全文获取类型
收费全文 | 7264篇 |
免费 | 485篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 75篇 |
儿科学 | 184篇 |
妇产科学 | 138篇 |
基础医学 | 986篇 |
口腔科学 | 954篇 |
临床医学 | 534篇 |
内科学 | 1532篇 |
皮肤病学 | 135篇 |
神经病学 | 469篇 |
特种医学 | 265篇 |
外科学 | 750篇 |
综合类 | 47篇 |
一般理论 | 1篇 |
预防医学 | 833篇 |
眼科学 | 129篇 |
药学 | 508篇 |
中国医学 | 74篇 |
肿瘤学 | 188篇 |
出版年
2023年 | 72篇 |
2022年 | 182篇 |
2021年 | 246篇 |
2020年 | 195篇 |
2019年 | 241篇 |
2018年 | 318篇 |
2017年 | 196篇 |
2016年 | 211篇 |
2015年 | 257篇 |
2014年 | 346篇 |
2013年 | 398篇 |
2012年 | 569篇 |
2011年 | 658篇 |
2010年 | 318篇 |
2009年 | 301篇 |
2008年 | 400篇 |
2007年 | 457篇 |
2006年 | 354篇 |
2005年 | 283篇 |
2004年 | 208篇 |
2003年 | 171篇 |
2002年 | 179篇 |
2001年 | 131篇 |
2000年 | 113篇 |
1999年 | 119篇 |
1998年 | 40篇 |
1997年 | 34篇 |
1996年 | 32篇 |
1995年 | 27篇 |
1994年 | 41篇 |
1993年 | 28篇 |
1992年 | 52篇 |
1991年 | 57篇 |
1990年 | 37篇 |
1989年 | 54篇 |
1988年 | 37篇 |
1987年 | 47篇 |
1986年 | 42篇 |
1985年 | 33篇 |
1984年 | 32篇 |
1983年 | 27篇 |
1982年 | 23篇 |
1981年 | 19篇 |
1979年 | 17篇 |
1977年 | 19篇 |
1976年 | 16篇 |
1975年 | 20篇 |
1970年 | 20篇 |
1968年 | 20篇 |
1967年 | 13篇 |
排序方式: 共有7802条查询结果,搜索用时 15 毫秒
91.
Paula C. Eterovick Ryan Franckowiak Cibele Velloso-Rodrigues Jo?o Bruno G. C. Santos Rauber S. Garcia Josiane A. Gomes 《Conservation Genetics Resources》2012,4(2):483-485
We report 14 microsatellite loci for Bokermmanohyla saxicola, a frog species endemic of the Espinha?o mountain chain in southeastern Brazil. We used a sample of 53 individuals from a single locality to characterize these polymorphic loci. Number of alleles per locus ranged from 3 to 17, observed heterozygosity and expected heterozygosity ranged from 0.125 to 0.925 and from 0.137 to 0.907, respectively. These loci will be useful to understand population structure of this frog throughout its distribution, aiding to landscape conservation planning in the Espinha?o, considered a center of endemism and a priority area for conservation. 相似文献
92.
93.
94.
Rui Caetano-Oliveira Marcos António Gomes Ana Margarida Abrantes Edgar Tavares-Silva Marco Carvalho Oliveira Mafalda Laranjo Débora Basílio Queirós João Casalta-Lopes Salomé Pires Lina Carvalho Rosa Gouveia Paulo Rodrigues Santos Denise Gonçalves Priolli José Guilherme Tralhão Maria Filomena Botelho 《Pathophysiology》2018,25(2):89-99
Colorectal cancer (CRC) is the second most frequent and fatal cancer in Western countries. Understanding its biology with different incidence along the colon and rectum, genetic profile and how these factors contribute to local/distant progression, has been hampered by the lack of a suitable CRC model.We report a reproducible model, using human CRC cell lines (CL) (WiDr, LS1034, C2BBe1) injected (1?×?107 cells/animal) in RNU rats (n?=?55) which underwent cecostomy and descending colostomy with mucosal-cutaneous fistula of the sigmoid colon. CL were characterized by immunohistochemistry: CK20, CDX2, P53, vimentin, Ki67, CD44, CD133, E-cadherin, β-catenin and CEA; cancer stem cells-immune system interaction was studied and tumor progression was assessed with nuclear medicine imaging (99mTc-MIBI).Animals developed locally invasive tumors and with WiDr neural invasion was registered. Cancer stem cells were detected in WiDr (CD44 positive). All the cell lines stimulated the immune system, being WiDr the most aggressive. Imaging studies demonstrated tumor uptake.With this CRC model we can study the microenvironment role and tumor-stroma interactions. All CL developed primary disease, but only the WiDR established neural invasion which may represent a metastatic pathway. This model can help unveiling the underlying metastatic mechanisms, and ultimately test better therapeutic approaches for CRC. 相似文献
95.
