全文获取类型
收费全文 | 3263篇 |
免费 | 190篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 73篇 |
妇产科学 | 80篇 |
基础医学 | 615篇 |
口腔科学 | 113篇 |
临床医学 | 294篇 |
内科学 | 711篇 |
皮肤病学 | 48篇 |
神经病学 | 331篇 |
特种医学 | 82篇 |
外科学 | 196篇 |
综合类 | 29篇 |
一般理论 | 1篇 |
预防医学 | 239篇 |
眼科学 | 58篇 |
药学 | 298篇 |
中国医学 | 20篇 |
肿瘤学 | 263篇 |
出版年
2024年 | 5篇 |
2023年 | 28篇 |
2022年 | 118篇 |
2021年 | 189篇 |
2020年 | 96篇 |
2019年 | 116篇 |
2018年 | 115篇 |
2017年 | 79篇 |
2016年 | 119篇 |
2015年 | 110篇 |
2014年 | 169篇 |
2013年 | 194篇 |
2012年 | 289篇 |
2011年 | 323篇 |
2010年 | 174篇 |
2009年 | 108篇 |
2008年 | 226篇 |
2007年 | 195篇 |
2006年 | 199篇 |
2005年 | 169篇 |
2004年 | 141篇 |
2003年 | 117篇 |
2002年 | 97篇 |
2001年 | 12篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有3472条查询结果,搜索用时 15 毫秒
111.
Marko Lucijani Ana Jordan Ivana Jurin Nevenka Piska
ivkovi Ena Sori Irzal Hadibegovi Armin Ati Josip Stoji Diana Rudan Ozren Jaki Nikolina Bui Lovorka erek Ivica Luki Bruno Bari 《Croatian medical journal》2022,63(1):44
AimTo investigate clinical and prognostic associations of red cell distribution width (RDW) in hospitalized coronavirus disease 2019 (COVID-19) patients.MethodsWe retrospectively analyzed the records of 3941 consecutive COVID-19 patients admitted to a tertiary-level institution from March 2020 to March 2021 who had available RDW on admission.ResultsThe median age was 74 years. The median Charlson comorbidity index (CCI) was 4. The majority of patients (84.1%) on admission presented with severe or critical COVID-19. Patients with higher RDW were significantly more likely to be older and female, to present earlier during infection, and to have higher comorbidity burden, worse functional status, and critical presentation of COVID-19 on admission. RDW was not significantly associated with C-reactive protein, occurrence of pneumonia, or need for oxygen supplementation on admission. During hospital stay, patients with higher RDW were significantly more likely to require high-flow oxygen therapy, mechanical ventilation, intensive care unit, and to experience prolonged immobilization, venous thromboembolism, bleeding, and bacterial sepsis. Thirty-day and post-hospital discharge mortality gradually increased with each rising RDW percent-point. In a series of multivariate Cox-regression models, RDW demonstrated robust prognostic properties at >14% cut-off level. This cut-off was associated with inferior 30-day and post-discharge survival independently of COVID-19 severity, age, and CCI; and with 30-day survival independently of COVID severity and established prognostic scores (CURB-65, 4C-mortality, COVID-gram and VACO-index).ConclusionRDW has a complex relationship with COVID-19-associated inflammatory state and is affected by prior comorbidities. RDW can improve the prognostication in hospitalized COVID-19 patients.Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is a systemic infectious disease usually presenting with fever and respiratory symptoms (1). Although the most frequent serious manifestation of COVID-19 is pneumonia, the disease has been associated with cardiovascular, neurological, and gastrointestinal symptoms (2). Systemic inflammatory response mediated by high interleukin-6 concentrations induced by SARS-CoV-2 infection is associated with more severe clinical presentation, respiratory deterioration, and death (3,4). The presence of prior chronic comorbidities substantially affects the survival of COVID-19 patients (1).Anisocytosis, ie, unequal red blood cells (RBC) size, is a sensitive marker of distress in erythropoiesis or RBC destruction. It can be induced by various metabolic and inflammatory stimuli, nutrient deficiencies, infections, spleen disorders, and specific drugs interfering with RBC production (5). Anisocytosis can be quantified as a coefficient of variation of mean cell volume termed red blood cell distribution width (RDW), which is obtained by automatic cell counters. Higher RDW levels have recently gained attention as they are uniformly associated with unfavorable presentation and inferior outcomes in many chronic metabolic and malignant diseases (6-12). More severe clinical presentation and higher mortality rates were also found in COVID-19 patients with higher RDW levels (13-16). However, an association of RDW with other clinical outcomes in hospitalized COVID-19 patients, as well as the relationship with increased mortality in the context of other established prognostic scores, are not well defined. Thus, we aimed to investigate clinical and prognostic significance of RDW in a large cohort of hospitalized COVID-19 patients from our institution. We hypothesized that RDW was associated with more severe COVID-19 on admission and higher death rate. 相似文献
112.
