全文获取类型
收费全文 | 208986篇 |
免费 | 18143篇 |
国内免费 | 4485篇 |
专业分类
耳鼻咽喉 | 3256篇 |
儿科学 | 4073篇 |
妇产科学 | 3565篇 |
基础医学 | 16585篇 |
口腔科学 | 7181篇 |
临床医学 | 19231篇 |
内科学 | 19981篇 |
皮肤病学 | 2384篇 |
神经病学 | 10291篇 |
特种医学 | 5669篇 |
外国民族医学 | 11篇 |
外科学 | 20253篇 |
综合类 | 33237篇 |
现状与发展 | 9篇 |
一般理论 | 24篇 |
预防医学 | 28423篇 |
眼科学 | 1985篇 |
药学 | 20196篇 |
337篇 | |
中国医学 | 25887篇 |
肿瘤学 | 9036篇 |
出版年
2024年 | 948篇 |
2023年 | 4198篇 |
2022年 | 7890篇 |
2021年 | 10360篇 |
2020年 | 10132篇 |
2019年 | 11392篇 |
2018年 | 10076篇 |
2017年 | 8632篇 |
2016年 | 7690篇 |
2015年 | 7154篇 |
2014年 | 14078篇 |
2013年 | 14315篇 |
2012年 | 12597篇 |
2011年 | 13470篇 |
2010年 | 10852篇 |
2009年 | 9366篇 |
2008年 | 8670篇 |
2007年 | 8748篇 |
2006年 | 7440篇 |
2005年 | 6285篇 |
2004年 | 5213篇 |
2003年 | 4646篇 |
2002年 | 3582篇 |
2001年 | 2968篇 |
2000年 | 2639篇 |
1999年 | 2158篇 |
1998年 | 1718篇 |
1997年 | 1548篇 |
1996年 | 1247篇 |
1995年 | 1193篇 |
1994年 | 1088篇 |
1993年 | 968篇 |
1992年 | 881篇 |
1991年 | 807篇 |
1990年 | 704篇 |
1989年 | 683篇 |
1988年 | 632篇 |
1987年 | 570篇 |
1986年 | 523篇 |
1985年 | 1784篇 |
1984年 | 2065篇 |
1983年 | 1289篇 |
1982年 | 1711篇 |
1981年 | 1187篇 |
1980年 | 1015篇 |
1979年 | 905篇 |
1978年 | 748篇 |
1977年 | 560篇 |
1976年 | 698篇 |
1975年 | 479篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Xiao-Bing Liu Jia-Xi Lu Li-Juan Wang Yi-Chun Hu Rui Wang De-Qian Mao Jian Huang Li-Yun Zhao Xiao-Guang Yang Li-Chen Yang 《Nutrients》2021,13(4)
Objective: The purpose of this study was to evaluate serum zinc status of pregnant women in the China Adult Chronic Disease and Nutrition Surveillance (CACDNS) in 2015–2016. Methods: A total of 7147 apparently healthy pregnant women were randomly selected in 302 national monitoring sites. Information on age, race, residence region, education, pregnancy, and family income per annum was collected, and the concentration of serum zinc was determined. The evaluation of serum zinc status was further performed according to the recommendations by the International Zinc Nutrition Consultative Group (IZiNCG). Results: The median concentration of serum zinc was 858.9 μg/L with an interquartile range (IQR) of 712.9 μg/L and 1048.9 μg/L, while the overall prevalence of zinc deficiency was 3.5% with a 95% confidence interval (CI) of 3.0% and 3.9%. Serum zinc status of pregnant women changed greatly in the different categories, particular in pregnancy and family income per annum (p < 0.05), but no significant difference was observed in the prevalence of zinc deficiency (p > 0.05). Conclusions: The lower prevalence of zinc deficiency generally indicated a better zinc status for pregnant women in the CACDNS in 2015–2016. However, a well-designed evaluation system of zinc status for pregnant women should be continually optimized and improved by inducing more parameters such as biochemical, dietary, or functional indicators. 相似文献
992.
