全文获取类型
收费全文 | 18618篇 |
免费 | 1221篇 |
国内免费 | 123篇 |
专业分类
耳鼻咽喉 | 191篇 |
儿科学 | 267篇 |
妇产科学 | 252篇 |
基础医学 | 2530篇 |
口腔科学 | 438篇 |
临床医学 | 1700篇 |
内科学 | 3750篇 |
皮肤病学 | 507篇 |
神经病学 | 2101篇 |
特种医学 | 1214篇 |
外科学 | 3525篇 |
综合类 | 109篇 |
一般理论 | 5篇 |
预防医学 | 614篇 |
眼科学 | 208篇 |
药学 | 1207篇 |
中国医学 | 15篇 |
肿瘤学 | 1329篇 |
出版年
2023年 | 154篇 |
2022年 | 163篇 |
2021年 | 503篇 |
2020年 | 346篇 |
2019年 | 448篇 |
2018年 | 517篇 |
2017年 | 423篇 |
2016年 | 515篇 |
2015年 | 644篇 |
2014年 | 776篇 |
2013年 | 876篇 |
2012年 | 1483篇 |
2011年 | 1594篇 |
2010年 | 965篇 |
2009年 | 898篇 |
2008年 | 1327篇 |
2007年 | 1350篇 |
2006年 | 1271篇 |
2005年 | 1193篇 |
2004年 | 1076篇 |
2003年 | 978篇 |
2002年 | 924篇 |
2001年 | 190篇 |
2000年 | 143篇 |
1999年 | 181篇 |
1998年 | 153篇 |
1997年 | 160篇 |
1996年 | 88篇 |
1995年 | 81篇 |
1994年 | 68篇 |
1993年 | 46篇 |
1992年 | 55篇 |
1991年 | 43篇 |
1990年 | 38篇 |
1989年 | 37篇 |
1988年 | 31篇 |
1987年 | 20篇 |
1986年 | 29篇 |
1985年 | 16篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 8篇 |
1970年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 843 毫秒
21.
22.
23.
Tariquidar-induced P-glycoprotein inhibition at the rat blood-brain barrier studied with (R)-11C-verapamil and PET. 总被引:1,自引:0,他引:1
Jens P Bankstahl Claudia Kuntner Aiman Abrahim Rudolf Karch Johann Stanek Thomas Wanek Wolfgang Wadsak Kurt Kletter Markus Müller Wolfgang L?scher Oliver Langer 《Journal of nuclear medicine》2008,49(8):1328-1335
The multidrug efflux transporter P-glycoprotein (P-gp) is expressed in high concentrations at the blood-brain barrier (BBB) and is believed to be implicated in resistance to central nervous system drugs. We used small-animal PET and (R)-11C-verapamil together with tariquidar, a new-generation P-gp modulator, to study the functional activity of P-gp at the BBB of rats. To enable a comparison with human PET data, we performed kinetic modeling to estimate the rate constants of radiotracer transport across the rat BBB. METHODS: A group of 7 Wistar Unilever rats underwent paired (R)-11C-verapamil PET scans at an interval of 3 h: 1 baseline scan and 1 scan after intravenous injection of tariquidar (15 mg/kg, n = 5) or vehicle (n = 2). RESULTS: After tariquidar administration, the distribution volume (DV) of (R)-11C-verapamil was 12-fold higher than baseline (3.68 +/- 0.81 vs. 0.30 +/- 0.08; P = 0.0007, paired t test), whereas the DVs were essentially the same when only vehicle was administered. The increase in DV could be attributed mainly to an increased influx rate constant (K1) of (R)-11C-verapamil into the brain, which was about 8-fold higher after tariquidar. A dose-response assessment with tariquidar provided an estimated half-maximum effect dose of 8.4 +/- 9.5 mg/kg. CONCLUSION: Our data demonstrate that (R)-11C-verapamil PET combined with tariquidar administration is a promising approach to measure P-gp function at the BBB. 相似文献
24.
25.
