首页 | 官方网站   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   1252篇
  免费   115篇
  国内免费   51篇
医药卫生   1418篇
  2023年   14篇
  2022年   21篇
  2021年   48篇
  2020年   53篇
  2019年   38篇
  2018年   41篇
  2017年   34篇
  2016年   46篇
  2015年   30篇
  2014年   77篇
  2013年   122篇
  2012年   71篇
  2011年   72篇
  2010年   64篇
  2009年   66篇
  2008年   55篇
  2007年   71篇
  2006年   54篇
  2005年   74篇
  2004年   50篇
  2003年   39篇
  2002年   40篇
  2001年   28篇
  2000年   30篇
  1999年   17篇
  1998年   28篇
  1997年   16篇
  1996年   14篇
  1995年   4篇
  1994年   15篇
  1993年   15篇
  1992年   10篇
  1991年   8篇
  1990年   5篇
  1989年   2篇
  1988年   10篇
  1987年   1篇
  1986年   4篇
  1985年   5篇
  1983年   6篇
  1982年   1篇
  1981年   5篇
  1980年   5篇
  1979年   2篇
  1978年   3篇
  1976年   2篇
  1974年   1篇
  1972年   1篇
排序方式: 共有1418条查询结果,搜索用时 281 毫秒
51.
随着低剂量螺旋电子计算机断层扫描(computed tomography,CT)应用于肺癌高危人群中的筛查越来越普及,肺外周病变(peripheral pulmonary lesions,PPLs)发现概率也随之增加。电磁导航支气管镜(electromagnetic navigation bronchoscopy,ENB)是一种能够进行肺部外周病变诊断、定位及治疗的工具,由于它的安全性和可靠性更高,ENB在未来有可能会改变肺部疾病的诊断和治疗方式,从而缓解病情甚至治愈肺癌,为肺癌的治疗开辟了新的路径。  相似文献   
52.
目的通过采用不同治疗时间的脉冲电磁场(PEMFs)干预去势大鼠骨质疏松模型,观察各组大鼠的股骨生物力学性能的变化,以探索PEMFs治疗骨质疏松的最适治疗时间。方法按随机分组原则用密闭信封法将雌性3个月龄SD大鼠50只分为5组:假手术对照组10只,卵巢切除对照组10只,卵巢切除Ⅰ组10只,卵巢切除Ⅱ组10只,卵巢切除Ⅲ组10只。除假手术对照组以外,对所有动物按文献方法去势造模。卵巢切除Ⅰ组、卵巢切除Ⅱ组和卵巢切除Ⅲ组大鼠每天在强度为3.8mT,频率为8Hz的电磁场环境中分别照射20,40,60min,共30d。假手术对照组和卵巢切除对照组不干预。各组动物均在满30d后,行股动脉放血处死,取右侧股骨作生物力学性能测定。结果卵巢切除对照组大鼠的股骨结构力学指标(包括最大位移、最大载荷及最大能量吸收)和材料力学指标(包括最大应力、最大应变及弹性模量)显著低于其它4组大鼠(P〈0.05或P〈0.01),而假手术对照组、卵巢切除Ⅰ组、卵巢切除Ⅱ组及卵巢切除Ⅲ组4组大鼠的股骨生物力学指标之间的差异无统计学意义(P〉0.05)。结论PEMFs能阻止大鼠在卵巢切除后的股骨生物力学性能下降,对去势大鼠的骨质疏松症有肯定的预防作用。在磁场强度(3.8mT)和脉冲频率(8Hz)相同的前提下3种治疗时间的PEMFs均能使卵巢切除大鼠股骨生物力学性能维持在接近正常的水平,但3种治疗时间之间的差异无统计学意义,说明每日用PEMFs对去势大鼠治疗20—60min,对其骨生物力学性能的维持效果相同。  相似文献   
53.
54.
Strategies aiming at controlling and modulating inflammatory cues may offer therapeutic solutions for improving tendon regeneration. This study aims to investigate the modulatory effect of pulsed electromagnetic field (PEMF) on the inflammatory profile of human tendon-derived cells (hTDCs) after supplementation with interleukin-1β (IL-1β). IL-1β was used to artificially induce inflammatory cues associated with injured tendon environments. The PEMF effect was investigated varying the frequency (5 or 17 Hz), intensity (1.5, 4, or 5 mT), and duty-cycle (10% or 50%) parameters to which IL-1β-treated hTDCs were exposed to. A PEMF actuation with 4 mT, 5 Hz and a 50% duty cycle decreased the production of IL-6 and tumor necrosis factor-α (TNF-α), as well as the expression of TNFα, IL-6, IL-8, COX-2, MMP-1, MMP-2, and MMP-3, while IL-4, IL-10, and TIMP-1 expression increased. These results suggest that PEMF stimulation can modulate hTDCs response in an inflammatory environment holding therapeutic potential for tendon regenerative strategies. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:160–172, 2020  相似文献   
55.
目的探讨鲑鱼降钙素鼻喷剂结合脉冲电磁场治疗仪治疗骨质疏松性腰痛的临床疗效。方法选择2012年12月-2014年6月期间收治的骨质疏松性腰痛患者78例并按照随机数字表法分组为对照组和观察组,每组39例。对照组采用鲑鱼降钙素鼻喷剂治疗,观察组采用鲑鱼降钙素鼻喷剂结合脉冲电磁场治疗仪治疗。观察两组患者治疗前后疼痛评分情况及不良反应。结果治疗前观察组患者疼痛评分为(6.67±1.02)分与对照组(6.71±1.03)分比较,差异无统计学意义(P〉0.05)。治疗后观察组患者疼痛评分为(1.47±0.36)分,对照组为(3.69±0.53)分,两组患者均出现明显下降,但观察组优于对照组(P〈0.05)。此外,观察组不良反应率为2.56%(1/39)明显低于对照组10.26%(4/39)(P〈0.05)。结论骨质疏松性腰痛患者采用鲑鱼降钙素鼻喷剂结合脉冲电磁场治疗仪治疗,可有效缓解患者疼痛,且不良反应少。  相似文献   
56.

