全文获取类型
收费全文 | 1357篇 |
免费 | 76篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 22篇 |
妇产科学 | 27篇 |
基础医学 | 180篇 |
口腔科学 | 3篇 |
临床医学 | 105篇 |
内科学 | 433篇 |
皮肤病学 | 21篇 |
神经病学 | 203篇 |
特种医学 | 23篇 |
外科学 | 115篇 |
综合类 | 4篇 |
预防医学 | 109篇 |
眼科学 | 4篇 |
药学 | 90篇 |
肿瘤学 | 98篇 |
出版年
2024年 | 3篇 |
2023年 | 26篇 |
2022年 | 47篇 |
2021年 | 53篇 |
2020年 | 42篇 |
2019年 | 44篇 |
2018年 | 52篇 |
2017年 | 35篇 |
2016年 | 49篇 |
2015年 | 55篇 |
2014年 | 57篇 |
2013年 | 82篇 |
2012年 | 121篇 |
2011年 | 93篇 |
2010年 | 55篇 |
2009年 | 49篇 |
2008年 | 88篇 |
2007年 | 83篇 |
2006年 | 84篇 |
2005年 | 76篇 |
2004年 | 80篇 |
2003年 | 60篇 |
2002年 | 56篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1444条查询结果,搜索用时 15 毫秒
21.
Nerattini Matilde Rubino Federica Arnone Annachiara Polito Cristina Mazzeo Salvatore Lombardi Gemma Puccini Giulia Nacmias Benedetta De Cristofaro Maria Teresa Sorbi Sandro Pupi Alberto Sciagr Roberto Bessi Valentina Berti Valentina 《Neurological sciences》2022,43(4):2469-2480
Neurological Sciences - Alzheimer’s disease (AD) diagnosis can be hindered by amyloid biomarkers discordances. We aim to interpret discordances between amyloid positron emission tomography... 相似文献
22.
Benedetta Miglino MD Rossana Tiberio MD Stefano Astolfi MD Francesca Graziola MD Paolo Boggio MD Monica Leutner MD Guido Valente MD Roberto Franchini MD Enrico Colombo MD 《The breast journal》2016,22(3):339-341
Basal cell carcinoma (BCC) is a common skin cancer worldwide. However, BCC of the nipple and areola complex is rare. Men are more affected than women. Most of the cases were treated with simple excision. We report a case of BCC of the right nipple–areola complex in a 75‐year‐old man, treated with Mohs surgery and simple mastectomy. 相似文献
23.
Cecchi C Fiorillo C Baglioni S Pensalfini A Bagnoli S Nacmias B Sorbi S Nosi D Relini A Liguri G 《Neurobiology of aging》2007,28(6):863-876
Much experimental evidence suggests that an imbalance in cellular redox status is a major factor in the pathogenesis of Alzheimer's disease (AD). Our previous data showed a marked increase in membrane lipoperoxidation in primary fibroblasts from familial AD (FAD) patients. In the present study, we demonstrate that when oligomeric structures of Abeta 1-40 and Abeta 1-42 are added to the culture media, they accumulate quicker near the plasma membrane, and are internalized faster and mostly in APPV717I fibroblasts than in age-matched healthy cells; this results in an earlier and sharper increase in the production of reactive oxygen species (ROS). Higher ROS production leads in turn to an increase in membrane oxidative-injury and significant impairment of cellular antioxidant capacity, giving rise to apoptotic cascade activation and finally to a necrotic outcome. In contrast, healthy fibroblasts appear more resistant to amyloid oxidative-attack, possibly as a result of their plasma membrane integrity and powerful antioxidant capacity. Our data are consistent with increasing evidence that prefibrillar aggregates, compared to mature fibrils, are likely the more toxic species of the peptides. These findings provide compelling evidence that cells bearing increased membrane lipoperoxidation are more susceptible to aggregate toxicity as a result of their reduced ability to counteract amyloid oligomeric attack. 相似文献
24.
