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101.
It is shown that the bicyclic triaminophosphine P(i-BuNCH2CH2)3N serves as an effective ligand for the palladium-catalyzed amination of a wide array of aryl bromides and iodides. Other bicyclic or acyclic triaminophosphines, even those of similar basicity and/or bulk, were inferior. 相似文献
102.
T. R. Govindachari K. Nagarajan S. Rajeswari H. Suguna B. R. Pai 《Helvetica chimica acta》1977,60(7):2138-2150
Debenzylation of 1-(3-benzyloxybenzyl)-1,2,3,4-tetrahydroisoquinolines 1 , 6 , 7 with hydrochloric acid and ethanol gave the corresponding phenolic isoquinolines 2 , 8 , 9 and tetrahydroprotoberberines 4 , 12 , 13 . Compounds 2 , 8 , 9 on photolysis also gave, besides the expected noraporphines 3 , 10 , 11 , the tetrahydroprotoberberines 4 , 12 , 13 [1–4] (Schemes 1 and 2). 6-Benzyloxy-1-(5-benzyloxy-2-bromo-benzyl)-1,2,3,4-tetrahydroisoquinoline (27a) containing no methoxy or methylenedioxy groups either in ring A or C does not give protoberberine during debenzylation; but 28 , the debenzylation product of 27a , on photolysis gives both the noraporphine 29 and the tetrahydroprotoberberine 30 (Scheme 6), proving that during debenzylation of 1-(3-benzyloxybenzyl)-1,2,3,4-tetrahydroisoquinolines containing additional methoxy or methylenedioxy groups, the necessary formaldehyde comes from the latter groups. During photolysis both the methoxy groups (methylenedioxy groups) and the C(3) atom of the tetrahydroisoquinoline moiety provide the formaldehyde. Veratrole under debenzylation and photolytic conditions and tetrahydroisoquinoline under the latter condition also give rise to formaldehyde (Schemes 8 and 10). The novel bromohomoprotoberberine 43 along with 42 was formed during debenzylation of the 1-phenethyl-1,2,3,4-tetrahydroisoquinoline 41 . Photolysis of 42 yielded the novel nor-homoaporphine 44 , in addition to 43 ; the latter was debrominated to give the homoberbine 45 . 相似文献
103.
R. Nagarajan 《Journal of colloid and interface science》1982,90(2):477-486
Surfactant solutions in which large cylindrical micelles form are characterized by two essential features, namely, they are polydisperse and the average micelle size is proportional to the square root of the micelle concentration. These features of the cylindrical micelles imply that the intrinsic viscosities of these micellar solutions should also depend on the concentration of micelles. This fact has been ignored in all past treatments of micellar viscosity data. Here, viscosity data available in literature were reexamined in terms of concentration-dependent intrinsic viscosity so as to evaluate the rigidity or the flexibility of the large micelles. It is found that the interpretation of viscosity data assuming that the large micelles are rigid rods is in very good agreement with the theoretically anticipated essential features of large micelles. It is concluded that large micelles can be satisfactorily represented by rigid rods rather than by flexible rods or coils. 相似文献
104.
A brief survey of vibrational spectral studies for the four isotopic species of dioxygen monofluoride has been made. On the basis of group theoretical considerations, symmetry coordinates have been constructed and kinetic energy matrices (orG matrix elements), potential energy matrices, and secular equations have been derived to calculate the valence force constants. The mean-square amplitudes and root-mean-square amplitudes for both the bonded and nonbonded atom pairs have been calculated at the room temperature. On the basis of a rigid rotator and harmonic oscillator model, enthalpy function, free enthalpy function, entropy, and heat capacity have been calculated from 200 to 2000 °K for all the four isotopic species. On the basis of a delta-function potential model based on the variational method and delta-function electronic wave functions, the bond parallel components, the bond perpendicular components, the contribution by the nonbonding electrons, and the average molecular polarizability have been calculated. The results obtained from these studies clearly confirm a double bond character for the oxygen—oxygen distance and a bond order of less than one-half for the oxygen—fluorine distance. The results have been discussed in relation to the nature of the two characteristic bonds involved in this molecular system. 相似文献
105.
S. K. Malik G. K. Shenoy P. L. Paulose R. Nagarajan A. E. Dwight P. P. Vaishnava C. W. Kimball 《Hyperfine Interactions》1987,34(1-4):377-380
The compounds EuPdGa and EuPtGa show lattice volume anomaly indicating the abnormal valence state of Eu. in these compounds. Magnetization studies reveal that these compounds are magnetically ordered with a moment of 7 B/f.u. at 5K. The Curie temperatures obtained from the low field ac susceptibility measurements are 38K for EuPdGa and 36K for EuPtGa.151Eu Mössbauer studies at 300K gave large negative isomer shifts (relative to SmF3) and show a hyperfine split pattern at 4.2K in both the compounds. These results suggest that Eu is in a divalent state in EuPdGa and EuPtGa. 相似文献
106.
Reaction of 1-(2-nitrophenoxy)naphthalene or its β-isomer with triethylphosphite produces benzo[a]phenoxazines and , through the intermediate . 相似文献
107.
This article discusses the extraction and characterization of new natural fiber extracted from red coconut empty fruit bunch. The physicochemical, mechanical, and thermal properties of alkali-treated red coconut empty fruit bunch fibers (ARCEFBFs) were reported and compared with other natural fibers for the first time. Cellulose content (65.02 wt%), wax (0.32 wt%), density (1.421 g/cc), and tensile strength (1299.49 MPa) were identified in ARCEFBFs. Fourier transform infrared spectroscopy and X-ray diffraction analysis confirmed that ARCEFBFs are rich in cellulose content with crystallinity index of 53.6%. Thermogravimetric analysis revealed that these fibers are thermally stable until 270.48°C. 相似文献
108.
Abhishek Kumar Subhalakshmi Nagarajan Ke Yang Robinson Anandakathir Jagdeep Singh Ramaswamy Nagarajan 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):963-966
A novel, one step and simple methodology for the fabrication of submicron scale silver patterns is demonstrated. The photosensitivity of an organic silver salt has been utilized for this purpose of fabrication. The silver-organometallic compound is converted to metallic silver selectively in the illuminated regions. Surface morphology was studied by scanning electron microscopy (SEM). Energy dispersion spectroscopy (EDS) shows the presence of silver in the developed film. X-ray photoelectron spectroscopy (XPS) confirms the formation of metallic silver. Feature sizes of the order of 200 nm have been achieved using this technique. 相似文献
109.
110.
Soumitra Satapathi Sethumadhavan Ravichandran Ravi Mosurkal Subhalakshmi Nagarajan Lian Li Ramaswamy Nagarajan 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1061-1066
Resveratrol (3,5,4′ trihydroxy trans-stilbene) is a plant based phenolic compound. Enzymatic oligomerization of trans-resveratrol using horseradish peroxidase followed by characterization of the oligomer is presented. The oligomerization reaction was monitored using UV-Visible absorption and fluorescence spectroscopies. The oligomer exhibits strong two-photon-induced fluorescence. Computational modeling using spin-density calculations was performed to investigate the most probable reaction sites and the nature of products formed in the oligomerization process. 相似文献