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   4455篇
  免费   313篇
  国内免费   67篇
耳鼻咽喉   68篇
儿科学   100篇
妇产科学   97篇
基础医学   346篇
口腔科学   315篇
临床医学   924篇
内科学   277篇
皮肤病学   19篇
神经病学   207篇
特种医学   176篇
外科学   759篇
综合类   588篇
预防医学   353篇
眼科学   141篇
药学   220篇
  8篇
中国医学   111篇
肿瘤学   126篇
  2024年   13篇
  2023年   84篇
  2022年   152篇
  2021年   233篇
  2020年   230篇
  2019年   145篇
  2018年   156篇
  2017年   180篇
  2016年   184篇
  2015年   200篇
  2014年   313篇
  2013年   287篇
  2012年   303篇
  2011年   270篇
  2010年   241篇
  2009年   208篇
  2008年   210篇
  2007年   212篇
  2006年   189篇
  2005年   131篇
  2004年   109篇
  2003年   104篇
  2002年   81篇
  2001年   67篇
  2000年   64篇
  1999年   49篇
  1998年   53篇
  1997年   38篇
  1996年   59篇
  1995年   16篇
  1994年   32篇
  1993年   24篇
  1992年   19篇
  1991年   23篇
  1990年   17篇
  1989年   19篇
  1988年   11篇
  1987年   16篇
  1986年   14篇
  1985年   16篇
  1984年   4篇
  1983年   7篇
  1982年   13篇
  1981年   9篇
  1980年   14篇
  1979年   3篇
  1977年   6篇
  1976年   1篇
  1974年   3篇
  1973年   2篇
排序方式: 共有4835条查询结果,搜索用时 15 毫秒
51.
Prostaglandin E1-induced hypotension (25% reduction from the preadministration level in mean arterial pressure) was applied to thirteen patients. Eight patients among them were operated in the supine position (group I) and other five in the prone position (group II). The maintenance dose of PGE1 was considerably lower in group II than in group I (0.067µg·kg–1·min–1 vs. 0.119µg·kg–1·min–1). In group I, there was a significant increase in CI, with a significant decrease in SVRI and PVRI during PGE1-induced hypotension. Such a high dose of PGE1 (0.119µg·kg–1·min–1) was considered to have a direct dilating action on the systemic resistance bed as well as on the pulmonary vasculature. It was considered that the suppression of hypoxic pulmonary vasoconstriction could be a mechanism to increase venous admixture during PGE1-induced hypotension. In group II, there was no significant increase in CI, and no significant decrease in SVRI and PVRI. PGE1-induced hypotension can be safely applied to the anesthetized patients, but we should be careful to apply it to the patients in the prone position, because lower dose of PGE1 can induce severe hypotension, which is not accompanied by the increase in CI as occures in the patients in the supine position.(Hirose M, Yoda K, Sakai K, et al.: Comparative Study on the cardio-respiratory change during prostaglandin E1-induced hypotention in the patients in the supine and prone position. J Anesth 5: 30–35, 1991)  相似文献   
52.
This Capsular Lens (ONG, type IV, to be called O.C.L.) has been developed for routinely performed extracapsular cataract extraction with lens implantation. The fundamental surgical procedure was based on continuing experience with the bimanual aspiration-irrigation technique and system developed by the author in 1971. The biomechanical properties of the asymmetric partly flexible, haptic loops are designed to give tensionfree fixation in two capsular pockets. The plano-anterior position of the lens ensures well-defined irido-lenticular clearance and proper alignment of the convex side with the posterior capsule. Consequently no iridectomy or iridotomy is needed for proper aqueous flow.  相似文献   
53.
Summary In 6 night nurses the daily course of body temperature and pulse rate was measured under strict resting conditions immediately after a 7 to 18-day period with night work as well as after a 10-day period of recovery under normal life conditions. Three of the subjects were morning types and three evening types according to the Horne-Östberg-Questionnaire as well as to the phase position of the body temperature cycle.In order to quantify the changes in amplitude, phase position, and frequency a flattening index, a circadian deformation index, and according to the calculated phase shift a corrected deformation index were used. While the evening types reacted with a flattening of their circadian amplitude and thus gained a greater tolerance, the morning types hyper reacted when exposed to the inverse life pattern, developing an increased amplitude and adding to the circadian deformation by ultradian periods. No significant differences could be detected in phase shift. Higher amounts of subjective complaints and deficit of sleep as well as differences in the additionally controlled vigilance functions demonstrated the lower tolerance of the morning types to night work.The discussion concerns the methological basis of a quantitative evaluation of disturbance of the circadian system, and shows off, that the greater tolerance of evening types to night work is based on a lower reagibility of the vegetative functions to changes in the outer environment.  相似文献   
54.
《红楼梦》里的诗词曲“如辐辏毂” ,是全书的有机构成。它不仅是浑然天成的画卷 ,还拨动着人物心灵的琴弦。  相似文献   
55.
Summary  In posterior fossa surgery, the sitting position offers a number of advantages believed to outweigh complications such as air embolism and pneumatocephalus. For this reason, the sitting position is frequently used in neurovascular decompression for trigeminal neuralgia. Two years ago we reported on a previously undescribed complication: permanent postoperative anosmia. Following the recent occurrence of a second case, we conducted a nationwide survey to determine the frequency of this complication. Permanent postoperative anosmia following surgical procedures in the sitting position has been observed in 3 other institutions. In addition, the survey revealed that only 40% of German neurosurgeons still favor the sitting position for surgery of the posterior cranial fossa.  Considering that permanent anosmia severely reduces quality of life, and that it can be avoided by using another position, the sitting position for surgical procedures in the posterior fossa should be restricted to special cases (e.g., brain stem tumors).  相似文献   
56.
一种新型颈椎椎弓根置钉定位器的研制   总被引:3,自引:1,他引:3  
介绍一种可三维调节的颈椎椎弓根置钉定位器,该装置作为钻模应用于颈椎椎弓根的钻孔定位,实现个体化置钉。给出了设计原理、使用方法,推导出椎弓根术前影像学数据与定位器钻套调整角的关系,并编制了计算应用软件。进行了功能评价和误差分析。  相似文献   
57.
判断企业是否滥用其优势地位应从质和量两个方面进行界定 ,把优势地位的构成和支配地位企业滥用行为的内在性质及表现统一起来 ,从而保证市场竞争公平有序进行。  相似文献   
58.

