全文获取类型
收费全文 | 10225篇 |
免费 | 987篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 105篇 |
儿科学 | 377篇 |
妇产科学 | 256篇 |
基础医学 | 1624篇 |
口腔科学 | 230篇 |
临床医学 | 931篇 |
内科学 | 2364篇 |
皮肤病学 | 159篇 |
神经病学 | 1031篇 |
特种医学 | 261篇 |
外科学 | 1041篇 |
综合类 | 125篇 |
一般理论 | 9篇 |
预防医学 | 1144篇 |
眼科学 | 216篇 |
药学 | 686篇 |
中国医学 | 15篇 |
肿瘤学 | 672篇 |
出版年
2023年 | 97篇 |
2022年 | 182篇 |
2021年 | 336篇 |
2020年 | 177篇 |
2019年 | 281篇 |
2018年 | 292篇 |
2017年 | 197篇 |
2016年 | 226篇 |
2015年 | 305篇 |
2014年 | 336篇 |
2013年 | 431篇 |
2012年 | 716篇 |
2011年 | 680篇 |
2010年 | 391篇 |
2009年 | 297篇 |
2008年 | 554篇 |
2007年 | 457篇 |
2006年 | 503篇 |
2005年 | 514篇 |
2004年 | 417篇 |
2003年 | 368篇 |
2002年 | 316篇 |
2001年 | 129篇 |
2000年 | 117篇 |
1999年 | 125篇 |
1998年 | 75篇 |
1996年 | 68篇 |
1994年 | 58篇 |
1993年 | 57篇 |
1992年 | 115篇 |
1991年 | 107篇 |
1990年 | 128篇 |
1989年 | 130篇 |
1988年 | 126篇 |
1987年 | 141篇 |
1986年 | 133篇 |
1985年 | 128篇 |
1984年 | 126篇 |
1983年 | 139篇 |
1982年 | 95篇 |
1981年 | 86篇 |
1980年 | 87篇 |
1979年 | 115篇 |
1978年 | 92篇 |
1977年 | 79篇 |
1976年 | 54篇 |
1975年 | 56篇 |
1974年 | 53篇 |
1971年 | 53篇 |
1970年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Rosario Gulias-Cañizo Anell Lagunes-Guillén Arturo González-Robles Erika Sánchez-Guzmán Federico Castro-Muñozledo 《Burns : journal of the International Society for Burn Injuries》2019,45(2):398-412
Background
Since recent reports have shown that (-)-Epigallocatechin-3-gallate (EGCG) could be used for treating proliferative and inflammatory disorders, we explored its use for the management of corneal chemical burns.Materials and methods
Initially, EGCG was assayed on the rabbit corneal epithelial cell line RCE1(5T5) to establish the best testing conditions, and to avoid unwanted outcomes in the experimental animals. Then, we studied its effects on cell proliferation, cell cycle progression and cell differentiation. Afterwards, we instilled EGCG in experimental grade II corneal alkali burns in mice, three times a day up to 21 days, and evaluated by slit lamp examination and histological sections of corneal epithelial, corneal endothelial and stromal edema, as well as the presence of inflammatory cells and neovascularization.Results
EGCG reduced cell growth and led to a decline in the proportion of proliferative cells in a concentration dependent manner. At 10 μM, EGCG promoted cell differentiation, an effect not related with apoptosis or cytotoxicity. When 10 μM EGCG was instilled in corneal alkali burns in mice three times a day up to 21 days, EGCG significantly reduced corneal opacity and neovascularization. The improved clinical appearance of the cornea was associated to a controlled epithelial growth; epithelial morphology was similar to that observed in normal epithelium and contrasted with the hyperproliferative, desquamating epithelium observed in control burn wounds. EGCG reduced corneal, stromal and endothelial edema, and wound inflammation.Conclusion
This work constitutes the first evidence for the use of EGCG in the acute phase of a corneal alkali burn, representing a possible novel alternative to improve patient outcomes as an add-on therapy. 相似文献3.
4.
Carlos A. ávila-Orta Zoe V. Qui?ones-Jurado Miguel A. Waldo-Mendoza Erika A. Rivera-Paz Víctor J. Cruz-Delgado José M. Mata-Padilla Pablo González-Morones Ronald F. Ziolo 《Materials》2015,8(11):7900-7912
Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods. 相似文献
5.