Influence of circadian rhythm on mortality after myocardial infarction: data from a prospective cohort of emergency calls 总被引:1,自引:0,他引:1
Manfredini R Boari B Bressan S Gallerani M Salmi R Portaluppi F Mehta RH 《The American journal of emergency medicine》2004,22(7):555-559
Myocardial infarction (MI) occurs more frequently in the morning as a result of the concomitant unfavorable timing of several physiological parameters and/or biochemical conditions. However, little is known about the possible influence of this circadian pattern on prognosis. To evaluate whether the time of symptom onset could potentially influence mortality from acute MI, this prospective study considered all consecutive MIs admitted to the ED of Ferrara, Italy, after a call to the Emergency Coordinating Unit from January 1, 1998, to December 31, 2001. The total sample consisted of 442 MIs (mean age, 68.7 years; males, 72%). Eighty patients (males, 82.5%) died in the ED; the remaining 362 were admitted to the hospital. Of these, 50 (males, 60%) died during their hospital stay. Based on the timing of their symptom onset, cases were categorized both into 24 1-hour intervals and four 6-hour intervals (midnight to 5:59 am, 6:00 am to 11:59 am, noon to 5:59 pm, and 6:00 pm to 11:59 pm), and the circadian distributions of fatal versus nonfatal MIs were compared. The circadian variation of MI peaked between 6:00 am and noon (P < .001), and in this period, there was a trend toward a higher frequency of fatal cases (41.5% vs. 35.2%; chi(2) = 1.911, P = .167). To verify whether this higher frequency of fatal events in the morning hours could be related to possible higher severity of cases observed in that hours, a further separate analysis considering age, infarct site, and peak levels of MB was made. Again, no significant temporal differences among the four 6-hour intervals were found between fatal and nonfatal Mis, although a trend toward older age was observed in morning MIs. Not only the frequency, but also the mortality, of acute MI could be increased in the morning hours. This could be of practical interest for emergency doctors and could have significant implications for acute treatment, because several studies have reported a lowered efficacy of thrombolytic drugs in the morning hours. 相似文献
25.
26.
27.
Vascular endothelial growth factor, left ventricular dysfunction and mortality in hemodialysis patients 总被引:1,自引:0,他引:1
Mallamaci F Benedetto FA Tripepi G Cutrupi S Pizzini P Stancanelli B Seminara G Bonanno G Rapisarda F Fatuzzo P Malatino LS Zoccali C 《Journal of hypertension》2008,26(9):1875-1882
OBJECTIVES: Vascular endothelial growth factor induces nitric oxide-dependent angiogenic effects and participates in the inflammatory response. This cytokine is over-expressed in the myocardium in experimental models of pressure overload and renal mass ablation, and vascular endothelial growth factor is increased in end-stage renal disease. We investigated the relationship between vascular endothelial growth factor, left ventricular function (by midwall fractional shortening) and mortality in a prospective cohort study in 228 hemodialysis patients. RESULTS: Serum vascular endothelial growth factor concentration was associated directly with interleukin-6 and tumor necrosis factor-alpha (P < 0.01) and inversely with albumin (P = 0.007) but was independent of the endogenous inhibitor of nitric oxide synthesis, asymmetric dimethylarginine. Vascular endothelial growth factor was inversely related with midwall fractional shortening (P = 0.002) and predicted mortality (P = 0.02). In multivariate analyses testing the involvement of this angiogenic cytokine in left ventricular dysfunction and death, these links remained substantially unmodified after adjustment for Framingham risk factors, risk factors peculiar to end-stage renal disease (Hb, Ca, P) and previous cardiovascular complications. However, these links became weaker and not significant when biomarkers of inflammation and asymmetric dimethylarginine were sequentially introduced into the multivariate models. In crude and adjusted analyses, left ventricular function was lowest in patients who displayed both high vascular endothelial growth factor and high asymmetric dimethylarginine, intermediate in patients with either high vascular endothelial growth factor or high asymmetric dimethylarginine and highest in those with low asymmetric dimethylarginine and low vascular endothelial growth factor (P = 0.001). CONCLUSION: Vascular endothelial growth factor is associated with left ventricular systolic dysfunction and mortality in hemodialysis patients. Vascular endothelial growth factor appears to be in the pathway whereby inflammation and nitric oxide inhibition lead to cardiomyopathy and death in hemodialysis patients. 相似文献
28.
Lugoboni F Migliozzi S Mezzelani P Pajusco B Ceravolo R Quaglio G 《Scandinavian journal of infectious diseases》2004,36(2):131-133
In the Western world, the population at the highest risk of HBV infection is probably that of illicit drug users (DUs). Since 1985, 1 Public Health Centre for Drug Users (PHCDU), in north-eastern Italy, has been asking all heroin DUs, whether in treatment or not, to undergo screening for HIV, HBV and, since 1989, for HCV infection. Since 1988 the Centre has proposed HBV vaccination to all patients who were negative for all HBV markers. From 1985 to 2001 895 heroin DUs were screened, 726 males and 169 females. 442 (49.4%) were negative to HBV markers at the first control and 72.4% received at least 1 dose of the vaccine. 320 DUs were vaccinated and a total of 995 doses of recombinant vaccine were administered. The anti-HBc antibody appeared in 2 vaccinated patients out of 258 DUs undergoing controls, while 13 seroconversions for anti-HBc occurred in 45 DUs who had refused to be vaccinated. On the basis of these results, HBV vaccination of DUs can be strongly recommended. Vaccination showed a good adherence in a population difficult to treat and can have a leading role in reducing HBV infection in DUs and their contacts. 相似文献
29.
