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   2378篇
  免费   81篇
  国内免费   9篇
耳鼻咽喉   16篇
儿科学   53篇
妇产科学   12篇
基础医学   279篇
口腔科学   8篇
临床医学   119篇
内科学   545篇
皮肤病学   7篇
神经病学   254篇
特种医学   49篇
外科学   595篇
综合类   12篇
预防医学   44篇
眼科学   127篇
药学   152篇
中国医学   3篇
肿瘤学   193篇
  2022年   11篇
  2021年   24篇
  2020年   15篇
  2019年   18篇
  2018年   29篇
  2017年   23篇
  2016年   30篇
  2015年   34篇
  2014年   46篇
  2013年   71篇
  2012年   101篇
  2011年   118篇
  2010年   69篇
  2009年   59篇
  2008年   119篇
  2007年   153篇
  2006年   156篇
  2005年   147篇
  2004年   163篇
  2003年   158篇
  2002年   177篇
  2001年   34篇
  2000年   67篇
  1999年   46篇
  1998年   54篇
  1997年   57篇
  1996年   53篇
  1995年   40篇
  1994年   38篇
  1993年   30篇
  1992年   32篇
  1991年   28篇
  1990年   32篇
  1989年   31篇
  1988年   39篇
  1987年   14篇
  1986年   16篇
  1985年   16篇
  1984年   15篇
  1983年   12篇
  1982年   9篇
  1981年   12篇
  1980年   5篇
  1979年   10篇
  1978年   7篇
  1977年   7篇
  1976年   6篇
  1972年   4篇
  1970年   6篇
  1968年   4篇
排序方式: 共有2468条查询结果,搜索用时 15 毫秒
41.
42.
43.
Conventional hemorrhoidectomy is applied for the treatment of prolapsing internal hemorrhoids. Recently, less-invasive treatments such as sclerotherapy using aluminum potassium sulphate/tannic acid (ALTA) and a procedure for prolapse and hemorrhoids (PPH) have been introduced. We compared the results of sclerotherapy with ALTA and an improved type of PPH03 with those of hemorrhoidectomy. Between January 2006 and March 2009, we performed hemorrhoidectomy in 464 patients, ALTA in 940 patients, and PPH in 148 patients with second- and third-degree internal hemorrhoids according to the Goligher''s classification. The volume of ALTA injected into a hemorrhoid was 7.3 ± 2.2 (mean ± SD) mL. The duration of the operation was significantly shorter in ALTA (13 ± 2 minutes) than in hemorrhoidectomy (43 ± 5 minutes) or PPH (32 ± 12 minutes). Postoperative pain, requiring intravenous pain medications, occurred in 65 cases (14%) in hemorrhoidectomy, in 16 cases (1.7%) in ALTA, and in 1 case (0.7%) in PPH. The disappearance rates of prolapse were 100% in hemorrhoidectomy, 96% in ALTA, and 98.6% in PPH. ALTA can be performed on an outpatient basis without any severe pain or complication, and PPH is a useful alternative treatment with less pain. Less-invasive treatments are beneficial when performed with care to avoid complications.  相似文献   
44.
45.

Background

Pancreatic cancer is an aggressive malignancy with one of the worst mortality rates of all cancers. Recently, collapsin response mediator proteins (CRMPs) were reported to be associated with proliferation, apoptosis, differentiation, and invasion in several cancers. However, CRMP expression and their role in pancreatic cancer have not been investigated. This study aimed to clarify the clinical significance of CRMPs in pancreatic cancer.

Methods

Expression of crmp genes in 11 pairs of pancreatic cancer and corresponding noncancerous pancreas tissues were examined by real-time RT-PCR. Knockdown of CRMP4 expression using siRNA was examined in pancreatic cancer cell lines to determine whether CRMP4 regulates cell proliferation and invasion in vitro. Furthermore, CRMP4 protein levels in primary tumors of pancreatic cancer (n = 53) were examined by immunohistochemistry and compared with the clinicopathological features of the tumors.

