全文获取类型
收费全文 | 1148篇 |
免费 | 75篇 |
国内免费 | 3篇 |
专业分类
儿科学 | 30篇 |
妇产科学 | 43篇 |
基础医学 | 157篇 |
口腔科学 | 3篇 |
临床医学 | 153篇 |
内科学 | 146篇 |
皮肤病学 | 32篇 |
神经病学 | 148篇 |
特种医学 | 39篇 |
外科学 | 121篇 |
综合类 | 17篇 |
一般理论 | 1篇 |
预防医学 | 143篇 |
眼科学 | 7篇 |
药学 | 78篇 |
肿瘤学 | 108篇 |
出版年
2023年 | 11篇 |
2022年 | 13篇 |
2021年 | 34篇 |
2020年 | 17篇 |
2019年 | 43篇 |
2018年 | 35篇 |
2017年 | 31篇 |
2016年 | 22篇 |
2015年 | 32篇 |
2014年 | 42篇 |
2013年 | 55篇 |
2012年 | 116篇 |
2011年 | 92篇 |
2010年 | 58篇 |
2009年 | 34篇 |
2008年 | 74篇 |
2007年 | 98篇 |
2006年 | 71篇 |
2005年 | 60篇 |
2004年 | 59篇 |
2003年 | 56篇 |
2002年 | 38篇 |
2001年 | 10篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 5篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 9篇 |
1970年 | 2篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1944年 | 2篇 |
1933年 | 2篇 |
1920年 | 2篇 |
排序方式: 共有1226条查询结果,搜索用时 15 毫秒
61.
Rebecca L. Scalzo Hunter L. Paris Scott E. Binns Janelle L. Davis Joseph W. Beals Christopher L. Melby Gary J. Luckasen Matthew S. Hickey Benjamin F. Miller Karyn L. Hamilton Christopher Bell 《Clinical and experimental pharmacology & physiology》2017,44(7):729-738
Metformin augments glucose/glycogen regulation and may acutely promote fatigue resistance during high‐intensity exercise. In hypobaric environments, such as high altitude, the important contribution of carbohydrates to physiological function is accentuated as glucose/glycogen dependence is increased. Because hypoxia/hypobaria decreases insulin sensitivity, replenishing skeletal muscle glycogen in high altitude becomes challenging and subsequent physical performance may be compromised. We hypothesized that in conditions where glycogen repletion was critical to physical outcomes, metformin would attenuate hypoxia‐mediated decrements in exercise performance. On three separate randomly ordered occasions, 13 healthy men performed glycogen‐depleting exercise and ingested a low‐carbohydrate dinner (1200 kcals, <10% carbohydrate). The next morning, in either normoxia or hypoxia (FiO2=0.15), they ingested a high‐carbohydrate breakfast (1225 kcals, 70% carbohydrate). Placebo (719 mg maltodextrin) or metformin (500 mg BID) was consumed 3 days prior to each hypoxia visit. Subjects completed a 12.5 km cycle ergometer time trial 3.5 hours following breakfast. Hypoxia decreased resting and exercise oxyhemoglobin saturation (P<.001). Neither hypoxia nor metformin affected the glucose response to breakfast (P=.977), however, compared with placebo, metformin lowered insulin concentration in hypoxia 45 minutes after breakfast (64.1±6.6 μU/mL vs 48.5±7.8 μU/mL; mean±SE; P<.001). Post‐breakfast, pre‐exercise vastus lateralis glycogen content increased in normoxia (+33%: P=.025) and in hypoxia with metformin (+81%; P=.006), but not in hypoxia with placebo (+27%; P=.167). Hypoxia decreased time trial performance compared with normoxia (P<.01). This decrement was similar with placebo (+2.6±0.8 minutes) and metformin (+1.6±0.3 minutes). These results indicate that metformin promotes glycogen synthesis but not endurance exercise performance in healthy men exposed to simulated high altitude. 相似文献
62.
