首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   113490篇
  免费   8381篇
  国内免费   2825篇
耳鼻咽喉   644篇
儿科学   3408篇
妇产科学   2631篇
基础医学   10103篇
口腔科学   2073篇
临床医学   12271篇
内科学   23537篇
皮肤病学   932篇
神经病学   3778篇
特种医学   2454篇
外国民族医学   14篇
外科学   8932篇
综合类   14659篇
现状与发展   10篇
一般理论   1篇
预防医学   15552篇
眼科学   674篇
药学   12588篇
  61篇
中国医学   3956篇
肿瘤学   6418篇
  2024年   223篇
  2023年   1986篇
  2022年   3662篇
  2021年   5960篇
  2020年   4796篇
  2019年   4575篇
  2018年   4491篇
  2017年   3824篇
  2016年   4101篇
  2015年   4217篇
  2014年   7906篇
  2013年   8412篇
  2012年   7053篇
  2011年   7930篇
  2010年   6146篇
  2009年   5946篇
  2008年   6054篇
  2007年   5856篇
  2006年   4677篇
  2005年   4055篇
  2004年   3301篇
  2003年   2582篇
  2002年   1997篇
  2001年   1795篇
  2000年   1484篇
  1999年   1277篇
  1998年   1022篇
  1997年   977篇
  1996年   866篇
  1995年   741篇
  1994年   705篇
  1993年   580篇
  1992年   551篇
  1991年   515篇
  1990年   394篇
  1989年   365篇
  1988年   332篇
  1987年   317篇
  1986年   245篇
  1985年   409篇
  1984年   332篇
  1983年   214篇
  1982年   256篇
  1981年   229篇
  1980年   223篇
  1979年   199篇
  1978年   182篇
  1977年   125篇
  1976年   134篇
  1975年   91篇
排序方式: 共有10000条查询结果,搜索用时 562 毫秒
971.
Elderly women exhibit a high risk of type 2 diabetes (T2D), but no definitive data exist about the possible role of postmenopausal increases in visceral adiposity, the loss of lean body mass, or decreases in the sum of the lean mass of arms and legs (appendicular skeletal muscle mass (ASMM)). This retrospective, longitudinal study investigated whether body composition (bioelectrical impedance analysis) predicted the development of impaired fasting glucose (IFG) or T2D in a cohort of 159 elderly women (age: 71 ± 5 years, follow-up: 94 months) from southern Italy (Clinical Nutrition and Geriatric Units of the “Mater Domini” University Hospital in Catanzaro, Calabria region, and the “P. Giaccone ”University Hospital in Palermo, Sicily region). Sarcopenia was defined in a subgroup of 128 women according to the EWGSOP criteria as the presence of low muscle strength (handgrip strength <16 kg) plus low muscle mass (reported as appendicular skeletal muscle mass <15 kg). Participants with a low ASMM had a higher IFG/T2D incidence than those with a normal ASMM (17% vs. 6%, p-adjusted = 0.044); this finding was independent of BMI, fat mass, waist circumference, and habitual fat intake (OR = 3.81, p = 0.034). A higher incidence of IFG/T2D was observed in the subgroup with sarcopenia than those without sarcopenia (33% vs. 7%, p-adjusted = 0.005) independent of BMI and fat mass (OR = 6.75, p = 0.007). In conclusion, this study demonstrates that elderly women with low ASMM had a higher probability of developing IFG/T2D. Further studies are needed to confirm these results in men and in other age groups.  相似文献   
972.
The biomedical potential of the edible red seaweed Agarophyton chilense (formerly Gracilaria chilensis) has not been explored. Red seaweeds are enriched in polyunsaturated fatty acids and eicosanoids, which are known natural ligands of the PPARγ nuclear receptor. PPARγ is the molecular target of thiazolidinediones (TZDs), drugs used as insulin sensitizers to treat type 2 diabetes mellitus. Medical use of TZDs is limited due to undesired side effects, a problem that has triggered the search for selective PPARγ modulators (SPPARMs) without the TZD side effects. We produced Agarophyton chilense oleoresin (Gracilex®), which induces PPARγ activation without inducing adipocyte differentiation, similar to SPPARMs. In a diet-induced obesity model of male mice, we showed that treatment with Gracilex® improves insulin sensitivity by normalizing altered glucose and insulin parameters. Gracilex® is enriched in palmitic acid, arachidonic acid, oleic acid, and lipophilic antioxidants such as tocopherols and β-carotene. Accordingly, Gracilex® possesses antioxidant activity in vitro and increased antioxidant capacity in vivo in Caenorhabditis elegans. These findings support the idea that Gracilex® represents a good source of natural PPARγ ligands and antioxidants with the potential to mitigate metabolic disorders. Thus, its nutraceutical value in humans warrants further investigation.  相似文献   
973.
