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961.
962.
An alternative method has been developed for the anomeric deacetylation of fully acetylated carbohydrate derivatives using zinc acetate dihydrate as a catalyst in methanol under mild conditions. The experimental simplicity, low cost, acceptable yield, use of a readily handled acidic catalyst, and the environmentally benign nature are some of the advantages of this method. 相似文献
963.
The present investigation is emphasized on the effect of various combustion agents on the crystal properties, surface microstructure, and oxygen ion conductivity of 20% mole-Sm doped ceria (Ce0.80Sm0.20O1.90/SDC20) ceramics as solid electrolyte for IT-SOFCs. The most widely used combustion agents for engineering ceramic production as ethylene glycol, diethylene glycol, triethylene glycol, L-alanine, L-valine, glycine, citric acid monohydrate, urea, and EDTA-citric acid were compared in terms of SDC20 properties. X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and electrochemical impedance spectroscopy (EIS) were used to determine the microstructure properties, crystal structure and ionic conductivity of SDC20 powder. XRD pattern of the ceramics revealed the formation of single-phase fluorite structure. According to the results of electrochemical analysis, the maximum total ionic conductivity was observed in SDC20 electrolyte synthesized using triethylene glycol as the fuel among all the synthesized electrolytes (5.72 x 10–2 S.cm–1). 相似文献
964.
965.
Mehmet Kurtca Ibrahim Tumen Hasan Keskin Nurhayat Tabanca Xiangbing Yang Betul Demirci Paul E. Kendra 《Molecules (Basel, Switzerland)》2021,26(24)
The present study analyzed the chemical composition of Juniperus foetidissima Willd. essential oils (EOs) and evaluated their attractancy and toxicity to two agriculturally important tephritid fruit flies. The composition of hydrodistilled EOs obtained from leaves (JFLEO) and fruits (JFFEO) of J. foetidissima was analyzed by GC–FID and GC–MS. The main compounds were α-pinene (45%) and cedrol (18%) in the JFLEO and α-pinene (42%), α-thujone (12%), and β-thujone (25%) in the JFFEO. In behavioral bioassays of the male Mediterranean fruit fly, Ceratitis capitata (Wiedemann), both JFLEO and JFFEO showed strong attraction comparable to that observed with two positive controls, Melaleuca alternifolia and Tetradenia riparia EOs. In topical bioassays of the female Caribbean fruit fly, Anastrepha suspensa (Loew), the toxicity of JFFEO was two-fold higher than that of JFLEO, with the LD50 values being 10.46 and 22.07 µg/µL, respectively. This could be due to differences in chemical components between JFLEO and JFFEO. The JFFEO was dominated by 48% monoterpene hydrocarbons (MH) and 46% oxygenated monoterpenes (OM), while JFLEO consisted of 57% MH, 18% OM, and 20% oxygenated sesquiterpenes (OS). This is the first study to evaluate the attractancy and toxicity of J. foetidissima EOs to tephritid fruit flies. Our results indicate that JFFEO has the potential for application to the management of pest tephritid species, and further investigation is warranted. 相似文献
966.
Juste Baranauskaite Mehmet Ali Ockun Burcu Uner Cetin Tas Liudas Ivanauskas 《Molecules (Basel, Switzerland)》2021,26(20)
Essential oils have a high volatility that leads to evaporation and loss of their pharmacological effect when exposed to the environment. The objectives of the present work were to prepare microcapsules with oregano essential oil by extrusion using sodium alginate as a shell material and non-ionic surfactant polysorbate 80 as an emulsifier to stabilize the emulsion. The present study was aimed to evaluate the physical parameters of microcapsules and to compare the influence of the amount of emulsifier and the essential oil-to-emulsifier ratio on the capsules’ physical parameters and encapsulation efficiency; to our knowledge, the existing research had not yet revealed whether unstable emulsion affects the encapsulation efficiency of oregano essential oil. This study showed that increasing the emulsifier amount in the formulation significantly influenced encapsulation efficiency and particle size. Moreover, increasing the emulsion stability positively influenced the encapsulation efficiency. The emulsion creaming index depended on the emulsifier amount in the formulation: the highest creaming index (%) was obtained with the highest amount of polysorbate 80. However, the essential oil-to-polysorbate 80 ratio and essential oil amount did not affect the hardness of the microcapsules (p > 0.05). In conclusion, the obtained results could be promising information for production of microcapsules. Despite the fact that microencapsulation of essential oils is a promising and extremely attractive application area for the pharmaceutical industry, further basic research needs to be carried out. 相似文献
967.
