全文获取类型
收费全文 | 181793篇 |
免费 | 15970篇 |
国内免费 | 11697篇 |
专业分类
耳鼻咽喉 | 1561篇 |
儿科学 | 1807篇 |
妇产科学 | 2425篇 |
基础医学 | 21846篇 |
口腔科学 | 2998篇 |
临床医学 | 25253篇 |
内科学 | 26901篇 |
皮肤病学 | 1807篇 |
神经病学 | 10240篇 |
特种医学 | 6663篇 |
外国民族医学 | 109篇 |
外科学 | 17992篇 |
综合类 | 28682篇 |
现状与发展 | 42篇 |
一般理论 | 12篇 |
预防医学 | 10621篇 |
眼科学 | 5494篇 |
药学 | 18392篇 |
196篇 | |
中国医学 | 10134篇 |
肿瘤学 | 16285篇 |
出版年
2025年 | 51篇 |
2024年 | 2492篇 |
2023年 | 3773篇 |
2022年 | 7682篇 |
2021年 | 9459篇 |
2020年 | 7479篇 |
2019年 | 6496篇 |
2018年 | 6449篇 |
2017年 | 5727篇 |
2016年 | 5424篇 |
2015年 | 8278篇 |
2014年 | 10062篇 |
2013年 | 8586篇 |
2012年 | 12874篇 |
2011年 | 14384篇 |
2010年 | 8480篇 |
2009年 | 6499篇 |
2008年 | 8910篇 |
2007年 | 8871篇 |
2006年 | 9047篇 |
2005年 | 9044篇 |
2004年 | 5571篇 |
2003年 | 5296篇 |
2002年 | 4355篇 |
2001年 | 3902篇 |
2000年 | 4259篇 |
1999年 | 4535篇 |
1998年 | 2810篇 |
1997年 | 2821篇 |
1996年 | 2247篇 |
1995年 | 2092篇 |
1994年 | 1734篇 |
1993年 | 1117篇 |
1992年 | 1518篇 |
1991年 | 1289篇 |
1990年 | 1035篇 |
1989年 | 884篇 |
1988年 | 810篇 |
1987年 | 717篇 |
1986年 | 589篇 |
1985年 | 420篇 |
1984年 | 274篇 |
1983年 | 197篇 |
1982年 | 117篇 |
1981年 | 113篇 |
1980年 | 87篇 |
1979年 | 111篇 |
1978年 | 42篇 |
1975年 | 48篇 |
1974年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Jie Wang Tao Jin Haifeng He Lei Liu 《Journal of biomaterials science. Polymer edition》2019,30(11):919-946
Cellulose is a kind of natural polymer material, which is composed of bundle-like fibrils. By peeling the fibrils layer by layer, the size of cellulose can be nanocrystallized, and nanofibers and nanocrystals with unique and potentially useful features can be prepared. As an emerging functional polymer material, nanocellulose has become a research hotspot in the field of technology. This review discusses the preparation of nanocellulose, including the commonly used hydrolysis, oxidation, physical and environmentally friendly ionic liquid methods. The advantages and disadvantages of different methods are also compared. And the review introduced the application of nanofiberized cellulose and nanocellulose crystals in the fields of thermosetting and thermoplastics, such as polylactic acid, polypropylene, epoxy resin and so on. The critical factors in the manufacturing of nanocellulose composites and mechanical properties are discussed to provide a reference for the further application and development of nanocellulose. 相似文献
42.
Liu Yixin Wei Wei Wang Yang Wan Chunyou Bai Yingyu Sun Xuguo Ma Jun Zheng Fang 《Inflammation research》2019,68(7):597-611
Inflammation Research - The present study was undertaken to validate whether TNF-α and calreticulin (CRT) serve as dual signaling to activate nucleotide-binding oligomerization domain-,... 相似文献
43.
44.
