全文获取类型
收费全文 | 15027篇 |
免费 | 835篇 |
国内免费 | 148篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 321篇 |
妇产科学 | 223篇 |
基础医学 | 1709篇 |
口腔科学 | 377篇 |
临床医学 | 1293篇 |
内科学 | 4737篇 |
皮肤病学 | 179篇 |
神经病学 | 1478篇 |
特种医学 | 603篇 |
外科学 | 2138篇 |
综合类 | 26篇 |
预防医学 | 493篇 |
眼科学 | 132篇 |
药学 | 653篇 |
中国医学 | 9篇 |
肿瘤学 | 1543篇 |
出版年
2023年 | 126篇 |
2022年 | 213篇 |
2021年 | 409篇 |
2020年 | 283篇 |
2019年 | 346篇 |
2018年 | 407篇 |
2017年 | 329篇 |
2016年 | 403篇 |
2015年 | 427篇 |
2014年 | 594篇 |
2013年 | 806篇 |
2012年 | 1146篇 |
2011年 | 1204篇 |
2010年 | 662篇 |
2009年 | 686篇 |
2008年 | 1059篇 |
2007年 | 1123篇 |
2006年 | 1025篇 |
2005年 | 991篇 |
2004年 | 981篇 |
2003年 | 800篇 |
2002年 | 721篇 |
2001年 | 93篇 |
2000年 | 67篇 |
1999年 | 100篇 |
1998年 | 120篇 |
1997年 | 120篇 |
1996年 | 89篇 |
1995年 | 82篇 |
1994年 | 62篇 |
1993年 | 74篇 |
1992年 | 46篇 |
1991年 | 57篇 |
1990年 | 40篇 |
1989年 | 24篇 |
1988年 | 25篇 |
1987年 | 26篇 |
1986年 | 33篇 |
1985年 | 21篇 |
1984年 | 29篇 |
1983年 | 23篇 |
1982年 | 17篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1972年 | 7篇 |
1968年 | 7篇 |
1967年 | 10篇 |
1966年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
51.
Saviano MS Fundarò S Gelmini R Begossi G Perrone S Farinetti A Criscuolo M 《Surgery today》1999,29(2):174-177
(Received for publication on Apr. 28, 1997; accepted on May 15, 1998) 相似文献
52.
Dr. Carlo Merkel MD Angelo Gatta MD Marco Zoli MD Massimo Bolognesi MD Paolo Angeli MD Tiziana Iervese MD Giulio Marchesini MD Arturo Ruol MD 《Digestive diseases and sciences》1991,36(9):1197-1203
Seventy-eight patients with cirrhosis were prospectively followed for up to 20 months, on the average. At entry into the study, galactose elimination capacity, aminopyrine breath test, and ICG clearance were measured. At the end of the study, 27 patients had died. Univariate analysis using the Kaplan-Meier method showed that both quantitative liver function tests (galactose elimination capacity:P<0.025; aminopyrine breath test:P<0.001; ICG clearance:P<0.005) and common clinical and biochemical data (encephalopathy:P<0.001; ascites:P<0.001; serum bilirubin:P<0.005; serum albumin:P<0.001; prothrombin index:P<0.05) were significant predictors of survival. To investigate whether quantitative liver function tests could contribute to a better definition of the prognosis, once Pugh score had already been taken into account, a multiple regression analysis according to the Cox model was performed. Pugh score and galactose elimination capacity resulted in the only independent prognostic covariates. From them a prognostic index was calculated, and the model was validated in an additional sample of 70 patients investigated according to the same protocol. The contribution GEC gave to the assessment of overall prognosis over that obtained using the Pugh score was slight, as estimated by the statistical parameters of the Cox's model, but was significant as assessed by a ROC curve analysis (P=0.05). These data show that all quantitative liver function tests were predictors of survival in cirrhosis, and that the galactose elimination capacity added some new prognostic information to those already available using the Child-Turcotte-Pugh classification.This study was supported in part by a grant from the Italian Ministry of Education (National Project Liver Cirrhosis). Part of this study was presented at the 22nd Meeting of the European Society for Clinical Investigation, Graz, Austria, April 20–23, 1988. 相似文献
53.
