全文获取类型
收费全文 | 8349篇 |
免费 | 614篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 176篇 |
妇产科学 | 167篇 |
基础医学 | 1438篇 |
口腔科学 | 196篇 |
临床医学 | 818篇 |
内科学 | 1840篇 |
皮肤病学 | 271篇 |
神经病学 | 952篇 |
特种医学 | 243篇 |
外科学 | 843篇 |
综合类 | 25篇 |
一般理论 | 5篇 |
预防医学 | 534篇 |
眼科学 | 114篇 |
药学 | 642篇 |
中国医学 | 12篇 |
肿瘤学 | 695篇 |
出版年
2024年 | 18篇 |
2023年 | 132篇 |
2022年 | 238篇 |
2021年 | 394篇 |
2020年 | 248篇 |
2019年 | 303篇 |
2018年 | 298篇 |
2017年 | 254篇 |
2016年 | 274篇 |
2015年 | 274篇 |
2014年 | 387篇 |
2013年 | 444篇 |
2012年 | 691篇 |
2011年 | 620篇 |
2010年 | 364篇 |
2009年 | 352篇 |
2008年 | 540篇 |
2007年 | 485篇 |
2006年 | 490篇 |
2005年 | 469篇 |
2004年 | 406篇 |
2003年 | 370篇 |
2002年 | 333篇 |
2001年 | 82篇 |
2000年 | 60篇 |
1999年 | 70篇 |
1998年 | 74篇 |
1997年 | 56篇 |
1996年 | 41篇 |
1995年 | 41篇 |
1994年 | 29篇 |
1993年 | 23篇 |
1992年 | 29篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 10篇 |
1988年 | 14篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 4篇 |
1907年 | 2篇 |
1906年 | 3篇 |
1905年 | 3篇 |
1904年 | 2篇 |
1903年 | 4篇 |
排序方式: 共有9018条查询结果,搜索用时 7 毫秒
91.
Katja Margelisch MSc Martina Studer PhD Barbara Catherine Ritter PhD Maja Steinlin MD Kurt Leibundgut MD Theda Heinks PhD 《Pediatric blood & cancer》2015,62(10):1805-1812
Background
Survivors of brain tumors have a high risk for a wide range of cognitive problems. These dysfunctions are caused by the lesion itself and its surgical removal, as well as subsequent treatments (chemo‐ and/or radiation therapy). Multiple recent studies have indicated that children with brain tumors (BT) might already exhibit cognitive problems at diagnosis, i.e., before the start of any medical treatment. The aim of the present study was to investigate the baseline neuropsychological profile in children with BT compared to children with an oncological diagnosis not involving the central nervous system (CNS).Methods
Twenty children with BT and 27 children with an oncological disease without involvement of the CNS (age range: 6.1–16.9 years) were evaluated with an extensive battery of neuropsychological tests tailored to the patient's age. Furthermore, the child and his/her parent(s) completed self‐report questionnaires about emotional functioning and quality of life. In both groups, tests were administered before any therapeutic intervention such as surgery, chemotherapy, or irradiation. Groups were comparable with regard to age, gender, and socioeconomic status.Results
Compared to the control group, patients with BTs performed significantly worse in tests of working memory, verbal memory, and attention (effect sizes between 0.28 and 0.47). In contrast, the areas of perceptual reasoning, processing speed, and verbal comprehension were preserved at the time of measurement.Conclusion
Our results highlight the need for cognitive interventions early in the treatment process in order to minimize or prevent academic difficulties as patients return to school. Pediatr Blood Cancer 2015;62:1805–1812. © 2015 The Authors. Pediatric Blood & Cancer, published by Wiley Periodicals, Inc. 相似文献92.
Ionic liquids are largely used to leach metals from primary (ores) and secondary sources (end-of-life products). However, dry ionic liquids with a carboxylic function on the cation have not yet been used to leach metals at temperature above 100 °C and under atmospheric pressure. The ionic liquid betainium bis(trifluoromethylsulfonyl)imide, [Hbet][Tf2N], was used in the dry state to recover neodymium, dysprosium and cobalt from NdFeB magnets and NdFeB production scrap. The magnets and the scrap were crushed, milled and roasted before being leached above 100 °C. Recovery efficiencies below 10% and a lack of selectivity for all the parameters tested pointed to the importance of water in the dissolution process. The influence of the viscosity of the ionic liquid and the composition of the metal oxides after roasting was investigated as well. Although the dissolution of pure metal oxides was faster than the dissolution of the magnets, the low leaching efficiencies could not be attributed to the composition and crystal structure of the samples, since magnets roasted with the same protocol have already been successfully leached in the past, albeit in the presence of water. The role of water on the mass transfer and on the coordination of the metals was studied by viscometry and by spectroscopic methods, respectively. It is shown that for leaching of rare earths with [Hbet][Tf2N], the presence of ligands such as water is mandatory to saturate the first coordination sphere of the dissolved rare-earth ions. This paper provides new insights in the dissolution mechanism of metal oxides by [Hbet][Tf2N] at leaching temperatures higher than those typically used in hydrometallurgical leaching processes.Recovery of neodymium, dysprosium and cobalt from NdFeB magnets with the dry ionic liquid [Hbet][Tf2N] was investigated at 175 °C and atmospheric pressure. 相似文献
93.
