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121.
Bartolomeo Lercari Franco Tognoni Gianni Anselmo Daniele Chapel 《Physiologia plantarum》1986,67(3):340-344
The regeneration of buds from leaves of Saintpaulia ionantha Wendl cv. Sona and from cotyledons of Lycopersicon esculentum Mill. cv. UC 105 was studied in response to continuous light and daily light pulses. The regeneration of buds from cotyledons of Lycopersicon esculentum is high under continuous red and white light. Trie effect of light may be related to phytochrome. In Saintpaulia ionantha blue light appears to be very effective. The experimental results suggest that the blue light effects involve both a blue light absorbing photoreceptor and phytochrome 相似文献
122.
123.
Summary The sporophyte ultrastructure ofTortula muralis
Hedw. has been investigated by scanning and transmission electron microscopy. We have observed the twistings on the surface of the seta, the stomata in the lower part of the capsule and the disposition of cortical, conductive and parenchyma cells in the transversal and longitudinal sections of the seta. Moreover, in transection, the calyptra cells are thick-walled and present structures like tips in front of the epidermis cells of the capsule. Possible meanings of these morphological observations are discussed. 相似文献
124.
Costanza Casiraghi Tatiana Gianni Gabriella Campadelli-Fiume 《Journal of virology》2016,90(8):4243-4248
We report that αvβ3 integrin strongly affects the innate immune response in epithelial cells. αvβ3 integrin greatly increased the response elicited via plasma membrane Toll-like receptors (TLRs) by herpes simplex virus or bacterial ligands. The endosomal TLR3, not the cytosolic sensor interferon gamma-inducible protein 16 (IFI16), was also boosted by αvβ3 integrin. The boosting was exerted specifically by αvβ3 integrin but not by αvβ6 or αvβ8 integrin. Current and previous work indicates that integrin-TLR cooperation occurs in epithelial and monocytic cells. The TLR response should be considered an integrin-TLR response. 相似文献
125.
The secondary structure of two synthetic peptides from heptad-repeat domains of herpes simplex virus 1 glycoprotein H was determined by circular dichroism. In particular, the propensity of these peptides to assume an ordered structure was investigated upon by changing the solvent's polarity and the temperature. A reduction of solvent polarity led to a significant increase in the alpha-helix content in the case of HR1, whereas only a slight change in the secondary structure was observed in the case of HR2. In both cases the conformational change followed a two-state transition model. The interaction of the peptides was monitored by the conformational change in the mixture with respect to the single peptides. However, formation of the complex did not significantly enhance thermal stability. A reliable estimation of the secondary structure was obtained by optimising the experimental conditions to collect CD data down to 180 nm, and by comparing the structure data yielded by different software packages. 相似文献
126.
127.
Gianni Cavinato Luigi Toniolo Lucio Ronchin Alessandro Dolmella 《Inorganica chimica acta》2005,358(15):4555-4562
The title complex has been synthesized by first reacting dppp with Pd(AcO)2 in acetone and then with NaHSO4 in water. It has been characterized by IR, NMR and X-ray diffraction studies. The 31P NMR spectrum in DMSO shows a singlet at 16.62 ppm indicating that the two P atoms are equivalent and that the sulfate anion is weakly coordinating. The X-ray structure shows that the Pd atom is surrounded in an almost regular square planar environment by the two P atoms and by two O atoms of the sulfate anion and that the neutral complex is accompanied by a water molecule of crystallization. The Pd-P distances (2.217(1) and 2.233(1)) and the P-Pd-P angle (90.78(3)°) are close to those found in other complexes where the chelating diphosphine is the same. Also the Pd-O distances and the O-Pd-O bond angle are comparable to those of other relevant chelating ligands.In MeOH, the title complex, in combination with H2SO4, catalyses the CO-ethene copolymerization. The productivity reaches a maximum upon increasing the H2SO4/Pd ratio up to ca. 470 (7650 g of polyketone/g Pd h at 90 °C and 45 atm, CO/ethene 1/1). The viscosity of the polyketone passes through a maximum of 0.95 dL/g in m-cresol when the above ratio is ca. 100. It has been proposed that acid promotes the copolymerization process by destabilizing the β- and γ-chelates intermediates involved in chain growing process, thus favoring the insertion of the monomers. At relatively high acid concentration the lowering of productivity and viscosity suggests that the sulfate anion competes with the monomers for the coordination to the metal center.In H2O-CH3COOH as a solvent the productivity strongly depends on the H2O/CH3COOH ratio, as it passes through a maximum of 12 000 g polymer/g Pd h in the presence of ca. 60% of H2O. The productivity is significantly lower than that found when the acetate and chloride analogues are used (27 000 g polyketone/g Pd · h). Thus, it is likely that the sulfate anion assists significantly the copolymerization process even though the concentration of CH3COOH/CH3COO− is much preponderant. 相似文献
128.