Value of P-glycoprotein and clinicopathologic factors as the basis for new treatment strategies in high-grade osteosarcoma of the extremities. 总被引:8,自引:0,他引:8
Massimo Serra Katia Scotlandi Gemma Reverter-Branchat Stefano Ferrari Maria C Manara Stefania Benini Marina Incaprera Franco Bertoni Mario Mercuri Antonio Briccoli Gaetano Bacci Piero Picci 《Journal of clinical oncology》2003,21(3):536-542
PURPOSE: To evaluate the prognostic value of P-glycoprotein and clinicopathologic parameters in a large series of high-grade osteosarcoma (OS) patients treated at the Rizzoli Institute. PATIENTS AND METHODS: With the use of immunohistochemistry, P-glycoprotein was assessed in 149 patients with primary, nonmetastatic, high-grade OS who were homogeneously treated with chemotherapy protocols based on doxorubicin, high-dose methotrexate, and cisplatin and the addition of ifosfamide in the postoperative phase. RESULTS: P-glycoprotein positivity was found in 47 of 149 cases (32%) and was significantly associated with a higher incidence of relapse and a worse outcome, as was age younger than 12 years and tumor volume greater then 150 mL at diagnosis. Multivariate analysis further confirmed the prognostic value of these parameters, which all were independent adverse prognostic factors. Event-free survival and proportional hazards regression analyses confirmed that overexpression of P-glycoprotein at clinical onset is the most important adverse prognostic factor for high-grade OS patients treated with these chemotherapy protocols. CONCLUSION: Increased P-glycoprotein levels, together with tumor volume and age, should be taken into consideration to identify, at time of diagnosis, subgroups of OS patients with a higher risk of recurrence. This subgroup identification will constitute the basis for drawing individualized treatment protocols on the basis of risk evaluation, with the aim of using more aggressive chemotherapy, or combination chemotherapy with other adjuvants, only in those patients for which more aggressive regimens are strictly necessary and warranted. 相似文献
54.
Carlo Gambacorti-Passerini Massimo Zucchetti Domenico Russo Roberta Frapolli Magda Verga Silvia Bungaro Lucia Tornaghi Fabio Rossi Pietro Pioltelli Enrico Pogliani Daniele Alberti Gianmarco Corneo Maurizio D'Incalci 《Clinical cancer research》2003,9(2):625-632
PURPOSE: Imatinib (Glivec) is a potent inhibitor of bcr/abl, an oncogenic fusion protein that causes chronic myelogenous leukemia (CML). alpha1 acid glycoprotein (AGP) binds to imatinib with high affinity and inhibits imatinib activity in vitro and in vivo in an animal model. A pharmacokinetics analysis of imatinib was undertaken in CML patients. EXPERIMENTAL DESIGN: Imatinib plasma concentrations were measured in 19 CML patients treated with imatinib (400 or 600 mg/day). Five patients received a concomitant short-term course of clindamycin (CLI). RESULTS: A positive correlation between AGP and imatinib plasma levels was observed. CLI administration decreased imatinib plasma concentrations, evaluated as area under the curve (AUC) and peak concentrations (C(max)). The effects of a bolus of CLI was studied in three patients on imatinib 23 h after the last imatinib dose. Within 5-10 min in three of three cases, CLI caused a decrease in imatinib plasma concentrations of 2.6-, 2.7-, and 4.7-fold, respectively. In vitro experiments using fresh blasts from CML patients showed that AGP, at concentrations observed in the patients, decreased imatinib intracellular concentrations up to 10 times and blocked imatinib activity. The incubation with CLI restored imatinib intracellular concentrations and biological activity. CONCLUSION: AGP exerts significant effects of the pharmacokinetics, plasma concentrations, and intracellular distribution of imatinib in CML patients; these data indicate that plasma imatinib levels represent unreliable indicators of the cellular concentrations of this molecule. 相似文献
55.
56.
Fabio Scopesi Silvana Canini Cesare Arioni Massimo Mazzella Diego Gazzolo Pasquale B Lantieri Wanda Bonacci Giovanni Serra 《The journal of maternal-fetal & neonatal medicine》2006,19(6):343-346
BACKGROUND: Recently we demonstrated an increased 2,3-diphosphoglycerate (2,3-DPG) erythrocyte concentration in rat pups subjected to nucleotide-enriched artificial feeding. DESIGN: The present study was carried out to test the hypothesis that a possible increase in 2,3-DPG concentration can also be obtained in human neonates who are fed nucleotide-enriched formula. Preterm neonates born or referred to the neonatal intensive care unit of the G. Gaslini Hospital, Genoa University, with a gestational age >30 weeks and <37 weeks were enrolled in our randomized trial. Recruitment took place within 48-72 hours from birth. Only newborns of mothers deciding not to breast-feed were eligible to be randomized for the supplemented group (FN) or non-supplemented group (RF). Breast-fed newborns were considered the control group (C). The study window (for supplementation and blood samples) was restricted to the first two weeks following birth (from the 2nd (t1) to the 16th (t2) day of life). At the end of our study, only 21 neonates were eligible for statistical analysis. RESULTS: The stimulating action of dietary nucleotides on 2,3-DPG concentration failed to be demonstrated; increases in 2,3-DPG concentration that were observed in newborns fed with nucleotide supplemented formula (FN) were comparable to those observed in newborns fed with regular formula (RF) and breast-fed newborns. CONCLUSIONS: The EC recommendation for the amount of nucleotides allowed in formula milk does not seem to be high enough to have positive effects on 2,3-DPG synthesis. Whether this possible 'pharmacological' effect can be achieved by a higher intake of ingested nucleotides and/or a change in the proportions of single nucleotides contained in milk formulas remain interesting end points to be elucidated. 相似文献
57.
