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   554篇
  免费   27篇
  国内免费   5篇
耳鼻咽喉   2篇
儿科学   21篇
妇产科学   4篇
基础医学   38篇
口腔科学   15篇
临床医学   112篇
内科学   78篇
皮肤病学   13篇
神经病学   14篇
特种医学   117篇
外科学   36篇
综合类   50篇
预防医学   30篇
眼科学   5篇
药学   34篇
  1篇
中国医学   2篇
肿瘤学   14篇
  2021年   4篇
  2020年   3篇
  2019年   2篇
  2018年   5篇
  2017年   5篇
  2016年   3篇
  2015年   33篇
  2014年   43篇
  2013年   25篇
  2012年   18篇
  2011年   31篇
  2010年   22篇
  2009年   23篇
  2008年   21篇
  2007年   26篇
  2006年   26篇
  2005年   11篇
  2004年   11篇
  2003年   10篇
  2002年   10篇
  2001年   8篇
  2000年   6篇
  1999年   11篇
  1998年   14篇
  1997年   14篇
  1996年   17篇
  1995年   20篇
  1994年   24篇
  1993年   11篇
  1992年   2篇
  1991年   3篇
  1989年   10篇
  1988年   9篇
  1987年   6篇
  1986年   9篇
  1985年   22篇
  1984年   7篇
  1983年   6篇
  1982年   3篇
  1981年   10篇
  1980年   8篇
  1978年   6篇
  1977年   9篇
  1976年   5篇
  1972年   2篇
  1970年   2篇
  1966年   1篇
  1965年   1篇
  1962年   1篇
  1957年   1篇
排序方式: 共有586条查询结果,搜索用时 15 毫秒
21.
The aim of this study is to investigate whether three mononucleotide polymorphisms at the locus -1082,-819 and -592 in the promoter region of the IL-10 gene are associated with chronic severe hepatitis. The IL-10-592 and IL-10-1082 polymorphisms were genotyped by polymerase chain reactionrestriction fragment length polymorphism analysis (PCR-RFLP) while polymerase chain reaction-sequence specific primer (PCR-SSP) assay was used to test the IL-10-819 polymorphism. The polymorphisms of IL-10-1082, -819 and -592 genes were detected in 98 patients with chronic severe hepatitis (CSH), 478 patients with chronic hepatitis B (CHB), 223 asymptomatic (chronic) HBV carriers (ASC) and 267 patients with self-restricted HBV. There was significant difference of the polymorphisms of IL-10-1082, IL-10-819 and IL-10-592 genes between CSH group and other groups. The frequency of AA genotype at IL-10 gene promoter -1082 locus in chronic severe hepatitis patients was higher than that in asymptomatic HBV carriers (2 = 13. 314, P = 0.001), and self-restricted HBV patients (χ^2 = 13.545, P = 0.000); the frequency of CC and AC genotype at IL-10 gene promoter -592 locus in chronic severe hepatitis patients was higher than that in chronic hepatitis patients(χ^2 = 15.970, P=0.000) (χ^2 =20.414, P=0.000), asymptomatic HBV carriers (χ^2 =21.283, P= 0.000) (χ^2 = 28.309, P = 0.000) and self-restricted HBV patients(χ^2 = 17.047, P = 0.000) (χ^2 = 16.528, P = 0.000) ; the frequency of TC genotype at IL-10 gene promoter -819 locus in chronic severe hepatitis patients was higher than that in chronic hepatitis patients(χ^2 = 58.961, P = 0.000), asymptomatic HBV carriers ( χ^2 = 53. 255, P = 0. 001 ) and self-restricted HBV patients (χ^2 = 39.616, P = 0.001). So interleukine-10 gene polymorphism was associated with the chronic severe hepatitis.  相似文献   
22.
23.
目的:探讨基质金属蛋白酶‐9(MMP‐9)、白细胞介素‐6(IL‐6)和白细胞介素‐10(IL‐10)与脑动脉粥样硬化斑块不稳定性以及脑梗死的关系。方法选择急性脑血管病患者56例,其中反复短暂性脑缺血发作(TIA)16例,急性脑梗死40例。对照组为21例健康体检者。所有缺血性脑血管病患者均经头CT血管造影(CTA)检查或颈部血管超声证实存在不稳定斑块,且发病机制考虑与不稳定斑块破裂有关。采用ELISA方法检测各组血清MMP‐9、IL‐6和IL‐10水平并进行比较。结果急性脑梗死组患者血清中MMP‐9、IL‐10水平分别为(137.10±69.38)ng/mL和(39.16±32.82)pg/mL,TIA组患者血清中MMP‐9、IL‐10水平分别为(119.79±65.54)ng/mL和(33.00±21.36)pg/mL,均明显高于对照组〔分别为(65.42±36.81)ng/mL和(19.83±12.16)pg/mL〕;脑梗死组患者血清MMP‐9及IL‐10水平均高于TIA组(均P<0.05)。各组间IL‐6水平差异无统计学意义(均P>0.05)。结论MMP‐9和IL‐10水平升高可能与动脉粥样硬化不稳定斑块破裂以及脑梗死灶形成有关。  相似文献   
24.
