全文获取类型
收费全文 | 8222篇 |
免费 | 472篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 141篇 |
儿科学 | 253篇 |
妇产科学 | 130篇 |
基础医学 | 961篇 |
口腔科学 | 855篇 |
临床医学 | 594篇 |
内科学 | 1781篇 |
皮肤病学 | 178篇 |
神经病学 | 570篇 |
特种医学 | 306篇 |
外国民族医学 | 1篇 |
外科学 | 1119篇 |
综合类 | 74篇 |
预防医学 | 817篇 |
眼科学 | 115篇 |
药学 | 516篇 |
中国医学 | 42篇 |
肿瘤学 | 272篇 |
出版年
2023年 | 74篇 |
2022年 | 186篇 |
2021年 | 284篇 |
2020年 | 212篇 |
2019年 | 245篇 |
2018年 | 333篇 |
2017年 | 213篇 |
2016年 | 240篇 |
2015年 | 305篇 |
2014年 | 382篇 |
2013年 | 430篇 |
2012年 | 563篇 |
2011年 | 682篇 |
2010年 | 421篇 |
2009年 | 316篇 |
2008年 | 439篇 |
2007年 | 477篇 |
2006年 | 367篇 |
2005年 | 352篇 |
2004年 | 280篇 |
2003年 | 214篇 |
2002年 | 202篇 |
2001年 | 152篇 |
2000年 | 155篇 |
1999年 | 121篇 |
1998年 | 72篇 |
1997年 | 56篇 |
1996年 | 70篇 |
1995年 | 59篇 |
1994年 | 42篇 |
1993年 | 37篇 |
1992年 | 67篇 |
1991年 | 68篇 |
1990年 | 51篇 |
1989年 | 46篇 |
1988年 | 36篇 |
1987年 | 33篇 |
1986年 | 40篇 |
1985年 | 46篇 |
1984年 | 33篇 |
1983年 | 33篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 24篇 |
1979年 | 24篇 |
1978年 | 17篇 |
1976年 | 19篇 |
1971年 | 17篇 |
1969年 | 19篇 |
1968年 | 21篇 |
排序方式: 共有8725条查询结果,搜索用时 15 毫秒
1.
2.
Talita da Silva Mendes de Farias Ariclécio Cunha de Oliveira Sandra Andreotti Fernanda Gaspar do Amaral Patrícia Chimin André Ricardo Alves de Proença Francisco Leonardo Torres Leal Rogério Antonio Laurato Sertié Amanda Baron Campana Andressa Bolsoni Lopes Arnaldo Henrique de Souza José Cipolla‐Neto Fabio Bessa Lima 《Journal of pineal research》2015,58(3):251-261
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals. 相似文献
3.
4.
5.
6.
The performance of a tooth replacement by using a dental implant relies on the mechanical and biological capability of the anatomical substitute to restore lost physiological functions. The design of an implant device able to properly replace the physiological tooth requires the study of the load transfer mechanism at the implant-bone interface and the understanding of the relevance of the periodontal ligament (PDL) in this mechanism. The PDL is a connective soft tissue that provides the fixation of the tooth in its bone-socket and the attenuation of occlusal loads. It also provides the ground cells that are involved in the remodelling process, induced by a change in the stress-strain pattern of the alveolar bone and also in the cementum of the tooth root. The purpose of this study was to determine the PDL effects on the dynamic load transfer mechanism, from the tooth to the alveolar bone, evaluating the equivalent dynamic stiffness of the ligament structure. A porcine fresh mandible with a tooth was used within the study, applying an experimental procedure to identify the dynamic transmissibility of the entire system. The transmissibility function provided information about the stiffness and damping of the PDL, information that can assist the design of an improved dental implant system. 相似文献
7.
L Crespo J Graus F García-Hoz R Bárcena L Gil Grande V F Moreira J M Milicua J Sánchez J Blázquez 《Revista española de enfermedades digestivas》2007,99(11):667-670
Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques. 相似文献
8.
Marina H C G Magalh?es Cristiane Barbosa da Silveira Carla Ruffeil Moreira Marcelo Gusm?o Paraíso Cavalcanti 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,103(6):836-842
Mandibulofacial dysostosis (Treacher Collins Syndrome) is an autosomal dominant genetic disorder that probably derives from inhibition of the facial structures from the first and second branchial arches. The facial pattern of the syndrome is a convex facial profile with a prominent nose above a retruded chin. The eyes are deformed by antimongoloid slant of the palpebral fissures and facial bones are hypoplastic. The alterations are caused by mutation in gene 5q32-33.1, which encodes the nucleolar phosphoprotein treacle. Computed tomography images are able to demonstrate craniofacial bones, allowing the morphological analysis of these bones in individuals with complex deformities. The purpose of this paper is to present the results of a clinical and computed tomography investigation of two patients with Treacher Collins syndrome. 相似文献
9.
10.
Umadevi Sajjan PhD Jorge Moreira MD Mingyao Liu PhD Atul Humar MD Cecilia Chaparro MD Janet Forstner MD PhD Shaf Keshavjee MD 《The Journal of heart and lung transplantation》2004,23(12):235-1391
BACKGROUND: Lung infection with Burkholderia cepacia complex before lung transplantation in patients with cystic fibrosis is a major risk factor for decreased post-operative survival rates compared with those of patients colonized with the more common opportunistic pathogen Pseudomonas aeruginosa. Because adherence to mucosal surfaces is an important initial step in infection, we investigated the use of non-toxic neutral polysaccharides and a sugar alcohol to prevent adherence of B cepacia complex to allograft airway epithelium. METHODS: We used human airway explants prepared from donor tracheobronchial tissue to test the effect of dextrans and xylitol in inhibiting the binding of Burkholderia cepacia complex. We used immunofluorescence and electron microscopy to determine the distribution of bacteria in the explants. RESULTS: Burkholderia cepacia complex bound to the explants and was found only in the surface mucus layer. Dextran 40 kd applied before adding the bacteria decreased the number of bound organisms by 80% to 99%. Smaller molecular mass dextrans (4 and 20 kd) were ineffective. Xylitol inhibited bacterial binding by 67% to 85%. Both agents seemed to decrease the thickness of the surface mucus, suggesting that they may indirectly inhibit bacterial binding by removing adherent surface mucus. CONCLUSIONS: Treating donor lungs with dextran 40 kd or xylitol before (and possibly after) surgery may inhibit the adherence of Burkholderia cepacia complex to airways and may prevent or decrease subsequent infection of the allografts. 相似文献