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   25773篇
  免费   5963篇
  国内免费   155篇
耳鼻咽喉   745篇
儿科学   738篇
妇产科学   805篇
基础医学   1000篇
口腔科学   2795篇
临床医学   4567篇
内科学   5936篇
皮肤病学   502篇
神经病学   2054篇
特种医学   1107篇
外国民族医学   3篇
外科学   4534篇
综合类   151篇
现状与发展   12篇
一般理论   4篇
预防医学   2971篇
眼科学   439篇
药学   587篇
中国医学   56篇
肿瘤学   2885篇
  2024年   168篇
  2023年   1140篇
  2022年   486篇
  2021年   841篇
  2020年   1341篇
  2019年   650篇
  2018年   1546篇
  2017年   1420篇
  2016年   1650篇
  2015年   1724篇
  2014年   2187篇
  2013年   2629篇
  2012年   1232篇
  2011年   1137篇
  2010年   1563篇
  2009年   2105篇
  2008年   967篇
  2007年   730篇
  2006年   856篇
  2005年   636篇
  2004年   469篇
  2003年   436篇
  2002年   376篇
  2001年   423篇
  2000年   318篇
  1999年   413篇
  1998年   534篇
  1997年   502篇
  1996年   551篇
  1995年   396篇
  1994年   317篇
  1993年   274篇
  1992年   194篇
  1991年   174篇
  1990年   149篇
  1989年   155篇
  1988年   142篇
  1987年   141篇
  1986年   105篇
  1985年   105篇
  1984年   82篇
  1983年   93篇
  1982年   84篇
  1981年   70篇
  1980年   51篇
  1979年   36篇
  1978年   37篇
  1977年   48篇
  1976年   33篇
  1974年   32篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Murdoch Eaton DG, Wertheim D, Oozeer R, Dubowitz LMS, Dubowitz V. Reversible changes in cerebral activity associated with acidosis in preterm neonates. Acta Paediatr 1994;83:486–92. Stockholm. ISSN 0803–5253
Computerized online EEG monitoring in ventilated preterm infants less than 32 weeks' gestation enabled evaluation of the effect of acidosis on cerebral function. All episodes of acidosis were found to be associated with changes in the levels of cerebral activity. In 21 of the 32 episodes, EEG activity returned to pre-acidosis levels after therapeutic intervention. The duration of EEG abnormality was related to the severity of acidosis. However, the time to recovery of the EEG after therapeutic procedures was not related to duration of the EEG change.  相似文献   
102.
103.
When complex prostheses are fabricated, it is expected that at some point maintenance will be necessary. This clinical report documents a 10-year-old maxillary spark erosion prosthesis that had been repaired many times, was discolored, and exhibited significant signs of wear. The metal superstructure was intact; therefore, only the acrylic resin base and teeth needed to be replaced. To reduce both cost and time without the prosthesis for the patient, the rehabilitation was completed within 24 hours.  相似文献   
104.
105.
106.
107.
Transforming growth factor-beta(2) promotes healing in a variety of animal models and exhibits clinical effects thought to be mediated by connective tissue formation. Two clinical trials were conducted to evaluate the safety and effect of transforming growth factor-beta(2) purified from bovine bone and delivered topically to venous stasis ulcers three times per week for up to 6 weeks by means of a lyophilized collagen vehicle. The first was an open-label trial comparing transforming growth factor-beta(2) purified from bovine bone (0.5 microg/cm(2)) with a placebo consisting of lyophilized collagen vehicle-without active drug. After no safety issues arose in that trial, a prospectively randomized, closed-label, observer-blinded, three-armed trial was conducted to compare bovine transforming growth factor-beta(2) (2.5 microg/cm(2)) with the collagen matrix placebo vehicle and with a standard dressing. Standardized elastic compression was applied to all test extremities. The rate of reduction of ulcer area as measured by planimetry was the primary measure of effect. No serious safety-related events occurred in either trial. Clinical evaluation suggested that improvement in the quality and quantity of granulation tissue appeared to precede epithelialization of ulcers treated with bovine transforming growth factor-beta(2). In both studies, treatment with bovine transforming growth factor-beta(2) appeared to have a positive effect on the rate of ulcer closure, whereas ulcers in the control groups continued to exhibit impaired healing. In the open-label study, the mean rate of closure of ulcers treated with bovine transforming growth factor-beta(2) was significantly greater than that of ulcers treated with placebo. There was likewise enhanced reduction in ulcer area in the ulcers treated with bovine transforming growth factor-beta(2) in the second trial. However, because of a higher variability in patient response and a greater placebo effect, the difference was not significant. The placebo was not worse than the standard care arm, thereby showing that the vehicle is not injurious to healing. The combined results of the two trials suggest that, at doses of 0.5 to 2.5 microg/cm(2), bovine transforming growth factor-beta(2) is safe as a topically applied agent in a collagen matrix vehicle and can have a positive effect on closure of venous stasis ulcers. Large multicenter trials appear to be indicated to evaluate fully the potential utility of transforming growth factor-beta(2) in accelerating closure of chronic dermal ulcers.  相似文献   
108.
Occupational exposure to HIV is becoming a daily hazard in many emergency departments. Emergency physicians who are protected by disability insurance policies are likely to believe that if they are unable to continue working because of HIV-positive status, their disability policies will provide them with a source of income. Unfortunately, analysis of case law regarding claims under disability policies shows that the law is unlikely to consider an asymptomatic, HIV-positive physician disabled for purposes of payments under disability policies. Therefore, it is necessary for emergency physicians to make sure this issue is resolved before buying and relying on a disability policy so that an anticipated safety net will be operative over the full range of hazards that emergency physicians face.[Lavely R: The HIV-positive physician and disability insurance. Ann Emerg Med June 1994;23:1355-1362.]  相似文献   
109.
Confidentiality is a promise rooted in tradition, law andmedical ethics. Emergency physicians treat a variety of patients to whom confidentiality is of vital importance: employees, celebrities, victims of violence or disaster, minors, students, criminals, drug abusers, and patients with STDs. EDs should develop methods of ensuring confidentiality for all patients.34Although confidentiality is an important principle thatshould be respected and guarded, it is not absolute. Various laws mandate disclosure of certain patient information; in addition, an overriding moral duty may occasionally require, a breach of confidentiality. As Beauchamp and Childress noted, “the therapeutic role may sometimes have to yield to ones role as citizen and as protector of the interests of others”.19 In general, however, circumstances requiring a breach of confidentiality are rare.  相似文献   
110.
Taking occlusal photographs can be challenging; they are by far the most difficult images to obtain. Achieving an ideal photograph of every arch may not always be possible. In patients with limited range of motion of the mandible, an oversized or hyperactive tongue, an excessive gag reflex, or reduced flexibility of lips and checks, the goal of an ideal occlusal photograph may not be achieved. Nevertheless, patience, practice, and attention to detail can often provide a satisfactory result.  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