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31.
Lakovaara Matias Sirviö Juho Antti Ismail Mostafa Y. Liimatainen Henrikki Sliz Rafal 《Cellulose (London, England)》2021,28(9):5433-5447
Cellulose - In this work, deep eutectic solvent (DES) based on imidazole and triethylmethylammonium chloride was used as a reaction medium for the esterification of cellulose nanofiber (CNF) and... 相似文献
32.
Hayam M. Lotfy Mamdouh R. Rezk Adel M. Michael Mostafa A. Shehata 《Chromatographia》2013,76(3-4):187-194
Accurate, sensitive, and precise high performance thin layer chromatographic (HPTLC) methods were developed and validated for the determination of sumatriptan and zolmitriptan in presence of their degradation products. Sumatriptan was separated from its degradation products and analyzed on TLC silica gel 60 F254 plates using chloroform–ethyl acetate–methanol–ammonia (4:3:3:0.1, v/v) as a developing system followed by densitometric measurement of the bands at 228 nm. Zolmitriptan was determined using chloroform–ethyl acetate–methanol–ammonia (3:3:3:1, v/v) as a developing system followed by densitometric measurement at 222 nm. The methods were validated over a range of 0.5–4 μg/spot for sumatriptan and 0.5–3 μg/spot for zolmitriptan. The proposed methods were successfully applied for the determination of the studied drugs in bulk powder and in their pharmaceutical formulations. 相似文献
33.
Nasser Y. Mostafa Abdallah A. Shaltout Lachezar Radev Hassan M. Hassan 《Central European Journal of Chemistry》2013,11(2):140-150
The present work investigates surface biocompatibility of silicon-substituted calcium phosphate ceramics. Different silicon-substituted calcium phosphate ceramic bodies were prepared from co-precipitated powders by sintering at 1300°C. The in vitro bioactivity of the ceramics was assessed in simulated body fluid (SBF) at 37°C for periods up to 4 weeks. The changes in the surface morphology and composition were determined by scanning electron microscopy (SEM) coupled with electron probe microanalysis and energy dispersive spectrometer (EDX). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to observe the change in ionic concentration of SBF after removal of the samples. The bioactivity of the ceramics increased with an increasing silicate ion substitution in a systematic way. The surface of ceramics with 2.23% silicon substitution was partially covered with apatite layer after one week, while ceramics with 8.1% silicon substitution were completely covered with apatite in the first week. The porous microstructure of high-concentration Si-substituted ceramics helps the dissolution of surface ions and the leaching process. This allows SBF to reach supersaturation in a short time and accelerate the deposition of apatite layer. 相似文献
34.
Yousef Fazaeli Amir R. Jalilian Mostafa M. Amini Mohammadreza Aboudzadeh Shahzad Feizi Ali Rahiminezhad Kamran Yousefi 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):255-263
Cu-64 was produced via the 68Zn (p,αn)64Cu nuclear reaction (≈200 mCi, >95 % chemical yield at 180 μA for 1.1 h irradiation, (radionuclidic purity >96 %, copper-67 as impurity) followed by purification with amino functionalized nano magnetic oxide, Fe3O4 aiming to remove trace amount of heavy metal ions from aqueous media due to achieve ultra pure [64Cu] CuCl2 for labeling step. [64Cu] labeled 5,10,15,20-tetrakis(penta fluoro phenyl) porphyrin ([64Cu]-TFPP) was prepared using freshly prepared [64Cu] CuCl2 (Cu-64; T 1/2 = 12.7 h) and 5,10,15,20-tetrakis(penta fluoro phenyl)porphyrin (H2TFPP) for 60 min at 100 °C under reflux condition (radiochemical purity: >97 % ITLC, >98 % HPLC, specific activity: 14–16 GBq/mmol). Stability of the complex was checked in final formulation and human serum for 24 h. The partition coefficient was calculated for the compound (log P = 0.73). The biodistribution of the labeled compound in vital organs of wild-type rats was studied using scarification studies and PET imaging up in 2 and 4 h after injection. A detailed comparative pharmacokinetic study performed for 64Cu cation and [64Cu]-TFPP. The complex is mostly washed out from the circulation through kidneys and liver and can be an interesting tumor imaging/targeting agent due to high specific uptake and rapid excretion through the urinary tract. 相似文献
35.
