全文获取类型
收费全文 | 325篇 |
免费 | 21篇 |
国内免费 | 3篇 |
专业分类
儿科学 | 5篇 |
妇产科学 | 10篇 |
基础医学 | 59篇 |
口腔科学 | 17篇 |
临床医学 | 24篇 |
内科学 | 60篇 |
皮肤病学 | 4篇 |
神经病学 | 22篇 |
特种医学 | 6篇 |
外科学 | 27篇 |
综合类 | 14篇 |
预防医学 | 46篇 |
眼科学 | 2篇 |
药学 | 18篇 |
1篇 | |
中国医学 | 2篇 |
肿瘤学 | 32篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 32篇 |
2020年 | 14篇 |
2019年 | 21篇 |
2018年 | 25篇 |
2017年 | 11篇 |
2016年 | 14篇 |
2015年 | 18篇 |
2014年 | 11篇 |
2013年 | 15篇 |
2012年 | 29篇 |
2011年 | 20篇 |
2010年 | 16篇 |
2009年 | 12篇 |
2008年 | 16篇 |
2007年 | 11篇 |
2006年 | 17篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1970年 | 3篇 |
1966年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有349条查询结果,搜索用时 15 毫秒
1.
2.
Alex M. Hollenberg Noorullah Maqsoodi Amy Phan Aric Huber Ayodeji Jubril Avionna L. Baldwin Noriaki Yokogawa Roman A. Eliseev Addisu Mesfin 《The spine journal》2021,21(7):1205-1216
BACKGROUND CONTEXTBack and neck pain secondary to disc degeneration is a major public health burden. There is a need for therapeutic treatments to restore intervertebral disc (IVD) composition and function.PURPOSETo quantify ALK3, BMP-2, pSMAD1/5/8 and MMP-13 expression in IVD specimens collected from patients undergoing surgery for disc degeneration, to correlate ALK3, BMP-2, pSMAD1/5/8 and MMP-13 expression in IVD specimens to the 5-level Pfirrmann MRI grading system, and to compare ALK3, BMP-2, pSMAD1/5/8 and MMP-13 expression between cervical and lumbar degenerative disc specimens.STUDY DESIGNAn immunohistochemical study assessing ALK3, BMP-2, pSMAD1/5/8, and MMP-13 expression levels in human control and degenerative IVD specimens.METHODSHuman IVD specimens were collected from surgical patients who underwent discectomy and interbody fusion at our institution between 1/2015 and 8/2017. Each patient underwent MRI prior to surgery. The degree of disc degeneration was measured according to the 5-level Pfirrmann MRI grading system. Patients were categorized into either the 1) control group (Pfirrmann grades I-II) or 2) degenerative group (Pfirrmann grades III-V). Histology slides of the collected IVD specimens were prepared and immunohistochemical staining was performed to assess ALK3, BMP-2, pSMAD1/5/8, and MMP-13 expression levels in the control and degenerative specimens. Expression levels were also correlated to the Pfirrmann criteria. Lastly, the degenerative specimens were stratified according to their vertebral level and expression levels between the degenerative lumbar and cervical discs were compared.RESULTSFifty-two patients were enrolled; however, 2 control and 2 degenerative patients were excluded due to incomplete data sets. Of the remaining 48 patients, there were 12 control and 36 degenerative specimens. Degenerative specimens had increased expression levels of BMP-2 (p=.0006) and pSMAD1/5/8 (p<.0001). Pfirrmann grade 3 (p=.0365) and grade 4 (p=.0008) discs had significantly higher BMP-2 expression as compared to grade 2 discs. Pfirrmann grade 4 discs had higher pSMAD1/5/8 expression as compared to grade 2 discs (p<.0001). There were no differences in ALK3 or MMP-13 expression between the control and degenerative discs (p>.05). Stratifying the degenerative specimens according to their vertebral level showed no significant differences in expression levels between the lumbar and cervical discs (p>.05).CONCLUSIONSBMP-2 and pSMAD1/5/8 signaling activity was significantly upregulated in the human degenerative specimens, while ALK3 and MMP-13 expression were not significantly changed. The expression levels of BMP-2 and pSMAD1/5/8 correlate positively with the degree of disc degeneration measured according to the Pfirrmann MRI grading system.CLINICAL SIGNIFICANCEBMP-SMAD signaling represents a promising therapeutic target to restore IVD composition and function in the setting of disc degeneration. 相似文献
3.
