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   4091篇
  免费   224篇
  国内免费   20篇
耳鼻咽喉   45篇
儿科学   93篇
妇产科学   72篇
基础医学   614篇
口腔科学   79篇
临床医学   267篇
内科学   973篇
皮肤病学   103篇
神经病学   290篇
特种医学   269篇
外科学   449篇
综合类   19篇
一般理论   1篇
预防医学   230篇
眼科学   112篇
药学   359篇
中国医学   7篇
肿瘤学   353篇
  2023年   18篇
  2022年   38篇
  2021年   116篇
  2020年   59篇
  2019年   76篇
  2018年   101篇
  2017年   81篇
  2016年   110篇
  2015年   83篇
  2014年   127篇
  2013年   194篇
  2012年   282篇
  2011年   325篇
  2010年   187篇
  2009年   162篇
  2008年   270篇
  2007年   309篇
  2006年   279篇
  2005年   286篇
  2004年   222篇
  2003年   194篇
  2002年   216篇
  2001年   44篇
  2000年   50篇
  1999年   56篇
  1998年   34篇
  1997年   27篇
  1996年   22篇
  1995年   25篇
  1994年   14篇
  1993年   19篇
  1992年   45篇
  1991年   39篇
  1990年   33篇
  1989年   28篇
  1988年   25篇
  1987年   31篇
  1986年   25篇
  1985年   19篇
  1984年   8篇
  1983年   9篇
  1982年   6篇
  1979年   7篇
  1975年   4篇
  1973年   4篇
  1972年   5篇
  1971年   2篇
  1970年   3篇
  1969年   3篇
  1967年   4篇
排序方式: 共有4335条查询结果,搜索用时 46 毫秒
1.
2.
3.
PURPOSEWe aimed to evaluate mid- to long-term results of endovascular treatment for portal vein thrombosis (PVT) after living-donor liver transplantation (LDLT).METHODSThirty cases (14 males, 16 females; age range, 0.67–65 years) who underwent endovascular treatment including thrombolysis, angioplasty, stent placement, and/or collateral embolization for PVT after LDLT from 2001 to 2017 were retrospectively reviewed. Clinical and procedural data were collected and analyzed regarding the patency of the PVT site at the last follow-up date (PVT-free persistency) using Log-rank test. Results were considered statistically significant at p < 0.05.RESULTSMedian follow-up was 120 months. The technical success rate was 80% (n=24). Patency rates at 1 week and 1, 3, 6, 12, 36, and 60 months were 73%, 59%, 55%, 51%, 51%, 51%, and 51% for primary patency and 80%, 70%, 66%, 66%, 66%, 61%, and 61% for assisted patency after secondary endovascular treatment. PVT-free persistency rates regarding the subgroups were as follows: children under 12 years vs. adults, 50% vs. 68% (p = 0.42); acute vs. nonacute, 76% vs. 46% (p = 0.10); localized vs. extensive, 90% vs. 50% (p = 0.035); transileocolic approach vs. percutaneous-transhepatic approach, 71% vs. 54% (p = 0.39); and thrombolysis-based treatment vs. non-thrombolysis-based treatment, 71% vs. 44% (p = 0.12), respectively. Among technically successful cases, PVT-free persistency rate was 94% for those with hepatopetal flow in the peripheral portal vein vs. 17% for those without hepatopetal flow (p < 0.001). The only major complication occurring was pleural hemorrhage (n=1). Minor complications (i.e., fever) occurred in 18 patients (60%).CONCLUSIONIn conclusion, mid- to long-term portal patency following endovascular treatment was approximately 50%–60% in PVT patients after LDLT. PVT site patency over three months after the first endovascular treatment, localized PVT, and hepatopetal flow in the peripheral portal vein were identified as key prognostic factors for mid- to long-term portal patency.

