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   2527篇
  免费   114篇
  国内免费   12篇
耳鼻咽喉   17篇
儿科学   86篇
妇产科学   25篇
基础医学   200篇
口腔科学   72篇
临床医学   128篇
内科学   666篇
皮肤病学   67篇
神经病学   187篇
特种医学   210篇
外科学   438篇
综合类   13篇
预防医学   78篇
眼科学   22篇
药学   138篇
中国医学   5篇
肿瘤学   301篇
  2023年   7篇
  2022年   19篇
  2021年   41篇
  2020年   22篇
  2019年   39篇
  2018年   53篇
  2017年   39篇
  2016年   41篇
  2015年   49篇
  2014年   75篇
  2013年   72篇
  2012年   148篇
  2011年   163篇
  2010年   77篇
  2009年   81篇
  2008年   162篇
  2007年   160篇
  2006年   164篇
  2005年   165篇
  2004年   155篇
  2003年   140篇
  2002年   146篇
  2001年   82篇
  2000年   58篇
  1999年   64篇
  1998年   33篇
  1997年   31篇
  1996年   20篇
  1995年   24篇
  1994年   15篇
  1993年   8篇
  1992年   37篇
  1991年   24篇
  1990年   24篇
  1989年   21篇
  1988年   16篇
  1987年   24篇
  1986年   20篇
  1985年   14篇
  1984年   15篇
  1983年   11篇
  1982年   8篇
  1981年   5篇
  1980年   6篇
  1979年   7篇
  1978年   12篇
  1977年   9篇
  1975年   7篇
  1974年   5篇
  1973年   5篇
排序方式: 共有2653条查询结果,搜索用时 343 毫秒
81.
82.
Squamous cell carcinoma of the anal canal in children is rare. To date, the etiology and outcome of this condition have been not fully understood. Here, we report an 11‐year‐old child with anal canal cancer who had concomitant disorders of sex development. Radiotherapy followed by salvage surgery achieved disease‐free survival of 3 years. Since overexpression of cell cycle regulatory protein p16 was immunohistochemically evident in tumor tissue, human papillomavirus infection was considered as a causative factor in the carcinogenesis.  相似文献   
83.

Purpose

To present our experience in abdominal transplantations to manage unresectable abdominal neoplasms in children and to describe the role of extensive surgeries in such cases.

Methods

This is a retrospective study of 22 abdominal transplantations in 21 patients for abdominal tumors over 16 years. Transplantation techniques included liver transplant (LT), multivisceral transplant (MVTx), and intestinal autotransplant (IA). Follow-up intervals ranged from 0.3 to 168 months (median 20 months).

Results

LT alone was performed in 15 patients for primary malignant (11) and benign (4) liver tumors. Pathological classification included HB hepatoblastoma (6), HCC hepatocellular cancer (3), hepatic epithelioid hemangioendothelioma HEH (1), angiosarcoma (1), benign vascular tumors (3), and adenoma (1). IA was performed in four patients for lesions involving the root of the mesentery; tumors of the head of pancreas (3) and mesenteric hemangioma (1). MVTx was performed in 2 patients for malignancies; pancreaticoblastoma (1), recurrent hepatoblastoma (1), and in one patient as a rescue procedure after IA failure. Four of the eleven patients who underwent LT for malignant liver tumor had metastatic disease at presentation. Six of them died of recurrent neoplasm (3), transplant-related complications (2), and underlying disease (1). All LT patients who had benign tumors are alive with functioning grafts. All IA patients survived and are on an oral diet, with one patient requiring TPN supplementation. One of the three patients who underwent MVTx died of metastatic disease.