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   
974.
BackgroundAn inflammatory diet is related to poorer cognition, but the underlying brain pathways are unknown.ObjectiveThe aim of this study was to examine associations between the Energy-Adjusted Dietary Inflammatory Index (E-DII) and brain volume, small vessel disease, and cognition in people with and without type 2 diabetes mellitus (T2DM).DesignThis is a secondary cross-sectional analysis of data from the Cognition and Diabetes in Older Tasmanians study.Participants/settingsThis study included 641 participants (n = 326 with T2DM) enrolled between 2005 and 2011 from Tasmania, Australia.Main outcome measuresThe E-DII was computed from the 80-item Dietary Questionnaire for Epidemiological Studies, version 2. Brain volumes (gray matter, white matter, and white matter hyperintensities), infarcts, and microbleeds were obtained from magnetic resonance imaging. Global cognition was derived from a comprehensive battery of neuropsychological tests.Statistical analysisLogistic and linear regressions were performed to examine associations between E-DII and brain measures and a global cognitive score, adjusting for demographics, energy, T2DM, mood, ambulatory activity, and cardiovascular risk factors. An E-DII × T2DM interaction term was tested in each model.ResultsThe mean (standard deviation) age of participants was 69.8 (7.4) years. There were no associations between the E-DII and any of the brain structural measures or global cognitive function in fully adjusted models. There was a modification effect for T2DM on the association between E-DII and gray matter volume (T2DM: β = 1.38, 95% CI –3.03 to 5.79; without T2DM: β = –4.34, 95% CI, –8.52 to –0.16), but not with any of the other outcome measures.ConclusionsIn this cross-sectional study, E-DII was not associated with brain structure or global cognition. In 1 of the 7 outcomes, a significant modification effect for T2DM was found for the associations between E-DII and gray matter. Future prospective studies are needed to clarify the associations between diet-related inflammation and brain health.  相似文献   
975.
BackgroundSince the first reports of COVID-19 infection, the foremost requirement has been to identify a treatment regimen that not only fights the causative agent but also controls the associated complications of the infection. Due to the time-consuming process of drug discovery, physicians have used readily available drugs and therapies for treatment of infections to minimize the death toll.ObjectiveThe aim of this study is to provide a snapshot analysis of the major drugs used in a cohort of 1562 Pakistani patients during the period from May to July 2020, when the first wave of COVID-19 peaked in Pakistan.MethodsA retrospective observational study was performed to provide an overview of the major drugs used in a cohort of 1562 patients with COVID-19 admitted to the four major tertiary-care hospitals in the Rawalpindi-Islamabad region of Pakistan during the peak of the first wave of COVID-19 in the country (May-July 2020).ResultsAntibiotics were the most common choice out of all the therapies employed, and they were used as first line of treatment for COVID-19. Azithromycin was the most prescribed drug for treatment. No monthly trend was observed in the choice of antibiotics, and these drugs appeared to be a random but favored choice throughout the months of the study. It was also noted that even antibiotics used for multidrug resistant infections were prescribed irrespective of the severity or progression of the infection. The results of the analysis are alarming, as this approach may lead to antibiotic resistance and complications in immunocompromised patients with COVID-19. A total of 1562 patients (1064 male, 68.1%, and 498 female, 31.9%) with a mean age of 47.35 years (SD 17.03) were included in the study. The highest frequency of patient hospitalizations occurred in June (846/1562, 54.2%).ConclusionsGuidelines for a targeted treatment regime are needed to control related complications and to limit the misuse of antibiotics in the management of COVID-19.  相似文献   
976.