Alessandro Schuffner Ana Paula Lisboa Vinicius Bonato da Rosa Monica Maria Gomes da Silva 《The Brazilian journal of infectious diseases》2011,15(4):397-398
Due to HIV care improvement, discordant couples more frequently seek help in order to conceive their own biological child. Besides the advance of antiretroviral therapy, unprotected intercourse is not a complete safe option, carrying a low but still present risk of HIV transmission. We report 10 serodiscordant couples in whom the male partner is HIV positive, submitted to sperm washing and intrauterine insemination. The procedure resulted in four pregnancies and no HIV transmission to mother or child was observed. Techniques of assisted reproduction can help HIV discordant couples to conceive biological offspring and is a safer option than unprotected intercourse. 相似文献
96.
Nestor Rodrigues de Oliveira Neto M.D. George Cobe Fonseca M.D. Gustavo Gomes Torres M.D. Marcos Antonio Pinheiro M.D. George Barreto Miranda M.D. 《Annals of noninvasive electrocardiology》2011,16(1):41-48
Background: Few electrocardiographic parameters beyond the QRS duration were studied with regard to the correlation with mechanical dyssynchrony. This study aims to analyze the correlation between electrocardiographic parameters and mechanical dyssynchrony in patients with symptomatic heart failure (HF) and left bundle branch block (LBBB). Methods: Patients with HF, ejection fraction ≤ 35%, and QRS interval ≥ 120 ms with a LBBB were prospectively studied. We analyzed the correlation between electrocardiographic parameters (QRS duration, R voltage in limb leads, S voltage in precordial leads, Sokolow and Cornell indexes, QRS axis deviation, and QRS notches in lateral and inferior leads) and mechanical dyssynchrony measured by tissue Doppler imaging (TDI). Results: A group of 50 patients were studied, 60% male, 78% with nonischemic cardiomyopathy, NYHA Class III–IV (86%), and ejection fraction of 0.22 ± 0.6. Intra‐ and interventricular dyssynchrony occurred in 68% and 74% of patients, respectively. The S amplitude in precordial leads and the Sokolow and Cornel indexes show a weak correlation with the degree of dyssynchrony. In the patients with QRS notching in the lateral and inferior leads, we observed significantly greater prevalence of intraventricular dyssynchrony, with sensitivity and specificity of 85% and 56%, respectively, for notches in lateral leads. The QRS duration presents moderate correlation with the degree of both intraventricular (r = 0.48) and interventricular dyssynchrony (r = 0.46). Conclusion: The following electrocardiographic parameters were related to the degree of mechanical dyssynchrony: QRS duration and notches in QRS. In addition, the patients tend to have highest S amplitude in precordial leads. Ann Noninvasive Electrocardiol 2011;16(1):41–48 相似文献
97.
