全文获取类型
收费全文 | 5265篇 |
免费 | 307篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 196篇 |
妇产科学 | 85篇 |
基础医学 | 620篇 |
口腔科学 | 461篇 |
临床医学 | 416篇 |
内科学 | 1201篇 |
皮肤病学 | 89篇 |
神经病学 | 325篇 |
特种医学 | 345篇 |
外科学 | 556篇 |
综合类 | 25篇 |
预防医学 | 555篇 |
眼科学 | 85篇 |
药学 | 347篇 |
中国医学 | 26篇 |
肿瘤学 | 209篇 |
出版年
2023年 | 43篇 |
2022年 | 134篇 |
2021年 | 176篇 |
2020年 | 133篇 |
2019年 | 147篇 |
2018年 | 192篇 |
2017年 | 134篇 |
2016年 | 123篇 |
2015年 | 193篇 |
2014年 | 247篇 |
2013年 | 243篇 |
2012年 | 359篇 |
2011年 | 425篇 |
2010年 | 264篇 |
2009年 | 184篇 |
2008年 | 279篇 |
2007年 | 291篇 |
2006年 | 220篇 |
2005年 | 225篇 |
2004年 | 162篇 |
2003年 | 131篇 |
2002年 | 118篇 |
2001年 | 91篇 |
2000年 | 85篇 |
1999年 | 72篇 |
1998年 | 64篇 |
1997年 | 77篇 |
1996年 | 75篇 |
1995年 | 49篇 |
1994年 | 59篇 |
1993年 | 58篇 |
1992年 | 45篇 |
1991年 | 41篇 |
1990年 | 28篇 |
1989年 | 50篇 |
1988年 | 52篇 |
1987年 | 35篇 |
1986年 | 39篇 |
1985年 | 43篇 |
1984年 | 20篇 |
1983年 | 32篇 |
1982年 | 21篇 |
1981年 | 19篇 |
1980年 | 21篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1977年 | 14篇 |
1976年 | 14篇 |
1975年 | 20篇 |
1971年 | 5篇 |
排序方式: 共有5592条查询结果,搜索用时 45 毫秒
101.
The widespread assumption that cytoplasts generated from human polymorphonuclear leukocytes (PMNs) are vesicles consisting solely of cytoplasm surrounded by plasma membrane and devoid of granule activity remains to be tested. PMN cytoplasts were prepared by centrifugation of intact cells on a Ficoll step gradient in the presence of cytochalasin B. Two granule membrane markers, Mol, a fluorometrically detectable antigen, and cytochrome b, both of which have been shown to translocate to the plasma membrane during granule release, were compared for their activity in cytoplasts and intact PMNs. We found that the amount of Mol detected on the plasma membrane of intact PMNs, as compared with other membrane markers (such as antigens LFA-1 and beta 2m), increased 1.6- fold upon exposure of PMNs to Ficoll plus cytochalasin B prior to centrifugation. Another twofold increase in Mol expression occurred upon cytoplast preparation. Release of the granule enzymes, vitamin B12- binding protein, and lysozyme were also followed and correlated well (r = .78 and .92) with the amount of Mol antigen present on the cell surface. Cytochrome b was also found to be higher (1.4-fold) on plasma membranes isolated from cytoplasts than on plasma membranes isolated from intact control cells. These results indicate that some fusion of granule membranes and plasma membranes occurred during treatment of PMNs with Ficoll plus cytochalasin b and during cytoplast preparation. 相似文献
102.
V Amato Neto A A Moreira G M Ferreira S A do Nascimento L Matsubara R Campos P L Pinto 《Revista do Instituto de Medicina Tropical de S?o Paulo》1990,32(3):185-188
With the objective of knowing adequately the spectrum of activity of albendazole against intestinal helminthiases, we made observations regarding hymenolepiasis caused by Hymenolepis nana. Two series of investigations were carried out: a) treatment of mice with single doses of either 25 or 50 mg/kg, repeated after ten days, using as controls animals treated with 25 mg/kg of praziquantel or not treated with any antiparasitic drugs; b) treatment of adults and children with 400 mg daily for three consecutive days, repeated after ten days. 相似文献
103.
