全文获取类型
收费全文 | 237篇 |
免费 | 53篇 |
国内免费 | 1篇 |
专业分类
291篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 21篇 |
2020年 | 9篇 |
2019年 | 21篇 |
2018年 | 10篇 |
2017年 | 20篇 |
2016年 | 16篇 |
2015年 | 16篇 |
2014年 | 20篇 |
2013年 | 26篇 |
2012年 | 13篇 |
2011年 | 11篇 |
2010年 | 2篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 7篇 |
2006年 | 13篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 11篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有291条查询结果,搜索用时 15 毫秒
121.
目的:对比微血管减压(MVD)和经皮穿刺球囊压迫(PBC)治疗原发性三叉神经痛(PTN)的疗效。方法:选择2010年5月至2013年11月在我院接受治疗的PTN患者124例进行研究,根据数字法随机分成MVD组及PBC组各62例,两组分别行对应手术,随访18个月,对比两组手术相关指标、疗效以及术后并发症。结果:MVD组的手术时间与术中出血量,以及住院时间和住院费用均分别大于PBC组(均P0.05)。MVD组治疗后完全无痛的比例显著高于PBC组,轻度复发的比例显著低于PBC组(均P0.05)。MVD组的麻木及总并发症发生率均分别显著低于PBC组(均P0.05)。结论:MVD术式与PBC术式在治疗PTN时均具有较好的疗效,MVD术后无痛和并发症情况较好,而PBC创伤较小,较适合高龄体弱而无法耐受较大手术者,临床治疗时应合理地选用相关术式。 相似文献
122.
123.
124.
Alexandre Dewulf Thibaut De Meulemeester Manuel Dehon Michael S. Engel Denis Michez 《ZooKeys》2014,(389):35-48
Although bees are one of the major lineages of pollinators and are today quite diverse, few well-preserved fossils are available from which to establish the tempo of their diversification/extinction since the Early Cretaceous. Here we present a reassessment of the taxonomic affinities of Melitta willardi
Cockerell 1909, preserved as a compression fossil from the Florissant shales of Colorado, USA. Based on geometric morphometric wing shape analyses M. willardi cannot be confidently assigned to the genus Melitta Kirby (Anthophila, Melittidae). Instead, the species exhibits phenotypic affinity with the subfamily Andreninae (Anthophila, Andrenidae), but does not appear to belong to any of the known genera therein. Accordingly, we describe a new genus, Andrenopteryx
gen. n., based on wing shape as well as additional morphological features and to accommodate M. willardi. The new combination Andrenopteryx willardi (Cockerell) is established. 相似文献
125.
Anti-inflammatory effects of IL-4 and dynamic compression in IL-1beta stimulated chondrocytes 总被引:1,自引:0,他引:1
Chowdhury TT Bader DL Lee DA 《Biochemical and biophysical research communications》2006,339(1):241-247
Mechanical loading can counteract inflammatory pathways induced by IL-1beta by inhibiting *NO and PGE2, catabolic mediators known to be involved in cartilage degradation. The current study investigates the potential of dynamic compression, in combination with the anti-inflammatory cytokine, IL-4, to further abrogate the IL-1beta induced effects. The data presented demonstrate that IL-4 alone can inhibit nitrite release in the presence and absence of IL-1beta and partially reverse the IL-1beta induced PGE2 release. When provided in combination, IL-4 and dynamic compression could further abrogate the IL-1beta induced nitrite and PGE2 release. IL-1beta inhibited [3H]thymidine incorporation and this effect could be reversed by IL-4 or dynamic strain alone or both in combination. By contrast, 35SO4 incorporation was not influenced by IL-4 and/or dynamic strain in IL-1beta stimulated constructs. IL-4 and mechanical loading may therefore provide a potential protective mechanism for cartilage destruction as observed in OA. 相似文献
126.
Perioli L Ambrogi V Giovagnoli S Blasi P Mancini A Ricci M Rossi C 《AAPS PharmSciTech》2008,9(1):274-281
The purpose of this research was to study the compression force influence on polymers, tablet behavior and drug release rate.
Several tablet batches were produced by varying the compression force and by using hydroxyethyl cellulose (HEC) and Carbopol
940 in the 1:1 ratio as matrix forming polymers. All batches were characterized by DSC and X-ray analyses and in terms of
swelling, ex vivo and in vivo mucoadhesive time, ex vivo mucoadhesion force, and in vitro and in vivo release. No significant excipient–excipient or excipient–drug interactions were observed in any of the batches. All the tablets
hydrated quickly and their high hydration percentage showed that the compression forces used did not remarkably affect the
water penetration and the polymeric chain stretching. Mucoadhesion performances and drug release were mainly influenced by
compression force; its increase produced higher ex vivo and in vivo mucoadhesion and the in vitro and in vivo drug releases were seen to decrease with the increase of the compression force. However tablets fabricated by using the lowest
compression force showed the best in vivo mucoadhesive time and hydrated faster when compared to the others. Tablets 4 and 5, prepared with the highest forces, caused
pain during in vivo application and gave rise to irritation needing to be detached by the volunteers while tablet 1, prepared with the lowest
force, gave the best results because it was able to produce the highest drug salivary concentration and no pain. All tablets
exhibited an anomalous release mechanism. 相似文献
127.