Pedro Gouveia Catarina Silva Fátima Magalhães Claúdia Santos Emanuel Guerreiro Filipe Santos Teixeira Gomes 《International journal of surgery case reports》2013,4(5):524-527
INTRODUCTIONAngiosarcoma is a very rare entity of soft tissue neoplasm with an aggressive and destructive biological behavior. Thyroid angiosarcoma is usually reported in Alpine regions, with only exceptionally rare cases arising in non-mountainous areas. In the Alpine regions it constitutes 2–10% of all malignant thyroid tumors.PRESENTATION OF CASEWe report a case of a thyroid non-Alpine angiosarcoma in a 71-year-old female with a 10 years old multinodular goiter. The cervical mass underwent rapid growth in the last year, and she was referred for surgical treatment. A 15 cm mass was found on the right side of the neck invading adjacent tissues and displacing the trachea without obvious invasion of this organ. Fine needle aspiration cytology showed “carcinoma”. Lung metastasis were present. Although difficult, total thyroidectomy was possible with resection of an esophageal implant. Post-operatively, she had respiratory failure that eventually recovered, but, on 39th post-operative day, she died of violent hemoptysis, probably due to invasion by mediastinal metastasis.DISCUSSIONA clear distinction between angiosarcoma and anaplastic carcinoma of the thyroid is considerably difficult, despite treatments and prognosis are practically the same. However, in recent years, a thyroid malignancy exhibiting phenotypical features of endothelial differentiation was described. Keratin positivity cannot be reported as necessarily indicative of epithelial differentiation.CONCLUSIONOptimal treatment for thyroid angiosarcoma remains unclear, not only because the prognosis is poor, despite multimodal therapeutic efforts, but also because it is a very rare entity. 相似文献
98.
Lívia Alves Amaral Santos Talles Bazeia Lima Laís Augusti Letícia de Campos Franzoni Fabio da Silva Yamashiro Fernanda Bolfi Vânia dos Santos Nunes Mariana de Souza Dorna Cássio Vieira de Oliveira Carlos Antonio Caramori Giovanni Faria Silva Fernando Gomes Romeiro 《Journal of gastroenterology and hepatology》2016,31(1):229-234
99.
Thiago Martins Lara Ludhmila Abrahao Hajjar Juliano Pinheiro de Almeida Julia Tizue Fukushima Carmem Silvia Valente Barbas Adriano Rogerio Baldacin Rodrigues Emilia Nozawa Maria Ignes Zanetti Feltrim Elisangela Almeida Vera Coimbra Eduardo Osawa Rafael de Moraes Ianotti Alcino Costa Leme Fabio Biscegli Jatene Jose Otavio Costa Auler-Jr. Filomena Regina Barbosa Gomes Galas 《Clinics (S?o Paulo, Brazil)》2013,68(1):33-38
100.
Sandhra M. Carvalho Agda A.R. Oliveira Camila A. Jardim Carolina B.S. Melo Dawidson A. Gomes Maria de Fátima Leite Marivalda M. Pereira 《Journal of tissue engineering and regenerative medicine》2012,6(10):813-821
Cementum is a mineralized tissue that lines the surface of the tooth root enabling attachment of the periodontal ligament to the root and surrounding alveolar bone. Studies examining the mechanisms involved in the formation of root cementum have been hindered by an inability to isolate and culture the cells required for cementum production (cementoblasts). This study isolated and characterized cementoblast cells derived from rat molar periodontal ligament. It was observed that the isolated cells expressed F‐Spondin, a cementoblast marker, while F‐Spondin expression was not observed in the cells of other tissues such as gingival fibroblasts and osteoblasts. As expected, the isolated cementoblast cells also expressed osteocalcin (OC), bone sialoprotein (BSP), alkaline phosphatase (ALP), and type I collagen, demonstrating the presence of mineralized tissues genes in cementoblast cells. These cells showed high ALP activity and calcified nodule formation in vitro. Since cementogenesis could be a critical event for regeneration of periodontal tissues, this study investigated whether bioactive glass particles could affect the proliferation of cementoblasts since they are known to enhance osteoblast proliferation. It was found that the ionic products from bioactive glass nanoparticles increased cementoblast viability, mitochondrial activity, and induced cell proliferation. Together, these results show the characterization of cementoblast cells from rat molar periodontal ligament. Additionally, it was shown that bioactive glass nanoparticles induced cementoblast to proliferate, indicating that they could be a potential material for use in cement regeneration through tissue engineering. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献