全文获取类型
收费全文 | 3988篇 |
免费 | 270篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 54篇 |
儿科学 | 289篇 |
妇产科学 | 405篇 |
基础医学 | 397篇 |
口腔科学 | 117篇 |
临床医学 | 323篇 |
内科学 | 887篇 |
皮肤病学 | 82篇 |
神经病学 | 267篇 |
特种医学 | 115篇 |
外科学 | 581篇 |
综合类 | 85篇 |
一般理论 | 1篇 |
预防医学 | 190篇 |
眼科学 | 109篇 |
药学 | 209篇 |
中国医学 | 11篇 |
肿瘤学 | 154篇 |
出版年
2023年 | 32篇 |
2022年 | 50篇 |
2021年 | 79篇 |
2020年 | 70篇 |
2019年 | 75篇 |
2018年 | 113篇 |
2017年 | 95篇 |
2016年 | 127篇 |
2015年 | 133篇 |
2014年 | 135篇 |
2013年 | 235篇 |
2012年 | 280篇 |
2011年 | 319篇 |
2010年 | 176篇 |
2009年 | 145篇 |
2008年 | 282篇 |
2007年 | 301篇 |
2006年 | 256篇 |
2005年 | 278篇 |
2004年 | 231篇 |
2003年 | 193篇 |
2002年 | 163篇 |
2001年 | 67篇 |
2000年 | 51篇 |
1999年 | 50篇 |
1998年 | 17篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 16篇 |
1992年 | 18篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1982年 | 8篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1973年 | 8篇 |
1971年 | 10篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1968年 | 9篇 |
排序方式: 共有4276条查询结果,搜索用时 140 毫秒
61.
62.
Pupose
Obstructive sleep apnea (OSA) is associated with various metabolic disorders, and oxidative stress was suggested to play an important role. In the present study, we aimed to investigate serum adiponectin and oxidative stress markers, especially protein carbonyls, and to evaluate the correlation between these parameters and lipid, insulin and fasting glucose concentrations in OSA patients and controls. 相似文献63.
Targeted vessel reconstruction in non‐contrast‐enhanced steady‐state free precession angiography
下载免费PDF全文
![点击此处可从《NMR in biomedicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Efe Ilicak Suheyla Cetin Elif Bulut Kader Karli Oguz Emine Ulku Saritas Gozde Unal Tolga Çukur 《NMR in biomedicine》2016,29(5):532-544
Image quality in non‐contrast‐enhanced (NCE) angiograms is often limited by scan time constraints. An effective solution is to undersample angiographic acquisitions and to recover vessel images with penalized reconstructions. However, conventional methods leverage penalty terms with uniform spatial weighting, which typically yield insufficient suppression of aliasing interference and suboptimal blood/background contrast. Here we propose a two‐stage strategy where a tractographic segmentation is employed to auto‐extract vasculature maps from undersampled data. These maps are then used to incur spatially adaptive sparsity penalties on vascular and background regions. In vivo steady‐state free precession angiograms were acquired in the hand, lower leg and foot. Compared with regular non‐adaptive compressed sensing (CS) reconstructions (CSlow), the proposed strategy improves blood/background contrast by 71.3 ± 28.9% in the hand (mean ± s.d. across acceleration factors 1–8), 30.6 ± 11.3% in the lower leg and 28.1 ± 7.0% in the foot (signed‐rank test, P < 0.05 at each acceleration). The proposed targeted reconstruction can relax trade‐offs between image contrast, resolution and scan efficiency without compromising vessel depiction. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
64.
65.
66.
Xanthelasmas of the upper gastrointestinal tract 总被引:1,自引:0,他引:1
Gencosmanoglu R Sen-Oran E Kurtkaya-Yapicier O Tozun N 《Journal of gastroenterology》2004,39(3):215-219
Background Gastric xanthelasma is a benign and uncommon lesion with a variably reported frequency, while esophageal and duodenal xanthelasmas are quite rare.Methods Seventeen patients who had the diagnosis of xanthelasma in the upper gastrointestinal tract were analyzed retrospectively with respect to their demographic, clinical, endoscopic, and histopathologic features. All lesions suspected as xanthelasma were totally removed by either hot biopsy forceps or a snare with the technique of endoscopic mucosal resection.Results The incidence of upper gastrointestinal xanthelasmas in 7320 patients who had upper gastro-intestinal endoscopy was 0.23%. There were 9 (53%) men and 8 (47%) women, with a median age of 50 years (range, 24–80 years). The most common location of xanthelasmas was the stomach (76%), followed by the esophagus (12%) and duodenum (12%). All lesions were observed as yellow-white colored plaques at endoscopy. Multiple xanthelasmas were detected in 4 patients (24%); in the duodenum in 2, esophagus in 1, and stomach in 1. One patient had xanthelasma within a gastric hyperplastic polyp. The size of the lesion was less than 5mm in diameter in 14 (82%) patients and between 5 and 10mm in diameter in 3 (18%). Thirteen (76%) patients had moderate to severe atrophic gastritis, while the remainder had normal gastric mucosa.Conclusions Xanthelasmas of the upper gastrointestinal tract were mostly located in the stomach in the present series, which includes the second and third reported cases of duodenal xanthelasma, the second case of xanthelasma developed within a hyperplastic gastric polyp, and the fourth and the fifth cases of esophageal xanthelasma. 相似文献
67.
