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   395937篇
  免费   47037篇
  国内免费   3311篇
耳鼻咽喉   7547篇
儿科学   11739篇
妇产科学   6944篇
基础医学   36512篇
口腔科学   6018篇
临床医学   50799篇
内科学   97938篇
皮肤病学   10641篇
神经病学   38384篇
特种医学   14490篇
外国民族医学   12篇
外科学   77072篇
综合类   3700篇
现状与发展   72篇
一般理论   318篇
预防医学   28027篇
眼科学   9771篇
药学   18019篇
  6篇
中国医学   391篇
肿瘤学   27885篇
  2024年   788篇
  2023年   5807篇
  2022年   3484篇
  2021年   8223篇
  2020年   8843篇
  2019年   7282篇
  2018年   12884篇
  2017年   11338篇
  2016年   12788篇
  2015年   13718篇
  2014年   23141篇
  2013年   26498篇
  2012年   23172篇
  2011年   24063篇
  2010年   20380篇
  2009年   22833篇
  2008年   22146篇
  2007年   21316篇
  2006年   23533篇
  2005年   20831篇
  2004年   19135篇
  2003年   16996篇
  2002年   16182篇
  2001年   5862篇
  2000年   4591篇
  1999年   5439篇
  1998年   6518篇
  1997年   5805篇
  1996年   5333篇
  1995年   5083篇
  1994年   3595篇
  1993年   3070篇
  1992年   2619篇
  1991年   2528篇
  1990年   2022篇
  1989年   2139篇
  1988年   1975篇
  1987年   1780篇
  1986年   1833篇
  1985年   1682篇
  1984年   1755篇
  1983年   1630篇
  1982年   1864篇
  1981年   1700篇
  1980年   1508篇
  1979年   1016篇
  1978年   1061篇
  1977年   1023篇
  1976年   823篇
  1975年   758篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
This paper reports the proceedings of the discussion panel assigned to look at clinical aspects of quality in emergency medicine. One of the seven stated objectives of the Academic Emergency Medicine consensus conference on quality in emergency medicine was to educate emergency physicians regarding quality measures and quality improvement as essential aspects of the practice of emergency medicine. Another topic of interest was a discussion of the value of information technology in facilitating quality care in the clinical practice of emergency medicine. It is important to note that this is not intended to be a comprehensive review of this extensive topic, but instead is designed to report the discussion that occurred at this session of the consensus conference.  相似文献   
72.
73.
74.
75.
Objective: The study goal was to compare the laser spot size created using reflective and refractive micromanipulators with a CO2 laser and to determine the sensitivity of spot size to laser power. Study Design and Setting: A CO2 laser and operating microscope (400-mm focal length) was coupled to either a reflective (Cassegrain-like) or refractive micromanipulator. Laser spot size was determined by measuring the region of ablation created by laser irradiation of wood (dry tongue depressors), exposed photographic film, and agar gel using optical micrometry. Laser power varied from 0.5 to 20 W with pulse durations of 0.1 and 0.5 second. Results: The reflective micromanipulator demonstrated overall smaller spot sizes for a given laser power and lower incremental change in spot size with increasing power. The reflective design demonstrated less sensitivity to increases in laser power. Conclusions: Micromanipulator optical design can result in significant differences in laser spot size. The reflective device used in this study demonstrated less sensitivity to increasing laser power. (Otolaryngol Head Neck Surg 2002;126:593-597.)  相似文献   
76.
77.
Although lesions of the pterygopalatine space are uncommon, there are instances in which this relatively inaccessible region must be entered for biopsy or excision of masses. Traditional open approaches to the pterygopalatine space, involving external or intraoral incisions, provide limited visualization and carry associated morbidities. The evolution and advancement of endoscopic sinus surgical technique in recent years has led to its application to anatomic areas outside the strict limits of the sinonasal cavities. Such minimally invasive approaches are safe, effective, and spare unnecessary discomfort to the patient. This article describes the authors' method for performing an endoscopic approach to the pterygopalatine space.  相似文献   
78.
79.
The purpose of this study was to provide, in a large number of patients, comprehensive Doppler echocardiographic assessment of normal St Jude Medical mitral valve prosthesis function using Doppler-derived hemodynamic variables, including the mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio and prosthesis performance index. The pressure half-time was less than 130 milliseconds in all patients, and all but one patient had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2. There was a significant (P < .001) negative correlation between the prosthesis performance index and prosthesis size. This negative correlation suggests that there is more efficient use of the in vitro geometric orifice area with smaller prostheses.  相似文献   
80.
OBJECTIVE: This study was designed to investigate potential areas of practice for the clinical laboratory scientist (CLS) and to propose a graduate curriculum to prepare the practitioner for an advanced level of practice. DESIGN: Meta-analysis of PharmD, physician assistant, physical therapy, and nurse practitioner curricula focusing on academic and clinical advanced practice was used to develop an educational model and curriculum for a professional doctorate in clinical laboratory science (CLS). MAIN OUTCOME MEASURE: (1) New educational model for CLS advanced practice; (2) A proposed curriculum for a Doctorate of Clinical Laboratory Science degree. RESULTS: A new curriculum model was adapted from established healthcare educational models. CONCLUSION: Although there is a need for a baccalaureate degree in CLS there is also a role for expanded education and responsibilities for CLS practitioners. The CLS Advanced Practitioner design focuses on moving students from the baccalaureate level to the doctoral level and prepares the individual to become an integral part of the healthcare team.  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