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排序方式: 共有436条查询结果,搜索用时 23 毫秒
91.
Rana Ahmed Youness Reem Amr Assal Shahira Mohamed Ezzat Mohamed Zakaria Gad Amira Abdel Motaal 《Natural product research》2020,34(10):1475-1480
AbstractThis study focused on studying the impact of flavonoids isolated from Cleome droserifolia on HCC cell lines and to further unveil their possible impact on TP53 and its downstream tumor suppressor miRNAs. Three flavonol glycosides were isolated from C. droserifolia namely, Isorhamnetin-3-O-β-D-glucoside (1), Quercetin-3`-methoxy-3-O-(4``-acetylrhamnoside)-7-O-α-rhamnoside (2), and Kaempferol-4`-methoxy-3,7-O-dirhamnoside (3). They showed a concentration and time dependent reduction in cellular viability and anchorage-independent growth of HCC cells. Moreover, they exhibited a decrease in the migrating capacity of HepG2 cells in a pattern similar to positive control cells. (2) Showed the most potent effects in halting HCC tumorigenic activity (IC50=36?±?1.70?µM) and a repression of the cellular proliferation rate of HepG2 cells. Restoration of TP53 and its downstream tumor suppressor miRNAs; miR-15a, miR-16, miR-34a by (2) was observed. Moreover, attenuation of (2) mediated actions was shown upon using anti-miR-15a and anti-miR-16. To conclude, this study crystallizes a novel role of C. droserifolia in harnessing HCC progression in-vitro with a possible contribution of TP53/miR-15a/miR-16. 相似文献
92.
Abdel-Galil E. Amr Mohamed I. Hegab Alhusain A. Ibrahiem Mohamed M. Abdulla 《Monatshefte für Chemie / Chemical Monthly》2003,147(5):1395-1409
A series of 2,6-disubstituted pyridine ester derivatives and the corresponding amides were prepared. The esters were hydrolysed to the sodium salts, which were treated with acetic anhydride to afford oxazinone derivatives. These were treated with ammonium acetate to afford 2-methylpyrimidinone derivatives, which were methylated to yield 2,3-dimethylpyrimidinone derivatives. In addition, they were reacted with aniline or hydrazine hydrate to give 3-phenyl- or 3-aminopyrimidinone derivatives. The latter reacted with 2-thiophenecarbaldehyde or phthalic anhydride to afford the corresponding Schiffs base and imide derivatives. Diazotization of amides gave thienotriazinone derivatives, which were treated with ethyl iodide to afford the corresponding 3-ethyltriazinone derivatives. Also, they were reacted with phenyl isothiocyanate to give the corresponding thiopyrimidinone derivatives, which were alkylated with ethyl iodide or chloroacetic acid to afford the corresponding thioethyl- or thioglycolic acid pyrimidinone derivatives.The pharmacological screening showed that many of these obtained compounds have good analgesic, anticonvulsant, and antiparkinsonian activities comparable to Voltarene®, Carbamazepine®, and Benzotropene® as reference drugs. 相似文献
93.
Dark-field light microscopy is widely employed to visualize colloidal particles much smaller than the light wavelength used. In the captured images, the colloidal particles appear, against a dark background, as bright "specks" much larger than the geometrical size of the particles. To verify whether the "specks" are for individual particles or clusters of particles, experiments are performed which used low bulk concentrations of five suspensions of monodispersed particles (approximately 0.3 microm in diameter) and a dark-field video microscopic system with an optical resolution of approximately 0.5 microm to count the particles after they all have deposited onto the inner surfaces of a parallel-plate glass channel. The average size and the size distribution of the particles are also determined at the end of each experiment. The results confirmed that the visualized "specks" are for individual particles. The measured and prepared particle bulk concentrations in the five experiments closely matched, to within +/-5%, and the measured average size of the particles and their size distribution at the end of the five experiments were in agreement with the known values. 相似文献
94.
Ahmed F. A. Shalaby Mohamed M. Abdulla Abd El Galil E. Amr Azza A. Hussain 《Monatshefte für Chemie / Chemical Monthly》2007,138(10):1019-1027
Summary. A series of substituted heterocyclic systems were prepared from N1-[4-(4-fluorocinnamoyl)phenyl]-5-chloro-2-methoxybenzamide, which was prepared from the corresponding 5-chloroanisic acid
(2-methoxy-4-chlorobenzoic acid) as starting material. Treating of the cinnamoyl derivative with hydrazine hydrate in dioxane
afforded a pyrazoline, which was reacted with morpholine and paraformaldehyde to give the N-substituted pyrazoline. Acylation of pyrazoline with acetyl chloride in dioxane afforded the N-acetyl analogue. Also, the cinamoyl derivative was reacted with methylhydrazine, phenylhydrazine, or ethyl cyanoacetate to
yield the corresponding N-methyl-, N-phenylpyrazoline, pyrane, and pyridone derivatives. Condensation of the cinnamoyl derivative with cyanothioacetamide gave
the pyridinethione derivative, which was treated with ethyl chloroacetate affording the ethyl carboxylate derivative. Also,
it was reacted with malononitrile or ethyl acetoacetae to give the cyano amino analougues and ethyl carboxylate, which was
reacted with methylhydrazine to give the (indazolyl)phenyl derivative. On the other hand, reaction of cinnamoyl derivative
with acetyl acetone afforded the cyclohexenyl derivative, which was reacted with hydrazine hydrate to give the [methylindazolyl]phenyl
derivative. Condensation of the cinnamoyl derivative with guanidine hydrochloride or thiourea afforded the aminopyrimidine
derivative and thioxopyrimidine. The latter was condensed with chloroacetic acid to yield a thiazolopyrimidine, which was
condensed with 2-thiophenealdehyde to yield the arylmethylene derivative, however, it was also prepared directly from thiopyrimidine
by the action of chloroacetic acid, 2-thiophenealdehyde, and anhydrous sodium acetate. The pharmacological screening showed
that many of these compounds have good anti-arrhythmic activity and low toxicity. 相似文献
95.
