首页 | 官方网站   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   18647篇
  免费   901篇
  国内免费   121篇
医药卫生   19669篇
  2023年   123篇
  2022年   130篇
  2021年   480篇
  2020年   275篇
  2019年   401篇
  2018年   495篇
  2017年   360篇
  2016年   494篇
  2015年   494篇
  2014年   697篇
  2013年   887篇
  2012年   1365篇
  2011年   1361篇
  2010年   794篇
  2009年   723篇
  2008年   1308篇
  2007年   1176篇
  2006年   1246篇
  2005年   1157篇
  2004年   1121篇
  2003年   1010篇
  2002年   919篇
  2001年   187篇
  2000年   146篇
  1999年   213篇
  1998年   198篇
  1997年   167篇
  1996年   131篇
  1995年   132篇
  1994年   113篇
  1993年   117篇
  1992年   117篇
  1991年   97篇
  1990年   107篇
  1989年   80篇
  1988年   68篇
  1987年   74篇
  1986年   74篇
  1985年   54篇
  1984年   84篇
  1983年   54篇
  1982年   57篇
  1981年   39篇
  1980年   45篇
  1979年   26篇
  1978年   32篇
  1977年   22篇
  1976年   19篇
  1974年   20篇
  1972年   19篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
With easy chemical synthesis from its precursor, methamphetamine (MA) is now widespread in many countries. The abuse of methamphetamine is associated with several negative effects on health, because MA is a neurotoxin and a dangerous central nervous system stimulant. It changes levels of neurotransmitters in the brain, releasing dopamine and inhibiting nor epinephrine uptake which increases sympathetic nervous system activity and can lead to cardiac arrhythmia, hypertension and tachypnea. The consequences of MA abuse are clearly manifested in oral diseases (like “meth mouth”) which is characterised by extensive caries, teeth grinding with ensuing dental wear and trismus. The present review was designed to fill the gap in knowledge about methamphetamine abuse in the European Union (EU) and to illustrate the main clinical effects of prolonged use. After describing the pharmacology and systemic effects of methamphetamine and concentrating on its effects on the mouth, the present review compares the epidemiology and incidence of abuse in the world, particularly the USA and the EU. Key words:Methamphetamine, “Meth mouth”, drug abuse, oral health.  相似文献   
3.
4.
5.
6.
7.

Background and objective

Erector spinae plane block is a valid technique to provide simultaneously analgesia for combined thoracic and abdominal surgery.

Case report

A patient underwent open esophagectomy followed by reconstructive esophagogastroplasty but refused thoracic epidural analgesia; a multi‐modal analgesia with a multiple erector spinae plane block was then planned. Three erector spinae plane catheters (T5 and T10 on the right side and T9 on the left side) for continuous analgesia were placed before surgery. During the first 48 h pain was never reported in the thoracic area but the patient reported multiple times to feel a pain well localized in epigastrium, but never localized in any other abdominal quadrant.

Discussion

Erector spinae plane block is a valid technique to provide analgesia simultaneously for combined thoracic and abdominal surgery and could be a valid alternative strategy if the use of epidural analgesia is contraindicated.  相似文献   
8.
ABSTRACT

Introduction: Steroid hormones are responsible for specific changes in the endometrium during the menstrual cycle, when they are sequentially secreted and, because of this, in the early days sequential combined oral contraceptive regimens were utilized. The same basic concept has been utilized with multi-phasic regimens, in order to produce endometrial pictures mimicking the normal cycle.

Areas covered: The Endometrial effects of progestins and estrogens; combined monophasic high- (50 μg), medium- (30 μg), low- (20 μg), ultralow- (15 μg) estrogen content; sequential regimens; multiphasic combinations; treatment schedules.

Cervical effects of combined high-dose and sequential combinations, including evidence for an increase in malignant lesions.

Expert opinion: Overall, combined oral contraceptives (COCs) inhibit normal proliferative changes and the endometrium becomes thin, narrow, with widely spaced glands and pre-decidual changes in the stroma. During the first few cycles the progestin induces a coexistence of proliferative and secretory features; with time, the picture changes because the progestin induces a down-regulation of estrogen receptors, resulting in tortuous glands similar to those in the secretory phase, but characterized by a quiescent, atrophic glandular epithelium.

In the cervical epithelium, under the influence of high-dose COCs, endocervical glands became hypersecretory and in some instances, distinctive type of atypical polypoid endocervical hyperplasia is found.  相似文献   
9.
10.
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-23

京公网安备 11010802026262号