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   1381篇
  免费   78篇
  国内免费   59篇
耳鼻咽喉   6篇
儿科学   63篇
妇产科学   7篇
基础医学   88篇
口腔科学   32篇
临床医学   166篇
内科学   393篇
皮肤病学   21篇
神经病学   81篇
特种医学   265篇
外科学   137篇
综合类   41篇
预防医学   97篇
眼科学   9篇
药学   69篇
中国医学   2篇
肿瘤学   41篇
  2021年   22篇
  2019年   9篇
  2018年   20篇
  2016年   13篇
  2015年   21篇
  2014年   27篇
  2013年   42篇
  2012年   34篇
  2011年   44篇
  2010年   41篇
  2009年   33篇
  2008年   33篇
  2007年   72篇
  2006年   33篇
  2005年   34篇
  2004年   40篇
  2003年   37篇
  2002年   30篇
  2001年   24篇
  2000年   28篇
  1999年   25篇
  1998年   59篇
  1997年   36篇
  1996年   63篇
  1995年   47篇
  1994年   41篇
  1993年   50篇
  1992年   12篇
  1991年   20篇
  1990年   27篇
  1989年   34篇
  1988年   41篇
  1987年   49篇
  1986年   34篇
  1985年   36篇
  1984年   23篇
  1983年   18篇
  1982年   13篇
  1981年   27篇
  1980年   21篇
  1979年   12篇
  1978年   14篇
  1977年   16篇
  1976年   15篇
  1975年   23篇
  1974年   12篇
  1973年   16篇
  1972年   15篇
  1971年   10篇
  1970年   11篇
排序方式: 共有1518条查询结果,搜索用时 15 毫秒
81.
82.
83.
In a 38-year-old woman, the entire muscle belly of the peroneus longus was replaced by a ganglion. Signs of peroneal nerve dysfunction resulted from direct pressure of the ganglion. Excision of the ganglion required a tenodesis of the peroneus longus tendon to provide a normal gait pattern which was maintained during a 17 month follow-up period. This entity needs careful, prompt evaluation to avoid neurological damage and to distinguish it from compartment syndrome.  相似文献   
84.
Two patients had colonic perforation as a result of percutaneous nephrostomy placement followed by track dilatation and renal calculus removal. We present the technical aspects of nephrostomy placement and stone removal, as well as the clinical diagnosis and management of these cases. Both patients recovered well with conservative therapy and required no surgical intervention. This report reviews the anatomic considerations for percutaneous nephrostomy in patients undergoing renal stone removal.  相似文献   
85.
OBJECTIVE: Sparing the aortic valve has become a surgical option for patients who require repair of aortic root ectasia and have normal valve leaflets. Surgical approaches to valve sparing differ with regard to preservation of the native sinuses of Valsalva. The role of the sinuses and the importance of maintaining them remain controversial. METHODS: By using a time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging technique, aortic root and aortic blood velocity data were acquired from 2 patients with Marfan syndrome 6 months after aortic valve-sparing surgery with straight Dacron grafts and contrasted with data from 6 normal volunteers. RESULTS: In normal aortas vortical blood flow became apparent in the individual sinuses after peak systole. The vortices filled the available space behind the valve leaflets and persisted until diastole, expanding and moving inward during aortic valve closure. In contrast, no vortices were observed in the postoperative patients with Marfan syndrome with negligible sinuses. CONCLUSIONS: Changes in supravalvular flow accompany loss of sinus architecture. Whether the presence, size, and velocity of supravalvular vortices affects the function or durability of the preserved aortic valve remains to be studied.  相似文献   
86.
Foex  P; Sear  JW 《CEACCP》2004,4(3):71-75
Arterial hypertension is a major cause of morbidity and mortalitybecause of its association with coronary heart disease, cerebrovasculardisease and renal disease. The extent of target organ involvement(i.e. heart, brain and kidneys) determines outcome. North Americanstudies have shown that hypertension is a major contributorto 500 000 strokes (250 000 deaths) and 1 000 000 myocardialinfarctions (500 000 deaths) per annum.  相似文献   
87.
