全文获取类型
收费全文 | 18404篇 |
免费 | 1025篇 |
国内免费 | 80篇 |
专业分类
耳鼻咽喉 | 238篇 |
儿科学 | 550篇 |
妇产科学 | 403篇 |
基础医学 | 2688篇 |
口腔科学 | 934篇 |
临床医学 | 2109篇 |
内科学 | 3555篇 |
皮肤病学 | 386篇 |
神经病学 | 1637篇 |
特种医学 | 367篇 |
外科学 | 1593篇 |
综合类 | 162篇 |
一般理论 | 12篇 |
预防医学 | 2146篇 |
眼科学 | 306篇 |
药学 | 1191篇 |
中国医学 | 95篇 |
肿瘤学 | 1137篇 |
出版年
2024年 | 20篇 |
2023年 | 191篇 |
2022年 | 370篇 |
2021年 | 722篇 |
2020年 | 418篇 |
2019年 | 632篇 |
2018年 | 702篇 |
2017年 | 501篇 |
2016年 | 487篇 |
2015年 | 597篇 |
2014年 | 780篇 |
2013年 | 967篇 |
2012年 | 1549篇 |
2011年 | 1670篇 |
2010年 | 825篇 |
2009年 | 699篇 |
2008年 | 1220篇 |
2007年 | 1151篇 |
2006年 | 1085篇 |
2005年 | 986篇 |
2004年 | 846篇 |
2003年 | 815篇 |
2002年 | 775篇 |
2001年 | 137篇 |
2000年 | 126篇 |
1999年 | 111篇 |
1998年 | 151篇 |
1997年 | 94篇 |
1996年 | 85篇 |
1995年 | 65篇 |
1994年 | 71篇 |
1993年 | 61篇 |
1992年 | 48篇 |
1991年 | 52篇 |
1990年 | 48篇 |
1989年 | 20篇 |
1988年 | 23篇 |
1987年 | 33篇 |
1986年 | 33篇 |
1985年 | 26篇 |
1984年 | 31篇 |
1983年 | 34篇 |
1982年 | 34篇 |
1981年 | 26篇 |
1980年 | 27篇 |
1979年 | 22篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1975年 | 11篇 |
1930年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Vinicius Rossa Luanne Ester Monteiro Ferreira Sancler da Costa Vasconcelos Eric Thomas Tai Shimabukuro Vinicius Gomes da Costa Madriaga Anna Paula Carvalho Sibele Berenice Castell Pergher Fernando de Carvalho da Silva Vitor Francisco Ferreira Carlos Adam Conte Junior Thiago de Melo Lima 《RSC advances》2022,12(22):14084
Nanotechnology experienced a great technological advance after the discovery of the graphene family (graphene – Gr, graphene oxide – GO, and reduced graphene oxide-rGO). Based on the excellent properties of these materials, it is possible to develop novel polymeric nanocomposites for several applications in our daily routine. One of the most prominent applications is for food packaging, offering nanocomposites with improved thermal, mechanical, anti-microbial, and barrier properties against gas and water vapor. This paper reviewed food packaging from its inception to the present day, with the development of more resistant and intelligent packaging. Herein, the most common combinations of polymeric matrices (derived from non-renewable and renewable sources) with Gr, GO, and rGO and their typical preparation methods are presented. Besides, the interactions present in these nanocomposites will be discussed in detail, and their final properties will be thoroughly analyzed as a function of the preparation technique and graphene family-matrix combinations.Food packaging based on nanotechnology of polymeric nanocomposites of graphene and graphene oxide results in packaging with better thermal, mechanical, antimicrobial, electrical packaging, moisture barrier and gas properties. 相似文献
103.
Juan Carlos Lopez-Delgado Teodoro Grau-Carmona Javier Trujillano-Cabello Carlos García-Fuentes Esther Mor-Marco Maria Luisa Bordeje-Laguna Esther Portugal-Rodriguez Carol Lorencio-Cardenas Paula Vera-Artazcoz Laura Macaya-Redin Juan Francisco Martinez-Carmona Lidn Mateu-Campos Maria Gero-Escapa Rosa Gastaldo-Simeon Belen Vila-García Jos Luis Flordelis-Lasierra Juan Carlos Montejo-Gonzalez Lluís Servia-Goixart the ENPIC Study Group 《Nutrients》2022,14(9)
Background: The present research aimed to evaluate the effect on outcomes of immunonutrition (IMN) enteral formulas during the intensive care unit (ICU) stay. Methods: A multicenter prospective observational study was performed. Patient characteristics, disease severity, nutritional status, type of nutritional therapy and outcomes, and laboratory parameters were collected in a database. Statistical differences were analyzed according to the administration of IMN or other types of enteral formulas. Results: In total, 406 patients were included in the analysis, of whom 15.02% (61) received IMN. Univariate analysis showed that patients treated with IMN formulas received higher mean caloric and protein intake, and better 28-day survival (85.2% vs. 73.3%; p = 0.014. Unadjusted Hazard Ratio (HR): 0.15; 95% CI (Confidence Interval): 0.06–0.36; p < 0.001). Once adjusted for confounding factors, multivariate analysis showed a lower need for vasopressor support (OR: 0.49; 95% CI: 0.26–0.91; p = 0.023) and continuous renal replacement therapies (OR: 0.13; 95% CI: 0.01–0.65; p = 0.049) in those patients who received IMN formulas, independently of the severity of the disease. IMN use was also associated with higher protein intake during the administration of nutritional therapy (OR: 6.23; 95% CI: 2.59–15.54; p < 0.001), regardless of the type of patient. No differences were found in the laboratory parameters, except for a trend toward lower triglyceride levels (HR: 0.97; 95% CI: 0.95–0.99; p = 0.045). Conclusion: The use of IMN formulas may be associated with better outcomes (i.e., lower need for vasopressors and continuous renal replacement), together with a trend toward higher protein enteral delivery during the ICU stay. These findings may ultimately be related to their modulating effect on the inflammatory response in the critically ill. NCT Registry: 03634943. 相似文献
104.
