全文获取类型
收费全文 | 13315篇 |
免费 | 875篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 197篇 |
儿科学 | 296篇 |
妇产科学 | 253篇 |
基础医学 | 1869篇 |
口腔科学 | 1208篇 |
临床医学 | 1080篇 |
内科学 | 2981篇 |
皮肤病学 | 389篇 |
神经病学 | 973篇 |
特种医学 | 390篇 |
外国民族医学 | 1篇 |
外科学 | 1484篇 |
综合类 | 69篇 |
一般理论 | 6篇 |
预防医学 | 1339篇 |
眼科学 | 212篇 |
药学 | 921篇 |
中国医学 | 84篇 |
肿瘤学 | 492篇 |
出版年
2023年 | 118篇 |
2022年 | 311篇 |
2021年 | 508篇 |
2020年 | 348篇 |
2019年 | 466篇 |
2018年 | 547篇 |
2017年 | 363篇 |
2016年 | 402篇 |
2015年 | 431篇 |
2014年 | 588篇 |
2013年 | 718篇 |
2012年 | 1060篇 |
2011年 | 1108篇 |
2010年 | 622篇 |
2009年 | 488篇 |
2008年 | 707篇 |
2007年 | 774篇 |
2006年 | 610篇 |
2005年 | 590篇 |
2004年 | 479篇 |
2003年 | 397篇 |
2002年 | 376篇 |
2001年 | 285篇 |
2000年 | 283篇 |
1999年 | 211篇 |
1998年 | 78篇 |
1997年 | 65篇 |
1996年 | 59篇 |
1995年 | 54篇 |
1994年 | 49篇 |
1993年 | 40篇 |
1992年 | 88篇 |
1991年 | 88篇 |
1990年 | 91篇 |
1989年 | 64篇 |
1988年 | 64篇 |
1987年 | 73篇 |
1986年 | 61篇 |
1985年 | 54篇 |
1984年 | 57篇 |
1983年 | 43篇 |
1982年 | 36篇 |
1980年 | 21篇 |
1979年 | 35篇 |
1978年 | 28篇 |
1973年 | 22篇 |
1970年 | 23篇 |
1967年 | 25篇 |
1966年 | 23篇 |
1965年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Isabella Stelle Lorraine K. McDonagh Ilias Hossain Anastasia Z. Kalea Dora I. A. Pereira 《Nutrients》2021,13(4)
Introduction: In most sub-Saharan African countries iron deficiency anaemia remains highly prevalent in children and this has not changed in the last 25 years. Supplementation with iron hydroxide adipate tartrate (IHAT) was being investigated in anaemic children in a phase two clinical trial (termed IHAT-GUT), conducted at the Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine (LSHTM) (abbreviated as MRCG hereof). This qualitative study aimed to explore the personal perceptions of the trial staff in relation to conducting a clinical trial in such settings in order to highlight the health system specific needs and strengths in the rural, resource-poor setting of the Upper River Region in the Gambia. Methods: Individual interviews (n = 17) were conducted with local trial staff of the IHAT-GUT trial. Data were analysed using inductive thematic analysis. Results: Potential barriers and facilitators to conducting this clinical trial were identified at the patient, staff, and trial management levels. Several challenges, such as the rural location and cultural context, were identified but noted as not being long-term inhibitors. Participants believed the facilitators and benefits outnumbered the barriers, and included the impact on education and healthcare, the ambitious and knowledgeable locally recruited staff, and the local partnership. Conclusions: While facilitators and barriers were identified to conducting this clinical trial in a rural, resource-poor setting, the overall impact was perceived as beneficial, and this study is a useful example of community involvement and partnership for further health improvement programs. To effectively implement a nutrition intervention, the local health systems and context must be carefully considered through qualitative research beforehand. 相似文献
62.
