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   65376篇
  免费   5535篇
  国内免费   2253篇
耳鼻咽喉   732篇
儿科学   1132篇
妇产科学   939篇
基础医学   7195篇
口腔科学   2383篇
临床医学   6330篇
内科学   12572篇
皮肤病学   1021篇
神经病学   4199篇
特种医学   1770篇
外国民族医学   10篇
外科学   7507篇
综合类   6710篇
现状与发展   12篇
一般理论   17篇
预防医学   5771篇
眼科学   1404篇
药学   6281篇
  56篇
中国医学   2991篇
肿瘤学   4132篇
  2024年   228篇
  2023年   873篇
  2022年   2359篇
  2021年   3310篇
  2020年   2251篇
  2019年   2142篇
  2018年   2381篇
  2017年   1998篇
  2016年   1910篇
  2015年   2573篇
  2014年   3202篇
  2013年   3697篇
  2012年   5271篇
  2011年   5652篇
  2010年   3544篇
  2009年   3055篇
  2008年   3993篇
  2007年   3815篇
  2006年   3492篇
  2005年   3106篇
  2004年   2568篇
  2003年   2285篇
  2002年   2028篇
  2001年   1080篇
  2000年   872篇
  1999年   746篇
  1998年   428篇
  1997年   350篇
  1996年   268篇
  1995年   249篇
  1994年   239篇
  1993年   190篇
  1992年   338篇
  1991年   301篇
  1990年   281篇
  1989年   200篇
  1988年   186篇
  1987年   157篇
  1986年   173篇
  1985年   151篇
  1984年   120篇
  1983年   87篇
  1982年   95篇
  1981年   78篇
  1980年   62篇
  1979年   104篇
  1978年   57篇
  1977年   62篇
  1975年   60篇
  1974年   71篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
目的 分析H型高血压患者的舌面诊图像颜色参数特征,探讨H型高血压患者的舌诊、面诊变化规律。方法 运用上海中医药大学自行研制的Smart TCM-1型中医舌面一体仪,采集高血压患者舌面诊图像,提取特征参数,分析健康对照组、H型高血压组与非H型高血压组患者舌面颜色参数特征。结果 ①在舌色各项参数中,H型高血压组舌尖部R值、B值、V值均显著小于健康对照组(P < 0.01);非H型高血压组舌尖部B值显著小于健康对照组(P < 0.01),S值较健康对照组显著增大(P < 0.05);H型高血压组舌尖部R、V值均明显小于非H型高血压组(P < 0.05)。在舌苔各项参数中,H型高血压组舌中H值、V值均明显小于健康对照组(P < 0.05);非H型高血压组舌中V值、舌右V值均显著小于健康对照组(P < 0.01);H型高血压组舌中H值明显小于非H型高血压组(P < 0.05),右侧舌苔S值明显大于非H型高血压组(P < 0.05)。②H型高血压组面色参数鼻G值、下颌G值、口唇R值、口唇V值均明显小于健康对照组(P < 0.05);非H型高血压组前额H值、目眶H值、脸颊H值、鼻H值、下颌H值、整体H值均明显大于健康对照组(P < 0.05);H型高血压组前额H值、目眶G值、目眶H值、脸颊H值、鼻G值、鼻H值、下颌R值、下颌G值、下颌H值、下颌V值、口唇R值、口唇G值、口唇V值、整体R值、整体G值、整体H值、整体V值均明显小于非H型高血压组(P < 0.05)。结论 H型高血压患者苔色偏黄,以舌中部为主,且舌右侧黄苔积聚较明显;H型高血压患者面色为黄中带红,口唇、下颌部更为晦暗。H型高血压患者的舌、面诊特征参数的变化,与高血压病阳亢湿盛病机相符。  相似文献   
42.
Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.  相似文献   
43.
Background: High-quality adverse drug reaction (ADR) reports are essential for conducting drug safety monitoring in pharmacovigilance. The study aim was to assess the current quality of ADR reports in western China, and to identify problems with ADR report quality.

Research design and methods: A sample of 1139 reports received by the Shaanxi ADR Monitoring Center from January 2015 to December 2017 was selected. ADR report quality was evaluated using an ADR report quality evaluation system.

Results: None of the reports were rated as excellent and 1.40% (n = 16) as good. Report quality was better for new and serious reports than for general reports. Medical institutions generated higher quality reports than pharmaceutical manufacturers. Nurses generated higher quality reports than doctors, pharmacists, and other professionals. Reporters of different occupations showed significant differences in the quality of the indicators Reporting time limit, Intervention ADR time, ADR termination time, ADR intervention measures, Original disease, and Cause of medication (P = 0.000).

Conclusions: The ADR data quality was poor in western China, and of lower quality than reported data from previous research in other regions. Improvements in the quality and availability of ADR reports are urgently needed.  相似文献   

44.
Studies on the exposure of children to sugar-sweetened beverages (SSBs) at an early age may contribute to better understand the common causes and the temporal order of the relationships between obesity and asthma in early childhood. The objective of this study was to estimate the association between SSB and child asthma traits in the 2nd year of life, modeling direct and indirect pathways mediated by the highest BMI-z of the child and allergic inflammation. Data from the BRISA cohort, São Luís-MA, Brazil (n = 1140), were obtained from the baseline and from the follow-up performed at the 2nd year of life. The main explanatory variable was the calories from added sugars in SSBs as a percentage of the total daily energy intake. The outcome child asthma traits was a latent variable deduced from four indicators: medical diagnosis of asthma, wheezing, emergency visit due to intense wheezing, and medical diagnosis of rhinitis. A high percentage of daily calories from sugars added to SSBs was directly associated with higher values of child asthma traits (standardized coefficient (SC = 0.073; P = .030)). High levels of eosinophils were also directly associated with child asthma traits (SC = 0.118; P = .049). No mediation pathways were observed via greater BMI-z or eosinophil counts. Therefore, early exposure of children to SSB may contribute to increased risk of childhood asthma, preceding the link between sugar consumption and overweight/obesity, not yet evident in children in the first 2 years of life.  相似文献   
45.
46.
47.
48.
49.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  相似文献   
50.
赵悦 《西南国防医药》2006,16(4):415-416
钩虫病是小肠寄生虫病,常与上消化道病变并存,常规胃镜检查时发现十二指肠钩虫具有偶然性。本文在行胃镜检查的14 850例中检出十二指肠钩虫45例。提示医师在常规胃镜检查过程中,对十二指肠尤其降部应仔细观察,一旦发现寄生虫应及时取出化验确诊。  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