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排序方式: 共有491条查询结果,搜索用时 15 毫秒
171.
Samiulla DS Vaidyanathan VV Arun PC Balan G Blaze M Bondre S Chandrasekhar G Gadakh A Kumar R Kharvi G Kim HO Kumar S Malikayil JA Moger M Mone MK Nagarjuna P Ogbu C Pendhalkar D Rao AV Rao GV Sarma VK Shaik S Sharma GV Singh S Sreedhar C Sonawane R Timmanna U Hardy LW 《Molecular diversity》2005,9(1-3):131-139
Natural product analogs are significant sources for therapeutic agents. To capitalize efficiently on the effective features of naturally occurring substances, a natural product-based library production platform has been devised at Aurigene for drug lead discovery. This approach combines the attractive biological and physicochemical properties of natural product scaffolds, provided by eons of natural selection, with the chemical diversity available from parallel synthetic methods. Virtual property analysis, using computational methods described here, guides the selection of a set of natural product scaffolds that are both structurally diverse and likely to have favorable pharmacokinetic properties. The experimental characterization of several in vitro ADME properties of twenty of these scaffolds, and of a small set of designed congeners based upon one scaffold, is also described. These data confirm that most of the scaffolds and the designed library members have properties favorable to their utilization for creating libraries of lead-like molecules.These authors have contributed equally to this work. 相似文献
172.
173.
van Eis MJ van Der Linde BS de Kanter FJ de Wolf WH Bickelhaupt F 《The Journal of organic chemistry》2000,65(14):4348-4354
In contrast to the terminal phosphinidene complex PhPW(CO)(5) (2), which adds to [5]metacyclophane (1) in a 1,4-fashion, dichlorocarbene preferentially adds in a 1,2-fashion to the formal "anti-Bredt" type double bond of the aromatic ring of 1 to afford the norcaradiene 11b, which immediately rearranges to the bridged cycloheptatriene 12b and further by a [1,5] sigmatropic chlorine migration to the isomeric 13b as the first observable product. More slowly, the latter isomerizes via a dissociative mechanism to give 15b. A computational study supports the notion that the [1,5] chlorine migration in the rearrangement 12b --> 13b, for which an activation barrier of 70.2 kJ mol(-)(1) was calculated, is essentially concerted with minor charge separation. In contrast, the analogous [1,5] chlorine migration in the flat model compound 7,7-dichlorocycloheptatriene (12a) displays features of a dissociative pathway. 相似文献
174.
Positional disorder due to loss of translational symmetry is suggested as being responsible for most of the concentration dependence of the electrical resistivity of certain disordered transition metal alloys. It is then argued that in such cases the existence of tunneling states should be observable at low temperatures. Measurements of the thermal conductivity on Ti0.67V0.33 between 0.06 and 10 K confirm this conjecture. 相似文献
175.
Juan G. Andrade Jayaraman Chandrasekhar Paul Von Ragu Schleyer 《Journal of computational chemistry》1981,2(2):207-211
Molecular orbital calculations on the C4H2 potential energy surface indicate singlet trialene (1) not only to be thermodynamically unstable, but also to have negligible barriers to interconversion to diacetylene. 相似文献
176.
M. V. S. Chandrasekhar Rao G. Sree Krishna Murty K. Radha Krishna S. Bhuloka Reddy G. Satyanarayana C. V. Raghavaiah D. L. Sastry S. N. Chintalapudi 《Zeitschrift für Physik A Hadrons and Nuclei》1990,335(1):25-29
TheK-electron capture probabilities for the 1/2? → 3/2? and 1/2? → 1/2+ transitions in the decay of105Ag were measured for the first time using the sum coincidence method. The experimental PK values were estimated to be 0.824 ± 0.042 and 0.851 ±0.046 for the allowed and first-forbidden beta transitions, respectively in agreement with the theory. The PL experimental values to these two levels were also computed using the experimental PL/PK values reported by earlier authors. These results are also found to be consistent with the theoretical PL values. 相似文献
177.
Jeyaraman Chandrasekhar Prem Kishore Mehrotra Sankaran Subramanian Periakaruppan T. Manoharan 《Theoretical chemistry accounts》1979,53(3):293-296
Siegbahn's potential model as extended by Ellison et al. is used with density matrix elements calculated by the NDDO/2 procedure, to correlate the K-shell binding energy shifts of C, N and O atoms in a few molecules containing only the first-row atoms. The correlation is not superior to that obtained with the CNDO/2 method when only the monopole term is retained in calculating the Madelung potential energy. However, the results are in excellent agreement with experiment when the two-parameters model including the dipole and quadrupole terms is used. 相似文献
178.
1,2-Hydride shift barriers in classical carbenium ions increase with decreasing ring size; this can be attributed to the increased strain of the H bridged structures in the small rings. 相似文献
179.
G.S. Ranganath S. Chandrasekhar U.D. Kini K.A. Suresh S. Ramaseshan 《Chemical physics letters》1973,19(4):556-560
A rigorous theory is developed of the optical properties of a mixture of right-handed and left-handed cholesteric liquid crystals, taking into account the effect of absorption. The dependence of the rotatory power and circular dichroism on pitch and on sample thickness is discussed. 相似文献
180.
Liquid crystals of disc-like molecules 总被引:2,自引:0,他引:2
Thermotropic mesomorphism has been observed in pure compounds consisting of simple disc-like molecules, viz., benzene-hexa-n-alkanoates. Thermodynamic, optical and x-ray studies indicate that the mesophase is a highly ordered lamellar type of liquid
crystal. Based on the x-ray data, a structure is proposed in which the discs are stacked one on top of the other in columns
that constitute a hexagonal arrangement, but the spacing between the discs in each column is irregular. Thus the structure
has translational periodicity in two dimensions and liquid-like disorder in the third. 相似文献