全文获取类型
收费全文 | 4809篇 |
免费 | 238篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 53篇 |
妇产科学 | 65篇 |
基础医学 | 516篇 |
口腔科学 | 84篇 |
临床医学 | 589篇 |
内科学 | 1457篇 |
皮肤病学 | 53篇 |
神经病学 | 577篇 |
特种医学 | 90篇 |
外科学 | 421篇 |
综合类 | 13篇 |
预防医学 | 460篇 |
眼科学 | 33篇 |
药学 | 358篇 |
中国医学 | 3篇 |
肿瘤学 | 279篇 |
出版年
2024年 | 5篇 |
2023年 | 25篇 |
2022年 | 85篇 |
2021年 | 179篇 |
2020年 | 92篇 |
2019年 | 157篇 |
2018年 | 198篇 |
2017年 | 117篇 |
2016年 | 118篇 |
2015年 | 126篇 |
2014年 | 217篇 |
2013年 | 261篇 |
2012年 | 413篇 |
2011年 | 429篇 |
2010年 | 262篇 |
2009年 | 211篇 |
2008年 | 322篇 |
2007年 | 301篇 |
2006年 | 311篇 |
2005年 | 284篇 |
2004年 | 258篇 |
2003年 | 225篇 |
2002年 | 201篇 |
2001年 | 24篇 |
2000年 | 15篇 |
1999年 | 28篇 |
1998年 | 38篇 |
1997年 | 32篇 |
1996年 | 22篇 |
1995年 | 27篇 |
1994年 | 18篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
1962年 | 2篇 |
1961年 | 1篇 |
1960年 | 3篇 |
1933年 | 1篇 |
1929年 | 1篇 |
排序方式: 共有5065条查询结果,搜索用时 15 毫秒
91.
Puche JE García-Fernández M Muntané J Rioja J González-Barón S Castilla Cortazar I 《Endocrinology》2008,149(5):2620-2627
Serum IGF-I levels decline with age. We have recently reported that in aging rats the exogenous administration of IGF-I restores IGF-I circulating levels and age related-changes, improving glucose and lipid metabolisms, increasing testosterone levels and serum total antioxidant capability, and reducing oxidative damage in the brain and liver associated with a normalization of antioxidant enzyme activities. Understanding that mitochondria are one of the most important cellular targets of IGF-I, the aims of this study were to characterize mitochondrial dysfunction and study the effect of IGF-I therapy on mitochondria, leading to cellular protection in the following experimental groups: young controls, untreated old rats, and aging rats treated with IGF-I. Compared with young controls, untreated aging rats showed an increase of oxidative damage in isolated mitochondria with a mitochondrial dysfunction characterized by: depletion of membrane potential with increased proton leak rates and intramitochondrial free radical production, and a significant reduction of ATPase and complex IV activities. In addition, mitochondrial respiration from untreated aging rats was atractyloside insensitive, suggesting that the adenine nucleotide translocator was uncoupled. The adenine nucleotide translocator has been shown to be one of the most sensitive locations for pore opening. Accordingly, untreated aging rats showed a significant overexpression of the active fragment of caspases 3 and 9. IGF-I therapy corrected these parameters of mitochondrial dysfunction and reduced caspase activation. In conclusion, these results show that the cytoprotective effect of IGF-I is closely related to a mitochondrial protection, leading to reduce free radical production, oxidative damage, and apoptosis, and to increased ATP production. 相似文献
92.
Luis M. Jara Pilar Cortés Germán Bou Jordi Barbé Jesús Aranda 《Antimicrobial agents and chemotherapy》2015,59(7):4318-4320
The effect of antimicrobials on SOS-mediated mutagenesis induction depends on the bacterial species and the antimicrobial group. In this work, we studied the effect of different families of antimicrobial agents used in clinical therapy against Acinetobacter baumannii in the induction of mutagenesis in this multiresistant Gram-negative pathogen. The data showed that ciprofloxacin and tetracycline induce SOS-mediated mutagenesis, whereas colistin and meropenem, which are extensively used in clinical therapy, do not. 相似文献
93.
