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   277篇
  免费   36篇
  国内免费   3篇
耳鼻咽喉   2篇
儿科学   2篇
基础医学   69篇
口腔科学   4篇
临床医学   13篇
内科学   45篇
皮肤病学   1篇
神经病学   40篇
特种医学   6篇
外科学   32篇
预防医学   21篇
药学   41篇
中国医学   28篇
肿瘤学   12篇
  2023年   2篇
  2022年   3篇
  2021年   4篇
  2020年   5篇
  2019年   2篇
  2018年   1篇
  2017年   6篇
  2016年   2篇
  2015年   5篇
  2014年   16篇
  2013年   13篇
  2012年   21篇
  2011年   27篇
  2010年   15篇
  2009年   10篇
  2008年   8篇
  2007年   20篇
  2006年   18篇
  2005年   11篇
  2004年   14篇
  2003年   13篇
  2002年   4篇
  2001年   14篇
  2000年   10篇
  1999年   12篇
  1998年   3篇
  1997年   3篇
  1996年   4篇
  1995年   4篇
  1994年   1篇
  1993年   1篇
  1992年   8篇
  1991年   8篇
  1990年   9篇
  1989年   7篇
  1988年   4篇
  1985年   1篇
  1983年   1篇
  1978年   1篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
排序方式: 共有316条查询结果,搜索用时 31 毫秒
1.
The matching of the aesthetic, functional, and psychosocial results of a facial deformity may produce devastating effects in its carriers, especially if the lesion is extensive or the treatment is aggressive. Because of this, the objective of the present article was to evaluate patient's satisfaction rating after surgical facial reconstruction or rehabilitation with oral and maxillofacial prosthesis, by means of reviewing the literature.  相似文献   
2.

Purpose

Portable polysomnography (PSG) and cardiorespiratory polygraphy are increasingly being used in the assessment of sleep-disordered breathing (SDB) in heart failure patients. Scoring of SDB from cardiorespiratory polygraphy recordings is based only on respiratory signals, while electroencephalographic, electrooculographic and electromyographic channels are taken into account when using PSG recordings. The aim of this study was to assess the agreement between these two scoring methods.

Methods

An overnight sleep study was performed in 67 heart failure patients using a standard portable polysomnograph. Each recording was scored twice, once using all acquired signals (PSG mode) and, after a median of 64 days, using only respiratory signals (cardiorespiratory mode). Agreement was assessed by Bland–Altman analysis and Cohen’s kappa.

Results

We found that (1) more respiratory events were detected using cardiorespiratory analysis [median (25th percentile, 75th percentile), 75 (39, 200) events] compared to analysis of portable PSG [69 (29, 173) events, p?<?0.0001], the extra events being, for the vast majority, central in origin; (2) the apnea/hypopnea index (AHI) estimated by cardiorespiratory polygraphy [11.9 (5.7, 30.8)/h] showed a negligible negative bias relative to portable PSG [15.1 (5.7, 33.6)/h; bias, ?0.8 (?2.9, 0.4)/h, p?=?0.0002]; (3) limits of agreement between the two systems (?6.2/h, 1.7/h) were much smaller than those previously observed between two nights using the same scoring modality; and (4) the kappa coefficient using categorised AHI was 0.89 (95 % confidence interval (CI) 0.82, 0.96).

Conclusions

We found a high degree of agreement between the AHIs obtained from the two scoring methods, thus suggesting that cardiorespiratory polygraphy may be used as an alternative to portable PSG in the assessment of SDB in heart failure patients.
  相似文献   
3.
4.
Sleep and Breathing - Narcolepsy is a disabling, rare, and chronic sleep disorder, currently classified as distinct central nervous system hypersomnia in narcolepsy type 1 (NT1) and narcolepsy type...  相似文献   
5.
A nontoxic mutant (LTK7) of the Escherichia coli heat-labile enterotoxin (LT) lacking ADP-ribosylating activity but retaining holotoxin formation was constructed. By using site-directed mutagenesis, the arginine at position 7 of the A subunit was replaced with lysine. This molecule, which was nontoxic in several assays, was able to bind to eukaryotic cells and acted as a mucosal adjuvant for co-administered proteins; BALB/c mice immunized intranasally with LTK7 and ovalbumin developed high levels of serum and local antibodies to ovalbumin and toxin. In addition, mice immunized intranasally with fragment C of tetanus toxin and LTK7 were protected against lethal challenge with tetanus toxin. Thus nontoxic mutants of heat-labile toxin can act as effective intranasal mucosal adjuvants.  相似文献   
6.

Purpose

In Parkinson’s disease (PD) patients, REM sleep behavior disorder (RBD) might precede PD or develop with or after the onset of PD. No previous study has explored differences between these two groups. The aim of this study was therefore to compare clinical features and REM sleep chin electromyographic patterns between patients in whom RBD heralded PD and those in whom RBD occurrence coincided with or followed the clinical manifestations of PD.