Effects on human heart valve immunogenicity in vitro by high concentration cryoprotectant treatment 下载免费PDF全文
Benjamin A. Högerle Maria Schneider Katrin Sudrow Naima Souidi Meaghan Stolk Isabella Werner Anna Biermann Kelvin G.M. Brockbank Ulrich A. Stock Martina Seifert 《Journal of tissue engineering and regenerative medicine》2018,12(2):e1046-e1055
It has been shown previously that cryopreservation, using an ice‐free cryopreservation method with the cryoprotectant formulation VS83, beneficially modulated immune reactions in vivo and in vitro when compared with conventionally frozen tissues. In this study, we assessed the impact of a VS83 post‐treatment of previously conventionally frozen human tissue on responses of human immune cells in vitro. Tissue punches of treated and non‐treated (control) aortic heart valve tissue (leaflets and associated aortic root) were co‐cultured for 7 days with peripheral blood mononuclear cells or enriched CD14+ monocytes. Effects on cellular activation markers, cytokine secretion and immune cell proliferation were analysed by flow cytometry. Flow cytometry studies showed that VS83 treatment of aortic root tissue promoted activation and differentiation of CD14+ monocytes, inducing both up‐regulation of CD16 and down‐regulation of CD14. Significantly enhanced expression levels for the C‐C chemokine receptor (CCR)7 and the human leukocyte antigen (HLA)‐DR on monocytes co‐cultured with VS83‐treated aortic root tissue were measured, while the interleukin (IL)‐6 and monocyte chemoattractant protein (MCP)‐1 release was suppressed. However, the levels of interferon (IFN)γ and tumour necrosis factor (TNF)α remained undetectable, indicating that complete activation into pro‐inflammatory macrophages did not occur. Similar, but non‐significant, changes occurred with VS83‐treated leaflets. Additionally, in co‐cultures with T cells, proliferation and cytokine secretion responses were minimal. In conclusion, post‐treatment of conventionally cryopreserved human heart valve tissue with the VS83 formulation induces changes in the activation and differentiation characteristics of human monocytes, and thereby may influence long‐term performance following implantation. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
94.
Quantity,quality, and functionality of peripheral blood cells derived from residual blood of different apheresis kits 下载免费PDF全文
95.
96.
Alessandra Elvevi Elena Maria Elli Martina Luc Miki Scaravaglio Fabio Pagni Stefano Ceola Laura Ratti Pietro Invernizzi Sara Massironi 《World journal of gastroenterology : WJG》2022,28(29):3767-3779
Mastocytosis is a rare and heterogeneous disease characterized by various clinical and biological features that affect different prognoses and treatments. The disease is usually divided into 2 principal categories: cutaneous and systemic disease (SM). Clinical features can be related to mast cell (MC) mediator release or pathological MC infiltration. SM is a disease often hard to identify, and the diagnosis is based on clinical, biological, histological, and molecular criteria with different specialists involved in the patient’s clinical work-up. Among all manifestations of the disease, gastrointestinal (GI) symptoms are common, being present in 14%-85% of patients, and can significantly impair the quality of life. Here we review the data regarding GI involvement in SM, in terms of clinical presentations, histological and endoscopic features, the pathogenesis of GI symptoms, and their treatment. 相似文献
97.
Roberta Angelico Bruno Sensi Tommaso M Manzia Giuseppe Tisone Giuseppe Grassi Alessandro Signorello Martina Milana Ilaria Lenci Leonardo Baiocchi 《World journal of gastroenterology : WJG》2021,27(45):7771-7783
Chronic rejection (CR) of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation. Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy, CR still represents an important cause of graft injury, which might be irreversible, leading to graft loss requiring re-transplantation. To date, we still do not fully appreciate the mechanisms underlying this process. In addition to T cell-mediated CR, which was initially the only recognized type of CR, recently a new form of liver allograft CR, antibody-mediated CR, has been identified. This has indeed opened an era of thriving research and renewed interest in the field. Liver biopsy is needed for a definitive diagnosis of CR, but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation. Moreover, the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury, which should not be disregarded. Therapies for CR may only be effective in the “early” phases, and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage. Herein, we provide an overview of the current knowledge and research on CR, focusing on early detection, identification of non-invasive biomarkers, immuno suppressive management, re-transplantation and future perspectives of CR. 相似文献
98.
99.