While several studies have explored nutrient intake and dietary habits associated with depression, few studies have reflected recent trends and demographic factors. Therefore, we examined how nutrient intake and eating habits are associated with depression, according to gender and age. We performed simple and multiple regressions using nationally representative samples of 10,106 subjects from the Korea National Health and Nutrition Examination Survey. The results indicated that cholesterol, dietary fiber, sodium, frequency of breakfast, lunch, dinner, and eating out were significantly associated with depression (p-value < 0.05). Moreover, depression was associated with nutrient intake and dietary habits by gender and age group: sugar, breakfast, lunch, and eating out frequency in the young women’s group; sodium and lunch frequency among middle-age men; dietary fibers, breakfast, and eating out frequency among middle-age women; energy, moisture, carbohydrate, lunch, and dinner frequency in late middle-age men; breakfast and lunch frequency among late middle-age women; vitamin A, carotene, lunch, and eating out frequency among older age men; and fat, saturated fatty acids, omega-3 fatty acid, omega-6 fatty acid, and eating out frequency among the older age women’s group (p-value < 0.05). This study can be used to establish dietary strategies for depression prevention, considering gender and age. 相似文献
993.
Mireia Vilamala-Orra Cristina Vaqu-Crusellas Quintí Foguet-Boreu Marta Guimer Gallent Ruben del Río Sez 《Nutrients》2021,13(6)
Despite growing evidence of the benefits of adequate intake of fruit and vegetables (F&V) and the recommendation to consume five servings daily, the adoption of these habits is poor among people with severe mental disorder (SMD). The main aim of the present study is to determine changes in the intake of F&V and motivation to do so among people with SMDs after participating in a food education programme. A community-based randomized controlled trial was conducted in Spain, with the intervention group (IG) participating in a food education programme based on the stages of change model to promote consumption of F&V and the control group (CG) receiving three informative sessions on basic healthy eating. The main outcomes were related to the intake of F&V and stages of change. Data collection was performed at baseline, post intervention, and 12-month follow-up. Seventy-four participants enrolled in the study and sixty completed the 12-month follow-up. An increase in motivation towards the intake of F&V was observed in the IG but not in the CG (McNemar’s test p = 0.016, p = 0.625). No significant difference was observed for the intake of fruit, vegetables, or F&V. Basing food education strategies on the stages of change model shows positive results, increasing the awareness and disposition of people with SMD towards the intake of F&V. More research is needed to identify the most appropriate eating intervention to increase the intake of F&V. 相似文献
994.
Yoshitake Baba Shun Inagaki Sae Nakagawa Makoto Kobayashi Toshiyuki Kaneko Takanobu Takihara 《Nutrients》2021,13(5)
Matcha, a type of green tea, has a higher amino acid content than other types of tea. We previously examined the ability of matcha to improve cognitive function in older adults and determined that continuous matcha intake improves attention and executive function. This study aimed to compare the effects of matcha and caffeine and clarify the differences between these effects. The study was registered at the University Hospital Medical Information Network (UMIN000036578). The effect of single and continuous intake was compared, and the usefulness of continuous intake was evaluated under the stress condition. The Uchida–Kraepelin test (UKT) was used to induce mild acute stress, and the Cognitrax was used to evaluate cognitive function. A single dose of caffeine improved attentional function during or after stress loading. The reduced reaction time in the Cognitrax, observed following a single dose of matcha, was likely due to caffeine. The matcha group showed an increase in the amount of work after continuous intake, whereas the caffeine group only showed an increase in the amount of work for the UKT after a single dose. Ingesting matcha with caffeine improves both attention and work performance when suffering from psychological stress compared with caffeine alone. 相似文献
995.
Maternal and infant nutrition are problematic in areas of Ethiopia. Health extension workers (HEWs) work in Ethiopia’s primary health care system, increasing potential health service coverage, particularly for women and children, providing an opportunity for health improvement. Their roles include improving maternal and infant nutrition, disease prevention, and health education. Supporting HEWs’ practice with ‘non-clinical’ skills in behavior change and health communication can improve effectiveness. This intervention study adapted and delivered a UK-developed training intervention for Health Extension Workers (HEWs) working with the United Nations World Food Programme in Ethiopia. The intervention included communication and behavioral training adapted with local contextual information. Mixed methods evaluation focused on participants’ reaction to training, knowledge, behavior change, and skills use. Overall, 98 HEWs were trained. The intervention was positively received by HEWs. Pre-post evaluations of communication and behavior change skills found a positive impact on HEW skills, knowledge, and motivation to use skills (all p < 0.001) to change women’s nutritional behavior, also demonstrated in role-play scenarios. The study offered substantial learning about intervention delivery. Appropriate cultural adaptation and careful consideration of assessment of psychological constructs are crucial for future delivery. 相似文献
996.
997.
