全文获取类型
收费全文 | 2530196篇 |
免费 | 200824篇 |
国内免费 | 3827篇 |
专业分类
耳鼻咽喉 | 34550篇 |
儿科学 | 83943篇 |
妇产科学 | 72213篇 |
基础医学 | 366914篇 |
口腔科学 | 74451篇 |
临床医学 | 230827篇 |
内科学 | 487644篇 |
皮肤病学 | 55126篇 |
神经病学 | 204530篇 |
特种医学 | 98544篇 |
外国民族医学 | 713篇 |
外科学 | 373733篇 |
综合类 | 59377篇 |
现状与发展 | 5篇 |
一般理论 | 1060篇 |
预防医学 | 203780篇 |
眼科学 | 58125篇 |
药学 | 190068篇 |
8篇 | |
中国医学 | 4341篇 |
肿瘤学 | 134895篇 |
出版年
2018年 | 25220篇 |
2016年 | 21626篇 |
2015年 | 25063篇 |
2014年 | 34563篇 |
2013年 | 53076篇 |
2012年 | 71753篇 |
2011年 | 76238篇 |
2010年 | 44690篇 |
2009年 | 42897篇 |
2008年 | 72414篇 |
2007年 | 76926篇 |
2006年 | 77220篇 |
2005年 | 75196篇 |
2004年 | 73406篇 |
2003年 | 70255篇 |
2002年 | 68437篇 |
2001年 | 113685篇 |
2000年 | 116914篇 |
1999年 | 98874篇 |
1998年 | 26127篇 |
1997年 | 23657篇 |
1996年 | 23870篇 |
1995年 | 24558篇 |
1994年 | 22962篇 |
1993年 | 21636篇 |
1992年 | 81412篇 |
1991年 | 79607篇 |
1990年 | 77643篇 |
1989年 | 75198篇 |
1988年 | 69762篇 |
1987年 | 68678篇 |
1986年 | 65559篇 |
1985年 | 62945篇 |
1984年 | 47433篇 |
1983年 | 41303篇 |
1982年 | 24362篇 |
1981年 | 21942篇 |
1980年 | 20653篇 |
1979年 | 45368篇 |
1978年 | 32229篇 |
1977年 | 27091篇 |
1976年 | 25457篇 |
1975年 | 27083篇 |
1974年 | 33069篇 |
1973年 | 32142篇 |
1972年 | 29925篇 |
1971年 | 28076篇 |
1970年 | 26079篇 |
1969年 | 24711篇 |
1968年 | 22697篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Jayaraman Chandrasekaran Embry Kyle R. Mummidisetty Chaithanya K. Moon Yaejin Giffhorn Matt Prokup Sara Lim Bokman Lee Jusuk Lee Younbaek Lee Minhyung Jayaraman Arun 《Journal of neuroengineering and rehabilitation》2022,19(1):1-13
Numerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. Sixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. Statistical analysis used a linear mixed model to evaluate the effects on the center of pressure and the center of mass. The canes significantly reduced the variability of the center of pressure and the center of mass to the same level as when standing on the ground. Increasing the exerted force beyond the preferred level yielded no further benefits, although in the preferred force condition, participants exploited the altered mechanics by resting their arms on the canes. The tripod configuration allowed for larger variability of the center of pressure in the task-irrelevant anterior–posterior dimension. High forces had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. Given this static instability, these results show that using canes can provide not only mechanical benefits but also challenges. From a control perspective, effort can be reduced by resting the arms on the canes and by channeling noise in the task-irrelevant dimensions. However, larger forces exerted onto the canes can also have destabilizing effects and the instability of the canes needs to be counteracted, possibly by arm and shoulder stiffness. Insights into the variety of mechanical effects is important for the design of canes and the instructions of how to use them. 相似文献
2.
3.
4.
Alicia C. McDonald PhD MPH Jeremy Gernand PhD Nathaniel R. Geyer DrPH Hongke Wu MD MPH Yanxu Yang MPH Ming Wang PhD 《Cancer》2022,128(9):1832-1839
5.
6.
Clinical Oral Investigations - To evaluate the effect of membrane occlusiveness and experimental diabetes on early and late healing following guided bone regeneration. A total of 30 Wistar rats... 相似文献
7.
8.
9.
10.
Nanotherapy: New Approach for Impeding Hepatic Cancer Microenvironment via Targeting Multiple Molecular Pathways 下载免费PDF全文
Ahmed A Abd-Rabou Hanaa H Ahmed Safaa H MohamedSoheir E KotobMohamed S Kishta 《Asian Pacific journal of cancer prevention》2022,23(12):4261-4273
Objective: Hepatocellular carcinoma (HCC) microenvironment has been recognized as a key contributor for cancer progression, metastasis, and drug resistance. The crosstalk between tumor cells, the vascular endothelial growth factor (VEGF), and the chemokine (C-C motif) ligand 2 (CCL2) signaling networks mediates immunoinhibitory impact and facilitates tumor angiogenesis. The current investigation aimed at exploring the potent anti-cancer activity of the newly designed nano-based anti-cancer therapy comprising anti-VEGF drug, avastin (AV), and CCR2 antagonist (CR) to counteract HCC and tracking its mode of action in vivo. Methods: The prepared AV, CR, and AVCR nanoprototypes were characterized by nanoscale characterization techniques in our previous work. Here, they are applied for unearthing their anti-cancer properties / mechanisms in hepatic cancer-induced rats via analyzing protein levels and genetic expression of the elements incorporated in the angiogenesis, apoptosis, and metastasis signalling pathways. Results: The present results revealed a significant down-regulation in the angiogenesis, survival and metastasis indices along with up-regulation in the pro-apoptotic mediators upon treatment of hepatic cancer-bearing rats with the novel synthesized nanomaterials when compared with the untreated counterparts. We showed across HCC model that anti-VEGF in combination with CCR2 antagonism therapy leads to sensitization and enhanced tumor response over anti-VEGF or CCR2 antagonism monotherapy, particularly in its nanoscale formulation. Conclusion: The present approach provides new mechanistic insights into the powerful anti-hepatic cancer advantage of the novel nanoprototypes which is correlated with modulating critical signal transduction pathways implicated in tumor microenviroment such as angiogenesis, apoptosis and metastasis. This research work presents a substantial foundation for future studies focused on prohibiting cancer progression and recovery by targeting tumor microenviroment. 相似文献