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81.
82.
Daniela Polag Lutz Christian Krapf Hauke Heuwinkel Stephan Laukenmann Jos Lelieveld Frank Keppler 《Engineering in Life Science》2014,14(2):153-160
Efficient operation and stability of biogas plants requires continuous monitoring of the digester content. Traditional laboratory analysis of digester sludge is often complex and time‐consuming and shows a delayed response to disruptions within the fermentation process. As a new approach, we applied an online measurement technique (laser absorption spectroscopy) for real‐time monitoring of stable carbon isotopes of methane () in a pilot‐scale biogas digester (3500 L) regularly fed with maize silage. Generally, isotopic composition of methane gives information about specific substrate degradation, that is, methanogenic pathways that reflect the actual digester state. First results of a 2‐wk monitoring experiment show that stable carbon isotopes of methane respond promptly and highly dynamic to changes in the process state of the digester. In combination with other monitoring parameters (methane production rate, concentration of volatile fatty acids, and pH) the fluctuations in can be interpreted as a change in methanogenic pathways due to a high organic loading rate. In this context, might be used as a new parameter tool for monitoring and characterization of the process state of the digester. 相似文献
83.
Buss I Garmann D Galanski M Weber G Kalayda GV Keppler BK Jaehde U 《Journal of inorganic biochemistry》2011,105(5):709-717
Decreased influx represents one of the major resistance mechanisms of platinum complexes. In order to address the question if this mechanism of resistance can be overcome by enhancing the lipophilicity of platinum complexes, we investigated the influence of lipophilicity on cellular accumulation and cytotoxicity in a panel of oxaliplatin analogues with different carrier ligands. Cellular accumulation, DNA platination and cytotoxicity were measured in a cisplatin-sensitive and -resistant ovarian carcinoma (A2780/A2780cis) and in an oxaliplatin-sensitive and -resistant ileocecal colorectal adenocarcinoma (HCT-8/HCT-8ox) cell line pair. Platinum concentrations were determined by flameless atomic absorption spectrometry or adsorptive stripping voltammetry. Passive diffusion represented the main influx mechanism of oxaliplatin analogues during the first minutes of incubation as indicated by a correlation between lipophilicity and early influx rate. Afterwards, the predominant influx mechanism was lipophilicity-independent. More lipophilic complexes showed a reduced cytotoxic activity, although the early influx rate was increased. The resistance profiles of the two cell line pairs were found to be different: HCT-8ox cells were less resistant against more lipophilic complexes, whereas A2780cis cells exhibited a comparable degree of resistance against all investigated compounds. However, the reduction in resistance factor of HCT-8ox cells cannot be explained by increased influx suggesting that other resistance mechanisms are circumvented upon exposure to more lipophilic compounds. Though resistance against more lipophilic platinum complexes analogues is lower we conclude that enhancing lipophilicity is not a successful strategy to overcome platinum resistance as higher lipophilicity is also associated with lower cytotoxic activity. 相似文献
84.
Song J Jie C Polk P Shridhar R Clair T Zhang J Yin L Keppler D 《Biochemical and biophysical research communications》2006,340(1):175-182
85.
The intravenous administration of [3H]leukotriene C4 in the monkey Macaca fascicularis results in the biliary and urinary elimination of [3H]leukotriene D4 and [3H]leukotriene E4 in addition to more-polar metabolites. Separation of these polar metabolites and chromatographic comparison with synthetic w-oxidized leukotrienes indicated the in vivo formation of w-hydroxy-[3H]leukotriene E4 and w-carboxy-[3H]leukotriene E4. Time course studies of the [3H]leukotriene metabolite pattern in bile and urine showed that w-hydroxy-leukotriene E4 was decreasing as w-carboxy-leukotriene E4 and additional polar derivatives were increasing. 相似文献
86.
Mennah-Govela Yamile A. Keppler Silvia Januzzi-Guerreiro Felipe Follador-Lemos Camila Vilpont Karine Bornhorst Gail M. 《Food biophysics》2020,15(2):261-272
Food Biophysics - Acid and moisture diffusion into foods during digestion influence food breakdown and nutrient release. As these mass transport processes can be affected by gastric pH and initial... 相似文献
87.
