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71.
Exploiting the 1,2,3‐Triazole Moiety to Generate Carbazole Molecular Architectures through Click Approach 下载免费PDF全文
Mohamed A. Ameen Kamal M. El‐Shaieb Asmaa H. Mohamed Fathy F. Abdel‐Latif 《Journal of heterocyclic chemistry》2015,52(6):1718-1722
Reaction of 3,6‐dichlorocarbazole with propargyl bromide in the presence of a basic medium gave an N‐propargylated carbazole. The latter compound was converted into molecular architectures containing 1,2,3‐triazole moiety through Cu(I)‐catalyzed 1,3‐cycloaddition reaction with different azides. Similarly, 2‐azidomethyl benzothiazole was cliched with N‐Boc‐protected N´‐propargyl glutamate to give the biomolecule 2‐triazolylmethyl product. 相似文献
72.
Aziz N. Abdel 《Fluid Dynamics》1993,28(5):736-738
The phenomenon of thermal relaxation of the gas bubbles in a fluid behind a shock front is analyzed. The approach to solving the problem of heat transfer between a gas bubble and a fluid developed by the author is used to obtain a solution describing the initial stage of bubble collapse behind the shock front.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 5, pp. 187–189, September–October, 1993. 相似文献
73.
Synthesis,Reactions, Characterization and Biological Evaluation of 2,3′‐Bipyridine Derivatives (III) 下载免费PDF全文
Fawzy A. Attaby Azza M. Abdel‐Fattah Labeeb M. Shaif Mohamed M. Elsayed 《Journal of heterocyclic chemistry》2014,51(4):927-936
1‐Pyridin‐3‐yl‐3‐(2‐thienyl of 2‐furyl)prop‐2‐en‐1‐ones 1a , 1b reacted with 2‐cyanoethanethioamide 2 to afford the corresponding 4‐(thiophen‐2‐yl or furan‐2‐yl)‐6‐sulfanyl‐2,3′‐bipyridine‐5‐carbonitriles 3a , 3b . The synthetic potentiality of compounds 3a , 3b were investigated in the present study via their reactions with several active halogen containing compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 5 , 5a , 5b . Our aim here is the synthesis of 4‐(2‐thienyl or 2‐furyl)‐6‐pyridin‐3‐ylthieno[2,3‐b]pyridin‐3‐amines 6a , 6b , 6c , 6d , 6e , 6g , 6h , 6i , 6j , 6k , 6l , 6m , 6n ,via 6‐(alkyl‐thio)‐4‐(2‐thienyl or 2‐furyl)‐2,3′‐bipyridine‐5‐carbonitriles 5a , 5b , 5c , 5d , 5e , 5i , 5j , 5k , 5l , 5m . The structures of all newly synthesized heterocyclic compounds were elucidated by considering the data of IR, 1H‐NMR, mass spectra, as well as that of elemental analyses. Anti‐cancer, anti‐Alzheimer, and anti‐COX‐2 activities were investigated for all the newly synthesized heterocyclic compounds. 相似文献
74.
Synthesis of Novel Modified Guanidines: Reaction of Dicyandiamide with Amino Acids,Amides, and Amines in Aqueous Medium 下载免费PDF全文
Ahmed M. Soliman Shaaban K. Mohamed Mahmoud. Abd El Aleem. Ali. Ali. El‐Remaily H. Abdel‐Ghany 《Journal of heterocyclic chemistry》2014,51(5):1322-1326
Reaction of dicyandiamide with series of amino acids afforded guanidinyl pyrazolones 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , respectively. Although reaction of dicyandiamide with urea, acetamide, bezamide, allantion, p‐aminobenzoic acid, sulphanilic acid, and adenine gave biguanides 20 , 21 , 22 , 23 , 24 , 25 , 26 , respectively. All compounds have been characterized on the basis of IR and 1H‐NMR. 相似文献
75.
Ahmed M. M. Soliman Mahmoud. Abd El‐Aleem. Ali. Ali. El‐Remaily Adel. A. Sultan Hossam. Abdel‐Ghany 《Journal of heterocyclic chemistry》2014,51(5):1476-1481
5‐Amino‐3‐anilino‐1H‐pyrazole‐4‐carbonitrile 1 was alkylated with various halo reagents under phase transfer conditions to give the corresponding imidazopyrazole derivatives 2a , 2b , 2c , 3 , 4 , 5 , 6 . Pyrazolo[1,5‐a] pyrimidine derivatives 11 , 12 , 13 , 14 were prepared by treating compound 1 with different dicarbonyl reagents, namely, diethymalonate, ethyl 3‐oxo‐3‐phenylpropanoate, pentane‐2,4‐dione or ethyl 3‐oxobutanoate. 相似文献
76.
