全文获取类型
收费全文 | 795篇 |
免费 | 47篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 20篇 |
妇产科学 | 18篇 |
基础医学 | 141篇 |
口腔科学 | 17篇 |
临床医学 | 149篇 |
内科学 | 152篇 |
皮肤病学 | 10篇 |
神经病学 | 31篇 |
特种医学 | 7篇 |
外科学 | 79篇 |
综合类 | 4篇 |
预防医学 | 105篇 |
眼科学 | 9篇 |
药学 | 52篇 |
中国医学 | 1篇 |
肿瘤学 | 54篇 |
出版年
2023年 | 15篇 |
2022年 | 13篇 |
2021年 | 24篇 |
2020年 | 22篇 |
2019年 | 31篇 |
2018年 | 23篇 |
2017年 | 29篇 |
2016年 | 20篇 |
2015年 | 24篇 |
2014年 | 18篇 |
2013年 | 55篇 |
2012年 | 37篇 |
2011年 | 56篇 |
2010年 | 20篇 |
2009年 | 29篇 |
2008年 | 40篇 |
2007年 | 59篇 |
2006年 | 60篇 |
2005年 | 41篇 |
2004年 | 42篇 |
2003年 | 33篇 |
2002年 | 43篇 |
2001年 | 3篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1963年 | 3篇 |
1961年 | 2篇 |
1956年 | 1篇 |
排序方式: 共有851条查询结果,搜索用时 31 毫秒
841.
Regional gas exchange and cellular metabolic activity in ventilator-induced lung injury 总被引:5,自引:0,他引:5
Musch G Venegas JG Bellani G Winkler T Schroeder T Petersen B Harris RS Melo MF 《Anesthesiology》2007,106(4):723-735
BACKGROUND: Alveolar overdistension and repetitive derecruitment-recruitment contribute to ventilator-induced lung injury (VILI). The authors investigated (1) whether inflammatory cell activation due to VILI was assessable by positron emission tomography and (2) whether cell activation due to dynamic overdistension alone was detectable when other manifestations of VILI were not yet evident. METHODS: The authors assessed cellular metabolic activity with [(18)F]fluorodeoxyglucose and regional gas exchange with [(13)N]nitrogen. In 12 sheep, the left ("test") lung was overdistended with end-inspiratory pressure of 50 cm H(2)O for 90 min, while end-expiratory derecruitment of this lung was either promoted with end-expiratory pressure of -10 cm H(2)O in 6 of these sheep (negative end-expiratory pressure [NEEP] group) or prevented with +10 cm H(2)O in the other 6 (positive end-expiratory pressure [PEEP] group) to isolate the effect of overdistension. The right ("control") lung was protected from VILI. RESULTS: Aeration decreased and shunt fraction increased in the test lung of the NEEP group. [(18)F]fluorodeoxyglucose uptake of this lung was higher than that of the control lung and of the test lung of the PEEP group, and correlated with neutrophil count. When normalized by tissue fraction to account for increased aeration of the test lung in the PEEP group, [(18)F]fluorodeoxyglucose uptake was elevated also in this group, despite the fact that gas exchange had not yet deteriorated after 90 min of overdistension alone. CONCLUSION: The authors could detect regional neutrophil activation in VILI even when end-expiratory derecruitment was prevented and impairment of gas exchange was not evident. Concomitant end-expiratory derecruitment converted this activation into profound inflammation with decreased aeration and regional shunting. 相似文献
842.
