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   868篇
  免费   99篇
  国内免费   28篇
耳鼻咽喉   4篇
儿科学   33篇
妇产科学   12篇
基础医学   123篇
口腔科学   10篇
临床医学   111篇
内科学   209篇
皮肤病学   31篇
神经病学   136篇
特种医学   81篇
外科学   69篇
综合类   20篇
预防医学   30篇
药学   62篇
中国医学   1篇
肿瘤学   63篇
  2022年   13篇
  2021年   16篇
  2020年   10篇
  2019年   13篇
  2018年   20篇
  2017年   18篇
  2016年   25篇
  2015年   44篇
  2014年   26篇
  2013年   36篇
  2012年   53篇
  2011年   39篇
  2010年   24篇
  2009年   32篇
  2008年   53篇
  2007年   54篇
  2006年   37篇
  2005年   35篇
  2004年   13篇
  2003年   21篇
  2002年   12篇
  2001年   10篇
  2000年   9篇
  1999年   18篇
  1998年   23篇
  1997年   19篇
  1996年   31篇
  1995年   10篇
  1994年   19篇
  1993年   8篇
  1992年   7篇
  1991年   8篇
  1990年   13篇
  1989年   8篇
  1988年   22篇
  1987年   13篇
  1986年   14篇
  1985年   18篇
  1984年   9篇
  1983年   9篇
  1982年   10篇
  1981年   10篇
  1980年   7篇
  1979年   8篇
  1978年   14篇
  1977年   14篇
  1976年   11篇
  1975年   9篇
  1971年   7篇
  1970年   5篇
排序方式: 共有995条查询结果,搜索用时 15 毫秒
1.
2.
Pityriasis rosea (PR) is a relatively common disease although its aetiology has not yet been identified. It occurs worldwide and there is no racial susceptibility factor. It usually affects teenagers and young adults between 10 and 35 years of age. Typical PR is much easier to diagnose than the rare atypical forms. We report a rare case of vesicular PR in a black woman who had vesicular lesions limited to her palms and soles in addition to regular typical lesions. We devised an efficient oral erythromycin treatment for this patient.  相似文献   
3.
4.
The endoscopic examination of the large intestine can be considered today a routine examination in internal medicine. Since the introduction of flexible videoendoscopy, evaluating diseases in the distal colon using rectoscopy has become less important. Ano-proctoscopy is an obligatory component for a complete colon diagnostic after a flexible ileo-colonoscopy has been performed. Colonoscopy has improved significantly the diagnosis and therapy of diseases in the large intestine since it has been introduced more than 30 years ago. By introducing modern videocolonoscopy in addition to other instruments, there is today a broad spectrum of diagnostic and therapeutic indications available. Specifically, due to its frequency and prognostic relevance, colonoscopy has become the most powerful and important procedure in the early detection and prevention of colon cancer.  相似文献   
5.
6.
7.
8.
进一步研究了抗三尖杉酯碱的HL-60细胞(HR20)抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明,环孢菌素A(CsA)20,10μg·ml ̄(-1)诱导HL-60细胞发生凋亡,而阻断HR20细胞于G_1期,就不能诱导细胞发生凋亡。低浓度的CsA明显增加柔红霉素在HR20细胞内的积聚,其逆转抗药性作用与阻断细胞周期运行无关。CsA10μg·ml ̄(-1)处理HR20细胞,可引起50kDa的蛋白质高度磷酸化。结果提示:环孢菌素A阻断抗三尖杉酯碱的HL-60细胞于G_1期,而诱导敏感的HL-60细胞发生凋亡,其阻断作用与抗药性无关  相似文献   
9.
Summary Daily diary records of sleep and activity, and 4-h measurements of body temperature, performance and subjective alertness were collected on board ship from 15 watchkeepers on the 4-on/8-off system, and from 28 dayworkers, on both westward and eastward transatlantic voyages. The data from a balanced sample of the subjects were analysed over selected 8-d periods of the voyages where four or five time zones were crossed. During these periods the average amount of daily sleep obtained by dayworkers on the eastward voyage was more than 1 h less than that on the westward voyage, and its quality was rated lower. Watchkeepers' main sleep was also shorter when travelling eastward, but this reduction was partially compensated for by a slightly longer secondary sleep. With the exception of subjective alertness on the eastward voyage, the basic phase of the circadian rhythms in the measured variables adjusted appropriately to the clock changes associated with the time zone crossings. The normal shape of the average daily curves was, however, altered differentially in the two directions of travel; as a result, morning levels of all variables were lower on the eastward voyage than on the westward, but evening levels were higher. These distortions of rhythm waveforms, which probably arose from a combination of endogenous and exogenous factors, add another dimension to the basic problem caused by the effects of circadian rhythms on operational efficiency in the shipboard situation. This problem can only be solved by the development of alternative watchkeeping systems which take full account of these rhythms.Partly supported by a grant from the West German Ministry for Technology and Research, Project Schiff der Zukunft, Part ET 83b  相似文献   
10.
Summary Sleep length and sleep quality scores were collected on board ships over periods of up to two weeks from 38 watchkeepers working a 4-on/8-off routine and 29 dayworkers. All watchkeepers exhibited fragmented sleeping patterns, which indicated a lack of adaptation of the sleep/wakefulness cycle to the hours of work. There were only slight differences in total sleep length between watchkeepers and dayworkers, however, both groups did not obtain an adequate amount of sleep. Within the watchkeeping crews the 3rd Officers had by far the shortest sleep length. Concerning sleep quality, daytime sleep was generally given the lowest ratings, whereas sleep starting before midnight was on average evaluated as the best, both by watchkeepers and dayworkers. Watchkeeping personnel do not normally have any days off during a voyage so that missed sleep might even amount to a sleep deficit. A solution for this problem could perhaps be a new, stabilized system that allows a single uninterrupted sleep, which is required for full recuperation, to be taken each day.Dedicated to Professor J. Aschoff on the occasion of his 75th birthdayPartly supported by a grant from the Ministry for Technology and Research, Federal Republic of Germany, Project Schiff der Zukunft, Part ET83b  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