Nappi RE Sances G Brundu B Ghiotto N Detaddei S Biancardi C Polatti F Nappi G 《Neuroendocrinology》2003,78(1):52-60
To assess the neuroendocrine correlates of menstrual status migrainosus (MSM) and menstrual migraine (MM), we evaluated the prolactin (PRL) and cortisol responses to the direct central serotoninergic (5-HT) agonist meta-chlorophenylpiperazine (m-CPP) administered orally (0.5 mg/kg) during the follicular (FP: +6, +8) and luteal phases (LP: -4, -6) of the same menstrual cycle. Ten women with MSM (migraine attacks occurring within 2 days of the onset of menstrual bleeding but lasting more than 72 h) and 9 women with MM (migraine occurring within 2 days of the onset of menstrual bleeding with a typical duration of attacks) were studied. Six healthy women served as controls. Blood samples were taken at times -30, 0 and every 30 min over 4 h. Statistical analysis was performed using MANOVA followed by Duncan's post hoc comparisons. We found that the PRL response to the m-CPP test was significantly blunted in MSM compared with MM and controls in both phases of the menstrual cycle (F = 4.6; p < 0.001). Indeed, the PRL area under the curve (AUC) after m-CPP was higher in both MM and controls compared with MSM (F = 12.7; p < 0.001). The m-CPP-induced cortisol response was absent in MSM compared with MM and controls in both FP and LP (F = 4.1; p < 0.001). On the other hand, the pattern of the plasma cortisol response to m-CPP was similar in MM and controls throughout the menstrual cycle. In addition, the basal plasma cortisol levels were significantly higher in MSM compared with controls (p < 0.001) and MM (p < 0.001) during FP, but not in LP, and progressively decreased over time. Thus, no significant effect of the menstrual cycle phase and diagnosis on the cortisol AUC was found, while a significant diagnosis effect (F = 25.6; p < 0.001) on %delta(max) plasma cortisol levels was evident and consistent with the lack of cortisol response to m-CPP in MSM during the FP and LP compared with MM and controls. A derangement in central 5-HT control of pituitary PRL, and even more so in cortisol release, is present in women with MSM, but not with MM, regardless of the phase of the menstrual cycle, suggesting the involvement of some 5-HT(1) and 5-HT(2) receptor subtypes in the occurrence of extremely severe migraine attacks triggered by menstruation. 相似文献
30.
Caterina Tatarelli Anna Lina Piccioni Luca Maurillo Virginia Naso Roberta Battistini Mariella D’Andrea Marianna Criscuolo Carolina Nobile Nicoletta Villivà Stefano Mancini Benedetta Neri Massimo Breccia Susanna Fenu Francesco Buccisano Maria Teresa Voso Roberto Latagliata Maria Antonietta Aloe Spiriti 《Annals of hematology》2014,93(8):1413-1420
Myelodysplastic syndromes (MDS) are common in elderly patients. Recombinant human erythro-poietin (rHuEPO) has been widely used to treat anemia in lower risk MDS patients, but few data are known about rHuEPO treatment in the very elderly patient group. In order to investigate the role of rHuEPO treatment in terms of response, overall survival (OS), and toxicity in a very elderly MDS patient group, 93 MDS patients treated with rHuEPO when aged ≥80 years were selected among MDS cases enrolled in a retrospective multicenter study by the cooperative group Gruppo Romano Mielodisplasie (GROM) from Jan 2002 to Dec 2010. At baseline, median age was 82.7 (range 80–99.1) with a median hemoglobin (Hb) level of 9 g/dl (range 6–10.8). The initial dose of rHuEPO was standard (epoetin alpha 40,000 IU/week or epoetin beta 30,000 IU/week) in 59 (63.4 %) pa-tients or high in 34 (36.6 %) (epoetin alpha 80,000 IU/week) patients. We observed an erythroid response (ER) in 59 (63.4 %) patients. No thrombotic event was reported. Independent predictive factors for ER were low transfusion requirement before treatment (p?=?0.004), ferritin <200 ng/ml (p?=?0.017), Hb >8 g/dl (p?=?0.034), and a high-dose rHuEPO treatment (p?=?0.032). Median OS from rHuEPO start was 49.3 months (95 % CI 27.5–68.4) in responders versus 30.6 months (95 % CI 7.3–53.8) in resistant patients (p?=?0.185). In conclusion, rHuEPO treatment is safe and effective also in the very elderly MDS patients. However, further larger studies are warranted to evaluate if EPO treatment could be worthwhile in terms of quality of life and cost-efficacy in very old patients. 相似文献