In recent years there has been an increasing focus in environmental risk assessment on children as a potentially susceptible population. There also has been growing recognition of the need for a systematic approach for organizing, evaluating, and incorporating the available data on children's susceptibilities in risk assessments. In this article we present a conceptual framework for assessing risks to children from environmental exposures. The proposed framework builds on the problem formulation-->analysis-->risk characterization paradigm, identifying at each phase the questions and issues of particular importance for characterizing risks to the developing organism (from conception through organ maturation). The framework is presented and discussed from the complementary perspectives of toxicokinetics and toxicodynamics.  相似文献   
88.
OBJECTIVE: The ethics of involving decisionally incapable adults in research will continue to grow in importance as more research is conducted to address the problems of decisionally impaired persons, especially elderly persons. The authors provide an updated discussion, critique, and recommendations regarding the need for clear legal and regulatory policy on this issue. METHOD: The authors summarize and build on discussions of a workshop on proxy and surrogate consent in geriatric neuropsychiatric research sponsored by the Aging Research Consortium of the National Institute of Mental Health. They incorporate the views of various stakeholders present at the workshop as well as review recent federal and state initiatives, recent empirical research and media reports, and various commission reports and relevant regulations. RESULTS: Despite a wave of initiatives in the late 1990s to clarify policy, surrogate consent for research continues to be a murky legal area and incapable subjects in the United States still lack clear regulatory protection. There is evidence that conservative risk management strategies by institutional review boards and their institutions may severely restrict research with decisionally impaired subjects. A passive approach to this problem may no longer be feasible. A recent federal advisory report on human research protections and legislative initiatives in some states could begin to provide a blueprint for future policy making. Interim recommendations for various stakeholders are given. CONCLUSIONS: It is imperative that the scientific community, patients and their advocates, and policy makers at all levels establish a constructive dialogue to clarify ethical and legal standards in the area of proxy and surrogate consent for research.  相似文献   
89.
Renal artery stenosis (RAS) is most commonly due to either fibromuscular dysplasia or atherosclerosis. The former predominates in young women while atherosclerosis is usually encountered in individuals over the age of 55. The most common clinical manifestation of fibromuscular dysplasia is hypertension, which can frequently be cured or significantly improved with percutaneous balloon dilation. Atherosclerotic RAS may present with hypertension, renal failure (ischemic nephropathy), recurrent episodes of congestive heart failure and flash pulmonary edema or may be discovered incidentally during an imaging procedure for some other reason. Screening tests for RAS have improved considerably over the last decade. While captopril renography was utilized almost exclusively in the past, duplex ultrasound of the renal arteries or magnetic resonance angiography have replaced other modalities as the screening test of choice in many centers. Rarely does an arteriogram have to be performed for diagnostic purposes only. Management of RAS consists of three possible strategies: medical management, surgical management or percutaneous therapy with balloon angioplasty and stent implantation. The treatment of choice to control hypertension in patients with fibromuscular disease is percutaneous angioplasty. Renal artery stenting has replaced surgical revascularization for most patients with atherosclerotic disease who meet the criteria for intervention.  相似文献   
90.
BACKGROUND: Several studies have shown that malnutrition is common among nursing home residents. AIM: We hypothesized that addition of natural energy-dense ingredients to a standard diet would improve voluntary energy intake and ability to perform activities of daily living (ADL) and decrease infections in elderly residents under nursing home care. METHODS: Thirty-five residents in a municipality nursing home (median age 83 years) were served either a standard diet (1600 kcal/day) (control group, n=18) or the same meals fortified with natural energy-dense ingredients (2100 kcal/day) (experimental group, n=17). Energy intake and ADL function were measured before and after the intervention. All episodes of infection were registered. Non-parametric statistics were used. RESULTS: Energy intake increased in the experimental group from 23.5 (21.3-28.5) kcal/kg/body weight before, to 31.9 (29.7-33.7) kcal/kg/body weight during the intervention (P<0.001). There was no change in energy intake in the control group. ADL function in the experimental group was unchanged, while it decreased significantly in the control group (P<0.001). The number of infections tended to be lower in the experimental group than in the control group (5 vs 13). The cost for the energy-dense ingredients was approx. 0.11 EUR per resident and day. CONCLUSIONS:Addition of natural energy-dense ingredients to regular meals is an inexpensive way to improve voluntary energy intake in elderly nursing home residents, a treatment that was accompanied by maintained ADL function.  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