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排序方式: 共有199条查询结果,搜索用时 15 毫秒
81.
Mamdouh A. Hassan Ragab F. Fandy Tark M. El‐Amine 《Journal of heterocyclic chemistry》2001,38(1):179-183
Treatment of 2‐aryl‐3,6‐bis(arylamino)‐1,4‐benzoquinones 2a‐h with different acid chlorides, namely acetyl, phenylacetyl and chloroacetyl chloride yields 3a,7a‐dihydropyrrolo[2,3‐f]indole‐2,6‐dione 3, 5‐(N‐phenylacetylarylamino)‐3‐phenylindole‐2,6‐dione 4 and 3‐chloro‐5‐(N‐chloroacetylarylamino)indole‐2,6‐dione 5 respectively. Stirring 2‐aryl‐1,4‐benzoquinones ( 1 ) with ethylenediamine and/or o‐phenyl‐enediamine in methylene chloride gives pyrazino[2,3‐g]quinoxalines derivative 6 and/or tetrapentacene derivative 7 respectively. The products 5‐aryl‐ and 6‐aryl‐1/H‐indazole‐4,7‐diones 8 and 9 were obtained in the 1,3‐dipolar cycloaddition of diazomethane to ( 1 ). 相似文献
82.
3‐(Pyrazol‐3‐yl)‐3‐oxo‐propanenitrile derivative reacts with several nitrogen nucleophiles to give bipyrazole, pyrazolyloxazole, and pyrazolylpyrimidine derivatives. The structures of the products were confirmed on the basis of their elemental and spectral analyses. 相似文献
83.
Korany A. Ali Heba S. Abdalghfar Khaled Mahmoud Eman A. Ragab 《Journal of heterocyclic chemistry》2013,50(5):1157-1164
The versatile multifunctional unreported pyridine‐2,6‐bis(2‐cyano‐N‐phenyl‐3‐oxopropanethioamide) ( 3 ) was prepared starting from pyridine‐2,6‐bis‐(3‐oxopropanenitrile) ( 1 ). Several new series of polysubstituted thiophenes and 1,3,4‐thiadiazoles incorporating 2,6‐pyridine moiety were efficiently synthesized. The newly synthesized compounds were evaluated for their in vitro anticancer activity against human cancer cell lines: hepatocellular liver carcinoma (HEPG2) and Caucasian breast adenocarcinoma (MCF‐7). Some of the newly synthesized compounds exhibited better activity than doxorubicin as a reference drug. 相似文献
84.
Korany A. Ali Eman A. Ragab Grzegorz Mlostoń Małgorzata Celeda Anthony Linden Heinz Heimgartner 《Helvetica chimica acta》2013,96(4):633-643
On treatment of 3‐amino‐5‐aryl‐1H‐pyrazoles 1 with dialkyl dicyanofumarates (=(E)‐but‐2‐enedioates) 4 in boiling 1,2‐dichloroethane, two competitive reactions occurred leading to 3‐aryl‐5‐cyano‐6,7‐dihydro‐6‐oxo‐1H‐pyrazolo[3,4‐b]pyridine‐4‐carboxylates 10 and 7‐amino‐2‐arylpyrazolo[1,5‐a]pyrimidine‐5,6‐dicarboxylates 11 . In DMF at room temperature, as well as at 100°, only compounds 10 were isolated. The formation of the major products of type 10 was rationalized via Michael addition of 1 as a C(4)‐nucleophile onto 4 , followed by HCN elimination and lactamization. On the other hand, the minor products 11 result from a Michael addition of 1 onto 4 via the NH2 group, and subsequent HCN elimination and cyclization. The structures of the products have been established by X‐ray crystallography. 相似文献
85.
A Facile Access to Some New Pyrazole, 1,3,4-Thiadiazole,and Thiophene Derivatives via β-Ketosulfones
Kamal M. Dawood Nabila A. Kheder Eman A. Ragab Sanaa N. Mohamed 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):330-339
3-Bromoacetyl-1,5-diphenyl-1H-pyrazole-4-carbonitrile (1) reacts with sodium benzenesulfinate to give the corresponding ketosulfone 2. Treatment of 2 with hydrazonoyl chlorides 3a,b gives the 3,3′-bipyrazoles 5a,b. Ketosulfone 2 reacts also with arylidenemalononitriles to give the pyrazolylpyridones 10a,b. The reaction of compound 2 with phenylisothiocyanate and potassium hydroxide and treating intermediate with hydrazonoyl halides and with α-haloketones gives the 1,3,4-thiadiazoles 18a–c and thiophenes 21a–f, respectively. 相似文献
86.
