首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   138篇
  免费   6篇
  国内免费   1篇
  145篇
  2024年   1篇
  2023年   5篇
  2022年   6篇
  2021年   14篇
  2020年   4篇
  2019年   5篇
  2018年   2篇
  2017年   5篇
  2016年   10篇
  2015年   11篇
  2014年   10篇
  2013年   8篇
  2012年   7篇
  2011年   10篇
  2010年   4篇
  2009年   3篇
  2008年   3篇
  2007年   3篇
  2006年   6篇
  2005年   6篇
  2004年   3篇
  2003年   2篇
  2002年   5篇
  1999年   1篇
  1998年   1篇
  1996年   1篇
  1992年   2篇
  1991年   1篇
  1983年   1篇
  1977年   2篇
  1976年   1篇
  1962年   1篇
  1950年   1篇
排序方式: 共有145条查询结果,搜索用时 15 毫秒
91.
OBJECTIVE: The aim of this study was to investigate the effects of different phytosterols and their analogs on colonic mucosal cell proliferation in hamsters. METHOD: Hamsters (n=70) were randomly assigned to seven groups after a 2-week acclimation and fed the experimental diet for 5 weeks. Diets included (i) the semipurified diet with no cholesterol (Con), (ii) the Con diet plus 0.25% cholesterol (Ch-con), or the Ch-con diet with (iii) 1% phytosterols (Ste), (iv) 1% phytostanols (Sta), (v) 1.76% sterol esters (esterified to fish oil, SteF), (vi) 0.71% stanol esters (esterified to ascorbic acid [disodium ascorbyl phytostanol phosphate, FM-VP4], 0.7% StaA) and (vii) 1.43% stanol esters (1.4% StaA), respectively. After 5 weeks on experimental diet, hamsters were sacrificed, and colons were collected. Colonic mucosal cell proliferation was measured by immunohistochemistry using monoclonal antibodies against antigen Ki-67. RESULTS: Colonic mucosal cell proliferation was 21.4% (P<.01) lower in the 0.7%, but not 1.4%, StaA relative to the Ch-con group. In addition, a lower (-13.9%) cell proliferation was observed in the SteF group in comparison to the Ch-con group; however, this difference achieved only a borderline level of statistical significance (P=.069). No differences were observed between Con and Ch-con, as well as among Ste, Sta, 1.4% StaA and Ch-con treatments. CONCLUSION: Plant stanols esterified to ascorbic acid may possess anticarcinogenic properties in the colon by suppressing colonic mucosa cell proliferation; however, this effect was not observed with free plant sterols or stanols.  相似文献   
92.

Background

Infant and young child feeding (IYCF) practices during the first two years of life are important for the growth and development of a child. The aim of this study was to assess IYCF practices and its associated factors in two rural districts of Pakistan.

Methods

A cross-sectional study was conducted in two rural districts of Sindh province, Pakistan as part of a stunting prevention project between May and August 2014. A standard questionnaire on IYCF practices recommended by World Health Organization was used to collect information from 2013 mothers who had a child aged between 0 and 23 months.

Results

Only 49% of mothers initiated breastfeeding within one hour of birth. Thirty-seven percent of mothers exclusively breastfed their infants for six months. Seventy-percent mothers introduced complementary feeding at 6–8 months of age. Eighty-two percent of mothers continued breastfeeding for at least one year and 75% for at least two years of age. IYCF practices were not significantly different for boys and girls in the study area. Being an employed mother (AOR 2.14; 95% CI 1.02, 4.51) was positively associated with the early initiation of breastfeeding. Children who were born at a health facility (AOR 0.65; 95% CI 0.50, 0.84) and were aged six to eleven months (AOR 0.70; 95% CI 0.54, 0.90) were less likely to be have an early initiation of breastfeeding. Mothers aged 25 to 29 years (AOR 1.83; 95% CI 1.05, 3.18), being literate (AOR 1.79; 95% CI 1.15, 2.78), and higher income (AOR 10.6; 95% CI 4.40, 25.30) were more likely to have an improved dietary diversity. Being an employed mother (AOR 2.18; 95% CI 1.77, 4.03) and higher income were more likely to have minimum acceptable diet (AOR 9.7; 95% CI 4.33, 21.71).