Ceyhan M Yildirim I Tekeli A Yurdakok M Us E Altun B Kutluk T Cengiz AB Gurbuz V Barin C Bagdat A Cetinkaya D Gur D Tuncel O 《American journal of infection control》2008,36(6):453-457
Three clusters of Chryseobacterium meningosepticum infections in a tertiary health center in July 2006 and January 2007 involving 8 newborns and 5 older children were investigated. The index patient was from the neonatal intensive care unit, and the older patients were from other pediatric wards. Cultures were obtained from the environment and from health care workers' hands as part of an outbreak investigation. C meningosepticum was isolated from hand cultures obtained from a senior resident and from environmental cultures obtained from powdered infant formula, an electrical button, a computer keyboard, phone, a doorknob, and an Ambu bag. Antibiogram typing and enterobacterial repetitive intergenic consensus sequence polymerase chain reaction indicated that all of the isolates were epidemiologically related. Nine patients improved on antimicrobial treatment, and 4 premature infants died after the infection. C meningosepticum is a well-known etiologic agent for nosocomial infections involving newborns and immunocompromised patients. Wet and dry environmental surfaces and equipment may act as a source or play a role in disseminating the microorganism. Outbreaks may be controlled with strong emphasis on infection control measures. 相似文献
68.
Increased immunoglobulin E response in acute coronary syndromes 总被引:3,自引:0,他引:3
The role of inflammation and mast cell activation has been implicated in atherosclerotic plaque destabilization and rupture. To investigate the role of immunoglobulin E (IgE) in acute coronary syndrome, a prospective clinical study was conducted in patients with acute myocardial infarction (AMI), unstable angina pectoris (UAP), stable angina pectoris (SAP), and healthy controls. IgE levels were serially measured and compared in consecutive patients with AMI (n = 16) and UAP (n = 14) on days 1, 3, 7, 21 after admission and 3 months later and only once in stable angina pectoris (n = 15) and healthy controls (n = 14). In addition, blood eosinophil and basophil levels on admission were measured in all groups and compared. Initial IgE levels determined at admission in patients with AMI, UAP, and SAP were significantly higher than levels in the control group (p = 0.002). Initial high IgE level in AMI on day 1 increased to a peak by day 7 (p = 0.024), then gradually decreased by day 21 and at 3 months (p = 0.052). High IgE level in UAP persisted by day 7 and gradually decreased by day 21 and 3 months (p = 0.037 and p = 0.018, respectively). Blood eosinophil count on admission was significantly higher in UAP than in the control group (p = 0.005). Basophil levels of both AMI and UAP groups on admission were found to be elevated as opposed to control group (p = 0.02 and p = 0.012, respectively). This study demonstrates that the level of IgE significantly increased during the acute phase of acute coronary syndromes and gradually decreased, supporting the role of acute inflammatory response and mast cell involvement in plaque rupture. 相似文献
69.
Abaci A Oguzhan A Unal S Kiranatli B Eryol NK Basar E Ergin A Cetin S 《Cardiology》2002,98(1-2):50-59
OBJECTIVES: The vena contracta is the narrowest region of the regurgitant or stenotic jet just downstream the orifice and reflects the size of that orifice. This study was performed to assess the accuracy of the vena contracta width (VCW) in evaluating the severity of mitral stenosis (MS) and to compare the mitral valve area (MVA) determined by VCW with MVAs obtained by other more traditional echocardiographic methods. METHODS: We studied 59 patients (43 females, 42 +/- 14 years) with MS. VCW was measured in the apical four chamber view by Doppler color flow mapping. The largest diameter of the VCW during diastole was measured for at least three cardiac cycles and averaged. MVA was calculated from the following equation: pir(2), where r = VCW/2. MVA was also determined by planimetry, the pressure half-time method, and by the Gorlin formula. RESULTS: In this study, the width of the vena contracta ranged from 0.89 to 1.73 cm (mean 1.30 +/- 0.21). MVA, calculated based on the VCW, ranged from 0.63 to 2.35 cm(2) (mean 1.36 +/- 0.41). MVA by VCW (1.36 +/- 0.41 cm(2)) showed good correlations with three comparative techniques: (1) the cross-sectional area by planimetry (1.35 +/- 0.36 cm(2), mean difference = 0.21 +/- 0.16 cm(2), y = 0.91x + 0.14, r = 0.79, SEE = 0.26 cm(2), p < 0.001); (2) the area derived from the Doppler pressure half-time (1.27 +/- 0.32 cm(2), mean difference = 0.22 +/- 0.19 cm(2), y = 0.97x + 0.13, r = 0.76, SEE = 0.27 cm(2), p < 0.001), and (3) the area derived from the Gorlin equation in the 18 patients who underwent catheterization (1.27 +/- 0.35 cm(2), mean difference = 0.19 +/- 0.16, y = 0.98x + 0.05, r = 0.81, SEE = 0.26 cm(2), p < 0.001). CONCLUSIONS: These findings suggest that Doppler color flow imaging of the MS jet in the vena contracta can provide an accurate estimation of MVA and appears to be potentially applicable in the assessment of the severity of MS. 相似文献