Mehmet Somer Wilder Carrillo‐Cabrera Karl Peters Hans Georg von Schnering 《无机化学与普通化学杂志》2000,626(4):897-904
Synthesis, Crystal Structure, and Vibrational Spectra of Compounds with the Linear Dipnictidoborate (3–) Anions [P–B–P]3–, [As–B–As]3–, and [P–B–As]3– The alkali metal boron compounds M3[BX2] with X = P, As are synthesized from the alkali metals M and the binary components MX or M4X6 and BX in sealed steel ampoules (phosphides) or niobium ampoules (arsenides) at 1000 K. The compounds are obtained as bright yellow prisms (M3[BP2]) or plates (K2Na[BP2]) and yellow‐red prismatic crystals (M3[BAs2], Cs3[BPAs]) which are very sensitive against oxidation and hydrolysis. Three different structure types are formed, namely K2Na[BP2] (C2/m (No. 12); Z = 4; a new mC24 structure type); Na3[BP2] (P21/c (No. 14); Z = 4, β‐Li3[BN2] type), M3[BX2] with M = K, Rb, Cs and X = P, As and Cs3[P–B–As] (C2/c, (No. 15); Z = 4, K3[BP2] type). The bond lengths of the linear [BX2]3– anions are hardly changed and correspond to a Pauling bond order PBO = 1.9 (d(B–P) = 176.7–177.1 pm; d(B–As) = 186.5–188.0 pm). The vibrational spectra confirm the existence of unmixed and mixed units [P–B–P]3–, [As–B–As]3– and [P–B–As]3– with D∞h and C∞v symmetry, respectively. The valence force constants f(B–X) and the corresponding Siebert bond orders, calculated from the frequencies, are discussed and compared with those of the isoelectronic anions and molecules. 相似文献
968.
Halil Çetişli Mehmet Karakuş Emin Erdem Hasalettin Deligöz 《Journal of inclusion phenomena and macrocyclic chemistry》2002,42(3-4):187-191
The synthesis of azo compounds [4-(N'-2-thiazol-2-ylsulfanyl)-4'-hydroxyazo benzene (1), 4-(N'-2-thiazol-2-ylsulfanyl)-2'-hydroxy-5-tert-butylazobenzene (2), 7-[4-(N'-2-thiazol-2-ylsulfanyl)phenylazo-8-hydroxy quinoline (3)] have been carried out by reacting phenol, 4-tert-butyl phenol and 8-hydroxy quinoline with N'-2-thiazol-2-ylsulfanylamide as coupling component. The resulting ligands (2 and 3) were treated with two transition metal salts (e.g., CuCl22H2O andNiCl26H2O). Cu(II) and Ni(II) complexes of the azo derivative ofphenol were obtained and characterised by IR, UV-Vis, 1H NMR, spectroscopic and elemental analysis techniques. All the complexes have a metal : ligand ratio of 1 : 2 and are square-planar. 相似文献
969.
Mehmet Somer Umut Aydemir Michael Baitinger Hans Georg von Schnering 《无机化学与普通化学杂志》2006,632(7):1281-1286
Vibrational spectra of the compounds M4E4 (M = K, Rb, Cs; E = Ge, Sn) and of β‐Na4Sn4 with the cluster anions [E4]4? were analysed based on the point group of isolated tetrahedranide units. The lower individual symmetry of the anions in the real structure being more patterned and complex primarily affects the spectra of the tetrahedro‐tetragermanides. ν3(F2) clearly splits both in Raman and IR and in the case of K4Sn4 only in IR. Rb4Sn4 and Cs4Sn4 exhibit very simple spectra with three bands in Raman and one band in IR. The breathing mode ν1(A1) for the quasi isolated [E4]4? cluster appears only in the Raman spectrum and is hardly influenced by the structural environment and by the nature of the alkali metal cations: ν1(A1) = 274 cm?1 ([Ge4]4?) and 183‐187 cm?1 ([Sn4]4?), respectively. The calculated valence force constants fd(E–E) are: [Ge4]4? : fd = 0.89 Ncm?1 ( K ), 0.87 Ncm?1 ( Rb ), 0.86 Ncm?1 ( Cs ) and [Sn4]4? : 0.67 Ncm?1 ( Na ), 0.66 Ncm?1 ( K ), 0.67 Ncm?1 ( Rb ), 0.68 Ncm?1 ( Cs ). Both, the frequencies and the force constants fit well into the range previously reported. 相似文献
970.
Dr. Mehmet Atilla Tasdelen Prof. Dr. Yusuf Yagci 《Angewandte Chemie (International ed. in English)》2013,52(23):5930-5938
Spatial and temporal control over chemical and biological processes, both in terms of “tuning” products and providing site‐specific control, is one of the most exciting and rapidly developing areas of modern science. For synthetic chemists, the challenge is to discover and develop selective and efficient reactions capable of generating useful molecules in a variety of matrices. In recent studies, light has been recognized as a valuable method for determining where, when, and to what extent a process is started or stopped. Accordingly, this Minireview will present the fundamental aspects of light‐induced click reactions, highlight the applications of these reactions to diverse fields of study, and discuss the potential for this methodology to be applied to the study of biomolecular systems. 相似文献