全文获取类型
收费全文 | 1784篇 |
免费 | 128篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 60篇 |
妇产科学 | 29篇 |
基础医学 | 260篇 |
口腔科学 | 5篇 |
临床医学 | 269篇 |
内科学 | 270篇 |
皮肤病学 | 19篇 |
神经病学 | 337篇 |
特种医学 | 26篇 |
外科学 | 97篇 |
综合类 | 5篇 |
一般理论 | 1篇 |
预防医学 | 291篇 |
眼科学 | 10篇 |
药学 | 115篇 |
肿瘤学 | 105篇 |
出版年
2023年 | 14篇 |
2022年 | 33篇 |
2021年 | 63篇 |
2020年 | 21篇 |
2019年 | 49篇 |
2018年 | 62篇 |
2017年 | 44篇 |
2016年 | 43篇 |
2015年 | 55篇 |
2014年 | 67篇 |
2013年 | 93篇 |
2012年 | 161篇 |
2011年 | 155篇 |
2010年 | 69篇 |
2009年 | 70篇 |
2008年 | 131篇 |
2007年 | 117篇 |
2006年 | 105篇 |
2005年 | 98篇 |
2004年 | 109篇 |
2003年 | 95篇 |
2002年 | 76篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 14篇 |
1998年 | 12篇 |
1997年 | 4篇 |
1996年 | 12篇 |
1995年 | 4篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 8篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1965年 | 5篇 |
排序方式: 共有1915条查询结果,搜索用时 859 毫秒
61.
62.
Andersen BL Shelby RA Golden-Kreutz DM 《Journal of consulting and clinical psychology》2007,75(6):927-938
Little is known about the therapeutic processes contributing to efficacy of psychological interventions for patients with cancer. Data from a randomized clinical trial yielding robust biobehavioral and health effects (B. L. Andersen et al., 2004, 2007) were used to examine associations between process variables, treatment utilization, and outcomes. Novel findings emerged. Patients were highly satisfied with the treatment, but their higher levels of felt support (group cohesion) covaried with lower distress and fewer symptoms. Also, specific treatment strategies were associated with specific outcomes, including lower distress, improved dietary habits, reduced symptomatology, and higher chemotherapy dose intensity. These data provide a comprehensive test of multiple therapeutic processes and mechanisms for biobehavioral change with an intervention including both intensive and maintenance phases. 相似文献
63.
Activation induced cell death (AICD) via Fas/FasL is the primary homeostatic molecular mechanism employed by the immune system to control activated T-cell responses and promote tolerance to self-antigens. We herein investigated the ability of a novel multimeric form of FasL chimeric with streptavidin (SA-FasL) having potent apoptotic activity to induce apoptosis in diabetogenic T cells and modulate insulin-dependent type 1 diabetes (IDDM) in an adoptive transfer model. Diabetogenic splenocytes from NOD/Lt females were co-cultured in vitro with SA-FasL, SA control protein, or alone without protein, and adoptively transferred into NOD/Lt-Rag1(null) recipients for diabetes development. All animals receiving control (Alone: n=16 or SA: n=17) cells developed diabetes on average by 6 weeks, whereas animals receiving SA-FasL-treated (n=25) cells exhibited significantly delayed progression (p<.001) and decreased incidence (70%). This effect was associated with an increase in CD4(+)CD25(+) T cells and correlated with FoxP3 expression in pancreatic lymph nodes. Extracorporeal treatment of peripheral blood lymphocytes using SA-FasL during disease onset represents a novel approach that may alter the ability of pathogenic T cells to mediate diabetes and have therapeutic utility in clinical management of IDDM. 相似文献
64.
The calculation of absorbed dose to the radiosensitive tissues of the skeleton is routinely performed using reference masses provided in publications from the International Commission on Radiological Protection (ICRP). These values typically include total skeleton tissue masses by reference subject age, but not by individual bone site at a given age. Site-specific variations in absorbed fractions are known to occur for internal alpha-particle and beta-particle emitters, and in certain medical dose reconstructions, site-specific estimates of marrow dose may be desirable. Furthermore, bone-site-specific tissue masses are required to properly estimate skeletal-averaged absorbed fractions and, more importantly, specific absorbed fractions for internalized radionuclides and radiopharmaceuticals. Reference masses by skeletal site are also needed in the development of ICRP compliant tomographic phantoms, as this organ system is initially segmented from medical images only as a homogeneous tissue region. ICRP reference skeletal masses are assigned based upon several independent data sources, many of which may not be entirely consistent with one another. In this study, a methodology is presented, using data from the various ICRP publications, to derive site-specific skeletal tissue masses for each member of the ICRP age series. Active marrow masses are calculated and differences are shown with respect to ICRP Publications 70 and 89 values. New data for a revised surrogate tissue region for the osteoprogenitor cells within bone marrow is presented with estimates of its total mass throughout the skeleton and for different subject ages. 相似文献
65.