目的:描述伴有面转代偿头位的先天性单纯下直肌麻痹患者的临床表现,并分析其手术治疗效果。

方法:回顾性分析2014-05/2018-07伴有明显面转代偿头位的先天性下直肌麻痹患者,手术前后患者面转程度的变化借助骨科量角器来检查,垂直、水平斜视度变化通过三棱镜交替遮盖试验来测量,旋转斜视度变化通过眼底对眼球客观旋转状态评估。下直肌缩短术是主要治疗方案。

结果:在15例研究对象中,有13例行下直肌缩短术或者联合上直肌后徙术术后疗效好,下直肌运动不足明显改善,眼球运动协调,以面转为主的代偿头位消失,垂直、水平、旋转斜视得到矫正; 并得出:每缩短1 mm下直肌可矫正1.54±0.93°内旋斜视。而行下斜肌断腱术治疗的垂直斜视度小的患者,面转改善不理想,仍遗留眼球运动不协调。

结论:先天性单纯的下直肌麻痹以面转代偿头位为主,下直肌缩短术治疗效果好,轻度的过矫及欠矫不影响手术疗效。  相似文献   

59.
目的 探讨汉语发展性阅读障碍儿童与正常儿童调节功能与眼位各参数的变化,明确影响汉语发展性阅读障碍儿童视觉效率的关键视觉因素.方法 病例对照研究.选取天津市12所小学五年级学生1458名.根据识字量和瑞文智力的测验结果,筛选出98名汉语发展性阅读障碍儿童为试验组,随机选取年龄、性别、瑞文智力与之匹配的98名正常儿童为对照...  相似文献   
60.
目的观察手转胎头纠正枕位异常的效果,探讨施术时机、手法、注意事项。方法2004年1月至2005年12月在我院住院分娩,枕位异常者43例,采用手转胎头方法纠正。并设50例为对照组比较。结果手转胎头组43例成功37例,失败6例,成功率86%。两组结果提示,手转胎头组顺产率明显提高,剖宫产率明显下降,并发症无增加。结论徒手旋转持续性枕后位和枕横位可有效纠正异常胎位,变难产为顺产,降低剖宫产率。  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