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991.
Payam Sadeghi Shabestari Zahra Rostami Viet-Thanh Pham Fawaz E. Alsaadi Tasawar Hayat 《理论物理通讯》2019,71(10):1241-1245
Parkinson's and Huntington's diseases are two of the most common neurodegenerative disorders.Tremor, muscle stiffness, and slowness of movement are symptoms of Parkinson's disease. The symptoms of Huntington's disease are severe reduction in muscle control, emotional disturbance, and pathological disorders in brain cells.These diseases are caused by destruction of the cells that secrete a substance called dopamine. In this paper,a new discrete chaotic system is introduced,which can mimic the brain's behavior for neurodegenerative diseases such as Parkinson,Huntington, and Hypokinesia. This system is described based on the similarity between the brain's behavior in normal and abnormal conditions and the chaotic systems. Bifurcation analysis is carried out with respect to different parameters, providing full spectrum of the behavior for different parameter values.Our results can be used to mathematically study the mechanisms behind these diseases. 相似文献
992.
In this study, a magnetically reusable artificial metalloenzyme has been constructed by co-immobilization of palladium nanoparticles as a strong oxidizing catalyst and laccase as an oxygen-activating enzyme into the cavities of magnetic mesocellular foams silica (Pd-Laccase@MMCF). The combination of Pd-Laccase@MMCF and hydroquinone (HQ) act as electron-transfer mediator system and make stepwise electron transfer from substrate to molecular oxygen. This catalyst system was used for the aerobic (i) oxidation of alcohols to the corresponding carbonyl compounds and (ii) dehydrogenation of 2-substituted-2,3-dihydroquinazolin-4(1H)-ones in phosphate buffer (0.1 M, pH 4.5, 4 mL)/THF (4%, 1 mL) as solvent under mild conditions. The co-immobilization of both laccase and Pd onto high surface area mesoporous support, high catalytic activity and magnetically separable and reusable make the present catalyst system superior to other currently available electron-transfer mediator systems. 相似文献
993.
A new heterogeneous cobalt catalyst has been synthesized by immobilizing Co species onto a nitrogen-rich porous organic polymer (Co@imine-POP). The heterogeneous catalyst synthesized was efficient in Heck and Sonogashira cross-coupling reactions in green media under mild reaction conditions without inert air and phase transfer agents. This phosphine-, copper-, and palladium-free catalyst was stable under the reaction conditions and could be reused for at least eight successive runs without a discernible decrease in its catalytic activity. 相似文献
994.
The three-component reaction of phenacyl bromide, dimethyl acetylenedicarboxylate and pyridine is catalyzed by layered double hydroxides@poly(p-phenylenediamine) (LDHs@PpPDA), in a one-pot reaction, in order to give the corresponding indolizines in excellent yields. 相似文献
995.
In this study, Fe3O4 nanoparticles were functionalized with cellulose, and then hybridized with cobalt (II)-based metal-organic framework (Co-MOF) containing carboxylate and imidazole functionalities. FTIR, XRD, FE-SEM, TEM, BET, EDX, VSM and STA analyses were used to characterize the synthesized samples. The resultant Fe3O4/cellulose/Co-MOF nanocomposite was applied efficiently as a powerful and economic heterogeneous catalyst in the condensation of a variety of different aromatic aldehydes with malononitrile under solvent-free conditions at room temperature for 10 min and offered the corresponding coupling products in high yields. The catalyst could be straightforwardly separated by a magnet from the reaction mixture and reused without a noteworthy drop in catalytic activity at least five times. The use of Fe3O4/cellulose/Co-MOF catalyst outcomes under mild reaction conditions in very short reaction time, outstanding catalytic activity, high recyclability and an easy work-up process for Knoevenagel condensation. 相似文献
996.
Zahra Karamshahi Ramin Ghorbani-Vaghei Hassan Keypour Mohammad Taher Rezaei 《应用有机金属化学》2020,34(9):e5737
Recent studies about innovations in GO/N-Ligand-Cu Nano-Composites have been done. Graphene-Oxide is improved with N1,N3-bis (pyridin-2-ylmethyl)propane-1,3-diamine and after that is matched with copper (Cu). The chemical composition and the structure of the catalyst were analyzed by TGA/DTG, EDX, XRD, FT-IR, TEM, and SEM. The results demonstrated that GO/N-Ligand-Cu was able to catalyze the chromeno[2,3-b]pyridine compounds to obtain high yields in short reaction time. The results of the present work are hoped to assist the growth of a new class of heterogeneous catalysts as the high-function candidate for industrial applications. 相似文献
997.
Fatma Zahra Belkacemi Mounia Merabet-Khelassi Louisa Aribi-Zouioueche Olivier Riant 《Tetrahedron: Asymmetry》2017,28(11):1644-1650
Candida antarctica lipase proved to be a particularly efficient lipase for the resolution of racemic 2-arylcyclohexyl acetate in hydrolysis reaction with Na2CO3 in an organic medium. The (1R,2S)-trans-2-arylcyclohexanols 2a–2d were obtained with high ee values (up to >99%) and the selectivity reached E > 200. The influence of the enol ester and the solvent on (±)-trans-2-arylcyclohexanol in the CAL-B catalyzed acylation was also studied and compared with the deacylation. The CAL-B exhibits a better affinity for the alkaline hydrolysis reaction compared with acylation with the enol esters in the same organic solvents. The best conditions were applied to resolve a stereoisomeric mixture cis/trans-2-phenyl-1-cyclohexanol and its corresponding acetate by acylation and deacylation. The obtained results show a highly enantio- and diastereoselectivity of the CAL-B during the acylation and the deacylation in favor of the trans-(R)-enantiomer product. The resolution of a mixture of cis/trans-2-arylcyclohexanols was an easy, convenient approach to provide only one stereoisomer of a mixture of four with high enantiomeric excess. 相似文献
998.
999.
1000.
P. Brun J. Casanova J. Hatem J. P. Zahra B. Waegell 《Magnetic resonance in chemistry : MRC》1979,12(9):537-541
The 13C chemical shift data of some tricyclic derivatives prepared by carbene addition to bicyclo-alkenes are presented and compared with the shifts observed in the parent olefins. The shielding induced at the C-7 atom can be used to determine the stereochemistry of the carbene addition. 相似文献