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   6375篇
  免费   321篇
  国内免费   44篇
耳鼻咽喉   41篇
儿科学   100篇
妇产科学   58篇
基础医学   643篇
口腔科学   115篇
临床医学   408篇
内科学   1916篇
皮肤病学   264篇
神经病学   254篇
特种医学   259篇
外科学   1086篇
综合类   55篇
预防医学   152篇
眼科学   339篇
药学   426篇
中国医学   32篇
肿瘤学   592篇
  2023年   57篇
  2022年   97篇
  2021年   161篇
  2020年   68篇
  2019年   102篇
  2018年   126篇
  2017年   118篇
  2016年   145篇
  2015年   160篇
  2014年   219篇
  2013年   217篇
  2012年   376篇
  2011年   404篇
  2010年   216篇
  2009年   204篇
  2008年   317篇
  2007年   325篇
  2006年   312篇
  2005年   321篇
  2004年   310篇
  2003年   280篇
  2002年   271篇
  2001年   162篇
  2000年   133篇
  1999年   146篇
  1998年   77篇
  1997年   57篇
  1996年   49篇
  1995年   45篇
  1994年   57篇
  1993年   35篇
  1992年   125篇
  1991年   130篇
  1990年   126篇
  1989年   113篇
  1988年   90篇
  1987年   83篇
  1986年   72篇
  1985年   76篇
  1984年   58篇
  1983年   28篇
  1982年   21篇
  1981年   20篇
  1980年   17篇
  1979年   28篇
  1978年   25篇
  1977年   18篇
  1974年   20篇
  1968年   17篇
  1966年   14篇
排序方式: 共有6740条查询结果,搜索用时 31 毫秒
41.
42.
We describe the histopathologic and ultrastructural evidence of choriovitreal neovascularization in the peripheral fundus of a non-vitrectomized eye with proliferative diabetic retinopathy (PDR). One eye with PDR was surgically enucleated because of neovascular glaucoma and studied with light and electron microscopy. The eye had neovascular membranes at the ora serrata of the peripheral fundus. The newly formed vessels originated from the choroid, passed through Bruch's membrane and the retina, and extended into the vitreous. These vessels had either developing or mature characteristics. The endothelial cells of the developing vessels contained a bulky cytoplasm with many intracytoplasmic filaments, ribosomes and rough endoplasmic reticulum. Budding endothelial cells were frequently found in the developing vessels. The endothelial cells of the mature vessels had attenuated cytoplasm and fenestrations with diaphragms. These observations suggest that choriovitreal neovascularization in the peripheral fundus is one of the features of PDR.  相似文献   
43.
BACKGROUND: Hyperinsulinemia, which is usually related to insulin resistance, is considered to be an important risk factor for coronary artery disease. Our study examines the influence of portal delivery of endogenous insulin after pancreas transplantation on plasma lipid metabolism, as compared with systemic delivery of insulin. METHOD: Pancreas was transplanted heterotopically in normal rats by anastomosis of the donor portal vein to the recipient portal vein (PPTx) or inferior vena cava (CPTx) as an in vivo model of endogenous hyperinsulinemia. RESULTS: The mean value of plasma insulin concentration of CPTx and PPTx rats was 149 and 165% that of control rats, whereas the plasma glucose concentration of CPTx and PPTx rats did not differ significantly from that of control rats. Plasma triglyceride (TG) concentrations were significantly lower in both PPTx and CPTx rats than control rats. During the intravenous glucose tolerance test, the area under the insulin concentration curves of CPTx and PPTx rats was 204 and 215% that of control rats, and they were correlated negatively with plasma TG concentrations. Plasma cholesterol and TG concentrations were significantly lower in PPTx rats than in control and CPTx rats. CONCLUSIONS: Chronic hyperinsulinemia has a dose-dependent inhibitory effect on the regulation of plasma TG concentrations in rats with a transplanted pancreas. Significant lower lipid levels in PPTx rats than in CPTx rats suggest that portal delivery of insulin from the transplanted pancreas is relatively preventive for the atherosclerotic process as compared with systemic delivery of insulin.  相似文献   
44.