Jelena Barbaric Giorgi Kuchukhidze Nicole Seguy Elena Vovc Maria Josefina Theresa Babovic Teodora Elvira Wi Daniel Low-Beer Ivana Bozicevic 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2022,27(8)
BackgroundEpidemics of sexually transmitted infections (STI) are a major public health challenge in the World Health Organization (WHO) European Region.AimWe aimed to provide an overview of case reporting and other surveillance data for syphilis, gonorrhoea and chlamydia for the non-European Union (EU)/European Economic Area (EEA) countries of the Centre and East part of the WHO European Region as per classification used by the WHO Regional Office for Europe (WHO/Europe) and the European Centre for Disease Prevention and Control.MethodsData were provided by the surveillance agencies of the Member States for the period 2015 to 2019 through the WHO/Europe Communicable Diseases Annual Reporting Form. We analysed reported cases, explored data reported to the WHO Gonococcal Antimicrobial Surveillance Programme (GASP) and performed a review of publications on antimicrobial resistance (AMR) in gonorrhoea in the period 2015 to 2020 using systematic methodology.ResultsFrom 2015 to 2019, in most of the countries with three or more data points, there was a pattern of decrease in reported syphilis, gonorrhoea and chlamydia cases, which is in contrast to the EU/EEA. The number of reported cases per 100,000 population was 0.4–26.5 for syphilis, 0–18.5 for gonorrhoea and 0–43.3 for chlamydia. Four countries reported recent data on AMR in gonorrhoea to GASP, and we identified further publications from Georgia, Russia and Ukraine.ConclusionWe found wide heterogeneity in reported rates of STI. There is a strong need to improve availability and quality of STI surveillance data in the non-EU/EEA countries. 相似文献
113.
High crystallinity leads to low hydrophilicity of fabric made of (poly(ethylene terephthalate)) fibers (PET) causing problems in finishing, washing, and dyeing processes. To improve these properties, the surface of PET fibers is usually modified by hydrolysis. Alkaline hydrolysis is a conventional process usually performed at a temperature higher than 100 °C for more than 1 h. However, the use of strong alkali and high processing temperatures (>100 °C) can lead to fabric damage and a negative impact on the environment. Therefore, in this paper, the possibility of hydrolysis of the PET fibers in the fabric in a sustainable, energy-efficient process was researched. The influence of low temperature (60–100 °C) and an accelerator (a cationic surfactant HDTMAC) to PET alkaline hydrolysis was studied through weight loss, the loss in breaking force, and fiber morphology. The kinetics of PET dissolution in 1.5 mol cm−3 NaOH at low temperature with and without the addition of HDTMAC was determined and the activation energy was calculated according to the theoretical model. It has been confirmed that PET hydrolysis can be carried out in 1.5 mol cm−3 NaOH with the addition of HDTMAC as an accelerator at 80 °C for 10 min. This process is more economically and energetically acceptable than the conventional process, and is therefore more sustainable. 相似文献
114.
