全文获取类型
收费全文 | 1350455篇 |
免费 | 105391篇 |
国内免费 | 6284篇 |
专业分类
耳鼻咽喉 | 16808篇 |
儿科学 | 43073篇 |
妇产科学 | 36587篇 |
基础医学 | 184059篇 |
口腔科学 | 36360篇 |
临床医学 | 121171篇 |
内科学 | 279490篇 |
皮肤病学 | 31951篇 |
神经病学 | 111016篇 |
特种医学 | 55622篇 |
外国民族医学 | 274篇 |
外科学 | 210752篇 |
综合类 | 31575篇 |
现状与发展 | 2篇 |
一般理论 | 414篇 |
预防医学 | 106928篇 |
眼科学 | 28181篇 |
药学 | 94442篇 |
26篇 | |
中国医学 | 2235篇 |
肿瘤学 | 71164篇 |
出版年
2018年 | 13456篇 |
2017年 | 10703篇 |
2016年 | 12861篇 |
2015年 | 14348篇 |
2014年 | 19983篇 |
2013年 | 29788篇 |
2012年 | 36332篇 |
2011年 | 38955篇 |
2010年 | 24423篇 |
2009年 | 23972篇 |
2008年 | 36452篇 |
2007年 | 38849篇 |
2006年 | 39971篇 |
2005年 | 38567篇 |
2004年 | 36811篇 |
2003年 | 35891篇 |
2002年 | 33895篇 |
2001年 | 66118篇 |
2000年 | 67967篇 |
1999年 | 56641篇 |
1998年 | 16744篇 |
1997年 | 15043篇 |
1996年 | 16032篇 |
1995年 | 16253篇 |
1994年 | 15110篇 |
1993年 | 14167篇 |
1992年 | 47141篇 |
1991年 | 45786篇 |
1990年 | 44009篇 |
1989年 | 41855篇 |
1988年 | 38797篇 |
1987年 | 38105篇 |
1986年 | 35888篇 |
1985年 | 34669篇 |
1984年 | 26386篇 |
1983年 | 22139篇 |
1982年 | 13866篇 |
1981年 | 12453篇 |
1980年 | 11732篇 |
1979年 | 23568篇 |
1978年 | 17094篇 |
1977年 | 14394篇 |
1976年 | 13194篇 |
1975年 | 13741篇 |
1974年 | 16106篇 |
1973年 | 15410篇 |
1972年 | 14187篇 |
1971年 | 13048篇 |
1970年 | 11891篇 |
1969年 | 11110篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Wei-Guang Zhang Linpei Jia J. Ma S.-Y. Zhu S.-S. Nie K.-K. Song X.-M. Liu Y.-P. Zhang D. Cao X.-P. Yang D.-L. Zhao M.-J. Xiu L. Lin Z.-X. Li Q. Huang X.-Z. Chen L. Chen P. Wang X.-J. Bai Z. Feng B. Fu J. Huang J.-P. Zhang Guangyan Cai X.-F. Sun Xiangmei Chen 《The journal of nutrition, health & aging》2018,22(2):276-281
Objectives
We aimed to evaluate the relationship between baseline renal function and changes in telomere length in Han Chinese.Methods
The telomere restriction fragment (TRF) length of leukocytes in the peripheral blood was measured in healthy volunteers recruited in 2014. The estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine (Scr) and serum cystatin C (CysC)-eGFRcys and eGFRScr-cys through the Cockcroft-Gault formula (eGFRC-G) or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI / eGFRCKD-EPI) equation. The correlation between telomere length changes over time and renal function was analyzed.Results
Leukocyte TRF lengths were negatively correlated to age (r = -0.393, p < 0.001) and serum CysC (r = -0.180, p < 0.01), while positively associated with eGFRCKD-EPI, eGFRC-G, eGFRcys, and eGFRScr-cys (r = 0.182, 0.122, 0.290, and 0.254 respectively, p < 0.01). The 3-year change of telomere length was 46 bp/years. When adjusted for age, the associations between telomere length changes and baseline, subsequent TRF lengths, and serum CysC were no longer present. No association was observed between TRF length changes and renal function.Conclusion
The rate of telomere length changes was affected by age and baseline telomere length. The telomere length changes might be important markers for aging.93.
94.
Ryan C. Lewis John D. Meeker Niladri Basu Alison M. Gauthier Alejandra Cantoral Adriana Mercado-García Karen E. Peterson Martha Maria Téllez-Rojo Deborah J. Watkins 《International journal of hygiene and environmental health》2018,221(4):609-615
Personal care product use is a potential source of metals exposure among children, but studies have been limited. We measured urinary concentrations of 10 metals (aluminum, arsenic [As], barium [Ba], cadmium, cobalt [Co], lead [Pb], manganese [Mn], molybdenum [Mo], nickel, and zinc [Zn]) in third trimester pregnant women (n?=?212) and their children at 8–14 years of age (n?=?250). Demographic factors (child sex, age, socioeconomic status, and maternal education), body mass index (BMI) z-score, and child personal care product use in the 24?h prior to urine collection were examined as predictors of urinary metal concentrations. Metals were detected in 80–100% of urine samples, with significant differences in maternal versus childhood levels. However, metal concentrations were not strongly correlated within or between time points. In linear regression models including all demographic characteristics, BMI z-score, and specific gravity, age was associated with higher Co (6% [95% CI: 2, 10]), while BMI z-score was associated with lower Mo (-6% [95% CI: -11, -1). In addition, significantly higher metal concentrations were observed among users of colored cosmetics (Mo: 42% [95% CI: 1, 99]), deodorant (Ba: 28% [3, 58]), hair spray/hair gel (Mn: 22% [3, 45]), and other toiletries (As: 50% [9, 108]), as well as with an increasing number of personal care products used (As: 7% [3, 11]) after adjustment for child sex, age, total number of products used, and specific gravity. However, significantly lower metal concentrations were noted for users of hair cream (As and Zn: -20% [-36, -2] and -21% [-35, -2], respectively), shampoo (Pb: -40% [-62, -7]), and other hair products (Pb: -44% [-65, -9]). We found that personal care product use may be a predictor of exposure to multiple metals among children. Further research is recommended to inform product-specific exposure source identification and related child health risk assessment efforts. 相似文献
95.
96.
97.
98.
99.
Rayssa de Lima Cardoso Raimunda Nonata Fortes Carvalho-Neta Antonio Carlos Leal de Castro Cássia Fernanda Chagas Ferreira Marcelo Henrique Lopes Silva James Werllen de Jesus Azevedo João Reis Salgado Costa Sobrinho Débora Martins Silva Santos 《Bulletin of environmental contamination and toxicology》2018,101(5):570-579
The quality of aquatic environments all around the world is being altered by different human activities that represent direct threat to the ecological system and the aquatic biota. This study aimed to evaluate the occurrence of histological and genotoxic alterations in Prochilodus lacustris as indicators of anthropic impacts in a lacustrine environment in northeast Brazil. The histological alterations were evaluated using the histological alteration index, and the genotoxic alterations were detected using the micronuclei test, at three sampling stations (S1, S2 and S3). The gills presented lesions with three stages of severity, with mild lesions more frequent in the specimens collected at station S1. Mild hepatic tissue lesions were the most frequent type in both areas. Micronucleus analysis showed that station S3 was the most affected. The biological responses observed indicated that the fish are under influence of environmental changes. It is important to highlight that the organisms collected at station S3 had a more compromised health status. 相似文献
100.