Claudia M. Dillier Daniel Trachsel Werner Baulig Claudine Gysin Andreas C. Gerber Markus Weiss 《Journal canadien d'anesthésie》2004,51(1):72-75
PURPOSE: To present a case of laryngeal damage in an infant caused by a too large and inappropriately designed cuffed tracheal tube. CLINICAL FEATURES: A 13-month-old child undergoing cardiac surgery was intubated with an uncuffed endotracheal tube with an internal diameter (ID) of 4.0 mm. Because of an important air leak around the tracheal tube during mechanical ventilation, a cuffed endotracheal tube ID 4.0 mm was inserted. The air leak with the tube cuff not inflated was acceptable at 25 cm H2O airway pressure. After extubation on the third postoperative day, the patient showed increasing stridor and respiratory deterioration. Fibreoptic laryngoscopy of the spontaneously breathing patient showed a large intra-laryngeal web. After surgical removal of the web, the child rapidly recovered and was discharged from the hospital on the 12th postoperative day. Inspection of the 4.0 mm (ID) cuffed tracheal tube revealed a cuff positioned inappropriately high and an increase of 0.7 mm in outer tube diameter compared to the 4.0 mm (ID) uncuffed tracheal tube from the same manufacturer. The tube cuff is likely to be situated within the larynx when placed in accordance to insertion depth formulas or radiological criteria, as used for uncuffed tracheal tubes in children. CONCLUSION: The larger than expected tracheal tube with its intra-laryngeal cuff position in a 13-month-old child likely caused mucosal damage and an inflammatory reaction within the larynx resulting in granulation tissue formation and fibrous healing around the tracheal tube. 相似文献
26.
Andreas Blana Stefan Denzinger Markus Lenhart Wolf F Wieland Roman Ganzer 《International journal of urology》2007,14(5):450-451
We report a case of recurrent inguinal lymphocele formation after inguinal lymphadenectomy treated by lymphographic mapping and selective ligation of the lymphatic vessels. Lymphographic mapping was performed by puncturing a lymphatic vessel at the dorsum of the foot. After isolating the vessels that drained into the lymphocele, they were clipped and divided through a small skin incision. The described technique showed an instant and complete suspension of the lymph secretion with subsequent complete healing. Lymphatic mapping and selective ligation of afferent lymphatic vessels proved to be an effective treatment of a recurrent inguinal lymphocele. 相似文献
27.
Radiofrequency-ablation of unresectable primary and secondary liver tumors: results in 88 patients 总被引:5,自引:0,他引:5
Philipp Hildebrand Markus Kleemann Uwe J. Roblick Lutz Mirow Matthias Birth Thorsten Leibecke Hans-Peter Bruch 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2006,391(2):118-123
Background and aims Radiofrequency-ablation (RFA) is increasingly used for destruction of unresectable primary and secondary liver tumors. We
report our experience in the use of RFA for the management of unresectable hepatic malignancies.
Patients and methods Between February 2000 and December 2004 we have undertaken 120 RFA procedures to ablate 426 unresectable primary or metastatic
liver tumors in 88 patients. RFA was performed via laparotomy (n=68), laparoscopy (n=9) or a percutaneous approach (n=43). Primary liver cancer was treated in seven patients (8%) and metastatic liver tumors were treated in 81 patients (92%).
All patients were followed to assess complications, treatment response and recurrence of malignant disease.
Results Procedure-related complication rate was low (3.4%). During a mean follow-up of 21.2 months, 15 patients had local tumor progression
(17%), 21 patients (23,9%) had new malignant disease and 27 patients (30.7%) died from intervention-unrelated complications
of their malignant disease. Additional liver lesions were identified in 27 (35%) of 77 cases by intraoperative ultrasound.
Thirty-six patients received simultaneous resection and RFA.
Conclusion RFA is a safe, well-tolerated and effective treatment for patients with unresectable primary and secondary liver malignancies. 相似文献
28.
