全文获取类型
收费全文 | 71341篇 |
免费 | 44068篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 1475篇 |
儿科学 | 4179篇 |
妇产科学 | 505篇 |
基础医学 | 15187篇 |
口腔科学 | 5028篇 |
临床医学 | 12092篇 |
内科学 | 22402篇 |
皮肤病学 | 7428篇 |
神经病学 | 13044篇 |
特种医学 | 2116篇 |
外科学 | 13441篇 |
综合类 | 9篇 |
一般理论 | 21篇 |
预防医学 | 3985篇 |
眼科学 | 1212篇 |
药学 | 5391篇 |
中国医学 | 1006篇 |
肿瘤学 | 6889篇 |
出版年
2023年 | 14篇 |
2022年 | 29篇 |
2021年 | 1218篇 |
2020年 | 5010篇 |
2019年 | 10768篇 |
2018年 | 10021篇 |
2017年 | 11398篇 |
2016年 | 12035篇 |
2015年 | 11864篇 |
2014年 | 11733篇 |
2013年 | 12194篇 |
2012年 | 3899篇 |
2011年 | 3813篇 |
2010年 | 8793篇 |
2009年 | 5159篇 |
2008年 | 1860篇 |
2007年 | 703篇 |
2006年 | 750篇 |
2005年 | 536篇 |
2004年 | 552篇 |
2003年 | 575篇 |
2002年 | 675篇 |
2001年 | 744篇 |
2000年 | 667篇 |
1999年 | 238篇 |
1998年 | 15篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 6篇 |
1992年 | 13篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 12篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
61.
Melatonin reduces oxidative stress and improves vascular function in pulmonary hypertensive newborn sheep
下载免费PDF全文
![点击此处可从《Journal of pineal research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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
62.
Spontaneous generation of functional osteoclasts from synovial fluid mononuclear cells as a model of inflammatory osteoclastogenesis
下载免费PDF全文
![点击此处可从《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stinne R. Greisen Halldór Bjarki Einarsson Malene Hvid Ellen‐Margrethe Hauge Bent Deleuran Tue Wenzel Kragstrup 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2015,123(9):779-786
In osteoimmunology, osteoclastogenesis is understood in the context of the immune system. Today, the in vitro model for osteoclastogenesis necessitates the addition of recombinant human receptor activator of nuclear factor kappa‐B ligand (RANKL) and macrophage colony‐stimulating factor (M‐CSF). The peripheral joints of patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) are characterized by an immune‐mediated inflammation that can lead to bone destruction. Here, we evaluate spontaneous in vitro osteoclastogenesis in cultures of synovial fluid mononuclear cells (SFMCs) activated only in vivo. SFMCs were isolated and cultured for 21 days at 0.5–1.0 × 106 cells/mL in culture medium. SFMCs and healthy control peripheral blood monocytes were cultured with RANKL and M‐CSF as controls. Tartrate‐resistant acid phosphatase (TRAP) positive multinucleated cells were found in the SFMC cultures after 21 days. These cells expressed the osteoclast genes calcitonin receptor, cathepsin K, and integrin β3, formed lacunae on dentin plates and secreted matrix metalloproteinase 9 (MMP9) and TRAP. Adding RANKL and M‐CSF potentiated this secretion. In conclusion, we show that SFMCs from inflamed peripheral joints can spontaneously develop into functionally active osteoclasts ex vivo. Our study provides a simple in vitro model for studying inflammatory osteoclastogenesis. 相似文献
63.
64.
PNPLA3 gene polymorphism and response to lifestyle modification in patients with nonalcoholic fatty liver disease
下载免费PDF全文
![点击此处可从《Journal of gastroenterology and hepatology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
65.
