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   704415篇
  免费   49926篇
  国内免费   1296篇
耳鼻咽喉   9167篇
儿科学   23255篇
妇产科学   17598篇
基础医学   110386篇
口腔科学   19949篇
临床医学   63678篇
内科学   134194篇
皮肤病学   16159篇
神经病学   49415篇
特种医学   25726篇
外国民族医学   76篇
外科学   104451篇
综合类   14808篇
现状与发展   2篇
一般理论   160篇
预防医学   51311篇
眼科学   16303篇
药学   53974篇
  3篇
中国医学   2354篇
肿瘤学   42668篇
  2019年   5433篇
  2018年   7859篇
  2017年   6106篇
  2016年   6818篇
  2015年   7550篇
  2014年   10261篇
  2013年   15378篇
  2012年   20502篇
  2011年   21483篇
  2010年   12720篇
  2009年   11933篇
  2008年   19992篇
  2007年   21513篇
  2006年   21901篇
  2005年   20437篇
  2004年   19985篇
  2003年   18945篇
  2002年   18463篇
  2001年   36341篇
  2000年   36913篇
  1999年   30395篇
  1998年   7881篇
  1997年   6665篇
  1996年   6971篇
  1995年   6630篇
  1994年   6098篇
  1993年   5590篇
  1992年   22974篇
  1991年   22929篇
  1990年   22319篇
  1989年   22091篇
  1988年   20045篇
  1987年   19422篇
  1986年   18469篇
  1985年   17311篇
  1984年   12703篇
  1983年   10742篇
  1982年   5922篇
  1979年   11521篇
  1978年   8130篇
  1977年   6832篇
  1976年   6598篇
  1975年   7270篇
  1974年   8501篇
  1973年   8149篇
  1972年   7663篇
  1971年   7129篇
  1970年   6878篇
  1969年   6309篇
  1968年   5782篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
153.
We investigated the effects of the noble gas argon on the expression of locomotor sensitization to amphetamine and amphetamine-induced changes in dopamine release and mu-opioid neurotransmission in the nucleus accumbens. We found (1) argon blocked the increase in carrier-mediated dopamine release induced by amphetamine in brain slices, but, in contrast, potentiated the decrease in KCl-evoked dopamine release induced by amphetamine, thereby suggesting that argon inhibited the vesicular monoamine transporter-2; (2) argon blocked the expression of locomotor and mu-opioid neurotransmission sensitization induced by repeated amphetamine administration in a short-term model of sensitization in rats; (3) argon decreased the maximal number of binding sites and increased the dissociation constant of mu-receptors in membrane preparations, thereby indicating that argon is a mu-receptor antagonist; (4) argon blocked the expression of locomotor sensitization and context-dependent locomotor activity induced by repeated administration of amphetamine in a long-term model of sensitization. Taken together, these data indicate that argon could be of potential interest for treating drug addiction and dependence.  相似文献   
154.
Laparoscopic surgery has several advantages over traditional surgery because it has been shown to be less invasive. The next logical step in the evolution of minimally invasive surgery may be to eliminate all abdominal incisions. The natural orifices provide a port of entry via the gastrointestinal tract to the peritoneal cavity. This approach would require the creation of a perforation, which is considered to be a major complication of endoscopy with significant morbidity and mortality. However, there are several recent studies that have described the technical feasibility and safety of a per‐oral transgastric approach to the peritoneal cavity using conventional endoscopes. Theoretically, this approach could reduce postoperative abdominal wall pain, wound infection, hernia formation, and adhesions. This article aims to summarize the current status of transgastric surgery, currently referred to as natural orifice transluminal endoscopic surgery (NOTES), and to address some of its future challenges.  相似文献   
155.
The incidence of hematological malignancies during pregnancy is low, and treatment in this setting is problematic. This study observed 21 pregnancies in 18 patients with hematological malignancies. Patients’ ages were between 19 and 43 (median 25) years. Two pregnancies ended with spontaneous abortion, one pregnancy ended with in utero death, three therapeutic abortions were carried out, and 15 infants were born alive but three of them died later. The median birth weight was 2.47 kg. Twelve babies survived to a median age of 36 (range 4–117) months. Eight babies were exposed to chemotherapy during the in utero period. One baby was exposed to chemotherapy during all the trimesters and was born prematurely and later died because of intracranial bleeding. Four babies were exposed to chemotherapy during the first trimester, one of them had low birth weight and floating thumb malformation, two of them had only low birth weight, and one was born healthy, but died at 3 months of age as a result of severe gastroenteritis. Two babies were exposed to chemotherapy during the second and third trimesters; one of them had low birth weight, and the other pregnancy ended in in utero death. One infant was exposed to chemotherapy during the third trimester and was born at term, but died because of pulmonary hemorrhage. We concluded that chemotherapy during all trimesters of pregnancy carries a significant risk for an unfavorable outcome.  相似文献   
156.
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed.  相似文献   
157.
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes.  相似文献   
158.
The intention of this article is to introduce the reader to the Transograph from a historical perspective. The technical data presented are intended to help the reader understand the design of this unique instrument and how it was programmed, but will not provide the reader a thorough understanding of this philosophy. The article seeks neither to defend nor criticize the principles of Transographics.  相似文献   
159.
Background Percutaneous abdominal aortic aneurysm(AAA) repair has been previously described using the "preclose"technique and general endotrachial anesthesia (GA).  相似文献   
160.
背景/目的:从1978-2000年,有10对联体双胞胎成功接受了手术分离,结果14人存活。其中6对是因为他们的联体同胞死亡或濒临死亡而接受紧急分离手术。剩余的4对,每对至少一个同胞接受至少一次的急诊手术后,才接受联体分离手术。方法:对这一独特的队列进行包含6个项目的问卷调查。问题的设计是开放式的,为父母/家庭提供有关信息的最大机会。对每个家庭就相同的问题也进行了当面的问卷调查。医师询问了与身体健康和疾病相关的一些问题。而社会工作询问了与发育、教育、社会心理和家庭功能相关的问题。结果:前面提及的14人存活的双胞胎中,4人大学毕业,1人于1981年完成中学学业,剩余9人正在上学。14人在最初的手术后,还需要接受再次手术,尤其是需要矫正泌尿系统、畸形、神经外科和小儿外科的问题。结论:通过超声检查对联体双胎进行宫内诊断,可以使医师和胎儿父母在孕早期决定在终止妊娠时是进行双胎分离还是保全其中一个。这些病例报道通过描述14例手术存活的长期体格检查和心理学检查结果,为医师和父母在关键时刻做出决定提供了另外有助的依据。  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