Purpose

It has been reported that even one year after total knee arthroplasty (TKA), a relevant percentage of patients does not attain complete recovery and indicate unfavourable long-term pain outcome. We compared the clinical outcome of 33 patients undergoing TKA randomly assigned to the control or the pulsed electromagnetic field group (I-ONE therapy).

Methods

I-ONE therapy was administered postoperatively four hours per day for 60 days. Patients were assessed before surgery and then at one, two and six months postoperatively using international scores.

Results

One month after TKA, pain, knee swelling and functional score were significantly better in the treated compared with the control group. Pain was still significantly lower in the treated group at the six month follow-up. Three years after surgery, severe pain and occasional walking limitations were reported in a significantly lower number of patients in the treated group.

Conclusions

Advantages deriving from early control of joint inflammation may explain the maintenance of results at follow-up. I-ONE therapy should be considered an effective completion of the TKA procedure.  相似文献   
57.
The increasing exposure to radiofrequency (RF) radiation emitted from mobile phone use has raised public concern regarding the biological effects of RF exposure on the male reproductive system. Autophagy contributes to maintaining intracellular homeostasis under environmental stress. To clarify whether RF exposure could induce autophagy in the spermatocyte, mouse spermatocyte-derived cells (GC-2) were exposed to 1800 MHz Global System for Mobile Communication (GSM) signals in GSM-Talk mode at specific absorption rate (SAR) values of 1 w/kg, 2 w/kg or 4 w/kg for 24 h, respectively. The results indicated that the expression of LC3-II increased in a dose- and time-dependent manner with RF exposure, and showed a significant change at the SAR value of 4 w/kg. The autophagosome formation and the occurrence of autophagy were further confirmed by GFP-LC3 transient transfection assay and transmission electron microscopy (TEM) analysis. Furthermore, the conversion of LC3-I to LC3-II was enhanced by co-treatment with Chloroquine (CQ), indicating autophagic flux could be enhanced by RF exposure. Intracellular ROS levels significantly increased in a dose- and time-dependent manner after cells were exposed to RF. Pretreatment with anti-oxidative NAC obviously decreased the conversion of LC3-I to LC3-II and attenuated the degradation of p62 induced by RF exposure. Meanwhile, phosphorylated extracellular-signal-regulated kinase (ERK) significantly increased after RF exposure at the SAR value of 2 w/kg and 4 w/kg. Moreover, we observed that RF exposure did not increase the percentage of apoptotic cells, but inhibition of autophagy could increase the percentage of apoptotic cells. These findings suggested that autophagy flux could be enhanced by 1800 MHz GSM exposure (4 w/kg), which is mediated by ROS generation. Autophagy may play an important role in preventing cells from apoptotic cell death under RF exposure stress.  相似文献   
58.
