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   2120篇
  免费   220篇
  国内免费   144篇
耳鼻咽喉   3篇
儿科学   8篇
妇产科学   14篇
基础医学   121篇
口腔科学   18篇
临床医学   152篇
内科学   142篇
皮肤病学   12篇
神经病学   75篇
特种医学   60篇
外科学   88篇
综合类   392篇
预防医学   54篇
眼科学   8篇
药学   306篇
  6篇
中国医学   928篇
肿瘤学   97篇
  2024年   18篇
  2023年   109篇
  2022年   197篇
  2021年   174篇
  2020年   208篇
  2019年   157篇
  2018年   114篇
  2017年   105篇
  2016年   109篇
  2015年   121篇
  2014年   210篇
  2013年   178篇
  2012年   243篇
  2011年   168篇
  2010年   116篇
  2009年   81篇
  2008年   37篇
  2007年   26篇
  2006年   25篇
  2005年   9篇
  2004年   4篇
  2003年   4篇
  2002年   5篇
  2001年   7篇
  2000年   6篇
  1999年   11篇
  1998年   8篇
  1997年   3篇
  1996年   2篇
  1995年   5篇
  1994年   3篇
  1993年   6篇
  1992年   1篇
  1991年   2篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
排序方式: 共有2484条查询结果,搜索用时 31 毫秒
21.
A maternity testing case is reported, in which the child showed tri-allelic patterns in two short tandem repeat (STR) loci. The genotypes of Penta D of the mother and the child were 9,13 and 9,10,13, respectively. Those of D21S11 were 32.2,35 and 29,35, respectively, but intensity ratio of alleles 29 and 35 of the child was 1:2. These results suggested the copy number variations (CNVs) or trisomy of chromosome 21. By further examination using STR-based chromosome aneuploidy detection kit, three alleles were detected in D21S1411, LFG21 and Penta D, and 2 alleles with intensity ratio of 1:2 were observed in D21S2502, D21S1435, D21S11 and D21S1246. Karyotype and whole-genome SNP array analyses showed that the child had a free trisomy 21. In addition, partially homologous non-sister chromatid crossover occurred at the region 19181770-39499178 on the long arm of chromosome 21.  相似文献   
22.
ObjectiveThe frontal basal interhemispheric approach (FBIA) is preferable for resection of craniopharyngioma (CP), achieving desirable total resection rates in early reports of lesions located in the suprasellar region to the third ventricle. For tumours that have created a larger obstruction of the tuberculum sellae and planum sphenoidale, aggressive resection in the intrasellar region and medial wall of the cavernous sinus is not feasible compared to improving tumour visualization by drilling the tuberculum sellae and planum sphenoidale. In a report of drilling the sellar tuberculum and sphenoid planum, drilling allowed the direct visualization of tumours invading the intrasellar region and medial wall of the cavernous sinus. Reconstructing the opening of the sellar-sphenoid cavity is achieved by microsuturing a piece of the pericranium/dura around the dural edge of the defective dura of the open sphenoid sinus and sellar cavity to prevent cerebrospinal fluid (CSF) leakage.Patients and methodsThe FBIA with drilling of the tuberculum sellae and planum sphenoidale was performed to remove the tumours that invaded the intrasellar region and cavernous sinus in 55 patients from January 2014 to October 2019 at our institution. The pre- and postoperative pituitary hormone levels and vision were evaluated as effective standards after surgery and compared using paired t-tests. The different rates of CSF leakage between the packing and microsuture groups were compared by χ2 test, p < 0.05.ResultsIn all patients with a mean 37-month follow-up (range, 3–2 months), 43 (78.2%) patients returned to their normal life or school independently, 7 (12.7%) patients were able to perform normal activities with minor complaints or effort, and 4 (7.3%) patients could care for themselves or only required occasional assistance. One (1.8%) death occurred, attributed to CSF leak-related meningitis at 5 months after surgery. Postoperative CSF leakage occurred in eight (19.0%) of 42 patients with packed bone wax or pieces of muscle to the sphenoid sinus. Of 13 patients with a piece of the periosteum/dura microsutured around the defective dura of the sellar region and open sphenoid sinus, one (7.7%) of 13 patients experienced CSF leakage in the perioperative period. With statistical analysis, there was a potential risk for postoperative CSF leakage in the bone wax and muscle piece in the open sphenoid sinus, whereas microsuture manoeuvres were effective for avoiding the risk of postoperative CSF leakage (χ2 = 8.865, p < 0.005). The microsutures closed the open sphenoid sinus such that it was water-tight. Postoperative visual acuity and the visual field were not affected by the increased intrasellar exposure or the open sphenoid sinus achieved by drilling the tuberculum sellae and planum sphenoidale.ConclusionTuberculum sellae/planum sphenoidale drilling via FBIA is feasible to enhance the direct visualization of CP resection, which expands the intrasellar region with a direct resection of recurrent tumours in the sellar cavity and adhering to the medial wall of the cavernous sinus. The potential risk of a CSF leakage seemed to be mitigated when using water-tight microsutures on a piece of the pericranium/dura around the edge of the defective dura in the sellar region and the open sphenoid sinus cavity.  相似文献   
23.
