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981.
Kevin C. Seavey Indrajit Ghosh Richard M. Davis Wolfgang G. Glasser 《Cellulose (London, England)》2001,8(2):149-159
Thermoplastic fiber composites were prepared using high modulus lyocell (regenerated cellulose) fibers for reinforcement and cellulose acetate butyrate (CAB) as matrix. Choices were made with regard to fiber options (fabric versus continuous tow) and method of matrix deposition (prepregging by powder coating, film stacking, or solution impregnating). The results suggest that solution-prepregged fiber tow consolidated at circa 200°C produced unidirectional consolidated panels with tensile strength, modulus, and strain at failure values of approximately 250MPa,>20GPa and 3–4%, respectively, at fiber volume contents of approximately 60%. Modulus and ultimate tensile strength increased with fiber content, and modulus followed rule-of-mixture behavior. Adequate surface wetting and matrix-fiber adhesion were found with solution-prepregged composites. The unexpectedly low strain at failure (2 to <4%) was attributed to brittle matrix failure, and failure surfaces revealed that the fibers, for the most part, remained intact after the matrix had failed. 相似文献
982.
983.
Transport in Porous Media - In this paper, an approximate integral equation solution for a horizontal, unsteady flow of two viscous incompressible fluids is derived. Wettability variation of the... 相似文献
984.
985.
Shyamal Kumar Chattopadhyay Mosarraf Hossain Saktiprosad Ghosh Arur Kumar Guha 《Transition Metal Chemistry》1990,15(6):473-477
Summary The chelating behaviour of two biologically active ligands, pyridine-2-carboxaldehyde(4-phenyl) thiosemicarbazone(L1H) and pyridine-2-carboxaldehyde thiosemicarbazone(LH), towards FeIII, CoIII, FeII and RhIII has been investigated. The ligands act as tridentate N–N–S donors, resulting in the formation of bis-chelate complexes of the type MIII(A)2X·nH2O (A=L1 or L; X=Cl, ClO4; M=CoIII, RhIII, FeIII), FeII(L1H)2SO4·2H2O and FeII(L1)2·H2O. Biological activity of the ligands and the metal complexes in the form ofin vitro antibacterial activities towardsE. coli has been evaluated and the possible reasons for enhancement of the activity of ligands on coordination to metal ion is discussed. 相似文献
986.
Two tridentate N,N,O donor Schiff bases, HL1 (4-(2-ethylamino-ethylimino)-pentan-2-one) and HL2 (3-(2-amino-propylimino)-1-phenyl-butan-1-one) on reaction with CuII acetate in presence of triethyl amine yielded two basal-apical, mono-atomic acetate oxygen-bridging dimeric copper(II) complexes, [Cu2L12(OAc)2] (1), [Cu2L22(OAc)2] (2). Whereas two other similar tridentate ligands HL3 (4-(2-amino-propylimino)-pentane-2-one) and HL4 (3-(2-amino-ethylimino)-1-phenyl-butan-1-one) under the same conditions produced a mixture of the corresponding dimers and a one-dimensional alternating chain of the dimer and copper acetate moiety, [Cu4L32(OAc)6]n (3) and [Cu4L42(OAc)6]n (4), formed by a very rare μ3 bridging mode of the acetate ion. All four complexes (1–4) have been characterized by X-ray crystallography. The isotropic Hamiltonian, H = −JS1S2 has been used to interpret the magnetic data. Magnetic measurements of 1 and 2 in the temperature range 2–300 K reveal a very weak antiferromagnetic coupling for both complexes (J = −0.56 and −1.19 cm−1 for 1 and 2, respectively). 相似文献
987.
Surface enhanced Raman scattering of 2,2' biquinoline adsorbed on colloidal silver particles 总被引:1,自引:0,他引:1
Chowdhury J Ghosh M Misra TN 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,(11):2107-2115
Surface enhanced Raman scattering (SERS) in silver sol and normal Raman spectra in the bulk and in solution of 2,2' biquinoline (BQ) molecule have been investigated. The observed Raman bands along with their corresponding FTIR bands have been assigned based on the established assignments of the vibrational bands of the parent napthalene and quinoline molecules. Existence of both the cis and trans form of the BQ molecule in solution and in the bulk are inferred from the normal Raman and FTIR spectra, whereas SERS study reveal that in the surface adsorbed state the molecule exists in the cis form. Definite evidence of the charge transfer interaction to the overall contribution in the SER enhancement have been reported. The excitation profile also supports the CT interaction. Estimated enhancement factor of the principal SERS bands indicate that the molecule is adsorbed on the silver surface through both the nitrogen atoms with the molecular plane almost perpendicular to the surface. This preferred orientation of the molecule is in conformity with its existence in the cis form in the surface adsorbed state. 相似文献
988.
