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   2953篇
  免费   165篇
  国内免费   33篇
耳鼻咽喉   17篇
儿科学   29篇
妇产科学   184篇
基础医学   277篇
口腔科学   275篇
临床医学   278篇
内科学   632篇
皮肤病学   31篇
神经病学   277篇
特种医学   139篇
外科学   502篇
综合类   5篇
一般理论   1篇
预防医学   90篇
眼科学   43篇
药学   110篇
中国医学   1篇
肿瘤学   260篇
  2024年   12篇
  2023年   31篇
  2022年   76篇
  2021年   140篇
  2020年   88篇
  2019年   92篇
  2018年   119篇
  2017年   74篇
  2016年   93篇
  2015年   91篇
  2014年   123篇
  2013年   141篇
  2012年   222篇
  2011年   217篇
  2010年   131篇
  2009年   115篇
  2008年   179篇
  2007年   197篇
  2006年   153篇
  2005年   202篇
  2004年   142篇
  2003年   131篇
  2002年   78篇
  2001年   28篇
  2000年   27篇
  1999年   27篇
  1998年   25篇
  1997年   22篇
  1996年   23篇
  1995年   12篇
  1994年   17篇
  1993年   7篇
  1992年   10篇
  1991年   18篇
  1990年   14篇
  1989年   7篇
  1988年   6篇
  1987年   6篇
  1986年   5篇
  1985年   4篇
  1984年   8篇
  1983年   6篇
  1982年   6篇
  1981年   3篇
  1979年   4篇
  1978年   3篇
  1976年   3篇
  1975年   4篇
  1974年   3篇
  1973年   3篇
排序方式: 共有3151条查询结果,搜索用时 0 毫秒
91.
BACKGROUND: Radiofrequency ablation (RFA) is a novel technique for the treatment of liver malignancies that is becoming increasingly more popular because of its feasibility, effectivity, repeatability, and safety. However, an increased number of complications after RFA has been reported in literature. The aim of this paper is to discuss the possible role of RFA in rapid intrahepatic spreading of hepatocellular carcinoma (HCC). PATIENTS AND METHODS: We treated a 66-year-old woman who had a 3.5-cm HCC with two courses of percutaneous RFA using a modified needle with seven hooks. The effectiveness of the treatment was assessed 1 month later by enhanced computed tomography. RESULTS: Two courses of treatment were needed owing to the nodule position (close to the inferior vena cava). Computed tomography scan performed 1 month after the second RFA showed an intrahepatic arteriovenous fistula. Angiography performed after 1 month showed a rapid intrahepatic spreading of HCC. CONCLUSIONS: Radiofrequency ablation can create an arteriovenous fistula that can facilitate migration of tumoral cells from the nodule to the hepatic portal system and rapid intrahepatic dissemination of HCC.  相似文献   
92.
BackgroundThe discovery of the prominent action of Calcitonin Gene Related Peptide –CGRP- on trigeminal afferents and meningeal vessels, opened a new era in migraine treatment. However, how the block of nociceptive afferents could act on central mechanisms of migraine is still not clear. In this pilot study we aimed to test the effect of 3 months Galcanezumab (CGA) therapy on occipital visual reactivity in migraine patients, using the Steady State Visual Evoked Potentials-SSVEPs and Functional Near Infrared Spectroscopy –fNIRS.MethodThirteen migraine patients underwent clinical and neurophysiological examination in basal condition (T0), 1 h after GCA injection (T1) and after 3 months of GCA treatment (T2). Ten healthy volunteers were also evaluated.ResultsAt T2, there was a reduction of headache frequency and disability. At T2, the EEG power significantly diminished as compared to T0 and T1 at occipital sites, and the topographical analysis confirmed a restoration of SSVEPs within normal values. The Oxyhemoglobin levels in occipital cortex, which were basically increased during visual stimulation in migraine patients, reverted to normal values at T2.ConclusionsThe present pilot study indicates that Galcanezumab could act on cortical targets located beyond the pain network, restoring the abnormal occipital reactivity. This effect could indicate the possible disease modifying properties of CGRP related monoclonal antibodies.  相似文献   
93.
Objectives

Tooth clenching has been suggested to be related to temporomandibular pain. However, the electromyographic characteristics of daytime clenching episodes have been minimally investigated. This study aimed to analyze the frequency, amplitude, and duration of daytime clenching episodes in patients with masticatory muscle pain and pain-free individuals.