105.
Georgia Robins Sadler Paula R. Beerman Kathy Lee Jenny Hung Helene Nguyen Janet Cho Wennie Huang 《Journal of cancer education》2012,27(4):612-617
Asian American women's historically low breast cancer mortality rate has remained constant as rates decreased for all other races. From 2000 to 2004, a randomized controlled trial explored the Asian grocery store-based breast cancer education program's impact on Chinese, Filipino, Korean, and Vietnamese women (n?=?1,540). Women aged 40 and older and non-adherent for annual screening mammograms were more likely to schedule a mammogram after receiving the breast cancer education program than women randomized to the prostate cancer program (X 2?=?3.85, p?=?0.05). With the right program ingredients, late adopters of breast cancer screening can be prompted to change. 相似文献
106.
Paula Brown 《Journal of cancer education》2012,27(4):251-333
107.
Andréa Dâmaso Bertoldi Ana Paula Helfer Aline L Camargo Noêmia U L Tavares Panos Kanavos 《Globalization and health》2012,8(1):1-10
Non-communicable diseases account for more than 50% of deaths in adults aged 15–59 years in most low income countries. Depression and diabetes carry an enormous public health burden, making the identification of risk factors for these disorders an important strategy. While socio-economic inequalities in chronic diseases and their risk factors have been studied extensively in high-income countries, very few studies have investigated social inequalities in chronic disease risk factors in low or middle-income countries. Documenting chronic disease risk factors is important for understanding disease burdens in poorer countries and for targeting specific populations for the most effective interventions. The aim of this review is to systematically map the evidence for the association of socio-economic status with diabetes and depression comorbidity in low and middle income countries. The objective is to identify whether there is any evidence on the direction of the relationship: do co-morbidities have an impact on socio-economic status or vice versa and whether the prevalence of diabetes combined with depression is associated with socio-economic status factors within the general population. To date no other study has reviewed the evidence for the extent and nature of this relationship. By systematically mapping the evidence in the broader sense we can identify the policy and interventions implications of existing research, highlight the gaps in knowledge and suggest future research. Only 14 studies were found to analyse the associations between depression and diabetes comorbidity and socio-economic status. Studies show some evidence that the occurrence of depression among people with diabetes is associated with lower socio-economic status. The small evidence base that considers diabetes and depression in low and middle income countries is out of step with the scale of the burden of disease. 相似文献
108.
Danielle Barbosa Morais Tarcizio Antônio Rêgo de Paula Karine Moura de Freitas Sérgio Luis Pinto da Matta 《亚太生殖杂志》2012,1(4):303-307
ObjectiveTo describe the seminiferous epithelium cycle (SEC) by tubular morphology method, and the acrosomal development of individualizing spermatids, and to explore the distinction of the stages between two generations of spermatids.MethodsTesticular fragments were fixed in Karnovsky, embedded in glycol methacrylate and examined under light microscopy and transmission electron microscopy. Sections in 3 μm thickness were stained with toluidine blue for the characterization of the stages of the SEC by the tubular morphology method, or submitted to the PAS reaction for the visualization of the acrosomal formation. Additional details on the acrosomal formation were observed under transmission electron microscopy.ResultsThrough the eight stages described by tubular morphology method, 10 steps of acrosomal formation were observed in the spermatid development, called acrosomal steps. As the spermatids were produced in stage V of the tubular morphology method, it was at this stage from which began the steps of acrosomal development.ConclusionsWe propose association of the acrosomal steps for the first time, with the different stages by tubular morphology method. This method presents an alternative to the existent Methods, allowing interspecific comparisons of the SEC, not only among different species of bats, but also among the other mammals. 相似文献
109.
Introduction
High altitude training has become a mainstay in endurance sports, with live high–train low as the current protocol of choice. Athletes either live or sleep in artificial or natural hypoxic conditions with the aim to increase serum erythropoietin concentrations, which are thought to improve maximum oxygen uptake and thus exercise performance. 相似文献110.
The author describes an outline for a plan of care nurses could use in caring for patients undergoing a mastectomy. Needs of patients are categorized from the time of discovery of the lump until after mastectomy. Personal perceptions are documented; methods are explored for nurses to expand their knowledge. 相似文献