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   2616篇
  免费   199篇
  国内免费   3篇
耳鼻咽喉   38篇
儿科学   69篇
妇产科学   67篇
基础医学   370篇
口腔科学   41篇
临床医学   277篇
内科学   541篇
皮肤病学   38篇
神经病学   182篇
特种医学   227篇
外国民族医学   26篇
外科学   348篇
综合类   31篇
一般理论   1篇
预防医学   152篇
眼科学   53篇
药学   154篇
中国医学   3篇
肿瘤学   200篇
  2022年   25篇
  2021年   43篇
  2020年   29篇
  2019年   52篇
  2018年   75篇
  2017年   51篇
  2016年   49篇
  2015年   58篇
  2014年   87篇
  2013年   109篇
  2012年   164篇
  2011年   146篇
  2010年   99篇
  2009年   82篇
  2008年   134篇
  2007年   131篇
  2006年   117篇
  2005年   118篇
  2004年   126篇
  2003年   117篇
  2002年   98篇
  2001年   88篇
  2000年   77篇
  1999年   68篇
  1998年   34篇
  1997年   23篇
  1996年   20篇
  1995年   24篇
  1994年   17篇
  1993年   23篇
  1992年   54篇
  1991年   40篇
  1990年   32篇
  1989年   48篇
  1988年   20篇
  1987年   40篇
  1986年   45篇
  1985年   26篇
  1984年   19篇
  1983年   15篇
  1982年   10篇
  1981年   9篇
  1979年   14篇
  1975年   12篇
  1974年   18篇
  1973年   12篇
  1972年   14篇
  1971年   13篇
  1970年   10篇
  1969年   13篇
排序方式: 共有2818条查询结果,搜索用时 15 毫秒
971.

Purpose

Toward an efficient clinical management of hepatocellular carcinoma (HCC), we propose a classification framework dedicated to tumor necrosis rate estimation from dynamic contrast-enhanced CT scans. Based on machine learning, it requires weak interaction efforts to segment healthy, active and necrotic liver tissues.

Methods

Our contributions are two-fold. First, we apply random forest (RF) on supervoxels using multi-phase supervoxel-based features that discriminate tissues based on their dynamic in response to contrast agent injection. Second, we extend this technique in a hierarchical multi-scale fashion to deal with multiple spatial extents and appearance heterogeneity. It translates in an adaptive data sampling scheme combining RF and hierarchical multi-scale tree resulting from recursive supervoxel decomposition. By concatenating multi-phase features across the hierarchical multi-scale tree to describe leaf supervoxels, we enable RF to automatically infer the most informative scales without defining any explicit rules on how to combine them.

Results

Assessment on clinical data confirms the benefits of multi-phase information embedded in a multi-scale supervoxel representation for HCC tumor segmentation.

Conclusion

Dedicated but not limited only to HCC management, both contributions reach further steps toward more accurate multi-label tissue classification.
  相似文献   
972.
973.
974.
In principle, destruction of tumor cells in vivo by oncolytic agents would release the entire repertoire of tumor antigens in their natural forms, leading to effective antitumor immunity. This goal has been elusive despite extensive testing of numerous strategies. We developed a doubly fusogenic oncolytic herpes simplex virus (Synco-2D) that kills tumor cells by a unique dual mechanism combining direct cytolysis with syncytial formation induced by cell membrane fusion. A single intratumor injection of Synco-2D induced strong antitumor immunity against an otherwise nonimmunogenic murine mammary tumor growing in immune-competent mice. CD8+ T cells were the primary mediators of immunity, contributing to the destruction of both primary and metastatic tumors. We conclude that the fusogenic capacity of Synco-2D enables it to elicit antitumor immunity exceeding that induced by more conventional oncolytic viruses.  相似文献   
975.

Introduction

Thoracotomy as surgical approach for esophageal atresia treatment entails the risk of deformation of the rib cage and consequently secondary thoracogenic scoliosis. The aim of our study was to assess these thoracic wall anomalies on a large national cohort and search for factors influencing this morbidity.

Materials and methods

Pediatric surgery departments from our national network were asked to send recent thoracic X-ray and operative reports for patients born between 2008 and 2010 with esophageal atresia. The X-rays were read in a double-blind manner to detect costal and vertebral anomalies.

Results

Among 322 inclusions from 32 centers, 110 (34.2%) X-rays were normal and 25 (7.7%) displayed thoracic malformations, including 14 hemivertebrae. We found 187 (58.1%) sequelae of surgery, including 85 costal hypoplasia, 47 other types of costal anomalies, 46 intercostal space anomalies, 21 costal fusions and 12 scoliosis, with some patients suffering from several lesions. The rate of patients with these sequelae was not influenced by age at intervention, weight at birth, type of atresia, number of thoracotomy or size of the center. The rate of sequelae was higher following a classical thoracotomy (59.1%), whatever the way that thoracotomy was performed, compared to nonconverted thoracoscopy (22.2%; p = 0.04).

Conclusion

About 60 % of the patients suffered from a thoracic wall morbidity caused by the thoracotomy performed as part of surgical treatment of esophageal atresia. Minimally invasive techniques reduced thoracic wall morbidity. Further studies should be carried out to assess the potential benefit of minimally invasive approaches to patient pulmonary functions and on the occurrence of thoracogenic scoliosis in adulthood.

Levels of evidence

Level III retrospective comparative treatment study.  相似文献   
976.

Background

To report on the outcome of patients diagnosed with central nervous system haemangiopericytoma (HPC) or solitary fibrous tumours (SFT) and identify factors that may influence recurrence and survival.

