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   1941篇
  免费   108篇
  国内免费   22篇
耳鼻咽喉   1篇
儿科学   156篇
妇产科学   50篇
基础医学   199篇
口腔科学   48篇
临床医学   167篇
内科学   439篇
皮肤病学   25篇
神经病学   57篇
特种医学   472篇
外科学   172篇
综合类   29篇
预防医学   46篇
眼科学   28篇
药学   56篇
中国医学   3篇
肿瘤学   123篇
  2023年   3篇
  2022年   5篇
  2021年   18篇
  2020年   11篇
  2019年   11篇
  2018年   23篇
  2017年   13篇
  2016年   26篇
  2015年   34篇
  2014年   33篇
  2013年   74篇
  2012年   42篇
  2011年   43篇
  2010年   86篇
  2009年   71篇
  2008年   46篇
  2007年   35篇
  2006年   57篇
  2005年   34篇
  2004年   26篇
  2003年   30篇
  2002年   26篇
  2001年   27篇
  2000年   28篇
  1999年   41篇
  1998年   136篇
  1997年   119篇
  1996年   124篇
  1995年   91篇
  1994年   77篇
  1993年   83篇
  1992年   26篇
  1991年   25篇
  1990年   18篇
  1989年   60篇
  1988年   48篇
  1987年   51篇
  1986年   51篇
  1985年   52篇
  1984年   25篇
  1983年   35篇
  1982年   34篇
  1981年   20篇
  1980年   38篇
  1979年   21篇
  1978年   16篇
  1977年   17篇
  1976年   23篇
  1975年   25篇
  1966年   2篇
排序方式: 共有2071条查询结果,搜索用时 15 毫秒
71.

Introduction

The high mortality and morbidity associated with resection for oesophagogastric malignancy has resulted in a conservative approach to the postoperative management of this patient group. In August 2009 we introduced an enhanced recovery after surgery (ERAS) pathway tailored to patients undergoing resection for oesophagogastric malignancy. We aimed to assess the impact of this change in practice on standard clinical outcomes.

Methods

Two cohorts were studied of patients undergoing resection for oesophagogastric malignancy before (August 2008 – July 2009) and after (August 2009 – July 2010) the implementation of the ERAS pathway. Data were collected on demographics, interventions, length of stay, morbidity and in-hospital mortality.

Results

There were 53 and 55 oesophagogastric resections undertaken respectively for malignant disease in each of the study periods. The median length of stay for both gastric and oesophageal resection decreased from 15 to 11 days (Mann– Whitney U, p<0.001) following implementation of the ERAS pathway. There was no significant increase in morbidity (gastric resection 23.1% vs 5.3% and oesophageal resection 25.9% vs 16.7%) or mortality (gastric resection no deaths and oesophageal resection 1.8% vs 3.6%) associated with the changes. There was a significant decrease in the number of oral contrast studies used following oesophageal resection, with a reduction from 21 (77.8%) in 2008–2009 to 6 (16.7%) in 2009–2010 (chi-squared test, p<0.0001).

Conclusions

The introduction of an enhanced recovery programme following oesophagogastric surgery resulted in a significant decrease in length of median patient stay in hospital without a significant increase in associated morbidity and mortality.  相似文献   
72.
Nausea and vomiting are among the most common symptoms encountered in medicine as either symptoms of disease or side effects of treatments. Developing novel anti-emetics and identifying emetic liability in novel chemical entities rely on models that can recreate the complexity of these multi-system reflexes. Animal models (especially the ferret and dog) are the current gold standard; however, the selection of appropriate models is still a matter of debate, especially when studying the subjective human sensation of nausea. Furthermore, these studies are associated with animal suffering. Here, following a recent workshop held to review the utility of animal models in nausea and vomiting research, we discuss the limitations of some of the current models in the context of basic research, anti-emetic development and emetic liability detection. We provide suggestions for how these limitations may be overcome using non-animal alternatives, including greater use of human volunteers, in silico and in vitro techniques and lower organisms.  相似文献   
73.
74.
75.