Stephen Sawada Otto Muzik Rob S. B. Beanlands Edwin Wolfe Gary D. Hutchins Markus Schwaiger 《Journal of nuclear cardiology》1995,2(5):413-422
Background
Experimental studies have shown that positron emission tomography (PET) with 13N-labeled ammonia provides accurate quantification of regional myocardial blood flow (MBF) under rest and stress conditions. To establish the clinical utility of this method, the interobserver variability and the temporal variability of serial measurements of blood flow and coronary flow reserve (CFR) must be known. This study investigated the interobserver and temporal reproducibility of 13N-labeled PET for measurement of MBF and CFR. 相似文献29.
H. S. Markus A. M. Tomkins G. M. Stern 《Journal of neural transmission (Vienna, Austria : 1996)》1993,5(2):117-125
Summary An anthropometric study was performed in 95 subjects (53 male, 42 female) with Parkinson's disease. Weight, height, triceps and biceps skin-fold thicknesses, and mid-arm circumference were recorded. A high incidence of undernutrition was found (23.6% of males and 22.5% of females, as defined by recent British guidelines). A subgroup of severely disabled patients with Parkinson's disease had a significantly lower mean body mass index than a similarly disabled control group with chronic pyramidal upper motor neuron lesions (males 20.6v 23.2 kg/m2 p<0.05; females 20.6v 26.6 kg/m2 p<0.01), suggesting that the undernutrition is not due to chronic illness or immobility alone. Correlation between anthropometric indices and clinical features of disease demonstrated that the presence of moderate or severe dyskinetic movements was the clinical parameter most strongly related to undernutrition. The reduction in anthropometric indices was most marked for skin fold thickness (related to percentage body fat) and least for arm muscle circumference (related to lean body mass); therefore the weight loss seen in Parkinson's disease is primarily due to fat loss rather than muscle loss. 相似文献
30.
Biodistribution and pharmacokinetics of the alphavbeta3-selective tracer 18F-galacto-RGD in cancer patients. 总被引:5,自引:0,他引:5
Ambros J Beer Roland Haubner Michael Goebel Stephan Luderschmidt Mary E Spilker Hans-Jürgen Wester Wolfgang A Weber Markus Schwaiger 《Journal of nuclear medicine》2005,46(8):1333-1341
(18)F-Galacto-RGD has been developed for PET of alpha(v)beta(3) integrin expression, a receptor involved in, for example, angiogenesis and metastasis. Our aim was to study the kinetics and biodistribution of (18)F-Galacto-RGD in cancer patients. METHODS: Nineteen patients with metastases of malignant melanoma (n = 7), sarcomas (n = 10), or osseous metastases (n = 2) were examined. After injection of 133-200 MBq (18)F-Galacto-RGD, 3 consecutive emission scans from the pelvis to the thorax or dynamic emission scans of the tumor over 60 min, followed by 1 static emission scan of the body, were acquired. Time-activity curves and standardized uptake values (SUVs) were derived by image region-of-interest analysis with image-based arterial input functions. Compartmental modeling was used to derive the distribution volume for muscle tissue and tumors. RESULTS: (18)F-Galacto-RGD showed rapid blood clearance and primarily renal excretion. SUVs in tumors ranged from 1.2 to 9.0. Tumor-to-blood and tumor-to-muscle ratios increased over time, with peak ratios of 3.1 +/- 2.0 and 7.7 +/- 4.3, respectively, at 72 min. The tumor kinetics were consistent with a 2-tissue compartment model with reversible specific binding. Distribution volume values were, on average, 4 times higher for tumor tissue (1.5 +/- 0.8) than those for muscle tissue (0.4 +/- 0.1). The data suggest that there was only minimal free and bound (specific or nonspecific) tracer in muscle tissue. CONCLUSION: (18)F-Galacto-RGD demonstrates a highly favorable biodistribution in humans with specific receptor binding. Most important, this study shows that (18)F-Galacto-RGD allows visualization of alpha(v)beta(3) expression in tumors with high contrast. Consequently, this tracer offers a new strategy for noninvasive monitoring of molecular processes and may supply helpful information for planning and controlling of therapeutic approaches targeting the alpha(v)beta(3) integrin. 相似文献