目的:系统评价温针灸联合玻璃酸钠治疗膝骨性关节炎的疗效。方法:计算机检索自建库截止至2018年7月PubMed,Wed of Science CBM,The Cochrane Library,EMBase,中国期刊全文数据库(CNKI)、万方数据库(Wan Fang Data)、维普中文科技期刊数据库(VIP)中关于温针灸联合玻璃酸钠治疗膝骨性关节炎的随机对照试验(RCTs)。由2位研究员分别进行文献筛选、数据提取和质量评价后,采用Rev Man 5.3软件进行Meta分析。结果:有15篇RCTs纳入本研究,共1247例膝骨性关节炎患者(试验组628例,对照组619例)。试验组:温针灸联合玻璃酸钠;对照组:玻璃酸钠/温针灸/其他治疗。Meta分析结果:试验组治疗膝骨性关节炎总有效率比玻璃酸钠组、温针灸组、其他组分别高15%、20%及24%,且差异有统计学意义(RR=1.15,95%CI:1.10~1.21,P<0.00001;RR=1.20,95%CI:1.05~1.36,P=0.005;RR=1.36,95%CI:1.11~1.66,P=0.003)。试验组治疗膝骨性关节炎改善视觉模拟(VAS)评分优于玻璃酸钠组、温针灸组及其他组,且差异有统计学意义(MD=-1.46,95%CI:-1.84~-1.08,P=0.009;MD=-4.73,95%CI:-6.46~-3.01,P<0.00001;MD=-1.83,95%CI:-2.39~-1.28,P<0.00001);试验组治疗膝骨性关节炎改善WOMAC评分优于温针灸组,且差异有统计学意义(MD=-37.11,95%CI:-49.36~-24.85,P<0.00001)。试验组治疗膝骨性关节炎改善膝关节(LKSS)评分优于玻璃酸钠组及温针灸组,且差异有统计学意义(MD=39.14,95%CI:20.87~57.42,P<0.0001;MD=41.05,95%CI:27.77~54.33,P<0.00001)。结论:温针灸联合玻璃酸钠治疗膝骨性关节炎疗效优于单一用药及其他组,不过本研究纳入文献的质量及数量有限,故仍需更多长时间随访且高质量的RCTs试验进一步验证。  相似文献   
24.
目的:观察整脊推拿结合中药化痰祛瘀方治疗颈源性眩晕伴颈动脉斑块的的效果及安全性。方法:伴有颈动脉斑块的颈源性眩晕患者按随机数字表法分为两组,对照组45例采用基础治疗联合中药化痰祛瘀方,观察组43例在对照组基础上结合整脊推拿干预,治疗后统计比较两组眩晕指征和血脂改善情况。结果:治疗后两组患者眩晕、耳鸣、恶心欲呕、头痛、视力障碍、猝倒发作、颈项不适、反应迟钝等症状的恢复率比较,差异有统计学意义(P<0.01);治疗结束后观察组的总有效率为95.35%,明显优于对照组的77.78%,差异有统计学意义(P<0.05);疗程结束后两组患者血脂均较治疗前有所改善(P<0.05),观察组中的总胆固醇(TC)、低密度脂蛋白(LDL)明显低于对照组,高密度脂蛋白(HDL)明显高于对照组,差异均有统计学意义(P<0.05),但三酰甘油(TG)和对照组比较差异无统计学意义(P> 0.05)。结论:整脊推拿结合化痰祛瘀方治疗颈源性眩晕伴颈动脉斑块,在改善眩晕相关指征和血脂方面疗效较好。  相似文献   
25.
