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   3284053篇
  免费   283012篇
  国内免费   14748篇
耳鼻咽喉   46093篇
儿科学   100148篇
妇产科学   83347篇
基础医学   518120篇
口腔科学   88996篇
临床医学   300095篇
内科学   575802篇
皮肤病学   90830篇
神经病学   286135篇
特种医学   131089篇
外国民族医学   210篇
外科学   521823篇
综合类   102645篇
现状与发展   92篇
一般理论   2250篇
预防医学   274168篇
眼科学   75104篇
药学   222690篇
  22篇
中国医学   9293篇
肿瘤学   152861篇
  2021年   56607篇
  2020年   37770篇
  2019年   59311篇
  2018年   74280篇
  2017年   57351篇
  2016年   63394篇
  2015年   77555篇
  2014年   114612篇
  2013年   179870篇
  2012年   92438篇
  2011年   91396篇
  2010年   120259篇
  2009年   126660篇
  2008年   77877篇
  2007年   80011篇
  2006年   91825篇
  2005年   86580篇
  2004年   87998篇
  2003年   78642篇
  2002年   68044篇
  2001年   86359篇
  2000年   78051篇
  1999年   81905篇
  1998年   65022篇
  1997年   63094篇
  1996年   60415篇
  1995年   55888篇
  1994年   49922篇
  1993年   46566篇
  1992年   58252篇
  1991年   55569篇
  1990年   52615篇
  1989年   52165篇
  1988年   48862篇
  1987年   47736篇
  1986年   45551篇
  1985年   46029篇
  1984年   43930篇
  1983年   40544篇
  1982年   40504篇
  1981年   38298篇
  1980年   36205篇
  1979年   37178篇
  1978年   33741篇
  1977年   31024篇
  1976年   28255篇
  1975年   26727篇
  1974年   27920篇
  1973年   26818篇
  1972年   25257篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Using complete denture treatment as an introduction to clinical patient care for dental students, the purposes of the Complete Denture Prosthodontics Transition Clinic at the University of Colorado School of Dentistry are to reduce the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience, and to encourage development of student self-confidence and skills. In the 2002 spring semester, faculty at the University of Colorado School of Dentistry initiated the Complete Denture Prosthodontics Transition Clinic for DS-II (second-year) dental students, as an introduction to clinical patient care. Each patient was assigned to a team of two dental students. Three Division of Prosthodontics faculty members staffed each clinic session, providing a student-to-faculty ratio of approximately 6.6:1 and a patient-to-faculty ratio of approximately 3.3:1. All DS-II students in the Class of 2004 delivered their first complete dentures no later than 8 months (average, 184 days) after the last day of the preclinical complete denture prosthodontics course. The time from the diagnostic appointment through the denture placement appointment averaged 39 days for patients treated in this program, compared with an average of 98 days or more for previous classes. The program was successful in achieving the goal of reducing the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience.  相似文献   
994.
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function.  相似文献   
995.
996.
997.
Rare kidney allograft recipients enjoy unaltered graft function years after interruption of their immunosuppressive treatment. To assess the extent to which this state of 'operational tolerance' (TOL) is specific to the graft and not the result of a global immunodeficiency, we analyzed the response of such patients following influenza vaccination. Hemagglutination inhibition titers and frequency of IFNgamma-secreting T cells were measured before 1 and 3 months after vaccination. The proportion of healthy volunteers (HV) responding to vaccine was significantly higher than that of immunosuppressed (IS) patients. Three 'TOL' patients presented a humoral response similar to that of HV, whereas the two others had a poor response, like the IS recipients. Although the small number of patients does not allow for definitive conclusions to be made, these data suggest that the status of tolerance may be heterogeneous, with some patients with a global immunodeficiency and others with an adapted response to vaccination.  相似文献   
998.
The severity of illness in transplant patients and the complexity of transplant operations results in significant postoperative morbidity and mortality. Remarkable efforts have been made by transplant physicians to study and improve organ allocation, graft and patient survival, immunosuppression and the long-term management of post-transplant complications. Less effort has been spent studying the actual transplant operation and systems of acute transplant care. The National Surgical Quality Improvement Program (NSQIP) has provided a standardized approach to quality improvement and has demonstrated significant potential for a reduction in postoperative morbidity and mortality in other surgical disciplines. Medical centers are under increasing pressure to measure surgical quality and the nexus of transplant surgical quality improvement should not lie in the hands of CMS or JACHO, but rather it should be created and developed within the transplant community. The time has come for a national transplant surgical quality improvement program based on the NSQIP infrastructure. Such a proactive approach toward quality improvement from the transplant community is an excellent investment for patients, providers and health care payers.  相似文献   
999.
1000.
Renal ultrasonography has become the standard imaging modality in the investigation of kidneys because it displays excellent anatomic detail, requires no special preparation of the patient and does not expose the patient to radiation or contrast agents. Ultrasonography is used to determine the site and size of the kidney and to detect focal lesions like tumors, cysts and renal stones. Furthermore the presence and urodynamic relevance of hydronephrosis can reliably be revealed. Also renoparenchymatous diseases are discernible to the experienced investigator, however most glomerular diseases cannot be further subclassified. Exceptions are primarily renovascular disorders like hypertensive nephrosclerosis, diabetic nephropathy or renal vasculitis. Color Doppler sonography allows the detection and quantification of renal artery stenosis, increased resistance index values may indicate irreversible disease. Ultrasonography has also been found of value in the evaluation of renal transplant kidneys. Especially in the early transplant course potentially fatal but reversible diseases like renal vein thrombosis or urinomas are detected with high sensitivity. In the long term, an increased resistance index value may also predict allograft failure.  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