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71.
Dirk J. A. De Ridder Kees Goubitz Ed J. Sonneveld Wim Molleman Henk Schenk 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):m596-m598
The structure of lead tartrate, Pb2+·C4H4O62?, has been solved from X‐ray powder diffraction data. The cation exhibits ninefold coordination and the tartrate groups are linked through Pb?O contacts to form a three‐dimensional network. 相似文献
72.
Mihaela Pop Gheorghe Borodi Kees Goubitz Ren Peschar Jan Fraanje Ioan Fenesan Henk Schenk 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):o280-o281
The title compound, C11H17N2O3PS2, is a cyclic thiophosphoryl pyrimidine derivative exhibiting insecticidal properties. The crystal structure determination gives evidence for the presence of the thione isomer of the compound. The pyrimidine nucleus is planar and its substituents have small deviations from the least‐squares plane. The dioxaphosphorinane ring adopts a chair conformation. The lack of classical hydrogen bonds and the weak intermolecular interactions lead to a `loose' packing characterized by channels in the structure. 相似文献
73.
Gabeler EE Sluiter W van Hillegersberg R Edixhoven A Schoonderwoerd K Statius van Eps RG van Urk H 《Photochemistry and photobiology》2003,78(1):82-87
Photodynamic therapy (PDT) based on the photosensitive protoporphyrin IX (PpIX) may prevent restenosis after transluminal angioplasty. PpIX is synthesized in mitochondria, which differ in number and activity among various tissues. Therefore, we questioned whether the course of PpIX concentration after systemic aminolaevulinic acid (ALA) administration differed among various arteries. ALA was administered intravenously (200 mg/kg) to male Wistar rats (n = 21). At varying time intervals (0, 1, 2, 3, 6, 12 and 24 h) both central and peripheral arteries were isolated and homogenized, and the concentration of the various heme intermediates was determined by a fluorometric extraction method. The maximal PpIX concentration was more than two-fold higher in peripheral arteries (20.49 +/- 3.0 to 24.0 +/- 7.5 pmol/mg protein) than in central arteries (0-9.46 +/- 0.01 pmol/mg protein) (P < 0.004). However, the amount of citrate synthase, reflecting the mitochondrial mass, was lower (0.14-0.61 and 1.87-2.32 U/mg protein, respectively). Apparently, the level of PpIX cannot simply be explained by the mitochondrial content of the arteries. The time interval of maximal PpIX accumulation was similar in peripheral and central arteries (2 h and 27 min vs. 2 h and 8 min) (P = 0.13). Thus, if the efficacy of PDT in vivo is directly related to the tissue concentration of PpIX, more effect can be expected in peripheral arteries than in central arteries. 相似文献
74.
Boone CM Manetto G Tagliaro F Waterval JC Underberg WJ Franke JP de Zeeuw RA Ensing K 《Electrophoresis》2002,23(1):67-73
An interlaboratory pilot study was performed to determine the reproducibility of mobility parameters in capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC). The study was performed by an intended small number of laboratories (three) that used different brands of instruments (two). The effective mobility was corrected using standards by a method that was recently introduced to obtain a more reproducible migration parameter. A test set of 20 acidic test compounds and 5 reference compounds were analyzed during five days in each laboratory using CZE and MEKC. Buffers used consisted of 90 mM borate set at pH 8.4 (CZE) and 20 mM phosphate, 50 mM sodium dodecyl sulfate set at pH 7.5 (MEKC). Analyses were carried out using fused-silica capillaries at an electric field strength of either 52.6 kV/m or 37.5 kV/m. The interlaboratory reproducibility (mean RSD) of the effective mobility was 3.0% for CZE and 6.7% for MEKC. After applying the correction method, these values became 3.0% for CZE and 3.3% for MEKC, which is adequate for systematic toxicological analysis (STA) applications. A significant improvement of reproducibility for the calculated corrected effective mobility mu(eff)c was observed when variations are high. Therefore, it is recommended to use the correction method in interlaboratory situations, especially when instruments and capillaries from different manufacturers are used. 相似文献
75.
Blomgren A Berggren C Holmberg A Larsson F Sellergren B Ensing K 《Journal of chromatography. A》2002,975(1):157-164
A method for the extraction of clenbuterol from calf urine samples using a molecularly imprinted polymer (MIP) has been developed. The aim was that the final extracts from the MIP should allow quantitation of clenbuterol down to 0.5 ng/mL urine using HPLC with UV detection. The MIP was produced using brombuterol as a template and the selectivity of the MIP, for clenbuterol, was tested against a non-imprinted polymer (produced without template) and was found to be high. After loading of 5 mL diluted centrifuged urine, selective binding was established in acetonitrile-acetic acid (98:2). For further elution of interferences, 0.5 M ammonium acetate buffer pH 5 and 70% acetonitrile in water was used. Clenbuterol was eluted using 1% trifluoroacetic acid in methanol, which was evaporated and reconstituted in buffer. Results from the HPLC analyses showed that the extraction of clenbuterol using MIP is linear in the range 0.5-100 ng/mL with good precision (4.3% for 0.6 ng/mL and 2.1% for 6.0 ng/mL) and accuracy (96.7% for 0.6 ng/mL and 96.7% for 6.0 ng/mL). The recoveries were 75%. The results show that the method offers a selectivity and sensitivity that make the quantitation of 0.5 ng clenbuterol/mL urine by HPLC-UV possible and a competitive alternative to state-of-the-art routine analytical methods. 相似文献
76.
