全文获取类型
收费全文 | 4497篇 |
免费 | 522篇 |
国内免费 | 90篇 |
出版年
2024年 | 13篇 |
2023年 | 151篇 |
2022年 | 181篇 |
2021年 | 365篇 |
2020年 | 322篇 |
2019年 | 291篇 |
2018年 | 297篇 |
2017年 | 204篇 |
2016年 | 200篇 |
2015年 | 226篇 |
2014年 | 389篇 |
2013年 | 408篇 |
2012年 | 260篇 |
2011年 | 260篇 |
2010年 | 135篇 |
2009年 | 186篇 |
2008年 | 197篇 |
2007年 | 159篇 |
2006年 | 153篇 |
2005年 | 131篇 |
2004年 | 82篇 |
2003年 | 94篇 |
2002年 | 67篇 |
2001年 | 57篇 |
2000年 | 29篇 |
1999年 | 41篇 |
1998年 | 30篇 |
1997年 | 28篇 |
1996年 | 24篇 |
1995年 | 19篇 |
1994年 | 31篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有5109条查询结果,搜索用时 140 毫秒
81.
82.
《Biotechnic & histochemistry》2013,88(8):428-439
AbstractWe investigated the presence and alteration of lymphatic vessels in joints of arthritic mice using a whole-slide imaging system. Joints and long bone sections were cut from paraffin blocks of two mouse models of arthritis: meniscal-ligamentous injury (MLI)-induced osteoarthritis (OA) and TNF transgene (TNF-Tg)-induced rheumatoid arthritis (RA). MLI-OA mice were fed a high fat diet to accelerate OA development. TNF-Tg mice were treated with lymphatic growth factor VEGF-C virus to stimulate lymphangiogenesis. Sections were double immunofluorescence stained with anti-podoplanin and alpha-smooth muscle actin antibodies. The area and number of lymphatic capillaries and mature lymphatic vessels were determined using a whole-slide imaging system and its associated software. Lymphatic vessels in joints were distributed in soft tissues mainly around the joint capsule, ligaments, fat pads and muscles. In long bones, enriched lymphatic vessels were present in the periosteal areas adjacent to the blood vessels. Occasionally, lymphatic vessels were observed in the cortical bone. Increased lymphatic capillaries, but decreased mature lymphatic vessels, were detected in both OA and RA joints. VEGF-C treatment increased lymphatic capillary and mature vessel formation in RA joints. Our findings suggest that the lymphatic system may play an important role in arthritis pathogenesis and treatment. 相似文献
83.
《Biotechnic & histochemistry》2013,88(2):111-123
AbstractWe used a rat model to decellularize and seed alveolar cells on a three-dimensional lung scaffold to preserve alveolar microarchitecture. We verified the preservation of terminal respiratory structure by casting and by scanning electron microscopy (SEM) of the casts after decellularization. Whole lungs were obtained from 12 healthy Sprague-Dawley rats, cannulated through the trachea under sterile conditions, and decellularized using a detergent-based method. Casting of both natural and decellularized lungs was performed to verify preservation of the inner microstructure of scaffolds for further cell seeding. Alveolar cell seeding was performed using green fluorescent protein (GFP) lung cells and non-GFP lung cells, and a peristaltic pump. We assessed cell seeding using histological and immunohistochemical staining, and enzymatic evaluation. All cellular components were removed completely from the scaffolds, and histological staining and SEM of casts were used to verify the preservation of tissue structure. Tensile tests verified conservation of biomechanical properties. The hydroxyproline content of decellularized lungs was similar to native lung. Histological and immunohistochemical evaluations showed effective cell seeding on decellularized matrices. Enzymatic measurement of trypsin and alpha 1 antitrypsin suggested the potential functional properties of the regenerated lungs. Casts produced by our method have satisfactory geometrical properties for further cell seeding of lung scaffolds. Preservation of micro-architecture and terminal alveoli that was confirmed by SEM of lung casts increases the probability of an effective cell seeding process. 相似文献
84.
85.