In this study, large-sized Al–Zn–Mg–Cu alloy billets were prepared by direct chill casting imposed with annular electromagnetic stirring and intercooling; a process named uniform direct chill casting. The effects of uniform direct chill casting on grain size and the alloying element distribution of the billets were investigated and compared with those of the normal direct chill casting method. The results show that the microstructures were refined and the homogeneity of the alloying elements distribution was greatly improved by imposing the annular electromagnetic stirring and intercooling. In uniform direct chill casting, explosive nucleation can be triggered, originating from the mold wall and dendrite fragments for grain refinement. The effects of electromagnetic stirring on macrosegregation are discussed with consideration of the centrifugal force that drives the movement of melt from the central part towards the upper-periphery part, which could suppress the macrosegregation of alloying elements. The refined grain can reduce the permeability of the melt in the mushy zone that can restrain macrosegregation.  相似文献   
59.
Zeolites are widely used in high-temperature oil refining processes such as fluid catalytic cracking (FCC), hydrocracking, and aromatization. Significant energy cost are associated with these processes due to the high temperatures required. The induction heating promoted by magnetic nanoparticles (MNPs) under radio frequency fields could contribute to solving this problem by providing a supplementary amount of heat in a nano-localized way, just at the active centre site where the catalytic process takes place. In this study, the potential of such a complementary route to reducing energetic requirements is evaluated. The catalytic cracking reaction under a hydrogen atmosphere (hydrocracking) applied to the conversion of plastics was taken as an application example. Thus, a commercial zeolite catalyst (H-USY) was impregnated with three different magnetic nanoparticles: nickel (Ni), cobalt (Co), maghemite (γ-Fe2O3), and their combinations and subjected to electromagnetic fields. Temperature increases of approximately 80 °C were measured for H-USY zeolite impregnated with γ-Fe2O3 and Ni-γ-Fe2O3 due to the heat released under the radio frequency fields. The potential of the resulting MNPs derived catalyst for HDPE (high-density polyethylene) conversion was also evaluated by thermogravimetric analysis (TGA) under hydrogen atmosphere. This study is a proof of concept to show that induction heating could be used in combination with traditional resistive heating as an additional energy supplier, thereby providing an interesting alternative in line with a greener technology.  相似文献   
60.
文题释义:低频脉冲电磁场(pulsed electromagnetic fields,PEMFs)疗法:是目前常用的骨质疏松症物理治疗方法。脉冲电磁场治疗骨质疏松症的原理是采用低频脉冲电磁场改变人体生物电、改善生物场,促使成骨细胞增生,增强成骨能力,提高骨密度治疗骨质疏松。 骨硬化蛋白的单克隆抗体(sclerostin antibody,Scl-Ab):对骨代谢的影响集中体现在对骨硬化蛋白的拮抗作用上。骨硬化蛋白单克隆抗体在刺激成骨活动的同时,不会刺激破骨活动,对骨合成代谢有显著刺激作用,其已经成为治疗骨质疏松的潜在方法。 背景:脉冲电磁场与骨硬化蛋白单克隆抗体皆能对绝经后新西兰大白兔骨代谢产生良好影响,但关于两者联合干预的效果至今少有报道。 目的:探讨脉冲电磁场联合骨硬化蛋白单克隆抗体对绝经后新西兰大白兔骨代谢的影响,探索其对骨质疏松症的治疗价值。 方法:采用卵巢切除法建立新西兰大白兔绝经后骨质疏松动物模型。将实验动物随机分为4组:卵巢切除组、脉冲电磁场组、骨硬化蛋白单克隆抗体组和脉冲电磁场+骨硬化蛋白单克隆抗体组,每组10只。术后第1天起,脉冲电磁场组给予脉冲电磁场磁疗每天1次;骨硬化蛋白单克隆抗体组给予骨硬化蛋白单克隆抗体皮下注射每周2次;脉冲电磁场+骨硬化蛋白单克隆抗体组接受脉冲电磁场磁疗每天1次、每周5次,骨硬化蛋白单克隆抗体皮下注射每周2次;卵巢切除组皮下注射相同剂量的生理盐水每周2次,干预共8周。8周后行骨代谢指标检查、骨密度测定、MicroCT骨微结构参数检测。动物研究中的所有程序经复旦大学实验动物科学部批准(20171263A193)。 结果与结论:①卵巢切除6个月新西兰大白兔骨密度显著下降,提示骨质疏松模型建立成功;②与卵巢切除组相比,3个治疗组L3椎体的骨密度均显著增加(P < 0.05);③3个治疗组血清骨特异性碱性磷酸酶水平均显著高于卵巢切除组,血清抗酒石酸酸性磷酸酶5b水平均显著低于卵巢切除组;脉冲电磁场+骨硬化蛋白单克隆抗体组血清抗酒石酸酸性磷酸酶5b的水平明显低于脉冲电磁场组、骨硬化蛋白单克隆抗体组;④脉冲电磁场+骨硬化蛋白单克隆抗体组骨微结构参数(骨体积分数、骨小梁厚度、骨小梁数量、骨小梁分离度)均优于脉冲电磁场组、骨硬化蛋白单克隆抗体组(均P < 0.05);⑤骨硬化蛋白单克隆抗体和脉冲电磁场联合治疗可以增强去势新西兰大白兔骨密度,改善骨代谢和骨微结构。 ORCID: 0000-0001-7052-4262(钱光) 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  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-23

京公网安备 11010802026262号