Post-operative changes in trabecular bone morphology at the cement-bone interface can vary depending on time in service. This study aims to investigate how micromotion and bone strains change at the tibial bone-cement interface before and after cementation. This work discusses whether the morphology of the post-mortem interface can be explained by studying changes in these mechanical quantities. Three post-mortem cement-bone interface specimens showing varying levels of bone resorption (minimal, extensive and intermediate) were selected for this study Using image segmentation techniques, masks of the post-mortem bone were dilated to fill up the mould spaces in the cement to obtain the immediately post-operative situation. Finite element (FE) models of the post-mortem and post-operative situation were created from these segmentation masks. Subsequent removal of the cement layer resulted in the pre-operative situation. FE micromotion and bone strains were analyzed for the interdigitated trabecular bone. For all specimens micromotion increased from the post-operative to the post-mortem models (distally, in specimen 1: 0.1 to 0.5 µm; specimen 2: 0.2 to 0.8 µm; specimen 3: 0.27 to 1.62 µm). Similarly bone strains were shown to increase from post-operative to post-mortem (distally, in specimen 1: −185 to −389 µε; specimen 2: −170 to −824 µε; specimen 3: −216 to −1024 µε). Post-mortem interdigitated bone was found to be strain shielded in comparison with supporting bone indicating that failure of bone would occur distal to the interface. These results indicate that stress shielding of interdigitated trabeculae is a plausible explanation for resorption patterns observed in post-mortem specimens. 相似文献
128.
129.
Cécile Conte Catherine Masson Pierre-Jean Arnoux 《Computer methods in biomechanics and biomedical engineering》2013,16(9):993-999
To prevent traumas to abdominal organs, the selection of efficient safety devices should be based on a detailed knowledge of injury mechanisms and related injury criteria. In this sense, finite element (FE) simulation coupled with experiment could be a valuable tool to provide a better understanding of the behaviour of internal organs under crash conditions. This work proposes a methodology based on inverse analysis which combines exploration process optimisation and robustness study to obtain mechanical behaviour of the complex structure of the liver through FE simulation. The liver characterisation was based on Mooney–Rivlin hyperelastic behaviour law considering whole liver structure under uniform quasi-static compression. With the global method used, the model fits experimental data. The variability induced by modelling parameters is quantified within a reasonable time. 相似文献
130.
《Animal : an international journal of animal bioscience》2021,15(5):100201
Calcium (Ca) and non-phytate phosphorus (NPP) are fundamental minerals for bone formation and growth, and optimizing their level is required in broiler production. This experiment was conducted to investigate the effect and interaction of dietary Ca and NPP on growth performance, tibial characteristics and biochemical variables for slow-growing yellow-feathered broilers during 1–28 d (the starter phase). Seven hundred and twenty hatchling female broilers were randomly divided into nine groups, which received three levels of Ca (0.80%, 0.90%, 1.00%) each with three levels of NPP (0.40%, 0.45%, 0.50%). The results showed: (1) Dietary Ca level influenced (P < 0.05) the feed to gain ratio (F:G) and average daily feed intake (ADFI). Compared with broilers provided 1.00% Ca, ADFI of birds provided with 0.80% or 0.90% Ca and F:G of those with 0.90% Ca were decreased (P < 0.05). Dietary NPP level did not affect (P > 0.05) growth performance of broilers. (2) Dietary Ca affected (P < 0.05) tibial length. Compared with birds provided with 0.80% Ca, the length of tibia was decreased (P < 0.05) in birds received 1.00% Ca. Interactions between dietary Ca and NPP were observed (P < 0.05) on ash content, breaking strength and bone density of tibia. These three characteristics were better when birds received 0.90% Ca and 0.40% NPP or 1.00% Ca and 0.45% NPP. (3) Dietary Ca significantly affected (P < 0.05) the activity of alkaline phosphatase (ALP) in serum with decreased activity in birds fed 0.80% or 0.90% Ca. The dietary NPP influenced (P < 0.05) the contents of Ca in serum. Serum Ca was increased when birds were provided 0.40% NPP compared with other levels (P < 0.05). Again, there was interaction between Ca and NPP in diet on the contents of phosphorus (P) in serum (P < 0.05). In conclusion, interactions occurred between dietary Ca and NPP level on tibial breaking strength, density, ash content, and the content of P in the serum of young yellow-feathered broilers. Furthermore, dietary Ca affected ADFI, F:G and serum ALP activity, and dietary NPP also affected the P content in serum. Considering all indicators, 0.90% Ca and 0.40% NPP are optimal for slow-growing yellow-feathered broilers during 1–28 d of age. 相似文献