Methods

Fifteen women with masticatory muscles myalgia (MP group, mean ± SD age = 26.4 ± 7.6 years) matched for age to 18 pain-free women (CTR group, mean ± SD age = 25.3 ± 2.8 years) were submitted to three different ability tasks (filling out questionnaires for 40 min, reading for 20 min, and playing a videogame for 20 min). The electromyographic activity periods (AP) of the right masseter greater than 10 % (AP10), 20 % (AP20), and 30 % (AP30) of the maximum voluntary contraction were analyzed.

Results

The mean frequencies of AP10, AP20, and AP30 were greater in MP than in CTR individuals (all p < 0.05). The mean duration of AP10 was higher in MP group than CTR group only while filling out the questionnaires (p = 0.0033). CTR group had an increased frequency and duration of AP10 while playing the videogame than while reading a magazine. The ability tasks did not affect the muscle activity in the MP group.

Conclusions

Individuals with masticatory muscle pain have an increased frequency of both high and low-intense daytime clenching episodes. The type of ability task affects the frequency and the duration of clenching episodes only in pain-free individuals.

Clinical relevance

Clinicians should recognize that the frequency and intensity of daytime clenching are noticeably increased in individuals with masticatory muscle pain in order to better tailor treatment.

  相似文献   
94.
OBJECTIVES: To compare the clinical outcomes of standard, cylindrical, screw-shaped to novel tapered, transmucosal (Straumann Dental implants immediately placed into extraction sockets. Material and methods: In this randomized-controlled clinical trial, outcomes were evaluated over a 3-year observation period. This report deals with the need for bone augmentation, healing events, implant stability and patient-centred outcomes up to 3 months only. Nine centres contributed a total of 208 immediate implant placements. All surgical and post-surgical procedures and the evaluation parameters were discussed with representatives of all centres during a calibration meeting. Following careful luxation of the designated tooth, allocation of the devices was randomly performed by a central study registrar. The allocated SLA titanium implant was installed at the bottom or in the palatal wall of the extraction socket until primary stability was reached. If the extraction socket was >or=1 mm larger than the implant, guided bone regeneration was performed simultaneously (Bio Oss and BioGide. The flaps were then sutured. During non-submerged transmucosal healing, everything was done to prevent infection. At surgery, the need for augmentation and the degree of wound closure was verified. Implant stability was assessed clinically and by means of resonance frequency analysis (RFA) at surgery and after 3 months. Wound healing was evaluated after 1, 2, 6 and 12 weeks post-operatively. RESULTS: The demographic data did not show any differences between the patients receiving either standard cylindrical or tapered implants. All implants yielded uneventful healing with 15% wound dehiscences after 1 week. After 2 weeks, 93%, after 6 weeks 96%, and after 12 weeks 100% of the flaps were closed. Ninety percent of both implant designs required bone augmentation. Immediately after implantation, RFA values were 55.8 and 56.7 and at 3 months 59.4 and 61.1 for cylindrical and tapered implants, respectively. Patient-centred outcomes did not differ between the two implant designs. However, a clear preference of the surgeon's perception for the appropriateness of the novel-tapered implant was evident. CONCLUSIONS: This RCT has demonstrated that tapered or standard cylindrical implants yielded clinically equivalent short-term outcomes after immediate implant placement into the extraction socket.  相似文献   
95.
PURPOSE: To estimate which combination of restorative materials resulted in the most homogeneous stress and strain distributions in post-and-core treated teeth. MATERIALS AND METHODS: Eight experimental finite element models with different material configurations were simulated; both indirect and direct restorations were considered. An arbitrary load of 50 N was applied on the palatal surface of the crown at a 60-degree angle to the tooth's longitudinal axis to simulate tearing function. RESULTS: In all the models, the values of both strain and stress recorded in the middle third of the buccal aspect of the root surface were off the scale. In contrast, the minimum values were noticed at the level of both the apical portion of the post and the root apex. CONCLUSION: The mechanical properties of the crown and core materials influenced both the position of concentration areas and the level of stress and strain along the dentin/cement/post interfaces.  相似文献   
96.
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