Conclusion

IYCF practices were below the acceptable level and associated with maternal age, maternal illiteracy, unemployment, and poor household wealth status. Emphasis should be given to improve maternal literacy and reduction in poverty to improve IYCF practices.
  相似文献   
93.
The liquid and semisolid matrix technology, filling liquids, semi-solids and gels in hard gelatin capsule are promising, thus, there is a need of enhanced research interest in the technology. Therefore, the present study was aimed to investigate isoniazid (freely soluble) and metronidazole (slightly soluble) gels filled in hard gelatin capsules for the effect of poloxamers of different viscosities on release of the drugs. Gel of each drug (10% w/w, particle size 180–250 μm), prepared by mixing poloxamer and 8% w/w hydrophilic silicon dioxide (Aerosil® A200), was assessed for rheology, dispersion stability and release profile. Both the drugs remained dispersed in majority of gels for more than 30 days, and dispersions were depended on gels’ viscosity, which was further depended on viscosity of poloxamers. A small change in viscosity was noted in gels on storage. FTIR spectra indicated no interactions between components of the gels. The gels exhibited thixotropic and shear-thinning behaviour, which were suitable for filling in hard gelatin capsules without any leakage from the capsules. The release of both drugs from the phase-stable gels for 30 days followed first-order kinetics and was found to be correlated to drugs’ solubility, poloxamers’ viscosity, polyoxyethylene contents and proportion of block copolymer (poloxamers) in the gels. The findings of the present study indicated that release of drugs of different solubilities (isoniazid and metronidazole) might be modified from gels using different poloxamers and Aerosil® A200.  相似文献   
94.
95.
A corrole-based chlorophyll analogue has been prepared, based on the notation that the major differences between the prosthetic groups of chlorophylls and hemes are the presence of a non-transition metal (Mg vs. Fe) and one reduced double bond in the porphyrin ligand. As corroles act as tri- rather than dianionic ligands, the analogy requires the insertion of aluminum into the macrocycle and the reduction of one of its double bonds, two reactions that have not been previously reported with any corrole. The aluminum complexes of both the corrole and the corrolin (the dihydrocorrole) display fluorescence quantum yield that are much larger than of chlorophyll and of all other previously reported synthetic analogues. The results suggest that the light metal atom ion is responsible for low intersystem crossing probability to the triplet excited state and the structural rigidity of the hexa-coordinated complexes for reducing the probability of internal conversion.  相似文献   
96.
The detection of human malignancies by near-infrared (NIR) fluorescence will require the conjugation of cancer-specific ligands to NIR fluorophores that have optimal photoproperties and pharmacokinetics. IRDye78, a tetra-sulfonated heptamethine indocyanine NIR fluorophore, meets most of the criteria for an in vivo imaging agent, and is available as an N-hydroxysuccinimide ester for conjugation to low-molecular-weight ligands. However, IRDye78 has a high charge-to-mass ratio, complicating purification of conjugates. It also has a potentially labile linkage between fluorophore and ligand. We have developed an ion-pairing purification strategy for IRDye78 that can be performed with a standard C18 column under neutral conditions, thus preserving the stability of fluorophore, ligand, and conjugate. By employing parallel evaporative light scatter and absorbance detectors, all reactants and products are identified, and conjugate purity is maximized. We describe reversible and irreversible conversions of IRDye78 that can occur during sample purification, and describe methods for preserving conjugate stability. Using seven ligands, spanning several classes of small molecules and peptides (neutral, charged, and/or hydrophobic), we illustrate the robustness of these methods, and confirm that IRDye78 conjugates so purified retain bioactivity and permit NIR fluorescence imaging of specific targets.  相似文献   
97.
98.
Recently the World Health Organization (WHO) has highlighted the need to strengthen mental health systems following emergencies, including natural and manmade disasters. Mental health services need to be informed by culturally attuned evidence that is developed through research. Therefore, there is an urgent need to establish rigorous ethical research practice to underpin the evidence‐base for mental health services delivered during and following emergencies.  相似文献   
99.
100.
Genetic studies have revealed that 25 to 30% of autosomal dominant retinitis pigmentosa (adRP) families have mutations in the rhodopsin gene, while the remainder do not. More recently linkage data and mutation detection have demonstrated two further loci implicated in adRP, at an as yet unidentified gene on chromosome 8p and at the human gene homologue of the mouse Rds (Retinal Degeneration Slow) gene on chromosome 6p. We have previously reported exclusion of adRP from the rhodopsin locus on 3q in two large adRP families. We now report exclusion data for both families, on chromosomes 6 and 8, demonstrating that the adRP phenotype results from mutations in at least four locations.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号