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91.
The influence of chloral hydrate on endosperm cells of Haemanthus katherinae was studied. Four types of mitotic disturbances were described: a) Normal bipolar mitosis with one or few chromosomes lying out of the metaphase plate. Bipolar mitoses are sometimes arrested in anaphase and followed by the formation of a restitution nucleus. b) Tri — or multipolar anaphases. c) Diffuse anaphase movements i.e., active anaphase movements without distinct poles followed by the formation of multipolar phragmoplasts and cell walls. d) C-mitosis resembling the effect of colchicine. Some aspects of the described phenomena were discussed.  相似文献   
92.
It was shown that Botrytis cinerea, an isolate infecting apples, secreted in vivo and in culture a variety of glycosidic hydrolases with substrate specificity towards the polysaccharides of cell walls. The following enzymes were partially separated by column chromatography on DEAE-Sepharose CL-6B: two cellulases, three xylanases, one arabinanase, polygalacturonase, β-glucosidase, β-xylosidase, β-galactosidase, β-mannosidase and α-galactosidase. The activity of glycosidic hydrolases tested was strongly inactivated by NBS and weaker by PCMB, tetranitromethan, dibromoacetophenon and Fe3+, The results indicate synergistic action of the obtained cellulase, xylanase, polygalacturonase and arabinanase in apple cell wall degradation.  相似文献   
93.
As a result of microbial transformation of baicalin and baicalein the products of 4′-hydroxylation of the B ring, O-methylation at C-6, and both O-methylation at C-6 and hydroxylation at C-4′ were obtained. Transformations of baicalin were accompanied by the reaction of hydrolysis.  相似文献   
94.
The aim of this study was to investigate the prevalence of the aacA4 gene in a population of multidrug resistant strains of P. aeruginosa isolated from bronchial secretions obtained from the Intensive Therapy Unit (ITU). Twelve MDR isolates were tested for antibiotic susceptibility and the presence of the aacA4 gene. In this study, 58.3% of the strains contained (6')-Ib' aminoglycoside acetyltransferase gene. All of the studied strains (aacA4-positive and aacA4-negative) were susceptible only to colistine (100%). Among other antibiotics, the lowest resistance rates were those shown against ceftazidime (14.3% to 20%) and imipenem (28.6% to 40%). Our studies frequently revealed the presence of the aacA4 gene as a factor responsible for resistance; it is probable that other mechanisms of resistance to aminoglycoside antibiotics also occurred.  相似文献   
95.
96.
Genistein, due to its recognized chemopreventive and antitumor potential, is a molecule of interest as a lead compound in drug design. While multiple molecular targets for genistein have been identified, so far neither for this isoflavonoid nor for its natural or synthetic derivatives disruption of microtubules and mitotic spindles has been reported. Here we describe such properties of the synthetic glycosidic derivative of genistein significantly more cytotoxic than genistein, 7-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-(1→4)-(6-O-acetyl-hex-2-ene-α-d-erythro-pyranosyl)genistein, shortly named G21. We found that G21 causes significant mitotic delay, frequent appearance of multipolar spindles, and alteration of the interphase microtubule array.  相似文献   
97.
98.
The polyion complex membrane (PEC) composed of chitosan (Ch) and sodium alginate (NaAlg) designated for the separation of water/organic mixtures by pervaporation and/or direct methanol fuel cell technology was synthesized and analysed by FTIR, DSC, DTG and X-ray diffraction. The polyion complex formation between Ch (cationic polyelectrolyte) and NaAlg (anionic polyelectrolyte) was confirmed by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The state of water in pure polyelectrolytes (PE) and PEC was studied by DSC. Results show that freezable and non-freezable water exist in analysed Ch, NaAlg and Ch/NaAlg hydrogels, while there are variations in the amount of non-freezing bound water in PE/water and PEC/water systems. Both ionic crosslinking as well as physical structure influence the state of water, and especially the non-freezable water content, in ionic hydrogel membranes.  相似文献   
99.
The aim of the study was to assess salivary fluoride concentrations and ingestion of fluorides after five different techniques of topical fluoride treatment. Ten volunteers received applications of fluoride gel, toothpaste, and foam. Fluoride concentrations were determined using ion-selective fluoride electrode in the samples of unstimulated saliva before and after procedures. The amounts of fluoride applied, recovered from the mouth, and retained in the mouth were calculated for each treatment. It was proved that fluoride ingestion following tray application of fluoride foam was significantly lower than ingestion following tray applications of fluoride gel (p < 0.01). The use of limited amounts of fluorides on a tray resulted in similar fluoride retention and lower ingestion comparing to the method which involves a large portion of fluorides followed by rinsing. Tooth brushing resulted in high salivary retention rates per amount of fluorides used in the procedure. These data provide initial concept about the possible advantages of some methods of topical fluoride application over others.  相似文献   
100.

Background

Acute exacerbations contribute to the morbidity and mortality associated with chronic obstructive pulmonary disease (COPD). This proof-of-concept study evaluates whether intermittent pulsed moxifloxacin treatment could reduce the frequency of these exacerbations.

Methods

Stable patients with COPD were randomized in a double-blind, placebo-controlled trial to receive moxifloxacin 400 mg PO once daily (N = 573) or placebo (N = 584) once a day for 5 days. Treatment was repeated every 8 weeks for a total of six courses. Patients were repeatedly assessed clinically and microbiologically during the 48-week treatment period, and for a further 24 weeks'' follow-up.

Results

At 48 weeks the odds ratio (OR) for suffering an exacerbation favoured moxifloxacin: per-protocol (PP) population (N = 738, OR 0.75, 95% confidence interval (CI) 0.565-0.994, p = 0.046), intent-to-treat (ITT) population (N = 1149, OR 0.81, 95% CI 0.645-1.008, p = 0.059), and a post-hoc analysis of per-protocol (PP) patients with purulent/mucopurulent sputum production at baseline (N = 323, OR 0.55, 95% CI 0.36-0.84, p = 0.006).There were no significant differences between moxifloxacin and placebo in any pre-specified efficacy subgroup analyses or in hospitalization rates, mortality rates, lung function or changes in St George''s Respiratory Questionnaire (SGRQ) total scores. There was, however, a significant difference in favour of moxifloxacin in the SGRQ symptom domain (ITT: -8.2 vs -3.8, p = 0.009; PP: -8.8 vs -4.4, p = 0.006). Moxifloxacin treatment was not associated with consistent changes in moxifloxacin susceptibility. There were more treatment-emergent, drug related adverse events with moxifloxacin vs placebo (p < 0.001) largely due to gastrointestinal events (4.7% vs 0.7%).

Conclusions

Intermittent pulsed therapy with moxifloxacin reduced the odds of exacerbation by 20% in the ITT population, by 25% among the PP population and by 45% in PP patients with purulent/mucopurulent sputum at baseline. There were no unexpected adverse events and there was no evidence of resistance development.

Trial registration

ClinicalTrials.gov number, NCT00473460 (ClincalTrials.gov).  相似文献   
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