全文获取类型
收费全文 | 5857篇 |
免费 | 445篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 219篇 |
妇产科学 | 149篇 |
基础医学 | 733篇 |
口腔科学 | 45篇 |
临床医学 | 693篇 |
内科学 | 1057篇 |
皮肤病学 | 157篇 |
神经病学 | 666篇 |
特种医学 | 111篇 |
外科学 | 698篇 |
综合类 | 43篇 |
一般理论 | 2篇 |
预防医学 | 821篇 |
眼科学 | 77篇 |
药学 | 384篇 |
中国医学 | 1篇 |
肿瘤学 | 399篇 |
出版年
2024年 | 5篇 |
2023年 | 78篇 |
2022年 | 128篇 |
2021年 | 252篇 |
2020年 | 173篇 |
2019年 | 221篇 |
2018年 | 281篇 |
2017年 | 202篇 |
2016年 | 182篇 |
2015年 | 235篇 |
2014年 | 295篇 |
2013年 | 387篇 |
2012年 | 561篇 |
2011年 | 498篇 |
2010年 | 276篇 |
2009年 | 221篇 |
2008年 | 330篇 |
2007年 | 334篇 |
2006年 | 314篇 |
2005年 | 310篇 |
2004年 | 256篇 |
2003年 | 255篇 |
2002年 | 211篇 |
2001年 | 27篇 |
2000年 | 27篇 |
1999年 | 32篇 |
1998年 | 37篇 |
1997年 | 23篇 |
1996年 | 20篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1983年 | 5篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1970年 | 3篇 |
1969年 | 5篇 |
排序方式: 共有6311条查询结果,搜索用时 15 毫秒
91.
Anna J. Jovanovich Adit A. Ginde John Holmen Kristen Jablonski Rebecca L. Allyn Jessica Kendrick Michel Chonchol 《Nutrients》2014,6(6):2196-2205
Previous research has reported reduced serum 25-hydroxyvitamin D (25(OH)D) levels is associated with acute infectious illness. The relationship between vitamin D status, measured prior to acute infectious illness, with risk of community-acquired pneumonia (CAP) and sepsis has not been examined. Community-living individuals hospitalized with CAP or sepsis were age-, sex-, race-, and season-matched with controls. ICD-9 codes identified CAP and sepsis; chest radiograph confirmed CAP. Serum 25(OH)D levels were measured up to 15 months prior to hospitalization. Regression models adjusted for diabetes, renal disease, and peripheral vascular disease evaluated the association of 25(OH)D levels with CAP or sepsis risk. A total of 132 CAP patients and controls were 60 ± 17 years, 71% female, and 86% Caucasian. The 25(OH)D levels <37 nmol/L (adjusted odds ratio (OR) 2.57, 95% CI 1.08–6.08) were strongly associated with increased odds of CAP hospitalization. A total of 422 sepsis patients and controls were 65 ± 14 years, 59% female, and 91% Caucasian. The 25(OH)D levels <37 nmol/L (adjusted OR 1.75, 95% CI 1.11–2.77) were associated with increased odds of sepsis hospitalization. Vitamin D status was inversely associated with risk of CAP and sepsis hospitalization in a community-living adult population. Further clinical trials are needed to evaluate whether vitamin D supplementation can reduce risk of infections, including CAP and sepsis. 相似文献
92.
Kristen N. Missall Robin L. Hojnoski Ginna Moreano 《Early child development and care》2017,187(12):1896-1908
Variability in children’s early-learning home environments points to the need to better understand specific mechanisms of early mathematical development. We used a sample of 66 parent–preschool child dyads to describe parent-reported mathematical activities in the home and observed parent–child mathematical activities in a semi-structured play session. Data were examined to better understand the two methods of assessing the context of parent–child interactions related to mathematics. Parents reported engaging in a range of mathematical activities about 3–5 times per week, on average. Results from observed interactions indicated that parents engaged in math content/concept interactions in 32.5% of all observed intervals and children engaged in math content/concept interactions in 24.2% of all observed intervals. Although observed parent and child math content interactions were highly correlated, observed parent and child mathematical interactions were not correlated with parent-reported math activities. 相似文献
93.
Shuaizhang Li Jinghua Zhao Ruili Huang Jameson Travers Carleen Klumpp-Thomas Wenbo Yu Alexander D. MacKerell Jr. Srilatha Sakamuru Masato Ooka Fengtian Xue Nisha S. Sipes Jui-Hua Hsieh Kristen Ryan Anton Simeonov Michael F. Santillo Menghang Xia 《Environmental health perspectives》2021,129(4)
Background: Inhibition of acetylcholinesterase (AChE), a biomarker of organophosphorous and carbamate exposure in environmental and occupational human health, has been commonly used to identify potential safety liabilities. So far, many environmental chemicals, including drug candidates, food additives, and industrial chemicals, have not been thoroughly evaluated for their inhibitory effects on AChE activity. AChE inhibitors can have therapeutic applications (e.g., tacrine and donepezil) or neurotoxic consequences (e.g., insecticides and nerve agents).Objectives: The objective of the current study was to identify environmental chemicals that inhibit AChE activity using in vitro and in silico models.Methods: To identify AChE inhibitors rapidly and efficiently, we have screened the Toxicology in the 21st Century (Tox21) 10K compound library in a quantitative high-throughput screening (qHTS) platform by using the homogenous cell-based AChE inhibition assay and enzyme-based AChE inhibition assays (with or without microsomes). AChE inhibitors identified from the primary screening were further tested in monolayer or spheroid formed by SH-SY5Y and neural stem cell models. The inhibition and binding modes of these identified compounds were studied with time-dependent enzyme-based AChE inhibition assay and molecular docking, respectively.Results: A group of known AChE inhibitors, such as donepezil, ambenonium dichloride, and tacrine hydrochloride, as well as many previously unreported AChE inhibitors, such as chelerythrine chloride and cilostazol, were identified in this study. Many of these compounds, such as pyrazophos, phosalone, and triazophos, needed metabolic activation. This study identified both reversible (e.g., donepezil and tacrine) and irreversible inhibitors (e.g., chlorpyrifos and bromophos-ethyl). Molecular docking analyses were performed to explain the relative inhibitory potency of selected compounds.Conclusions: Our tiered qHTS approach allowed us to generate a robust and reliable data set to evaluate large sets of environmental compounds for their AChE inhibitory activity. https://doi.org/10.1289/EHP6993 相似文献
94.
