全文获取类型
收费全文 | 8965篇 |
免费 | 582篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 173篇 |
儿科学 | 266篇 |
妇产科学 | 136篇 |
基础医学 | 1109篇 |
口腔科学 | 117篇 |
临床医学 | 782篇 |
内科学 | 2444篇 |
皮肤病学 | 140篇 |
神经病学 | 782篇 |
特种医学 | 376篇 |
外国民族医学 | 7篇 |
外科学 | 1424篇 |
综合类 | 45篇 |
一般理论 | 1篇 |
预防医学 | 584篇 |
眼科学 | 78篇 |
药学 | 559篇 |
中国医学 | 9篇 |
肿瘤学 | 562篇 |
出版年
2023年 | 47篇 |
2022年 | 79篇 |
2021年 | 182篇 |
2020年 | 109篇 |
2019年 | 185篇 |
2018年 | 253篇 |
2017年 | 169篇 |
2016年 | 176篇 |
2015年 | 260篇 |
2014年 | 288篇 |
2013年 | 387篇 |
2012年 | 572篇 |
2011年 | 564篇 |
2010年 | 308篇 |
2009年 | 303篇 |
2008年 | 487篇 |
2007年 | 491篇 |
2006年 | 572篇 |
2005年 | 522篇 |
2004年 | 447篇 |
2003年 | 423篇 |
2002年 | 373篇 |
2001年 | 197篇 |
2000年 | 223篇 |
1999年 | 187篇 |
1998年 | 97篇 |
1997年 | 68篇 |
1996年 | 80篇 |
1995年 | 52篇 |
1994年 | 53篇 |
1993年 | 47篇 |
1992年 | 117篇 |
1991年 | 112篇 |
1990年 | 91篇 |
1989年 | 96篇 |
1988年 | 68篇 |
1987年 | 97篇 |
1986年 | 79篇 |
1985年 | 85篇 |
1984年 | 57篇 |
1983年 | 62篇 |
1982年 | 29篇 |
1981年 | 29篇 |
1979年 | 65篇 |
1977年 | 30篇 |
1976年 | 29篇 |
1974年 | 36篇 |
1973年 | 38篇 |
1971年 | 36篇 |
1970年 | 27篇 |
排序方式: 共有9594条查询结果,搜索用时 0 毫秒
101.
Kimberly A Bertrand Rulla M Tamimi Christopher G Scott Matthew R Jensen V Shane Pankratz Daniel Visscher Aaron Norman Fergus Couch John Shepherd Bo Fan Yunn-Yi Chen Lin Ma Andrew H Beck Steven R Cummings Karla Kerlikowske Celine M Vachon 《Breast cancer research : BCR》2013,15(6):R104
Introduction
Understanding whether mammographic density (MD) is associated with all breast tumor subtypes and whether the strength of association varies by age is important for utilizing MD in risk models.Methods
Data were pooled from six studies including 3414 women with breast cancer and 7199 without who underwent screening mammography. Percent MD was assessed from digitized film-screen mammograms using a computer-assisted threshold technique. We used polytomous logistic regression to calculate breast cancer odds according to tumor type, histopathological characteristics, and receptor (estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor (HER2)) status by age (<55, 55–64, and ≥65 years).Results
MD was positively associated with risk of invasive tumors across all ages, with a two-fold increased risk for high (>51%) versus average density (11-25%). Women ages <55 years with high MD had stronger increased risk of ductal carcinoma in situ (DCIS) compared to women ages 55–64 and ≥65 years (Page-interaction = 0.02). Among all ages, MD had a stronger association with large (>2.1 cm) versus small tumors and positive versus negative lymph node status (P’s < 0.01). For women ages <55 years, there was a stronger association of MD with ER-negative breast cancer than ER-positive tumors compared to women ages 55–64 and ≥65 years (Page-interaction = 0.04). MD was positively associated with both HER2-negative and HER2-positive tumors within each age group.Conclusion
MD is strongly associated with all breast cancer subtypes, but particularly tumors of large size and positive lymph nodes across all ages, and ER-negative status among women ages <55 years, suggesting high MD may play an important role in tumor aggressiveness, especially in younger women. 相似文献102.
Vasa previa is a rare condition, frequently lethal, in which fetal blood vessels coming from the placenta or the umbilical cord cross the entrance of the childbirth channel before presentation. The abnormal blood vessels are result of a velamentous cord insertion or a placental alteration. It happens in 1:3000 births, with a high perinatal mortality. A 16 years-old primigest patient, at 34.6 week of gestation, was admitted to the labor, which has a good evolution, without any complication. A male new born was obtained without hearth rate or vitality, Apgar scale 0-0, weight 2800 grams, who presented an umbilical cord rupture 3 centimeters from its abdominal insertion, no where the fetal blood vessels are unprotected. It is necessary an adequate prenatal care, diagnosis and accurate management, to avoid the mortality by this rare clinical entity. 相似文献
103.