Hepatitis C virus (HCV) infection is a major health care issue in liver and kidney transplantation. Besides negatively affecting both patient and graft survival, HCV is associated with a heightened risk for new onset diabetes mellitus (NODM). The mechanisms underlying the diabetogenicity of HCV are complex but are likely to involve insulin resistance caused by inhibitory actions of the virus on insulin regulatory pathways in the liver. The resultant glucose dysregulation is an important determinant of increased morbidity and mortality in liver and kidney recipients. This review highlights the concerns for outcomes in HCV-positive liver and kidney transplant patients with particular focus on the interrelationship between hepatitis C and diabetes. Data about the potential role of calcineurin inhibitors, corticosteroids and mycophenolate mofetil in HCV infection and HCV-associated NODM will also be discussed. 相似文献
6.
R W Hertle A B Leahey S Bloom D B Schaffer S Bartlett 《Ophthalmic plastic and reconstructive surgery》1990,6(4):278-282
Chorioretinal folds have been reported as a result of many intraocular and extraocular inflammatory processes or tumors. Visual loss is usually secondary to a combination of the underlying process and chorioretinal folds involving the macula. We report a patient who developed decreased vision, metamorphopsia, chorioretinal folds, and a lamellar macular hole secondary to global compression by a bone fragment. The chorioretinal folds regressed and his vision stabilized following surgical decompression. Chorioretinal folds and lamellar macular hold formation are previously unrecognized complications of reconstructive craniofacial surgery. 相似文献
7.
8.
Isabella Sch?ll George Boltz-Nitulescu Erika Jensen-Jarolim 《Journal of controlled release》2005,104(1):1-27
For the treatment of infectious diseases, cancer and allergy, the directed induction of an appropriate immune response is the ultimate goal. Therefore, with the development of pure, often very small proteins, peptides or DNA by molecular biology techniques, the research for suitable adjuvants or delivery systems became increasingly important. Particle formulations are made of a variety of materials, including lipids, proteins or amino acids, polysaccharides, polyacrylic substances or organic acids. Microparticles serve as vehicles and provide a depot for the entrapped or coupled antigen. The release occurs in a pulsatile or continuous manner, a feature, which is well controllable for many particulate systems. Particles attract antigen presenting cells to the administration site, thereby guaranteeing the efficient presentation of the antigen to the immune system. Importantly, particles also protect the entrapped substance. This is especially necessary after oral application to avoid gastric or tryptic breakdown. In this article, the design and construction of different antigen delivery systems and their immune effects, with special focus on the suitability for allergy treatment, are discussed. 相似文献
9.
D J Brooks J S Gibbs P Sharp S Herold D R Turton S K Luthra E M Kohner S R Bloom T Jones 《Journal of cerebral blood flow and metabolism》1986,6(2):240-244
Regional cerebral [11C]3-O-methyl-D-glucose ([11C]MeG) uptake kinetics have been measured in five insulin-dependent diabetic patients and four normal controls using positron emission tomography (PET). Concomitant measurement of regional cerebral blood volume and CBF enabled corrections for the presence of intravascular [11C]MeG signal in cerebral regions of interest to be carried out, and regional cerebral [11C]MeG unidirectional extraction fractions to be computed. Four of the five diabetic subjects were studied with their fasting plasma glucose level clamped at a normoglycaemic level (4 mM), and four were studied at hyperglycaemic plasma glucose levels (mean 13 mM). The four diabetic subjects whose fasting plasma glucose levels were clamped at a normoglycaemic level of 4 mM had mean fasting whole-brain, cortical, and white matter [11C]MeG extraction fractions of 15, 15, and 16%, respectively, values similar to those found for the four normal controls (whole brain, 14%; cortex, 13%; white matter, 17%). Mean regional cerebral [11C]MeG extraction fractions were significantly reduced in diabetic subjects during hyperglycaemia whether their plasma insulin levels were undetectable or whether they were raised by continuous intravenous insulin infusion. Such a reduction in [11C]MeG extraction under hyperglycaemic conditions can be explained entirely in terms of increased competition between [11C]MeG and D-glucose for the passive facilitated transport carrier system for hexoses across the blood-brain barrier (BBB). It is concluded that the number and affinity of D-glucose carriers present in the BBB are within normal limits in treated insulin-dependent diabetic subjects. In addition, insulin appears to have no effect on the transport of D-glucose across the BBB. 相似文献
10.