S. Loerakker D. L. Bader F. P.T. Baaijens C. W.J. Oomens 《Computer methods in biomechanics and biomedical engineering》2013,16(3):338-345
Deep tissue injury (DTI) is a severe form of pressure ulcer where tissue damage starts in deep tissues underneath intact skin. Tissue deformation may play an important role in the aetiology, which can be investigated using an experimental–numerical approach. Recently, an animal-specific finite element model has been developed to simulate experiments in which muscle tissue was compressed with an indenter. In this study, the material behaviour and boundary conditions were adapted to improve the agreement between model and experiment and to investigate the influence of these adaptations on the predicted strain distribution. The use of a highly nonlinear material law and including friction between the indenter and the muscle both improved the quality of the model and considerably influenced the estimated strain distribution. With the improved model, the required sample size to detect significant differences between loading conditions can be diminished, which is clearly relevant in experiments involving animals. 相似文献
86.
S. Loerakker L.R. Solis D.L. Bader F.P.T. Baaijens V.K. Mushahwar C.W.J. Oomens 《Computer methods in biomechanics and biomedical engineering》2013,16(5):520-529
Mechanical loading of soft tissues covering bony prominences can cause skeletal muscle damage, ultimately resulting in a severe pressure ulcer termed deep tissue injury (DTI). Deformation plays an important role in the aetiology of DTI. Therefore, it is essential to minimise internal muscle deformations in subjects at risk of DTI. As an example, spinal cord-injured (SCI) individuals exhibit structural changes leading to a decrease in muscle thickness and stiffness, which subsequently increase the tissue deformations. In the present study, an animal-specific finite element model, where the geometry and boundary conditions were derived from magnetic resonance images, was developed. It was used to investigate the internal deformations in the muscle, fat and skin layers of the porcine buttocks during loading. The model indicated the presence of large deformations in both the muscle and the fat layers, with maximum shear strains up to 0.65 in muscle tissue and 0.63 in fat. Furthermore, a sensitivity analysis showed that the tissue deformations depend considerably on the relative stiffness values of the different tissues. For example, a change in muscle stiffness had a large effect on the muscle deformations. A 50% decrease in stiffness caused an increase in maximum shear strain from 0.65 to 0.99, whereas a 50% increase in stiffness resulted in a decrease in maximum shear strain from 0.65 to 0.49. These results indicate the importance of restoring tissue properties after SCI, with the use of, for example, electrical stimulation, to prevent the development of DTI. 相似文献
87.
Joshua E. Johnson 《Computer methods in biomechanics and biomedical engineering》2013,16(16):1856-1861
Measurement of static alignment of articulating joints is of clinical benefit and can be determined using image-based registration. We propose a method that could potentially improve the outcome of image-based registration by using initial manual registration. Magnetic resonance images of two wrist specimens were acquired in the relaxed position and during simulated grasp. Transformations were determined from voxel-based image registration between the two volumes. The volumes were manually aligned to match as closely as possible before auto-registration, from which standard transformations were obtained. Then, translation/rotation perturbations were applied to the manual registration to obtain altered initial positions, from which altered auto-registration transformations were obtained. Models of the radiolunate joint were also constructed from the images to simulate joint contact mechanics. We compared the sensitivity of transformations (translations and rotations) and contact mechanics to altering the initial registration condition from the defined standard. We observed that with increasing perturbation, transformation errors appeared to increase and values for contact force and contact area appeared to decrease. Based on these preliminary findings, it appears that the final registration outcome is sensitive to the initial registration. 相似文献
88.
89.
《Free radical research》2013,47(4):374-382
AbstractMitochondrial reactive oxygen species (ROS) is a key element in the regulation of several physiological functions and in the development or progression of multiple pathological events. A key task in the study of mitochondrial ROS is to establish reliable methods for measuring the ROS level in mitochondria with high selectivity, sensitivity, and spatiotemporal resolution. Over the last decade, imaging tools with fluorescent indicators from either small-molecule dyes or genetically encoded probes that can be targeted to mitochondria have been developed, which provide a powerful method to visualize and even quantify mitochondrial ROS level not only in live cells, but also in live animals. These innovative tools that have bestowed exciting new insights in mitochondrial ROS biology have been further promoted with the invention of new techniques in indicator design and fluorescent detection. However, these probes present some limitations in terms of specificity, sensitivity, and kinetics; failure to recognize these limitations often results in inappropriate interpretations of data. This review evaluates the recent advances in mitochondrial ROS imaging approaches with emphasis on their proper application and limitations, and highlights the future perspectives in the development of novel fluorescent probes for visualizing all species of ROS. 相似文献
90.