全文获取类型
收费全文 | 2335898篇 |
免费 | 174963篇 |
国内免费 | 3279篇 |
学科分类
医药卫生 | 2514140篇 |
出版年
2021年 | 18302篇 |
2019年 | 19532篇 |
2018年 | 27048篇 |
2017年 | 20354篇 |
2016年 | 22743篇 |
2015年 | 25637篇 |
2014年 | 36094篇 |
2013年 | 53951篇 |
2012年 | 74674篇 |
2011年 | 79405篇 |
2010年 | 47055篇 |
2009年 | 44565篇 |
2008年 | 74607篇 |
2007年 | 79475篇 |
2006年 | 80294篇 |
2005年 | 77779篇 |
2004年 | 74366篇 |
2003年 | 71689篇 |
2002年 | 69362篇 |
2001年 | 108737篇 |
2000年 | 111450篇 |
1999年 | 93494篇 |
1998年 | 26990篇 |
1997年 | 23543篇 |
1996年 | 22354篇 |
1995年 | 22558篇 |
1994年 | 20763篇 |
1993年 | 19593篇 |
1992年 | 71871篇 |
1991年 | 70045篇 |
1990年 | 68347篇 |
1989年 | 65624篇 |
1988年 | 60245篇 |
1987年 | 59075篇 |
1986年 | 55181篇 |
1985年 | 52965篇 |
1984年 | 39235篇 |
1983年 | 33299篇 |
1982年 | 19758篇 |
1979年 | 35782篇 |
1978年 | 25577篇 |
1977年 | 21129篇 |
1976年 | 20254篇 |
1975年 | 21752篇 |
1974年 | 26089篇 |
1973年 | 24761篇 |
1972年 | 23179篇 |
1971年 | 22013篇 |
1970年 | 20220篇 |
1969年 | 19285篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Xiying Fan Glen A. Bjerke Kent Riemondy Li Wang Rui Yi 《Molecular carcinogenesis》2019,58(12):2241-2253
MicroRNAs (miRNAs) play important roles in prostate cancer development. However, it remains unclear how individual miRNAs contribute to the initiation and progression of prostate cancer. Here we show that a basal layer‐enriched miRNA is required for prostate tumorigenesis. We identify miR‐205 as the most highly expressed miRNA and enriched in the basal cells of the prostate. Although miR‐205 is not required for normal prostate development and homeostasis, genetic deletion of miR‐205 in a Pten null tumor model significantly compromises tumor progression and does not promote metastasis. In Pten null basal cells, loss of miR‐205 attenuates pAkt levels and promotes cellular senescence. Furthermore, although overexpression of miR‐205 in prostate cancer cells with luminal phenotypes inhibits cell growth in both human and mouse, miR‐205 has a minimal effect on the growth of a normal human prostate cell line. Taken together, we have provided genetic evidence for a requirement of miR‐205 in the progression of Pten null‐induced prostate cancer. 相似文献
32.
M.-A. Fauroux A. Germa P. Tramini C. Nabet 《Revue d'épidémiologie et de santé publique》2019,67(4):223-231
BackgroundThe aim of this study was to estimate the prevalence of dental prosthetic treatment and to investigate the demographic, social, economic and medical factors associated with the use of fixed and removable dentures in a representative sample of adults living in France.MethodsThe data were obtained from the 2002–2003 Decennial Health Survey, a cross-sectional study of a representative sample of the population living in France, which included 29,679 adults. Information was collected by interview. The variables collected were fixed denture, removable denture, age, gender, number of children, area of residence, nationality, educational attainment, family social status, employment status, annual household income per capita, supplementary insurance, chronic disease, eyesight problems/glasses, hearing problems/hearing aids. Multinomial logistic regression models were used to study the relationship between prosthetic treatment and demographic, socioeconomic and medical characteristics unadjusted, adjusted for age and adjusted for all the characteristics.ResultsThe prevalence of prosthetic treatment was 34.6% (95% confidence interval (CI): [34.1; 35.2]) for fixed prosthetic dentures and 13.8% (95% CI: [13.4; 14.2]) for removable prosthetic dentures. We showed a gradient between educational attainment and removable dentures; the odds ratio adjusted for all the variables (aOR) associated with no or primary education compared to post-secondary education was 2.56; 95% CI: [2.09; 3.13]. When annual household income per capita was low, subjects were less likely to report fixed dentures (aOR = 0.68; 95% CI: [0.62; 0.75]) than those with high annual household income per capita. Individuals without insurance less often reported fixed dentures than those with private insurance. Those reporting chronic disease were less likely to report fixed dentures (aOR = 0.87; 95% CI: [0.79; 0.95]) but more likely to report removable dentures (aOR = 1.29; 95% CI: [1.17; 1.43]) than those without chronic disease.ConclusionThis study reveals social, economic and medical inequalities in fixed and removable prosthetic treatment among adults in France. 相似文献
33.
34.
35.
36.
37.
Amy L. Judd Kathryn L. Beck Christopher McKinlay Ashleigh Jackson Cathryn A. Conlon 《Maternal & child nutrition》2020,16(1)
Dietary assessment in infants is challenging but necessary to understand the relationship between nutrition and growth and development. Currently no simple, validated methods exist to assess nutrient intake in New Zealand (NZ) infants. Therefore, this study aimed to assess the relative validity and reproducibility of a Complementary Food Frequency Questionnaire (CFFQ) to determine nutrient intakes of NZ infants. Ninety‐five parent–infant pairs (infant age 10 ± 1 months) completed the CFFQ twice (CFFQ‐1 and CFFQ‐2), 4 weeks apart (to assess reproducibility). A 4‐day weighed food record (4dWFR) was collected between CFFQ administrations (to assess validity). Validity and reproducibility were assessed for intakes of energy and 18 nutrients using Bland–Altman analysis, Pearson's correlation coefficients, cross‐classification, and weighted Kappa (κ). The CFFQ showed acceptable validity: Nutrients from the CFFQ were comparable with the 4dWFR (bias, 9–28%), correlation between methods ranged from r = .18 (saturated fat) to r = .81 (iron; mean r = .52), 54% (mean) of participants were correctly classified (range 39% to 67%), and 7.1% (mean) misclassified into opposite tertiles (range 2.1% to 14.7%). There was acceptable agreement between the CFFQ and 4dWFR (κ = 0.20–0.60). The CFFQ showed good reproducibility: Correlations ranged from r = .34 (folate) to r = .80 (zinc); for 16 nutrients, >50% of participants were correctly classified, and for all nutrients, <10% of participants were grossly misclassified. All nutrients showed acceptable to good agreement (κ > 0.20). The CFFQ has acceptable relative validity and good reproducibility for assessing nutrient intake in NZ infants aged 9–12 months, making it a useful tool for use in future research. 相似文献
38.
Widder Randolf A. Lappas Alexandra Rennings Corinna Hild Matthias Roessler Gernot F. Dietlein Thomas S. 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2020,258(11):2581-2581
Graefe's Archive for Clinical and Experimental Ophthalmology - The published online version contains mistake as the author's first name and last name have been interchanged as "Hild... 相似文献
39.
40.