Laurens Manning Ivana Bastos Ferreira Paul Gittings Jonathan Hiew Erica Ryan Mendel Baba Edward Raby Keryln Carville Paul E. Norman Wendy Angela Davis Fiona Wood Emma Jane Hamilton Jens Carsten Ritter 《International wound journal》2022,19(3):470
There is an urgent need for interventions that improve healing time, prevent amputations and recurrent ulceration in patients with diabetes‐related foot wounds. In this randomised, open‐label trial, participants were randomised to receive an application of non‐cultured autologous skin cells (“spray‐on” skin; ReCell) or standard care interventions for large (>6 cm2), adequately vascularised wounds. The primary outcome was complete healing at 6 months, determined by assessors blinded to the intervention. Forty‐nine eligible foot wounds in 45 participants were randomised. An evaluable primary outcome was available for all wounds. The median (interquartile range) wound area at baseline was 11.4 (8.8‐17.6) cm2. A total of 32 (65.3%) index wounds were completely healed at 6 months, including 16 of 24 (66.7%) in the spray‐on skin group and 16 of 25 (64.0%) in the standard care group (unadjusted OR [95% CI]: 1.13 (0.35‐3.65), P = .845). Lower body mass index (P = .002) and non‐plantar wounds (P = .009) were the only patient‐ or wound‐related factors associated with complete healing at 6 months. Spray‐on skin resulted in high rates of complete healing at 6 months in patients with large diabetes‐related foot wounds, but was not significantly better than standard care (Australian New Zealand Clinical Trials Registry: ACTRN12618000511235). 相似文献
115.
Ivana T. Croghan PhD Sandhya Pruthi MD J. Taylor Hays MD Stephen Cha MS Ruth E. Johnson MD Marianne Kosel AA Richard Morris BA Richard D. Hurt MD 《The breast journal》2009,15(5):489-495
Abstract: The purpose of this study was to assess the predictive value of smoking history on breast cancer diagnosis in a referral clinic population. We conducted a case–control study using clinical data collected on 8,097 female patients (1,225 breast cancer cases and 6,872 controls) seen in the Mayo Clinic Breast Clinic between August 1, 1993 and November 31, 2003. Breast cancer patients and noncancer patients significantly differed with respect to age at time of the index visit (p < 0.001), number of pregnancies (p = 0.006), number of live births (p = 0.002), vital status at last known follow-up (p < 0.001), current menstruation (p < 0.001), age at menopause (p < 0.001), history of hysterectomy (p < 0.001), use of oral contraception (p = 0.05), duration of oral contraception use (p = 0.001), use of other exogenous hormones (p < 0.001), duration of exogenous hormone use (p = 0.05), breast pain at time of index visit (p = 0.002), smoking status (p < 0.001), and use of five or more alcoholic beverages per week (p = 0.002). After adjustment for these baseline characteristics, having a personal history of smoking was found to be predictive of breast cancer diagnosis (odds ratios [OR] = 1.25, p = 0.004). Other positive predictors for breast cancer diagnosis were: age (OR = 1.02, p < 0.001), history of hysterectomy (OR = 0.66, p < 0.001), prior use of oral contraception for more than 11 years (OR = 2.10, p < 0.001), and prior use of other exogenous hormones/estrogen (OR = 1.81, p < 0.001). In this referral practice having a personal history of smoking is predictive of breast cancer diagnosis. Further studies are needed to further explore this relationship. 相似文献
116.
117.