《Journal of the Academy of Nutrition and Dietetics》2021,121(4):678-687.e1
BackgroundNationally, approximately one-third of early childhood education centers participating in the Child and Adult Care Food Program (CACFP) are independently owned and operated (ie, not owned by a corporation, not affiliated with Head Start, and with no food program sponsor). Independent providers are less likely to meet CACFP standards and best practices and would benefit from additional support and technical assistance.ObjectiveTo explore independent early childhood education center key informants’ (KIs) (ie, directors or relevant staff) perspectives on implementing the revised CACFP standards.DesignFollowing qualitative exploratory design, semistructured, in-depth, telephone interviews were conducted with KIs individually.Participants/settingIn summer 2018, 30 randomly sampled KIs from independent CACFP-participating early childhood education centers serving children ages 2 to 5 years nationwide were interviewed. Participants were sampled from respondents to a previously completed nationwide survey of providers.Main outcomesKIs’ perspectives on the CACFP program and revised meal pattern standard implementation.Analysis performedAfter audio recordings were professionally transcribed and reviewed, constant comparative analysis was conducted using Atlas.ti v8 qualitative software (Atlas.ti. version 8 for Windows, 2018, Scientific Software Development GmbH).ResultsKIs indicated that program benefits (eg, health and nutrition benefits, reimbursement, guidelines, and training) outweighed challenges experienced. Challenges associated with revised CACFP standards implementation (eg, availability or acceptability of new, creditable foods) were impacted by enhanced CACFP standards status, reported revised standards, and availability or utilization of outside support. KIs desired more contact with their state representative. KIs found the training and technical assistance on the revised standards useful and suggestions to enhance future training and technical assistance (eg, increasing accessibility, training resources, and audience-specific training).ConclusionsOverall, KIs desired additional resources, training, and increased communication from CACFP state representatives specific to CACFP-approved and reimbursable products, menu ideas, recipes, and cooking demonstrations. The present study suggests that a more tailored training and technical assistance approach is necessary as reported benefits, challenges, and program needs varied based on state-enhanced CACFP standards, reported familiarity with the revised meal pattern, and reported outside support. 相似文献
998.
Anthony Xiang Wei Hou Sina Rashidian Richard N Rosenthal Kayley Abell-Hart Xia Zhao Fusheng Wang 《JMIR Public Health and Surveillance》2021,7(4)
BackgroundOpioid overdose-related deaths have increased dramatically in recent years. Combating the opioid epidemic requires better understanding of the epidemiology of opioid poisoning (OP) and opioid use disorder (OUD).ObjectiveWe aimed to discover geospatial patterns in nonmedical opioid use and its correlations with demographic features related to despair and economic hardship, most notably the US presidential voting patterns in 2016 at census tract level in New York State.MethodsThis cross-sectional analysis used data from New York Statewide Planning and Research Cooperative System claims data and the presidential voting results of 2016 in New York State from the Harvard Election Data Archive. We included 63,958 patients who had at least one OUD diagnosis between 2010 and 2016 and 36,004 patients with at least one OP diagnosis between 2012 and 2016. Geospatial mappings were created to compare areas of New York in OUD rates and presidential voting patterns. A multiple regression model examines the extent that certain factors explain OUD rate variation.ResultsSeveral areas shared similar patterns of OUD rates and Republican vote: census tracts in western New York, central New York, and Suffolk County. The correlation between OUD rates and the Republican vote was .38 (P<.001). The regression model with census tract level of demographic and socioeconomic factors explains 30% of the variance in OUD rates, with disability and Republican vote as the most significant predictors.ConclusionsAt the census tract level, OUD rates were positively correlated with Republican support in the 2016 presidential election, disability, unemployment, and unmarried status. Socioeconomic and demographic despair-related features explain a large portion of the association between the Republican vote and OUD. Together, these findings underscore the importance of socioeconomic interventions in combating the opioid epidemic. 相似文献
999.
Anselme Millogo Ahmed Loukil Coralie LOllivier Diakourga Arthur Djibougou Sylvain Godreuil Michel Drancourt 《Emerging infectious diseases》2021,27(6):1758
Mycobacterium leprae was detected by optical microscopy, fluorescent in situ hybridization, and molecular detection in feces collected for the diagnosis of Entamoeba coli enteritis in a leprosy patient in Burkina Faso. This observation raises questions about the role of fecal excretion of M. leprae in the natural history and diagnosis of leprosy. 相似文献
1000.