全文获取类型
收费全文 | 540篇 |
免费 | 41篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 18篇 |
妇产科学 | 3篇 |
基础医学 | 85篇 |
口腔科学 | 38篇 |
临床医学 | 67篇 |
内科学 | 99篇 |
皮肤病学 | 13篇 |
神经病学 | 17篇 |
特种医学 | 34篇 |
外科学 | 100篇 |
综合类 | 15篇 |
一般理论 | 1篇 |
预防医学 | 30篇 |
眼科学 | 18篇 |
药学 | 66篇 |
中国医学 | 2篇 |
肿瘤学 | 25篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 30篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 25篇 |
2017年 | 30篇 |
2016年 | 22篇 |
2015年 | 22篇 |
2014年 | 19篇 |
2013年 | 22篇 |
2012年 | 20篇 |
2011年 | 28篇 |
2010年 | 26篇 |
2009年 | 24篇 |
2008年 | 29篇 |
2007年 | 54篇 |
2006年 | 31篇 |
2005年 | 19篇 |
2004年 | 16篇 |
2003年 | 9篇 |
2002年 | 13篇 |
2001年 | 15篇 |
2000年 | 16篇 |
1999年 | 11篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 14篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有635条查询结果,搜索用时 0 毫秒
1.
Jennifer C. Chen Katrina L. Schmid Brian Brown Marion H. Edwards Bibianna SY Yu John KF Lew 《Clinical & experimental optometry》2003,86(5):323-330
Purpose: Caucasian children with myopia have elevated response accommodative vergence to accommodation (AC/A) ratios. The purpose of this study was twofold: to determine if response AC/A ratios vary with refractive error and with myopic progression rate in Hong Kong Chinese children, and to determine the effect of beta‐adrenergic antagonism with topical timolol application on AC/A ratios. Methods: Thirty children aged eight to 12 years participated in the study. All refractive errors were corrected with spectacle lenses. Accommodative responses were measured using a Shin‐Nippon autorefractor and concurrent changes in vergence were assessed using a vertical prism and a Howell‐Dwyer card at three metres and 0.33 metre. Accommodative demand was altered using plus or minus two dioptre lenses and lens‐ and distance‐induced response AC/A ratios were calculated. Measurements were repeated 30 minutes after the instillation of topical timolol maleate (0.5 per cent). Results: AC/A ratios appeared higher in progressing myopic children but the difference was not statistically significant. Timolol application reduced accommodative convergence (AC) in the stable myopes (reduction = ‐3 ± 1.14A) but not in the emmetropes (0.69 ± 0.9P) or progressing myopes (0.16 ± 0.43A) and this difference between refractive groups was statistically s ignificant (F2,27= 3.766; P= 0.036). However, timolol did not produce a significant change in the accommodative response to positive or negative lenses or response AC/A ratios. Conclusions: We did not find that AC/A ratios in myopic Chinese children were elevated and therefore, it is unlikely that elevated AC/A ratios are responsible for the high levels of myopia that occur in Hong Kong. The finding that timolol reduced AC in the stable myopes suggests that the autonomic control of accommodative convergence in these children may be different from that in emmetropic children and those with progressing myopia. 相似文献
2.
García-González M Abdulkader I Boquete AV Neo XM Forteza J Cameselle-Teijeiro J 《Virchows Archiv : an international journal of pathology》2005,447(1):12-17
This study was undertaken to investigate cyclooxygenase-2 (COX-2) expression in follicular cells of the human thyroid. COX-2 expression was studied immunohistochemically in a total of 174 samples. COX-2 immunoreactivity was confined to the cell cytoplasm with the nuclei remaining unlabelled. COX-2 expression was observed in five cases (17.2%) of normal follicular cells and in one case (16.6%) of solid cell nests. Follicular carcinoma expressed COX-2 more frequently than follicular adenoma (93.4% vs 21.1%) (p0.001). A higher percentage of cases of papillary microcarcinomas up-regulated COX-2 in comparison with all papillary carcinomas (p0.05). However, we could not establish any relationships among COX-2, patients ages or lymph node metastases in papillary carcinomas. COX-2 expression was found in 12 (92.3%) poorly differentiated carcinomas and in 13 (92.8%) undifferentiated carcinomas. We found that COX-2 is not always useful as a marker of malignancy. Our results suggest that COX-2 plays a role in progression of all thyroid carcinomas, but in papillary carcinomas, seems more important only in the early stages. COX-2 expression in the undifferentiated carcinoma deserves special consideration due to its prognosis and to the fact that selective COX-2 inhibitors were found to enhance tumour response to radiation in some studies. 相似文献
3.
Nishio K Neo M Akiyama H Okada Y Kokubo T Nakamura T 《Journal of biomedical materials research》2001,55(2):164-176
Previously we developed a composite consisting of apatite and wollastonite containing glass-ceramic (AW-GC) powder and bisphenol-a-glycidyldimethacrylate (Bis-GMA)-based resin (designated AWC), and demonstrated that AWC showed direct contact with living bone. Another new composite consisting of mainly the delta-crystal phase of alumina bead powder and Bis-GMA-based resin (designated ABC) was developed. Although alumina ceramics are bioinert and a composite filled with the pure alpha-crystal phase of alumina powder (designated alphaALC) did not allow direct bone formation in vivo, ABC was shown to have excellent osteoconductivity. One purpose of this study was to investigate whether AW-GC powder in a composite promotes osteoblastic differentiation of rat bone marrow cells as AW-GC bulk did. Another purpose was to evaluate the effects of the delta-crystal phase of alumina powder in a composite on osteoblastic differentiation. In a cell culture with dexamethasone, alkaline phosphatase (AP) activity at both days 7 and 14, and the levels of osteocalcin mRNA and alpha1(I) collagen mRNA at day 14 and osteopontin mRNA at day 7, were highest on AWC, followed by ABC, and finally alphaALC. Scanning electron microscopy showed more abundant mineralized globules and a fibrous collagen matrix on AWC at day 14, followed by ABC. In a cell culture without dexamethasone, AP activity at both days 7 and 14, and the level of osteopontin mRNA at day 7, were higher on ABC than on any other composite, whereas osteocalcin mRNA could not be detected. These results indicate that AW-GC powder in a composite promotes osteoblastic differentiation of bone marrow cells intensively when supplemented with dexamethasone. The delta-crystal phase of alumina powder in a composite promotes greater osteoblastic differentiation than the alpha-crystal phase of alumina powder. 相似文献
4.