The aim of the present study was to determine the content of capsaicin and dihydrocapsaicin in Capsicum samples collected from city markets in Riyadh (Saudi Arabia), calculate their pungency in Scoville heat units (SHU) and evaluate the average daily intake of capsaicin for the population of Riyadh. The investigated samples consisted of hot chillies, red chillies, green chillies, green peppers, red peppers and yellow peppers. Extraction of capsaicinoids was done using ethanol as solvent, while high performance liquid chromatography (HPLC) was used for separation, identification and quantitation of the components. The limit of detection (LOD) of the method was 0.09 and 0.10 μg/g for capsaicin and dihydrocapsaicin, respectively, while the limit of quantification (LOQ) was 0.30 and 0.36 μg/g for capsaicin and dihydrocapsaicin, respectively. Hot chillies showed the highest concentration of capsaicin (4249.0 ± 190.3 μg/g) and the highest pungency level (67984.60 SHU), whereas green peppers had the lowest detected concentration (1.0 ± 0.9 μg/g); green peppers, red peppers and yellow peppers were non pungent. The mean consumption of peppers for Riyadh city population was determined to be 15.5 g/person/day while the daily capsaicin intake was 7.584 mg/person/day. 相似文献
77.
Alexei A. Gaivoronski Abdel Lisser Rafael Lopez Hu Xu 《Journal of Global Optimization》2011,49(3):397-413
This paper is dedicated to a study of different extensions of the classical knapsack problem to the case when different elements
of the problem formulation are subject to a degree of uncertainty described by random variables. This brings the knapsack
problem into the realm of stochastic programming. Two different model formulations are proposed, based on the introduction
of probability constraints. The first one is a static quadratic knapsack with a probability constraint on the capacity of
the knapsack. The second one is a two-stage quadratic knapsack model, with recourse, where we introduce a probability constraint
on the capacity of the knapsack in the second stage. As far as we know, this is the first time such a constraint has been
used in a two-stage model. The solution techniques are based on the semidefinite relaxations. This allows for solving large
instances, for which exact methods cannot be used. Numerical experiments on a set of randomly generated instances are discussed
below. 相似文献
78.
Ahmed Ahmed El‐Barbary Yehia Ahmed Hafiz Mohamed Shaker Abdel‐Wahed 《Journal of heterocyclic chemistry》2011,48(3):639-644
Thiation of 1 by LR gave the corresponding 3,5‐dithioxo derivative 2 and the trimer 3 . Methylation of 1 afforded the S‐methyl derivative 4 . Compound 1 was fused with 6‐bromo‐2‐phenyl‐benzo[1,3‐d]oxazin‐4‐one ( 5 ) and gave 6 . Condensation of 1 with some acid derivatives 7a , 7b , 7c , 7d and/or 8a , 8b , 8c yielded thiadiazolo‐triazine derivatives 9a , 9b , 9c , 9d and 10a , 10b , 10c . Compounds 9a , 9c and 10c were hydrolyzed to furnish 11a , 11b , 11c Acetylation of 14 afforded mono‐ and diacetyl‐derivatives 15 and 16 . Benzoylation of 14 afforded mono‐ and dibezoyl‐derivatives 17 and 18 . 14 with some aromatic aldehydes yielded 9a , 9b , 9c . Reacting 14 with phenyl (iso‐ and/or isothio‐) cyanate gave the urea derivatives 20a , 20b . Thiation of 14 with P4S10 furnished 21 . The newly synthesized compounds were tested as antimicrobial agents. J. Heterocyclic Chem., (2011) 相似文献
79.
This paper aims to evaluate a comprehensive numerical model based on solving rate equations of a thulium-doped silica-based fiber amplifier. The pump power and thulium-doped fiber (TDF) length for single-pass thulium-doped fiber amplifiers (TDFA) are theoretically optimized to achieve the optimum gain and noise figure (NF) at the center of S-band region. The 1064 nm pump is used to provide both ground-state and excited state absorptions for amplification in the S-band region. The theoretical result is in agreement with the published experimental result. 相似文献
80.
Abstract A simple and sensitive spectrophotometric method is described for the determination of buclizine hydrochloride in bulk and tablets form. The method is based on the formation of charge-transfer complex between buclizine, as n-donor, and iodine, as Δ acceptor, which measured spectrophotometrically at 295 and 355 nm. A Job's plot indicated a 1:1 complex between the drug and iodine and Beer's law was obeyed in a concentration range of 4–30 μg ml?1. A more detailed investigation of the complex was made with respect to its association constant and the free energy change. The method is simple and sensitive and has been applied successfully to the analysis of laboratory-made tablets without any interference from the tablet excipients. To validate the method, the results obtained were compared statistically with a newly developed uv-derivative spectrophotometric method. The charge-transfer method was favored due to its higher sensitivity, cheap coast and available equipments. 相似文献