Method

Twenty-seven consecutive PD patients (mean age 67.9 years) were enrolled. Detailed clinical, laboratory, and polysomnographic studies were obtained in all participants.

Results

Sixteen of the 27 patients were affected by RBD. These had a significantly higher stage of PD and took significantly higher doses of dopaminergic therapy; their disease duration tended to be longer, and their cognitive status tended to be lower. PD patients in whom RBD preceded PD (n?=?6) did not differ from PD patients without RBD in disease parameters, while PD patients in whom RBD developed with or after PD (n?=?10) showed a significantly higher disease stage, took significantly higher dopaminergic therapy, and had a longer disease duration.

Conclusion

Our findings are compatible with the hypothesis that patients in whom RBD precedes, or does not precede, PD might constitute two possibly distinct clinical and physiopathological groups, based on different progressive neuropathological sequences of events.  相似文献   
7.
8.
Neisseria meningitidis is an obligate human commensal that commonly colonizes the oropharyngeal mucosa. Carriage is age dependent and very common in young adults. The relationships between carriage and invasive disease are not completely understood. In this work, we performed a longitudinal carrier study in adolescents and young adults (173 subjects). Overall, 32 subjects (18.5%) had results that were positive for meningococcal carriage in at least one visit (average monthly carriage rate, 12.1%). Only five subjects tested positive at all four visits. All meningococcal isolates were characterized by molecular and serological techniques. Multilocus sequence typing, PorA typing, and sequencing of the 4CMenB vaccine antigens were used to assess strain diversity. The majority of positive subjects were colonized by capsule null (34.4%) and capsular group B strains (28.1%), accounting for 23.5% and 29.4% of the total number of isolates, respectively. The fHbp and nhba genes were present in all isolates, while the nadA gene was present in 5% of the isolates. The genetic variability of the 4CMenB vaccine antigens in this collection was relatively high compared with that of other disease-causing strain panels. Indications about the persistence of the carriage state were limited to the time span of the study. All strains isolated from the same subject were identical or cumulated minor changes over time. The expression levels and antigenicities of the 4CMenB vaccine antigens in each strain were analyzed by the meningococcal antigen typing system (MATS), which revealed that expression can change over time in the same individual. Future analysis of antigen variability and expression in carrier strains after the introduction of the MenB vaccine will allow for a definition of its impact on nasopharyngeal/oropharyngeal carriage.  相似文献   
9.
In this retrospective study, we evaluated 53 patients diagnosed with Burkitt's lymphoma (BL). Patients were admitted to the Pediatric Department of Santa Casa de S?o Paulo, Brazil from August 1988 to September 2006. The male gender was found more frequently in the proportion of three males to one female. At the time of the diagnosis, the mean age was 6 years. The most frequent clinical presentation was abdominal (extra nodal) in 42 (79.2%) cases. The patients were treated with chemotherapy using two different treatment methods, 30 cases until September 1994 with BGLTI -87 and the other 23 until September of 2006 with BGLTI -96. According to Murphy's classification, 90.2% of the patients were diagnosed as stages III and VI showing an advanced disease at time of diagnosis. Using Tissue Microarrays (TMA); we searched for the expression of the Epstein-Barr virus (EBV) RNA in 50 patients. The presence of EBV using in situ hybridization was found in 33/50 (66%) and there was no association between the presence of the virus in the tumor cells or patient age, as well as the survival rate. There was 74.5% global survival rate until September, 2005 of 12 years and 8 months. The disease free survival rate was 86.5%. The frequency of the EBV association with this neoplasia in Brazil is intermediate between the endemic and sporadic forms of disease.  相似文献   
10.
The toxicity of pertussis toxin is mediated by the ADP-ribosyltransferase activity of subunit S1. To understand the structure-function relationship of subunit S1 and guide the construction of nontoxic molecules suitable for vaccines, we constructed and expressed in Escherichia coli a series of amino-terminal and carboxyl-terminal deletion mutants as well as a number of molecules containing amino acid substitutions. The shortest peptide still retaining enzymatic activity contains amino acids 2-179. Within this region we identified three mutants in which amino acid substitutions abolish the enzymatic activity. Mutation of amino acids 8 and 9 or 50 and 53, located within the region of the S1 subunit of pertussis toxin homologous to cholera toxin, causes loss of enzymatic activity. Outside this homology region, substitution of Glu-129 with glycine or aspartic acid also eliminates the enzymatic activity of the S1 subunit. In this respect, Glu-129 resembles the glutamic acid that is crucial for the catalytic activity of diphtheria and Pseudomonas toxins. Once introduced into the Bordetella pertussis chromosome, the above mutations should lead to the synthesis of nontoxic pertussis toxin molecules suitable for vaccine production.  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