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   18552篇
  免费   1622篇
  国内免费   575篇
耳鼻咽喉   222篇
儿科学   351篇
妇产科学   434篇
基础医学   2295篇
口腔科学   318篇
临床医学   1357篇
内科学   4099篇
皮肤病学   320篇
神经病学   1018篇
特种医学   302篇
外国民族医学   1篇
外科学   2452篇
综合类   2239篇
一般理论   1篇
预防医学   1129篇
眼科学   199篇
药学   2011篇
  4篇
中国医学   666篇
肿瘤学   1331篇
  2024年   21篇
  2023年   294篇
  2022年   409篇
  2021年   1349篇
  2020年   949篇
  2019年   1292篇
  2018年   1393篇
  2017年   828篇
  2016年   594篇
  2015年   728篇
  2014年   1282篇
  2013年   1167篇
  2012年   1007篇
  2011年   1147篇
  2010年   901篇
  2009年   758篇
  2008年   775篇
  2007年   805篇
  2006年   626篇
  2005年   531篇
  2004年   489篇
  2003年   507篇
  2002年   309篇
  2001年   226篇
  2000年   212篇
  1999年   212篇
  1998年   316篇
  1997年   240篇
  1996年   143篇
  1995年   134篇
  1994年   116篇
  1993年   84篇
  1992年   84篇
  1991年   71篇
  1990年   48篇
  1989年   53篇
  1988年   63篇
  1987年   35篇
  1986年   39篇
  1985年   72篇
  1984年   66篇
  1983年   47篇
  1982年   58篇
  1981年   49篇
  1980年   54篇
  1979年   54篇
  1978年   33篇
  1977年   27篇
  1976年   14篇
  1974年   12篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
1.
2.
目的总结近年来股骨转子间骨折在稳定性重建方面的概念演化与研究进展。方法查阅国内外相关文献并结合自身经验,从股骨转子间骨折的解剖特点、稳定型骨折与不稳定型骨折分类、稳定性复位与不稳定性复位、术中加压初始稳定与术后滑动二次稳定、内固定术后稳定性评估、早期下地站立负重等方面进行总结分析。结果股骨转子间骨折发生于股骨颈干骺端转换区,具有天然的内翻不稳定倾向。骨折复位质量是影响后续内固定物安放的最重要前提因素。判断骨折复位质量有对线和对位两方面,对线采用 Garden 指数;在对位方面,随着皮质对位理念(正性、中性、负性)的提出,特别强调前内侧皮质的相互砥住支撑(解剖、正性),是获得骨折稳定性复位的关键,而不再强调后内侧小转子骨块的作用。术后影像学的稳定性评分为早期下地站立负重提供了量化指标。但术中的前内侧皮质支撑复位,在术后头颈骨块滑动获得二次稳定的过程中,仍有皮质对位丢失现象,需研究其危险因素和防范措施。结论股骨转子间骨折在取得良好对线的基础上,只要获得了前内侧皮质的相互砥住和支撑,并用内固定器械维持住,就获得了术后稳定性。术后稳定性评分优良者,可以安全地早期下地负重、站立行走活动。  相似文献   
3.
4.
Life expectancy for people with severe mental disorders is up to 25 years less in comparison to the general population, mainly due to diseases caused or worsened by smoking. However, smoking is usually a neglected issue in mental healthcare settings. The aim of this article is to describe a strategy to improve tobacco control in the hospital mental healthcare services of Catalonia (Spain). To bridge this gap, the Catalan Network of Smoke-free Hospitals launched a nationwide bottom-up strategy in Catalonia in 2007. The strategy relied on the creation of a working group of key professionals from various hospitals —the early adopters— based on Rogers’ theory of the Diffusion of Innovations. In 2016, the working group is composed of professionals from 17 hospitals (70.8% of all hospitals in the region with mental health inpatient units). Since 2007, tobacco control has improved in different areas such as increasing mental health professionals’ awareness of smoking, training professionals on smoking cessation interventions and achieving good compliance with the national smoking ban. The working group has produced and disseminated various materials, including clinical practice and best practice guidelines, implemented smoking cessation programmes and organised seminars and training sessions on smoking cessation measures in patients with mental illnesses. The next challenge is to ensure effective follow-up for smoking cessation after discharge. While some areas of tobacco control within these services still require significant improvement, the aforementioned initiative promotes successful tobacco control in these settings.  相似文献   
5.
Benzo[a]pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) in particulate matter that has a diameter of ≤2.5 μm (PM2.5). Studies have demonstrated that BaP exposure causes oocyte meiotic arrest in mice. However, whether BaP exposure also affects oocyte maturation in offspring remains unclear. To test this, female mice were administered BaP before pregnancy to generate BaP-exposed offspring. Our findings showed that BaP exposure reduced the in vitro maturation and increased the abnormalities of meiotic apparatus in offspring oocytes. In addition, BaP exposure reduced the mitochondrial content and intracellular ATP generation, induced early apoptosis, increased reactive oxidative species accumulation and the genomic DNA 5-methylcytosine (5mc) level in offspring oocytes. Along with the abovementioned defective parameters, maternal BaP exposure further compromised the embryo developmental competence of offspring oocytes. In summary, our study demonstrated that maternal BaP exposure compromised offspring oocyte maturation and quality.  相似文献   
6.

