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   1058篇
  免费   53篇
  国内免费   35篇
耳鼻咽喉   17篇
儿科学   82篇
妇产科学   4篇
基础医学   129篇
口腔科学   29篇
临床医学   122篇
内科学   162篇
皮肤病学   22篇
神经病学   69篇
特种医学   221篇
外科学   50篇
综合类   24篇
预防医学   46篇
眼科学   19篇
药学   104篇
中国医学   1篇
肿瘤学   45篇
  2021年   9篇
  2020年   3篇
  2019年   9篇
  2018年   18篇
  2017年   12篇
  2016年   10篇
  2015年   20篇
  2014年   16篇
  2013年   29篇
  2012年   29篇
  2011年   20篇
  2010年   50篇
  2009年   42篇
  2008年   22篇
  2007年   30篇
  2006年   30篇
  2005年   55篇
  2004年   26篇
  2003年   25篇
  2002年   24篇
  2001年   29篇
  2000年   22篇
  1999年   35篇
  1998年   53篇
  1997年   50篇
  1996年   51篇
  1995年   40篇
  1994年   44篇
  1993年   38篇
  1992年   21篇
  1991年   22篇
  1990年   13篇
  1989年   27篇
  1988年   48篇
  1987年   25篇
  1986年   18篇
  1985年   34篇
  1984年   7篇
  1983年   4篇
  1982年   6篇
  1981年   8篇
  1980年   9篇
  1979年   6篇
  1978年   5篇
  1977年   6篇
  1976年   12篇
  1975年   3篇
  1971年   3篇
  1936年   3篇
  1934年   3篇
排序方式: 共有1146条查询结果,搜索用时 15 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.
Congenital herpes simplex retinitis   总被引:2,自引:0,他引:2  
An 1,810-g girl born at 37 weeks of gestation had true congenital herpes simplex virus type 2 infection. The neonate was born with hypo-pigmented skin lesions, brain lesions, and old heavily pigmented retinal scars in the posterior pole. There was no active ocular disease. Viral cultures, immunoperoxidase stains, and antibody determination by enzyme-linked immunosorbent assay were all positive for herpes simplex virus. Treatment with acyclovir healed the lesions within ten days. The clinical and laboratory findings indicated that the herpetic infection probably occurred in the second trimester.  相似文献   
5.
6.
Poly{acrylamide-co-[2-(acryloyloxy)ethyltrimethylammonium chloride]} (1) , Poly{acrylamide-co-[2-(methacryloyloxy)ethyltrimethylammonium chloride]} (2) and Poly{acrylamide-co-[3-(acryloylamino)propyltrimethylammonium chloride]} (3) with cationic monomeric unit mole fractions of 8, 25, and 50 mol-%, and the corresponding homopolymers were characterized with respect to their molecular dimensions in 1 M sodium chloride solution at 25°C in the molecular weight range from 200000 to 16000000, using light-scattering and viscometric measurements. It was possible to establish correlations between molecular weight, intrinsic viscosity and radius of gyration. Whereas a steady increase in the exponents of the [η] vs. M- and 〈R2G0,5 vs. M-relationships can be observed with increasing charge density, there is an initial decrease in the values of the exponents for 2 and 3 , when 8 mol-% of the cationic monomer is inserted into poly-acrylamide. If the charge density is increased further, these values can also be seen to rise steadily. The findings are explained by the different structures in solution, which are formed by the copolymers and homopolymers investigated due to their chemical structure. The radii of gyration were calculated from the intrinsic viscosities with the aid of the Flory-Fox equation. However, neither the results obtained with the Flory-Fox constant Φ0= 3,69. 1024 mol?1, nor those with the value of Φ0= 2,10. 1024 mol?1 showed good agreement with the experimentally recorded data.  相似文献   
7.
8.
9.
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   
10.
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   
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