全文获取类型
收费全文 | 833篇 |
免费 | 18篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 34篇 |
妇产科学 | 25篇 |
基础医学 | 91篇 |
口腔科学 | 9篇 |
临床医学 | 66篇 |
内科学 | 210篇 |
皮肤病学 | 20篇 |
神经病学 | 48篇 |
特种医学 | 52篇 |
外科学 | 141篇 |
综合类 | 2篇 |
预防医学 | 43篇 |
眼科学 | 36篇 |
药学 | 28篇 |
中国医学 | 2篇 |
肿瘤学 | 38篇 |
出版年
2023年 | 51篇 |
2022年 | 63篇 |
2021年 | 46篇 |
2020年 | 89篇 |
2019年 | 24篇 |
2018年 | 26篇 |
2017年 | 31篇 |
2016年 | 42篇 |
2015年 | 53篇 |
2014年 | 66篇 |
2013年 | 25篇 |
2012年 | 29篇 |
2011年 | 17篇 |
2010年 | 30篇 |
2009年 | 26篇 |
2008年 | 13篇 |
2007年 | 15篇 |
2006年 | 13篇 |
2005年 | 15篇 |
2004年 | 7篇 |
2003年 | 15篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 17篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 16篇 |
1995年 | 5篇 |
1994年 | 11篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1964年 | 1篇 |
1946年 | 1篇 |
排序方式: 共有851条查询结果,搜索用时 15 毫秒
161.
PurposeTo determine the diagnostic potential of Material Density (MD) iodine images in dual-energy CT (DECT) for the detection and characterization of hypervascular liver lesions compared to monenergetic 65 keV images, using MRI as the standard.Materials and methodsThe study complied with HIPAA guidelines and was approved by the institutional review board. Fifty-two patients (36 men, 16 women; age range, 29–87 years) with 236 hypervascular liver lesions (benign, n = 31; malignant, n = 205; mean diameter, 29.4 mm; range: 6–90.6 mm) were included. All of them underwent both contrast-enhanced single-source DECT and contrast-enhanced abdominal MRI within three months. Late arterial phase CT imaging was performed with dual energies of 140 and 80 kVp. Protocol A showed monoenergetic 65 keV images, and protocol B presented MD-iodine images. Three radiologists qualitatively evaluated randomized images, and lesion detection, characterization, and reader confidence were recorded. Liver-to-lesion ratio (LLR) and contrast-to-noise ratio (CNR) were assessed on protocol A, protocol B, and MRI. Paired t-tests were used to compare LLR, CNR, and the number of detected lesions.ResultsLLR was significantly increased in protocol B (2.8 ± 2.33) compared to protocol A (0.77 ± 0.55) and MRI (0.61 ± 0.66). CNR was significantly higher in protocol B (0.08 ± 0.04) compared to protocol A (0.01 ± 0.01) and MRI (0.01 ± 0.01). All three observers correctly identified more liver lesions using protocol B vs protocol A: 83.13% vs 63.64%, 84.57% vs 68.09%, and 79.37% vs 65.52%. There was no significant difference between the three observers in classification of a lesion as benign or malignant. However, higher diagnostic confidence was reported more frequently by the experienced radiologist when using protocol B vs protocol A (84.6% vs 75%).ConclusionMD-iodine images in DECT help to increase the conspicuity and detection of hypervascular liver lesions. 相似文献
162.
《Pediatric clinics of North America》2013,60(6):1475-1488
163.
164.
《结合医学学报(英文版)》2022,20(3):230-236
BackgroundConstipation is a common chronic bowel disorder with an incidence of more than 50% in the elderly population. Complementary and alternative medicine is a cost-effective and satisfactory treatment for constipation used widely by the elderly.ObjectiveThis study evaluates the efficacy of an herbal formula made from Foeniculum vulgare Mill. and Rosa damascena for the treatment of constipation in an elderly population and consequent changes to their quality of life.Design, setting, participants and interventionThis double-blind randomized active controlled clinical trial, with parallel group allocation ratio of 1:1, was conducted in a referral clinic in Afzalipour Hospital, affiliated to Kerman University of Medical Sciences in Kerman, Southeastern Iran. Individuals over 60 years of age, diagnosed with functional constipation (based on the Rome IV criteria), were included in this study. Participants received a sachet of 10 g F. vulgare and R. damascena (herbal formula group) or polyethylene glycol 4000 (PEG 4000 group) with a glass of warm water two times a day for 4 weeks and were followed up for 4 additional weeks.Main outcome measuresConstipation severity, stool consistency, and the quality of life were used as the primary outcomes. Drug side effects were used as a secondary outcome. The outcomes were assessed using the Constipation Assessment Scale, the Bristol Stool Form Scale, and the Patient Assessment of Constipation Quality of Life questionnaire.ResultsA total of 25 participants in each group completed the four-week treatment cycle and the eight-week follow-up. At the end of the four-week treatment cycle, all clinical outcomes had significant improvements in both groups (P < 0.05). The analysis of constipation severity (P < 0.001), stool consistency (P < 0.001), and the quality of life (P < 0.001) showed significant improvements with fewer side effects (mild diarrhea) and a longer duration of symptom relief in the herbal formula group compared to the PEG 4000 group.ConclusionAlthough both interventions significantly improved the treatment outcomes, constipation severity, stool consistency and the quality of life were improved more effectively by the herbal formula than by PEG 4000; however, the mechanism of action is not yet understood.Trial registrationThis trial was registered in the Iranian Registry of Clinical Trials (IRCTID: IRCT20200108046056N1). 相似文献
165.