Iria Montero Prez Laura Rodríguez‐Pazos Adriana lvarez‐Prez MªMercedes Pereiro Ferreirs Carlos Aliste Jose Manuel Suarez‐Pearanda Jaime Toribio 《Journal of cutaneous pathology》2015,42(11):889-893
Classical Kaposi sarcoma (KS) usually appears on lower extremities accompanied or preceded by local lymphedema. However, the development in areas of chronic lymphedema of the arms following mastectomy, mimicking a Stewart–Treves syndrome, has rarely been described. We report an 81‐year‐old woman who developed multiple, erythematous to purple tumors, located on areas of post mastectomy lymphedema. Histopathological examination evidenced several dermal nodules formed by spindle‐shaped cells that delimitated slit‐like vascular spaces with some red cell extravasation. Immunohistochemically, the human herpesvirus type 8 (HHV‐8) latent nuclear antigen‐1 was detected in the nuclei of most tumoral cells confirming the diagnosis of KS. Lymphedema could promote the development of certain tumors by altering immunocompetence. Although angiosarcoma (AS) is the most frequent neoplasia arising in the setting of chronic lymphedema, other tumors such as benign lymphangiomatous papules (BLAP) or KS can also develop in lymphedematous limbs. It is important to establish the difference between AS and KS because their prognosis and treatment are very different. Identification by immunohistochemistry of HHV‐8 is useful for the distinction between KS and AS or BLAP. 相似文献
66.
Tien‐Yao Tsai Iat‐Lon Leong Ka‐Shun Cheng Lian‐Ru Shiao Tzu‐Hui Su Kar‐Lok Wong Paul Chan Yuk‐Man Leung 《Fundamental & clinical pharmacology》2019,33(1):52-62
A pathological feature in atherosclerosis is the dysfunction and death of vascular endothelial cells (EC). Oxidized low‐density lipoprotein (LDL), known to accumulate in the atherosclerotic arterial walls, impairs endothelium‐dependent relaxation and causes EC apoptosis. A major bioactive ingredient of the oxidized LDL is lysophosphatidylcholine (LPC), which at higher concentrations causes apoptosis and necrosis in various EC. There is hitherto no report on LPC‐induced cytotoxicity in brain EC. In this work, we found that LPC caused cytosolic Ca2+ overload, mitochondrial membrane potential decrease, p38 activation, caspase 3 activation and eventually apoptotic death in mouse cerebral bEND.3 EC. In contrast to reported reactive oxygen species (ROS) generation by LPC in other EC, LPC did not trigger ROS formation in bEND.3 cells. Pharmacological inhibition of p38 alleviated LPC‐inflicted cell death. We examined whether heparin could be cytoprotective: although it could not suppress LPC‐triggered Ca2+ signal, p38 activation and mitochondrial membrane potential drop, it did suppress LPC‐induced caspase 3 activation and alleviate LPC‐inflicted cytotoxicity. Our data suggest LPC apoptotic death mechanisms in bEND.3 might involve mitochondrial membrane potential decrease and p38 activation. Heparin is protective against LPC cytotoxicity and might intervene steps between mitochondrial membrane potential drop/p38 activation and caspase 3 activation. 相似文献
67.
M.‐Q. Man L. Ye L. Hu S. Jeong P. M. Elias C. Lv 《Clinical and experimental dermatology》2019,44(6):654-657
While therapeutic approaches for psoriasis are widely available, preventive regimens are lacking. We aimed to determine whether improvements in epidermal function could prevent psoriasis relapse. Two self‐controlled cohort studies were designed, enrolling two cohorts of patients with psoriasis (n = 30 and n = 60) to be treated topically with an in‐house‐prepared emollient or ATOPALM® cream applied twice daily to one forearm for 20 and 30 days, respectively, while the same sites on the contralateral arm served as the untreated control. Epidermal function on both arms was assessed prior to and at the end of the trials. Delayed relapse on the treated arm was seen in 54.5% and 71% of patients in the first and second cohort, respectively. The time of psoriatic relapse correlated with the extent of abnormalities in baseline epidermal function. These results suggest that improvements in epidermal function with topical emollients can prevent/attenuate the development of psoriasis. 相似文献
68.
69.
70.
Luis Veloza Cristina Teixido Natalia Castrejon Fina Climent Ana Carri Marta Marginet Davide Soldini Blanca Gonzlez‐Farr Inmaculada Ribera‐Cortada Armando Lopez‐Guillermo Eva Gonzlez‐Barca Adriana Sierra Mileyka Herrera Cndida Gmez Adriana Garcia Olga Balagu Elias Campo Antonio Martinez 《Histopathology》2019,75(6):799-812