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   4981998篇
  免费   377246篇
  国内免费   17595篇
耳鼻咽喉   69136篇
儿科学   160015篇
妇产科学   132722篇
基础医学   746549篇
口腔科学   137968篇
临床医学   463158篇
内科学   904684篇
皮肤病学   118080篇
神经病学   416839篇
特种医学   191972篇
外国民族医学   1065篇
外科学   738923篇
综合类   139914篇
现状与发展   24篇
一般理论   2843篇
预防医学   419260篇
眼科学   116841篇
药学   353759篇
  30篇
中国医学   13828篇
肿瘤学   249229篇
  2021年   57237篇
  2019年   59588篇
  2018年   76776篇
  2017年   58921篇
  2016年   65228篇
  2015年   77665篇
  2014年   112125篇
  2013年   178343篇
  2012年   145452篇
  2011年   153991篇
  2010年   133015篇
  2009年   132178篇
  2008年   138730篇
  2007年   148532篇
  2006年   155898篇
  2005年   149611篇
  2004年   149955篇
  2003年   139551篇
  2002年   128400篇
  2001年   194571篇
  2000年   191331篇
  1999年   172390篇
  1998年   75498篇
  1997年   70369篇
  1996年   68284篇
  1995年   63782篇
  1994年   57766篇
  1993年   53510篇
  1992年   126828篇
  1991年   121775篇
  1990年   117419篇
  1989年   113923篇
  1988年   104992篇
  1987年   102962篇
  1986年   97467篇
  1985年   94754篇
  1984年   76927篇
  1983年   67976篇
  1982年   51303篇
  1981年   47466篇
  1980年   44462篇
  1979年   67058篇
  1978年   52623篇
  1977年   46138篇
  1976年   43169篇
  1975年   43687篇
  1974年   48770篇
  1973年   46710篇
  1972年   43828篇
  1971年   40729篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
Short History of Interventional Neuroradiology What about the Future?   总被引:1,自引:0,他引:1  
1 Short historical background of interventional neuroradiology Even if a number of us were among the pioneers of Interventional Neuroradiology, this specialty has now reached its period of maturity. Schematically, the era of the pioneers began forty years ago and lasted about 15 years, between 1960 and 1975. During that period, on the initiative of Fedor Serbinenko (Russia) and Ren6 Djindjian (France), "intracerebral navigation " using small balloons, which became gradually "detachable", has been invented. At the same time, we discovered how to use these balloons to occlude intracranial vascular lesions, inaccessible or hardly accessible to traditional open skull neurosurgery, for example, carotid cavernous fistulas. Very rapidly, a lot of different embolic particles were successively tested, ranging at first from pieces of muscle, to small glass or silastic beads, gelfoam and dura mater pieces... During this period, parallel progress of hyperselective catheterization and consequently of microangiography allowed to establish new classifications of main vascular pathologies (distinction between brain arteriovenous malformations and dural fistulas ... ). These new classifications allowed a better understanding of physiopathology. This first period was thus primarily devoted to development of very precise diagnosis and techniques of hyperselective endovascular occlusion.  相似文献   
122.
BACKGROUND: Physical activity is a healthful behavior that has promise for combating feelings of low energy and fatigue. Despite evidence suggesting that fatigue is a prodromal symptom of major cardiac events, improvements in feelings of energy and fatigue have largely been ignored by reviewers of cardiac rehabilitation literature who have focused on anxiety, depression and general measures of quality of life. DESIGN: A meta-analytical review. METHODS AND RESULTS: Computer databases were searched from January 1945 to May 2005 to identify relevant literature. A total of 36 studies consisting of 4765 subjects were included. Cardiac rehabilitation exercise programs were consistently associated with increases in energy and decreases in fatigue. The magnitude of the effect was moderately large (mean delta 0.51; 95% confidence interval 0.42-0.61) but was heterogeneous and modified by features of the research design. Comparison of effect sizes in cardiac rehabilitation studies concurrently measuring energy/fatigue, anxiety and depression suggest that exercise-based cardiac rehabilitation programs have larger effects on feelings of energy and fatigue compared with anxiety and depression. CONCLUSION: This review quantifies the potential benefit of cardiac rehabilitation exercise programs on feelings of energy and fatigue, and suggests that cardiac rehabilitation researchers and practitioners may benefit from examining, and perhaps even focusing on, feelings of energy and fatigue as an important outcome variable. A greater understanding of the effect of cardiac rehabilitation exercise programs on feelings of energy and fatigue will be reached when more true experiments are conducted thereby avoiding the primary limitation of the literature reviewed; that is, the frequent use of non-experimental research designs.  相似文献   
123.
