全文获取类型
收费全文 | 2079篇 |
免费 | 98篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 29篇 |
儿科学 | 39篇 |
妇产科学 | 82篇 |
基础医学 | 362篇 |
口腔科学 | 14篇 |
临床医学 | 204篇 |
内科学 | 398篇 |
皮肤病学 | 19篇 |
神经病学 | 201篇 |
特种医学 | 80篇 |
外科学 | 362篇 |
综合类 | 8篇 |
预防医学 | 108篇 |
眼科学 | 45篇 |
药学 | 113篇 |
中国医学 | 19篇 |
肿瘤学 | 106篇 |
出版年
2022年 | 13篇 |
2021年 | 49篇 |
2020年 | 24篇 |
2019年 | 36篇 |
2018年 | 52篇 |
2017年 | 33篇 |
2016年 | 26篇 |
2015年 | 59篇 |
2014年 | 60篇 |
2013年 | 73篇 |
2012年 | 121篇 |
2011年 | 125篇 |
2010年 | 49篇 |
2009年 | 47篇 |
2008年 | 98篇 |
2007年 | 103篇 |
2006年 | 116篇 |
2005年 | 112篇 |
2004年 | 105篇 |
2003年 | 103篇 |
2002年 | 99篇 |
2001年 | 47篇 |
2000年 | 48篇 |
1999年 | 39篇 |
1998年 | 20篇 |
1997年 | 14篇 |
1996年 | 16篇 |
1995年 | 18篇 |
1992年 | 28篇 |
1991年 | 38篇 |
1990年 | 27篇 |
1989年 | 32篇 |
1988年 | 35篇 |
1987年 | 35篇 |
1986年 | 21篇 |
1985年 | 37篇 |
1984年 | 21篇 |
1983年 | 24篇 |
1982年 | 10篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 31篇 |
1977年 | 8篇 |
1975年 | 7篇 |
1974年 | 11篇 |
1973年 | 8篇 |
1972年 | 14篇 |
1970年 | 8篇 |
1969年 | 9篇 |
1968年 | 9篇 |
排序方式: 共有2189条查询结果,搜索用时 281 毫秒
71.
72.
73.
74.
Selection of cases with additional affected relatives has been shown to increase the power of the case-control association
design. We investigated whether this strategy can also improve the power of family-based association studies that use the
transmission disequilibrium test (TDT), while accounting for the effects of residual polygenic and environmental factors on
disease liability. Ascertainment of parent-offspring trios conditional on the proband having affected first-degree relatives
almost always reduced the power of the TDT. For many disease models, this reduction was quite considerable. In contrast, for
the same sample size, designs that analyzed more than one affected offspring per family often improved power when compared
to the standard parent-offspring trio design. Together, our results suggest that (1) residual polygenic and environmental
influences should be considered when estimating the power of the TDT for studies that ascertain families with multiple affected
relatives; (2) if trios are selected conditional on having additional affected offspring, then it is important to genotype
and include in the analysis the additional siblings; (3) the ascertainment strategy should be considered when interpreting
results from TDT analyses. Our analytic approach to estimate the asymptotic power of the TDT is implemented online at http://pngu.mgh.harvard.edu/∼purcell/gpc/.
Edited by David Allison 相似文献
75.
Xanthohumol ameliorates 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin–induced cellular toxicity in cultured MC3T3‐E1 osteoblastic cells 下载免费PDF全文
Hyun‐Sook Kim So Young Park Sang Ouk Chin Sang Youl Rhee Youngmi Kim Pak Wonchae Choe Joohun Ha Suk Chon 《Journal of applied toxicology : JAT》2018,38(7):1036-1046
2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) is an environmental contaminant. Xanthohumol is a prenylated flavonoid found in hops (Humulus lupulus) and beer. The aim of the current study was to explore the role of xanthohumol in modulating the toxicity of TCDD in MC3T3‐E1 osteoblastic cells. In cells treated with TCDD alone, intracellular Ca2+ concentrations, mitochondrial membrane potential disruption, reactive oxygen species production, cardiolipin peroxidation, nitric oxide release and cytochrome P450 1A1 expression were significantly increased. TCDD treatment increased the mRNA levels of extracellular signal‐regulated kinase 1 and nuclear factor kappa B, and significantly decreased the level of protein kinase B (AKT) in MC3T3‐E1 osteoblastic cells. However, the presence of xanthohumol alleviated the pathological effects of TCDD. In addition, xanthohumol treatment significantly increased the expression of genes associated with osteoblast differentiation (alkaline phosphatase, osteocalcin, osteoprotegerin and osterix). We conclude that xanthohumol has a beneficial influence and may antagonize TCDD toxicity in osteoblastic cells. 相似文献
76.