Background  

In many stroke patients arm function is limited, which can be related to an abnormal coupling between shoulder and elbow joints. The extent to which this can be translated to activities of daily life (ADL), in terms of muscle activation during ADL-like movements, is rather unknown. Therefore, the present study examined the occurrence of abnormal coupling on functional, ADL-like reaching movements of chronic stroke patients by comparison with healthy persons.  相似文献   
76.
77.
Background: Thyroid cancer is the most common endocrine malignancy, and exact causes remain unknown. The role of CYP450 1A1 (CYP1A1) in cancer initiation and progression has been investigated. The aim of this work was to analyze, for the first time, CYP1A1 gene expression and its relationship with several clinicopathological factors in Mexican patients diagnosed with thyroid cancer. Materials and Methods: Realtime PCR analysis was conducted on 32 sets of thyroid tumors and benign pathologies. Expression levels were tested for correlations with clinical and pathological data. All statistical analysis were performed using GraphPad Prism version 3.0 software. Results: We found that female gender was associated with thyroid cancer risk (P<0.05). A positive relationship was identified between CYP1A1 mRNA levels and the presence of chronic disease, alcohol use, tumor size, metastasis and an advanced clinical stage (P<0.05). Conclusions: The results suggest that CYP1A1 gene expression could be used as a marker for thyroid cancer.  相似文献   
78.
Perinatal arterial ischaemic stroke (PAIS) affects between 1:2300 and 1:4000 births, so most paediatricians and neonatologists will see a number of cases during their working life. The exact cause of PAIS in an individual usually is unknown, and discussion may occur about whether prothrombotic investigations, aspirin or anticoagulation are needed. The causes, investigation and treatment of PAIS are completely different from stroke in the older paediatric and adult group. Outcome tends to be good, although cerebral palsy may be seen in up to 30% of cases, epilepsy in 15–25% and cognitive problems may also occur. Fortunately, EEG and MRI can help identify those children with PAIS at the highest risk of neuro-developmental difficulties. This paper reviews what we know about the potential mechanisms causing PAIS, what investigations are necessary, and the likely outcome for the child.  相似文献   
79.
A Lucci  T Y Han  Y Y Liu  A E Giuliano  M C Cabot 《Cancer》1999,86(2):300-311
BACKGROUND: To provide insight for the development of more effective clinical agents, the authors attempted to elucidate the mechanisms of action of multidrug resistance (MDR) modulators. Previously, the authors found that MDR modulators blocked the conversion of ceramide to glucosylceramide in MDR cells, thereby enhancing cytotoxicity. Because ceramide is a critical component of the apoptosis signaling cascade, the current study examined the impact of therapy using agents that elicit ceramide formation combined with agents that block ceramide glycosylation. METHODS: Doxorubicin-resistant human breast carcinoma cells (MCF-7-AdrR) were treated with either doxorubicin, tamoxifen, cyclosporine A, or the cyclosporine A analog SDZ PSC 833 (PSC 833) or with combinations thereof, and ceramide and glucosylceramide metabolisms were measured by cell radiolabeling. Cell viability was quantitated spectrophotometrically and apoptosis was evaluated analyzing DNA integrity by gel electrophoresis. RESULTS: Whereas cyclosporine A blocked the generation of glucosylceramide in MCF-7-AdrR cells, a chemical cousin, PSC 833, elicited a 3-fold increase in glucosylceramide and a 5-fold increase in ceramide levels at 24 hours. The PSC 833 response was time-dependent(as early as 30 minutes) and dose-dependent (as low as 0.1 microM). The appearance of ceramide foreran the generation of glucosylceramide. Sphingomyelin levels were not decreased in response to PSC 833; however, Fumonisin B1, a ceramide synthase inhibitor, blocked PSC 833-induced ceramide generation. Adding tamoxifen, which blocks ceramide glycosylation, to the PSC 833 regimen boosted ceramide levels 11-fold over controls and caused DNA fragmentation. A 3-component regimen comprised of tamoxifen, doxorubicin, and PSC 833 increased ceramide levels 26-fold and brought cell viability to zero. CONCLUSIONS: These results demonstrate that MDR modulators can be used separately, in combination, or in conjunction with chemotherapy at clinically relevant concentrations to manipulate cellular ceramide levels and restore sensitivity in the drug resistant setting. As such, this represents a new direction in the treatment of cancer.  相似文献   
80.
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