124.
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   
125.
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   
126.
Chronic transplant dysfunction is a complex dynamic pathogenic process. Clinically, a decrease in glomerular filtration rate (GFR) becomes apparent leading to chronic renal insufficiency and dialysis or death from cardiovascular events. Chronic transplant dysfunction can develop into a chronic alIograft nephropathy (CAN) as a specific entity with dynamic progression. CAN includes a collection of immunologic and non-immunologic factors, rejection, ischemia time, donor and recipient characteristics and toxicity of calcineurin inhibitors. Despite improvements in immunosuppression, the long-range prognosis of renal allografts has not improved. Whether modern immunosuppressive concepts with reduction or avoidance of calcineurin inhibitors and a therapy based on antimetabolites, such as mycophenolate or mTOR-inhibitors could lead to a prolongation of transplant survival, remains to be seen.  相似文献   
127.
BACKGROUND: Presently, complementary and alternative medicine, including both therapies and herbal/oral supplements, is used globally. Few studies have examined the use of specific therapies, separate from herbal/oral supplements, in cardiac rehabilitation. This paper presents a systematic evaluation of current research evidence related to use of specific complementary and alternative medicine therapies in secondary prevention of cardiovascular disease, with a view to making recommendations for cardiac rehabilitation. DESIGN AND METHODS: A literature search was conducted using complementary and alternative medicine websites, Medline, Allied and Complementary Medicine, CINAHL, Cochrane databases, EMBASE, SportDiscus, Clinical Evidence, and Evidence-Based Practice to locate research-based scientific evidence related to the use of complementary and alternative medicine in cardiac rehabilitation. Search keywords included heart, cardiac, cardiovascular, coronary, myocardial and rehabilitation, combined with particular therapies. Herbal/oral supplements were not included in this evaluation. RESULTS: Some complementary and alternative medicine therapies may be useful to patients by themselves or coupled with traditional cardiac rehabilitation. Tai chi, as a complement to existing exercise interventions, can be utilized for low and intermediate risk patients. transcendental meditation may be used as a stress reduction technique. There was insufficient evidence found for the use of acupuncture or chelation therapy in cardiac rehabilitation or secondary prevention. CONCLUSIONS: Some complementary and alternative medicine therapies hold promise for patients in cardiac rehabilitation. Further research is essential, however, in all areas of complementary and alternative medicine to confirm its usefulness as an adjunct to cardiac rehabilitation.  相似文献   
128.
129.
Zusammenfassung In Deutschland leiden 25% der über 70-Jährigen unter einem Diabetes mellitus. Biologisch ältere, multimorbide und in ihren Funktionen beeinträchtigte geriatrische Patienten benötigen spezielle Vorgehensweisen bei Zielplanung, Allgemeinmaßnahmen und Pharmakotherapie. Auf der Basis der vorhandenen Leitlinien werden gesicherte Erkenntnisse dargestellt und Empfehlungen zu den Besonderheiten der Therapie des geriatrischen Diabetespatienten gegeben. Besonderes Augenmerk liegt dabei auf der Interaktion von geriatrischen Syndromen und Diabetes sowie der Verbesserung der Lebensqualität.  相似文献   
130.
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   
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