94.
Mattia Quattrocelli Melissa Swinnen Giorgia Giacomazzi Jordi Camps Ines Barthélemy Gabriele Ceccarelli Ellen Caluwé Hanne Grosemans Lieven Thorrez Gloria Pelizzo Manja Muijtjens Catherine M. Verfaillie Stephane Blot Stefan Janssens Maurilio Sampaolesi 《The Journal of clinical investigation》2015,125(12):4463-4482
Conditions such as muscular dystrophies (MDs) that affect both cardiac and skeletal muscles would benefit from therapeutic strategies that enable regeneration of both of these striated muscle types. Protocols have been developed to promote induced pluripotent stem cells (iPSCs) to differentiate toward cardiac or skeletal muscle; however, there are currently no strategies to simultaneously target both muscle types. Tissues exhibit specific epigenetic alterations; therefore, source-related lineage biases have the potential to improve iPSC-driven multilineage differentiation. Here, we determined that differential myogenic propensity influences the commitment of isogenic iPSCs and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages. Differential myogenic propensity did not influence pluripotency, but did selectively enhance chimerism of MiP-derived tissue in both fetal and adult skeletal muscle. When injected into dystrophic mice, MiPs engrafted and repaired both skeletal and cardiac muscle, reducing functional defects. Similarly, engraftment into dystrophic mice of canine MiPs from dystrophic dogs that had undergone TALEN-mediated correction of the MD-associated mutation also resulted in functional striatal muscle regeneration. Moreover, human MiPs exhibited the same capacity for the dual differentiation observed in murine and canine MiPs. The findings of this study suggest that MiPs should be further explored for combined therapy of cardiac and skeletal muscles. 相似文献
95.
Eduard Tornero Sebastian García-Ramiro Juan C. Martínez-Pastor Guillem Bori Jordi Bosch Laura Morata Marta Sala Misericordia Basora Josep Mensa Alex Soriano 《Antimicrobial agents and chemotherapy》2015,59(2):831-837
The aim of this study was to compare the prosthetic joint infection (PJI) rate after total joint arthroplasty in two consecutive periods of treatment with different antibiotic prophylaxes: cefuroxime versus cefuroxime plus teicoplanin. We retrospectively reviewed 1,896 patients who underwent total hip arthroplasty or total knee arthroplasty between March 2010 and February 2013. From March 2010 to August 2011, patients received 1.5 g of cefuroxime during induction of anesthesia and another 1.5 g 2 h later (the C group). From September 2011, 800 mg of teicoplanin was added to cefuroxime (the CT group). Throughout the period studied, there were no variations in pre- or postoperative protocols. Univariate and multivariate analyses were performed to evaluate independent predictors of PJI. There were 995 (55.7%) patients in the C group and 791 (44.3%) in the CT group. Patients in the CT group had a significantly lower PJI rate than patients in the C group (1.26% versus 3.51%, P = 0.002). There were no infections due to Staphylococcus aureus in the CT group (0% versus 1.6% in the C group, P < 0.001). A stepwise forward Cox regression model identified male sex (hazard ratio [HR], 3.85; 95% confidence interval [CI], 2.09 to 7.18), a body mass index of ≥35 kg/m2 (HR, 2.93; 95% CI, 1.37 to 6.27), the presence of lung disease (HR, 2.46; 95% CI, 1.17 to 5.15), and red blood cell transfusion (HR, 3.70; 95% CI, 1.89 to 7.23) to be independent variables associated with a higher risk of PJI. The addition of teicoplanin was associated with a lower risk of infection (HR, 0.35; 95% CI, 0.17 to 0.74). In conclusion, the addition of teicoplanin to cefuroxime during primary arthroplasty was associated with a significant reduction in the global PJI rate due to a reduction of infections caused by Gram-positive bacteria. 相似文献
96.
