全文获取类型
收费全文 | 452514篇 |
免费 | 31678篇 |
国内免费 | 7174篇 |
学科分类
医药卫生 | 491366篇 |
出版年
2021年 | 5757篇 |
2020年 | 4056篇 |
2019年 | 4924篇 |
2018年 | 6886篇 |
2017年 | 5696篇 |
2016年 | 5933篇 |
2015年 | 7651篇 |
2014年 | 10189篇 |
2013年 | 11821篇 |
2012年 | 16514篇 |
2011年 | 17096篇 |
2010年 | 10757篇 |
2009年 | 9747篇 |
2008年 | 14302篇 |
2007年 | 14866篇 |
2006年 | 14572篇 |
2005年 | 13099篇 |
2004年 | 11667篇 |
2003年 | 11405篇 |
2002年 | 10591篇 |
2001年 | 29796篇 |
2000年 | 30018篇 |
1999年 | 24791篇 |
1998年 | 5902篇 |
1997年 | 4915篇 |
1996年 | 4244篇 |
1995年 | 3999篇 |
1994年 | 3606篇 |
1993年 | 3168篇 |
1992年 | 16360篇 |
1991年 | 15112篇 |
1990年 | 14381篇 |
1989年 | 14155篇 |
1988年 | 12715篇 |
1987年 | 12198篇 |
1986年 | 11210篇 |
1985年 | 10391篇 |
1984年 | 6949篇 |
1983年 | 5625篇 |
1982年 | 2742篇 |
1979年 | 5489篇 |
1978年 | 3350篇 |
1977年 | 2965篇 |
1975年 | 2643篇 |
1974年 | 3066篇 |
1973年 | 2873篇 |
1972年 | 2832篇 |
1971年 | 2773篇 |
1970年 | 2511篇 |
1969年 | 2544篇 |
排序方式: 共有10000条查询结果,搜索用时 518 毫秒
71.
72.
73.
Parallel enzyme‐linked immunosorbent assay screening for human immunodeficiency virus among blood donors in five Chinese blood centres: a retrospective analysis 下载免费PDF全文
74.
75.
76.
77.
78.
Fei Xu Ming‐Liang Ye Yu‐Peng Zhang Wen‐Jie Li Meng‐Ting Li Hai‐Zhou Wang Xiao Qiu Yan Xu Jin‐Wen Yin Qian Hu Wan‐Hui Wei Ying Chang Lan Liu Qiu Zhao 《Cancer science》2020,111(5):1528-1541
Resistance to chemotherapy is a major challenge for the treatment of patients with colorectal cancer (CRC). Previous studies have found that microRNAs (miRNAs) play key roles in drug resistance; however, the role of miRNA‐373‐3p (miR‐375‐3p) in CRC remains unclear. The current study aimed to explore the potential function of miR‐375‐3p in 5‐fluorouracil (5‐FU) resistance. MicroRNA‐375‐3p was found to be widely downregulated in human CRC cell lines and tissues and to promote the sensitivity of CRC cells to 5‐FU by inducing colon cancer cell apoptosis and cycle arrest and by inhibiting cell growth, migration, and invasion in vitro. Thymidylate synthase (TYMS) was found to be a direct target of miR‐375‐3p, and TYMS knockdown exerted similar effects as miR‐375‐3p overexpression on the CRC cellular response to 5‐FU. Lipid‐coated calcium carbonate nanoparticles (NPs) were designed to cotransport 5‐FU and miR‐375‐3p into cells efficiently and rapidly and to release the drugs in a weakly acidic tumor microenvironment. The therapeutic effect of combined miR‐375 + 5‐FU/NPs was significantly higher than that of the individual treatments in mouse s.c. xenografts derived from HCT116 cells. Our results suggest that restoring miR‐375‐3p levels could be a future novel therapeutic strategy to enhance chemosensitivity to 5‐FU. 相似文献
79.
Harinakshi Sanikini David C. Muller Marisa Sophiea Sabina Rinaldi Antonio Agudo Eric J. Duell Elisabete Weiderpass Kim Overvad Anne Tjønneland Jytte Halkjær Marie-Christine Boutron-Ruault Franck Carbonnel Iris Cervenka Heiner Boeing Rudolf Kaaks Tilman Kühn Antonia Trichopoulou Georgia Martimianaki Anna Karakatsani Valeria Pala Domenico Palli Amalia Mattiello Rosario Tumino Carlotta Sacerdote Guri Skeie Charlotta Rylander María-Dolores Chirlaque López Maria-Jose Sánchez Eva Ardanaz Sara Regnér Tanja Stocks Bas Bueno-de-Mesquita Roel C.H. Vermeulen Dagfinn Aune Tammy Y.N. Tong Nathalie Kliemann Neil Murphy Marc Chadeau-Hyam Marc J. Gunter Amanda J. Cross 《International journal of cancer. Journal international du cancer》2020,146(4):929-942
Obesity has been associated with upper gastrointestinal cancers; however, there are limited prospective data on associations by subtype/subsite. Obesity can impact hormonal factors, which have been hypothesized to play a role in these cancers. We investigated anthropometric and reproductive factors in relation to esophageal and gastric cancer by subtype and subsite for 476,160 participants from the European Prospective Investigation into Cancer and Nutrition cohort. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox models. During a mean follow-up of 14 years, 220 esophageal adenocarcinomas (EA), 195 esophageal squamous cell carcinomas, 243 gastric cardia (GC) and 373 gastric noncardia (GNC) cancers were diagnosed. Body mass index (BMI) was associated with EA in men (BMI ≥30 vs. 18.5–25 kg/m2: HR = 1.94, 95% CI: 1.25–3.03) and women (HR = 2.66, 95% CI: 1.15–6.19); however, adjustment for waist-to-hip ratio (WHR) attenuated these associations. After mutual adjustment for BMI and HC, respectively, WHR and waist circumference (WC) were associated with EA in men (HR = 3.47, 95% CI: 1.99–6.06 for WHR >0.96 vs. <0.91; HR = 2.67, 95% CI: 1.52–4.72 for WC >98 vs. <90 cm) and women (HR = 4.40, 95% CI: 1.35–14.33 for WHR >0.82 vs. <0.76; HR = 5.67, 95% CI: 1.76–18.26 for WC >84 vs. <74 cm). WHR was also positively associated with GC in women, and WC was positively associated with GC in men. Inverse associations were observed between parity and EA (HR = 0.38, 95% CI: 0.14–0.99; >2 vs. 0) and age at first pregnancy and GNC (HR = 0.54, 95% CI: 0.32–0.91; >26 vs. <22 years); whereas bilateral ovariectomy was positively associated with GNC (HR = 1.87, 95% CI: 1.04–3.36). These findings support a role for hormonal pathways in upper gastrointestinal cancers. 相似文献
80.
Zhai Shuting Lin Shuang Lin Zhongjie Xu Junjie Ji Tong Chen Ke Wu Ke Liu Hui Ying Hanning Fei Weiqiang Wang Jin Fu Guoxiang Wang Yifan Hu Xiaotong Cai Xiujun 《Gastric cancer》2020,23(3):483-496
Gastric Cancer - Epigenetic aberrations of tumor suppressor genes (TSGs), particularly DNA methylation, are frequently involved in the pathogenesis of gastric cancer (GC). Through a methylome... 相似文献