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   111篇
  免费   2篇
  国内免费   1篇
儿科学   22篇
妇产科学   5篇
基础医学   17篇
口腔科学   3篇
临床医学   12篇
内科学   29篇
皮肤病学   2篇
神经病学   3篇
外科学   2篇
综合类   4篇
预防医学   7篇
药学   2篇
肿瘤学   6篇
  2023年   2篇
  2022年   6篇
  2021年   5篇
  2020年   4篇
  2019年   1篇
  2018年   5篇
  2017年   2篇
  2016年   2篇
  2015年   7篇
  2014年   7篇
  2013年   6篇
  2012年   10篇
  2011年   14篇
  2010年   6篇
  2009年   5篇
  2008年   5篇
  2007年   6篇
  2006年   5篇
  2005年   8篇
  2004年   3篇
  2003年   1篇
  2001年   1篇
  1999年   2篇
  1998年   1篇
排序方式: 共有114条查询结果,搜索用时 15 毫秒
1.
Purpose: Our purpose was to assess the effect of chromosomal mosaicism in cleavage-stage human embryos on the accuracy of single-cell analysis for preimplantation genetic diagnosis. Methods: Multicolor fluorescence in situ hybridization with X, Y, and 7 or X, Y, 7, and 18 chromosome-specific probes was used to detect aneuploidy in cleavage-stage human embryos. Results: Most nuclei were diploid for the chromosomes tested but there was extensive mosaicism including monosomic, double-monosomic, nullisomic, chaotic, and haploid nuclei. Conclusions: Identification of sex by analysis of a single cleavage-stage nucleus is accurate but 7% of females are not identified. One or both parental chromosomes 7 were absent in at least 6.5% of the nuclei. With autosomal recessive conditions such as cystic fibrosis, carriers would be misdiagnosed as normal or affected. With autosomal dominant conditions, failure to analyze the affected parents allele (1.6–2.5%) would cause a serious misdiagnosis and analysis of at least two nuclei is necessary to reduce errors.  相似文献   
2.
3.
4.
Interleukin 4 (IL-4) stimulates and amplifies the inflammatory response, stimulates collagen synthesis in fibroblasts, promotes the progression to fibrosis and has been shown to inhibit the production of several inflammatory cytokines in the development of bronchopulmonary dysplasia (BPD) and airway hyperreactivity. We aimed to investigate whether IL-4 polymorphisms in ventilated preterm infants were associated with BPD. BPD was defined as infants who remained dependent on active respiratory support or oxygen supplementation at 36 weeks postconceptional age. A case-control study of 224 preterm infants (<30 weeks) who had respiratory distress syndrome and needed intermittent mandatory ventilation (IMV) were undertaken between January 1999 and December 2003. The typing of each genetic polymorphism was performed by polymerase-chain-reaction-based restriction analysis. Genotype distribution and allelic frequencies were compared between ventilated preterm infants who developed BPD and those who did not and the duration of IMV. The demography of these ventilated BPD and non-BPD preterm infants was not different. We observed no significant differences in genotype distribution or allelic frequency of the IL-4 intron 3 or IL-4 promoter polymorphisms between ventilated preterm infants who developed BPD and who did not. There was no significant association of the genotype or allelic frequency of IL-4 polymorphism with duration of IMV. We conclude that neither IL-4 intron 3 nor the 590 promoter polymorphism is a useful marker for predicting the susceptibility to BPD in ventilated Taiwanese preterm infants.  相似文献   
5.
6.
7.
Bupivacaine lipospheres were prepared as a parenteral sustained-release system for post-operative pain management. Bupivacaine free base was incorporated into micron-sized triglyceride solid particles coated with phospholipids, which were formed via a hot emulsification and cold resolidification process. The bupivacaine liposphere dispersions were characterized with respect to drug loading, particle-size distribution, and morphology. Gelation of the fluid liposphere dispersions was observed at different time intervals upon storage. The type of phospholipids used in the formulation was found to have a major impact on the gelation of the dispersion. The use of synthetic phospholipids instead of the natural phospholipids in the formulation yielded bupivacaine liposphere dispersions exhibiting prolonged gelation time. The addition of a hydrophilic cellulosic polymer can further improve the physical stability of the dispersion.  相似文献   
8.