To elucidate the early events of blood-borne metastasis under actual blood flow, real-time trafficking of RAW117 large cell lymphoma cells, namely parental RAW117-P and liver-metastatic RAW117-H10 cells, was investigated using positron emission tomography (PET). Both types of cells accumulated in the liver immediately after injection via the portal vein, and were eliminated from the liver time-dependently. The elimination rate of RAW117-H10 cells, however, was slower than that of RAW117-P cells, suggesting that RAW117-H10 cells interact more strongly with hepatic sinusoidal endothelium than the parental cells. This result correlated with the metastatic potential of these cells: RAW117-H10 cells metastasized in the liver to a greater extent than RAW117-P cells after injection via this route. To investigate the role of sialylglycoconjugates in the interaction of RAW117-H10 cells with the hepatic endothelium after injection via the portal vein, the trafficking of RAW117-H10 cells was examined after the cells had been treated with sialidase. The elimination rate of RAW117-H10 cells from liver was observed to be greatly accelerated by sialidase treatment. To elucidate what kind of sialylglycoconjugates is related to this phenomenon, we analyzed the distribution of sialyl Lewis A and sialyl Lewis X antigens of both sublines of RAW117 by using flow cytometry. RAW117-H10 cells were found to express a much higher level of sialyl Lewis A than RAW117-P cells, whereas the amount of sialyl Lewis X did not differ significantly. These findings suggest that some sialylglycoconjugates, perhaps sialyl Lewis A in particular, play an important role in the initial interaction of RAW117-H10 cells with the hepatic endothelium, leading to metastasis.  相似文献   
45.
46.
A case of aconitine poisoning saved with cardiopulmonary bypass   总被引:1,自引:0,他引:1  
"Torikabuto" is a kind of plant which contains deadly poison. Its ingredient is aconitine alkaloids. We report a case of aconitine poisoning with fatal arrhythmia and acute pulmonary edema who was saved with cardio pulmonary bypass. A 41-year-old male ate to mistake "Torikabuto" for wild plant. He developed symptoms of dysarthria and admitted to our hospital. He developed ventricular tachycardia and fibrillation soon after his admission. Then he developed cardiogenic shock. He was resuscitated and supported with a percutaneous cardio pulmonary bypass. Ventricular tachycardia disappeared 24 hours after admittion. About 1 week later, cardio pulmonary bypass was terminated and about 3 months later, he discharged from our hospital.  相似文献   
47.
48.
Trousseau syndrome-related cerebral infarction rarely occurs during chemotherapy in patients with gastrointestinal (GI) cancer, and its clinical features remain unclear. The present study aimed to examine the clinical features of Trousseau syndrome-related cerebral infarction developed during chemotherapy for GI cancer. The present retrospective cohort study consecutively enrolled 878 patients with unresectable GI cancer who received chemotherapy at the Multidisciplinary Treatment Cancer Center, Kurume University Hospital (Kurume, Japan) between April 2014 and March 2020. Patients with colorectal cancer (n=308) were the most common, followed by those with pancreatic (n=242), gastric (n=222) and biliary tract (n=59) cancer, neuroendocrine tumors (n=34) and duodenal cancer (n=11). Among the 878 patients, Trousseau syndrome-related cerebral infarction occurred in 8 (0.9%) patients with a median age of 70.5 years (range, 58–75 years), and 50% of the patients were male (4/8). In total, 3 patients had gastric cancer, 3 had pancreatic cancer and 2 had biliary tract cancer. A greater percentage of patients with Trousseau syndrome-related cerebral infarction had hyperlipidemia (38.0%) than those without (8.2%; P=0.005). Hyperlipidemia was a risk factor for occurrence of Trousseau syndrome-related cerebral infarction with an odds ratio of 7.009 (95% confidence interval, 1.785-27.513). Trousseau syndrome-related cerebral infarction developed during GI chemotherapy was rare and hyperlipidemia may predict its onset.  相似文献   
49.
Over the past 20 years, there has been remarkable progress in the diagnosis and treatment of congenital hyperinsulinism (CHI). These advances have been supported by the understanding of the molecular mechanism and the development of diagnostic modalities to identify the focal form of ATP‐sensitive potassium channel CHI. Many patients with diazoxide‐unresponsive focal CHI have been cured by partial pancreatectomy without developing postsurgical diabetes mellitus. Important novel findings on the genetic basis of the other forms of CHI have also been obtained, and several novel medical treatments have been explored. However, the management of patients with CHI is still far from ideal. First, state‐of‐the‐art treatment is not widely available worldwide. Second, it appears that the management strategy needs to be adjusted according to the patient's ethnic group. Third, optimal management of patients with the diazoxide‐unresponsive, diffuse form of CHI is still insufficient and requires further improvement. In this review, we describe the current landscape of this disorder, discuss the racial disparity of CHI using Japanese patients as an example, and briefly note unanswered questions and unmet needs that should be addressed in the near future.  相似文献   
50.
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