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   1528篇
  免费   81篇
  国内免费   13篇
耳鼻咽喉   24篇
儿科学   49篇
妇产科学   26篇
基础医学   231篇
口腔科学   21篇
临床医学   129篇
内科学   429篇
皮肤病学   22篇
神经病学   149篇
特种医学   41篇
外科学   177篇
一般理论   1篇
预防医学   121篇
眼科学   18篇
药学   91篇
中国医学   4篇
肿瘤学   89篇
  2023年   15篇
  2022年   32篇
  2021年   52篇
  2020年   25篇
  2019年   43篇
  2018年   58篇
  2017年   41篇
  2016年   29篇
  2015年   37篇
  2014年   67篇
  2013年   70篇
  2012年   133篇
  2011年   103篇
  2010年   58篇
  2009年   47篇
  2008年   92篇
  2007年   104篇
  2006年   87篇
  2005年   100篇
  2004年   75篇
  2003年   78篇
  2002年   68篇
  2001年   15篇
  2000年   19篇
  1999年   18篇
  1998年   6篇
  1997年   8篇
  1996年   6篇
  1995年   4篇
  1994年   10篇
  1993年   5篇
  1992年   12篇
  1991年   13篇
  1990年   20篇
  1989年   11篇
  1988年   9篇
  1987年   14篇
  1986年   3篇
  1985年   3篇
  1984年   5篇
  1981年   3篇
  1979年   3篇
  1978年   2篇
  1973年   5篇
  1971年   1篇
  1970年   1篇
  1968年   4篇
  1967年   2篇
  1966年   2篇
  1965年   1篇
排序方式: 共有1622条查询结果,搜索用时 13 毫秒
11.
12.
13.
Angiotensin II (AngII) participates in the pathogenesis of kidney damage. Parathyroid hormone (PTH)-related protein (PTHrP), a vasodilator and mitogenic agent, is upregulated during renal injury. The aim of this study was to investigate the potential relation between AngII and PTHrP system in the kidney. Different methods were used to find that both rat mesangial and mouse tubuloepithelial cells express PTHrP and the type 1 PTH/PTHrP receptor (PTH1R). In these cells, AngII increased PTHrP mRNA and protein production. In contrast, PTH1R mRNA was increased in mesangial cells and downregulated in tubular cells, but its protein levels were unmodified in both cells. AT(1) antagonist, but not AT(2), abolished AngII effects on PTHrP/PTH1R. The in vivo effect of AngII was further investigated by systemic infusion (a low dose of 50 ng/kg per min) into normal rats. In controls, PTHrP immunostaining was mainly detected in renal tubules. In AngII-infused rats, PTHrP staining increased in renal tubules and appeared in the glomerulus and the renal vessels. After AngII infusion, PTHR1 staining was markedly increased in all these renal structures at day 3 but remained elevated only in tubules at day 7. The AT(1) antagonist, but not the AT(2), significantly diminished AngII-induced PTHrP and PTHR1 overexpression in the renal tissue, associated with a decrease in tubular damage and fibrosis. The results indicate that AngII regulates renal PTHrP/PTH1R system via AT(1) receptors. These findings demonstrate that PTHrP upregulation occurs in association with the mechanisms of AngII-induced kidney injury.  相似文献   
14.
In middle resource countries (MRCs), cancer control programs are becoming a priority as the pattern of disease shifts from infectious diseases to non-communicable diseases such as breast cancer, the most common cancer among women in MRCs. The Middle Resource Scenarios Working Group of the BHGI 2010 Global Summit met to identify common issues and obstacles to breast cancer detection, diagnosis and treatment in MRCs. They concluded that breast cancer early detection programs continue to be important, should include clinical breast examination (CBE) with or without mammography, and should be coupled with active awareness programs. Mammographic screening is usually opportunistic and early detection programs are often hampered by logistical and financial problems, as well as socio-cultural barriers, despite improved public educational efforts. Although multidisciplinary services for treatment are available, geographical and economic limitations to these services can lead to an inequity in health care access. Without adequate health insurance coverage, limited personal finances can be a significant barrier to care for many patients. Despite the improved availability of services (surgery, pathology, radiology and radiotherapy), quality assurance programs remain a challenge. Better access to anticancer drugs is needed to improve outcomes, as are rehabilitation programs for survivors. Focused and sustained government health care financing in MRCs is needed to improve early detection and treatment of breast cancer.  相似文献   
15.
Hepatolithiasis is defined as the occurrence of stones proximal to the biliary confluence and represents a prevalent disease in South East Asia being uncommon in Western countries. Biliary sepsis, hepatic abscesses and cholangiocarcinoma are considered potential complications. The Authors describe a case of a 68 years male patient affected by a left massive intrahepatic lithiasis secondary to common duct stones and associated to acute pancreatitis. The patient refused surgery and was submitted to a conservative transhepatic percutaneous treatment. After a complete removal of intrahepatic stones and a positioning of external internal biliary drainage (14F), a laparoscopic cholecistectomy was performed. The MRI control showed a complete resolution of the intrahepatic lithiasis. Conservative transhepatic percutaneous approach to hepatolithiasis represents a safe and effective treatment allowing good medium-long term results. Surgery is recommended in case of severe hepatic fibrosis or atrophy, suspected cholangiocarcinoma or multiple strictures with biliary distorsion. Integrated therapeutical protocols in referral multidisciplinary centers-offers the best long term results.  相似文献   
16.
From February 2002 to December 2005, 424 operations for thyroid disease were performed in our institute. Twenty-two patients were suffering from Basedow's disease, 14 female and 8 male, mean age 36 years (range: 23 to 53 years). In each patient the diagnosis of Basedow's disease was made according to common clinical and laboratory criteria, by evaluation of the thyroid hormones, TSH and TRAB. Before operation all patients were rendered euthyroid with antithyroid drug treatment. Fourteen total thyroidectomies (64%) and 8 near-total thyroidectomies (36%) were performed. Postoperative thyroid function status was evaluated before, 3-4 weeks after the operation and then 3, 6,12 and 24 months postoperatively. The patients were classified as euthyroid (FT3-FT4 and TSH normal), hypothyroid (FT3 and/or FT4 reduced and TSH increased), or hyperthyroid (FT3-FT4 increased). In expert hands, surgical treatment appears to be capable of curing the hyperthyroidism of Basedow's disease effectively, with a very low and largely acceptable risk of complications. Among the different types of surgery, total thyroidectomy and near-total thyroidectomy are equally appropriate to ensure there is no risk of recurrence of hyperthyroidism.  相似文献   
17.

