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   230篇
  免费   16篇
耳鼻咽喉   40篇
妇产科学   5篇
基础医学   32篇
口腔科学   7篇
临床医学   21篇
内科学   50篇
皮肤病学   1篇
神经病学   7篇
特种医学   3篇
外科学   27篇
预防医学   19篇
药学   16篇
中国医学   1篇
肿瘤学   17篇
  2022年   5篇
  2021年   2篇
  2020年   13篇
  2019年   11篇
  2018年   8篇
  2017年   5篇
  2016年   9篇
  2015年   6篇
  2014年   10篇
  2013年   12篇
  2012年   20篇
  2011年   17篇
  2010年   18篇
  2009年   10篇
  2008年   20篇
  2007年   15篇
  2006年   14篇
  2005年   13篇
  2004年   8篇
  2003年   4篇
  2002年   9篇
  2001年   4篇
  2000年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1986年   1篇
  1984年   1篇
  1974年   2篇
排序方式: 共有246条查询结果,搜索用时 31 毫秒
1.
OBJECTIVE: To evaluate the efficacy of oral moisturizing gel (Oral Balance) in xerostomic patients with primary Sj?gren's syndrome (SS). METHOD AND MATERIALS: Twenty-one xerostomic patients with primary SS were subjected to a single-blind trial in which the efficacy of Oral Balance gel in reducing xerostomia and xerostomia-related oral symptoms was compared with that of a placebo. Both gels were packaged identically and were indiscernible in appearance and taste. Xerostomia was confirmed for all the patients through measurement of stimulated whole saliva. Patients began using the Oral Balance gel three times a day for 90 days, and were then switched to a gel placebo to be used in the same way for the same length of time. Clinical response was evaluated through the patients' subjective assessment (improved, worsened, or unaltered) of both gels. RESULTS: Neither the Oral Balance gel nor the gel placebo affected the salivary output of the patients. The Oral Balance gel presented a substantial statistically significant advantage in the control of burning mouth, mastication, and swallowing. No statistically significant relief of the isolated sensation of oral dryness was established. CONCLUSION: Oral Balance is a useful tool in the management of dryness-related oral symptoms in primary SS, but there is room for enhancing the overall properties of topical preparations designed to reduce oral complaints in xerostomic patients.  相似文献   
2.
The hypothesis that metabolic receptors in skeletal muscle influence heart-rate during exercise was tested by means of a perfused preparation of the rat's hind legs. The isolated leg was connected to the body only by nerve and bone and was perfused with tyrode solution. The humoral changes of exercise were simulated by perfusing with modified tyrode solutions in which concentration of K+, osmolality, concentrations of lactic acid, and inorganic phosphate were changed to reflect to those occurring during heavy exercise. Only perfusion with a solution enriched with lactic acid elicited a significant increase in heart-rate. The response disappeared when the nerve supply to the leg was cooled or sectioned. 20–60 s after the start of perfusion with solution of high [lactic acid] heart-rate began to increase reaching a maximum ( ± SE = 20.2 ± 8.2,n = 7) after about 2 min. The effect on heart-rate increased when the venous concentration of lactic acid was increased the range from 3 to 10 mmol/l. In further experiments, we tried to separate the effects of pH and lactate. Heart-rate responses were induced only at low pH and at low pH the extent to which heart-rate changed increased with increases in lactate concentration.  相似文献   
3.
Summary We have developed a transformation system for Trichoderma hamatum and Trichoderma harzianum Rifai, using dominant markers for selection based on the Escherichia coli hygromycin B phosphotransferase gene (hph) and the -tubulin gene (bml) from Neurospora crassa, respectively. Transformation frequencies and protoplast regeneration were low in both species. All the T. hamatum hygromycin-resistant transformants analysed were mitotically stable, in contrast to those of T. harzianum derived by benomyl resistance, in which only 50% of the transformants analysed were stable. Molecular analysis of transformants showed the integration of the transforming DNA into the genome and indicated that the number and sites of integration varied among the transformants.  相似文献   
4.

Background

Hospital readmissions are an increasingly scrutinized marker of surgical care delivery and quality. There is a paucity of information in the literature regarding the rate, risk factors, and common causes of readmission after surgery for sinonasal cancer.

Methods

We analyzed the Nationwide Readmissions Database for patients who underwent surgery for a diagnosis of sinonasal cancer between 2010 and 2014. Rates, causes, and patient‐, procedure‐, and hospital‐level risk factors for 30‐day readmission were determined. Multivariate logistic regression was used to identify predictors of 30‐day readmission.

Results

Among the 4173 cases, the 30‐day readmission rate was 11.6%, with an average cost per readmission of $18,403. The most common readmission diagnoses were wound complications (15.3%) and infections (13.4%). On multivariate regression, significant risk factors for readmission were chronic renal failure (odds ratio [OR], 2.95; 95% confidence interval [CI], 1.41‐6.17), involvement of the skull base or orbit (OR, 1.67; 95% CI, 1.11‐2.51), nonelective initial surgical admission (OR, 2.35; 95% CI, 1.42‐3.89), and length of stay ≥7 days (OR, 1.87; 95% CI, 1.14‐3.05).

