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301.
Ibrahim E. El Aassy Mohamed M. El Galy Afaf A. Nada Mohamed G. El Feky Thanaa M. Abd El Maksoud Shadia M. Talaat Eman M. Ibrahim 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):173-184
The contents of natural radionuclides in various types of sedimentary rocks in Um Bogma Formation and base of El Hashash Formation
were determined by gamma-ray spectrometry. Three types of lower Carboniferous sedimentary rocks were investigated; sandstone
(El Hashash Formation), dolostone and argillaceous sediments (Um Bogma Formation). The alteration processes are dolomitization,
dedolomitization, karstification and lateritization. The specific radioactivity of 238U, 226Ra, 232Th and 40K determined in different samples, indicate that 238U and its decay products contribute primarily to the high natural radioactivity of rocks. The maximum concentration of 238U reached up to 2129.36 ppm in argillaceous sediments. The average concentrations of determined radionuclides (238U, 226Ra, 232Th and 40K) are 8.34 ppm, 7.88 ppm, 4.68 ppm and 0.3%, respectively in sandstone. In dolostones the average concentrations are 418.69 ppm,
808.75 ppm, 3.14 ppm and 0.29%, respectively. For argillaceous sediments are 276.88 ppm, 419.49 ppm, 11.47 ppm and 0.93%,
respectively. The 238U/226Ra ratio in sandstone ranges between 0.89 and 1.25, while in dolostones and argillaceous sediments are 0.27–2.63 and 0.27–1.83,
respectively. These variations in the concentrations of radioelements and their ratios are due to the action of the alteration
processes affected these different sedimentary rocks in different times. Environmentally, the Raeq in dolostones and argillaceous sediments exceeds the permitted limits, while in the sandstone samples; it is within the permissible
levels. 相似文献
302.
Aaya Nassar Ibrahim M. Ibrahim Fatma G. Amin Merna Magdy Ahmed M. Elgharib Eman B. Azzam Filopateer Nasser Kirllos Yousry Israa M. Shamkh Samah M. Mahdy Abdo A. Elfiky 《Molecules (Basel, Switzerland)》2021,26(21)
A novel human coronavirus prompted considerable worry at the end of the year 2019. Now, it represents a significant global health and economic burden. The newly emerged coronavirus disease caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the primary reason for the COVID-19 global pandemic. According to recent global figures, COVID-19 has caused approximately 243.3 million illnesses and 4.9 million deaths. Several human cell receptors are involved in the virus identification of the host cells and entering them. Hence, understanding how the virus binds to host-cell receptors is crucial for developing antiviral treatments and vaccines. The current work aimed to determine the multiple host-cell receptors that bind with SARS-CoV-2 and other human coronaviruses for the purpose of cell entry. Extensive research is needed using neutralizing antibodies, natural chemicals, and therapeutic peptides to target those host-cell receptors in extremely susceptible individuals. More research is needed to map SARS-CoV-2 cell entry pathways in order to identify potential viral inhibitors. 相似文献
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305.
Eman Darweish Hoda M. Marzouk Yasmin M. Fayez Maya S. Eissa 《Journal of separation science》2023,46(1):2200695
Nowadays, Green Analytical Chemistry is widely applied to provide various analytical methods with eco-friendly procedures employing the least toxic, harmful reagents on humans and the environment without affecting the efficacy of the determination. Accordingly, two eco-friendly, accurate, and reliable high-performance thin-layer chromatography-densitometry and high-performance liquid chromatographic methods were established for the determination and separation of two antispasmodic drugs, namely phloroglucinol and trimethylphloroglucinol in their pure, combined dosage form along with phloroglucinol toxic impurity, 3,5-dichloroaniline. For high-performance thin-layer chromatography-densitometry, efficient separation was developed via utilizing the stationary phase of high-performance thin-layer chromatography silica gel 60 F254 plates and developing a system comprising of ethyl acetate-butanol-ammonia in the ratio of 8.0:2.0:0.2, by volume and scanning of the developed bands at 210.0 nm. The subsequent method is isocratic high-performance liquid chromatography with diode array detection in which separation was successively attained using XTerra RP-C18 (250 × 4.6 mm, 5 μm) column as stationary phase and methanol-10.0 mM phosphate buffer, pH 3.7 ± 0.1 as mobile phase in the ratio of 75.0:25.0, v/v at flow rate 1.0 ml/min and scanning at 220.0 nm. The developed liquid chromatography methods were validated according to the International Council for Harmonization guidelines, and all results acknowledged their efficacy. Additionally, the proposed methods worked well for assessing the cited drugs in binary combined commercially available pharmaceutical formulation. The greenness profile of the present methods was assessed and estimated using various assessment tools, namely; Green Analytical Procedure Index, analytical eco-scale method, National Environmental Method Index in addition to Analytical GREEnness tool to evaluate the greenness of the provided methods with a statistical comparison between them to assess the more green ones. 相似文献
306.
Khushbakhat Khan Muhammad Saeed Sameer A. Awad Muhammad Younas Khan Eman M. Khalaf Muhammad Saleh Zaman Vaneeza Aiman Tasmia Irshad Hadia Ahsan 《中国化学会会志》2023,70(1):46-57
The recent study enlightens the synthesis and characterization of zirconia (ZrO2), Fe-doped ZrO2 (Fe@ZrO2), and Ni-doped ZrO2 (Ni@ZrO2) catalysts having new-fangled morphology with tuned band gap as photocatalysts for degradation of textile wastewater dyes methylene blue (MB), malachite green (MG), and their mixtures. SEM imaging of Fe@ZrO2 and Ni@ZrO2 is interestingly varied from ZrO2 as well as doping of transition metals greatly affects the morphology of composites. The optimization study depicts that the pH, time (min) and catalyst amount (g) have a direct relation with degradation efficiency, while the dye concentration (mg/L) has an indirect relation as well. The photocatalytic studies depict that the degradation of MB and MG follows oxidation pathway via hydroxyl radicals (OH•) and holes. Reusability of catalysts corresponds to a little decrease in degradation efficiency in the first two cycles and decreases to about ∼10% (Ni@ZrO2) and ∼12% (Fe@ZrO2) in next three cycles. 相似文献
307.
Zaghloul E. Kandeel Kamal M. Dawood Eman A. Ragab Ahmad M. Farag 《Heteroatom Chemistry》2002,13(3):248-251
The cyanothioacetanilide derivative 3 reacted readily with either α‐halocarbonyl compounds 4 or α‐halodicarbonyl compounds 8 to afford the same thiophene derivatives 6 . Compound 3 also reacted with hydrazonoyl chlorides 12 and 16 and furnished the new polyheterocyles 14 and 17 , respectively. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:248–251, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10024 相似文献