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   805篇
  免费   35篇
  2024年   1篇
  2023年   3篇
  2022年   25篇
  2021年   39篇
  2020年   21篇
  2019年   22篇
  2018年   16篇
  2017年   23篇
  2016年   41篇
  2015年   41篇
  2014年   38篇
  2013年   55篇
  2012年   89篇
  2011年   65篇
  2010年   40篇
  2009年   32篇
  2008年   45篇
  2007年   42篇
  2006年   39篇
  2005年   35篇
  2004年   34篇
  2003年   21篇
  2002年   16篇
  2001年   6篇
  1999年   5篇
  1998年   2篇
  1997年   2篇
  1996年   7篇
  1995年   2篇
  1994年   3篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   7篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1979年   2篇
  1972年   1篇
  1954年   1篇
  1952年   1篇
排序方式: 共有840条查询结果,搜索用时 31 毫秒
831.

Width of attached gingiva plays an important role in maintaining periodontal health, provides stabilization of the gingival margin against frictional forces and aids in dissipating physiological forces exerted by the muscular fibers of the alveolar mucosa on the gingival tissues. Inadequate width of attached gingiva leads to attachment loss, soft tissue recession, and impedes oral hygiene measures. Hence, procedures using autografts and allografts have been proposed to augment the attached gingiva. Allografts like chorionic membrane (CM) are known to enhance release of growth factors, promote neovascularization, healing and enhance biotype. To assess the efficacy of CM in increasing the width of attached gingiva, vestibular depth and gingival thickness. Fifteen patients with inadequate attached gingival width were included in the study. Patients were randomly allocated to each group: Control group, CM group and CM?+?platelet rich fibrin (PRF) group. Attached gingiva width, vestibular depth, and gingival thickness were measured at baseline and 4 weeks post procedure. The control, CM and CM?+?PRF groups showed an increase in all parameters from baseline to 4 weeks. The increase in the attached gingiva (p?=?0.042) width, vestibular depth (p?=?0.043) and gingival thickness (p?=?0.034) were statistically significant at 4 weeks for CM group and CM?+?PRF group respectively. The CM?+?PRF group showed better results compared to other groups. CM and PRF can be effectively incorporated to increase the width of attached gingiva and depth of vestibule.

  相似文献   
832.
Sweet orange has great socioeconomic value in India and other parts of the world for their important role in human diet and other properties like sweet flavour, sweet aroma, source of vitamin C etc. Despite its numerous commercial values, and large acreages under cultivation little has been studied on the role of sweet orange orchards in carbon management and environmental sustainability. Therefore, the present study was conducted to (1) develop appropriate models for estimation of sweet orange tree biomass, and (2) assess biomass and ecosystem carbon stock for sweet orange orchards in North East India. Allometric models for biomass estimation were developed using data from 58 harvested orange trees. The height-diameter relationships and allometric scaling between above-ground biomass (AGB), culm height (H) and diameter at breast height (D) were examined using various models. Total biomass carbon and soil organic carbon stock of the sweet orange orchard were estimated at 7.69 and 100.2 Mg C ha?1 respectively. Our finding on biomass carbon stock of the sweet orange orchard was comparable with other fruit orchards across the world. However, the age of the orchard and management systems are two major determinants for carbon sink potential of such systems. We recommend upscaling of sweet orange based agroforestry for restoration of degraded shifting cultivated lands in North East India for environmental sustainability and socioeconomic upliftment of the farmers.  相似文献   
833.
834.
835.
Journal of Plant Growth Regulation - Metal-based nanoparticles (NPs) have recently been accomplished a great attention worldwide, in various sectors including agriculture due to their beneficial...  相似文献   
836.
The influence of various inducing agents on growth, synthesis and release of klebocin byKlebsiella pneumoniae was studied. A significant level of klebocin was detected only after induction. The highest level of klebocin was achieved with mitomycin C followed by rifampicin and polymyxin B. Chloramphenicol and UV irradiation did not show any effect on klebocin production. Maximum klebocin release occurred after 8 h of induction with all the agents. Concentration of mitomycin C did not show any significant effect on klebocin production.  相似文献   
837.

Cerebral ischemia is a cerebrovascular disease with high morbidity and mortality that poses a significant burden on society and the economy. About 60% of cerebral ischemia is caused by thrombus, and the formation of thrombus proceeds from insoluble fibrin, following its transformation from liquid fibrinogen. In thrombus-induced ischemia, increased permeability of the blood–brain barrier (BBB), followed by the extravasation of blood components into the brain results in an altered brain microenvironment. Changes in the brain microenvironment affect brain function and the neurovascular unit (NVU), the working unit of the brain. Recent studies have reported that coagulation factors interact with the NVU and its components, but the specific function of this interaction is highly speculative and warrants further investigations. In this article, we reviewed the role of coagulation factors in cerebral ischemia and the role of coagulation factors in thrombosis. Additionally, the influence of thrombin on the NVU is introduced, as well as in the function of NVU, which may help to explore part of brain injury mechanism during ischemia. Lastly, we propose some novel therapeutic approaches on ischemic stroke by reducing the risk of coagulation.

  相似文献   
838.
839.
A series of 3α-amino-5α-cholestane and 3α,7α-diamino-5α-cholestane derivatives containing imidazole and pyridine rings were synthesized by simple and effective reductive amination, and their in vitro activities against a range of Gram-positive and Gram-negative strains were evaluated. Most of the compound exhibited enhanced activity against MRSA pathogen. 3α,7α-Di(pyridylmethyl)amino-5α-cholestane 10 showed the highest potency in these series toward the Gram-positive bacteria, Staphylococcus epidermidis 887E, with the lowest MIC value of 1 μg/mL.  相似文献   
840.
Multidrug-resistant (MDR) clinical isolates ofKlebsiella pneumoniae were checked for their sensitivity toward silver nitrate by the tube-dilution method. Nearly 75% of MDR strains clould be successfully inhibited by 5 mg/L of silver nitrate. A significant correlation was observed between incidence of silver and trimoxazole resistance and silver and kanamycin resistance in these isolates. The genetic linkage of these two properties could not be proved since simultaneous curing and co-transfer studies gave negative results.  相似文献   
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