Hartinger CG Zorbas-Seifried S Jakupec MA Kynast B Zorbas H Keppler BK 《Journal of inorganic biochemistry》2006,100(5-6):891-904
Indazolium trans-[tetrachlorobis(1H-indazole)ruthenate(III)] (KP1019 or FFC14A) is just the second ruthenium-based anticancer agent after NAMI-A which was developed to the stage of clinical trials. Important steps in the mode of action of KP1019 are thought to be the binding to the serum protein transferrin and the transport into the cell via the transferrin pathway. Additionally, the selective activation by reduction in the tumor might contribute to the low side effects observed in in vivo studies. Apoptosis is induced at non-toxic levels via the mitochondrial pathway. These features distinguish it from the established platinum anticancer drugs and suggest that different types of cancer might be treatable with this drug. Indeed, promising activity against certain types of tumors, which are not successfully treatable with cisplatin, and only a very low incidence of acquired resistance has been observed in in vitro and in vivo studies. Recently, a clinical phase I trial was finished in which none of the treated patients experienced serious side effects, while disease stabilization in five of six evaluable patients was achieved. In this review, the preclinical and early clinical development of KP1019 - from bench to bedside - is recapitulated. 相似文献
88.
Two platinum(IV) complexes (OC-6-33)-dichlorido(ethane-1,2-diamine)dihydroxidoplatinum(IV) and (OC-6-33)-diammine(dichlorido)dihydroxidoplatinum(IV) were carboxylated using demethylcantharidin as carboxylation agent. The complexes were characterized by elemental analysis, mass spectrometry, multinuclear (1H, 13C, 15N, and 195Pt) NMR spectroscopy, and, in case of (OC-6-33)-diamminebis(3-carboxy-7exo-oxabicyclo[2.2.1]heptane-2-carboxylato)dichloridoplatinum(IV) via X-ray diffraction. Cytotoxicity of the complexes was studied in seven human cancer cell lines representing five tumor entities, i.e., ovarian carcinoma (CH1, SK-OV-3), cervical carcinoma (HeLa), colon carcinoma (SW480, HCT-116), osteosarcoma (U-2 OS), and hepatocellular carcinoma (Hep G2) by means of the MTT (=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium hydrobromide) assay. 相似文献
89.
Scolaro C Hartinger CG Allardyce CS Keppler BK Dyson PJ 《Journal of inorganic biochemistry》2008,102(9):1743-1748
The hydrolysis of [Ru(η6-p-cymene)Cl2(PTA)] (PTA = 1,3,5-triaza-7-phosphatricyclo-[3.3.1.1]decanephosphine; RAPTA-C) was studied using UV-visible (UV-vis) spectrophotometry and NMR spectroscopy. In analogy to in silico studies, [Ru(η6-p-cymene)Cl(H2O)(PTA)]+ was found to be the most abundant hydrolysis product, although the dihydrolysed species [Ru(η6-p-cymene)(OH)(H2O)(PTA)]+ and the dichloro compound are present. Rate constants for the different aquation and anation steps and the equilibrium constants were determined. Hydrolysis is suppressed at high chloride concentrations. These results have important implications on the mode of action of the RAPTA drug candidates. 相似文献
90.
A recently silenced, duplicate PgiC locus in Clarkia 总被引:1,自引:0,他引:1
Previous electrophoretic analysis showed that 17 diploid species of the
wildflower Clarkia (Onagraceae) have two cytosolic isozymes of
phosphoglucose isomerase (PGIC; EC 5.3.1.9), whereas 15 other diploid
species have a single PGIC. Molecular studies revealed that the two
isozymes in the former species are encoded by duplicate genes, PgiC1 and
PgiC2, whereas the single isozyme in the latter is always encoded by PgiC1.
Phylogenetic analysis of the nucleotide sequences implied that PgiC2 was
silenced four times independently in the genus. Here we describe a psi
PgiC2 from C. mildrediae, a species in which only PgiC1 is expressed. The
discovery of the psi PgiC2 is significant because it confirms a formal
prediction of the phylogenetic analysis. The psi PgiC2 includes 5,039
nucleotides corresponding to 18 of the 23 exons of PgiC, as well as the
intervening introns and 3' nontranslated region. The absence of an increase
of nucleotide substitutions in its "exons" suggests that the gene was
silenced recently. The present study appears to be the first to establish
that a specific duplicate gene locus regularly expressed in a group of
related plant species has been silenced in one of them. The multiple
independent silencings of PgiC2 suggest that it remained functional but
inessential in ancestral lineages. We discuss the possibility that PgiC2
may have been preserved in these lineages by selection against mutants
causing defective PGIC1- PGIC2 heterodimers.
相似文献