Wilson  AJ; Totty  WG; Murphy  WA; Hardy  DC 《Radiology》1989,173(2):329-333
One hundred two computed tomographic (CT) arthrograms of the shoulder were retrospectively reviewed and compared with conventional double-contrast arthrograms from 101 patients (24 females and 77 males aged 9-70 years). One- to 4-year follow-up was obtained in 84 patients, 40 of whom underwent open-shoulder surgery or arthroscopy. Morphology of the normal portions of each labrum was categorized according to length, width, and tip shape. Correlation between morphology and age was weak, but abnormal labra were more common in younger patients. Conventional radiography was more accurate for detecting bony glenoid margin fractures, but CT was more accurate for detecting Hill-Sach fractures. CT was also more reliable than conventional arthrography in the detection of rotator cuff tears. Hence, few if any conventional radiographs are necessary between contrast material injection and CT imaging. A reduction in the number of images obtained will result in decreased radiation dose, less cost, and shorter examination time without loss of diagnostic accuracy.  相似文献   
25.
目的:探讨3D双回波稳态进动(dual echo steady state ,DESS)磁共振序列在显示椎管内臂丛神经的形态解剖学信息的情况,以及在显示突出椎间盘与椎管内臂丛神经的关系的临床应用价值。方法对35例有颈肩痛和上肢麻痛等颈丛和臂丛神经根受压症状,临床高度怀疑神经根型颈椎病患者行颈椎M RI常规序列(矢状位 T1 WI ,T2 WI ,横轴位T2WI)和3D DESS序列,3D DESS序列的所有图像均采用3D最大信号强度投影(MIP)与曲面重组等后处理,由2位高级职称M RI影像诊断医师通过对重建后图像所显示的臂丛神经椎管内神经根的形态、长度以及突出椎间盘与椎管内臂丛神经的关系的影像表现,评价3D DESS序列在神经根型颈椎病影像诊断中的临床应用价值。结果3D DESS序列重建图像和常规MRI T2WI序列图像对臂丛神经椎管内神经前根的显示率分别为94.3%(33/35)和88.6%(31/35),对臂丛神经椎管内神经后根的显示率分别为94.3%(33/35)和80%(28/35),3D DESS序列明显优于常规层厚 T2 WI图像,差异有显著性意义(P <0.05);在臂丛神经椎管内神经前后根完整性的显示方面,两者间差异无统计学意义(P >0.05)。结论3D DESS序列经重建后的图像,可提供更多的椎管内臂丛神经的形态解剖学信息,能清晰显示突出椎间盘对神经根的压迫情况,为临床治疗提供明确依据。  相似文献   
26.
27.
The existence and characteristics of bone marrow T-cell progenitors have not yet been established in man. Several pieces of evidence such as the reconstitution of certain immunodeficiencies by bone marrow graft suggest that T-cell precursors are present in the bone marrow. We report the growth of T-cell colonies from bone marrow populations using PHA-stimulated lymphocyte-conditioned medium containing T-cell growth factor (TCGF). Rosetting experiments and complement-dependent cytotoxicity assays with monoclonal antibodies indicate that the bone marrow T colony-forming cells (T-CFC) are E- OKT 3- and la+, i.e., immature progenitors. The colonies derived from these cells have the phenotype of mature T cells: E + OKT 3 + la- with either helper (OKT 4+) and suppressor (OKT 8 +) antigens. These results suggest that a thymic microenvironment may not be necessary for the in vitro proliferation and differentiation of the T-cell lineage in adult humans. These methodologies may permit direct investigation of early phenomena concerning the T-cell lineage, such as the acquisition of self-tolerance, the formation of a repertoire of specificities, and the HLA restriction phenomena that we believe takes place before the thymic maturation.  相似文献   
28.
Pressure, or compressive, erosions of bone in various locations in patients with rheumatoid arthritis are described. Possible pathophysiologic mechanisms that account for the appearance and distribution of these erosions include osteopenia, soft-tissue laxity, soft-tissue pressure on bone, bone pressure on bone, and muscular forces.  相似文献   
29.
Breast specimen radiography: evaluation of a compression device   总被引:1,自引:0,他引:1  
Chilcote  WA; Davis  GA; Suchy  P; Paushter  DM 《Radiology》1988,168(2):425-427
The irregular shape and uneven tissue thickness of excised breast specimens makes radiographic evaluation difficult, especially when calcifications are not present. Xeroradiographs before and after compression of 20 separate excised breast specimens were compared, and 17 of the same specimens were compared after compression combined with immersion in water. Specimen compression improved visibility of the lesion on average in 88% of cases, and visibility was equal in 12%. Combined compression/immersion further improved visibility of the lesion on average in 37% of cases. More significantly, evaluation of the compressed specimen led to a change in interpretation of the radiographs in 45% of cases. Compression of the specimen in specimen radiography is recommended in all cases in which pre-biopsy localization is performed.  相似文献   
30.
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