Differences in Selected HIV Care Continuum Outcomes Among People Residing in Rural,Urban, and Metropolitan Areas—28 US Jurisdictions 下载免费PDF全文
John A. Nelson PhD Anna Kinder MS Anna Satcher Johnson MPH H. Irene Hall PhD Xiaohong Hu MS Donna Sweet MD Alyssa Guido MPH Harold Katner MD Jennifer Janelle MD Maribel Gonzalez MSN Natalia Martínez Paz MA MPA Charlotte Ledonne BSN MA Jason Henry Theresa Bramel MHS Jeanne Harris BSN MBA 《The Journal of rural health》2018,34(1):63-70
Purpose
The HIV care continuum is used to monitor success in HIV diagnosis and treatment among persons living with HIV in the United States. Significant differences exist along the HIV care continuum between subpopulations of people living with HIV; however, differences that may exist between residents of rural and nonrural areas have not been reported.Methods
We analyzed the Centers for Disease Control and Prevention's National HIV Surveillance System data on adults and adolescents (≥13 years) with HIV diagnosed in 28 jurisdictions with complete reporting of HIV‐related lab results. Lab data were used to assess linkage to care (≥1 CD4 or viral load test ≤3 months of diagnosis), retention in care (≥2 CD4 and/or viral load tests ≥3 months apart), and viral suppression (viral load <200 copies/mL) among persons living with HIV. Residence at diagnosis was grouped into rural (<50,000 population), urban (50,000‐499,999 population), and metropolitan (≥500,000 population) categories for statistical comparison. Prevalence ratios and 95% CI were calculated to assess significant differences in linkage, retention, and viral suppression.Findings
Although greater linkage to care was found for rural residents (84.3%) compared to urban residents (83.3%) and metropolitan residents (81.9%), significantly lower levels of retention in care and viral suppression were found for residents of rural (46.2% and 50.0%, respectively) and urban (50.2% and 47.2%) areas compared to residents of metropolitan areas (54.5% and 50.8%).Conclusions
Interventions are needed to increase retention in care and viral suppression among people with HIV in nonmetropolitan areas of the United States. 相似文献63.
64.
M. Alexandra Friedman Charlotte M. Niznik Janelle R. Bolden Lynn M. Yee 《Journal of community health》2016,41(2):354-358
While peer support has been investigated in multiple clinical contexts, its application to the postpartum setting is unknown. The aim was to assess acceptability of a postpartum peer support program for women with diabetes. Observational survey-based needs assessment of forty low-income women with diabetes, receiving care at a major medical institution. Mean age and gravidity were 30.7 years and 3.15 ± 1.67 respectively. 45 % expressed interest in a “buddy.” There was no significant difference between groups desiring and not desiring this program. A majority of respondents desired telephone, text messaging, and in-person contacts (79.2, 72.1, 83.8 %), with 72.5 % of patients desiring diabetes-related activities during clinic waiting time. Many women desire a postpartum diabetes reciprocal peer program for support outside of clinician visits. Patients are receptive to educational services during their wait and outside of clinic time, a potentially valuable opportunity to share important health information. 相似文献
65.
Objective. To determine whether and how pharmacy students used knowledge learned in the classroom during their introductory pharmacy practice experiences (IPPEs) in community and hospital settings.Design. To reinforce course concepts and make connections between coursework and practice, students documented examples of how knowledge from first-year courses was used in IPPEs.Assessment. Data submitted were categorized by classroom-based pharmacy course, including the frequency with which each course was cited. For community practice experiences, most student examples of knowledge application related to the self-care therapeutics course, pharmacy practice laboratory course, and dose form/compounding laboratory courses. Hospital IPPE examples were most frequently based on the pharmaceutical calculations course, physiology/pathophysiology course, medicinal chemistry course, and pharmacy practice laboratory course.Conclusion. All prior classroom-based pharmacy courses were cited by students as being useful during IPPEs, although some were more frequently cited than others. This activity provided useful programmatic assessment data. 相似文献
66.