Talmadge JE; Schneider M; Keller J; Ruscetti F; Longo D; Pennington R; Bowersox O; Tribble H 《Blood》1989,73(6):1458-1467
In a series of studies designed to extend our understanding of interleukin-2 (IL-2) and to study the effect of biologic response modifiers on bone marrow, we observed that administering recombinant human (rH) IL-2 to normal mice resulted in an increase in the frequency of colony-forming units-culture (CFU-C) in bone marrow. In addition, rH IL-2 was able to accelerate host recovery from cyclophosphamide (CTX)- or radiation-induced bone marrow depression and peripheral blood leukopenia. Not only can rH IL-2 accelerate, in a dose-dependent manner, the return of bone marrow, peripheral blood cellularity, and CFU-C frequency to normal levels following cytoreduction by CTX or irradiation, but it also significantly increases CFU-C frequency to greater than normal levels. Furthermore, rH IL-2 can significantly prolong survival of animals receiving a lethal dose of irradiation or CTX. Thus, multiple mechanisms are responsible for the synergistic therapeutic activity associated with rH IL-2 and CTX. rH IL-2 does not act only as an immunomodulatory agent in the presence or absence of suppressor T cells, but also accelerates host recovery from cytoreductive agents, resulting in decreased leukopenia and perhaps resistances to secondary infection. Thus, rH IL-2 plus chemotherapy may increase therapeutic activity against neoplastic disease, not only by adding immune stimulation to the direct antitumor effect of the drug but also by allowing delivery of higher, more effective doses of chemotherapy. 相似文献
104.
Peña E Moreira VF García S Urman J del Pozo D Miquel J 《Gastroenterologia y hepatologia》2000,23(8):389-391
We describe a case of chronic idiopathic pancreatitis associated with ulcerative colitis. Pancreatitis is a rare extra-intestinal manifestations of inflammatory bowel disease. Chronic idiopathic pancreatitis associated with ulcerative colitis are usually painless, without calcification, with stricture of the main pancreatic duct and with severe exocrine pancreatic insufficiency. 相似文献
105.
106.
Galectina-3 Associada a Formas Graves e Mortalidade em Longo Prazo em Pacientes com Doença de Chagas
Fbio Fernandes Carlos Henrique Valente Moreira Lea Campos Oliveira Marcela Souza-Basqueira Barbara Maria Ianni Claudia di Lorenzo Felix Jos Alvarez Ramires Luciano Nastari Edecio Cunha-Neto Antonio L. Ribeiro Renato Delascio Lopes Sheila M. Keating Ester Cerdeira Sabino Charles Mady 《Arquivos brasileiros de cardiologia》2021,116(2):248
Background The histopathological characteristics of Chagas disease (ChD) are: presence of myocarditis, destruction of heart fibers, and myocardial fibrosis. Galectin-3 (Gal-3) is a biomarker involved in the mechanism of fibrosis and inflammation that may be useful for risk stratification of individuals with ChD.Objectives We sought to evaluate whether high Gal-3 levels are associated with severe forms of Chagas cardiomyopathy (CC) and whether they are predictive of mortality.Methods We studied anti-T. cruzi positive blood donors (BD): Non-CC-BD (187 BD without CC with normal electrocardiogram [ECG] and left ventricular ejection fraction [LVEF]); CC-Non-Dys-BD (46 BD with CC with abnormal ECG but normal LVEF); and 153 matched serum-negative controls. This cohort was composed of 97 patients with severe CC (CC-Dys). We used Kruskall-Wallis and Spearman’s correlation to test hypothesis of associations, assuming a two-tailed p<0.05 as significant.Results The Gal-3 level was 12.3 ng/mL for Non-CC-BD, 12.0 ng/mL for CC-Non-Dys-BD, 13.8 ng/mL for controls, and 15.4 ng/mL for CC-Dys. LVEF<50 was associated with higher Gal-3 levels (p=0.0001). In our linear regression adjusted model, we found association between Gal-3 levels and echocardiogram parameters in T. cruzi-seropositive subjects. In CC-Dys patients, we found a significant association of higher Gal-3 levels (≥15.3 ng/mL) and subsequent death or heart transplantation in a 5-year follow-up (Hazard ratio – HR 3.11; 95%CI 1.21–8.04; p=0.019).Conclusions In ChD patients, higher Gal-3 levels were significantly associated with severe forms of the disease and more long-term mortality, which means it may be a useful means to identify high-risk patients. (Arq Bras Cardiol. 2021; 116(2):248-256) 相似文献
107.
The purpose of this research was to identify whether a certain set of drivers of satisfaction/perceived quality of healthcare (PQHC) could indirectly affect patients’ confidence/trust in the emergency department (ED).Patients were seen at an ED in the public hospital in Lisbon, Portugal between January and December 2016. Data were collected between May and November 2017, using a questionnaire, by mail or e-mail. The total sample size comprised 382 patients. The data analysis included structural equation modeling to test the conceptual model with specific drivers of satisfaction/PQHC (privacy; accessibility and availability; doctors; meeting expectations; waiting time for triage [perception]; waiting time to be called back by the doctor following examinations and/or tests [perception]; information about possible delays in receiving treatment/waiting times) and with the main outcome (confidence/trust in the ED) using path analysis.The analysis of the coefficients revealed that all the mediated paths are statistically significant (P ≤ .05). Although, altogether, the direct paths did not prove statistically significant (P > .05), the overall satisfaction with doctors (P ≤ .01) and meeting expectations (P = .01) can still directly explain the confidence/trust in the ED without the mediating role of satisfaction and PQHC. Hence, overall satisfaction with doctors and meeting expectations can influence, both directly and indirectly, confidence/trust in the ED. All other variables can only indirectly affect confidence/trust in the ED, either through PQHC or through satisfaction.Even though there are more variables that influence confidence/trust in the ED through PQHC (1)waiting time to be called back by the doctor following examinations and/or tests [perception]; 2) privacy; 3) accessibility and availability; 4) doctors; 5) meeting expectations than through satisfaction (1)waiting time for triage [perception]; 2) information about possible delays in receiving treatment/waiting times; 3) doctors; 4) meeting expectations), we observe the strongest contribution in the mediation model through satisfaction, which reveals its dominant role over PQHC. 相似文献
108.
