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   1346496篇
  免费   94546篇
  国内免费   2960篇
耳鼻咽喉   19872篇
儿科学   40392篇
妇产科学   38828篇
基础医学   188624篇
口腔科学   41144篇
临床医学   113409篇
内科学   264320篇
皮肤病学   30453篇
神经病学   107153篇
特种医学   53915篇
外国民族医学   435篇
外科学   209193篇
综合类   31084篇
现状与发展   6篇
一般理论   439篇
预防医学   93333篇
眼科学   31530篇
药学   100844篇
  4篇
中国医学   3101篇
肿瘤学   75923篇
  2018年   12161篇
  2016年   10877篇
  2015年   12225篇
  2014年   17183篇
  2013年   25851篇
  2012年   33878篇
  2011年   35755篇
  2010年   21249篇
  2009年   20603篇
  2008年   34131篇
  2007年   37267篇
  2006年   37740篇
  2005年   36451篇
  2004年   35458篇
  2003年   34368篇
  2002年   33869篇
  2001年   63811篇
  2000年   65484篇
  1999年   55503篇
  1998年   14707篇
  1997年   13495篇
  1996年   12965篇
  1995年   12246篇
  1994年   11485篇
  1992年   42806篇
  1991年   41354篇
  1990年   40611篇
  1989年   39609篇
  1988年   37022篇
  1987年   36459篇
  1986年   34929篇
  1985年   33129篇
  1984年   24848篇
  1983年   21072篇
  1982年   12681篇
  1981年   11588篇
  1979年   23949篇
  1978年   17084篇
  1977年   14848篇
  1976年   13395篇
  1975年   15281篇
  1974年   18105篇
  1973年   17571篇
  1972年   16814篇
  1971年   15732篇
  1970年   14921篇
  1969年   14358篇
  1968年   13468篇
  1967年   12025篇
  1966年   11269篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Type 1 diabetes is one of the commonest chronic disorders encountered in children and adolescents. When it first becomes apparent in children, approximately 20% of them have clinical and biochemical signs of ketoacidosis (DKA). In the presence of unusual clinical symptoms it is necessary to consider the possibility of associated conditions, such as coeliac disease, immunothyroiditis and Addison’s disease. Children with diabetes must be treated by a multidisciplinary team made up of paediatrician, paediatric diabetes specialist, psychologist, social worker, ophthalmologist, dietitian, nurse and diabetes counsellor, making it essential for them to be treated in regional specialised centres. They are treated in their own psychosocial environment and their families are involved in the therapy. Comprehensive, multidisciplinary treatment strategies have now made it possible for these patients to enjoy normal physical wellbeing and near-normal psychosocial development. Prevention and early treatment of of disturbances associated with diabetes remain an important concern. The fact that type 2 diabetes must now be looked for in overweight children and adolescents is a new aspect of diabetes medicine.  相似文献   
104.
According to the current nutritional recommendations issued by professional diabetes and nutrition associations, diabetic patients should keep to a diet consisting of 45–60% carbohydrates, 10–20% protein, and not more than 35% fat. However, not all of these nutritional recommendations are evidence based. For example, current studies show that the intake of insoluble roughage may be underrepresented. It is also possible that diabetic patients could benefit from keeping to the lower end of the recommended range for carbohydrates (45%) and the upper end of the range advised for protein (20%).  相似文献   
105.
It is often difficult for medical professionals to understand the behaviour of people with diabetic foot syndrome. We describe the different psychological factors that play a role in the maintenance of intermittent implementation of medical recommendations. In particular we look at the consequences of neuropathy and of the recommendation to offload pressure, as well as the contradictions between the realities of the patient and the medical professionals involved in their care. We show that the solutions that patients develop are based on normal psychological processes and we encourage professionals to consider these aspects in their relationship to people with DFS and when developing individualised preventative measures.  相似文献   
106.
SPECT with 99mTc-labeled agents is better able to detect viability after nitrate administration. Nitrates induce vasodilation and may increase blood flow to severely hypoperfused but viable myocardium, thereby enhancing tracer delivery and improving the detection of viability. Quantitative data on the changes in blood flow are lacking in SPECT but can be provided by PET. The aim of the present study was to use PET to evaluate whether nitrate administration increases blood flow to chronically dysfunctional but viable myocardium. METHODS: 13N-Ammonia PET was used to quantitatively assess blood flow, and 18F-FDG PET was used as the gold standard to detect viable myocardium. Twenty-five patients with chronic ischemic left ventricular dysfunction underwent 13N-ammonia PET at rest and after nitrate administration. RESULTS: A significant increase in nitrate-enhanced blood flow was observed in viable segments (from 0.55 +/- 0.15 to 0.68 +/- 0.24 mL/min/g, P < 0.05). No statistically significant change in blood flow was observed in nonviable segments (0.60 +/- 0.20 vs. 0.55 +/- 0.18 mL/min/g). A ratio of at least 1.1 for nitrate-enhanced flow to resting flow allowed optimal detection of viable myocardium, yielding a sensitivity of 82% with a specificity of 100%. CONCLUSION: 13N-Ammonia PET showed a significant increase in nitrate-enhanced blood flow in viable myocardium, whereas blood flow remained unchanged after nitrate administration in nonviable myocardium. Nitrate use during myocardial perfusion imaging will lead to improved assessment of myocardial viability.  相似文献   
107.
108.
109.
Summary We present a case of blindness and Anton’s syndrome in a psychiatric patient with late diagnosis of a giant frontal meningioma. The criteria for advanced diagnostic imaging in the psychiatric population are discussed. We conclude that MR or CT scan is indicated in psychiatric in-patients who fail to improve with standard psychiatric treatment. This strategy should be submitted to a cost-benefit analysis.  相似文献   
110.
BACKGROUND: The laparoscopic resection of rectal cancer shows morbidity and oncological safety comparable to the open approach, but morbidity increases after conversion to open resection. No oncological long-term results are available for the latter patients. METHODS: From 01/01/2000-31/12/2002, patients with curatively resected rectal cancer enrolled in a observational study were evaluated for morbidity, mortality, tumor- and local recurrence rate, paying attention to patients with conversion from laparoscopic to open resection. RESULTS: 237 (3.3%) of 7,189 patients underwent laparoscopic resection (ITT). These patients showed significantly more T1/2 tumors (P<0.001) in earlier UICC stages (P<0.001) than open resected patients. 35 (14.8%) of 237 laparoscopic procedures were converted. Compared with patients receiving complete laparoscopic or open resection, these patients showed significantly higher frequencies of intraoperative (P<0.001) and general postoperative complications (P=0.003) as well as the highest overall morbidity (P=0.031). After a median follow-up of 30.1 months, the highest 5-year local recurrence rate was found in the converted group (16.0%). The laparoscopically resected patients showed a local recurrence rate of 3.3%, patients with open resection of 12.4% (P=0.082). The disease-free survival rate did not differ between the groups (P=0.585). CONCLUSION: Laparoscopic resection of rectal cancer provides oncological results similar to open resection. After conversion, the short and oncological long-term outcomes were worse. Considering a conversion rate of 15%, only a strict indication for the laparoscopic approach can be allowed, and laparoscopic resection should be performed at centers.  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