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   1818168篇
  免费   129083篇
  国内免费   3890篇
耳鼻咽喉   23712篇
儿科学   59809篇
妇产科学   49081篇
基础医学   259767篇
口腔科学   52679篇
临床医学   161503篇
内科学   355089篇
皮肤病学   42227篇
神经病学   143882篇
特种医学   69007篇
外国民族医学   244篇
外科学   275381篇
综合类   39473篇
现状与发展   4篇
一般理论   567篇
预防医学   131323篇
眼科学   42973篇
药学   132272篇
  7篇
中国医学   4649篇
肿瘤学   107492篇
  2021年   13950篇
  2019年   14799篇
  2018年   22557篇
  2017年   17415篇
  2016年   19487篇
  2015年   21435篇
  2014年   28908篇
  2013年   42709篇
  2012年   59049篇
  2011年   62454篇
  2010年   36681篇
  2009年   33350篇
  2008年   58586篇
  2007年   62233篇
  2006年   62458篇
  2005年   59654篇
  2004年   57404篇
  2003年   54819篇
  2002年   53020篇
  2001年   95757篇
  2000年   98489篇
  1999年   79941篇
  1998年   21002篇
  1997年   18286篇
  1996年   18200篇
  1995年   17415篇
  1994年   15964篇
  1993年   14699篇
  1992年   58127篇
  1991年   55909篇
  1990年   53599篇
  1989年   51378篇
  1988年   46685篇
  1987年   45546篇
  1986年   42745篇
  1985年   40685篇
  1984年   29994篇
  1983年   25459篇
  1982年   14466篇
  1981年   12936篇
  1979年   26039篇
  1978年   18019篇
  1977年   15409篇
  1976年   14278篇
  1975年   14988篇
  1974年   18050篇
  1973年   17316篇
  1972年   16002篇
  1971年   14794篇
  1970年   13744篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
141.
142.
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   
143.
Background. It has been reported that gender differences in cardiovascular outcomes found in adults also are present in children who undergo surgical repair for congenital heart disease. Methods. California statewide hospital discharge data 1989–99 were used to study outcomes in children <18 years undergoing cardiac surgery. Hospital discharge data were linked to death registry data to study postdischarge death within 30 days of discharge. We used logistic regression to evaluate the effect of gender on mortality controlling for age, race and ethnicity, type of insurance, household income, date and month of surgery, type of admission, hospital case volume, and various types of procedures. Results. There were 25 402 cardiac surgery cases with 1505 in‐hospital deaths (mortality rate of 5.92%). An additional 37 deaths occurred within 30 days after hospital discharge. Crude mortality rates for males (5.99%) and females (5.84%) were not significantly different. However, fewer neonates were female and females underwent a higher proportion of low‐risk procedures than males. Logistic regression revealed that females, compared with males, had a significantly higher odds ratio (OR) for in‐hospital mortality (OR = 1.18, P < .01) and overall (up to 30 days post discharge) mortality (OR = 1.18, P < .01). The risk‐adjusted length of hospital stay was similar between females and males while charges per hospital day were slightly higher in females than males. The prevalence of Down syndrome, pulmonary hypertension, and failure to thrive were higher in females. Conclusions. Female gender is associated with an 18% higher in‐hospital and 30‐day postdischarge mortality as compared with male gender. There was no difference in length of hospital stay between males and females. The mechanism by which female gender acts as a risk factor requires further investigation.  相似文献   
144.
145.
146.
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   
147.
Genetic disorders of mineral metabolism cause urolithiasis, renal disease, and osteodystrophy. Most are rare, such that the full spectrum of clinical expression is difficult to appreciate. Diagnosis is further complicated by overlap of clinical features. Dent's disease and primary hyperoxaluria, inherited causes of calcium urolithiasis, are both associated with nephrocalcinosis and urolithiasis in early childhood and renal failure that can occur at any age but is seen more often in adulthood. Bone disease is an inconsistent feature of each. Dent's disease is caused by mutations of the CLCN-5 gene with impaired kidney-specific CLC-5 chloride channel expression in the proximal tubule, thick ascending limb of Henle, and the collecting ducts. Resulting hypercalciuria and proximal tubule dysfunction, including phosphate wasting, are primarily responsible for the clinical manifestations. Low-molecular-weight proteinuria is characteristic. Definitive diagnosis is made by DNA mutation analysis. Primary hyperoxaluria, type I, is due to mutations of the AGXT gene leading to deficient hepatic alanine–glyoxylate aminotransferase activity. Marked overproduction of oxalate by hepatic cells results in the hyperoxaluria responsible for clinical features. Definitive diagnosis is by liver biopsy with measurement of enzyme activity, with DNA mutation analysis used increasingly as mutations and their frequency are defined.

Conclusion


These disorders of calcium urolithiasis illustrate the value of molecular medicine for diagnosis and the promise it provides for innovative and more effective future treatments.  相似文献   
148.
149.
A method is presented for 3D MRI in an extended field of view (FOV) based on continuous motion of the patient table and an efficient acquisition scheme. A gradient-echo MR pulse sequence is applied with lateral (left-right (L/R)) frequency-encoding direction and slab selection along the direction of motion. Compensation for the table motion is achieved by a combination of slab tracking and data alignment in hybrid space. The method allows fast k-space coverage to be achieved, especially when a short sampling FOV is chosen along the direction of table motion, as is desirable for good image quality. The method can be incorporated into different acquisitions schemes, including segmented k-space scanning, which allows for contrast variation with the use of magnetization preparation. Head-to-toe images of volunteers were obtained with good quality using 3D spoiled gradient-echo sequences. As an example of magnetization-prepared imaging, fat/water separated images were acquired using chemical shift selective (CHESS) presaturation pulses.  相似文献   
150.
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