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   2315篇
  免费   208篇
  国内免费   76篇
耳鼻咽喉   5篇
儿科学   34篇
妇产科学   16篇
基础医学   347篇
口腔科学   9篇
临床医学   202篇
内科学   343篇
皮肤病学   27篇
神经病学   293篇
特种医学   53篇
外国民族医学   2篇
外科学   136篇
综合类   313篇
现状与发展   1篇
预防医学   336篇
眼科学   7篇
药学   179篇
中国医学   29篇
肿瘤学   267篇
  2024年   3篇
  2023年   33篇
  2022年   38篇
  2021年   120篇
  2020年   102篇
  2019年   92篇
  2018年   85篇
  2017年   97篇
  2016年   92篇
  2015年   117篇
  2014年   147篇
  2013年   153篇
  2012年   165篇
  2011年   230篇
  2010年   245篇
  2009年   145篇
  2008年   97篇
  2007年   86篇
  2006年   87篇
  2005年   73篇
  2004年   52篇
  2003年   27篇
  2002年   40篇
  2001年   36篇
  2000年   19篇
  1999年   21篇
  1998年   18篇
  1997年   31篇
  1996年   21篇
  1995年   24篇
  1994年   18篇
  1993年   14篇
  1992年   13篇
  1991年   18篇
  1990年   12篇
  1989年   8篇
  1988年   3篇
  1987年   4篇
  1986年   3篇
  1985年   4篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
排序方式: 共有2599条查询结果,搜索用时 15 毫秒
1.
2.
3.
目的探讨血清TRAb IgG各亚型在不同活动分期甲状腺相关性眼病(thyroid-associated ophthalmopathy,TAO)患者中的分布特点,及其在评估TAO活动度中的价值。方法选取2018年8月至2019年2月郑州大学第一附属医院收治的TAO患者43例,依据临床活动度评分(clinical activity score,CAS)进一步分为活动期组(AP组,CAS≥3分,22例)和静止期组(IP组,CAS<3分,21例);Graves病患者(GD组)30例,桥本甲状腺炎患者(HT组)19例,并以同期健康体检者(NC组)50名作为正常对照。收集各组受试者临床基本资料,化学发光免疫法检测血清FT3、FT4、TSH、甲状腺过氧化物酶抗体(TPOAb)、甲状腺球蛋白抗体(TgAb)、促甲状腺激素受体抗体(TRAb)水平,酶联免疫吸附法检测血清TRAb IgG和IgG各亚型的百分结合率[binding rate in percentage,(B)],比较各亚型的阳性率和阳性亚型的相对含量。结果(1)与HT组相比,TAO组、GD组IgG1、IgG2阳性率降低,差异有统计学意义(P<0.05)。各疾病组间TRAb IgG亚型相对含量无明显差异(P>0.05)。(2)与IP组相比,AP组IgG1(B)、IgG1阳性率显著升高,IgG4(B)、IgG4相对含量显著降低(P<0.05)。(3)IgG1(B)与TAO活动度呈正相关(B=6.190,P=0.007),IgG4(B)越高越倾向于静止期,但差异无统计学意义(B=-16.390,P=0.052)。(4)活动率评估TAO处于活动期的受试者工作特征(ROC)曲线下面积为0.859(95%CI 0.746~0.973,P<0.05),当活动率为4.29时,约登指数最大,其判断敏感度为81.8%,特异度为81.0%。结论在TAO患者中血清TRAb IgG1水平升高提示疾病趋向活动期,IgG4水平升高提示疾病趋向静止期。活动率可为评估TAO是否处于活动期提供参考依据。  相似文献   
4.
5.
The tumor microenvironment (TME) is a vital component of tumor tissue. Increasing evidence suggests their significance in predicting outcomes and guiding therapies. However, no studies have reported a systematic analysis of the clinicopathologic significance of TME in lung adenocarcinoma (LUAD). Here, we inferred tumor stromal cells in 1184 LUAD patients using computational algorithms based on bulk tumor expression data, and evaluated the clinicopathologic significance of stromal cells. We found LUAD patients showed heterogeneous abundance in stromal cells. Infiltration of stromal cells was influenced by clinicopathologic features, such as age, gender, smoking, and TNM stage. By clustering stromal cells, we identified 2 clinically and molecularly distinct LUAD subtypes with immune active and immune repressed features. The immune active subtype is characterized by repressed metabolism and repressed proliferation of tumor cells, while the immune repressed subtype is characterized by active metabolism and active proliferation of tumor cells. Differentially expressed gene analysis of the two LUAD subtypes identified an immune activation signature. To diagnose TME subtypes practically, we constructed a TME score using principal component analysis based on the immune activation signature. The TME score predicted TME subtypes effectively in 3 independent datasets with areas under the receiver operating characteristic curves of 0.960, 0.812, and 0.819, respectively. In conclusion, we proposed 2 clinically and molecularly distinct LUAD subtypes based on tumor microenvironment that could be valuable in predicting clinical outcome and guiding immunotherapy.  相似文献   
6.