Matheus Rassi Fernandes Ramos Henrique Turin Moreira Gustavo Jardim Volpe Minna Romano Benedito Carlos Maciel Andr Schmidt Anis Rassi Junior Jose Antnio Marin Neto 《Arquivos brasileiros de cardiologia》2021,116(1):68
BackgroundCardiomegaly on chest X-ray is an independent predictor of death in individuals with chronic Chagas cardiomyopathy (CCC). However, the correlation between increased cardiothoracic ratio (CTR) on chest X-ray and left ventricular end-diastolic diameter (LVEDD) on echocardiography is not well established in this population.ObjectivesTo assess the relationship between chest X-ray and LVEDD on echocardiography in patients with Chagas disease and its applicability to the Rassi score.MethodsRetrospective study on 63 Chagas disease outpatients who underwent chest X-ray and echocardiography. Cardiomegaly on chest X-ray was defined as a CTR>0.5. LVEDD was analyzed as a continuous variable. ROC curve was used to evaluate the ability of LVEDD in detecting cardiomegaly by chest X-ray, with a cut-off point defined by the highest sum of sensitivity and specificity.ResultsMedian age 61 years [interquartile range 48-68], 56% were women. CCC was detected in 58 patients, five patients had the indeterminate form of Chagas disease. Cardiomegaly was detected in 28 patients. The area under the ROC curve for LVEDD was 0.806 (95%CI: 0.692-0.919). The optimal cut-off for LVEDD was 60 mm (sensitivity = 64%, specificity = 89%). The use of LVEDD on echocardiography as a surrogate for CTR on chest X-ray changed the Rassi score values of 14 patients, with a reduction in the presumed risk in 10 of them.ConclusionLVEDD on echocardiography is an appropriate, highly specific parameter to distinguish between the presence and absence of cardiomegaly on chest X-ray in Chagas disease. (Arq Bras Cardiol. 2021; 116(1):68-74) 相似文献
109.
Glòria Fernández-Esparrach José Carlos Marín-Gabriel Pilar Díez Redondo Henar Núñez Enrique Rodríguez de Santiago Pedro Rosón Xavier Calvet Miriam Cuatrecasas Joaquín Cubiella Leticia Moreira M. Luisa Pardo López Ángeles Pérez Aisa José Miguel Sanz Anquela 《Gastroenterologia y hepatologia》2021,44(6):448-464
This position paper, sponsored by the Asociación Española de Gastroenterología [Spanish Association of Gastroenterology], the Sociedad Española de Endoscopia Digestiva [Spanish Gastrointestinal Endoscopy Society] and the Sociedad Española de Anatomía Patológica [Spanish Anatomical Pathology Society], aims to establish recommendations for performing an high quality upper gastrointestinal endoscopy for the screening of gastric cancer precursor lesions (GCPL) in low-incidence populations, such as the Spanish population. To establish the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We obtained a consensus among experts using a Delphi method. The document evaluates different measures to improve the quality of upper gastrointestinal endoscopy in this setting and makes recommendations on how to evaluate and treat the identified lesions. We recommend that upper gastrointestinal endoscopy for surveillance of GCPL should be performed by endoscopists with adequate training, administering oral premedication and use of sedation. To improve the identification of GCPL, we recommend the use of high definition endoscopes and conventional or digital chromoendoscopy and, for biopsies, NBI should be used to target the most suspicious areas of intestinal metaplasia. Regarding the evaluation of visible lesions, the risk of submucosal invasion should be evaluated with magnifying endoscopes and endoscopic ultrasound should be reserved for those with suspected deep invasion. In lesions amenable to endoscopic resection, submucosal endoscopic dissection is considered the technique of choice. 相似文献
110.
Henrique Turin Moreira Gustavo Jardim Volpe Uebe Chade Rezek Pedro Cunha de Mendona Gustavo Corrêa de Almeida Teixeira Bruno Moreira dos Santos Anna Paula Gonalves Olivieri Ana Julia Abbud Chierice Henrique Zanqueta Monteiro Natanael Mendes de Araújo Benedito Carlos Maciel Antonio Pazin Filho Andr Schmidt 《Arquivos brasileiros de cardiologia》2021,116(1):153