Results

Of all the CRMPs, only CRMP4 was differentially expressed in pancreatic cancer tissues (p = 0.008). CRMP4 knockdown using siRNA reduced cellular invasion, but did not affect proliferation. The expression of CRMP4 was detected immunohistochemically in 34 (64.2 %) of the 53 pancreatic cancer samples, and CRMP4 expression was correlated with severe venous invasion (p = 0.044), stage (p = 0.019), and liver metastasis (p = 0.021). Multivariate analyses suggested that venous invasion and CRMP4 overexpression were prognostic factors for survival.

Conclusions

Our results suggested that CRMP4 is significantly associated with poor prognosis by promoting liver metastasis and can serve as a novel therapeutic target for pancreatic cancer.
  相似文献   
46.
47.
48.

Purpose

We assessed the incidence of coronary artery disease (CAD) during hospitalization after emergency surgery for a type A acute aortic dissection.

Methods

A total of 123 patients underwent multi-slice computed tomography (MSCT) scans during an early stage after surgery. The patients were divided into two groups: group I consisted of 14 patients (11.4 %) who had coronary artery stenosis of more than 75 % on MSCT, and group II consisted of 109 patients (88.6 %) who had no coronary lesions.

Results

The prevalence of diabetes, dyslipidemia and a smoking history was significantly higher in group I. Although the serum low-density lipoprotein cholesterol levels were similar, the high-density lipoprotein cholesterol (HDL) level was significantly lower in group I (36.4 ± 7.9 mg/dl) than in group II (49.6 ± 13.5 mg/dl, P = 0.0005). The maximum carotid intima-media thickness (IMT) was significantly thicker in group I (1.17 ± 0.37 mm) compared to group II (0.96 ± 0.33 mm, P = 0.0297). The logistic regression analysis detected that a carotid IMT over 1.1 mm (odds ratio 4.35, P = 0.0371) and HDL less than 40 mg/dl (odds ratio 3.90, P = 0.0482) were predictors for CAD.

Conclusions

CAD screening should be recommended for patients with aortic dissection who have several atherosclerosis risk factors, even after emergency surgery.  相似文献   
49.
Osteodystrophy in patients with chronic hepatitis and liver cirrhosis   总被引:1,自引:0,他引:1  
Bone mineral density (BMD) of the lumber vertebrae and factors related to bone metabolism were determined in patients with chronic viral hepatitis and patients with liver cirrhosis to clarify correlations between hepatic dysfunction, considered to be one of the causes of hepatic osteodystrophy, and decrease in bone mass. BMD of the second to fourth lumbar vertebrae was determined with a Lunar (Madison, WI, USA) DPX, a dual-energy X-ray absorptiometry diagnostic system. BMD was significantly lowest in patients with liver cirrhosis, followed by patients with chronic hepatitis, and healthy subjects, in this order. There was a significantly positive but weak correlation between albumin and BMD. Levels of 25(OH)D and 1,25(OH)2D were significantly lower in patients with liver cirrhosis than in those with chronic hepatitis. BMD and vitamin D were decreased in all patients whose cholinesterase (ChE) was below 0.3ΔpH. Urinary pyridinoline(Upyr) was significantly higher in the patients with liver cirrhosis, in whom bone mass was decreased, than in the patients with chronic hepatitis, whereas serum osteocalcin levels were distributed in the upper normal range in patients with chronic hepatitis and those with liver cirrhosis. There was a positive correlation between 25(OH)D and serum osteocalcin levels in patients with liver cirrhosis. These results indicate that osteogenesis is decreased and suggest that the decrease in BMD which occurs in viral liver cirrhosis, probably related to decreased, bone formation and slight promotion of bone resorption, reflects deranged hepatic function. This is the first report of Upyr and urinary deoxypyridinoline (UDpyr) determination in patients with liver cirrhosis and patients with chronic hepatitis. The negative correlation of Upyr and UDpyr with ChE is a novel finding.  相似文献   
50.
Autoimmunity causes pathological conditions resulting in autoimmune diseases (ADs). Although autoimmunity is a mystery, immunological dogma suggests that autoreactive cell reactivation (ACR) breaks self-tolerance and induces autoimmunity. Thus, ACR is a royal pathway for ADs. Cumulative evidence implicates environmental factors as secondary triggers of ADs in the genetically susceptible hosts. Infection is the most likely trigger. Although several mechanisms have been proposed to explain how infectious agents trigger ADs, ACR is assumed to be an essential pathway.  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