Tanvir S Sian Ushnah S. U. Din Colleen S. Deane Ken Smith Amanda Gates Jonathan N. Lund John P. Williams Ricardo Rueda Suzette L. Pereira Bethan E. Phillips Philip J. Atherton 《Nutrients》2021,13(5)
Ageing is associated with postprandial muscle vascular and metabolic dysfunction, suggesting vascular modifying interventions may be of benefit. Reflecting this, we investigated the impact of acute cocoa flavanol (450–500 mg) intake (versus placebo control) on vascular (via ultrasound) and glucose/insulin metabolic responses (via arterialised/venous blood samples and ELISA) to an oral nutritional supplement (ONS) in twelve healthy older adults (50% male, 72 ± 4 years), in a crossover design study. The cocoa condition displayed significant increases in m. vastus lateralis microvascular blood volume (MBV) in response to feeding at 180 and 240-min after ONS consumption (baseline: 1.00 vs. 180 min: 1.09 ± 0.03, p = 0.05; 240 min: 1.13 ± 0.04, p = 0.002), with MBV at these timepoints significantly higher than in the control condition (p < 0.05). In addition, there was a trend (p = 0.058) for MBV in m. tibialis anterior to increase in response to ONS in the cocoa condition only. Leg blood flow and vascular conductance increased, and vascular resistance decreased in response to ONS (p < 0.05), but these responses were not different between conditions (p > 0.05). Similarly, glucose uptake and insulin increased in response to ONS (p < 0.05) comparably between conditions (p > 0.05). Thus, acute cocoa flavanol supplementation can potentiate oral feeding-induced increases in MBV in older adults, but this improvement does not relay to muscle glucose uptake. 相似文献
63.
Joana Raquel Raposo dos Santos Carlos Matias Dias Alexandre Chiavegatto Filho 《Health Policy and Technology》2021,10(1):79-86
ObjectiveIndividuals without private health insurance have less access to healthcare, therefore are more prone to experience poor health when compared to those who have. Segmentation is an approach to find homogenous groups of people with the purpose of tailoring services and products. In public policy, segmentation might be used to identify characteristics and needs of specific groups and deliver targeted programs and spare costs. We aim to identify and describe segments within the uninsured population to aid targeted policy actions and improve health.MethodsWe used secondary data collected from a representative, nationwide health survey (n=18,204). For the purpose of our analysis, we included data from individuals who answered “no” to the question: “Do you have private health insurance?” (n=12,134). Variables pertaining information on socio-demographic, health status, access and care were used. A multiple correspondence analysis was performed to find principal components followed by a hierarchical cluster.ResultsWe found three clusters. The first (54.12% of our sample) composed by a group of young, middle aged and professionally active individuals without health problems. The second (36.70%), a cluster of aging individuals composed especially by elderly women, either retired or fulfilling domestic tasks, with a long-term health problem. The last (9.17%) composed by elder people, with long-term health problem and scoring low in mental health related questions.ConclusionOur study found three clusters (profiles of individuals) among the uninsured. Ultimately, our findings aim to support policy makers to deliver customized actions to improve health and provide cost-effective policies. 相似文献
64.
Das hepatozellul re Karzinom ( HCC) ist mitmehr als 1 Million Erkrankungsf llen pro Jahrweltweit einer der h ufigsten malignen Tumoren[1] .Zweifellos ist das HCC- Tiermodell in der Strategiegegen HCC von gro er Bedeutung.Bisher stehtvielf ltige Verfahren zur Etabierung des HCC- Tier-modells zur Verf gung.Im folgenden wurde einHCC- Rattesmodell,das durch den Einsatz von allo-genischer Implantationstechnik erzeugt wurde,unddie betreffende Charaktere vorgestellt.1 MATERIAL UND … 相似文献
65.
66.