Portal vein thrombosis (PVT) is a vascular complication of living-donor liver transplantation (LDLT), with an estimated incidence of up to 4% (1, 2). The risk of vascular complications, including PVT, is higher in LDLT compared with conventional deceased-donor liver transplantation, because of the smaller vessels, insufficient vessel length for reconstruction, neointimal proliferation, and higher risk of twisting and kinking of the vascular pedicle (3) due to smaller graft size than in deceased-donor liver transplantation. PVT after LDLT can lead to graft failure and the need for retransplantation or death (2), making immediate treatment crucial.Endovascular-based treatment is one option for treating PVT. The utility of target-focused thrombolysis, balloon angioplasty, and stent placement to restore portal flow has been reported previously (410). However, the efficacy of endovascular treatment after LDLT has only been presented in some case reports (11, 12) and the mid- to long-term outcomes remain unclear.The purpose of this study was to evaluate the technical success, feasibility, and mid- to long-term results of endovascular treatment for PVT after LDLT in our institution.  相似文献   
4.
Recently an essential role of interstitial cells of Cajal (ICC) within myenteric plexus (ICC-MY) was suggested in ascending contraction and descending relaxation in the mouse ileum. The role of ICC in these neural reflexes was examined in the distal colonic segments prepared from the wild type and c-kit mutant, W/W(V) mice, in the present study. Localized distension of the segments from the wild type mice by using a small balloon resulted in ascending contraction and descending relaxation. In the segments from the mutant mice, localized distension also induced these neural reflexes similar to those observed in the wild type mice. Immunohistochemical examination demonstrated that ICC-MY and ICC present in muscle layers (ICC-IM) were severely disrupted in the mutant mouse, but only ICC, present within submucosal plexus (ICC-SMP), remained unchanged. In the small strips with ICC-SMP absent prepared from the mutant mouse, electrical field stimulation induced contraction or relaxation in the absence or presence of atropine, respectively. It was suggested that ICC have no important role in the ascending and descending neural reflexes in the mouse distal colon, this is in direct contrast to the role of ICC-MY in the ileum.  相似文献   
5.
Left ventricular (LV) remodeling after myocardial infarction (MI) is a maladaptive process that increases the risk of heart failure and death. The myocardial phosphoinositide cycle, which is located downstream from several neurohumoral factors, plays a crucial role in LV remodeling. Our animal studies demonstrated that 1-[1-11C]butyryl-2-palmitoyl-rac-glycerol (11C-DAG) can be used to visualize regions with an activated phosphoinositide cycle. Therefore, we examined whether myocardial 11C-DAG accumulation assessed by PET is relevant to LV enlargement and systolic dysfunction in post-MI patients. METHODS: We performed PET with 11C-DAG in 13 post-anteroseptal MI patients and 4 healthy volunteers. We placed regions of interest on the noninfarcted myocardium and calculated the myocardium-to-left atrial (LA) chamber ratio of 11C-DAG accumulation. RESULTS: The myocardium-to-LA chamber ratio of 11C-DAG was significantly higher in the post-MI patients (mean +/- SD, 1.73 +/- 0.35) compared with that of the healthy volunteers (mean +/- SD, 1.25 +/- 0.13; P < 0.05). In the post-MI patients, the myocardium-to-LA chamber ratio of (11)C-DAG was significantly correlated with the LV end-diastolic volume index (r = 0.79, P < 0.01) and the plasma concentration of brain natriuretic peptide (r = 0.85, P < 0.001) and negatively correlated with the LV ejection fraction (r = -0.69, P < 0.01). CONCLUSION: These findings suggest that the myocardial 11C-DAG accumulation assessed by PET is relevant to LV enlargement, LV systolic dysfunction, and humoral activation in post-MI patients. This new imaging strategy based on intracellular signaling may contribute to the assessment and treatment of post-MI patients.  相似文献   
6.