Krijnen PA Hahn NE Kholová I Baylan U Sipkens JA van Alphen FP Vonk AB Simsek S Meischl C Schalkwijk CG van Buul JD van Hinsbergh VW Niessen HW 《Basic research in cardiology》2012,107(1):233-13
Pro-coagulant and pro-inflammatory intramyocardial (micro)vasculature plays an important role in acute myocardial infarction (AMI). Currently, inhibition of serine protease dipeptidyl peptidase 4 (DPP4) receives a lot of interest as an anti-hyperglycemic therapy in type 2 diabetes patients. However, DPP4 also possesses anti-thrombotic properties and may behave as an immobilized anti-coagulant on endothelial cells. Here, we studied the expression and activity of endothelial DPP4 in human myocardial infarction in relation to a prothrombogenic endothelial phenotype. Using (immuno)histochemistry, DPP4 expression and activity were found on the endothelium of intramyocardial blood vessels in autopsied control hearts (n?=?9). Within the infarction area of AMI patients (n?=?73), this DPP4 expression and activity were significantly decreased, coinciding with an increase in Tissue Factor expression. In primary human umbilical vein endothelial cells (HUVECs), Western blot analysis and digital imaging fluorescence microscopy revealed that DPP4 expression was strongly decreased after metabolic inhibition, also coinciding with Tissue Factor upregulation. Interestingly, inhibition of DPP4 activity with diprotin A also enhanced the amount of Tissue Factor encountered and induced the adherence of platelets under flow conditions. Ischemia induces loss of coronary microvascular endothelial DPP4 expression and increased Tissue Factor expression in AMI as well as in vitro in HUVECs. Our data suggest that the loss of DPP4 activity affects the anti-thrombogenic nature of the endothelium. 相似文献
118.
Marcelo A. do Nascimento Juan P. C. Vargas Jos G. A. Rodrigues Raquel A. C. Leo Patricia H. B. de Moura Ivana C. R. Leal Jonathan Bassut Rodrigo O. M. A. de Souza Robert Wojcieszak Ivaldo Itabaiana Jr 《RSC advances》2022,12(5):3027
Studies involving the transformation of lignocellulosic biomass into high value-added chemical products have been intensively conducted in recent years. Its matrix is mainly composed of cellulose, hemicellulose and lignin, being, therefore, an abundant and renewable source for obtaining several platform molecules, with levoglucosan (LG) standing out. This anhydrous carbohydrate can be acylated to obtain carbohydrate fatty acid esters (CFAEs). Here, these compounds were obtained via enzymatic acylation of LG, commercially obtained (Start BioScience®), with different acyl donors in continuous flow. Through the experimental design using a model reaction, it was possible to optimize the reaction conditions, temperature and residence time, obtaining a maximum conversion at 61 °C and 77 min. In addition, there was a productivity gain of up to 100 times in all comparisons made with the batch system. Finally, CFAEs were applied in tests of interfacial tension and biological activity. For a mixture of 4- and 2-O-lauryl-1,6-anhydroglucopyranose (MONLAU), the minimum interfacial tension (IFTmin) obtained was 96 mN m−1 and the critical micelle concentration (CMC) was 50 mM. Similar values were obtained for a mixture of 4- and 2-O-palmitoyl-1,6-anhydroglucopyranose (MONPAL), not yet reported in the literature, of 88 mN m−1 in 50 mM. For a mixture of 4- and 2-O-estearyl-1,6-anhydroglucopyranose (MONEST) and 4- and 2-O-oleoyl-1,6-anhydroglucopyranose (MONOLE), CMC was higher than 60 mM and IFTmin of 141 mN m−1 and 102 mN m−1, respectively. Promising data were obtained for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of MONLAU against Staphylococcus aureus strains at 0.25 mM.Ipase-catalyzed transesterification of LG under continuous flow conditions. 相似文献
119.
Recently, much attention has been paid to the reuse of bauxite residues from alumina production, also known as red mud, in the cement industry. Red mud bears the potential to improve concrete properties due to its favourable chemical composition and particle size. In this work, the synergy between locally available red mud and common supplementary cementitious materials such as fly ash, slag, calcined clay and limestone in cement mixes is investigated. All materials used were sourced from the immediate vicinity of the cement plant. The study of synergy involved the evaluation of the individual chemical reactivity of each material using the R3 test by isothermal calorimetry as well as their joint contribution to the heat of hydration and the composition of the reaction products of the paste and the compressive strength of the mortar. The results show how, by understanding the synergy between the materials, a higher level of cement substitutions can be achieved without compromising the mechanical properties of the mortar. 相似文献
120.
Ivana Perkovi? Martina Kne?evi? Romi? Marina Peri? Silvana Juki? Krmek 《Acta stomatologica Croatica》2014,48(4):258-267