BACKGROUND: An increased prevalence of irritable bowel syndrome (IBS) and disturbances in cardiac and blood pressure reflexes have been described in patients with Crohn's disease (CD) and ulcerative colitis (UC). These features could be due to abnormalities in the gastrointestinal neurotransmission. The aims of this study were to examine whether histopathologic changes in the enteric nervous system correlate with disturbances in cardiac and blood pressure reflexes and the occurrence of IBS- and dyspepsia-like symptoms in these patients. METHODS: Thirty patients with CD and UC with bowel resection were examined by deep-breathing and orthostatic tests. The resection specimens were evaluated histologically regarding visceral neuro- or myopathy. All medical records were studied for treatment and clinical course. RESULTS: Ganglioneuritis was observed in 11 of 19 patients with CD and in 5 of 11 with UC. Only patients with CD had ganglioneuritis in the small intestine. Moreover, in CD the interstitial cells of Cajal (ICCs) in the small bowel showed atrophy and vacuolar degeneration, along with a reduced number of cells (P = 0.005). In UC the colonic ICCs were hyperplastic (P = 0.05) without signs of degeneration. The indices of deep-breathing and orthostatic tests were impaired, except in CD with ganglioneuritis, who showed normal test values. There were no correlations between histopathologic alterations versus IBS and dyspepsia. CONCLUSIONS: Visceral ganglioneuritis and pathologic ICCs were observed in patients with CD and UC. However, these histopathologic abnormalities could not be related to the clinical or autonomic features of the disease. 相似文献
843.
Jönsson EG Saetre P Edman-Ahlbom B Sillén A Gunnar A Andreou D Agartz I Sedvall G Hall H Terenius L 《Journal of neural transmission (Vienna, Austria : 1996)》2008,115(12):1695-1699
Brain-derived neurotrophic factor (BDNF) has been shown to influence monoamine transmitter synthesis, metabolism and release.
We investigated possible relationships between four BDNF gene polymorphisms and cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid
(HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in healthy volunteers (n = 132). All BDNF polymorphisms (270 C/T, −633 T/A, Val66Met, and 11757 G/C) were associated with MHPG (P < 0.02), but not with 5-HIAA and HVA concentrations. At a second clinical investigation 8–20 years after CSF sampling 30%
of the subjects had experienced various psychiatric disorders. Development of a psychiatric disorder was predicted by low
5-HIAA concentrations (P = 0.01). The results suggest that BDNF gene variation participates in regulation of norepinephrine turnover rates in the central nervous system of human subjects. 相似文献
844.
Alteration of amino acid and biogenic amine metabolism in hepatobiliary cancers: Findings from a prospective cohort study
下载免费PDF全文
![点击此处可从《International journal of cancer. Journal international du cancer》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Magdalena Stepien Talita Duarte‐Salles Veronika Fedirko Anne Floegel Dinesh Kumar Barupal Sabina Rinaldi David Achaintre Nada Assi Anne Tj?nneland Kim Overvad Nadia Bastide Marie‐Christine Boutron‐Ruault Gianluca Severi Tilman Kühn Rudolf Kaaks Krasimira Aleksandrova Heiner Boeing Antonia Trichopoulou Christina Bamia Pagona Lagiou Calogero Saieva Claudia Agnoli Salvatore Panico Rosario Tumino Alessio Naccarati H. B. Bueno‐de‐Mesquita Petra H. Peeters Elisabete Weiderpass J. Ramón Quirós Antonio Agudo María‐José Sánchez Miren Dorronsoro Diana Gavrila Aurelio Barricarte Bodil Ohlsson Klas Sj?berg M?rten Werner Malin Sund Nick Wareham Kay‐Tee Khaw Ruth C. Travis Julie A. Schmidt Marc Gunter Amanda Cross Paolo Vineis Isabelle Romieu Augustin Scalbert Mazda Jenab 《International journal of cancer. Journal international du cancer》2016,138(2):348-360
Perturbations in levels of amino acids (AA) and their derivatives are observed in hepatocellular carcinoma (HCC). Yet, it is unclear whether these alterations precede or are a consequence of the disease, nor whether they pertain to anatomically related cancers of the intrahepatic bile duct (IHBC), and gallbladder and extrahepatic biliary tract (GBTC). Circulating standard AA, biogenic amines and hexoses were measured (Biocrates AbsoluteIDQ‐p180Kit) in a case‐control study nested within a large prospective cohort (147 HCC, 43 IHBC and 134 GBTC cases). Liver function and hepatitis status biomarkers were determined separately. Multivariable conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (OR; 95%CI) for log‐transformed standardised (mean = 0, SD = 1) serum metabolite levels and relevant ratios in relation to HCC, IHBC or GBTC risk. Fourteen metabolites were significantly associated with HCC risk, of which seven metabolites and four ratios were the strongest predictors in continuous models. Leucine, lysine, glutamine and the ratio of branched chain to aromatic AA (Fischer's ratio) were inversely, while phenylalanine, tyrosine and their ratio, glutamate, glutamate/glutamine ratio, kynurenine and its ratio to tryptophan were positively associated with HCC risk. Confounding by hepatitis status and liver enzyme levels was observed. For the other cancers no significant associations were observed. In conclusion, imbalances of specific AA and biogenic amines may be involved in HCC development. 相似文献
845.