LaMontagne AD Youngstrom RA Lewiton M Stoddard AM Perry MJ Klar JM Christiani DC Sorensen G 《Applied occupational and environmental hygiene》2003,18(7):523-534
This article describes a new method for (1) systematically prioritizing needs for intervention on hazardous substance exposures in manufacturing work sites, and (2) evaluating intervention effectiveness. We developed a checklist containing six unique sets of yes/no variables organized in a 2 x 3 matrix of exposure potential versus protection (two columns) at the levels of materials, processes, and human interface (three rows). The three levels correspond to a simplified hierarchy of controls. Each of the six sets of indicator variables was reduced to a high/moderate/low rating. Ratings from the matrix were then combined to generate a single overall exposure prevention rating for each area. Reflecting the hierarchy of controls, material factors were weighted highest, followed by process, and then human interface. The checklist was filled out by an industrial hygienist while conducting a walk-through inspection (N = 131 manufacturing processes/areas in 17 large work sites). One area or process per manufacturing department was assessed and rated. Based on the resulting Exposure Prevention ratings, we concluded that exposures were well controlled in the majority of areas assessed (64% with rating of 1 or 2 on a 6-point scale), that there is some room for improvement in 26 percent of areas (rating of 3 or 4), and that roughly 10 percent of the areas assessed are urgently in need of intervention (rated as 5 or 6). A second hygienist independently assessed a subset of areas to evaluate inter-rater reliability. The reliability of the overall exposure prevention ratings was excellent (weighted kappa = 0.84). The rating scheme has good discriminatory power and reliability and shows promise as a broadly applicable and inexpensive tool for intervention needs assessment and effectiveness evaluation. Validation studies are needed as a next step. This assessment method complements quantitative exposure assessment with an upstream prevention focus. 相似文献
67.
Johnston L Reid A Wilson J Levesque J Driver B 《The Australian journal of rural health》2007,15(4):252-256
OBJECTIVE: Recognition of depression in the elderly is exacerbated in rural and remote regions by a lack of mental health specialists. In nursing homes, screening tools have been advocated to circumvent the variable reliability of both nursing staff and residents in recognising depression. Debate concerning the utility of screening tools abounds. Previous research has neglected concordance between screening tools, nursing staff and residents in recognising depression. The present study aimed to determine if there was a significant difference in the proportion of depressed residents identified by recognition sources, and assessed the level of chance corrected agreement between sources. PARTICIPANTS: One hundred and two residents of aged care facilities in Wagga Wagga, Australia, mean age of 85.19 +/- 7.09 years. SETTING: Residents were interviewed within their residential aged care facility. DESIGN: Cross-sectional, between-subjects design. MAIN OUTCOME MEASURES: Residents, nursing staff, Geriatric Depression Scale (GDS-12R) and Hamilton Depression Rating Scale. RESULTS: Hamilton Depression Rating Scale and nursing staff professional opinion were not significantly different; however, both measures were significantly different to the resident measures (GDS-12R and resident opinion). Kappa statistic analysis of outcome measures revealed, at best, no more than a moderate level of chance corrected agreement between said sources. CONCLUSION: It is tentatively argued that the different sources might correspond to qualitatively different 'depression' constructs, and that health professionals who are concerned with depression in the elderly be aware of the disparity between, and subsequently consider, a variety of recognition sources. 相似文献
68.
69.
OBSTETRIC OUTCOMES IN AN ABORIGINAL COMMUNITY: A COMPARISON WITH THE SURROUNDING RURAL AREA 总被引:1,自引:0,他引:1
Antenatal, intranatal and postnatal features of all Aboriginal women who lived at Cherbourg Aboriginal Community and delivered during 1990, 1991 and 1992 were compared with all non-Aboriginal women in the same rural area who delivered at Kingaroy Base Hospital during 1991. Almost all the Aboriginal women also delivered at Kingaroy. The data for 146 Aboriginal and 139 non-Aboriginal women were taken from the hospital records. The Aboriginal women were generally younger at delivery (Aboriginal 35% younger than 20 years vs non-Aboriginal 12%), made their first antenatal visit later (Aboriginal 49% after 20 weeks vs non-Aboriginal 10%) and made fewer antenatal visits (Aboriginal 43% < 4 visits vs non-Aboriginal 2% < 4 visits). They were more likely to be anaemic (Aboriginal 65% < 110 g/L vs non-Aboriginal 13% < 110 g/L), have a sexually transmitted disease (STD; Aboriginal 13% vs non-Aboriginal 2%) and drink alcohol (Aboriginal 54% vs non-Aboriginal 32%). After making an allowance for repeat Caesarean sections, there was no significant difference in the proportion of abnormal deliveries, but birthweights of Aboriginal infants were lower. Postnatally, the only significant difference between the two groups was a lower incidence of jaundice in Aboriginal infants. Multifactorial analysis showed that birthweights were significantly decreased by primagravidy, alcohol intake and STD. It is likely that the effects of STD and alcohol on birthweight were due to associated lifestyle factors. When these factors were allowed for, ethnic background had no significant effect on birthweight. 相似文献
70.