Alexandra E Connelly Jessie Satia-Abouta Christopher F Martin Temitope O Keku John T Woosley P Kay Lund Robert S Sandler 《Cancer epidemiology, biomarkers & prevention》2003,12(6):559-565
Apoptosis, or programmed cell death, may lower the risk of neoplasia by removing genetically damaged or mutated cells. A high rate of apoptosis has been linked to a reduced risk of colorectal adenomas; therefore, it is important to understand factors that impact apoptosis. Antioxidants (e.g., vitamin C) protect cells from harmful oxidation processes but may interfere with apoptosis by protecting genetically damaged cells from reactive oxygen species-dependent cell death. The objective of this study was to evaluate the association between vitamin C intake and apoptosis in normal rectal mucosa. Study participants were part of a large, cross-sectional study, the Diet and Health Study III. Participants were recruited from consecutive, consenting patients who underwent colonoscopy at University of North Carolina Hospitals between August 1, 1998 and March 4, 2000. Vitamin C intake, obtained from a food frequency questionnaire, included both dietary sources and vitamin supplements. Apoptosis was measured by morphological evaluation of H&E-stained sections obtained from pinch biopsy samples of normal rectal mucosa in consenting participants (n = 503). The relationship between vitamin C and apoptosis varied by adenoma status. Among individuals with adenomas, there was an inverse linear association between apoptosis and total vitamin C intake. Similarly, individuals with adenomas in the highest quintile of total vitamin C intake were substantially less likely than those in the lowest quintile to have increased colonic apoptosis (odds ratio, 0.05; 95% confidence interval, 0.01-0.46). Vitamin C was not significantly associated with apoptosis in adenoma-free patients. High vitamin C intake was associated with reduced colorectal apoptosis among individuals with adenomas in this study population. Given that high apoptosis may lower colorectal cancer risk, vitamin C supplements may be contraindicated for patients with a history of adenomas. 相似文献
4.
Metabolic Brain Disease - Parkinson’s disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta. The conventional therapeutic... 相似文献
5.
Adedotun Ogunbajo Temitope Oke Harry Jin William Rashidi Stella Iwuagwu Gary W. Harper 《AIDS care》2020,32(3):337-342
ABSTRACTNigerian gay, bisexual and other men who have sex with men (GBMSM) experience negative psychosocial health problems, which may increase their risk for HIV infection. Few studies have explored the syndemic effect of co-occurring psychosocial health problems on HIV sexual risk among Nigerian GBMSM. We investigated the co-occurrence of syndemic psychosocial health problems and their synergistic effect on HIV risk behaviors. We assessed depressive symptoms, post-traumatic stress disorder, alcohol dependence, tobacco use, and hard-drug use. The outcome variables were the number of male sexual partners and consistent condom use. In a multivariable model, experiencing 4 or more psychosocial health problems – compared to experience none or one psychosocial health problem – was significantly associated with increasing number of male sexual partners. We found no statistically significant association between the number of syndemic psychosocial health problems and consistent condom use. Our study findings provides evidence of a synergistic relationship between negative psychosocial health factors and HIV sexual risk behavior. These findings underscore the importance of developing HIV prevention programming aimed at reducing HIV transmission risk that incorporate substance use and mental health treatments, in order to improve the overall health and quality of life for Nigerian GBMSM. 相似文献
6.
Peggy Mulongo Sue McAndrew Eunice Ayodeji 《International journal of mental health nursing》2021,30(1):235-248
Globally, the exodus of individuals who have been forced to flee their home and seek refuge in countries of safety has led to a refugee crisis. The United Kingdom (UK) has engaged with the United Nations High Commissioner for Refugees (UNHCR) in playing a significant role in the long‐term resettlement of refugees, half of whom are children and young people. One initiative of such humanitarian resettlement is the Gateway Protection Programme (GPP). To date, there is a dearth of studies investigating aspects of acculturation that affect the mental health of young refugees resettled under the UNHCR humanitarian programme. This study aimed to explore aspects of acculturation that could enhance the mental health of GPP young refugees several years after resettlement. Using narrative research, a purposive sample of 31 GPP young refugees, who had a minimum of three‐year stay in the UK, were recruited from local refugee community organizations. Data were collected through a multi‐method design combining focus group discussions (FGDs) with visual arts‐based narrative research (VABNR) and analysed thematically. Three overarching themes emerged: People and places; Its nearly all new to me; and Finding self. This study contributes important knowledge regarding the mental well‐being of young people who have engaged in a resettlement programme and offers valuable information for policymakers and mental health professionals working with GPP young refugees. 相似文献
7.
8.
