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971.
Controlled release of 2‐heptanone using starch gel and polycaprolactone matrices and polymeric films
Gregory M. Glenn Artur P. Klamczynski Justin Shey Bor‐Sen Chiou Kevin M. Holtman Delilah F. Wood Charles Ludvik Gloria DeGrandi Hoffman William J. Orts Syed Imam 《先进技术聚合物》2007,18(8):636-642
Varroa jacobsoni is a parasitic mite that is threatening the honeybee industry in many parts of the world. 2‐Heptanone, a natural product made by honeybees at low concentrations, is effective at elevated concentrations in controlling mite populations in honeybee colonies, especially when released over a 42 day period. An extrusion process was used to encapsulate 14, 18, and 25% 2‐heptanone in a polycaprolactone (PCL) matrix. Less than 18% of the 2‐heptanone was encapsulated in the PCL matrix. The high vapor permeability of PCL to 2‐heptanone resulted in a high flux rate and limited the usefulness of PCL as an encapsulation matrix for controlled‐release devices. A starch gel containing three times its weight in 2‐heptanone was prepared from starch‐based microcellular foam (MCF). The gel had compressive, tensile, and flexural strength values in the range of 0.56 to 1.9 MPa. 2‐Heptanone quickly evaporated from non‐laminated gels. However, when the gel was laminated with different polymeric films, a wide range of flux rates was obtained. The T50 for gels laminated or coated with poly(vinyl alcohol) (PVAL, 99% hydrolyzed) and ethylene‐vinyl alcohol copolymer (EVAL) was 72 and 1030 days, respectively. The most promising film was a starch/glycerol film that released 50% of the 2‐heptanone (T50) in approximately 13 days. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
972.
Syed Raziullah Hussaini 《Tetrahedron letters》2004,45(6):1125-1127
A concise approach to cis-2,5-disubstituted pyrrolidines is reported, which relies upon N-tert-butoxycarbonylmethyl substitution in a substrate derived from pyroglutamic acid. The method is especially noteworthy since a significant improvement in the conditions for a key Lawesson’s reaction have been established. Regioselective enolate generation and alkylation permits extension of the C-5 side chain. 相似文献
973.
Pongarotene (1), a new rotenoid and karanjin (2), a known flavonol, were isolated from the seeds of Pongamia pinnata. The structure determination of these compounds were based on spectral analyses including 2D-NMR. The antifungal, antibacterial and phytotoxicity results of pure compounds 1 and 2 as well as of the methanol (M) and ethyl acetate (E) crude extracts are also being reported. 相似文献
974.
Steam distilled oils of some species of the genus Citrus and Cymbopogon citratus were analyzed by GC-MS. It is observed that citral b was the most common constituent of the oils, which could be a good inhibitor of beta-glucuronidase as all the tested essential oils showed significant inhibition of beta-glucuronidase. IC50 values of a mixture of citral a and b also proved the hypothesis. The same oils also exhibited positive response against tested microbes. 相似文献
975.
A new kind of affinity electrophoresis called antibody affinity electrophoresis is a technique used to capture protein antigens based on their interactions with specific monoclonal or polyclonal antibodies incorporated in the polyacrylamide gel. Polyclonal anti-glutathione-S-transferase (anti-GST), monoclonal anti-bovine serum albumin (anti-BSA), and polyclonal anti-human alpha-lactalbumin are embedded in distinct areas of a 7.5% native polyacrylamide gel. Some of the embedded antibodies get covalently and/or noncovalently incorporated into the gel matrix network. Under electrophoresis conditions, these antibodies do not show significant electrophoretic mobility, as compared to their specific protein antigen analytes. We observed that electrophoretic migration of GST, BSA, and protein G ceases when they encounter anti-GST, anti-BSA, and immunoglobulin G, respectively. 相似文献
976.
Tahir Ali Khan Syed Sirajul Hasan Saji P. Varkey Manzoor Ahmad Rather Mohammad Shakir 《Transition Metal Chemistry》1996,21(3):283-286
Summary A new series of 15- and 16-membered dioxotetraamine macrocyclic complexes, [ML1X2] and [ML2X2] (M = MnII, CoII, NiII, CuII or ZnII; X = Cl or NO3), respectively, were prepared by reacting o-aminobenzoic acid, diaminoethane or 1,3-diaminopropane with 2,4-pentanedione in the presence of metal ions. The complexes were identified by analytical data, i.r., 1H-n.m.r., e.p.r. and u.v.-vis. spectroscopies, and by conductivity and magnetic moment measurements. They exhibit an octahedral geometry leaving the peptide oxygen uncoordinated. They are air stable and insoluble in water and most organic solvents, but soluble in DMSO and DMF. The low conductivity suggests that the complexes are non-ionic. 相似文献
977.
