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171.
The anthocyanin composition of rose wine made from cv. Öküzgözü, a variety of grape native to Turkey, and the effect of maceration time (3, 6, 12, 18, or 24 h) on the anthocyanin content of the wine have been investigated. High-performance liquid chromatography with diode-array detection (HPLC-DAD) and mass spectrometry (MS) were used for anthocyanin analysis. Thirteen different anthocyanins, including five glucosides, five acetyl glucosides, and three coumaroyl glucosides were identified and quantified. It was found that an important characteristic of Öküzgözü rose wine was the presence of a large amount of malvidin-3-glucoside and its acylated esters. The total anthocyanin content of the wine increased with increasing maceration time. On the basis of sensory analysis, the most preferred wine was that produced with 3-h maceration, because of its better color and general flavor attributes. 相似文献
172.
Christopher Imrie Phumelele Kleyi Thomas I.A. Gerber Jennifer Look 《Journal of organometallic chemistry》2007,692(16):3443-3453
Grinding of 1,1′-ferrocenedicarboxaldehyde with a 2.2 molar equivalent of an aromatic amine in a solvent-free environment provided excellent yields of 1,1′-ferrocenyldiimines. After mixing the aldehyde and amines, a gum or melt formed which eventually solidified to the product. An analytically pure sample of the product was obtained by cold recrystallization. Grinding of ferrocenecarboxaldehyde and 4-substituted phenylacetonitriles under solvent-free conditions provided good yields of the corresponding ferrocenylacrylonitriles. The yield in this reaction was very low when the substituent group para to the acetonitrile group was electron-donating. 相似文献
173.
Vanessa Cerezo 《Tetrahedron》2007,63(42):10445-10453
Microwave irradiation efficiently promoted the Suzuki-Miyaura reaction of a 5-bromohistidine with various arylboronic acids in the presence of a palladium catalyst. This methodology allowed the synthesis of histidines substituted at position 5 of the imidazole ring with a phenyl, a substituted phenyl, a pyridyl or a thienyl ring. The corresponding 5-arylhistidines were obtained in moderate to good yields. 相似文献
174.
A two step process for converting ketone or aldehyde via 1,1-dichloro-1-alkenes to the corresponding 1,1,1-trifluoroderivatives is described, based on HF addition and chlorine-fluorine exchange under superacidic conditions. 相似文献
175.
Ziya Kantarci Celal Bayrak 《Journal of inclusion phenomena and macrocyclic chemistry》1998,30(1):59-68
IR spectra of Mn(trimethylenediamine)Zn(CN)42C6H6 and IR and Raman spectra of Zn(trimethylenediamine)Zn(CN)4_2C6H6 are reported. The spectral data suggest that the host frameworks of these compounds are similar to those of the tn-Td-type Cd(trimethylenediamine)M(CN)4_2benzene (M = Cd or Hg) and the chelated pn-Td-type Cd(propylenediamine)Cd(CN)4_1,2-dichloro-ethane clathrates, respectively. 相似文献
176.
Spectral quantities of cyclopropane, cyclobutane, cyclohexane, and of several derivatives, have been calculated by a semiempirical all-valence electron SCF-CI MO method. In cyclopropane, HOMO is practically localized in the carbon-frame, and LVMO is purely so. In cyclobutane, these two MO's are based on C-H bonds, while cyclohexane holds an intermediate position. Despite the overall similarity-experimental and computed-of the spectra of these molecules, assignments are non-parallel. Like cyclopropane, cyclobutane can extend conjugation, but to a diminished degree; cyclohexane behaves in this respect like an acyclic alkane. An interpretation of this gradation, in terms of the nature of high-lying MO's, is proposed. 相似文献
177.
Summary Combined capillary gas chromatography/mass spectrometry has been used to characterize the basic fraction of Mexican marijuana and standard tobacco smoke condensates. A thermostable Superox-coated glass capillary column permitted elution of relatively large nitrogen-containing compounds. Substantial qualitative and quantitative differences between the two materials were noted.Dedicated to Dr. L. S. Ettre on the occasion of his 60th birthday. 相似文献
178.
Bulk-modified epoxy-graphite tyrosinase biosensors were fabricated by four different procedures. The influence of these fabrication procedures on the analytical performance of the enzyme electrode in an amperometric wall-jet flow cell has been studied. The bioprobe performance is assessed by cyclic voltammetry. Higher current densities and narrower peaks were obtained when the enzyme was introduced in the dry state into the epoxy-graphite material, instead of introducing it previously dissolved in the buffer. In the F1 system responses of 11.79 μA cm−2 and 1.43 μA cm−2 are then obtained for catechol and phenol respectively for 50 μL injections of 20 μM solutions. Moreover, if gold/palladium is introduced into the epoxy-graphite, a further increase in current is achieved resulting in 27.70μA cm−2 and 4.90μA cm−2for catechol and phenol, respectively. This biosensor can operate in aqueous as well as in mixed aqueous-organic environments. 相似文献
179.
The reducing system NiCl2·2H2O—Li—arenecat (cat is catalyst) was proposed for use to reduce a wide range of organic compounds, including alkenes, alkynes, carbonyl compounds, imines, halogenated derivatives, sulfonates, aromatic compounds, hydrazines, azo and azoxy compounds, N-oxides, and nitrones. The degree of reduction can be controlled for some substrates. Deuterium can be incorporated in the reaction products using nickel chloride deuteriohydrate. Nitrones, N-alkoxyamides, and acyl azides are also reduced with the Li—arenecat system containing no nickel salt. 相似文献
180.
Pro-oxidant properties of phenolic antioxidants, which are derived from their iron recycling reactivity, render the traditional deoxyribose degradation assay invalid to assess the hydroxyl radical-scavenging activity in Fenton-type reaction systems. In the present paper, we studied in detail the interactions between iron and phenolic compounds, and established a kinetic deoxyribose method by taking advantage of the distinct difference between the completion time of Fenton reaction and that of the iron-reducing process. With the newly established kinetic method, we investigated the effects of phenolics on hydroxyl radical formation in a Fenton-type system and determined successfully the second rate constants of hydroxyl radical-scavenging reactions. The site-specific and non-site-specific hydroxyl radical-scavenging ability suggested that both direct hydroxyl radical-scavenging potency and iron-chelating capacity accounted for their inhibitory effects on deoxyribose oxidation degradation. This method, more simple, time saving, and applicative than the traditional deoxyribose assay, produces as accurate results (RSD<0.05, with dynamic range from 7.5 to 575 μM) as typical methods, such as radiolysis technology, and may be of significance in evaluating and screen the hydroxyl radical-scavenging antioxidants. 相似文献