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91.
92.
Siwek A Stączek P Wujec M Stefańska J Kosikowska U Malm A Jankowski S Paneth P 《Journal of molecular modeling》2011,17(9):2297-2303
4-Benzoyl-1-(4-methyl-imidazol-5-yl)-carbonylthiosemicarbazide (1) was synthesized, and its antibacterial and type IIA topoisomerase (DNA gyrase and topoisomerase IV) activity evaluated.
(1) was found to have high therapeutic potential against opportunistic Gram-positive bacteria, and inhibitory activity against
topoisomerase IV (IC50 = 90 μM) but not against DNA gyrase. An increase in activity against topoisomerase IV (IC50 = 14 μM) was observed when the imidazole moiety of (1) was replaced with the indole group in 4-benzoyl-1-(indol-2-yl)-carbonylthiosemicarbazide (2). However, (2) showed only weak antibacterial activity. Although the results of the bacterial type IIA topoisomerases inhibition study
did not parallel antibacterial activities, our observations strongly imply that a 4-benzoylthiosemicarbazide scaffold can
be developed into an efficient Gram-positive antibacterial targeting topoisomerase IV. The difference in activity against
type IIA topoisomerases between (1) and (2) was further investigated by docking studies, which suggested that these compounds target the ATP binding pocket. 相似文献
93.
An optimal control problem for cancer chemotherapy is considered that includes immunological activity. In the objective a
weighted average of several quantities that describe the effectiveness of treatment is minimized. These terms include (i)
the number of cancer cells at the terminal time, (ii) a measure for the immunocompetent cell densities at the terminal point
(included as a negative term), (iii) the overall amount of cytotoxic agents given as a measure for the side effects of treatment
and (iv) a small penalty on the terminal time that limits the overall therapy horizon which is assumed to be free. This last
term is essential in obtaining a well-posed problem formulation. Employing a Gompertzian growth model for the cancer cells,
for various scenarios optimal controls and corresponding responses of the system are calculated. Solutions initially follow
a full dose treatment, but then at one point switch to a singular regimen that only applies partial dosages. This structure
is consistent with protocols that apply an initial burst to reduce the tumor volume and then maintain a small volume through
lower dosages. Optimal controls end with either a prolonged period of no dose treatment or, in a small number of scenarios,
this no dose interval is still followed by one more short burst of full dose treatment. 相似文献
94.
Janecka A Fichna J Kosson P Zalewska-Kaszubska J Krajewska U Mirowski M Rozalski M 《Regulatory peptides》2004,120(1-3):237-241
In the present study, we reported on the synthesis of two new mu-opioid peptide analogs, [D-1-Nal3]morphiceptin and [D-1-Nal4]-morphiceptin [1-Nal=3-(1-naphthyl)-alanine] which expressed receptor binding affinities at least at the level of the primary opioid ligands. The new analogs also labeled mu-opioid receptors on the cells of human breast cancer MCF-7 cell line with affinity much higher than that of endomorphins and morphiceptin, the well-known mu-selective opioid peptides. However, none of the tested peptides significantly decreased cell proliferation of MCF-7 cells. 相似文献
95.
Januszkiewicz A Podsiadły E Szych J Semkowicz-Chmielewska A Demkow U Pierzchlewicz A Rastawicki W 《Medycyna do?wiadczalna i mikrobiologia》2010,62(4):319-330
Shiga toxin-producing E. coli O157 and non-O157 are important emergance pathogens that can cause diarrhea and hemorrhagic colitis with life-threatening complications, such as hemolytic uremic syndrome (HUS). A few cases of EHEC infections are documented per year in Poland. Among them only one patient with EHEC O157 infection developed HUS. We characterized the first VTEC non-O157 strain isolated from child with HUS in Poland. The VTEC O111 strain produced Stx2 which was cytotoxic for Vero cell. Using DNA microarray analysis we have found set of virulence genes in VTEC O111 strain as: stx2A, stx2B, ehly, eae, tir tccP espA, espJ, cif nleA, nleB, lpfA, iha, efa1, cba. The strain was fenotypic resistant to streptomycin, tetracyclin and sulphonamides (strA, tetA, sul2 genes were detected). 相似文献
96.
Carbon and nitrogen stable isotope ratios were measured in hair samples from two species of Galago from Gedi Ruins National Monument in eastern Kenya and from Lepilemur leucopus from Beza Mahafaly Special Reserve in southern Madagascar. Forest structure was generally similar in the two areas but average
rainfall was lower in Madagascar. Species average 13C values varied with feeding height in the forest canopy and with average rainfall level as expected from reported variation
in plant 13C values. G. garnettii, which feeds higher in the forest canopy, had less negative 13C values than G. zanzibaricus, which spends more time below 5 m. L. leucopus, from a drought-afflicted forest, had less negative hair 13C values than the two galago species. The values within the Lepilemur sample showed a positive linear relation with percent dependence on a CAM tree species and with xeric conditions within the
species reserve. Nitrogen stable isotope ratios varied with trophic level of feeding and with time spent feeding on leguminous
plants. The insectivorous galagos had significantly more positive 15N values than the folivorous L. leucopus. Within the Lepilemur sample, 15N values varied inversely with the percent of feeding time spent on leguminous plants. The range of 15N and 13C values in each of the prosimian species is larger than reported for animals fed monotonous diets and for New World monkey
species. The monkey species feed as groups of individuals whereas the prosimians have solitary feeding habits. The ranges
in the prosimian species apparently reflect the greater variation in diet among individual prosimians compared to individual
monkeys. The isotope data reported here are equivalent, on average, to those reported for other arboreal species from similar
forest habitats and with similar dietary habits. This supports the use of such data for paleoecological reconstruction of
forest and woodland systems and diet reconstruction of extinct primate populations and species.