Purpose

Endovascular treatment with mechanical thrombectomy devices demonstrated high recanalization rates but functional outcome did not correlate with high rates of recanalization obtained. Patient selection prior to the endovascular treatment is very important in the final outcome of the patient. The primary aim of our study was to evaluate the prognostic value of posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) and Pons-Midbrain Index (PMI) scores in patients with Basilar Artery Occlusion (BAO) treated with successful angiographic recanalization after mechanical thrombectomy.

Methods

Retrospective single-center study including 18 patients between 2008 and 2013 who had acute basilar artery occlusion managed with endovascular treatment within 24 hours from symptoms onset and with successful angiographic recanalization. The patients were initially classified into two groups according to clinical outcome and mortality at 90 days. For analysis we also divided patients into groups based on pc-ASPECTS (≥8vs.< 8) and PMI (≥3vs.< 3) on non-contrast CT (NCCT) and CT Angiography Source Images (CTASI). Imaging data were correlated to clinical outcome and mortality rate.

Results

CTASI pc-ASPECTS, dichotomized at < 8 versus≥8, was associated with a favorable outcome (RR: 2.6; 95% CI: 1.3-5.2) and a reduced risk of death (RR: 6.5: 95% CI: 7.8-23.3). All patients that survived and were functionally independent had pc-ASPECTS score≥8. None of the 5 patients with CTASI pc-ASPECTS score less than 8 survived.

Conclusion

PC-ASPECTS on CTASI is helpful for predicting functional outcome after BAO recanalization with endovascular treatment. These results should be validated in a randomized controlled trial in order to decide whether or not to treat a patient with BAO.  相似文献   
7.
目的探讨改良内固定融合术治疗成人Ⅱ型痛性足副舟骨(painful accessory navicular,PAN)的疗效。方法2016 年 1 月—2017 年 12 月,采用改良内固定融合术治疗 29 例(37 足)Ⅱ型 PAN。其中男 12 例,女 17 例;年龄 18~50 岁,平均 41.4 岁。扭伤 24 例,无明显诱因 5 例。患者均行 6 个月以上保守治疗,症状无明显改善。术前及末次随访时采用美国矫形足踝协会(AOFAS)中足评分评估临床疗效;X 线片测量跟骨倾斜角、距骨第 1 跖骨角、距舟关节包容角、距骨第 2 跖骨角。结果术后 1 例出现切口浅表感染,经加强换药后愈合;其余患者切口均Ⅰ期愈合,无深部感染或骨髓炎发生。29 例均获随访,随访时间 12~33 个月,平均 25.1 个月。X 线片示关节面均于术后 2~5 个月愈合,平均 3.4 个月。随访期间未见内固定物松动或断裂。末次随访时,AOFAS 疼痛、功能、力线评分及总分以及距舟关节包容角、距骨第 1 跖骨角和距骨第 2 跖骨角均较术前显著改善,差异有统计学意义(P<0.05);跟骨倾斜角手术前后差异无统计学意义(t=1.097,P=0.276)。 结论采用改良内固定融合术治疗成人Ⅱ型 PAN 可有效缓解症状,患足功能恢复良好,并发症少。  相似文献   
8.
9.
Clinical trials are probably the most informative experiments to help an understanding of multiple sclerosis (MS) biology. Recent successes with CD20‐depleting antibodies have focused attention towards B cell subsets as important mediators in MS. The trial of tabalumab (NTC00882999), which inhibits B cell activation factor (BAFF), is reported and reviewed and this trial is contrasted with the trial on the inhibition of a proliferation‐inducing ligand (APRIL) and BAFF using atacicept (NCT00642902). Both tabalumab and atacicept induce depletion of mature B cells and inhibit antibody formation, but they fail to deplete memory B cells and do not inhibit relapsing MS. Atacicept is reported to augment memory B cell responses and may precipitate relapse, suggesting the importance of APRIL. However, BAFF inhibition can enhance peripheral blood memory B cell responses, which was not associated with augmented relapse. Although other interpretations are possible, these data further support the hypothesis that memory B cells may be of central importance in relapsing MS, as they are the major CD20+ B cell subset expressing APRIL receptors. They also suggest that quantitative and/or qualitative differences in B cell responses or other factors, such as an immune‐regulatory effect associated with APRIL, may be important in determining whether MS reactivates following neutralization of peripheral B cell maturation and survival factors.  相似文献   
10.
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