Conclusion

Through the use of a large national database, we found that approximately 1 in 9 patients undergoing surgery for sinonasal cancer was readmitted within 30 days. Readmissions were most commonly associated with wound complications and infections. Factors related to procedural complexity were more important predictors of readmission than patients’ demographics or comorbidities.
  相似文献   
5.
Objectives To profile the clinical presentation and treatment results of esthesioneuroblastomas at the University of California, Los Angeles (UCLA), from 2002 to 2013. Design Retrospective review. Setting Tertiary academic institution. Participants Forty-one patients with esthesioneuroblastomas treated at UCLA. Main Outcome Measures Overall survival (OS) and recurrence-free survival (RFS). Results Thirty-six patients were included with a mean age of 50.1 years and a median duration of follow-up of 33 months. The 5-year RFS and OS were 54% and 82%, respectively. Modified Kadish stage was the only factor identified to affect OS. Multivariate analysis demonstrated that tumor grade was the only factor that had an independent impact on RFS. There was no statistical difference in survival among the surgical approaches chosen. Conclusions The updated data on the UCLA experience reveals that all three surgical approaches chosen provide comparable survival, although longer follow-up will be needed to ascertain if these findings hold true. The endoscopic approach had a statistically significant decrease in length of hospital stay and a trend toward reduced blood loss, intensive care unit admission, and complications. The modified Kadish staging was the only factor identified to predict OS. Multivariate analysis revealed that tumor grade was an independent predictor of recurrence; therefore, its importance should be emphasized in future staging systems.  相似文献   
6.

Background  

Nonalcoholic fatty liver disease is one of the most prevalent forms of chronic liver disease in the Western world. Taurine is a conditionally essential amino acid in humans that may be a promising therapy for treating this disease.  相似文献   
7.
The rat model is widely used in periodontal research and the quality of histological sections is essential. The purpose of this study was to evaluate the histological characteristics of periodontal tissues in Wistar rat maxillae, with different times of fixation and decalcified by nitric acid or formic acid (Anna Morse Solution). Fifteen rats were used. Fixation was performed for 24, 48 and 72 hours. The maxillae were hemi-sectioned and each part was decalcified either in nitric acid for 7 days or in Anna Morse solution for 35 days. Two trained and blinded examiners performed the evaluation. Fourty eight hours of fixation and decalcification with Anna Morse solution showed more clear characteristics of the epithelium-connective tissue interface and of the periodontal structures. Mean measurements between the cementum-enamel junction and the bone crest varied in the different experimental times from 176.5 (+/- 60.45) to 210.94 (+/- 39.33) pixels on the buccal aspect, and from 199.69 (+/- 38.33) to 298.55 (+/-70.81) pixels on the palatal aspect, with no statistically significant differences (ANOVA, p > 0.05). In the same fixation period, decalcification with nitric acid or Anna Morse solution did not display any statistically significant differences. It may be concluded that for a qualitative histological analysis, fixation should preferably be for 48 hours and the demineralization should be made by Anna Morse solution. For a histomorphometric analysis, the decalcification solution does not interfere in the results.  相似文献   
8.
Rat models of hypertension, eg, spontaneously hypertensive stroke-prone rats (SHRSP), display reduced angiotensin-converting enzyme 2 (ACE2) mRNA and protein expression compared with control animals. The aim of this study was to investigate the role of ACE2 in the pathogenesis of hypertension in these models. Therefore, we generated transgenic rats on a SHRSP genetic background expressing the human ACE2 in vascular smooth muscle cells by the use of the SM22 promoter, called SHRSP-ACE2. In these transgenic rats vascular smooth muscle expression of human ACE2 was confirmed by RNase protection, real-time RT-PCR, and ACE2 activity assays. Transgene expression leads to significantly increased circulating levels of angiotensin-(1-7), a prominent product of ACE2. Mean arterial blood pressure was reduced in SHRSP-ACE2 compared to SHRSP rats, and the vasoconstrictive response to intraarterial administration of angiotensin II was attenuated. The latter effect was abolished by previous administration of an ACE2 inhibitor. To evaluate the endothelial function in vivo, endothelium-dependent and endothelium-independent agents such as acetylcholine and sodium nitroprusside, respectively, were applied to the descending thoracic aorta and blood pressure was monitored. Endothelial function turned out to be significantly improved in SHRSP-ACE2 rats compared to SHRSP. These data demonstrate that vascular ACE2 overexpression in SHRSP reduces hypertension probably by locally degrading angiotensin II and improving endothelial function. Thus, activation of the ACE2/angiotensin-(1-7) axis may be a novel therapeutic strategy in hypertension.  相似文献   
9.
10.
Cell suspensions from six Warthin's tumors (WTs) were characterized with fluorescence-labeled cell cytometry. WT lymphocyte subsets were identified with monoclonal antibodies directed against lymphocyte-associated cell antigens including T lymphocyte subsets, B lymphocytes, and natural killer (NK) cells. Results showed that T cell proportions were 58% and B cell proportions were 39%. The T cell helper:cytotoxic-suppressor ratio was 5.7:1 and the B to T cell ratio was 0.8:1. NK cells represented 1.3% of cells. When compared to peripheral blood lymphocytes (PBLs) in the same patients, statistically significant differences were noted between PBLs and WT lymphocytes in the percentage of B lymphocytes (P<.01), T cytotoxic-suppressor lymphocytes (P<.02), NK cells (P<.01), and in the ratios of B to T lymphocytes (P<.01) and T helper to T cytotoxic-suppressor lymphocytes (P<.03). Comparing these data to retrospective data on lymphocyte distribution in normal and reactive lymph nodes, the epithelial component does not appear to exert a local effect on the lymphoid component of WT.  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