Johann T. B. H. Jastrzebski Johannes M. Klerks Gerard van Koten Kees Vrieze 《Journal of organometallic chemistry》1981,210(3):C49-C53
Whereas p-Tol2Zn reacts with t-BuN=CHCH=N-t-Bu (t-BuDAB) to give a stable
complex [p-Tol2Zn(t-BuDAB)], Et2Zn gives EtZ
-(t-Bu) via intramolecular ethyl transfer in the unstable Et2Zn(t-BuDAB) complex. In solution the stable persistent organozinc radical EtZn(t-BuDAB), which is formed in trace amounts in the Et2Zn/t-BuDAB reaction, is in equilibrium with its stable C---C coupled dimer [EtZn-t-BuN=CH(t-BuN)CH]2. The dimer can be prepared in quantitative yield by the reaction of (EtZnCl)4 with K(t-BuDAB). 相似文献
77.
Aihara H Alston-Garnjost M Avery RE Barbaro-Galtieri A Barker AR Barnes AV Barnett BA Bauer DA Bengtsson H Bintinger DL Blumenfeld BJ Bobbink GJ Bross AD Buchanan CD Buijs A Cain MP Caldwell DO Chamberlain O Chien C Clark AR Cowan GD Crane DA Dahl OI Derby KA Eastman JJ Eberhard PH Eisner AM Enomoto R Erne FC Fujii T Gabioud B Gary JW Gorn W Hauptman JM Hofmann W Huth JE Hylen J Joshi UP Kamae T Kaye HS Kees KH Kenney RW Kerth LT Ko W Koda RI Kofler RR Kwong KK Lander RL Langeveld WG Layter JG 《Physical review letters》1986,57(1):51-54
78.
Jan Keijsper Henk Van Der Poel Louis H. Polm Gerard Van Koten Kees Vrieze Paul F.A.B. Seignette Ronald Varenhorst Caspar Stam 《Polyhedron》1983,2(11):1111-1116
The crystal and molecular structures of c-Hex-DAB (c-hexyl-NC(H)C(H)N-c-hexyl; DAB = 1,4-diaza-1,3-butadiene) and of trans-[PdCl2(PPh3)(t-Bu-DAB)] are reported. Crystals of c-Hex-DAB are monoclinic with space group C2/c and cell constants: a = 24.70(1), b = 4.660(2), c = 12.268(3)Å, β = 107.66(4)°, Z = 4. The molecule has a flat E-s-trans-E structure with bond lengths of 1.258(3)Å for the CN double bond and 1.457(3)Å for the central CC′ bond. These bond lengths and the NC-C′ angle of 120.8(2)° indicate that the C- and N-atoms are purely sp2-hybridized and that there is little or no conjugation within the central DAB skeleton. Crystals of trans-[PdCl2(PPh3)(t-Bu-DAB)] are triclinic with space group P-1 and cell constants: a = 17.122(3), b = 18.279(3), c = 10.008(5)Å, α = 96.77(2), β = 95.29(3), γ = 109.79(2). Z = 4. The t-Bu-DAB ligand is coordinated to the metal via one lone pair only. In this 2e; σ-N coordination mode the E-s-trans-E conformation of the free DAB-ligand is still present and the bonding distances within the DAB-ligand are hardly affected. [CN: 1.261(10)Å; CC′: 1.479(10)Å (mean).] The PdN-, NC- and central CC′-bond lengths are compared with those found in other metal -R-DAB complexes. 相似文献
79.
Summary The platinum-platinum bonded [PtR2(OAc)L1]2 complexes (R = Ph, L1 = Et2S, n-Pr2S; R =p-tolyl, L1 = Et2S), have been prepared by oxidising [PrR2L1 ]2 with AgOAc or Tl(OAc)3. The sulphide ligand is replaced by weak ligands to give [PtR2(OAc)L2]2 (L2 = PhNH2, 4-picoline, CI–) whereas PEt3 or P(OMe)3 react to give Pt2R4(OAc)2(PR3)(R = Et, OMe). The methyl platinum analogues could also be prepared. Similar complexes Pt2Me4(O2CCF3)2L3 (L3 = Et2S1 4-picoline) were obtained by the reaction of Hg(O2CCF3)2 with [PtMe2(O2CCF3)L3]2.31p,1H and13C n.m.r. of the complexes are reported. 相似文献
80.
Aihara H Alston-Garnjost M Armitage JC Bakken JA Barbaro-Galtieri A Barker AR Barnes AV Barnett BA Bengtsson H Bintinger DL Blumenfeld BJ Bobbink GJ Bross AD Buchanan CD Buijs A Cain MP Caldwell DO Chamberlain O Chien C Clark AR Cordier A Dahl OI Day CT Derby KA van Driel MA Eberhard PH Eisner AM Erné FC Fancher DL Fujii H Fujii T Gabioud B Gary JW Gorn W Hadley NJ Hauptman JM Hofmann W Huth JE Hylen J Joshi UP Kamae T Kaye HS Kees KH Kenney RW Kerth LT Ko W Koda RI Kofler RR Kwong KK 《Physical review letters》1985,54(24):2564-2567