Conclusions

Allo/auto transplantation for abdominal tumors is a valuable modality when conventional treatments fail or are not feasible.
  相似文献   
84.
85.
Aims/IntroductionThe mechanisms underlying hypertriglyceridemia‐induced impaired glucose tolerance in Japanese individuals remain unclear. We aimed to evaluate the effect of hypertriglyceridemia on glucose metabolism in comparison with that of increased low‐density lipoprotein or decreased high‐density lipoprotein levels and to elucidate the sex differences in hypertriglyceridemia‐related dietary intake among Japanese individuals.Materials and MethodsWe randomly selected 898 (384 men and 514 women) participants aged 40–78 years in the Gifu Diabetes Study; those taking medication for dyslipidemia or diabetes mellitus were excluded. Serum levels of glucose metabolism parameters and the food frequency were measured cross‐sectionally. The glycated hemoglobin was measured again after 5 years.ResultsGlucose metabolism parameters and the percentage of individuals with impaired glucose tolerance were significantly higher in the high triglyceride group in men and women. Similar trends were observed in the low high‐density lipoprotein group, but only in men. Meanwhile, only the homeostasis model assessment of insulin resistance was higher in the high low‐density lipoprotein group. In non‐obese men, the percentage of energy intake from alcohol per total daily energy intake was significantly greater in the high triglyceride group. In obese women, the total energy intake was significantly greater in the high triglyceride group. At the 5‐year follow up, the risk of elevated glycated hemoglobin levels with hypertriglyceridemia was increased in men.ConclusionsHypertriglyceridemia is a stronger risk factor for impaired glucose tolerance than increased low‐density lipoprotein or decreased high‐density lipoprotein. For dietary habits, increased daily alcohol energy intake in non‐obese men and increased total energy intake in obese women were associated with hypertriglyceridemia.  相似文献   
86.
87.
bcl-2 overexpression promotes myocyte proliferation   总被引:9,自引:0,他引:9       下载免费PDF全文
To determine the influence of Bcl-2 on the developmental biology of myocytes, we analyzed the population dynamics of this cell type in the heart of transgenic (TG) mice overexpressing Bcl-2 under the control of the alpha-myosin heavy chain promoter. TG mice and non-TG (wild type, WT) mice were studied at 24 days, 2 months, and 4 months after birth. Bcl-2 overexpression produced a significant increase in the percentage of cycling myocytes and their mitotic index. These effects were strictly connected to the expression of the transgene, as demonstrated in isolated myocytes. The formation of mitotic spindle and contractile ring was identified in replicating cells. These typical aspects of mitosis were complemented with the demonstration of karyokinesis and cytokinesis to provide structural evidence of cell division. Apoptosis was low at all ages and was not affected by Bcl-2. The higher cell replication rate in TG was conditioned by a decrease in the expression of the cell-cycle inhibitors, p21(WAF1) and p16(INK4a), and by an increase in Mdm2-p53 complexes. In comparison with WT, TG had 0.4 x 10(6), 0.74 x 10(6), and 1.2 x 10(6) more myocytes in the left ventricle at 24 days, 2 months, and 4 months, respectively. Binucleated myocytes were 12% and 25% larger in WT than in TG mice at 2 and 4 months of age. Taken together, these observations reveal a previously uncharacterized replication-enhancing function of Bcl-2 in myocytes in vivo in the absence of stressful conditions.  相似文献   
88.
An unresolved question in cardiac biology is whether distinct signaling pathways are responsible for the development of pathological and physiological cardiac hypertrophy in the adult. Physiological hypertrophy is characterized by a normal organization of cardiac structure and normal or enhanced cardiac function, whereas pathological hypertrophy is associated with an altered pattern of cardiac gene expression, fibrosis, cardiac dysfunction, and increased morbidity and mortality. The elucidation of signaling cascades that play distinct roles in these two forms of hypertrophy will be critical for the development of more effective strategies to treat heart failure. We examined the role of the p110alpha isoform of phosphoinositide 3-kinase (PI3K) for the induction of pathological hypertrophy (pressure overload-induced) and physiological hypertrophy (exercise-induced) by using transgenic mice expressing a dominant negative (dn) PI3K(p110alpha) mutant specifically in the heart. dnPI3K transgenic mice displayed significant hypertrophy in response to pressure overload but not exercise training. dnPI3K transgenic mice also showed significant dilation and cardiac dysfunction in response to pressure overload. Thus, PI3K(p110alpha) appears to play a critical role for the induction of physiological cardiac growth but not pathological growth. PI3K(p110alpha) also appears essential for maintaining contractile function in response to pathological stimuli.  相似文献   
89.
90.
Although considerable attention has focused on obesity, insulin resistance and abnormal lipid metabolism as coronary risk factors, it remains unclear how these pathogenic factors affect the inflammatory response after myocardial ischemia-reperfusion. This study was conducted to evaluate whether these metabolic disorders exacerbate myocardial ischemia-reperfusion injury, and to determine if ischemia-reperfusion injury could be modified with the thiazolidinedione, pioglitazone. Experiments were performed in KK-Ay and C57BL/6J mice subjected to 40 min of ischemia followed by reperfusion. Infiltration of inflammatory cells in ischemic myocardium, and infarct size 3 days after reperfusion were significantly higher in KK-Ay than C57BL/6J mice (p < 0.05 and p < 0.001, respectively). Furthermore, expression of chemokines, inflammatory cytokines and extracellular matrix proteins in ischemic myocardium was significantly higher in KK-Ay than C57BL/6J mice 1 day after reperfusion. Pioglitazone treatment of KK-Ay mice for 14 days significantly reduced the accumulation of inflammatory cells in ischemic myocardium, and infarct size 3 days after reperfusion compared to vehicle treatment (p < 0.05 and p < 0.05, respectively). Pioglitazone also attenuated expression of chemokines, inflammatory cytokines and extracellular matrix proteins in ischemic myocardium 1 day after reperfusion. In vitro experiments demonstrated that tumor necrosis factor-α (TNF-α) was significantly higher in cultured peritoneal macrophages from KK-Ay than C57BL/6J mice, and pioglitazone significantly reduced TNF-α in macrophages from both types of mice. These findings suggest that metabolic disorders exacerbate ischemia-reperfusion injury as a result of overexpression of inflammatory mediators, and this effect might be improved, in part by the anti-inflammatory effects of pioglitazone.  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