95.
Endocrine abnormalities in HIV‐infected women are associated with peak viral load – the Children and Women: AntiRetrovirals and Markers of Aging (CARMA) Cohort 下载免费PDF全文
96.
Carol Dawson-Rose PhD Deena Shehadeh MSN RN-BC PHN Jennifer Hao BA Jasmine Barnard BA Ladan Khoddam-Khorasani MPH Adam Leonard MS MPH CPNP AAHIVS Kristen Clark MSN RN Eva Kersey BA Haley Mousseau MA Julie Frank LCSW MSW Aaron Miller PMHNP Adam Carrico PhD Amy Schustack EdD Yvette P. Cuca PhD 《Public health nursing (Boston, Mass.)》2020,37(3):363-370
97.
War experiences may have an extensive impact on the health status of the exposed populations. This population‐based study aimed to examine the relationship between war experiences and self‐reported general health in representative sample surveys from Bosnia‐Herzegovina (n = 3,313) and Kosovo (n = 1,000). Data were collected with face‐to‐face interviews fielded in the winter of 2003–2004. Logistic regression analysis was used to compute unadjusted and adjusted odds ratios (ORs). The adjusted effects of the extensiveness of war experiences on poor health were positive in both countries, but they were statistically significant only for Bosnia‐Herzegovina: OR = 1.04, 95% CI [1.00, 1.08] for Bosnia‐Herzegovina and OR = 1.03, 95% CI [0.98, 1.09] for Kosovo. The strongest observed effect was found for Kosovo only: The extensiveness of war experiences was relatively strongly related to longstanding health problems, OR = 1.09, 95% CI [1.03, 1.15]. We found that war experiences may contribute to increased poorer health in the exposed populations; however, the effects 4–9 years after the war ended were modest. Hence, war experiences seemed to be more strongly related to war‐related distress and posttraumatic stress disorder than to self‐reported general health. 相似文献
98.
The Patient Protection and Affordable Care Act (ACA) continues to be the subject of fierce political debate in the United States. Drawing on issue framing theory, together with research on wording effects in survey responding, we tested how common differences in the wording of ACA surveys relate to apparent public support for the law. We report on a content analysis of N = 376 U.S. national opinion surveys fielded during a more than six-year period, beginning 23 March 2010 (when President Obama signed the bill into law) and ending 8 November 2016 (Election Day), and use ordinary least squares (OLS) regression models to predict public support for the law as a function of variation in question wording. We coded questions gauging general sentiment toward the law for differences in issue labeling (e.g., Obamacare, Affordable Care Act), whether or not they referenced particular political entities (e.g., President Obama, Congress) or segments of the public (e.g., You, Your Family), various opinion metrics (e.g., Support, Favor), and different response options (e.g., Repeal, Expand) which we used to model aggregate levels of support. The results revealed several key differences in question wording—for example, generic references to the Healthcare Law were employed much more frequently than Obamacare or Affordable Care Act—a number of which reliably predicted aggregate levels of public support. The discussion considers possible explanations for these patterns and reiterates the value of attending to questionnaire design features when interpreting survey data about politically contentious health policy issues. 相似文献
99.
100.
Heather A. Pines Pamina M. Gorbach Robert E. Weiss Kristen Hess Ryan Murphy Terry Saunders Joelle Brown Peter A. Anton Ross D. Cranston 《AIDS and behavior》2013,17(3):1002-1015
We assessed the acceptability of three of over-the-counter products representative of potential rectal microbicide (RM) delivery systems. From 2009 to 2010, 117 HIV-uninfected males (79 %) and females (21 %) who engage in receptive anal intercourse participated in a 6-week randomized crossover acceptability trial. Participants received each of three products (enema, lubricant-filled applicator, suppository) every 2 weeks in a randomized sequence. CASI and T-ACASI scales assessed product acceptability via Likert responses. Factor analysis was used to identify underlying factors measured by each scale. Random effects models were fit to examine age and gender effects on product acceptability. Three underlying factors were identified: Satisfaction with Product Use, Sexual Pleasure, and Ease of Product Use. For acceptability, the applicator ranked highest; however, differences between product acceptability scores were greatest among females and younger participants. These findings indicate that RM delivery systems impact their acceptability and should be considered early in RM development to enhance potential use. 相似文献