Nobuhiro Okuno Shuhei Otsuki Jo Aoyama Kosuke Nakagawa Tomohiko Murakami Kuniaki Ikeda Yoshinobu Hirose Hitoshi Wakama Tomohiro Okayoshi Yoshinori Okamoto Yoshiaki Hirano Masashi Neo 《Journal of orthopaedic research》2021,39(1):165-176
The inner avascular zone of the meniscus has limited healing capacity as the area is poorly vascularized. Although peptide hydrogels have been reported to regenerate bone and cartilage, their effect on meniscus regeneration remains unknown. We tested whether the self‐assembling peptide hydrogel scaffold KI24RGDS stays in the meniscal lesion and facilitates meniscal repair and regeneration in an induced rabbit meniscal defect model. Full‐thickness (2.0 mm diameter) cylindrical defects were introduced into the inner avascular zones of the anterior portions of the medial menisci of rabbit knees (n = 40). Right knee defects were left empty (control group) while the left knee defects were transplanted with peptide hydrogel (KI24RGDS group). Macroscopic meniscus scores were significantly higher in the KI24RGDS group than in the control group at 2, 4, and 8 weeks after surgery. Histological examinations including quantitative and qualitative scores indicated that compared with the control group, the reparative tissue in the meniscus was significantly enhanced in the KI24RGDS group at 2, 4, 8, and 12 weeks after surgery. Immunohistochemical staining showed that the reparative tissue induced by KI24RGDS at 12 weeks postimplantation was positive for Type I and II collagen. KI24RGDS is highly biocompatible and biodegradable, with strong stiffness, and a three dimensional structure mimicking native extracellular matrix and RGDS sequences that enhance cell adhesion and proliferation. This in vivo study demonstrated that KI24RGDS remained in the meniscal lesion and facilitated the repair and regeneration in a rabbit meniscal defect model. 相似文献
5.
Modupeola Diyaolu Anne-Laure Thomas Lauren SY Wood Jordan Taylor James CY Dunn 《Journal of pediatric surgery》2021,56(1):5-10
BackgroundShort gut syndrome, a condition characterized by inadequate absorption of nutrients owing to decreased bowel length, has minimal avenues for treatment. We have proposed spring-mediated distraction enterogenesis to lengthen bowel in porcine jejunum as a treatment for short gut. We aim to evaluate the extent of mesenteric neovascularization in segments of lengthened bowel via spring-mediated enterogenesis.MethodsFemale juvenile Yucatan pigs underwent laparotomy and insertion of gelatin-encapsulated compressed nitinol springs, held in place with plication sutures, into the jejunum. At surgery and sacrifice, macroscopic mesenteric blood vessels were counted between the plication sites. Histologic samples of the mesentery were obtained to evaluate microscopic vasculature.ResultsA statistically significant increase in macroscopic mesenteric blood vessels was seen after intestinal lengthening (before: 1.9 ± 0.7 vessels, after: 4.7 ± 1.2 vessels, p = 0.001). A statistical significance is also seen in the density of arterioles (control: 3.0 ± 3.0 vessels/mm, spring: 7.0 ± 9.0 vessels/mm, p = 0.01) and venules (control: 4.0 ± 3.0 vessels/mm, spring: 8.0 ± 8.0 vessels/mm, p = 0.003).ConclusionIntestinal segments lengthened by intraluminal springs demonstrated total greater number of macroscopic vessels and microscopic blood vessels per length of mesentery as compared to control. This suggests local changes within the mesentery to recruit blood supply to growing intestine.Level of evidenceN/AType of studyTreatment study. 相似文献
6.
7.
The impact of a Web‐based educational program on the recognition and management of deteriorating patients 下载免费PDF全文
8.
Noor H. A. Suaini Evelyn Xiu-Ling Loo Rachel L. Peters Gaik Chin Yap Katrina J. Allen Hugo Van Bever David J. Martino Anne Eng Neo Goh Shyamali C. Dharmage Marjorelee T. Colega Mary Foong Fong Chong Anne-Louise Ponsonby Kok Hian Tan Mimi L. K. Tang Keith M. Godfrey Bee Wah Lee Lynette Pei-Chi Shek Jennifer J. Koplin Elizabeth Huiwen Tham 《Allergy》2021,76(10):3171-3182
9.
10.
Hassan Aboul Nour Neo Poyiadji Ghada Mohamed Owais K Alsrouji Ahmad-Riad Ramadan Brent Griffith Horia Marin Alex Bou Chebl 《Interventional neuroradiology》2021,27(3):434
Large vessel occlusion in patients on ECMO is challenging to appreciate clinically secondary to sedation or induced paralysis, thus placing more emphasis on neurovascular imaging. However, emergent CTA and CTP are both inaccurate and unreliable in ECMO patients due to altered circuitry and interference with normal physiologic hemodynamics. In this review, the utility of DSA is discussed in evaluating the altered hemodynamics of VA-ECMO circuits and patency of major vasculature. In addition, the potential use of TCD in ECMO patients is discussed. 相似文献