全文获取类型
收费全文 | 8814篇 |
免费 | 431篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 271篇 |
儿科学 | 294篇 |
妇产科学 | 386篇 |
基础医学 | 1463篇 |
口腔科学 | 77篇 |
临床医学 | 560篇 |
内科学 | 1917篇 |
皮肤病学 | 190篇 |
神经病学 | 863篇 |
特种医学 | 134篇 |
外科学 | 681篇 |
综合类 | 57篇 |
一般理论 | 1篇 |
预防医学 | 658篇 |
眼科学 | 229篇 |
药学 | 1014篇 |
中国医学 | 16篇 |
肿瘤学 | 468篇 |
出版年
2023年 | 64篇 |
2022年 | 282篇 |
2021年 | 404篇 |
2020年 | 165篇 |
2019年 | 237篇 |
2018年 | 277篇 |
2017年 | 245篇 |
2016年 | 253篇 |
2015年 | 279篇 |
2014年 | 354篇 |
2013年 | 490篇 |
2012年 | 714篇 |
2011年 | 763篇 |
2010年 | 347篇 |
2009年 | 255篇 |
2008年 | 463篇 |
2007年 | 485篇 |
2006年 | 541篇 |
2005年 | 442篇 |
2004年 | 470篇 |
2003年 | 400篇 |
2002年 | 375篇 |
2001年 | 142篇 |
2000年 | 142篇 |
1999年 | 104篇 |
1998年 | 41篇 |
1997年 | 24篇 |
1996年 | 30篇 |
1995年 | 19篇 |
1994年 | 20篇 |
1992年 | 20篇 |
1991年 | 15篇 |
1990年 | 18篇 |
1988年 | 23篇 |
1987年 | 17篇 |
1985年 | 22篇 |
1984年 | 14篇 |
1983年 | 14篇 |
1982年 | 16篇 |
1981年 | 18篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 17篇 |
1976年 | 13篇 |
1975年 | 31篇 |
1974年 | 23篇 |
1973年 | 22篇 |
1972年 | 12篇 |
1971年 | 15篇 |
排序方式: 共有9279条查询结果,搜索用时 15 毫秒
1.
2.
3.
Melatonin reduces oxidative stress and improves vascular function in pulmonary hypertensive newborn sheep 下载免费PDF全文
Flavio Torres Alejandro González‐Candia Camilo Montt Germán Ebensperger Magdalena Chubretovic María Serón‐Ferré Roberto V. Reyes Aníbal J. Llanos Emilio A. Herrera 《Journal of pineal research》2015,58(3):362-373
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN. 相似文献
4.
Agata Cieślik-Bielecka Paweł Reichert Rafał Skowroński Tomasz Bielecki 《Platelets》2019,30(6):728-736
The current literature suggests that the antibacterial effect of leukocyte- and platelet-rich plasma (L-PRP) is directly related to platelet and leukocyte concentrations. The aim of this study was twofold: first, to evaluate the antimicrobial effect of L-PRP against selected bacterial strains in vitro, and second, to correlate this effect with leukocyte and platelet content in the final concentration. Blood was collected from 20 healthy males, and L-PRP, acellular plasma (AP), and autologous thrombin were consecutively prepared. Flow cytometry analysis of the blood, L-PRP, and AP was performed. The L-PRP gel, liquid L-PRP, and thrombin samples were tested in vitro for their antibacterial properties against seven selected bacterial strains using the Kirby–Bauer disk-diffusion method. There was notable antimicrobial activity against selected bacterial strains. No statistically significant correlations between antimicrobial activities and the platelet concentration in L-PRP were observed. Statistically significant positive correlations between selected leukocyte subtypes and antimicrobial activity were noted. A negative correlation was found between elevated monocyte count and antimicrobial activity of L-PRP against one bacterial strain studied. L-PRP possesses antimicrobial activity and can be potentially useful in the fight against certain postoperative infections. The bactericidal effect of L-PRP is caused by leukocytes, and there exists a relationship among selected leukocyte subtypes and L-PRP antimicrobial activity. 相似文献
5.
