全文获取类型
收费全文 | 2351篇 |
免费 | 180篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 71篇 |
妇产科学 | 39篇 |
基础医学 | 322篇 |
口腔科学 | 97篇 |
临床医学 | 198篇 |
内科学 | 606篇 |
皮肤病学 | 62篇 |
神经病学 | 239篇 |
特种医学 | 63篇 |
外科学 | 227篇 |
综合类 | 8篇 |
一般理论 | 1篇 |
预防医学 | 174篇 |
眼科学 | 18篇 |
药学 | 211篇 |
中国医学 | 8篇 |
肿瘤学 | 185篇 |
出版年
2024年 | 3篇 |
2023年 | 30篇 |
2022年 | 54篇 |
2021年 | 125篇 |
2020年 | 60篇 |
2019年 | 85篇 |
2018年 | 84篇 |
2017年 | 72篇 |
2016年 | 85篇 |
2015年 | 94篇 |
2014年 | 119篇 |
2013年 | 119篇 |
2012年 | 202篇 |
2011年 | 193篇 |
2010年 | 107篇 |
2009年 | 83篇 |
2008年 | 157篇 |
2007年 | 156篇 |
2006年 | 146篇 |
2005年 | 135篇 |
2004年 | 122篇 |
2003年 | 112篇 |
2002年 | 87篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 12篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1954年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有2544条查询结果,搜索用时 15 毫秒
31.
32.
33.
Mallika Ghosh Claire Gerber M. Mamunur Rahman Kaitlyn M. Vernier Flavia E. Pereira Jaganathan Subramani Leslie A. Caromile Linda H. Shapiro 《Immunology》2014,142(4):636-647
CD13/Aminopeptidase N is a transmembrane metalloproteinase that is expressed in many tissues where it regulates various cellular functions. In inflammation, CD13 is expressed on myeloid cells, is up‐regulated on endothelial cells at sites of inflammation and mediates monocyte/endothelial adhesion by homotypic interactions. In animal models the lack of CD13 alters the profiles of infiltrating inflammatory cells at sites of ischaemic injury. Here, we found that CD13 expression is enriched specifically on the pro‐inflammatory subset of monocytes, suggesting that CD13 may regulate trafficking and function of specific subsets of immune cells. To further dissect the mechanisms regulating CD13‐dependent trafficking we used the murine model of thioglycollate‐induced sterile peritonitis. Peritoneal monocytes, macrophages and dendritic cells were significantly decreased in inflammatory exudates from global CD13KO animals when compared with wild‐type controls. Furthermore, adoptive transfer of wild‐type and CD13KO primary myeloid cells, or wild‐type myeloid cells pre‐treated with CD13‐blocking antibodies into thioglycollate‐challenged wild‐type recipients demonstrated fewer CD13KO or treated cells in the lavage, suggesting that CD13 expression confers a competitive advantage in trafficking. Similarly, both wild‐type and CD13KO cells were reduced in infiltrates in CD13KO recipients, confirming that both monocytic and endothelial CD13 contribute to trafficking. Finally, murine monocyte cell lines expressing mouse/human chimeric CD13 molecules demonstrated that the C‐terminal domain of the protein mediates CD13 adhesion. Therefore, this work verifies that the altered inflammatory trafficking in CD13KO mice is the result of aberrant myeloid cell subset trafficking and further defines the molecular mechanisms underlying this regulation. 相似文献
34.
Rossella Gioco Daniela Corona Burcin Ekser Lidia Puzzo Gaetano Inserra Flavia Pinto Chiara Schipa Francesca Privitera Pierfrancesco Veroux Massimiliano Veroux 《World journal of gastroenterology : WJG》2020,26(38):5797-5811
Gastrointestinal complications are common after renal transplantation, and they have a wide clinical spectrum, varying from diarrhoea to post-transplant inflammatory bowel disease(IBD). Chronic immunosuppression may increase the risk of post-transplant infection and medication-related injury and may also be responsible for IBD in kidney transplant re-cipients despite immunosuppression. Differentiating the various forms of post-transplant colitis is challenging, since most have similar clinical and histological features. Drug-related colitis are the most frequently encountered colitis after kidney transplantation, particularly those related to the chronic use of mycophenolate mofetil, while de novo IBDs are quite rare. This review will explore colitis after kidney transplantation, with a particular focus on different clinical and histological features, attempting to clearly identify the right treatment, thereby improving the final outcome of patients. 相似文献
35.
MA Lima A Aversa P Maranhão-Filho GA Lima A Curi CA Schmaltz FM Santanna 《Revista do Instituto de Medicina Tropical de S?o Paulo》2012,54(4):229-230
Brain tuberculomas account for 10-20% of space occupying brain lesions in developing countries. Most lesions are observed at time of tuberculosis diagnosis or soon after starting treatment. We herein describe a 32 year-old patient with a 14-month history of headache and progressive visual loss. Her past medical history revealed pulmonary tuberculosis treated eight years before. A brain MRI showed a T1- and T2-weighted isointense contrast-enhancing lesion in the optic chiasm. A presumptive diagnosis of optochiasmatic tuberculoma was made and isoniazid, rifampin, pyrazinamide, and ethambutol were started. Despite treatment, the patient evolved to blindness. The prompt recognition of this condition is extremely important since the presence of optochiasmal enhancement is associated with blindness in patients with tuberculosis. 相似文献
36.
