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   1278439篇
  免费   98042篇
  国内免费   1989篇
耳鼻咽喉   18423篇
儿科学   44349篇
妇产科学   35008篇
基础医学   182164篇
口腔科学   33585篇
临床医学   111243篇
内科学   258213篇
皮肤病学   28020篇
神经病学   100360篇
特种医学   51198篇
外国民族医学   660篇
外科学   196376篇
综合类   27048篇
现状与发展   1篇
一般理论   377篇
预防医学   95713篇
眼科学   27912篇
药学   94761篇
  2篇
中国医学   2422篇
肿瘤学   70635篇
  2018年   13133篇
  2017年   9962篇
  2016年   10896篇
  2015年   12369篇
  2014年   17162篇
  2013年   26208篇
  2012年   36018篇
  2011年   38050篇
  2010年   22798篇
  2009年   21806篇
  2008年   36633篇
  2007年   39245篇
  2006年   39499篇
  2005年   38439篇
  2004年   37589篇
  2003年   36444篇
  2002年   35793篇
  2001年   63987篇
  2000年   66494篇
  1999年   56407篇
  1998年   15128篇
  1997年   13754篇
  1996年   14195篇
  1995年   13452篇
  1994年   12765篇
  1993年   11790篇
  1992年   44554篇
  1991年   43466篇
  1990年   42216篇
  1989年   40112篇
  1988年   36894篇
  1987年   36235篇
  1986年   33618篇
  1985年   32278篇
  1984年   24136篇
  1983年   20268篇
  1982年   11723篇
  1981年   10691篇
  1980年   9516篇
  1979年   21341篇
  1978年   14821篇
  1977年   12532篇
  1976年   11693篇
  1975年   12623篇
  1974年   14661篇
  1973年   14117篇
  1972年   12944篇
  1971年   11729篇
  1970年   11050篇
  1969年   10024篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Obesity is a risk factor for renal graft loss. Higher body mass index (BMI) in native kidneys is associated with glomerular hyperfiltration. Whether higher BMI in renal transplants is associated with hyperfiltration is unknown. We investigated the impact of BMI on renal hemodynamics 1 year post-transplant. We analyzed glomerular filtration rate (GFR, (125)I-iothalamate) and effective renal plasma flow (ERPF, (131)I-hippurate) in 838 kidney transplants. Data were analyzed for all patients and for the subpopulation without diabetes. Long-term impact of BMI and renal hemodynamics were explored by Cox-regression. With higher BMI GFR and filtration fraction (FF) increased significantly. Multivariate analysis supported impact of BMI on GFR (adjusted r(2) of the model 0.275) and FF (adjusted r(2) of the model 0.158). This association was not explained by diabetes mellitus. On Cox-regression analysis, lower GFR and higher FF were independent determinants of overall graft loss and graft loss by patient mortality. Lower GFR and higher BMI were determinants of death-censored graft loss, with borderline contribution of higher FF. In renal transplants higher BMI is independently associated with higher GFR and FF one year posttransplant, suggesting glomerular hyperfiltration with altered afferent-efferent balance. Mechanisms underlying the long-term prognostic impact of hyperfiltration deserve further exploration.  相似文献   
972.
Surgery passes through a continuous evolution, thanks to the introduction of new technologies and techniques. Tissue-sparing surgery is a concept introduced in the last years to address prosthetic surgery to a more conservative fashion. We discuss the TSS decalogue with a critical eye, pointing out how traditional surgery is evolving in accordance with TSS statements. Proceedings of the Consensus Conference “TSS in hip and knee replacement”, Rapallo, Italy, 22–24 June 2006  相似文献   
973.