A 67-year-old man was admitted to our hospital due to esophageal cancer. Cancer existed at the lower esophagus and subtotal esophagectomy and lymphadenectomy was performed. The postoperative course was uneventful. Pathological findings revealed moderately differentiated squamous cell carcinoma that metastasized to the abdominal lymph nodes which include the paraaortic lymph nodes. He complained of anorexia three months after the operation and was found to have multiple liver and mediastinal lymph node metastases. He was admitted for chemotherapy. Before starting chemotherapy, he suddenly died without any sign of hemorrhage or respiratory disorder. Autopsy showed metastatic lesions to the heart and mediastinal lymph nodes, liver, thoracic vertebrae, kidney, adrenal gland and heart. Metastatic nodules in the heart were on the ventricular septum where the conducting system exists. No direct invasion from the pericardium was observed. Blockade of the conducting system of the heart was considered to have caused the severe arrhythmia and sudden cardiac arrest.  相似文献   
7.
8.
We performed radiofrequency neurotomy of lumbar medial branch as a treatment of facet syndrome. Our six cases had no indication for surgical therapy, such as neuralgia, spinal canal stenosis without neurological deficit except for pain and deformed spines. Facet joint injection with regional anesthetics and steroids could not prevent their recurrent back pain. By facet rhizotomy, they could obtain relief of back pain for several months to a year. We conclude that facet rhizotomy is a more effective method for facet syndrome when a proper indication is present.  相似文献   
9.
The authors recently experienced a case of idiopathic interstitial pneumonia (IIP) that exhibited skin ulcers due to increased heparin precipitable fraction (HPF) in plasma. This case prompted us to investigate the occurrence and significance of HPF in interstitial pneumonia (IP). The subjects included patients with IIP (acute exacerbation 6 cases, chronic active stage 12 cases), IP associated with collagen vascular disease (CVD) (9 cases) and granulomatous lung diseases (7 cases). The data indicated that all of the cases with acute exacerbation of IIP exhibited increased plasma HPF values (218-951 mg/dl) compared to those of normal controls (less than 180 mg/dl). In contrast, the values ranged within normal limits in all of the cases with IP associated with CVD. In a companion study, we measured plasma HPF values in patients with lung cancer, bacterial pneumonia and diffuse panbronchiolitis. It was found that 22% of the subjects showed increased plasma HPF values. We also investigated whether there were correlations between plasma HPF and various inflammatory parameters. The data revealed that there were correlations between HPF and ESR, CRP, alpha 1-globulin, alpha 2-globulin, complement (C3) or fibrinogen. However, there was no correlation between HPF and fibronection. These results suggest that plasma HPF is valuable to evaluate the acute exacerbation of IIP, although the elevation of plasma HPF levels is not specific.  相似文献   
10.
Genetic alteration in carcinoid tumors of the lung.   总被引:1,自引:0,他引:1  
Surgically resected specimens of 13 carcinoid tumors of the lung including nine typical carcinoids and four atypical carcinoids, and eight salivary gland type carcinomas (six mucoepidermoid carcinomas and two adenoid cystic carcinomas) were analyzed regarding p53 expression, loss of heterozygosity (LOH) in chromosome 3p, 9p, and K-ras mutation. The overexpression of p53 was identified in four atypical carcinoid tumors, one mucoepidermoid carcinoma, and one adenoid cystic carcinoma, however, none of typical carcinoids showed p53 immunoreactivity. LOH in 3p14 was demonstrated in three of seven informative cases in all tumors. LOH in 9p was demonstrated in two of five informative cases in all tumors. Two of three cases with LOH at 3p14 had a poor prognosis, one of which also had LOH at 9p. No mutation of the K-ras gene was observed in any of these tumors. These data thus indicate that p53 overexpression might distinguish atypical carcinoid tumors from typical tumors and might therefore be useful as an adjunct modality in the differential diagnosis of pulmonary carcinoid tumors. The presence of LOH at 3p14 or 9p may thus help to identify lung cancer patients with a poor prognosis.  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