Material and methods

Between January 1977 and December 2016, a retrospective search identified 22 HPCs/SFTs. The patients underwent a total of 40 surgical resections and 63.6% received radiotherapy. Median follow-up was 7.8 years.

Results

Six patients (27.3%) were re-operated for tumour recurrence. At the end of the study, 15 patients (68.2%) had no residual tumour on the last imaging. Surgical recurrence-free survival at 5 years was 77.4%, [95% CI: 60.1–99.8]. None of the investigated variables was associated with recurrence. At the end of the study, 5 patients were deceased (22.7%) and only 10 patients (45.5%) had no residual tumour on the last imaging and were alive. Overall survival at 5 years was 95%, [95% CI: 85.9–100]. None of the investigated variables was associated with overall survival. Patients who received radiotherapy demonstrated neither a reduced risk of surgical recurrence (P = 0.378) nor a longer overall survival (P = 0.405).

Conclusion

SFTs/HPCs are associated with a significant risk of recurrence that may reduce the survival. Even if we could not demonstrate their benefit in this limited series, we believe that tailored maximal tumour resection on initial surgery is beneficial and that adjuvant RT is useful for tumours displaying grade II or III, even in case of complete removal.  相似文献   
977.
CD40 ligand (CD40L) is a good candidate molecule for the immunotherapy of B cell malignancies including B-chronic lymphocytic leukemia (B-CLL), because it may increase the capacity of the malignant cells to present tumor antigens. However, efforts to manipulate expression of the human CD40L (hCD40L) molecule have foundered on problems associated with lack of consistent gene transfer into the malignant target cells. We now describe a new, highly reproducible method for inducing hCD40L surface expression on malignant B cells, which is dependent on intercellular transfer of the hCD40L protein from donor gene-modified fibroblasts to patient tumor cells. Ten B-CLL samples were cocultured with MRC-5 fibroblasts (a human embryonic lung cell line) previously transduced with an adenoviral vector encoding the hCD40L gene. The malignant cells expressed high levels of surface hCD40L, B7-1, B7-2, and ICAM-1 after coculture. Upregulation of B7-1 and B7-2 was cycloheximide inhibitable and was a consequence of CD40 activation. However, inhibition of protein synthesis had no effect on the ability of B-CLL cells to acquire surface expression of hCD40L. hCD40L surface expression required cell-to-cell contact, but was independent of CD40 engagement. hCD40L transfer was not mediated by membrane fusion. The transferred hCD40L was functionally intact and B-CLL cells expressing this molecule induced increased interferon-gamma production from autologous peripheral blood T lymphocytes. This approach does not use any direct gene transfer to primary leukemia cells and can readily be scaled up for production of clinical B-CLL vaccines.  相似文献   
978.

Purpose

Few outcome data are available about temperature management after intraoperative cardiac arrest (IOCA). We describe targeted temperature management (TTM) (32–34 °C) modalities, adverse events, and association with 1-year functional outcome in patients with IOCA.

Methods

Patients admitted to 11 ICUs after IOCA in 2008–2013 were studied retrospectively. The main outcome measure was 1-year functional outcome.

Results

Of the 101 patients [35 women and 66 men; median age, 62 years (interquartile range, 42–72)], 68 (67.3%) were ASA PS I to III and 57 (56.4%) had emergent surgery. First recorded rhythms were asystole in 44 (43.6%) patients, pulseless electrical activity in 36 (35.6%), and ventricular fibrillation/tachycardia in 20 (19.8%). Median times from collapse to cardiopulmonary resuscitation and return of spontaneous circulation (ROSC) were 0 min (0–0) and 10 min (4–20), respectively. The 30 (29.7%) patients who received TTM had an increased risk of infection (P = 0.005) but not of arrhythmia, bleeding, or metabolic/electrolyte disorders. By multivariate analysis, one or more defibrillation before ROSC was positively associated with a favorable functional outcome at 1-year (OR 3.06, 95% CI 1.05–8.95, P = 0.04) and emergency surgery was negatively associated with 1-year favorable functional outcome (OR 0.36; 95% CI 0.14–0.95, P = 0.038). TTM use was not independently associated with 1-year favorable outcome (OR 0.82; 95% CI 0.27–2.46, P = 0.72).

Conclusions

TTM was used in less than one-third of patients after IOCA. TTM was associated with infection but not with bleeding or coronary events in this setting. TTM did not independently predict 1-year favorable functional outcome after IOCA in this study.
  相似文献   
979.
980.
Purpose We used small animal positron emission tomography (PET) imaging to monitor the time-course of tumor metabolic response to hormone and chemotherapy in a murine model of hormone-sensitive breast cancer. Procedures Estrogen receptor positive murine mammary carcinomas were inoculated in Balb/c mice. Small animal PET imaging using 2-deoxy-2-[F-18]fluoro-d-glucose (FDG) was used to assess tumor metabolic activity. Imaging was done before and at days 1, 7, and 14 after the administration of doxorubicin, methotrexate, letrozole, or placebo. The tumor uptake of FDG was calculated from a region-of-interest drawn around the tumor. Results All treatments resulted in a decrease in tumor growth rate and end volume compared to untreated control. FDG uptake was also markedly decreased after treatment although a flare reaction was observed on PET at day 7, the intensity of which varied according to the treatment modality. Conclusion PET imaging is sensitive to detect early changes associated with therapy in murine breast cancer models. A flare reaction was observed 7 days after the initiation of therapy.  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