目的:分析中医辨证治疗高血压的效果.方法:随机抽取2015年3月~2016年9月128例高血压患者,分为对照组(n=64)与观察组(n=64),对照组予以西医的治疗方法,即服用常规的降血压药物;观察组予以中医辨证治疗的方法,即依据不同的症状服用不同的中药药剂,观察两组临床效果、治疗后的血压与不良反应.结果:观察组临床有效率为89.06%,明显高于对照组的70.31%(P<0.05);同时两组血压变化明显,并且两组均未出现不良反应.结论:采取中医辨证治疗高血压,可获得良好的治疗效果,提升康复率,值得临床推广. 相似文献
45.
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.46.
Although family-focused, evidence-based programs (EBPs) have the potential to reduce disparities in health and behavioral outcomes for youth, access to such programs is severely limited in the most affected areas, including African American communities in the rural South. As expanding the reach of EBPs is the primary goal of translational research, interest is growing in the potential of technology as a viable platform to disseminate services to areas with limited resources. To test whether African American families in the rural South would be willing to engage in a technology-based family-focused EBP to prevent adolescent risk behavior, we examined attendance using data from two arms of a three-arm community-based trial of the Pathways for African American Success (PAAS) program. In the overall study, sixth graders (N?=?412) and their primary caregivers were randomly assigned to the following conditions: (a) in-person, small group sessions led by facilitators; (b) self-directed, technology-based sessions; or (c) a literature control with home-mailed educational materials. Results indicated that attendance was higher in the technology condition than in the small group condition. Parental age, education, and socioeconomic status did not limit attendance in the technology condition. We conclude from these results that the use of technology can be an acceptable strategy for disseminating parenting EBPs to African American families in the rural South. 相似文献
47.
48.
Shu-xuan Liang Ling Ding Shigang Shen Wei Liu Jianbing Li Xiaocan Xi 《Bulletin of environmental contamination and toxicology》2018,100(2):250-258
This study assessed the level of Pb in soil and five wild plant species (Calotropis procera, Datura alba, Parthenium hysterophorus, Cenchrus ciliaris and Ricinus communis) during all the four seasons. Two busy roads varying in age and traffic volume were selected i.e., Faisalabad–Sargodha road (FSR) and Pindi Bhattian to Lillah (M-2) in the Punjab, Pakistan. Results showed raised levels of Pb in both plants and soil samples along both roads. The range of Pb concentration in plants was 0.08–3.98 and 1.95–4.74 mg kg??1 for soil. Higher Pb contamination was recorded along FSR road as compared to M-2. Among seasons, the higher Pb concentration was found during summer, probably due to very high temperature. Among all the plants studied, Calotropis procera accumulated the highest level (3.98 mg kg??1 dry wt.) of Pb; Thus, it can be used as good biomonitor/phytoremediator at Pb contaminated areas. 相似文献
49.
羟基磷灰石涂层—钛基牙种植体的动物植入实验 总被引:3,自引:0,他引:3
将56枚等离子喷涂羟基磷灰石涂层-钛基牙种植体植入狗股骨干。分别在术后1、2、3、4个月时制取不脱钙标本切片,作组织学观察、显微X线摄影及计算机辅助植体-骨接触率测量。 相似文献
50.
目的:研究羟基磷灰石人工骨(HAB)/异体脱矿骨粉(DBP)复合物修复骨缺损的效果,以期获得一种既具有传导性又具有骨诱导性的复合材料。方法:将HAB/DBP复合物、HAB、异体脱矿骨(DMB)植入兔桡骨中段骨缺损处,设置空白对照,在2、4、8、12周分别取材,观察新骨形成及骨缺损修复情况。结果:HAB/DBP组、DMB组2周时可见骨断端附近有大量软骨细胞聚集,并有少量基质形成。4周时,大量软骨细胞及少量骨小架。8周时,见大量骨小梁和层板状骨形成。12周见层板成熟骨组织和哈佛系统形成。其成骨能力及新骨生成量明显高于HAB组及空白组。结论:HAB/DBP复合物为一种既具有骨传导性又具有骨诱导性的骨缺损修复材料,具有与DMB同样的诱导骨生成的能力,可能成为一种具有临床应用前景的骨缺损及修复材料。 相似文献