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   917篇
  免费   45篇
  国内免费   38篇
耳鼻咽喉   21篇
儿科学   69篇
妇产科学   10篇
基础医学   90篇
口腔科学   40篇
临床医学   119篇
内科学   172篇
皮肤病学   24篇
神经病学   29篇
特种医学   189篇
外科学   57篇
综合类   27篇
预防医学   55篇
眼科学   16篇
药学   47篇
中国医学   3篇
肿瘤学   32篇
  2023年   3篇
  2021年   12篇
  2020年   5篇
  2019年   12篇
  2018年   22篇
  2017年   13篇
  2016年   13篇
  2015年   19篇
  2014年   16篇
  2013年   35篇
  2012年   21篇
  2011年   16篇
  2010年   47篇
  2009年   45篇
  2008年   16篇
  2007年   29篇
  2006年   21篇
  2005年   40篇
  2004年   15篇
  2003年   7篇
  2002年   13篇
  2001年   19篇
  2000年   10篇
  1999年   23篇
  1998年   48篇
  1997年   49篇
  1996年   51篇
  1995年   33篇
  1994年   41篇
  1993年   37篇
  1992年   15篇
  1991年   16篇
  1990年   12篇
  1989年   28篇
  1988年   43篇
  1987年   23篇
  1986年   17篇
  1985年   31篇
  1984年   7篇
  1982年   7篇
  1981年   10篇
  1980年   9篇
  1979年   8篇
  1978年   5篇
  1977年   6篇
  1976年   13篇
  1975年   4篇
  1974年   2篇
  1971年   2篇
  1969年   2篇
排序方式: 共有1000条查询结果,搜索用时 375 毫秒
1.
2.
3.
BACKGROUND: Vitiligo is the most common pigmentary disorder with a global incidence from 0.1% to 2% in different geographical areas. Histopathology and histochemistry have shown the reduction of melanocytes in achromic patches, but microscopic changes of lesional and non-lesional skin are still not completely understood. Reflectance confocal microscopy (RCM), based on the different light reflectance index of cutaneous structures, allowed in vivo, en face microscopic evaluation of superficial skin layers with a resolution similar to skin histology. AIM: The purpose of this study was to evaluate RCM features of lesional and non-lesional skin of vitiligo patients. Moreover, re-pigmented areas were taken into consideration in order to evaluate melanocyte response to ultraviolet B (UVB) radiation. SUBJECTS AND METHODS: Sixteen patients of different phototypes affected by active non-segmental vitiligo and 10 controls were enrolled in the study. In vivo skin imaging was done using a commercially available RCM (Lucid, Vivascope 1500. Re-pigmented areas from 6 to 16 patients (after UVB narrow-band therapy) were also examined. RESULTS: Vitiligo lesions showed the disappearance of the bright rings normally seen at the dermo-epidermal junction. Moreover, non-lesional skin of vitiligo patients showed unexpected changes as the presence of half-rings or scalloped border-like features of the bright papillary rings. In re-pigmented areas after UVB narrow band therapy, the presence of activated, dendritic melanocytes was seen. CONCLUSIONS: Considering our results, and following further studies, RCM clinical applications could be used in the therapeutic monitoring and evaluation of the evolution of vitiligo.  相似文献   
4.
5.
6.
Aging is associated with a dysregulation of the immune system known as immunosenescence. Immunosenescence involves cellular and molecular alterations that impact both innate and adaptive immunity, leading to increased incidences of infectious disease morbidity and mortality as well as heightened rates of other immune disorders such as autoimmunity, cancer, and inflammatory conditions. While current data suggests physical activity may be an effective and logistically easy strategy for counteracting immunosenescence, it is currently underutilized in clinical settings. Long-term, moderate physical activity interventions in geriatric populations appear to be associated with several benefits including reduction in infectious disease risk, increased rates of vaccine efficacy, and improvements in both physical and psychosocial aspects of daily living. Exercise may also represent a viable therapy in patients for whom pharmacological treatment is unavailable, ineffective, or inappropriate. The effects of exercise impact multiple aspects of immune response including T cell phenotype and proliferation, antibody response to vaccination, and cytokine production. However, an underlying mechanism by which exercise affects numerous cell types and responses remains to be identified. Given this evidence, an increase in the use of physical activity programs by the healthcare community may result in improved health of geriatric populations.  相似文献   
7.
8.
In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications.  相似文献   
9.
Winkler  ML; Olsen  WL; Mills  TC; Kaufman  L 《Radiology》1987,165(1):203-207
Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study.  相似文献   
10.
本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4~5.6%,血浓69.6~1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。  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