全文获取类型
收费全文 | 15056篇 |
免费 | 757篇 |
国内免费 | 73篇 |
专业分类
耳鼻咽喉 | 269篇 |
儿科学 | 298篇 |
妇产科学 | 316篇 |
基础医学 | 2063篇 |
口腔科学 | 1617篇 |
临床医学 | 871篇 |
内科学 | 3391篇 |
皮肤病学 | 253篇 |
神经病学 | 1238篇 |
特种医学 | 280篇 |
外科学 | 2221篇 |
综合类 | 65篇 |
一般理论 | 4篇 |
预防医学 | 1181篇 |
眼科学 | 347篇 |
药学 | 704篇 |
中国医学 | 109篇 |
肿瘤学 | 659篇 |
出版年
2024年 | 6篇 |
2023年 | 106篇 |
2022年 | 250篇 |
2021年 | 583篇 |
2020年 | 330篇 |
2019年 | 426篇 |
2018年 | 536篇 |
2017年 | 285篇 |
2016年 | 365篇 |
2015年 | 540篇 |
2014年 | 743篇 |
2013年 | 830篇 |
2012年 | 1244篇 |
2011年 | 1485篇 |
2010年 | 758篇 |
2009年 | 635篇 |
2008年 | 1107篇 |
2007年 | 1096篇 |
2006年 | 1044篇 |
2005年 | 880篇 |
2004年 | 776篇 |
2003年 | 643篇 |
2002年 | 566篇 |
2001年 | 60篇 |
2000年 | 52篇 |
1999年 | 45篇 |
1998年 | 64篇 |
1997年 | 46篇 |
1996年 | 41篇 |
1995年 | 36篇 |
1994年 | 32篇 |
1993年 | 31篇 |
1992年 | 24篇 |
1991年 | 18篇 |
1990年 | 11篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 14篇 |
1983年 | 16篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 12篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1975年 | 4篇 |
1971年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Dalton Luiz Schiessel Ricardo K. Yamazaki Marcelo Kryczyk Isabela Coelho de Castro Adriana A. Yamaguchi Danielle C. T. Pequito 《Nutrition and cancer》2016,68(8):1369-1380
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO. 相似文献
3.
4.
Die Anaesthesiologie - Simulationstraining ist für die Notfallmedizin unverzichtbar, insbesondere in Hinsicht auf eine verbesserte Patientensicherheit. Methoden und Technologien umfassen ein... 相似文献
5.
6.
7.
John Lennon Silva Cunha Amanda Almeida Leite Thamiris de Castro Abrantes Lorena Passoni Vervloet Thayn Melo de Lima Morais Gerson de Oliveira Paiva Neto Tatiana Nayara Librio Kimura Snia Maria Soares Ferreira Ricardo Luiz Cavalcanti de Albuquerque‐Júnior Aline Corrêa Abraho Mario Jos Romaach Bruno Augusto Benevenuto de Andrade Oslei Paes de Almeida Ciro Dantas Soares 《Journal of cutaneous pathology》2021,48(1):24-33
8.
Age-related bone loss has been associated with high levels of marrow adipogenesis. Estrogens (E2) are known to regulate the differentiation of marrow precursors into osteoblasts, however, their role in bone marrow adipogenesis
remain unknown. E2 regulate adipocyte differentiation in subcutaneous and visceral fat through interaction with other nuclear receptors. This
interaction has not been assessed in bone marrow adipocytes in vivo. In this study, we compared two groups of animals, young
and old, after either oophorectomy (OVX) or oophorectomy plus E2 (OVX + E2) replacement. We found that absence of E2 was associated with higher levels of PPARγ and lower levels of Sirt1 most significantly in the old group. In addition, old
mice responded better to E2 replacement in terms of reducing adipogenesis and PPARγ expression as well as increasing levels of Sirt1 expression. Our
findings represent a new understanding of the role of E2 in age-related bone loss, which could be mediated through the regulation of Sirt1 expression within the bone marrow. In addition,
this evidence suggests that old individuals may show a better response to E2 administration in terms of reverting the high levels of marrow fat seen in age-related bone loss. 相似文献
9.
10.
Luiz Fernando Tomazinho Mario J Avila-Campos 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,103(2):285-288
Black-pigmented anaerobic rods such as Prevotella spp. and Porphyromonas spp. are involved in the etiology and perpetuation of endodontic infections. The aim of this study was to evaluate the prevalence of these species in chronic endodontic infections by using culture and polymerase chain reaction (PCR) techniques. Samples of 100 patients with root canals displaying chronic endodontic infections were obtained by sterilized paper points. Bacterial identification was performed by using culture and PCR techniques. By culture, in 33% of the samples, P. intermedia-P. nigrescens (75.8%), P. gingivalis (27.3%), and P. endodontalis (9.1%) were identified, and by PCR 60% of the samples harbored P. nigrescens (43.3%), P. gingivalis (43.3%), P. intermedia (31.7%), and P. endodontalis (23.3%). The presence of these black-pigmented anaerobic rods alone or in association in chronic endodontic infections seems to be frequent. PCR is a very sensitive technique for detecting DNA from bacterial cells. Culturing is only able to reveal living bacteria and is less sensitive for the identification of low numbers of bacterial cells. 相似文献