A series of mixed ligand cadmium(II) complexes having 3,5-dimethylpyrazole and aromatic carboxylate are structurally characterized. The effect of substituent on aromatic ring and also the effect of composition on co-ordination behavior of these complexes are ascertained. Hydrogen bonded self-assembled mononuclear complexes are obtained from composition [Cd(L)2(La)2] where La = 3,5-dimethylpyrazole L = R–C6H4COO– [R = H (1), 2-Cl (2), 4-OH (3), 2-OH (4)]. The cadmium complex (5) having composition [Cd(L)2(La)(H2O)] (L = 2-NO2–C6H4COO–) is tetra-nuclear. The complex has eight and six co-ordination around cadmium and self-assembles through hydrogen bonding leading to form extended chain structure. The four complexes (1–4) have six co-ordinated trigonal prismatic geometry around cadmium ions. Cadmium complexes having composition [Cd(L)2(La)] such as R = 4-NO2 (6), 4-Cl (7), and 1-naphthoate complex (8) are co-ordination polymers with seven co-ordination geometry around cadmium. In these co-ordination polymers different Cd–Cd distances are observed for alternate pair of cadmium ions. For example in the case of the co-ordination polymer of 4-nitro-benzoate complex the Cd–Cd distance between alternate pairs are 4.138 Å, and 3.748 Å. The 1-naphthoate complex having pyridine has composition [Cd(L)2(Lb)2](H2O)] (9) where Lb = pyridine and L = 1-naphthoate has seven co-ordination with a distorted pentagonal bipyramid geometry. 相似文献
989.
Manisha Gurnani Prangya Rath Abhishek Chauhan Anuj Ranjan Arabinda Ghosh Rup Lal Nobendu Mukerjee Nada H. Aljarba Saad Alkahtani Vishnu D. Rajput Svetlana Sushkova Evgenya V. Prazdnova Tatiana Minkina Tanu Jindal 《Molecules (Basel, Switzerland)》2022,27(6)
Antibiotic resistance is one of the major growing concerns for public health. Conventional antibiotics act on a few predefined targets and, with time, several bacteria have developed resistance against a large number of antibiotics. The WHO has suggested that antibiotic resistance is at a crisis stage and identification of new antibiotics and targets could be the only approach to bridge the gap. Filamentous Temperature Sensitive-Mutant Z (Fts-Z) is one of the promising and less explored antibiotic targets. It is a highly conserved protein and plays a key role in bacterial cell division by introducing a cytokinetic Z-ring formation. In the present article, the potential of over 165 cyanobacterial compounds with reported antibiotic activity against the catalytic core domain in the Fts-Z protein of the Bacillus subtilis was studied. The identified cyanobacterial compounds were screened using the GLIDE module of Maestro v-2019-2 followed by 100-ns molecular dynamics (MD) simulation. Ranking of the potential compound was performed using dock score and MMGBSA based free energy. The study reported that the docking score of aphanorphine (−6.010 Kcalmol−1) and alpha-dimorphecolic acid (ADMA) (−6.574 Kcalmol−1) showed significant role with respect to the reported potential inhibitor PC190723 (−4.135 Kcalmol−1). A 100 ns MD simulation infers that Fts-Z ADMA complex has a stable conformation throughout the progress of the simulation. Both the compounds, i.e., ADMA and Aphanorphine, were further considered for In-vitro validation by performing anti-bacterial studies against B. subtilis by agar well diffusion method. The results obtained through In-vitro studies confirm that ADMA, a small molecule of cyanobacterial origin, is a potential compound with an antibacterial activity that may act by inhibiting the novel target Fts-Z and could be a great drug candidate for antibiotic development. 相似文献
990.