Saber Chatti Hans R. Kricheldorf Gert Schwarz 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3616-3628
Isosorbide and equimolar amounts of various diols were polycondensed with diphosgene and pyridine. Bisphenol A, 3,3′‐dimethyl bisphenol A, bisphenol C, 1,3‐bis(4‐hydroxybenzoyloxy)propane, and 1,4‐cyclohexane diol were used as comonomers. The compositions were determined by 1H NMR spectroscopy; the random sequences were characterized by 13C NMR spectroscopy. For the high‐molar‐mass copolycarbonates of bisphenol A, 3,3′‐dimethyl bisphenol A, and bisphenol C, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry proved that the chain growth was mainly limited by cyclization. Copolycarbonates with alternating sequences were obtained by the polycondensation of bisphenol A with isosorbide bischloroformiate or from isosorbide and bisphenol A bischloroformiate. In these cases, large amounts of cyclic oligo‐ and polycarbonates were also formed. The glass‐transition temperatures were determined by differential scanning calorimetry measurements. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3616–3628, 2006 相似文献
96.
We give in this paper a short semantical proof of the strong normalization for full propositional classical natural deduction.
This proof is an adaptation of reducibility candidates introduced by J.-Y. Girard and simplified to the classical case by
M. Parigot. 相似文献
97.
In continuation to our search for new heterocyclic systems based antiinflammatories, the suggestion and synthesis of some
pyrimidines, thienopyrimidines, and their derivatives, were herein realized. The pharmacological screening showed that many
of these compounds have good antiinflammatory activity. The structure assignments of the new compounds are based on chemical
and spectroscopic evidence. The detailed synthesis, spectroscopic data, and pharmacological properties are reported.
Correspondence: Abd El-Galil Elsayed Amr, National Research Center, Organic Chemistry Department, Cairo, Dokki, Egypt. 相似文献
98.
The uptake behavior of porous silica modified with N‐propylsalicylaldimine (IE11) for Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) metal ions were studied. The Log kd values were found to be within the range 2.19–5.16 depending on pH and time of stirring. IE11 was used in the separation and preconcentration of Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) from some natural water samples. The data were compared with those obtained by the solvent extraction method (APDC/MIBK). The method was found to be accurate and precise and not subject to random error. 相似文献
99.
Herdic PC Houston BH Marcus MH Williams EG Baz AM 《The Journal of the Acoustical Society of America》2005,117(6):3667-3678
The surface and interior response of a Cessna Citation fuselage section under three different forcing functions (10-1000 Hz) is evaluated through spatially dense scanning measurements. Spatial Fourier analysis reveals that a point force applied to the stiffener grid provides a rich wavenumber response over a broad frequency range. The surface motion data show global structural modes (approximately < 150 Hz), superposition of global and local intrapanel responses (approximately 150-450 Hz), and intrapanel motion alone (approximately > 450 Hz). Some evidence of Bloch wave motion is observed, revealing classical stop/pass bands associated with stiffener periodicity. The interior response (approximately < 150 Hz) is dominated by global structural modes that force the interior cavity. Local intrapanel responses (approximately > 150 Hz) of the fuselage provide a broadband volume velocity source that strongly excites a high density of interior modes. Mode coupling between the structural response and the interior modes appears to be negligible due to a lack of frequency proximity and mismatches in the spatial distribution. A high degree-of-freedom finite element model of the fuselage section was developed as a predictive tool. The calculated response is in good agreement with the experimental result, yielding a general model development methodology for accurate prediction of structures with moderate to high complexity. 相似文献
100.
The program described provides simultaneously digital control of a high-resolution spectrofluorimeter, acquisition of analog signals and data storage, and contains graphics processing to visualize spectra. Automatic evaluation software, which evaluates peak heights and calculates concentrations is included. The program runs on an IBM PC-AT2 (or compatible) equipped with interface cards; it is composed of distinct modules which are obtained through a menu. The system has been applied to the determination of 13 polynuclear aromatic hydrocarbons (PAHs); it offers high selectivity, excellent detection limits, and rapidity of data acquisition. Results obtained for 9 PAHs in a standard urban dust (SRM-1649) were satisfactory. 相似文献