Received: 18 April 1997 / Accepted: 11 August 1997 相似文献
97.
In this study, we attempted to determine the role of GABA neurotransmission in augmentation of hypoxic respiration by antecedent hyperoxic breathing. The experiments were performed in anesthetized, paralyzed and vagotomized cats divided into control and bicuculline (a GABAA receptor blocker)-injected groups. The experimental protocol consisted of exposing the animals to successive hypoxic-hyperoxic-hypoxic conditions. Respiration was assessed using phrenic electroneurograms, from which the peak phrenic height, a surrogate of the tidal volume component, and respiratory rate were obtained, and their product, the respiratory minute output, was calculated. We found that prior hyperoxic ventilation increased the subsequent respiratory response to hypoxia by an average of 23.5%, compared with the preoxygen response. This increase was driven by volume respiration. The biphasic character of the hypoxic respiratory response, consisting of stimulatory and depressant phases, was sustained. Bicuculline abolished the augmentative effect on hypoxic respiration of prior hyperoxia, which suggests that oxygenation induces GABAA-mediated hyperexcitability of respiratory neurons, possibly by the liberation of reactive oxygen species. We concluded that GABA neurotransmission is pertinent to the effect of hyperoxia on hypoxic respiratory reactivity. 相似文献
98.
Nowak R Gawlik-Dziki U 《Zeitschrift für Naturforschung. C, Journal of biosciences》2007,62(1-2):32-38
Antioxidant potential of Rosa L. leaves methanolic extracts was evaluated in vitro using a spectrophotometric method based on measuring the radical scavenging effect on 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radicals. The contents of ellagic acid, quercetin and kaempferol in the extracts from leaves of seventeen rose species were determined using SPE-RP-HPLC methods. Additionally, total phenolic content was determined spectrophotometrically according to the Folin-Ciocalteu procedure and calculated as gallic acid equivalents (GAE). Remarkable high antioxidant activity and high total phenolic content (5.7% < GAE < 15.2%), large ellagic acid (EA) content from 9.37 to 19.42 mg/g of dry weight, a quercetin content ranging from 3.68 to 15.81 mg/g of dry weight and kaempferol content from 1.25 to 9.41mg/g of dry weight were found in rose leaves. Significant correlation between EA (r(2) = 0.6131), quercetin (r(2) = 0.5158), total phenolic content (r(2)= 0.8485) and antioxidant activity was observed. Basing on the studies conducted one may assume that the extracts of rose leaves are a rich source of natural antioxidants and could be used to prevent free-radical-induced deleterious effects. 相似文献
99.
Katarzyna Robak Maria Balcerek Urszula Dziekońska-Kubczak Piotr Dziugan 《Biotechnology progress》2019,35(3):e2789
This research shows the effect of dilute acid pretreatment with various sulfuric acid concentrations (0.5–2.0% [wt/vol]) on enzymatic saccharification and fermentation yield of rye straw. After pretreatment, solids of rye straw were suspended in Na citrate buffer or post-pretreatment liquids (prehydrolysates) containing sugars liberated after hemicellulose hydrolysis. Saccharification was conducted using enzymes dosage of 15 or 25 FPU/g cellulose. Cellulose saccharification rate after rye straw pretreatment was enhanced by performing enzymatic hydrolysis in sodium citrate buffer in comparison with hemicellulose prehydrolysate. The maximum cellulose saccharification rate (69%) was reached in sodium citrate buffer (biomass pretreated with 2.0% [wt/vol] H2SO4). Lignocellulosic complex of rye straw after pretreatment was subjected to separate hydrolysis and fermentation (SHF) or separate hydrolysis and co-fermentation (SHCF). The SHF processes conducted in the sodium citrate buffer using monoculture of Saccharomyces cerevisiae (Ethanol Red) were more efficient compared to hemicellulose prehydrolysate in respect with ethanol yields. Maximum fermentation efficiency of SHF processes obtained after rye straw pretreatment at 1.5% [wt/vol] H2SO4 and saccharification using enzymes dosage of 25 FPU/g in sodium citrate buffer, achieving 40.6% of theoretical yield. However, SHCF process using cocultures of pentose-fermenting yeast, after pretreatment of raw material at 1.5% [wt/vol] H2SO4 and hydrolysis using enzymes dosage of 25 FPU/g, resulted in the highest ethanol yield among studied methods, achieving 9.4 g/L of ethanol, corresponding to 55% of theoretical yield. 相似文献
100.