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   1859篇
  免费   83篇
  国内免费   11篇
耳鼻咽喉   18篇
儿科学   44篇
妇产科学   20篇
基础医学   135篇
口腔科学   62篇
临床医学   181篇
内科学   509篇
皮肤病学   22篇
神经病学   104篇
特种医学   55篇
外科学   398篇
综合类   22篇
一般理论   2篇
预防医学   49篇
眼科学   70篇
药学   145篇
中国医学   10篇
肿瘤学   107篇
  2024年   2篇
  2023年   16篇
  2022年   54篇
  2021年   111篇
  2020年   65篇
  2019年   67篇
  2018年   62篇
  2017年   56篇
  2016年   57篇
  2015年   73篇
  2014年   115篇
  2013年   140篇
  2012年   197篇
  2011年   201篇
  2010年   109篇
  2009年   97篇
  2008年   111篇
  2007年   106篇
  2006年   106篇
  2005年   70篇
  2004年   59篇
  2003年   40篇
  2002年   23篇
  2001年   1篇
  2000年   1篇
  1999年   4篇
  1998年   1篇
  1997年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1988年   1篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1966年   1篇
排序方式: 共有1953条查询结果,搜索用时 15 毫秒
11.
12.
OBJECTIVES: The primary aim of this study is to determine if patients with end-stage renal disease (ESRD) on peritoneal dialysis (PD) have a higher risk of developing acute pancreatitis (AP) than patients on hemodialysis (HD). The secondary aim is to compare the outcomes of AP between the two groups. METHOD: This is a retrospective case-control study. The study groups consisted of all patients initiated on HD and PD between January 1, 1998 and August 1, 2003. AP was identified using ICD-9 codes. Statistical analysis was carried out using Poisson regression, Kaplan-Meier curve, log-rank test, and Cox regression. RESULTS: One thousand two hundred and thirty-three and 160 eligible patients were identified in the HD and PD groups, respectively. Twenty-eight patients had AP. Eight patients were excluded as they had identifiable etiologies for AP. Of the remaining 20 patients with AP, 14 were in the HD group and 6 were in the PD group (p= 0.009). Incidence of AP was 18.4 per 1,000 person-years in the PD group and 6.5 per 1,000 person-years in the HD group (p= 0.033). Kaplan-Meier curves showed a significant difference in AP-free survival between the two groups (log-rank p= 0.026). Using time-dependent analysis, the hazard ratio for AP in PD patients after adjustment for age and sex was 3.94 (p= 0.006). There was no observed difference in length of hospital stay and ICU stay. All cases of AP were interstitial. There were no complications or deaths related to AP. CONCLUSION: PD is a risk factor for AP. There is no statistical difference in AP-related mortality and morbidity between HD and PD.  相似文献   
13.
Percutaneous transcatheter interventions for valve replacement or implantation is one of the most exciting developments in the field of interventional cardiology. Valvular stenosis has been treated by balloon dilatation with early and late results; however, treatment for valvular regurgitation has remained surgical until now. Most new designs have been investigated for implantation of valves in the left or right ventricular outflow tracts. Patients with surgery on the right ventricular outflow tract for congenital heart disease constitute the most common group for reoperations during late follow-up. Surgical pulmonary valve replacement can be performed with low mortality; however, it sets up a substrate for future operations. Also, the risk of cardiopulmonary bypass, infection, bleeding, and ventricular dysfunction remains. A transcatheter technique is likely to have more acceptance and may expand the indications for early intervention for right ventricular outflow tract dysfunction.  相似文献   
14.
Oral submucous fibrosis (OSMF) is a potentially malignant disorder of the oral cavity. Most of the people affected by OSMF are betel quid chewers. It is characterized by epithelial atrophy and progressive accumulation of collagen fibers in lamina propria and submucosa of the oral mucosa. 7.6% of OSMF cases undergo oral squamous cell carcinoma (OSCC) transformation of which majority display low grade of tumor differentiation. In the present paper, a hypothesis has been proposed to correlate atrophy, turnover rate and surface keratization in OSMF with degree of tumor differentiation in OSCC. A novel hypothesis for epithelial atrophy in OSMF has also been emphasized.  相似文献   
15.
Objectives:To assess the null hypothesis that there is no difference in the rate of dental development and the occurrence of selected developmental anomalies related to shape, number, structure, and position of teeth between subjects with impacted mandibular canines and those with normally erupted canines.Materials and Methods:Pretreatment records of 42 subjects diagnosed with mandibular canines impaction (impaction group: IG) were compared with those of 84 subjects serving as a control reference sample (control group: CG). Independent t-tests were used to compare mean dental ages between the groups. Intergroup differences in distribution of subjects based on the rate of dental development and occurrence of selected dental anomalies were assessed using χ2 tests. Odds of late, normal, and early developers and various categories of developmental anomalies between the IG and the CG were evaluated in terms of odds ratios.Results:Mean dental age for the IG was lower than that for the CG in general. Specifically, this was true for girls (P < .05). Differences in the distribution of the subjects based on the rate of dental development and occurrence of positional anomalies also reached statistical significance (P < .05). The IG showed a higher frequency of late developers and positional anomalies compared with controls (odds ratios 3.00 and 2.82, respectively; P < .05).Conclusions:The null hypothesis was rejected. We identified close association of female subjects in the IG with retarded dental development compared with the female orthodontic patients. Increased frequency of positional developmental anomalies was also remarkable in the IG.  相似文献   
16.

