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   7700篇
  免费   669篇
  国内免费   22篇
耳鼻咽喉   79篇
儿科学   222篇
妇产科学   240篇
基础医学   1066篇
口腔科学   97篇
临床医学   981篇
内科学   1553篇
皮肤病学   153篇
神经病学   801篇
特种医学   217篇
外科学   1087篇
综合类   197篇
一般理论   6篇
预防医学   818篇
眼科学   83篇
药学   367篇
中国医学   4篇
肿瘤学   420篇
  2023年   75篇
  2022年   105篇
  2021年   246篇
  2020年   142篇
  2019年   242篇
  2018年   247篇
  2017年   164篇
  2016年   194篇
  2015年   202篇
  2014年   315篇
  2013年   363篇
  2012年   511篇
  2011年   514篇
  2010年   280篇
  2009年   277篇
  2008年   383篇
  2007年   421篇
  2006年   428篇
  2005年   378篇
  2004年   333篇
  2003年   280篇
  2002年   318篇
  2001年   169篇
  2000年   178篇
  1999年   139篇
  1998年   76篇
  1997年   75篇
  1996年   46篇
  1995年   54篇
  1994年   61篇
  1993年   47篇
  1992年   111篇
  1991年   94篇
  1990年   71篇
  1989年   92篇
  1988年   78篇
  1987年   73篇
  1986年   52篇
  1985年   61篇
  1984年   45篇
  1983年   44篇
  1982年   30篇
  1981年   28篇
  1980年   36篇
  1979年   41篇
  1978年   29篇
  1977年   24篇
  1974年   21篇
  1973年   22篇
  1971年   21篇
排序方式: 共有8391条查询结果,搜索用时 15 毫秒
91.
To test the validity of a new computerized task to assess children's receptive vocabulary, event-related potentials (ERPs) were recorded from 56 typically developing children ranging in age from 5 to 12 years. This ERP-computerized vocabulary task does not require a child to give a verbal or motor (i.e. pointing) response. Single pictures, from an existing standardized test of receptive vocabulary, were presented on a computer screen and simultaneously named either correctly (congruent) or incorrectly (incongruent) via a computer. As predicted, the N400 amplitude was found to be significantly higher to the incongruent picture-word pair (i.e. the child knew it was an incorrect pairing) than to the congruent picture-word pair (i.e. the child knew it was a correct pairing). This effect was found for each of the four age groups (5 to 6 years, 7 to 8 years, 9 to 10 years, 11 to 12 years). This task accurately estimated current receptive vocabulary in typically developing children. Although still in the development stage, it may eventually serve as an adjunct to a thorough neurological and neurodevelopmental assessment of some children presenting with moderate to severe cerebral palsy.  相似文献   
92.
Home care services for people with psychiatric diagnoses are increasing in popularity with consumers, providers, and insurance companies. Traditionally, home care social workers have not provided in-home clinical services because of restrictive regulations and industry culture. This article presents strategies for establishing a clinical role for social workers in a psychiatric home care program that meets Medicare, Joint Commission on Accreditation of Healthcare Organizations, and NASW standards. A discussion of skills requirements, appropriate case assignment, professional role clarifications and differentiations, and marketing strategies is presented.  相似文献   
93.
A series of studies conducted in the same region found that programmatic, community-based health and social service interventions have a positive impact on client well-being. These proactive interventions, designed to address the full range of health and social needs, were usually provided at the same–or even lower–costs as uncoordinated, illness-focused care. The results of this series suggest that across-the-board health care reduction, atleast in a system of national health insurance, will produce poorer results, at higher cost, for people with chronic conditions living in the community. Policy planners need more research that concentrates on comparisons of outcomes between and within different models of health and social service delivery. The studies should be designed to help them determine who benefits from different serviceconfigurations carried out within a range of policy environments at various costs.  相似文献   
94.
PURPOSE: To determine whether molecular genetic analysis of ocular-adnexal lymphoid tumors, combined with histopathology and tumor location, is helpful in predicting which patients will develop systemic lymphoma. METHODS: A combined retrospective and prospective study of 77 patients with ocular-adnexal lymphoid tumors was performed. The tumors were subdivided into conjunctival, orbital, and eyelid lesions, and all were studied using both routine histopathology and molecular genetic analysis. RESULTS: Most lesions (70%) were small cell lymphomas of the mucosa-associated lymphoid tissue type, and the majority of tumors (90%) contained monoclonal or oligoclonal populations of lymphocytes discovered on molecular genetic analysis. Additionally, 72% of tumors exhibiting clonality had more than one gene rearrangement. Fifty-three percent of patients developed extraocular lymphoma sometime during the course of their disease. Patients with gene rearrangements on Southern blot hybridization had a 52% incidence of nonocular disease, compared with 63% of those without rearrangements. Patients with conjunctival tumors had a 37.5% incidence of nonocular disease, those with orbital tumors had a 54% incidence, and those with eyelid tumors had a 100% incidence of nonocular lymphoma. Only two patients died as result of systemic lymphoma. CONCLUSIONS: Most ocular-adnexal lymphoid tumors are lymphomas of the mucosa-associated lymphoid tissue type. The majority of tumors exhibit gene rearrangements on molecular genetic analysis, and this technique was not helpful in predicting which patients would develop nonocular lymphoma. Tumor location did have predictive value: Conjunctival lesions had the lowest incidence of nonocular lymphoma, and lid lesions had the highest incidence. Even with disseminated disease, most patients have a favorable prognosis with treatment.  相似文献   
95.
