全文获取类型
收费全文 | 76740篇 |
免费 | 6953篇 |
国内免费 | 2204篇 |
专业分类
耳鼻咽喉 | 573篇 |
儿科学 | 1010篇 |
妇产科学 | 227篇 |
基础医学 | 6360篇 |
口腔科学 | 3159篇 |
临床医学 | 10190篇 |
内科学 | 14168篇 |
皮肤病学 | 801篇 |
神经病学 | 2202篇 |
特种医学 | 3249篇 |
外国民族医学 | 2篇 |
外科学 | 16218篇 |
综合类 | 11285篇 |
现状与发展 | 12篇 |
一般理论 | 3篇 |
预防医学 | 3672篇 |
眼科学 | 420篇 |
药学 | 5194篇 |
63篇 | |
中国医学 | 5598篇 |
肿瘤学 | 1491篇 |
出版年
2024年 | 210篇 |
2023年 | 1742篇 |
2022年 | 2211篇 |
2021年 | 4108篇 |
2020年 | 3963篇 |
2019年 | 3502篇 |
2018年 | 3287篇 |
2017年 | 3613篇 |
2016年 | 3347篇 |
2015年 | 3336篇 |
2014年 | 5709篇 |
2013年 | 6363篇 |
2012年 | 4543篇 |
2011年 | 5007篇 |
2010年 | 3914篇 |
2009年 | 3583篇 |
2008年 | 3309篇 |
2007年 | 3419篇 |
2006年 | 3017篇 |
2005年 | 2482篇 |
2004年 | 2109篇 |
2003年 | 1761篇 |
2002年 | 1506篇 |
2001年 | 1336篇 |
2000年 | 1088篇 |
1999年 | 916篇 |
1998年 | 743篇 |
1997年 | 737篇 |
1996年 | 610篇 |
1995年 | 585篇 |
1994年 | 506篇 |
1993年 | 434篇 |
1992年 | 361篇 |
1991年 | 287篇 |
1990年 | 234篇 |
1989年 | 230篇 |
1988年 | 199篇 |
1987年 | 184篇 |
1986年 | 165篇 |
1985年 | 229篇 |
1984年 | 171篇 |
1983年 | 140篇 |
1982年 | 155篇 |
1981年 | 150篇 |
1980年 | 82篇 |
1979年 | 68篇 |
1978年 | 67篇 |
1977年 | 55篇 |
1976年 | 54篇 |
1975年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
Gautam Chakrabarty Mayank Vashishtha Daniel Leeder 《Journal of Clinical Orthopaedics and Trauma》2015,6(2):108-112
Polyethylene (PE) has been used extensively in knee arthroplasty since the mid 20th century. Progress in material manufacturing and processing has led to newer polyethylenes over last few decades with different material properties. It has been established that PE wear in knee arthroplasty causes particle induced osteolysis which is the main reason for late failure and requires revision surgery. Although there are various causes of wear, the properties of PE have long been a matter of investigation as a contributory factor. The advent of newer highly cross linked PE has been shown to improve wear rates in hip arthroplasty but the benefits have not been shown to be of the same degree in knee arthroplasty. The laboratory and clinical studies so far are limited and slightly conflicting in their conclusions. The risks of using highly cross linked PE in knee arthroplasty include tibial post fracture, disruption of locking mechanism, liner fracture which can lead to increased wear and osteolysis. The current evidence suggests that highly cross linked polyethylenes should be used with caution and only considered in younger active patients. The results of a recently completed randomized trial to compare the conventional with high molecular weight PE in knee arthroplasty are awaited. 相似文献
34.
Qiaojie Wang Karan Goswami Noam Shohat Arash Aalirezaie Jorge Manrique Javad Parvizi 《The Journal of arthroplasty》2019,34(5):947-953
Background
Whether prolonged operative time is an independent risk factor for subsequent surgical site infection (SSI) and periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant and underexplored issue. The aim of this study is to investigate the association between operative time and the risk of subsequent SSI and PJI in patients undergoing primary TJA.Methods
We retrospectively reviewed 17,342 primary unilateral total knee arthroplasty and total hip arthroplasty performed at a single institution between 2005 and 2016, with a minimum follow-up of 1 year. A multivariate logistic regression model was conducted to identify the association between operative time and the development of SSI within 90 days and PJI within 1 year.Results
Overall, the incidence of 90-day SSI and 1-year PJI was 1.2% and 0.8%, respectively. Patients with an operative time of >90 minutes had a significantly higher incidence of SSI and PJI (2.1% and 1.4%, respectively) compared to cases lasting between 60 and 90 minutes (1.1% and 0.7%), and those lasting ≤60 minutes (0.9% and 0.7%, P < .01). In the multivariate model, the risk for infection increased by an odds ratio of 1.346 (95% confidential interval 1.114-1.627) for 90-day SSI and 1.253 (95% confidential interval 1.060-1.481) for 1-year PJI for each 20-minute increase in operative time.Conclusion
In patients undergoing primary TJA, each 20-minute increase in operative time was associated with nearly a 25% increased risk of subsequent PJI. We advocate that surgeons pay close attention to this underappreciated risk factor while maintaining safe operative practices, which minimize unnecessary steps and wasted time in the operating room. 相似文献35.
《Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society》2020,28(11):1412-1426
36.
37.
38.
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
39.
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
40.