Khalil MM Mohamed HA El-Medani SM Ramadan RM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(6):1341-1347
Reaction of Cr(CO)(6) with 2-(2'-pyridyl)benzimidazole (pbiH) under reduced pressure resulted in the formation of the dinuclear complex [Cr(2)(CO)(6)(pbiH)(2)]. Infra-red (IR) spectroscopy revealed the presence of terminal and bridge Cr-CO bonds. Interaction of M(CO)(6), M=Cr, Mo and W, with pbiH in the presence of 2,2'-bipyridine (bpy) gave the tetracarbonyl complexes [M(CO)(4)(pbiH)].bpy. Spectroscopic studies of the complexes indicated the presence of hydrogen bonding between the bpy nitrogen and the NH group of pbiH. Reactions of M(CO)(6) with pbiH in the presence of PPh(3) gave the tricarbonyl monosubstituted derivatives [M(CO)(3)(PPh(3))(pbiH)]. The spectroscopic studies of the complexes suggested the proposed structures. 相似文献
36.
Synthesis,characterization and catalytic performance of nanosized iron-cobalt catalysts for light olefins production 下载免费PDF全文
Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins (C2-C4) production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h-1 (H2/CO=2/1) at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction (XRD),thermal gravimetric analysis (TGA),differential scanning calorimetry (DSC),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. 相似文献
37.
Mohammadali Torbati Mir Ali Farajzadeh Mohammad Reza Afshar Mogaddam Mostafa Torbati 《Journal of separation science》2019,42(9):1768-1776
A homogeneous liquid‐liquid extraction performed in narrow tube coupled to in–syringe‐dispersive liquid‐liquid microextraction based on deep eutectic solvent has been developed for the extraction of six herbicides from tea samples. In this method, sodium chloride as a separation agent is filled into the narrow tube and the tea sample is placed on top of the salt. Then a mixture of deionized water and deep eutectic solvent (water miscible) is passed through the tube. In this procedure, the deep eutectic solvent is realized as tiny droplets in contact with salt. By passing the droplets from the tea layer placed on the salt layer, the analytes are extracted into them. After collecting the solvent as separated layer, it is mixed with another deep eutectic solvent (choline chloride/butyric acid) and the mixture is dispersed into deionized water placed in a syringe. After adding acetonitrile to break up the cloudy state, the collected organic phase is injected into gas chromatography‐mass spectrometry. Under optimal conditions, limits of detection and quantification in the ranges of 2.6–8.4 and 9.7–29 ng/kg, respectively, were obtained. The extraction recoveries and enrichment factors in the ranges of 70–89% and 350–445 were obtained, respectively. 相似文献
38.
Maghsoodlou Malek Taher Habibi-Khorassani Sayyed Mostafa Heydari Reza Hazeri Nourollah Sajadikhah Seyed Sajad Rostamizadeh Mohsen 《中国化学》2010,28(2):285-288
Synthesis of α‐amino phosphonates is described under solvent‐free conditions at 100°C from reaction between aldehydes and amines in the presence of trialkyl phosphites using Al(H2PO4)3 as an efficient and reusable heterogeneous catalyst. The advantages of this procedure are short reaction time, flexibility and having high to excellent yields. 相似文献
39.
Malek Taher Maghsoodlou Sayyed Mostafa Habibi-Khorassani Zahra Shahkarami Nariman Maleki Mohsen Rostamizadeh 《中国化学快报》2010,21(6):686-689
<正>2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) 4l-s produced from reaction between dimedone with various aldehydes in acetonitrile using ZnO as a catalyst;whereas in the presence of ZnO-acetyl chloride catalysts the reaction is limited to give only 1,8-dioxo-octahydroxanthenes 3a-k in very good yields. 相似文献
40.
Fariborz Momenbeik Mostafa Roosta Ali Akbar Nikoukar 《Journal of chromatography. A》2010,1217(24):3770-3773
An environmentally benign and simple method has been proposed for separation and determination of fat-soluble vitamins using isocratic microemulsion liquid chromatography. Optimization of parameters affecting the separation selectivity and efficiency including surfactant concentration, percent of cosurfactant (1-butanol), and percent of organic oily solvent (diethyl ether), temperature and pH were performed simultaneously using genetic algorithm method. A new software package, MLR-GA, was developed for this purpose. The results indicated that 73.6 mM sodium dodecyl sulfate, 13.64% (v/v) 1-butanol, 0.48% (v/v) diethyl ether, column temperature of 32.5 °C and 0.02 M phosphate buffer of pH 6.99 are the best conditions for separation of fat-soluble vitamins. At the optimized conditions, the calibration plots for the vitamins were obtained and detection limits (1.06–3.69 μg mL−1), accuracy (recoveries > 94.3), precision (RSD < 3.96) and linearity (0.01–10 mg mL−1) were estimated. Finally, the amount of vitamins in multivitamin syrup and a sample of fish oil capsule were determined. The results showed a good agreement with those reported by manufactures. 相似文献