Cellular immune selection with hepatitis C virus persistence in humans   总被引:16,自引:0,他引:16  
Hepatitis C virus (HCV) infection frequently persists despite substantial virus-specific cellular immune responses. To determine if immunologically driven sequence variation occurs with HCV persistence, we coordinately analyzed sequence evolution and CD8+ T cell responses to epitopes covering the entire HCV polyprotein in subjects who were followed prospectively from before infection to beyond the first year. There were no substitutions in T cell epitopes for a year after infection in a subject who cleared viremia. In contrast, in subjects with persistent viremia and detectable T cell responses, we observed substitutions in 69% of T cell epitopes, and every subject had a substitution in at least one epitope. In addition, amino acid substitutions occurred 13-fold more often within than outside T cell epitopes (P < 0.001, range 5-38). T lymphocyte recognition of 8 of 10 mutant peptides was markedly reduced compared with the initial sequence, indicating viral escape. Of 16 nonenvelope substitutions that occurred outside of known T cell epitopes, 8 represented conversion to consensus (P = 0.015). These findings reveal two distinct mechanisms of sequence evolution involved in HCV persistence: viral escape from CD8+ T cell responses and optimization of replicative capacity.  相似文献   
9.
BACKGROUND AND PURPOSE: Persistence of neutrophils in the tracheal fluid of premature infants is associated with chronic lung disease (CLD). Interleukin-8 (IL-8) is a potent neutrophil chemoattractant. This study investigated whether IL-8 is increased in the bronchoalveolar lavage fluid of premature infants with different types of CLD. METHODS: Forty two very low birth weight infants who required mechanical ventilation were recruited. Twenty eight of these infants developed CLD and 14 infants recovered without developing CLD. Four additional infants receiving mechanical ventilation for non-respiratory reasons were also enrolled as controls. CLD was defined as requirement for supplemental oxygen at 28 days of age and chest radiograph showing characteristic appearance. CLD was further classified into 3 subtypes: bronchopulmonary dysplasia (BPD), Wilson-Mikity syndrome (WMS) and chronic pulmonary insufficiency of prematurity (CPIP). RESULTS: IL-8 in bronchoalveolar lavage fluid was significantly increased in the CLD group by 8 days of age compared to those who did not develop CLD (p < 0.05). For infants without CLD, IL-8 increased from 963 pg/mL on day 1 after delivery to 1463 pg/mL on day 4, and decreased to 1,000 pg/mL on day 8. For infants with BPD, IL-8 increased from 925 pg/mL on day 1 after delivery to 2,650 pg/mL on day 8, and then gradually decreased to 1,500 pg/mL on day 28. Infants with WMS had significantly higher IL-8 from the first day after delivery (4,567 pg/mL) than infants with BPD or CPIP and this difference persisted to age 28 days (2475 pg/mL). CONCLUSIONS: Persistent inflammation could be a major contributory factor in the development of CLD. The different patterns of response to inflammation in different types of CLD may have implications for the design of appropriate strategies to prevent and treat CLD.  相似文献   
10.
Carcinoma of unknown primary origin (CUP) is characterized by diverse histological subtypes and clinical presentations, ranging from clinically indolent to frankly aggressive behaviors. This study aimed to identify prognostic factors of CUP and to develop a simple risk model to predict survival in a cohort of Asian patients.We retrospectively reviewed 190 patients diagnosed with CUP between 2007 and 2012 at a single medical center in Taiwan. The clinicopathological parameters and outcomes of our cohort were analyzed. A risk model was developed using multivariate logistic regression and a prognostic score was generated.The prognostic score was calculated based on 3 independent prognostic variables: the Eastern Cooperative Oncology Group (ECOG) scale (0 points if the score was 1, 2 points if it was 2–4), visceral organ involvement (0 points if no involvement, 1 point if involved), and the neutrophil-to-lymphocyte ratio (0 points if ≤3, 1 point if >3). Patients were stratified into good (score 0), intermediate (score 1–2), and poor (score 3–4) prognostic groups based on the risk model. The median survival (95% confidence interval) was 1086 days (500–1617, n = 42), 305 days (237–372, n = 75), and 64 days (44–84, n = 73) for the good, intermediate, and poor prognostic groups, respectively. The c-statistics using the risk model and ECOG scale for the outcome of 1-year mortality were 0.80 and 0.70 (P = 0.038), respectively.In this study, we developed a simple risk model that accurately predicted survival in patients with CUP. This scoring system may be used to help patients and clinicians determine appropriate treatments.  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