A selective and sensitive visible spectrophotometric method has been described for the quantitation of diltiazem hydrochloride in commercial dosage forms. The method is based on the reaction of the tertiary amino group of the drug with sodium hypochlorite to form the chloro drug derivative, followed by the destruction of the excess hypochlorite by sodium nitrite and the subsequent development of blue color takes place by the reaction of chloro derivative of drug with starch and potassium iodide in sodium bicarbonate medium. The maximum absorbance of the resulting blue solution is read at 540 nm. Under the optimized experimental conditions, Beer's law is obeyed in the concentration range of 2.5–25.0 μg mL?1 with a linear regression equation of A = 9.85 × 10?4 + 4.90 × 10?2 C and coefficient of correlation, r = 0.9999. The molar absorptivity is found to be 2.26 × 104L mol?1 cm?1. The limits of detection and quantitation of the proposed method are 0.12 and 0.37 μg mL?1, respectively. The proposed method has been successfully applied for the quantitation of diltiazem hydrochloride in commercial dosage forms. The results of the proposed method compared with those of Abdellatef's spectrophotometric method presented good mean recovery with acceptable true bias of all pharmaceutical samples within ± 2.0%. 相似文献
978.
In this paper a formula for the coefficient of λ
n-gh+g-1 in the chromatic polynomial of a linear h-uniform hypergraph H of order n and girth g is proposed provided (g, h) ≠ (3, 3). This formula involves 13 types of spanning subhypergraphs of H for 3 ≤ h ≤ 5. 相似文献
979.
A. Lopez-Martens K. Hauschild A. V. Yeremin O. Dorvaux A. V. Belozerov Ch. Briançon M. L. Chelnokov V. I. Chepigin D. Curien P. Désesquelles B. Gall V. A. Gorshkov M. Guttormsen F. Hanappe A. P. Kabachenko F. Khalfallah A. Korichi A. C. Larsen O. N. Malyshev A. Minkova Yu. Ts. Oganessian A. G. Popeko M. Rousseau N. Rowley R. N. Sagaidak S. Sharo A. V. Shutov S. Siem L. Stuttgé A. I. Svirikhin N. U. H. Syed Ch. Theisen 《The European Physical Journal A - Hadrons and Nuclei》2007,32(3):245-250
Isomeric states in 253No have been investigated by conversion electron and γ -ray spectroscopy with the GABRIELA detection system. The 31μs isomer
reported more than 30 years ago is found to decay to the ground state of 253No by the emission of a 167keV M2 transition. The spin and parity of this low-lying isomeric state are established to be 5/2+ . The presence of another longer-lived isomeric state is also discussed. 相似文献
980.
Syed Masood Husain Marie Theres Heim Dirk Schepmann Bernhard Wünsch 《Tetrahedron: Asymmetry》2009,20(12):1383-1392
A very short (three steps) asymmetric synthesis of enantiomerically pure 1,4-disubstituted tetrahydro-1H-3-benzazepines 14 has been elaborated upon, starting from the trans- and cis-configured 11a-substituted 3-phenyl-2,3,11,11a-tetrahydro[1,3]oxazolo[2,3-b]-[3]-benzazepin-5(6H)-ones 6 and 7. The stereoisomerically pure lactams 6 and 7 were benzylated to give 6-benzyl-substituted products 8 and 9. NOE experiments showed a trans-configuration of the benzyl residue and the residue in the 11a-position indicated that the stereochemistry of the benzylation reaction was controlled by the stereocenter at the 11a-position. Reduction of the benzylated tricyclic benzolactams 8 and 9 with AlCl3/LiAlH4 (1/3) yielded the 1,3,4-trisubstituted 3-benzazepines 12 and 13, which were formed stereoselectively with the retention of configuration. Finally, removal of the N-(2-hydroxy-1-phenylethyl) residue by hydrogenolytic cleavage resulted in the formation of enantiomerically pure 1,4-disubstituted 3-benzazepines 14. The σ1, σ2, and NMDA receptor affinities of the enantiomerically pure 3-benzazepines 14 and ent-14 were investigated in competitive receptor binding studies. The butyl derivative ent-14c showed a high affinity towards σ1 and σ2 receptors, with Ki-values of 26 nM and 41 nM, respectively. 相似文献