Miguel Relvas Ana Beco Luciano Pereira Ana Oliveira Jos Silvano Rui Silva Nídia Marques Lurdes Santos Luís Coentro Manuel Pestana 《Seminars in dialysis》2021,34(1):83-88
In peritoneal dialysis (PD), a cloudy dialysate is an alarming finding. Bacterial peritonitis is the most common cause, however, atypical infections and non‐infectious causes must be considered. A 46‐year‐old man presented with asthenia, paraesthesia, foamy urine and hypertension. Laboratory testing revealed severe azotaemia, anaemia, hyperkalaemia and nephrotic‐range proteinuria. Haemodialysis was started through a central venous catheter. Later, due to patient preference, a Tenckhoff catheter was inserted. Conversion to PD occurred 3 weeks later, during hospitalization for a presumed central line infection. A month later, the patient was hospitalized for neutropenic fever. He was diagnosed an acute parvovirus infection and was discharged under isoniazid for latent tuberculosis. Four months later, the patient presented with fever and a cloudy effluent. Peritoneal fluid (PF) cytology was suggestive of infectious peritonitis, but the symptoms persisted despite antibiotic therapy. Bacterial and mycological cultures were negative. No neoplastic cells were detected. Mycobacterium tuberculosis eventually grew in PF cultures, despite previous negative molecular tests. Directed therapy was then initiated with excellent response. Thus, facing a cloudy effluent, one must consider multiple aetiologies. Diagnosis of peritoneal tuberculosis is hampered by the lack of highly sensitive and specific exams. Here, diagnosis was only possible due to positive mycobacterial cultures. 相似文献
67.
Flavio Roberto Takeda Marcus Fernando Kodama Pertille Ramos Marina Alessandra Pereira Renan Rosetti Muniz Francisco Tustumi Tiago Biachi de Castria Rubens Antonio Aissar Sallum Bruno Zilberstein Ulysses Ribeiro Junior Ivan Cecconello 《American journal of surgery》2021,221(3):631-636
IntroductionAdenocarcinoma of the esophagogastric junction (AEGJ) represents a poor prognostic tumor. We evaluated the recurrence pattern and risk factors associated with recurrence in patients undergoing surgical resection by AEJG.MethodsRecurrences were categorized as locoregional, peritoneal, or distant. These three recurrence groups and a non-recurrence group were compared, and overall survival (OS) and disease-free survival (DFS) for each one was obtained.ResultsWe analyzed 188 patients with curative surgical treatment. Recurrence was observed in 72 (38.3%) patients. Locoregional recurrence was observed in 17 (23.6%); 20 (27.8%) peritoneal recurrence and 35 (48.6%) distant metastasis. DFS was 9, 5, and 8 months, and OS was 21.8, 13.2, and 20.8, respectively. Tumors larger than 5 cm are risk factors for peritoneal recurrence (OR:2.88, p = 0.012). Positive lymph nodes were related to distant metastasis (OR:9.15, p = 0.040), and lymphatic invasion for locoregional recurrence (OR:3.81, p = 0.028).ConclusionAEGJ is associated with high rates of early recurrence. 相似文献
68.
André Luís Conde Watanabe Mateus Silva Feijó Vinícius Paulo Lima de Menezes Mayara Regina Galdino-Vasconcelos Jorge Luis Salinas Caballero Gustavo Ferreira Fernando Jorge Natália Trevizoli Luiz Gustavo Diaz Priscila Brizolla de Campos Gabriel Cajá Raquel Ullmann Ana Virgínia Figueira Tiago Morato Adriano Moraes Juan Rafael Branez Pereira Marcelo Perosa 《Transplantation proceedings》2021,53(1):73-82
IntroductionLiver transplantation is the standard treatment for end-stage liver disease. Brazil holds the third highest number of liver transplants performed per year, but center maldistribution results in high discrepancies in accessing this treatment. In 2012, an interstate partnership successfully implemented a new liver transplantation program in the middle west of Brazil. Here, we report the results of the first 500 liver transplants performed in this new program and discuss the impacts of a new transplant center in regional transplantation dynamics.MethodsWe reviewed data from the first 500 consecutive deceased donor liver transplants performed in the new program during an 8-year period. We analyzed data on patients’ clinical and demographic profiles, postoperative outcomes, and graft and recipient survival rates. Univariate survival analysis was conducted using log-rank tests to compare the groups.ResultsAlmost half (48%) of the procured organs and 40% of the recipients transplanted in our center were from outside our state. Recipient 30-day mortality was 9%. Overall recipient survival at 1 year and 5 years was 85% and 80%, respectively. Mortality was significantly associated with higher Model for End-Stage Liver Disease (P < .001) but not with the presence of hepatocellular carcinoma (P = .795).DiscussionThe new transplantation program treated patients from different regions of Brazil and became the reference center in liver transplantation for the middle west region. Despite the recent implementation, our outcomes are comparable to experienced centers around the world. This model can inspire the creation of new transplantation programs aiming to democratize access to liver transplantation nationwide. 相似文献
69.