Maternal Multivitamin Intake,Plasma Folate and Vitamin B12 Levels and Autism Spectrum Disorder Risk in Offspring
下载免费PDF全文
![点击此处可从《Paediatric and perinatal epidemiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ramkripa Raghavan Anne W. Riley Heather Volk Deanna Caruso Lynn Hironaka Laura Sices Xiumei Hong Guoying Wang Yuelong Ji Martha Brucato Anastacia Wahl Tom Stivers Colleen Pearson Barry Zuckerman Elizabeth A. Stuart Rebecca Landa M. Daniele Fallin Xiaobin Wang 《Paediatric and perinatal epidemiology》2018,32(1):100-111
Background
To examine the prospective association between multivitamin supplementation during pregnancy and biomarker measures of maternal plasma folate and vitamin B12 levels at birth and child's Autism Spectrum Disorder (ASD) risk.Methods
This report included 1257 mother–child pairs, who were recruited at birth and prospectively followed through childhood at the Boston Medical Center. ASD was defined from diagnostic codes in electronic medical records. Maternal multivitamin supplementation was assessed via questionnaire interview; maternal plasma folate and B12 were measured from samples taken 2–3 days after birth.Results
Moderate (3–5 times/week) self‐reported supplementation during pregnancy was associated with decreased risk of ASD, consistent with previous findings. Using this as the reference group, low (≤2 times/week) and high (>5 times/week) supplementation was associated with increased risk of ASD. Very high levels of maternal plasma folate at birth (≥60.3 nmol/L) had 2.5 times increased risk of ASD [95% confidence interval (CI) 1.3, 4.6] compared to folate levels in the middle 80th percentile, after adjusting for covariates including MTHFR genotype. Similarly, very high B12 (≥536.8 pmol/L) showed 2.5 times increased risk (95% CI 1.4, 4.5).Conclusion
There was a ‘U shaped’ relationship between maternal multivitamin supplementation frequency and ASD risk. Extremely high maternal plasma folate and B12 levels at birth were associated with ASD risk. This hypothesis‐generating study does not question the importance of consuming adequate folic acid and vitamin B12 during pregnancy; rather, raises new questions about the impact of extremely elevated levels of plasma folate and B12 exposure in‐utero on early brain development. 相似文献66.
67.
68.
Jones JL Kruszon-Moran D Won K Wilson M Schantz PM 《The American journal of tropical medicine and hygiene》2008,78(1):35-39
Toxoplasma gondii and Toxocara spp. infections can cause systemic and ocular disease. To estimate the prevalence of infection with these organisms, we tested serum samples from persons > or = 12 years of age obtained in the Third National Health and Nutrition Examination Survey (1988-1994). Among those tested for both T. gondii and Toxocara spp. (n = 16,646), the age-adjusted T. gondii antibody prevalence was 23.6% (95% confidence limit [CL] = 22.1-25.1%) and the Toxocara spp. antibody prevalence was 14.0% (95% CL = 12.7-15.4%). Multivariate analysis controlling demographic and risk factors showed that persons infected with Toxocara spp. were more likely to be infected with T. gondii (odds ratio [OR] = 1.93, 95% CL = 1.61-2.31), and similarly, persons infected with T. gondii were more likely to be infected with Toxocara spp. (OR = 1.91, 95% CL = 1.59-2.28). Infection with T. gondii and Toxocara spp. are common and can be prevented by many similar interventions. 相似文献
69.
70.
Caitlin E. Kennedy Heena Brahmbhatt Samuel Likindikoki Sarah W. Beckham Jessie K. Mbwambo Deanna Kerrigan 《AIDS care》2014,26(3):275-281
Cash transfer programs seek to alter structural determinants of HIV risk such as poverty and gender inequality. We sought to explore the feasibility and potential effectiveness of a cash transfer intervention for young women as part of combination HIV prevention in Iringa, Tanzania. Qualitative, in-depth interviews were conducted with 116 stakeholders and residents from the region, including key informants, service delivery users, and members of key populations. Most respondents felt a cash transfer program would assist young women in Iringa to have more control over sexual decision-making and reduce poverty-driven transactional sex. Respondents were divided on who should receive funds: young women themselves, their parents/guardians, or community leaders. Cash amounts and suggested target groups varied, and several respondents suggested providing microcredit or small business capital instead of cash. Potential concerns included jealousy, dependency, and corruption. However, most respondents felt that some intervention was needed to address underlying poverty driving some sexual risk behavior. A cash transfer program could fill this role, ultimately reducing HIV, sexually transmitted infections, and unintended pregnancies. As increased attention is given to economic and structural interventions for HIV prevention, local input and knowledge should be considered in a program design. 相似文献