首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8472篇
  免费   500篇
  国内免费   48篇
耳鼻咽喉   123篇
儿科学   282篇
妇产科学   167篇
基础医学   1415篇
口腔科学   454篇
临床医学   612篇
内科学   1882篇
皮肤病学   217篇
神经病学   721篇
特种医学   115篇
外科学   891篇
综合类   32篇
一般理论   4篇
预防医学   734篇
眼科学   158篇
药学   628篇
中国医学   50篇
肿瘤学   535篇
  2024年   6篇
  2023年   67篇
  2022年   187篇
  2021年   313篇
  2020年   196篇
  2019年   255篇
  2018年   325篇
  2017年   189篇
  2016年   239篇
  2015年   244篇
  2014年   379篇
  2013年   505篇
  2012年   730篇
  2011年   766篇
  2010年   401篇
  2009年   321篇
  2008年   636篇
  2007年   567篇
  2006年   523篇
  2005年   429篇
  2004年   418篇
  2003年   407篇
  2002年   348篇
  2001年   50篇
  2000年   43篇
  1999年   48篇
  1998年   56篇
  1997年   37篇
  1996年   33篇
  1995年   30篇
  1994年   25篇
  1993年   23篇
  1992年   22篇
  1991年   18篇
  1990年   14篇
  1989年   30篇
  1988年   21篇
  1987年   9篇
  1986年   15篇
  1985年   12篇
  1984年   17篇
  1983年   6篇
  1982年   9篇
  1981年   6篇
  1980年   6篇
  1977年   5篇
  1976年   6篇
  1973年   3篇
  1970年   3篇
  1967年   6篇
排序方式: 共有9020条查询结果,搜索用时 0 毫秒
91.
Background The immunohistochemical expression of vascular endothelial growth factor is a prognostic marker in several cancer types. In salivary gland tumors, the association between vascular endothelial growth factor and prognosis remains unclear. The purpose of this study was to perform a systematic review and meta-analysis to assess whether the immunohistochemical expression of vascular endothelial growth factor in patients with salivary gland neoplasms presents prognostic value. Material and Methods Immunohistochemical studies assessing the predictive value of vascular endothelial growth factor in salivary gland neoplasms were systematically reviewed using PubMed, Scopus, Embase, Cochrane Library, and Web of Science databases. It was assessed any survival rates. The fixed-effect model with an adjusted hazard ratio (HR) and 95% confidence intervals (95% CI) as effect measures were performed in the meta-analysis. The Quality in Prognosis Studies (QUIPS) tool was used to assess the quality of the included studies, and the evidence quality was assessed by the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) system. Results The immunohistochemical overexpression of vascular endothelial growth factor in patients with salivary gland neoplasms was associated with shortened survival (HR=5.37, 95% CI: 2.67-10.83, P = 0.00001). In addition, the presence of vascular endothelial growth factor was tightly associated with tumor size, lymph node metastasis, clinical stage, perineural invasion, vascular invasion, poor local control of the disease, and recurrence. Conclusions The immunohistochemical overexpression of vascular endothelial growth factor in patients with salivary gland neoplasms has prognostic value and was associated with decreased survival time. However, more primary well-designed studies are necessary to increase the level of evidence. Key words:Salivary gland neoplasms, salivary glands, head and neck neoplasms, vascular endothelial growth factors, prognosis.  相似文献   
92.
Clinical Oral Investigations - The aim of this study was to analyze the influence of dietary fatty acids (FAs) and the time elapsed from their intake on FA tissue profile of rat submandibular gland...  相似文献   
93.
94.
95.

Background

A complication of diabetes is neuropathy, a condition of sensory axon degeneration that originates in the epidermis. The mechanisms remain unknown but reactive oxygen species (ROS) have been implicated in this condition. In this study, we assessed the role of ROS and a candidate downstream target, MMP-13 in glucose-induced sensory axon degeneration in zebrafish and mice.

Methods

The effects of glucose on metabolism and sensory axon degeneration were assessed using qPCR and live imaging. ROS were analyzed using pentafluorobenzene-sulfonyl fluorescein and activation of the NF-κB stress response was determined using Tg(NF-κB:GFP) zebrafish. The role of MMP-13 and ROS in glucose-dependent axon degeneration was determined in zebrafish following treatment with the antioxidant, N-acetylcysteine and the MMP-13 inhibitor, DB04760. Neuropathic mice fed on a high-fat/high-sugar diet were treated with the MMP-13 inhibitor, CL-82198 to assess sensory recovery.

Results

Glucose treatment of zebrafish induced metabolic changes that resemble diabetes. Sensory axon degeneration was mediated by ROS-induced MMP-13 and prevented upon antioxidant treatment or MMP-13 inhibition. MMP-13 inhibition also reversed neuropathy in diabetic mice.

Conclusion

We demonstrate that zebrafish are suitable to study glucose-induced neurotoxicity. Given the effects in zebrafish and mice, MMP-13 inhibition may be beneficial in the treatment of human diabetic neuropathy.  相似文献   
96.
Background: Previous studies have demonstrated that bone demineralization can improve consolidation in bone grafts. The biologic mechanisms underlying this phenomenon remain unclear. Methods: Twelve adult male guinea pigs were used in this experiment. Forty‐five bone samples removed from the calvaria of nine animals were divided in groups (n = 9) according to the time of demineralization with citric acid (50%, pH 1): 15, 30, 90, and 180 seconds and non‐demineralized samples (control). Preosteoblasts (MC3T3‐E1) were cultured on the bone samples for 24, 48, and 72 hours (n = 3). Fifteen samples removed from the remaining three animals were analyzed by scanning electron microcopy/energy dispersive spectrometry (SEM/EDS) after demineralization (n = 3). Results: The number of preosteoblasts increased significantly with time in all groups. The bone surface area covered by these cells increased with time, except in the control group. Intragroup differences occurred between 24 and 72 hours (P <0.05). Samples demineralized for 30 seconds showed greater area covered by preosteoblast cells than for the other times of demineralization in all periods of cell culture (P <0.05) without a statistically significant difference compared with 15 seconds. SEM/EDS showed diminished content of calcium (Ca) after 15 seconds of demineralization, but the Ca content increased after 180 seconds of demineralization (P <0.05). The phosphorus (P) amount increased significantly only after 30 seconds of demineralization (P <0.5). The sulfur (S) content was increased in demineralized samples in relation to non‐demineralized ones, reaching the highest level after 90 seconds, when the difference became significant in relation to all the other times of demineralization (P <0.05). Magnesium (Mg) content did not differ significantly between demineralized and non‐demineralized samples. Conclusions: Bone surfaces demineralized for 30 seconds increased the spreading of preosteoblasts as well as the surface area covered by these cells. Bone demineralization deserves to be studied in periodontal and maxillofacial regenerative procedures.  相似文献   
97.
98.
99.
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号