改性纳米TiO2固相光催化降解废弃聚氯乙烯 总被引:2,自引:1,他引:1
用偶联剂改性的纳米TiO2作催化剂,采用包埋法制备了一种新型的可光催化降解的纳米PVC-M-TiO2复合薄膜.在空气中紫外光照的条件下进行了该薄膜的光催化降解实验,并与以末改性的TiO2为催化剂的PVC-Un-TiO3复合薄膜的降解效率进行了比较,利用光照失重、傅立叶红外(FT-IR)光谱和扫描电子显微镜(SEM)等方法对光照前后复合薄膜进行厂分析表征.实验结果表明PVC-M-TiO2复合薄(TiO2质量百分含量为2%)膜在空气中能被有效的降解,连续光照480h后降解效率达到36.9%,明屁高于纯膜及未改性的PVC-Un-TiO2复合膜。 相似文献
87.
本文以光学耗散系统为范例,论证在满足细致平衡原理的条件下,可以与传统热力学相平行地发展一种“准热力学”模型。然后运用此模型系统而普遍地讨论了光学双稳系统的临界现象与相变。又借助Ginzburg-Landau模型处理了光学双稳性(第二类)临界点附近的涨落与关联。将平衡热力学的Landau相变理论推广到具有双稳性并远离热平衡的耗散系统。 相似文献
88.
The spectral and kinetic parameters of transient species generated in the irradiation of 6-ethoxy-2,2,4-trimethyl-8-nitro-1,2-dihydroquinoline
were examined by stationary and pulse photolysis in the solvents: heptane, acetonitrile, methanol, and ethanol. Upon excitation
of the long-wavelength absorption band (λex > 450 nm), a reversible photochemical reaction was revealed, and the spectral and kinetic parameters of three transient species
observed in the photolysis were characterized (λmax = 390, 400, and 420 nm (acetonitrile), k = 97, 500, and 2000 s−1, respectively). The absorption spectra and the rate constants of the decay of transient species are almost independent of
the medium polarity and the presence of oxygen in the system. The excited state generated during irradiation to the short-wavelength
absorption band (290 < λex < 350 nm) is inactive in the photochemical reaction and deactivates without the formation of transient species. The mechanism
of the reversible photochemical reaction is suggested, which involves the opening of the heterocycle N-C bond upon photoexcitation
of the long-wavelength absorption band and the thermal back reaction. 相似文献
89.
Mostafa M. Ghorab Fatma A. Ragab Helmy I. Heiba Walid M. Ghorab 《Journal of heterocyclic chemistry》2011,48(6):1269-1279
Quinoline derivatives posses many types of biological activities and have been reported to show significant anticancer activity. There is a variety of mechanisms for the anticancer activity and the most distinguished mechanism is the inhibition of vascular epithelial growth factor receptor tyrosine kinase (VEGFRTK). Novel quinoline derivatives 6 , 7a , 7b , 7c , 8 , 9 , 10 , 11 , 12 and pyrimido[4,5‐b]quinoline derivatives 16 , 17 , 18 , 19 , 20 are reported herein. All the newly synthesized compounds were evaluated for their in vitro anticancer activity against human breast cancer cell line (MCF7) in which VEGFR is highly expressed. Compounds 6 and 7 with IC50 values of 8.5 μM and 21.9 μM were the most active compounds and exhibited cytotoxic activities higher than that of the reference drug doxorubicin (IC50= 32.02 μM). The most active compounds 6 and 7 were further evaluated for their ability to enhance the cell killing effect of γ‐radiation. J. Heterocyclic Chem., (2011). 相似文献
90.
A combined experimental study and density functional theory calculations of fac‐[MnBr (CO)3L] complexes (L = 2‐(2′‐pyridyl)benzimidazole ligand, furnished with either morpholine (Lmorph) or phthalimido (Lphth) side‐chain) were performed using different spectral and analytical tools. The synthesized complexes released carbon monoxide upon the exposure to LED source light at 468 nm. Illumination of fac‐[MnBr (CO)3L] (10 μM) in the myoglobin solution (Mb) produced about 25 μM MbCO. The plateau of the CO release process is attained within 25 min. With the aid of time‐dependent density functional theory calculations, the observed lowest energy absorption transition at ~ 400 nm has a ground‐state composed of d (Mn)/π (pyridyl) and excited‐state of ligand π*‐orbitals forming MLCT/π‐π*. Natural population analyses of fac‐[MnBr (CO)3L] were carried out to get information about the strength of Mn–CO bonds, electronic arrangment and natural charge of manganese ion. 相似文献