magnetization of the superparamagnetic Ag@Fe(3)O(4) nanospheres is 27.4 emu g(-1) at room temperature, which enables them to be recycled from the solution by simply applying a small magnet. Due to the unique nanostructure, these particles show high performance in catalytic reduction of 4-nitrophenol and can be used as reusable nanocatalysts. 相似文献