Risk management strategies in the postmarketing period : safety experience with the US and European bosentan surveillance programmes. 总被引:1,自引:0,他引:1
Eleanor S Segal Cecile Valette Laurence Oster Luc Bouley Catarina Edfjall Peter Herrmann Massimo Raineri Mary Kempff Saundra Beacham Cinda van Lierop 《Drug safety》2005,28(11):971-980
In view of the shortcomings of the current system for postmarketing drug surveillance that is based on voluntary spontaneous adverse drug reaction (ADR) reporting, new approaches are needed.We describe an approach involving a combination of limited distribution, patient and physician education, as well as a novel pharmaco-vigilance system that is capable of promoting the safe and adequate use of a new drug. Importantly, it provides the possibility of calculating true ADR occurrence rates, as the exposed population (denominator) and the number of patients with events (numerator) are known. These measures were taken for the oral dual endothelin ET(A)/ET(B) antagonist bosentan (Tracleer). In recent guidelines issued by the European Society of Cardiology, American College of Chest Physicians and the WHO, this drug is considered as first-line oral treatment for the treatment of pulmonary arterial hypertension, a devastating orphan disease associated with a poor prognosis. Bosentan was approved in 2001/2 on the basis of two pivotal studies that showed improved exercise capacity and haemodynamic parameters while delaying time to clinical worsening. Elevations in serum liver aminotransferase levels of >3 times the upper limit of normal were noted in 10.2% of patients (placebo-subtracted incidence). Therefore, liver function tests have to be performed on a regular basis. In addition, bosentan has potential as a teratogen.In the US, a controlled distribution network for bosentan (Tracleer) Access Program [T.A.P.]) and the development of a patient database to follow patients was set up. Accompanied by comprehensive physician and patient education programmes, T.A.P. was developed to provide a mechanism to assist with the primary risk management goals for bosentan therapy, namely pregnancy prevention and liver enzyme monitoring and prevention of hepatic injury.In Europe, the Tracleer) Excellence (TRAX PMS) database is a novel European non-interventional, prospective, internet-based surveillance system initiated by the manufacturer in cooperation with the European Medicines Agency. It collected potential safety signals associated with bosentan use including adverse events, elevations of liver aminotransferase levels, other abnormal laboratory values, death and hospitalisation. TRAX PMS has accrued 79% of all known patients in the EU and the data provide supportive 'real-life' evidence on the long-term safety of bosentan.The two different systems had similar goals and outcomes. The data received concerning thousands of patient-years of use have confirmed the clinical trial results regarding product safety and the favourable benefit/risk ratio of bosentan, especially with regard to known type A adverse events. The clinical monitoring algorithm has also been confirmed. In addition, no rare type B events were uncovered despite the increased reporting rate. These systems might serve as templates for future pharmaco-vigilance efforts regarding drugs that require particular safety attention. 相似文献
58.
59.
The European Food Safety Authority is currently evaluating the risks related to the presence of emerging mycotoxins in food and feeds. The aim of this study was to investigate the role of soil fertility, resulting from different nitrogen fertilization rates, on the contamination of regulated mycotoxins and emerging fungal metabolites in maize grains. The trial was carried out in the 2012–2013 growing seasons as part of a long-term (20-year) experimental platform area in North-West Italy, where five different N rates, ranging from 0 to 400 kg N ha−1, were applied to maize each year. Maize samples were analyzed by means of a dilute-and-shoot multi-mycotoxin LC-MS/MS method, and more than 25 of the most abundant mycotoxins and fungal metabolites were detected. Contamination by fumonisins and other fungal metabolites produced by Fusarium spp. of the section Liseola was observed to have increased in soils that showed a poor fertility status. On the other hand, an overload of nitrogen fertilization was generally associated with higher deoxynivalenol and zearalenone contamination in maize kernels, as well as a higher risk of other fungal metabolites produced by Fusarium spp. sections Discolor and Roseum. A balanced application of N fertilizer, in accordance with maize uptake, generally appears to be the best solution to guarantee an overall lower contamination by regulated mycotoxins and emerging fungal metabolites. 相似文献