全文获取类型
收费全文 | 38975篇 |
免费 | 1958篇 |
国内免费 | 141篇 |
专业分类
耳鼻咽喉 | 572篇 |
儿科学 | 979篇 |
妇产科学 | 827篇 |
基础医学 | 5132篇 |
口腔科学 | 2787篇 |
临床医学 | 2482篇 |
内科学 | 9041篇 |
皮肤病学 | 1115篇 |
神经病学 | 3569篇 |
特种医学 | 908篇 |
外国民族医学 | 1篇 |
外科学 | 4546篇 |
综合类 | 217篇 |
一般理论 | 7篇 |
预防医学 | 3521篇 |
眼科学 | 908篇 |
药学 | 2870篇 |
1篇 | |
中国医学 | 278篇 |
肿瘤学 | 1313篇 |
出版年
2024年 | 72篇 |
2023年 | 323篇 |
2022年 | 717篇 |
2021年 | 1408篇 |
2020年 | 771篇 |
2019年 | 1182篇 |
2018年 | 1495篇 |
2017年 | 948篇 |
2016年 | 1028篇 |
2015年 | 1172篇 |
2014年 | 1576篇 |
2013年 | 1988篇 |
2012年 | 3032篇 |
2011年 | 3248篇 |
2010年 | 1735篇 |
2009年 | 1355篇 |
2008年 | 2391篇 |
2007年 | 2301篇 |
2006年 | 2085篇 |
2005年 | 1876篇 |
2004年 | 1757篇 |
2003年 | 1430篇 |
2002年 | 1346篇 |
2001年 | 851篇 |
2000年 | 870篇 |
1999年 | 683篇 |
1998年 | 232篇 |
1997年 | 156篇 |
1996年 | 160篇 |
1995年 | 122篇 |
1994年 | 130篇 |
1993年 | 90篇 |
1992年 | 250篇 |
1991年 | 250篇 |
1990年 | 221篇 |
1989年 | 174篇 |
1988年 | 186篇 |
1987年 | 164篇 |
1986年 | 132篇 |
1985年 | 129篇 |
1984年 | 103篇 |
1983年 | 99篇 |
1981年 | 46篇 |
1980年 | 43篇 |
1979年 | 77篇 |
1978年 | 58篇 |
1975年 | 44篇 |
1972年 | 40篇 |
1971年 | 51篇 |
1967年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
991.
In host organisms with normal micronutrient status, nutritional immunity is a strongly regulated response aiming at decreasing the progression and severity of infections. Zinc deficiency may disturb this balance, impairing immune responses to infections, which may indirectly increase infection-related anemia. Since zinc deficiency may associate directly with anemia, the role of infections is often overlooked. Herein, we investigated the participation of infections (or inflammation) in the causal pathway between zinc deficiency and anemia. This transversal study, conducted in 2015 in Bengo-Angola, enrolled 852 under-3-year-old children. Logistic regression models were used to investigate interaction and mediation effects, and significance was confirmed by the Sobel test. In sum, 6.8% of children had zinc deficiency, 45.9% had anemia, and 15.6% had at least one intestinal/urogenital parasite. Furthermore, we found (1) no evidence that inflammation mediates or interacts with zinc deficiency to cause anemia, and (2) zinc deficiency interacts with infections, significantly increasing the odds of anemia (OR: 13.26, p = 0.022). This interaction was stronger among children with iron deficiency anemia (OR: 46.66, p = 0.003). Our results suggest that zinc deficiency may impair the immune response to infections and/or that intestinal parasites could have developed mechanisms to avoid zinc-limited environments. Further studies are needed to corroborate these suggestions. 相似文献
992.
Design and characterization of a biodegradable double‐layer scaffold aimed at periodontal tissue‐engineering applications 下载免费PDF全文
João F. Requicha Carlos A. Viegas Shantesh Hede Isabel B. Leonor Rui L. Reis Manuela E. Gomes 《Journal of tissue engineering and regenerative medicine》2016,10(5):392-403
The inefficacy of the currently used therapies in achieving the regeneration ad integrum of the periodontium stimulates the search for alternative approaches, such as tissue‐engineering strategies. Therefore, the core objective of this study was to develop a biodegradable double‐layer scaffold for periodontal tissue engineering. The design philosophy was based on a double‐layered construct obtained from a blend of starch and poly‐ε‐caprolactone (30:70 wt%; SPCL). A SPCL fibre mesh functionalized with silanol groups to promote osteogenesis was combined with a SPCL solvent casting membrane aiming at acting as a barrier against the migration of gingival epithelium into the periodontal defect. Each layer of the double‐layer scaffolds was characterized in terms of morphology, surface chemical composition, degradation behaviour and mechanical properties. Moreover, the behaviour of seeded/cultured canine adipose‐derived stem cells (cASCs) was assessed. In general, the developed double‐layered scaffolds demonstrated adequate degradation and mechanical behaviour for the target application. Furthermore, the biological assays revealed that both layers of the scaffold allow adhesion and proliferation of the seeded undifferentiated cASCs, and the incorporation of silanol groups into the fibre‐mesh layer enhance the expression of a typical osteogenic marker. This study allowed an innovative construct to be developed, combining a three‐dimensional (3D) scaffold with osteoconductive properties and with potential to assist periodontal regeneration, carrying new possible solutions to current clinical needs. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
993.