Reforms to medical education have refocused curricula on the need to produce primary care physicians through a problem-based, student-centered, community-oriented, and integrated approach to instruction. Course evaluations, originally designed for traditional lecture-based, teacher-centered curricula, provide inadequate input from students to support curriculum planning and change and to determine appropriate mixes of educational methods. At the University of Toronto Faculty of Medicine, a unique community-centered course, called "Health, Illness and the Community," developed a student-centered course evaluation to provide adequate student input to support curriculum planning and change. A 35-item evaluation was developed to obtain data to identify student concerns, student learning styles, and preferred community agency utilization. The results suggest that student-centered course evaluation can play a role in managing and identifying key relationships in integrated and systematic courses as well as establishing a method for continual improvement.  相似文献   
96.
Our aim was to examine the feasibility of a totally laparoscopic insertion of a bifurcated aortofemoral bypass graft in a canine model and to compare the surgical results with those in control animals undergoing standard grafting and laparoscopic-assisted bypass procedures. Using a six-port approach, we exposed and cross clamped the aorta, tunneled a bifurcated Dacron graft, and performed an end-to-end aortic anastomosis while maintaining pneumoperitoneum by means of CO2. Proximal anastomoses were performed with 4/0 double-ended continuous Prolene sutures and distal anastomoses were performed through standard groin incisions. Total operating and aortic cross-clamp times were measured as was the total blood loss for each procedure. Clinical outcome was also documented. Eight female laboratory-bred hounds underwent successful totally laparoscopic aortobifemoral bypass grafting, eight underwent open grafting, and eight underwent laparoscopic-assisted bypass. Mean operating time was 193 minutes in the animals undergoing totally laparoscopic insertion vs. 156 minutes in the open group and 180 minutes in the laparoscopic-assisted group. Aortic cross-clamping time was also significantly longer at 87 minutes vs. 43 minutes (p < 0.001)=" in=" the=" totally=" laparoscopic=" group,=" but=" blood=" loss=" was=" less.=" all=" eight=" laparotomy=" and=" laparoscopic-assisted=" dogs=" were=" still=" alive=" with=" no=" complications=" at=" 28=" days,=" whereas=" three=" of=" the=" eight=" in=" the=" totally=" laparoscopic=" group=" showed=" evidence=" of=" temporary=" paraplegia.=" this=" experimental=" study=" demonstrates=" that=" a=" totally=" laparoscopic=" approach=" can=" be=" used=" to=" insert=" a=" bifurcated=" aortofemoral=" bypass=" with=" a=" proximal=" end-to-end=" anastomosis=" but=" currently=" does=" not=" save=" time=" and=" may=" increase=" the=" risk=" of=" neurologic=">Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.  相似文献   
97.
98.
Data from a trial of preoperative whole body disinfection in postoperative wound infection prophylaxis involving 3733 patients were used to analyse the cost of a postoperative wound infection. The overall wound infection rate was 14.73% (513/3482), 61% of which were diagnosed after hospital discharge (312 outpatient infections versus 201 inpatient infections). This highlights the prevalence of the transfer of the cost of wound infection to the community. The inpatient and outpatient costs were calculated separately for those with and without a wound infection. Operative procedures were placed into 38 different categories. 12 of these 38 categories accounted for over 90% of the total number of operations performed. Overall, infected patients cost society more than noninfected patients. The hospitalisation costs for inpatients for all categories of patients, whether infected or not, comprised over 99% of the total cost. The excess cost for the infected patients in the study was calculated as 312 915 British pounds sterling (1990 British pounds sterling) or 610 British pounds sterling per infected patient, equivalent to 1926 hospital days overall. For some operations (e.g. stripping varicose veins) an excess of 52 hospital days were associated with wound infection diagnosed after discharge from hospital. Wound infections in some operative categories were consistently more expensive to manage (e.g. excess cost/infected vascular patient = 1085 British pounds sterling) while other operative categories had less costly wound infections (e.g. excess cost/infected thyroid patient = 110 British pounds sterling).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
99.
100.
BACKGROUND: There are few data on the morbidity and mortality of planned elective surgery for infrarenal abdominal aortic aneurysm (AAA) as a single surgeon series. This audit is of a consecutive series of AAA operations performed by one surgeon in one district general hospital over a 13-year period. METHODS: 243 patients were operated on for AAA between 1985 and 1998. Data were collected on the majority of patients prospectively. A reliable method was devised to identify all patients. Any missing complication and mortality data were then collected retrospectively. RESULTS: 13 patients died as a result of their operation (5.3%). In patients over the age of 80 years (36), five patients died (14%) and in the 207 patients under the age of 80 years, eight died (3.8%). Cardiac deaths were the most frequent cause (38%); 82 patients had recorded complications (34%). The operative mortality rate has increased in later years, (2.2% to 7.1%), largely due to an increase in the very elderly accepted for operation (12% to 16%), and a possible increase in co-morbidity. CONCLUSIONS: An acceptable and comparable mortality rate can be achieved in a district general hospital. The complication rate is high indicating the need for very intense medical and nursing care for these patients postoperatively. There is a considerable variance in mortality rates with age and risk even in the practice of one surgeon, indicating a need to be very knowledgeable and cautious in interpreting postoperative mortality data. This is the largest single surgeon series to date in the UK.  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