Aims and Objective

To evaluate the prevalence, clinical features, diagnostic laboratory values and treatment outcome of giant cell lesions (brown tumors) associated with primary hyperparathyroidism (PHPT) in oral and maxillofacial region.

Study Design

A 5 year retrospective data was analyzed wherein all histopathologically proven cases of giant cell lesions involving oral and maxillofacial region were evaluated. Out of these cases, those associated with PHPT were tabulated. Correlation was established with other concomitant clinical features and also with the laboratory values of altered serum calcium, phosphate, alkaline phosphate and parathormone. Follow up of these cases after the correction of PHPT was also noted.

Result

Out of 85 cases of histopathologically proven giant cell lesions, five cases were associated with PHPT. There was involvement of maxilla and mandible in one case each. Only frontal bone was involved in two cases. Fifth case had multiple lytic lesions in maxilla and frontal bone. All patients consistently showed very high values of alkaline phosphate and parathormone. Hypercalcemia and hypophosphatemia was noted in four cases. All cases showed regression of the lytic lesion after parathyroidectomy obviating the need for surgical excision of the jaw lesions.

Conclusion

Giant cell lesions (brown tumors) associated with PHPT in oral and maxillofacial region are rare clinical entities. The prevalence of PHPT associated giant cell lesions is 5.9 %. They are clinically, radiologically and histopathologically similar to any other peripheral or central giant cell tumor. Relevant history may alert the clinician and altered biochemical values may help in correlating the oral and maxillofacial findings with the underlying systemic disease. At times, the brown tumor maybe the only presenting sign leading to the diagnosis of PHPT.  相似文献   
17.
The authors report a 14-d-old neonate who presented with lethargy, polyuria and dehydration and was found to have severe hypercalcemia with hyperparathyroidism. This neonate was treated with saline hydration, diuresis and injection pamidronate. Genetic analysis revealed a compound heterozygous mutation of CaSR.  相似文献   
18.
We report the design‐synthesis of several nitrothiophene containing molecules as antituberculosis agents. The molecules were designed on the basis of previously reported nitrofuran molecules in our laboratory, and the α,β‐unsaturated linker was modified to cyclized linker in order to overcome the challenge of low solubility and possible toxicity. The stereo‐electronic properties such as HOMO, LUMO, and HOMO‐LUMO gap along with other properties such as aqueous solvation energies and QPLogS values were studied. The designed molecules were synthesized and tested for in vitro antituberculosis activity, and some molecules were found to be highly active comparable to standard drugs. Further, the aqueous solubility was determined using visual inspection method and the designed molecules were found to be more soluble than their chalcone counterparts. Cytotoxicity studies were performed and the molecules were found to be non‐cytotoxic. Electroanalytical studies proved nitro reduction as the mechanism of action for these molecules. Thus, this study provides potential nitrothiophene containing hits with improved solubility and reduced chances of toxicity.  相似文献   
19.
20.
Reply     
  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