Stefanelli P Colotti G Neri A Salucci ML Miccoli R Di Leandro L Ippoliti R 《IUBMB life》2008,60(9):629-636
The present study evaluates sequence conservation in the gene coding for nitrite reductase (aniA) and AniA expression from a panel of Neisseria meningitidis isolates. Sequence analysis of the coding region in 19 disease-associated and 4 carrier strains notwithstanding a high degree of sequence similarity showed a number of nucleotide changes, some of which possibly resulted in premature translation termination or function loss. In particular, in one disease-associated strain a 9-residues insertion was found to be located close to the type I Cu-site and a catalytic histidine at position 280 was mutated into a leucine. In two strains from carriers, a sequence corresponding to a portion of a transposase gene within the aniA was also found. The AniA protein was always expressed, except for these two carriers strains and for other two strains in which the presence of the premature stop codons was recognized. The biochemical properties of the cloned soluble domain of the enzyme (sAniA) from N. meningitidis reference MC58 strain and from a clinical invasive isolate were studied. In particular, biochemical analysis of sAniA from MC58 demonstrated a clear dependence of its catalytic activity upon acidification, while the clinical isolate-derived sAniA was not functional. Thus, the results obtained suggest that the presence of a conserved and functional aniA gene is not essential for meningococcal survival. 相似文献
129.
Sperandeo P Lau FK Carpentieri A De Castro C Molinaro A Dehò G Silhavy TJ Polissi A 《Journal of bacteriology》2008,190(13):4460-4469
Lipopolysaccharide (LPS) is an essential component of the outer membrane (OM) in most gram-negative bacteria, and its structure and biosynthetic pathway are well known. Nevertheless, the mechanisms of transport and assembly of this molecule at the cell surface are poorly understood. The inner membrane (IM) transport protein MsbA is responsible for flipping LPS across the IM. Additional components of the LPS transport machinery downstream of MsbA have been identified, including the OM protein complex LptD/LptE (formerly Imp/RlpB), the periplasmic LptA protein, the IM-associated cytoplasmic ATP binding cassette protein LptB, and LptC (formerly YrbK), an essential IM component of the LPS transport machinery characterized in this work. Here we show that depletion of any of the proteins mentioned above leads to common phenotypes, including (i) the presence of abnormal membrane structures in the periplasm, (ii) accumulation of de novo-synthesized LPS in two membrane fractions with lower density than the OM, and (iii) accumulation of a modified LPS, which is ligated to repeating units of colanic acid in the outer leaflet of the IM. Our results suggest that LptA, LptB, LptC, LptD, and LptE operate in the LPS assembly pathway and, together with other as-yet-unidentified components, could be part of a complex devoted to the transport of LPS from the periplasmic surface of the IM to the OM. Moreover, the location of at least one of these five proteins in every cellular compartment suggests a model for how the LPS assembly pathway is organized and ordered in space. 相似文献
130.