Monica Pires Ribeiro Sergio Augusto Lopes de Souza Flavia Paiva Proen?a Lobo Lopes Paulo Henrique Rosado-de-Castro Lea Mirian Barbosa da Fonseca Bianca Gutfilen 《Clinics (S?o Paulo, Brazil)》2013,68(3):283-289
OBJECTIVE:
Mammography has been established as the gold standard for the detection of breast cancer, and imaging techniques such as ultrasonography, magnetic resonance imaging, scintigraphy and positron emission tomography may be useful to improve its sensitivity and specificity. The objective of this study with breast scintigraphy was to evaluate the uptake of 99mTc-thymine in mammary lesions.METHODS:
A total of 45 patients were included in this study. Thirty-three patients (73%) were subjected to surgery or percutaneous biopsy, providing histopathological data. The other 12 patients who remained under surveillance received clinical examinations and biannual mammography with a normal follow-up of at least three years, the data from which were used for comparison with the scintimammography results.RESULTS:
The majority of patients (64.4%) had clinically impalpable lesions with a mammogram diagnosis of microcalcifications, impalpable nodules, or focal asymmetry. Of the studied lesions, 87% were smaller or equal to 20 mm in diameter, and 22% had malignant histopathological findings. Scintigraphy with 99mTc-thymine had a sensitivity of 70%, a specificity of 85.7%, positive and negative predictive values of 58.3% and 90.9%, respectively, and an accuracy of 82.2%.CONCLUSIONS:
The results of this study are consistent with those previously reported by other authors. The good specificity and high negative predictive value of this technique and the absence of uptake in the heart indicate that it may be a promising complementary method in clinical practice and that it may contribute to reducing unnecessary benign biopsies. 相似文献37.
38.
Ricardo Teles Flavia Teles Jorge Frias‐Lopez Bruce Paster Anne Haffajee 《Periodontology 2000》2013,62(1):95-162
Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. In the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best‐characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this article we will review how our comprehension of the structure and function of the subgingival microbiota has evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: (i) how the data obtained through molecular techniques have impacted our knowledge of the etiology of periodontal infections; (ii) the potential role of viruses in the etiopathogenesis of periodontal diseases; (iii) how concepts of microbial ecology have expanded our understanding of host–microbe interactions that might lead to periodontal diseases; (iv) the role of inflammation in the pathogenesis of periodontal diseases; and (v) the impact of these evolving concepts on therapeutic and preventive strategies to periodontal infections. We will conclude by reviewing how novel systems‐biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and hopefully lead to a better understanding of their mechanisms. 相似文献
39.
Adenilson de Souza da Fonseca Andre Luiz Mencalha Vera Maria Araújo de Campos Samara Cristina Ferreira Machado Antonio Augusto de Freitas Peregrino Mauro Geller Flavia de Paoli 《Lasers in medical science》2013,28(4):1077-1084
Special properties of laser light have led to its usefulness in many applications in therapy. Excitation of endogenous chromophores in biotissues and generation of free radicals could be involved in its biological effects. DNA lesions induced by free radicals are repaired by base excision repair pathway. In this work, we evaluated the expression of APE1 and OGG1 genes related to repair of DNA lesions induced by free radicals. Skin and muscle tissues of Wistar rats were exposed to low-intensity infrared laser at different fluences and frequencies. After laser exposition of 1 and 24 h, tissue samples were withdrawn for total RNA extraction, cDNA synthesis, and evaluation of APE1 and OGG1 gene expression by quantitative polymerase chain reaction. Data obtained show that laser radiation alters the expression of APE1 and OGG1 mRNA differently in skin and muscle tissues of Wistar rats depending of the fluence, frequency, and time after exposure. Our study suggests that low-intensity infrared laser affects expression of genes involved in repair of DNA lesions by base excision repair pathway. 相似文献
40.
Flavia Kazue Ibuki Alyne Simões José Nicolau Fernando Neves Nogueira 《Lasers in medical science》2013,28(3):911-918
The aim of the present study was to analyze the effect of low-power laser irradiation in the antioxidant enzymatic system of submandibular (SMG) and parotid (PG) salivary glands of streptozotocin-induced diabetic rats. The animals were randomly divided into six groups: three diabetic groups (D0, D5, and D20) and three non-diabetic groups (C0, C5, and C20), according to laser dose received (0, 5, and 20 J/cm2, respectively). Areas of approximately 1 cm2 were demarcated in the salivary glands (each parotid and both submandibular glands) and after irradiated according to Simões et.al. (Lasers Med Sci 24:202–208, 2009). A diode laser (660 nm/100 mW) was used, with laser beam spot of 0.0177 cm2. The group treated with 5 J/cm2 laser dose was subjected to irradiation for 1 min and 4 s (total irradiation time) and the group treated with 20 J/cm2 laser dose was subjected to irradiation for 4 min and 16 s. Twenty-four hours after irradiation the animals were euthanized and the salivary glands were removed for biochemical analysis. The total antioxidant values (TA), the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase enzymes were determined. SOD and CAT activities, as well as TA were higher in SMG of irradiated diabetic rats. However, in SMG of non-diabetic rats, laser irradiation decreased TA values and led to an increase in the CAT activity. In addition, there was a decrease in the activity of CAT in PG of diabetic and non-diabetic animals after laser irradiation. According to the results of the present study, low-power laser irradiation can affect the enzymatic antioxidant system of salivary glands of streptozotocin-induced diabetic rats. 相似文献