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   265941篇
  免费   39767篇
  国内免费   1683篇
耳鼻咽喉   4354篇
儿科学   6793篇
妇产科学   5116篇
基础医学   24821篇
口腔科学   8499篇
临床医学   42229篇
内科学   59791篇
皮肤病学   6816篇
神经病学   27385篇
特种医学   10851篇
外国民族医学   14篇
外科学   44340篇
综合类   2259篇
现状与发展   41篇
一般理论   127篇
预防医学   25961篇
眼科学   5792篇
药学   12034篇
中国医学   264篇
肿瘤学   19904篇
  2024年   812篇
  2023年   5789篇
  2022年   2650篇
  2021年   6217篇
  2020年   7341篇
  2019年   5289篇
  2018年   10542篇
  2017年   10065篇
  2016年   11030篇
  2015年   11608篇
  2014年   15559篇
  2013年   19172篇
  2012年   14839篇
  2011年   15325篇
  2010年   13362篇
  2009年   15235篇
  2008年   13890篇
  2007年   13405篇
  2006年   14405篇
  2005年   13056篇
  2004年   11645篇
  2003年   10527篇
  2002年   9980篇
  2001年   4028篇
  2000年   3028篇
  1999年   3884篇
  1998年   4106篇
  1997年   3505篇
  1996年   3319篇
  1995年   2984篇
  1994年   2263篇
  1993年   1975篇
  1992年   2076篇
  1991年   1848篇
  1990年   1565篇
  1989年   1515篇
  1988年   1438篇
  1987年   1304篇
  1986年   1278篇
  1985年   1203篇
  1984年   1247篇
  1983年   1131篇
  1982年   1252篇
  1981年   1137篇
  1980年   908篇
  1979年   770篇
  1978年   806篇
  1977年   700篇
  1976年   628篇
  1974年   606篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The action of papain and bromelain, prepared over a pH range from 4.6 to 8.6, was evaluated for the ability to render red cells agglutinable by five incomplete antibodies of differing blood group specificities using a two-stage technique. The optimal pH for treatment of red cells by activated papain or bromelain was between 5.4 and 5.8. Above this pH range, a fall in serological sensitivity was apparent which was much more pronounced with papain than with bromelain. The optimal pH for enzyme treatment of red cells can be achieved in two-stage techniques, but not in one-stage techniques due to the buffering effect of serum proteins.  相似文献   
102.
103.
This study evaluates the potential for endothelial seeding of a collagen-impregnated Dacron graft with or without surface modifiers (fibronectin, heparin) to attach and retain these cells during flow. Human umbilical endothelial cells were harvested, cultured, labeled with Indium111-oxine and seeded onto 30 mm X 4 mm diameter grafts. Six graft surfaces were studied: 1) a collagen-impregnated Dacron graft, HemashieldR (C); 2) C + fibronectin (C + F); 3) C + heparin (C + H); 4) C + F + H; 5) HytrelR + F (Hyt + F); and 6) Hyt + F + H. Radioactive loss determined the percentage attachment and then percentage retention of labeled inoculum after a one-hour in vitro perfusion. Scanning electron and light microscopy demonstrated the endothelium on the graft surface following perfusion. Fibronectin-coated grafts had a significantly higher percentage attachment than those without fibronectin (ANOVA, P less than 0.05). However, the percentage retention following perfusion was similar for all Dacron grafts and statistically inferior to the HytrelR grafts studied (ANOVA, P less than 0.05). SEM evaluation of the C + F + H graft surface was qualitatively the most impressive Dacron surface for seeding, yet was inferior to the HytrelR graft. We conclude that fibronectin benefits the initial attachment of endothelium to collagen-coated Dacron rivaling the HytrelR surface. Fibronectin does not improve percentage retention of the HemashieldR surface during perfusion, therefore, some of its initial benefit is lost.  相似文献   
104.
PURPOSE: Chart notes are used to support billing codes under the evaluation and management guidelines of the Health Care Financing Administration (HCFA), in addition to serving as a record of the visit. To better understand the effect of the HCFA documentation guidelines, the authors collected data on how the guidelines affect participation by university- and community-based faculty in clinical education programs. METHOD: In 2000, the authors sent six copies of their questionnaire to the associate deans of the 125 U.S. medical schools and requested they distribute them to all core clerkship directors. The questionnaire consisted of multiple-choice and short-answer questions regarding documentation of medical visits, participation of community-based faculty, understanding of HCFA documentation guidelines, and effects on education programs. RESULTS: The response rate was about 50%. Most of the 379 clerkship directors who responded (77%) stated they were aware the HCFA documentation guidelines include specifications regarding the role medical students can play and documentation of medical visits, and 64% indicated they were concerned the guidelines would affect their educational programs. Concerns included the loss of student independence and active participation in the patient care environment (37), time constraints and the changing balance between education and service (16), loss of faculty and decreased morale (11), and decreased quality of care for patients (7). CONCLUSION: Leaders of medical education must work to modify these guidelines to protect the quality of patients' care, while maximizing students' educational opportunity and participation.  相似文献   
105.
The treatment of deep cartilage defects in load-bearing joints is a problem that still has no satisfactory solution. Full-thickness defects of the articular cartilage rarely heal spontaneously, usually leaving damage that can lead to early arthrosis. Techniques currently available for the treatment of chondral defects include abrasion, drilling, micro-fracturing, transplantation of tissue autografts and allografts, and cell transplantation. Osteochondral autograft transplantation is currently the only surgical cartilage repair technique known to lead to the formation of genuine hyaline articular cartilage and its retention at least in the medium term. The Draenert method, in which a water-cooled diamond bone-cutting system is used, is an effective procedure for resurfacing the joints affected by localised cartilaginous defects, even when there is also severe bone loss. Donor-side morbidity can be kept to a minimum by filling the defect caused by harvesting with a press-fit cylinder of cancellous bone covered with periosteum for protection.  相似文献   
106.
107.
108.
Directors of nursing at 23 nursing homes with Alzheimer's units in Southwestern Pennsylvania completed a self‐reported survey of 12 questions. Responses from the self‐administered questionnaires (100% response rate) revealed a wide variation in the staff categories assessing the oral health status of newly admitted residents with AD. The respondents described oral examinations that were incomplete when compared to the oral indicators listed in the Minimum Data Set. All nursing homes reported that oral hygiene was provided each day. The number of residents in a facility had a significant effect on the frequency of oral hygiene provided. Only 52% of the facilities reported yearly oral examinations for this population. According to the respondents, dental treatment was typically performed on‐site. The oral health care costs were paid by Medicare, Medicaid, the residents/family members, or by other undescribed resources. Insufficient time, staff, and training, as well as uncooperative behavior, were identified as barriers to optimum oral health care for residents with AD. Additional staff, specialized training, and increased government reimbursement were suggested to improve the oral health care for this group of older adults. For future studies, review of medical records and on‐site evaluation of the oral health care at these facilities should be required to verify the reported practices.  相似文献   
109.
110.
The literature suggests that pain in the elderly, especially among seniors with dementia, is under-assessed and under-treated.This qualitative study solicited the perspectives of seniors, front-line nursing staff, nursing-home administrators, and informal caregivers of seniors with dementia on the current status of pain assessment and management. The views of these participants complement the research findings reported in the literature. While some of their explanations and potential solutions concerning under-treatment of pain in seniors echo views that have been presented in the literature, the participants also pointed to factors and avenues that have been given less formal consideration (e.g., systemic barriers to effective assessment and treatment of pain).They also highlighted the need for pain-control strategies beyond medication. The implications of these findings are discussed.  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