Ho Young Kim Ju Young Kim Hwa Yeon Park Ji Hye Jun Hye Yeon Koo In Young Cho Jinah Han Yuliya Pak Hyun Jung Baek Ju Yeon Lee Sung Hee Chang Jung Hun Lee Ji Soo Choe Sun-kyung Yang Kyung Chul Kim Jeong Ha Park Seul Ki Paik 《Globalization and health》2018,14(1):120
Background
With the significant growth of migration and expatriation, facilitated by increased global mobility, the number of Koreans living abroad as of 2016 is approximately 7.4 million (15% of the Korean population). Healthcare utilization or health problems, especially among expatriates in developing countries, have not been well researched despite the various health risks these individuals are exposed to. Consequently, we identified the health utilization patterns and healthcare needs among Korean expatriates in Vietnam, Cambodia, and Uzbekistan.Methods
This cross-sectional survey examined 429 Korean expatriates living in Vietnam (n?=?208), Cambodia (n?=?60), and Uzbekistan (n?=?161) who had access to the Internet and were living abroad for at least 6?months. A 67-item questionnaire was used, and feedback was received via an online survey program. Stepwise logistic regression analyses were performed to evaluate factors associated with unmet healthcare needs and preferences of certain type of telemedicine.Results
We found that 45.5% (195/429) of respondents had used medical services in their country of stay. Among those who visited health institutions >?3 times, the most popular choice was general hospitals (39.4%, 15/38); however, they initially visited Korean doctors’ or local doctors’ offices. The most essential criteria for healthcare service facilities was a “skilled professional” (39.3%, 169/429), 42% wanted a health program for chronic disease management, and 30% wanted specialized internal medicine. A substantial number wanted to access telemedicine services and were willing to pay for this service. They were particularly interested in experts’ second opinion (61.5%, 264/429) and quick, 24-h medical consultations (60.8%, 261/429). Having unmet healthcare needs and being younger was strongly associated with all types of telemedicine networks.Conclusions
Nearly half of the expatriates in developing countries had unmet healthcare needs. Telemedicine is one potential solution to meet these needs, especially in developing countries.77.
78.
79.
80.
This paper demonstrates the enhanced NO2 sensing performance of graphene with defects generated by rapid thermal annealing (RTA). A high temperature of RTA (300–700 °C) was applied to graphene under an argon atmosphere to form defects on sp2 carbon lattices. The density of defects proportionally increased with increasing the RTA temperature. Raman scattering results confirmed significant changes in sp2 bonding. After 700 °C RTA, ID/IG, I2D/IG, and FWHM (full width at half maximum)(G) values, which are used to indirectly investigate carbon-carbon bonds’ chemical and physical properties, were markedly changed compared to the pristine graphene. Further evidence of the thermally-induced defects on graphene was found via electrical resistance measurements. The electrical resistance of the RTA-treated graphene linearly increased with increasing RTA temperature. Meanwhile, the NO2 response of graphene sensors increased from 0 to 500 °C and reached maximum (R = ~24%) at 500 °C. Then, the response rather decreased at 700 °C (R = ~14%). The results imply that rich defects formed at above a critical temperature (~500 °C) may damage electrical paths of sp2 chains and thus deteriorate NO2 response. Compared to the existing functionalization process, the RTA treatment is very facile and allows precise control of the NO2 sensing characteristics, contributing to manufacturing commercial low-cost, high-performance, integrated sensors. 相似文献