BACKGROUND: The impact of infection with Burkholderia gladioli in cystic fibrosis, other chronic airway diseases and immunosuppressed patients is unknown. METHODS: A six-year retrospective review of all patients with B. gladioli infection was performed in a tertiary referral center with cystic fibrosis and lung transplantation programs. In addition, a targeted survey of all 251 lung transplant recipients was performed. Available B. gladioli isolates were analyzed via pulsed field gel electrophoresis. RESULTS: Thirty-five patients were culture positive for B. gladioli, including 33 CF patients. No bacteremia was identified. Isolates were available in 18 patients and all were genetically distinct. Two-thirds of these isolates were susceptible to usual anti-pseudomonal antibiotics. After acquisition, only 40% of CF patients were chronically infected (> or =2 positive cultures separated by at least 6 months). Chronic infection was associated with resistance to > or =2 antibiotic groups on initial culture and failure of eradication after antibiotic therapy. The impact of acquisition of B. gladioli infection in chronic infection was variable. Three CF patients with chronic infection underwent lung transplantation. One post-transplant patient developed a B. gladioli mediastinal abscess, which was treated successfully. CONCLUSIONS: The majority of patients' culture positive for B. gladioli at our center have CF. B. gladioli infection is often transient and is compatible with satisfactory post-lung transplantation outcomes.  相似文献   
974.
The aqueous extract of the fruits of Terminalia chebula Retz. has been evaluated for its antidiabetic activity in streptozotocin (STZ) induced mild diabetic rats and compared with a known drug, tolbutamide. The oral effective dose (ED) of the extract was observed to be 200 mg/kg body weight, which produced a fall of 55.6% (p<0.01) in the oral glucose tolerance test. Oral administration of ED of aqueous extract of T.chebula (AETC) daily once for two months reduced the elevated blood glucose by 43.2% (p<0.01) and significantly reduced the increase in glycosylated hemoglobin (HbA1c) (p<0.01). The same dose also showed a marked improvement in controlling the elevated blood lipids as well as decreased serum insulin levels in contrast to the untreated diabetic animals. Hepatic and skeletal muscle glycogen content decreased by 75% and 62.9% respectively in diabetic controls, these alterations were partly prevented (34.9% and 21.17%) in AETC treated group when compared to the healthy controls. The in vitro studies with pancreatic islets showed that the insulin release was nearly two times more than that in untreated diabetic animals. The treatment did not have any unfavorable effect on other blood parameters of liver and kidney function tests. LD 50 was found to be above 3 g/kg bw i.e. 15 times of ED, because there were no deaths of animals even at this dose indicating high margin of safety. These findings suggest further investigations for the possible use of the aqueous extract of fruits of T.chebula for the treatment of diabetes.  相似文献   
975.
976.
977.
Arteriovenous (AV) fistulas are common in renal cell carcinoma. These are usually small and asymptomatic. Case reports have previously described symptomatic fistulas in primary renal cell tumour or, less commonly, bone metastases. The current study describes a patient with lung metastases from renal cell carcinoma who developed a symptomatic pulmonary AV fistula. The patient presented with debilitating progressive shortness of breath, which resolved after coiling of the pulmonary AV fistula. Supporting radiographs include a unique ventilation-perfusion finding of perfusion tracer in the kidney that is diagnostic of a pulmonary shunt. This is the first report of a pulmonary fistula from renal cell carcinoma. This rare complication of renal cell carcinoma reflects its diverse clinical presentations and unique tumour biology.  相似文献   
978.
979.
Objective  Stiffness and severe deformity pose a major challenge in total knee arthroplasty. Numerous techniques have been described to gain exposure and improve knee flexion. Tibial tubercle osteotomy provides excellent and safe exposure of the joint, although mechanical and wound complications have been reported. Materials and methods  We present a series of 32 consecutive complex primary total replacements where an osteotomy of the tibial tubercle was utilised. Results  The patients had a mean follow-up of 2 years and 11 months. Following the procedure, with the exception of one case complicated with deep infection, all of the patients had improved clinically. The mean postoperative range of motion had increased to 102° (give P value < 0.005) and there were no cases of delayed union or non-union. A mechanical complication related to technique occurred in one patient; there were no other cases with a postoperative extension lag. Conclusion  In this challenging population group, we have found a tibial tubercle tuberosity osteotomy to greatly facilitate exposure without compromising the clinical and radiographic outcome.  相似文献   
980.
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