Olaposi I. Omotuyi Oyekanmi Nash David Safronetz Ayodeji A. Ojo Tomisin H. Ogunwa Niyi S. Adelakun 《Chemical biology & drug design》2019,93(4):544-555
Lassa virus infection is clinically characterized by multiorgan failure in humans. Without an FDA‐approved vaccine, ribavirin is the frontline drug for the treatment but with attendant toxicities. 6‐Fluoro‐3‐hydroxy‐2‐pyrazinecarboxamide (T‐705) is an emerging alternative drug with proven anti‐Lassa virus activity in experimental model. One of the mechanisms of action is its incorporation into nascent single‐strand RNA (ssRNA) which forms complex with Lassa nucleoprotein (LASV‐NP). Here, using molecular dynamics simulation, the structural and electrostatics changes associated with LASV‐NP‐ssRNA complex have been studied when none, one, or four of its bases has been substituted with T‐705. The results demonstrated that glycosidic torsion angle χ (O4′‐C1′‐N1‐C2) rotated from high‐anti‐ (?110° and ?60°) to the syn‐ conformation (+30) with increased T‐705 substitution. Similarly, increased T‐705 substitution resulted in increased splaying (55°–70°), loss of ssRNA‐LASV‐NP H‐bond interaction, increased water influx into the ssRNA‐binding pocket, and decreased electrostatic potentials of ssRNA pocket. Furthermore, strong positively correlated motion observed between α6 residues (aa: 128–145) and its contact ssRNA bases (5–7) is weakened in Apo biosystem and transitioned into anticorrelated motions in ssRNA‐bound LASV‐NP biosystem. Finally, LASV genome may become more accessible to cellular ribonuclease access with T‐705 incorporation due to loss of NP interaction. 相似文献
9.
Jindong Wang Wenzhi Li Huizhen Wang Ajibola Temitope Ogunbiyi Xiaomeng Dou Qiaozhi Ma 《RSC advances》2020,10(14):8558
To improve the utilization of lignin, much effort has been devoted to lignin depolymerization with the aim to decrease waste and enhance profitability. Here, a dual property (acid and base) catalyst, namely S2O82−–K2O/TiO2, was carefully researched. Upon loading S2O82− and K2O onto TiO2, acid and base sites emerged, and S2O82− and K2O mutually enhanced the acid and base strengths of the catalyst enormously; this indeed facilitated lignin depolymerization. Under appropriate conditions, the yields of liquid product, petroleum ether soluble (PE-soluble) product and total monomer products were 83.76%, 50.4% and 28.96%, respectively. The constituents of the PE-soluble fraction, which are mainly monomers and dimers, can be used as liquid fuels or additives. In addition, after the catalyst was modified by Ni, better results were obtained. Surprisingly, it was found that the Ni enhanced not only the hydrogenation capacity but also the acidity. The highest high heating value (HHV) of the liquid product (33.6 MJ kg−1) was obtained, and the yield of PE-soluble product increased from 50.4 to 56.4%. The product can be utilized as a fuel additive or be converted to bio-fuel. This catalysis system has significant potential in the conversion of lignin to bio-fuel.To improve the utilization of lignin, much effort has been devoted to lignin depolymerization with the aim to decrease waste and enhance profitability. 相似文献
10.
Brian J. Doyle Temitope O. Lawal Tracie D. Locklear Lorraina Hernandez Alice L. Perez Udeshi Patel 《Pharmaceutical biology》2018,56(1):235-244
Context: Pimenta dioica (L.) Merr. (Myrtaceae) is used in Costa Rican traditional medicine for women’s health. Our previous work showed that P. dioica extracts were oestrogenic.Objectives: This work identifies phytochemicals from P. dioica that are responsible for the plant’s oestrogen-like activities.Materials and methods: P. dioica leaves were collected in Costa Rica in 2005. Fractions resulting from chromatographic separation of a methanol extract were tested at 50?μg/mL in a competitive oestrogen receptor-binding assay. Active compounds were isolated by HPLC and identified by NMR and MS. Pure compounds were tested at 1?μM in the oestrogen-responsive SEAP reporter gene assay. The effects on cell viability, cytotoxicity and apoptosis were investigated in breast cancer (MCF-7 and SK-BR3) and gastric cancer (AGS and NCI-N87) cell lines using the ApoTox-Glo and Caspase-Glo assays and qPCR.Results: Quercitrin and three new chromones, including a 2-phenoxychromone, 6,8-di-C-methylcapillarisin (1) were isolated and identified. Compound 1 caused a 6.2-fold increase in SEAP expression at 1?μM (p?0.05). This activity was blocked by the ER antagonist ICI 182,780. Compound 2 caused a 6.0-fold increase in SEAP, inhibited the growth of MCF-7, AGS and NCI-N87 cells (IC50 54.27, 38.13 and 51.22?μg/mL, respectively), and induced apoptosis via caspase 8 and increased the Bax/Bcl-2 mRNA ratio in MCF-7 cells. Compound 3 was anti-oestrogenic in MCF-7 cells.Discussion and conclusions: Compounds from P. dioica have oestrogenic, anti-oestrogenic and cytotoxic effects that may explain the ethnomedical use of this plant. 相似文献