Mesny Emmanuel Barritault Marc Izquierdo Cristina Poncet Delphine d’Hombres Anne Guyotat Jacques Jouanneau Emmanuel Ameli Roxana Honnorat Jérôme Meyronet David Ducray François 《Journal of neuro-oncology》2022,157(3):511-521
Journal of Neuro-Oncology - Molecular glioblastomas (i.e. without the histological but with the molecular characteristics of IDH-wild-type glioblastoma) frequently lack contrast enhancement, which... 相似文献
166.
167.
《European journal of cancer (Oxford, England : 1990)》2014,50(17):3050-3067
Epithelial–mesenchymal transition (EMT) has been reported to play a significant role in tumour metastasis as well as chemoresistance. However, the molecular mechanisms involved in chemotherapy-induced EMT are still unclear. MicroRNA (miRNA) expression and functions have been reported to contribute to phenotypic features of tumour cells. To investigate the roles of miRNAs in chemotherapy-induced EMT, we established two docetaxel-resistant lung adenocarcinoma (LAD) cell models (SPC-A1/DTX and H1299/DTX), which display EMT-like properties and gain increased invasion or migration activity. MiR-451 was found to be significantly downregulated in docetaxel-resistant LAD cells, and re-expression of miR-451 could reverse EMT to mesenchymal–epithelial transition (MET) and inhibit invasion and metastasis of docetaxel-resistant LAD cells both in vitro and in vivo. The proto-oncogene c-Myc was identified as a direct and functional target of miR-451, and further researches confirmed that overexpression of c-Myc which induced extracellular-signal-regulated kinase (ERK)-dependent glycogen synthase kinase-3 beta (GSK-3β) inactivation and subsequent snail activation is essential for acquisition of EMT phenotype induced by loss of miR-451. Furthermore, c-Myc was significantly upregulated in docetaxel-non-responding LAD tissues in comparison with docetaxel-responding tissues, and its expression was inversely correlated with miR-451 expression. This study first reported the involvement of miR-451/c-Myc/ERK/GSK-3β signalling axis in the acquisition of EMT phenotype in docetaxel-resistant LAD cells, suggesting that re-expression of miR-451 or targeting c-Myc will be a potential strategy for the treatment of chemoresistant LAD patients. 相似文献
168.
《European journal of cancer (Oxford, England : 1990)》2014,50(17):2925-2931
BackgroundAromatase inhibitors (AIs) frequently induce or enhance musculoskeletal problems (AI-induced musculoskeletal syndrome (AIMSS)) which sometimes are debilitating. Apart from low oestrogen levels, underlying mechanisms are unknown and likely multiple. We previously hypothesised a role for the growth hormone/insulin like growth factor-I (IGF-I) axis. Here, we report the effect of tamoxifen and AI on IGF-I, IGF binding protein-3 (IGFBP-3) and oestrogen levels from a prospective study.Materials and methodsPostmenopausal women with an early breast cancer scheduled to start adjuvant endocrine therapy with an AI or tamoxifen were recruited. A rheumatologic questionnaire was completed and serum was collected for assessment of IGF-I, IGFBP-3 and oestrogen levels. Re-evaluation was done after 3, 6 and 12 months of therapy.Results84 patients started on tamoxifen (n = 42) or an AI (n = 42). 66% of the latter group experienced worsening of pre-existing or de novo complaints in joint and/or muscle, compared to 29% of tamoxifen-treated patients. AI therapy resulted in elevated IGF-I levels with a statistically significant increase at 6 months (p = 0.0088), whereas tamoxifen users were characterised by a decrease in IGF-I levels at all follow-up times (p < 0.0004). No effect on IGFBP-3 was seen in the latter group. AI-users, however, showed decreased IGFBP-3 levels at 12 months (p = 0.0467). AIMSS was characterised by a decrease in IGFBP-3 levels (p = 0.0007) and a trend towards increased IGF-I/IGFBP-3 ratio (p = 0.0710).ConclusionThese findings provide preliminary evidence that AI-induced musculoskeletal symptoms are associated with changes in the growth hormone (GH)/IGF-I axis. 相似文献
169.
170.
Fabio Manoni Lucia Fornasiero Mauro Ercolin Agostino Tinello Melissa Ferrian Paolo Hoffer Sara Valverde Gianluca Gessoni 《Diagnostic microbiology and infectious disease》2009
Because urinary tract infections (UTIs) are a quite common disease, the gold standard for diagnosing UTIs is still bacterial culture, although a large percentage of samples are negative: unnecessary cultures can be reduced by means of an effective screening test. The analytic performance of a new urine cytometer, the UF-1000i, has been tested on 1463 urine samples submitted to our laboratory for culture. Bacteria and leukocyte counts have been compared by means of the UF-1000i with colony-forming unit (CFU) quantification on citrate lactose electrolytes deficient agar to assess the best cutoff values. By using quantitative cultures and considering as positive a sample with 10 × 105 CFU/mL, 546 positive samples (37%) were observed. If compared with 10 × 105 CFU/mL, the cutoff values obtained were 125 bacteria/μL and 40 leukocytes/ μL, respectively. Analytic parameters such as sensitivity, specificity, positive predictive value, negative predictive value, and correctly classified incidence were satisfactory. Based on the results obtained in this study, when using the UF-1000i analyzer for a screening test for UTI, a cutoff value of 40 white blood cells/μL should be adopted. The cutoff value for bacteria should be 125/μL for those clinical conditions in which 10 × 105 CFU/mL indicates a positivity. 相似文献