Casademont J Rodriguez-Santiago B Miró O Beato A López S Nunes V Cardellach F 《Aging clinical and experimental research》2005,17(1):1-7
BACKGROUND AND AIMS: The potential influence of impaired oxidative metabolism in the modulation of manifestations in sporadic Alzheimer's disease (AD) has attracted much attention in the last 50 years. Unfortunately, many clinical and experimental results aiming at proving this hypothesis are still controversial. The aim was to study the enzymatic activities of respiratory chain (RC) complexes I through V in three brain areas of a group of patients with definite AD, and to compare the results with a group of normal brains. We simultaneously assessed the lipid peroxidation of the samples as a measure of free radical damage. METHODS: The specific activity of the individual complexes of the RC was measured spectrophotometrically, and the loss of cis-parinaric acid fluorescence was used to determine the chemical process of lipid peroxidation. RESULTS: We were not able to detect differences in any of the analyzed RC enzymatic activities, or in the level of lipid peroxidation between patients with AD and controls. Instead, differences were found in the number of mitochondria and in the intrinsic enzymatic activities of complexes III and IV in various brain areas. CONCLUSIONS: Spectrophotometric enzymatic analyses of respiratory complexes in brain homogenates do not support the primary contribution of mitochondrial RC dysfunction in the pathogenesis of AD. 相似文献
97.
High-Titer Retroviral Vectors Containing the Enhanced Green Fluorescent Protein Gene for Efficient Expression in Hematopoietic Cells 总被引:11,自引:1,他引:11
98.
Paula Espinal Noraida Mosqueda Murat Telli Tanny van der Reijden Dora Rolo Dietmar Fernández-Orth Lenie Dijkshoorn Ignasi Roca Jordi Vila 《Antimicrobial agents and chemotherapy》2015,59(10):6657-6660
In this study, we describe the molecular characterization of a plasmid-located blaNDM-1 harbored by an Acinetobacter clinical isolate recovered from a patient in Turkey that putatively constitutes a novel Acinetobacter species, as shown by its distinct ARDRA (amplified 16S ribosomal DNA restriction analysis) profile and molecular sequencing techniques. blaNDM-1 was carried by a conjugative plasmid widespread among non-baumannii Acinetobacter isolates, suggesting its potential for dissemination before reaching more clinically relevant Acinetobacter species. 相似文献
99.
100.
Jordi Calabia MD Pere Torguet MD Isabel Garcia MD Nadia Martin MD Gerard Mate MD Adriana Marin MD Carolina Molina MD Marti Valles MD PhD 《Journal of clinical hypertension (Greenwich, Conn.)》2014,16(3):186-191
The renal resistive index (RRI) measured by Doppler sonography is a marker of microvascular status that can be generalized to the whole of the arterial tree. Its association with large‐vessel dysfunction, such as arterial stiffness or the atherosclerotic burden, can help to establish physiopathological associations between macrocirculation and microcirculation. The authors conducted a cross‐sectional study of hypertensive patients (n=202) and a healthy control group (n=16). Stiffness parameters, atherosclerotic burden, and determination of the RRI in both kidneys were performed. The average RRI was 0.69±0.08 and was significantly greater in patients with diabetes and chronic kidney disease. Renal resistive index positively correlated with age, creatinine, and albuminuria. Positive correlations were found with arterial stiffness parameters (pulse wave velocity, ambulatory arterial stiffness index, and 24‐hour pulse pressure), as well as atherosclerotic burden and endothelial dysfunction measured as asymmetric dimethylarginine in serum. In the multivariate analysis, independent factors for increased RRI were age, renal function, 24‐hour diastolic blood pressure, and arterial stiffness. The authors concluded that there is an independent association between renal hemodynamics and arterial stiffness. This, together with the atherosclerotic burden and endothelial dysfunction, suggests that there is a physiopathologic relationship between macrovascular and microvascular impairment. 相似文献