7.
This study aims to report the Budd-Chiari syndrome clinical research status and progress that has occurred in over nearly 30 years in China, and emphasize the value of imaging in facilitating the diagnosis of Budd-Chiari syndrome based on more than 2500 cases. Findings on ultrasonography, computed tomography, magnetic resonance imaging, and digital subtraction angiography images are used to propose new Budd-Chiari syndrome types and subtypes. The new subtype classification presented here has important value for guiding interventional treatment. This study also proposes a new concept of anatomical and functional obstruction of hepatic vein that stresses the compensatory value of accessory hepatic vein and azygos vein and describes the risk of manipulation of the communication branch of inferior vena cava obstruction in interventional therapy.  相似文献   
8.
Influenza A virus can quickly acquire genetic mutations that may be associated with increased virulence, host switching or antigenic changes. To provide new insights into the evolutionary dynamics and the adaptive strategies of distinct avian influenza lineages in response to environmental and host factors, we compared two distinct avian influenza epidemics caused by the H7N1 and H7N3 subtypes that circulated under similar epidemiological conditions, including the same domestic species reared in the same densely populated poultry area for similar periods of time.The two strains appear to have experienced largely divergent evolution: the H7N1 viruses evolved into a highly pathogenic form, while the H7N3 did not. However, a more detailed molecular and evolutionary analysis revealed several common features: (i) the independent acquisition of 32 identical mutations throughout the entire genome; (ii) the evolution and persistence of two sole genetic groups with similar genetic characteristics; (iii) a comparable pattern of amino acid variability of the HA proteins during the low pathogenic epidemics; and (iv) similar rates of nucleotide substitutions. These findings suggest that the evolutionary trajectories of viruses with the same virulence level circulating in analogous epidemiological conditions may be similar. In addition, our deep sequencing analysis of 15 samples revealed that 17 of the 32 parallel mutations were already present at the beginning of the two epidemics, suggesting that fixation of these mutations may occur with different mechanisms, which may depend on the fitness gain provided by each mutation. This highlighted the difficulties in predicting the acquisition of mutations that can be correlated to viral adaptation to specific epidemiological conditions or to changes in virus virulence.  相似文献   
9.
The clinical features of localized nasal rosacea have not been described in detail. This study was designed to analyze the subtypes and severity of localized nasal rosacea. Our present study included 30 patients with localized nasal rosacea. The erythematotelangiectatic subtype (13/30, 43.3%) was the most common type, followed by the phymatous subtype (9/30, 30%). The duration of rosacea was shorter and the severity of localized nasal rosacea was lower in the erythematotelangiectatic subtype cases compared with the patients with mixed or phymatous subtypes. Almost all of the papulopustular eruptions or phymatous lesions were associated with erythematotelangiectatic lesions. These findings suggest that the erythematotelangiectatic subtype may be considered the initial phase of localized nasal rosacea.  相似文献   
10.
亚健康人群亚型症状特征初探   总被引:25,自引:0,他引:25  
目的考察亚健康人群不同亚型的症状学特征。方法采用探索性因子分析的方法,以特征根λi≥1为公因子提取原则,对1 828例亚健康样本人群59个症状变量进行筛选归纳,分析亚健康状态亚型人群的症状特点。结果KMO统计量为0.85;Bartlett’s球形检验2χ=22 506.58,P<0.001;经主成分法因子分析,提取出17个公因子,结合医学知识,归纳为心理性亚健康、疲劳性亚健康、睡眠性亚健康、胃肠性亚健康、体质性亚健康、疼痛性亚健康和其他型亚健康7个亚健康亚型。结论亚健康人群在不同亚型下有不同症状特征。  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