Chronic splenomegaly in Nairobi, Kenya. II. Portal hypertension 总被引:1,自引:0,他引:1
K M De Cock S Awadh R S Raja B M Wankya R A Jupp B Slavin T K Arap Siongok P H Rees J Bertrand S B Lucas 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1987,81(1):107-110
Eighty-five patients with chronic splenomegaly and proven oesophageal varices were studied at Kenyatta National Hospital, Nairobi. The major defined groups were hepatosplenic schistosomiasis (24%), cirrhosis (20%) and portal vein occlusion (11%). Hyper-reactive malarial splenomegaly (tropical splenomegaly syndrome) was considered as the cause of oesophageal varices in only one patient. In 26% of cases liver biopsy was non-diagnostic and the extrahepatic portal vein was demonstrated radiologically to be patent. Such patients were thought to be suffering from idiopathic portal hypertension, not previously described elsewhere in Africa. Hepatitis B surface antigen was detected in 12% of controls and in 58% of patients with cirrhosis (p less than 0.001). Some serological marker of previous hepatitis B virus infection was present in 92% of patients with cirrhosis and in 79% of controls. Kamba patients from Machakos and Kitui Districts were significantly more prevalent than expected among these 85 cases of portal hypertension. 相似文献
104.
OBJECTIVE: The purpose of this study was to determine whether global statistical data from radionuclide ventilation-perfusion scans could predict the likelihood of pulmonary embolism. MATERIALS AND METHODS: Digital data were obtained from 161 patients undergoing both radionuclide ventilation-perfusion scanning and subsequent pulmonary angiography. Morphometric data characterizing whole-lung perfusion and ventilation parameters were input into artificial neural networks in an attempt to predict the likelihood of pulmonary embolism. RESULTS: The performance of artificial neural networks using only automated global region of interest-based data was superior to that of clinicians in predicting the likelihood of acute pulmonary embolism in patients with normal findings on chest radiographs with segmental or larger emboli (p < .005) and in patients with normal findings on chest radiographs and emboli of any size (p < .01). Network performance did not significantly differ from clinician performance in patients with abnormal findings on chest radiographs. CONCLUSION: The adjunctive use of artificial neural networks using only user-independent, standard image statistics can significantly improve accuracy in the diagnosis of pulmonary embolism in patients with normal findings on chest radiographs. 相似文献
105.
Florent Le Bars Remy Pascot Charles Ricordel Herve Corbineau Jean Philippe Verhoye Bertrand Richard De Latour Simon Rouze 《中华创伤杂志(英文版)》2020,23(3):185-186
Thoracic splenosis is the autotransplantation of splenic tissue in the left thoracic cavity as a result of a splenic injury. This rare pathology is usually asymptomatic and may be discovered on incidental imaging, but the diagnosis often requires invasive procedures such as surgery in order to eliminate a neoplasic origin. We report a rare symptomatic case of a 39-year-old man presenting with chest pain and multiple nodules revealed on a computed tomography scan. The patient underwent a surgical exploration and the pathological studies concluded to a thoracic splenosis. Indeed, the previous medical history of the patient revealed a left thoraco-abdominal traumatism during childhood. The aim of this paper is to emphasize
that the diagnosis can now be performed using only imaging techniques such as technetium-99 sulfur colloid or labelled heat-denatured red blood cell scintigraphy to avoid unnecessary invasive procedures including thoracotomy. 相似文献
106.
Christian Jenssen Maria Victoria Alvarez-S��nchez Bertrand Napol��on Siegbert Faiss 《World journal of gastroenterology : WJG》2012,18(34):4659-4676
Endoscopic ultrasonography (EUS) has gained wide acceptance as an important, minimally invasive diagnostic tool in gastroenterology, pulmonology, visceral surgery and oncology. This review focuses on data regarding risks and complications of non-interventional diagnostic EUS and EUS-guided fine-needle biopsy (EUS-FNB). Measures to improve the safety of EUS und EUS-FNB will be discussed. Due to the specific mechanical properties of echoendoscopes in EUS, there is a low but noteworthy risk of perforation. To minimize this risk, endoscopists should be familiar with the specific features of their equipment and their patients’ specific anatomical situations (e.g., tumor stenosis, diverticula). Most diagnostic EUS complications occur during EUS-FNB. Pain, acute pancreatitis, infection and bleeding are the primary adverse effects, occurring in 1% to 2% of patients. Only a few cases of needle tract seeding and peritoneal dissemination have been reported. The mortality associated with EUS and EUS-FNB is 0.02%. The risks associated with EUS-FNB are affected by endoscopist experience and target lesion. EUS-FNB of cystic lesions is associated with an increased risk of infection and hemorrhage. Peri-interventional antibiotics are recommended to prevent cyst infection. Adequate education and training, as well consideration of contraindications, are essential to minimize the risks of EUS and EUS-FNB. Restricting EUS-FNB only to patients in whom the cytopathological results may be expected to change the course of management is the best way of reducing the number of complications. 相似文献
107.
108.
109.
110.
Hong Chee Chew Arjun Iyer Mark Connellan Sarah Scheuer Jeanette Villanueva Ling Gao Mark Hicks Michelle Harkness Claudio Soto Andrew Dinale Priya Nair Alasdair Watson Emily Granger Paul Jansz Kavitha Muthiah Andrew Jabbour Eugene Kotlyar Anne Keogh Kumud Dhital 《Journal of the American College of Cardiology》2019,73(12):1447-1459