Inflammation but not obesity or insulin resistance is associated with increased plasma fibroblast growth factor 23 concentration in the elderly 下载免费PDF全文
6.
7.
Magdalena Cortes Alessandro Lambiase Marta Sacchetti Silvia Aronni Stefano Bonini 陈旭 《美国医学会眼科杂志(中文版)》2006,18(1):30-32
泪管-耳-牙-指(趾)(LADD)综合征是一种具有多种表现的常染色体显性遗传疾病。最初在1967年由Levy报道。1例双侧泪液系统缺失、杯状耳、干嘴,以及牙、手臂和指(趾)异常的单发病例。之后一些新发现的临床表现,如肾脏异常、唾液腺缺乏、先天性髋脱位、先天性裂孔疝和横膈疝、感觉性耳聋和传导性耳聋、牙发育不全、四肢异常、口腔干燥和眼干都被报道与此综合征有关。 相似文献
8.
9.
Daniel P Potaczek Anetta Undas Magdalena Celinska-Lowenhoff Andrew Szczeklik 《Blood coagulation & fibrinolysis》2006,17(1):35-38
To evaluate whether the interleukin-6 (IL-6) -174 G/C polymorphism might alter the effects of micronized fenofibrate or simvastatin therapy on inflammatory markers, we measured IL-6, C-reactive protein, CD40 ligand, adhesion molecules, P-selectin and monocyte chemoattractant protein-1 in hypercholesterolemic patients both before and after a 30-day treatment. Serum IL-6 levels were significantly higher in patients with the GC or CC genotypes (P=0.04). The presence of the C allele was associated with greater absolute reduction of IL-6 levels (P=0.04) following fenofibrate treatment. There was no significant association between the -174 G/C IL-6 polymorphism and the effects of simvastatin treatment. A relationship between the -174 G/C IL-6 polymorphism and the anti-inflammatory action of fenofibrate reported might be useful in the optimization of the treatment regimen in patients receiving this class of drugs. 相似文献
10.
Kamil Torres Anna Torres Grzegorz J. Staśkiewicz Andrzej Chrościcki Tadeusz Łoś Ryszard Maciejewski 《Surgical endoscopy》2009,23(9):2117-2123
Background Surgical procedures enhance production of pro- and anti-inflammatory cytokines and angiogenic factors that play a pivotal
role in the immunological response to surgical trauma and take part in the pathogenesis of tumor growth and adhesions formation.
The purpose of the study was to access the influence of low-pressure CO2 pneumoperitoneum on the inflammatory and angiogenic responses during the postoperative period after laparoscopy.
Methods The study group consisted of 40 patients, operated on due to cholelithiasis using standard-pressure (n = 20) and low-pressure (n = 20) CO2 pneumoperitoneum. Serum concentration of interleukin (IL)-6, IL-8, IL-10, vascular endothelial growth factor (VEGF)-A, and
endostatin were measured before and at 6, 24, and 48 h after surgery with commercially available enzyme-linked immunosorbent
assay (ELISA).
Results Concentrations of IL-6 increased significantly after the operations in both groups. No differences were observed between the
groups in regards to IL-6, IL-8, and IL-10 levels. Concentrations of VEGF-A measured at 6 and 48 h were significantly lower
in patients who underwent laparoscopies performed with low-pressure pneumoperitoneum. No significant variations were observed
in endostatin serum concentration. Concentrations of the studied parameters were not influenced by duration of surgery or
by age, gender, or body mass index (BMI) of the patients.
Conclusions The results obtained in our study do not show any significant differences between studied operative procedures with regards
to systemic inflammatory response. Changes in the concentrations of VEGF-A and endostatin observed in the studied population
may suggest this technique is more favorable with regards to angiogenesis process intensity, along with all its consequences
and implications. 相似文献