Brain functional connectivity (FC) derived from resting-state functional magnetic resonance imaging (rs-fMRI) has been widely employed to study neuropsychiatric disorders such as autism spectrum disorder (ASD). Existing studies usually suffer from (1) significant data heterogeneity caused by different scanners or studied populations in multiple sites, (2) curse of dimensionality caused by millions of voxels in each fMRI scan and a very limited number (tens or hundreds) of training samples, and (3) poor interpretability, which hinders the identification of reproducible disease biomarkers. To this end, we propose a Multi-site Clustering and Nested Feature Extraction (MC-NFE) method for fMRI-based ASD detection. Specifically, we first divide multi-site training data into ASD and healthy control (HC) groups. To model inter-site heterogeneity within each category, we use a similarity-driven multiview linear reconstruction model to learn latent representations and perform subject clustering within each group. We then design a nested singular value decomposition (SVD) method to mitigate inter-site heterogeneity and extract FC features by learning both local cluster-shared features across sites within each category and global category-shared features across ASD and HC groups, followed by a linear support vector machine (SVM) for ASD detection. Experimental results on 609 subjects with rs-fMRI from the ABIDE database with 21 imaging sites suggest that the proposed MC-NFE outperforms several state-of-the-art methods in ASD detection. The most discriminative FCs identified by the MC-NFE are mainly located in default mode network, salience network, and cerebellum region, which could be used as potential biomarkers for fMRI-based ASD analysis.  相似文献   
26.
ObjectiveTo investigate whether the dance therapy was more beneficial than non-dance therapy on cognitive and mood symptoms in patients with Parkinson's disease (PD).MethodsMEDLINE, CINAHL, Embase and the Cochrane Central Register of Controlled Trials were searched from inception to December 11, 2018. Risk of bias for the included trials was assessed using criteria in the Cochrane Handbook for Systematic Reviews of Interventions.ResultsSeven randomized controlled trials were identified on cognitive and mood symptoms in patients with PD. There were significant differences in favor of dance in executive function (WMD = 1.17, 95% CI:0.39 to 1.95, P = 0.003; I2 = 0%, P = 0.45), but not in outcomes of global cognitive function, depression and apathy.ConclusionsDance therapy is beneficial in improving executive function for adults with PD. However, there are no positive effects were founded on global cognitive function, depression and apathy for PD.  相似文献   
27.
Baicalein (5,6,7-trihydroxyflavone), isolated from the root of traditional Chinese herb Scutellaria baicalensis Georgi, has anti-inflammatory and anti-oxidative activities. This study explored the protective and modulatory mechanisms of baicalein on neuroinflammation, oxidative stress and metabolic abnormality in lipopolysaccharide (LPS)-activated BV-2 cells. Our results demonstrated that treatment with baicalein remarkably restrained the production of pro-inflammatory factors including nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in LPS-activated BV-2 cells. Moreover, baicalein significantly inhibited reactive oxygen species (ROS) production, decreased cyclooxygenase-2 (COX-2) and nuclear factor-b (NF-κB)/p65 expression. 1H NMR metabolomics analysis revealed that 12 differential metabolites were regulated by baicalein, implicated in alanine, aspartate and glutamate metabolism, glutathione metabolism, arginine and proline metabolism, D-glutamine and D-glutamate metabolism. In conclusion, these results indicated that baicalein has protective and modulatory effects on neuroinflammation and oxidative stress in LPS-activated BV-2 cells.  相似文献   
28.
29.
30.
《Vaccine》2018,36(8):1108-1115
Avian hepatitis E virus (aHEV) is a pathogen associated with hepatitis-splenomegaly syndrome in chickens. To date, no commercial vaccine is available for preventing aHEV infection. In this study, three recombinant LactococcuslactisNZ9000experimental live vaccines expressing cytoplasmic, secreted, and cell wall-anchored forms of aHEV truncated ORF2 protein spanning amino acids 249–606 (ΔORF2) were constructed using pTX8048 vector and characterized. Each chicken was immunized three times at two-week intervals with one of the three live aHEV ORF2 vaccines (experimental group) or with live vaccine containing empty vector only (control group). Both groups were then challenged with aHEV and evaluated to compare immune responses and immunogenic effects. Serum IgG levels, secretory IgA (sIgA) levels in bile and jejunal lavage fluid, and mRNA expression levels ofIL-2 and IFN-γ in liver and spleen were significantly higher in experimental chickens than in controls. Meanwhile, post-challenge serum and fecal virus loads were significantly lower in experimental chickens versus controls. Moreover, on day 7 post infection (PI), serum lactose dehydrogenase (LDH) levels were significantly higher in controls than experimental chickens. Furthermore, at day 28 PI, obvious gross pathological lesions and histopathological changes typical for aHEV infection were observed in control livers and spleens, with only moderate pathological changes observed in the experimental group. The results of this study collectively demonstrate that an oral vaccineusing L.lactisNZ9000 as a delivery vector for aHEV immunogenic antigen could effectively control aHEV infection of chickens.  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