Purpose

Estimated glomerular filtration rate (GFR) is a useful tool for the detection of chronic kidney disease (CKD). Several methods have been proposed, but findings can vary in specific groups such as patients with diabetes, elderly and high and low body mass index and, also, with the stage of CKD. The objective of this study was comparing the accuracy of the currently used equations for estimating GFR with that of the gold standard technetium-(99m)-diethylene triamine pentaacetic acid (99mTc-DTPA).

Methods

We performed a cross-sectional study of 129 patients with all five CKD stages. GFR was estimated using the following: 24-h urine creatinine clearance, Cockcroft–Gault equation, MDRD equation, CKD-EPI equation, Hoek’s cystatin C equation, and isotopic 99mTc-DTPA (as gold standard). We evaluated agreement in the whole study population and according to age, sex, weight, and diabetes.

Results

All methods had good agreement. The best agreement was observed with the cystatin C [intraclass coefficient correlation (ICC) 95 % confidence interval (95 % CI), 0.87 (0.82–0.91)], followed by CKD-EPI [ICC 0.83 (0.77–0.88)]. Twenty-four-hour urine creatinine clearance showed the worst agreement in patients older than 65 years [ICC 0.70 (0.56–0.79)]. The Cockcroft–Gault equation showed the worst agreement in younger than 65 years [ICC 0.64 (0.42–0.79)]. The best agreement for classification in the correct CKD stage was with the cystatin C equation [κ = 0.80 (0.74–0.87)]. GFR was overestimated with all methods in CKD stages 4 and 5.

Conclusions

The methods used in clinical practice are adequate for classification of CKD. Cystatin C is the most accurate method, followed by CKD-EPI. The Cockcroft–Gault equation is not accurate in young patients. Twenty-four-hour urine creatinine clearance loses accuracy in patients aged older than 65 years.  相似文献   
18.
Coumarin compounds have been described as anti-inflammatories, and chemotherapeutic agents as well as antioxidants. However, the origin of the antioxidant activity of non phenolic coumarins remains obscure. In the present report, we demonstrate that non-phenolic 7-dialkyl-aminocoumarins may also have significant antioxidant properties against free radicals derived from 2,2′-azobis(2-amidinopropane) dihydrochloride under aerobic conditions. This atypical behaviour is due to the presence of traces of very reactive hydroxycinnamic acid-type compounds. Changing functional groups at the C-3 and C-4 positions shifts the reactivity of the compounds from peroxyl to alkoxyl free radicals. Kinetic and theoretical studies based on Density Functional Theory support the formation of reactive hydroxycinnamic acid and directly link the antioxidant behaviour of the compounds to hydrogen atom transfer.

Relevant antioxidant properties of non-phenolic 7-dialkyl-aminocoumarins against free radicals derived from 2,2′-azobis(2-amidinopropane) dihydrochloride under aerobic conditions have been experimentally and theoretically demonstrated.  相似文献   
19.
An 8-center European clinical trial has established that pirmenol in dosages up to 400 mg daily is effective and safe for treating stable, high frequency, ventricular ectopy. At dosages of 300 mg and 400 mg of pirmenol a day, the average frequency of ectopy/hour decreased markedly compared with baseline values. The percentage of responders (premature ventricular contraction suppression of 70% compared with baseline) among the patients receiving 300 mg or 400 mg of pirmenol/day was significantly higher than in the placebo group. Observation of the frequency of reported adverse experiences, clinical laboratory tests and electrocardiographic tracings shows that dosages of pirmenol up to 400 mg daily were well tolerated.  相似文献   
20.
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