Paula Jakszyn Ana Fonseca‐Nunes Leila Lujan‐Barroso Núria Aranda Mónica Tous Victoria Arija Amanda Cross H. B Bueno‐de‐Mesquita Elisabete Weiderpass Tilman Kühn Rudolf Kaaks Klas Sj?berg Bodil Ohlsson Rosario Tumino Domenico Palli Fulvio Ricceri Francesca Fasanelli Vittorio Krogh Amalia Mattiello Mazda Jenab Marc Gunter Aurora Perez‐Cornago Kay‐Tee Khaw Anne Tj?nneland Anja Olsen Kim Overvad Antonia Trichopoulou Eleni Peppa Effie Vasilopoulou Heiner Boeing Emilio Sánchez‐Cantalejo José María Huerta Miren Dorronsoro Aurelio Barricarte José Maria Quirós Petra H. Peeters Antonio Agudo 《International journal of cancer. Journal international du cancer》2017,141(5):945-951
Hepcidin is the main regulator of iron homeostasis and dysregulation of proteins involved in iron metabolism has been associated with tumorogenesis. However, to date, no epidemiological study has researched the association between hepcidin levels and gastric cancer risk. To further investigate the relationship between hepcidin levels and gastric cancer risk, we conducted a nested case‐control study (EURGAST) within the multicentric European Prospective Investigation into Cancer and Nutrition study. The study included 456 primary incident gastric adenocarcinoma cases and 900 matched controls that occurred during an average of 11 years of follow‐up. We measured serum levels of hepcidin‐25, iron, ferritin, transferrin and C‐reactive protein. Odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of gastric cancer by hepcidin levels were estimated from multivariable conditional logistic regression models. Mediation effect of the ferritin levels on the hepcidin‐gastric cancer pathway was also evaluated. After adjusting for relevant confounders, we observed a statistically significant inverse association between gastric cancer and hepcidin levels (OR 5 ng/l = 0.96, 95% CI = 0.93–0.99). No differences were found by tumor localization or histological type. In mediation analysis, we found that the direct effect of hepcidin only represents a nonsignificant 38% (95% CI: ?69%, 91%). In summary, these data suggest that the inverse association of hepcidin levels and gastric cancer risk was mostly accounted by ferritin levels. Further investigation including repeated measures of hepcidin is needed to clarify their role in gastric carcinogenesis. 相似文献
846.
Dennis Zetner Claus Kamby Sengül Gülen Camilla Christophersen Cecilie B. Paulsen Emily Piga Bodil Hoffmeyer Faisal Mahmood Jacob Rosenberg 《Journal of pineal research》2023,74(1):e12840
The aim of this double-blind, placebo-controlled, randomized study was to investigate whether topical melatonin administered during radiation therapy could increase the quality of life in patients with primary breast cancer. Patients were followed from the first radiation fraction until 3 weeks after the last. The patients applied 1 g of cream to the irradiated area of the skin twice daily, consisting of either 25 mg/g melatonin and 150 mg/g dimethyl sulfoxide, or a placebo cream. Outcomes were the European Organisation for Research and Treatment of Cancer's quality-of-life questionnaires for breast cancer (QLQ-C30 and QLQ-BR23) on the last day of radiation therapy. As a secondary outcome, we evaluated the breast symptom (BS) scores over the entire duration of the trial in a repeated measures linear model. We included 65 patients and had 17 drop-outs, thus totaling 26 and 22 patients in the melatonin and placebo groups, respectively. BS scores on the last day of radiation did not differ between groups (p = .333). However, the linear model analyzing BS for the entire duration showed that melatonin significantly decreased the symptoms (p = .001). There was no difference in the BS score on the last day of radiation, however, we found that the patients in the melatonin group had significantly lower BS scores over the entire duration of the trial. 相似文献
847.
848.
849.
850.