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   94篇
  免费   1篇
  2023年   1篇
  2022年   3篇
  2020年   4篇
  2019年   4篇
  2018年   1篇
  2017年   4篇
  2016年   1篇
  2015年   5篇
  2014年   2篇
  2013年   1篇
  2012年   8篇
  2011年   11篇
  2010年   7篇
  2009年   4篇
  2008年   8篇
  2007年   4篇
  2006年   9篇
  2005年   6篇
  2004年   6篇
  2003年   3篇
  2002年   3篇
排序方式: 共有95条查询结果,搜索用时 656 毫秒
61.
Papaya is a climacteric fruit in which ripening is greatly regulated by ethylene often associated with stress responses such as wounding. The changes in cell wall compositions in papaya fruit at an advanced stage of ripening under stress conditions including chilling temperature of 5°C and wounding employed as fresh-cut and how these changes were affected by an ethylene action inhibitor of 1-methylcyclopropopene (1-MCP) were examined in the study. The recovery of ethanol-insoluble solids, total soluble sugars, water-soluble polyuronides, neutral hemicelluloses, and neutral sugars of rhamnose, arabinose, mannose and glucose were not affected by 1-MCP or fresh-cut processing. The fresh-cut processing, however, caused a higher loss of total polyuronides and the neutral sugar galactose while increasing the recovery of chelator-soluble polyuronides. Few significant differences due to 1-MCP application were recorded in the recoveries of alkali-soluble polyuronides, hemicellulosic polyuronides extracted with 4% KOH, and the neutral sugar xylose. Modifications of cell wall polyuronides and hemicelluloses in ripe fresh-cut papaya fruit exhibited mostly similar patterns to those in intact ripe papaya fruit under the chilling temperature of 5°C while minimally affected by 1-MCP.  相似文献   
62.
doi: 10.1111/j.1741‐2358.2010.00363.x
General health, dental status and perceived dental treatment needs of an elderly population in Istanbul Background: Comprehensive data on the oral health status and dental treatment needs of the elderly population in Turkey are deficient. Objectives: This pilot study determined the general and dental health status, perceived medical and dental treatment needs of an elderly population dwelling in residential homes in Istanbul. Method: Subjects at three different residential homes, namely one belonging to the state and two supported by foundations in Istanbul (N=121, female: 63 and male: 58) were involved in this study. A detailed questionnaire was prepared and dental examinations were conducted. Information was collected related to age, education levels, financial status, current physical functional status, general health, mental health, previous dental history, current dental status, oral hygiene practices and denture hygiene of these elderly people. The prevalence of edentulism, the presence and type of dental prostheses, dental and denture status and denture cleanliness were further evaluated. Results: The three most prevalent reported general health problems were associated with genito‐urinary problems (24%) followed by cardiovascular (18%) and respiratory problems (14%) varying significantly between genders, with males suffering more from cardiovascular problems than females (p < 0.05). Females showed significantly higher gastrointestinal and orthopaedic problems than males (p < 0.05). Females were more frequently edentulous than males but denture hygiene was significantly better in females than in males (p < 0.05). Brushing frequency did not significantly increase denture hygiene (p = 0.6). More than one‐third of the subjects had not been to the dentist within the previous 5–10 years, mainly due to lack of demand, followed by the cost of the dental care and fear. More than two‐thirds of denture‐wearing subjects wore their dentures only during eating. Conclusions: There was significant perceived dental treatment and care need for the sample population of elderly studied.  相似文献   
63.
Preimplantation genetic diagnosis is a preventive approach for identifying genetic abnormalities in early stages of reproduction. We used preimplantation genetic aneuploidy screening in 230 cycles of patients with indications of advanced maternal age, recurrent implantation failure, recurrent spontaneous abortions, or severe male factor. Biopsied blastomeres from embryos with six to eight blastomeres on day 3 were fixed and fluorescence in situ hybridization was utilized on chromosomes 13, 16, 18, 21, 22, X, and Y. Among 945 morphologically normal embryos, 314 were diagnosed as chromosomally normal. Trisomy and monosomy were observed in 36% of the cases (18% each). Embryo transfer was used in 144 cycles, resulting in 41 pregnancies. Thirty-seven healthy babies were delivered, with a take-home baby rate of 24.2% and an implantation rate of 22%. We recommend preimplantation genetic aneuploidy screening as a valuable technique to select normal chromosome embryos in order to avoid multiple pregnancies due to the multiple embryo transfers that are normally necessary to ensure pregnancy in poor prognosis in vitro fertilization patients.  相似文献   
64.
SecB is a homotetrameric cytosolic chaperone that forms part of the protein translocation machinery in E. coli. Due to SecB, nascent polypeptides are maintained in an unfolded translocation-competent state devoid of tertiary structure and thus are guided to the translocon. In vitro SecB rapidly binds to a variety of ligands in a non-native state. We have previously investigated the bound state conformation of the model substrate bovine pancreatic trypsin inhibitor (BPTI) as well as the conformation of SecB itself by using proximity relationships based on site-directed spin labeling and pyrene fluorescence methods. It was shown that SecB undergoes a conformational change during the process of substrate binding. Here, we generated SecB mutants containing but a single cysteine per subunit or an exposed highly reactive new cysteine after removal of the nearby intrinsic cysteines. Quantitative spin labeling was achieved with the methanethiosulfonate spin label (MTS) at positions C97 or E90C, respectively. Highfield (W-band) electron paramagnetic resonance (EPR) measurements revealed that with BPTI present the spin labels are exposed to a more polar/hydrophilic environment. Nanoscale distance measurements with double electron-electron resonance (DEER) were in excellent agreement with distances obtained by molecular modeling. Binding of BPTI also led to a slight change in distances between labels at C97 but not at E90C. While the shorter distance in the tetramer increased, the larger diagonal distance decreased. These findings can be explained by a widening of the tetrameric structure upon substrate binding much like the opening of two pairs of scissors.  相似文献   
65.