BackgroundHyderabad, Pakistan, was the first city to witness an outbreak of extensively drug resistant (XDR) typhoid fever. The outbreak strain is resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, fluoroquinolones, and third-generation cephalosporin, thus greatly limiting treatment options. However, despite over 5000 documented cases, information on mortality and morbidity has been limited.ObjectiveTo address the existing knowledge gap, this study aimed to assess the morbidity and mortality associated with XDR and non-XDR Salmonella serovar Typhi infections in Pakistan.MethodsWe reviewed the medical records of culture-confirmed typhoid cases in 5 hospitals in Hyderabad from October 1, 2016, to September 30, 2018. We recorded data on age, gender, onset of fever, physical examination, serological and microbiological test results, treatment before and during hospitalization, duration of hospitalization, complications, and deaths.ResultsA total of 1452 culture-confirmed typhoid cases, including 947 (66%) XDR typhoid cases and 505 (34%) non-XDR typhoid cases, were identified. Overall, ≥1 complications were reported in 360 (38%) patients with XDR typhoid and 89 (18%) patients with non-XDR typhoid (P<.001). Ileal perforation was the most commonly reported complication in both patients with XDR typhoid (n=210, 23%) and patients with non-XDR typhoid (n=71, 14%) (P<.001). Overall, mortality was documented among 17 (1.8%) patients with XDR S Typhi infections and 3 (0.6%) patients with non-XDR S Typhi infections (P=.06).ConclusionsAs this first XDR typhoid outbreak continues to spread, the increased duration of illness before hospitalization and increased rate of complications have important implications for clinical care and medical costs and heighten the importance of prevention and control measures.  相似文献   
977.
There exists a complex interaction between obesity, type 2 diabetes mellitus (T2DM) and cancer, and an increase in the incidence of cancer is expected with the growing obesity-diabetes pandemic. The association of cancer with diabetes mellitus and obesity appears to be site-specific, the highest risk being for post-menopausal breast cancer, endometrial cancer, and colorectal cancer. Moreover, there is worsening of hyperglycaemia with the onset of cancer, evidencing a bi-directional link between cancer and diabetes mellitus and the need for monitoring for diabetes in cancer survivors. In this review, we look at the epidemiological evidence from observational studies and Mendelian randomization studies linking obesity, diabetes, and cancer, as well as the complex pathophysiological mechanisms involved, including insulin resistance with associated hyperinsulinaemia, the effect of chronic low-grade inflammation, and the effect of various adipokines that are associated with obesity and T2DM. Additionally, we describe the novel therapeutic strategies, based on their role on the discrete pathophysiological mechanisms involved in the tumourigenesis.  相似文献   
978.
Paenibacillus thiaminolyticus is a nonvirulent organism found in human and ruminant microbiota. However, P. thiaminolyticus can act as an opportunistic pathogen in humans. We describe a case of abdominal wall hematoma secondarily infected by P. thiaminolyticus. Our findings emphasize the risk for unusual Paenibacillus infections in otherwise healthy persons.  相似文献   
979.
《Value in health》2021,24(12):1828-1834
Antimicrobial resistance is a serious challenge to the success and sustainability of our healthcare systems. There has been increasing policy attention given to antimicrobial resistance in the last few years, and increased amounts of funding have been channeled into funding for research and development of antimicrobial agents. Nevertheless, manufacturers doubt whether there will be a market for new antimicrobial technologies sufficient to enable them to recoup their investment. Health technology assessment (HTA) has a critical role in creating confidence that if valuable technologies can be developed they will be reimbursed at a level that captures their true value. We identify 3 deficiencies of current HTA processes for appraising antimicrobial agents: a methods-centric approach rather than problem-centric approach for dealing with new challenges, a lack of tools for thinking about changing patterns of infection, and the absence of an approach to epidemiological risks. We argue that, to play their role more effectively, HTA agencies need to broaden their methodological tool kit, design and communicate their analysis to a wider set of users, and incorporate long-term policy goals, such as containing resistance, as part of their evaluation criteria alongside immediate health gains.  相似文献   
980.
Using a relational approach, this study investigates whether shopping close to home moderates the relationship between the proximate food environment and diet. To address this question, we develop the proximate food retail quality (PFRQ) score, an inverse-distance weighted measure of all food retailers within a resident's neighborhood that incorporates audit data of each food retailer. This study relies on data collected through 24-h dietary recalls and psychosocial surveys administered to 449 adults in two socioeconomically matched neighborhoods. Food retailer audits collected data on the availability, price, and quality of healthful foods. Seventy-one percent of study participants report conducting at least 50% of their food shopping within approximately one mile of their home. Household income and education are associated with likelihood to shop close to home, while access to a personal vehicle is not. Finally, results suggest that, for residents who shop primarily close to home, a one unit increase in proximate food retail environment score is associated with a 17.2-point increase in HEI-2010 score, a measure of overall diet quality that ranges from zero to 100. This study suggests that the food environment matters for those who use it and that a low-quality proximate food environment can amplify individual disadvantage.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号