Rabea Asleh Hilmi Alnsasra Amir Lerman Alexandros Briasoulis Naveen L. Pereira Brooks S. Edwards Takumi Toya John M. Stulak Alfredo L. Clavell Richard C. Daly Sudhir S. Kushwaha 《American journal of transplantation》2021,21(2):626-635
We have previously described the use of sirolimus (SRL) as primary immunosuppression following heart transplantation (HT). The advantages of this approach include attenuation of cardiac allograft vasculopathy (CAV), improvement in glomerular filtration rate (GFR), and reduced malignancy. However, in some patients SRL may cause significant proteinuria. We sought to investigate the prognostic value of proteinuria after conversion to SRL. CAV progression and adverse clinical events were studied. CAV progression was assessed by measuring the Δ change in plaque volume (PV) and plaque index (PI) per year using coronary intravascular ultrasound. Proteinuria was defined as Δ urine protein ≥300 mg/24 h at 1 year after conversion to SRL. Overall, 137 patients were analyzed (26% with proteinuria). Patients with proteinuria had significantly lower GFR (P = .005) but similar GFR during follow-up. Delta PV (P < .001) and Δ PI (P = .001) were significantly higher among patients with proteinuria after adjustment for baseline characteristics. Multivariate Cox regression analysis showed higher all-cause mortality (hazard ratio 3.8; P = .01) with proteinuria but similar risk of CAV-related events (P = .61). Our results indicate that proteinuria is a marker of baseline renal dysfunction, and that HT recipients who develop proteinuria after conversion to SRL have less attenuation of CAV progression and higher mortality risk. 相似文献
70.
Thainá Gattermann Pereira RD MS Júlia Lima RD Flávia Moraes Silva RD PhD 《JPEN. Journal of parenteral and enteral nutrition》2022,46(5):977-996
Impaired nutrition status is recognized as a risk factor for worse clinical outcomes in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to investigate how undernutrition is diagnosed, its prevalence, and whether there is an association between this condition and clinical outcomes in patients with COPD. The search for this systematic review of observational studies (PROSPERO: CRD42020191888) was performed in the PubMed, Embase, and Scopus databases, with no date or language restrictions. The studies had to report data on the diagnosis of undernutrition and its association with mortality, exacerbation, length of hospital stay, or quality of life in adult patients with COPD. A meta-analysis with a random-effects model was performed to combine data. Forty-nine studies were included (20 of them classified as having a low risk of bias), and the most common diagnostic method of undernutrition was body mass index (BMI) (n = 36). The pooled prevalence of undernutrition was equal to 20% (95% CI, 0.15–0.25; I² = 100%), and it was associated with mortality (risk ratio = 1.97; 95% CI, 1.55–2.50; I² = 98%), exacerbation (risk ratio = 1.73; 95% CI, 1.03–2.91; I² = 96%), and poorer quality of life (mean difference = 8.25; 95% CI, 5.40–11.10; I² = 79%). For all outcomes, the certainty of evidence was very low. In conclusion, undernutrition is prevalent and is associated with poorer outcomes in patients with COPD. However, undernutrition is mainly diagnosed by BMI, which underreports its prevalence, and the certainty of the evidence is very low. 相似文献