Human orf is a viral zoonotic infection caused by Parapoxvirus. The skin lesions of human orf can be misdiagnosed as cutaneous anthrax leading to overtreatment and also fear. This study was conducted to analyze an outbreak which led to deaths among kids and lambs in the same flock, and skin lesions in some persons who were living on the same farm that were initially diagnosed as cutaneous anthrax by a practitioner. Eight patients with skin lesions and eleven persons who had no skin lesion were considered as patients and control groups, respectively. The cultures obtained from the lesions of all patients were negative for Bacillus anthracis. The diagnosis of skin lesions was done by clinical findings, histopathological examination and PCR as human orf. To be under 20 years of age, direct contact with the animals, and contact with flayed skin of sick animals were the risk factors for human orf (Odds Ratio 7.5; 95% Confidence Interval 1.02-54.54, OR 12.25; 95% CI:1.3-100.9, OR 16.67; 95% CI:1.65-148.20, respectively). Orf should be kept in mind in the differential diagnosis of skin lesions resembling anthrax. For control and prevention of orf, transmission routes should be known; good hand hygiene and other personal protective measures have to be implemented.  相似文献   
66.
67.
68.
OBJECTIVE: To evaluate the effect of misoprostol on bone mineral density in postmenopausal women. MATERIALS AND METHODS: The study was performed in a randomized controlled prospective manner in 90 women with menopause at Süleymaniye Maternity and Women's Diseases Teaching and Research Hospital between January and December 2003. Cases were divided into three groups each consisting of 30 women who were in menopause for at least 1 year and had t-scores less than -1 by dual energy X-ray densitometry (DEXA). Group I was treated with misoprostol and calcium, Group II received tibolone and calcium and Group III was given calcium only and considered as control group. In all patients, bone mineral density in L1-L4 vertebrae, femur neck and Ward triangle were measured by DEXA and t and z scores were calculated. RESULTS: All groups were similar demographically. Bone mineral density in L1-L4 vertebrae, femur neck and Ward triangle in the group treated with misoprostol, increased by 5, 8.1 and 3.6%, respectively. In the tibolone group, bone mineral density in L1-L4 vertebrae, femur neck and Ward triangle increased by 8.3, 5.3 and 7.8%, respectively. There was not a significant difference in t and z-scores and bone mineral density measurements between misoprostol and tibolon groups. CONCLUSION: Misoprostol may be an alternative treatment for patients with osteopenia and osteoporosis who are not suitable for hormone replacement therapy.  相似文献   
69.
A rapid, inexpensive, sensitive and specific HPLC-ECD method for the determination of lipoic acid in human plasma was developed and validated over the linearity range of 0.001–10 μg/ml using naproxen sodium as an internal standard (IS). Extraction of lipoic acid and IS from plasma (250 μl) was carried out with a simple one step liquid–liquid extraction using dichloromethane. Similarly solid-phase extraction was carried out using dichloromethane as extraction solvent. The separated organic layer was dried under the stream of nitrogen at 40 °C and the residue was reconstituted with the mobile phase. Complete separation of both lipoic acid and IS at 30 °C on Discovery HS C18 RP column (250 mm × 4.6 mm, 5 μm) was achieved in 6 min using 0.05 M phosphate buffer (pH 2.5 adjusted with phosphoric acid):acetonitrile (50:50, v/v) as a mobile phase pumped at the rate of 1.5 ml/min using electrochemical detector in DC mode at the detector potential of 1.0 V. The limit of detection and limit of quantification of lipoic acid were 200 pg/ml and 1 ng/ml, respectively. While on column limit of detection and limit of quantification of lipoic acid were 10 and 50 pg/ml, respectively. The absolute recoveries of lipoic acid with liquid–liquid and solid-phase extraction were 98.43, 95.65, 101.45, and 97.36, 102.73, 100.17% at 0.5, 1 and 5 μg/ml levels, respectively. Coefficient of variations for both intra-day and inter-day were between 0.28 and 4.97%. The method is validated and will be quite suitable for the analysis of lipoic acid in the plasma of human volunteers as well as patients with diabetes and cardiovascular diseases.  相似文献   
70.
The raw chess whey (CW) treatment capacity of a jet loop membrane bioreactor (JLMBR) was evaluated. Raw CW was first characterized for carbonaceous, nitrogenous and phosphorus compounds. The total COD range of the raw CW was between 73 and 86 kg m−3 and 82% of the total COD was found to be soluble. The JLMBR system, of 32 l capacity was operated continuously for 3 months with a sludge age of 1.1–2.8 days and COD loads of 3.5–33.5 kg-COD m−3 per day. A treatment efficiency of 97% was obtained for 1.6 days of sludge age and COD loads of 22.2 kg-COD m−3 per day. The sludge flocks observed in the system were highly motile, dispersed and had poor settling properties. The membrane filtration characteristics of this sludge were investigated and increasing MLSS concentration decreased membrane flux values.  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