994.
Zekanowski C Religa D Safranow K Maruszak A Dziedziejko V Styczyńska M Gacia M Golan M Pepłońska B Chlubek D Kuźnicki J Barcikowska M 《Journal of neural transmission (Vienna, Austria : 1996)》2005,112(6):839-845
Summary. The –22c/t polymorphism in the promoter of the presenilin 1 gene is associated with increased risk for Alzheimers disease (AD) in some populations. It was shown that –22c allele is connected with two-fold decrease in promoter activity. We studied the impact of the polymorphism in groups of Polish late-onset and early-onset AD patients. Our results suggest that –22c/t polymorphism is not connected with AD in Polish population. The –22t allele showed a high degree of linkage disequilibrium with –2797 insertion of 13bp. An additional –2923g/t polymorphism is also not connected with –22c/t and is not a risk factor for AD. 相似文献
995.
Gemma Rojo-Martínez Sergio Valdés Natalia Colomo M. Isabel Lucena Sonia Gaztambide Ramón Gomis Roser Casamitjana Rafael Carmena Miguel Catalá María T. Martínez-Larrad Manuel Serrano-Ríos Luis Castaño Joan Vendrell Juan Girbés Josep Franch José A. Vázquez Inmaculada Mora-Peces Inés Urrutia Gemma Pascual-Manich Emilio Ortega Edelmiro Menéndez Elias Delgado Elena Bordiú Conxa Castell Alfonso López-Alba Alberto Goday Alfonso Calle Anna Bosch-Comas Federico Soriguer 《Revista espa?ola de cardiología》2013
996.
997.
998.
de Paula Reis Michelle de Lima Daniely Alves Pauli Karoline Bach Andreotti Carlos Eduardo Linhares de Moraes André Luiz Soares Gonçalves Daniela Dib Navarro Italmar Teodorico Bueno Paulo Sérgio Alves Seixas Flavio Augusto Vicente Gasparotto Junior Arquimedes Lourenço Emerson Luiz Botelho 《Parasitology research》2018,117(5):1465-1471
Parasitology Research - Toxoplasmosis is a zoonosis of worldwide distribution. Currently, two drugs, pyrimethamine and sulfadiazine, are used as a reference in the treatment of toxoplasmosis, but... 相似文献
999.
In vivo performance of a sol-gel glass-coated collagen 总被引:1,自引:0,他引:1
Andrade AL Andrade SP Domingues RZ 《Journal of biomedical materials research. Part B, Applied biomaterials》2006,79(1):122-128
Synthetic bioactive materials offer possibilities to repair large tissue defects. It is well known that bioactivity, angiogenesis, and inflammation are key events in implant incorporation. Using glass-coated and glass-free collagen as potential bone graft substitutes, we carried out in vitro bioactivity and an in vivo angiogenesis and inflammation studies. The in vitro study showed bioactivity when the glass-coated samples were left in SBF for 5 days. This was confirmed by FTIR results, which presented P--O vibration bands characteristic of hydroxyapatite close to 1060 cm(-1) and 600 cm(-1). The in vivo response was evaluated following subcutaneous implantation of the biomaterial in the mouse dorsa. Angiogenesis, as determined by hemoglobin content extracted from implants 7 and 14 days after implantation, increased progressively in both glass-coated and glass-free collagen implants. However, vascularization was higher in the glass-coated collagen implants 14 days after implantation (mug Hb per mg wet tissue 6.0 +/- 0.3) compared with the glass-free group (1.6 +/- 0.1). The inflammatory process, determined by the levels of myeloperoxidase and N-acetylglucosaminidase, was similar for both implants. This study shows that glass-coated collagen implants hold osteogenic and angiogenic potential and may be used in clinical conditions requiring improvement of these biological processes. 相似文献
1000.
Mario De Menezes Coppola Fabricio Rochedo Concei o Carlos Gil-Turnes 《Food and Agricultural Immunology》2005,16(3):213-219
The effect of Saccharomyces boulardii and Bacillus cereus var. toyoi on the humoral and cellular response of mice to the simultaneous inoculation of a tetravalent E. coli bacterin and a viable vaccine against Canine Parvovirus is reported. Thirty-six isogenic BALB-c female mice, seven weeks old, were vaccinated with 1/20th of the dose used for pigs and dogs, respectively, and randomly divided into three groups. Group 1 received non-supplemented feed, group 2 was supplemented with S. boulardii, and group 3 with Bacillus cereus var. toyoi. The humoral response was quantified through ELISAs using specific antigens, and the cellular response quantifying IL-4 and IFNg through ELISA. Means of seroconversions to the bacterin were always higher in supplemented mice than in controls, varying from 1.6-1.8 for group 2 and from 1.2-1.4 for group 3. Seroconversions against Parvovirus for group 2 were 5.2-12 times higher, and those of group 3 were 6.8-9.1 times higher than those of controls. IL-4 was produced by spleen cells of S. boulardii supplemented mice stimulated with E. coli fimbriae. 相似文献