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   3370篇
  免费   364篇
  国内免费   261篇
耳鼻咽喉   48篇
儿科学   26篇
妇产科学   34篇
基础医学   163篇
口腔科学   74篇
临床医学   372篇
内科学   509篇
皮肤病学   67篇
神经病学   165篇
特种医学   93篇
外国民族医学   1篇
外科学   464篇
综合类   936篇
预防医学   139篇
眼科学   58篇
药学   164篇
  7篇
中国医学   498篇
肿瘤学   177篇
  2024年   4篇
  2023年   130篇
  2022年   156篇
  2021年   285篇
  2020年   237篇
  2019年   109篇
  2018年   119篇
  2017年   61篇
  2016年   120篇
  2015年   160篇
  2014年   266篇
  2013年   189篇
  2012年   290篇
  2011年   323篇
  2010年   250篇
  2009年   158篇
  2008年   159篇
  2007年   195篇
  2006年   157篇
  2005年   148篇
  2004年   114篇
  2003年   101篇
  2002年   57篇
  2001年   28篇
  2000年   21篇
  1999年   24篇
  1998年   25篇
  1997年   8篇
  1996年   6篇
  1995年   9篇
  1994年   7篇
  1993年   3篇
  1992年   13篇
  1991年   21篇
  1990年   28篇
  1989年   6篇
  1988年   1篇
  1987年   6篇
  1986年   1篇
排序方式: 共有3995条查询结果,搜索用时 15 毫秒
1.
Obsessive-compulsive disorder (OCD) is a type of hereditary mental illness, which seriously affect the normal life of the patients. Sparse learning has been widely used in detecting brain diseases objectively by removing redundant information and retaining monitor valuable biological characteristics from the brain functional connectivity network (BFCN). However, most existing methods ignore the relationship between brain regions in each subject. To solve this problem, this paper proposes a spatial similarity-aware learning (SSL) model to build BFCNs. Specifically, we embrace the spatial relationship between adjacent or bilaterally symmetric brain regions via a smoothing regularization term in the model. We develop a novel fused deep polynomial network (FDPN) model to further learn the powerful information and attempt to solve the problem of curse of dimensionality using BFCN features. In the FDPN model, we stack a multi-layer deep polynomial network (DPN) and integrate the features from multiple output layers via the weighting mechanism. In this way, the FDPN method not only can identify the high-level informative features of BFCN but also can solve the problem of curse of dimensionality. A novel framework is proposed to detect OCD and unaffected first-degree relatives (UFDRs), which combines deep learning and traditional machine learning methods. We validate our algorithm in the resting-state functional magnetic resonance imaging (rs-fMRI) dataset collected by the local hospital and achieve promising performance.  相似文献   
2.
3.
4.
目的探讨脊髓小脑共济失调2型(SCA2)致病基因ATXN2异常等位基因中间重复个体的表型和分子遗传学特点。方法针对2005—2018年中日友好医院神经科运动障碍与神经遗传病研究中心收集的1383个常染色体显性遗传共济失调家系的先证者和部分家系成员,采用荧光标记毛细管电泳片段分析方法进行动态突变检测,对携带ATXN2基因中间重复的个体进行临床表型和遗传特征分析。结果共检出163个家系(包含先证者和家系成员共203人)携带异常扩展的ATXN2基因CAG重复序列,其中93个家系中有107例的异常扩展等位基因重复次数在29~34次之间。在其中的20个亲子对中,父系遗传16个,异常等位基因的代间扩展增加0~28次,母系遗传4个,异常等位基因的代间扩展增加0~4次。结论对于临床拟诊SCA2家系患者,需对其亲代或成年子代个体进行ATXN2基因检测,以免漏诊。动态突变基因检测有助于识别中间重复的个体,对明确家系致病基因和遗传咨询至关重要。  相似文献   
5.
This meta-analysis was designed to assess the effectiveness and safety of extracorporeal shock wave therapy (ESWT) for patients with low back pain (LBP). Pubmed, Embase, Cochrane's library, PEDro (Physiotherapy Evidence Database), China National Knowledge Infrastructure (CNKI), and Wanfang Data were searched until December 2019 to identify studies assessing the effectiveness and safety of EPSW for LBP. The prime outcome is pain intensity measured by Visual Analog Scale (VAS) or numeric rating scale (NRS). Other outcomes included functional status, quality of life, psychological outcomes measured by Oswestry Disability Index (ODI), as well as the adverse events. Mean differences (MD) were calculated for continuous outcomes, while odd ratios (OR) were calculated for binary outcomes. Revman 5.3 software was used for statistical analysis. Five randomized controlled trials (RCTs) were finally included in this meta-analysis. The pooled mean difference in post-treatment pain scores was −2.37 (P <0.0001), indicating that post-treatment pain scores was significantly higher by 2.37 in control group than in ESWT group. At a mean follow-up time of 4–6 weeks, the pooled mean difference in ODI scores was −14.10 (P <0.00001), indicating that the pooled mean difference of post-treatment ODI scores was 14.10 higher in control group than in ESWT group. The use of ESWT is effective in alleviating pain and improving the general functional state for patients with LBP. However, more evidence was needed to verify its safety.  相似文献   
6.
While pap test is the most common diagnosis methods for cervical cancer, their results are highly dependent on the ability of the cytotechnicians to detect abnormal cells on the smears using brightfield microscopy. In this paper, we propose an explainable region classifier in whole slide images that could be used by cyto-pathologists to handle efficiently these big images (100,000x100,000 pixels). We create a dataset that simulates pap smears regions and uses a loss, we call classification under regression constraint, to train an efficient region classifier (about 66.8% accuracy on severity classification, 95.2% accuracy on normal/abnormal classification and 0.870 KAPPA score). We explain how we benefit from this loss to obtain a model focused on sensitivity and, then, we show that it can be used to perform weakly supervised localization (accuracy of 80.4%) of the cell that is mostly responsible for the malignancy of regions of whole slide images. We extend our method to perform a more general detection of abnormal cells (66.1% accuracy) and ensure that at least one abnormal cell will be detected if malignancy is present. Finally, we experiment our solution on a small real clinical slide dataset, highlighting the relevance of our proposed solution, adapting it to be as easily integrated in a pathology laboratory workflow as possible, and extending it to make a slide-level prediction.  相似文献   
7.
BackgroundVenous leg ulcers (VLUs) often take a very long time to heal. Timolol maleate has been reported as displaying efficacy in healing of VLUs.ObjectivesTo evaluate the efficacy of timolol maleate gel in the management of hard-to-heal VLUs and to assess its safety as a topical agent during 12 weeks of use in combination with conventional treatment.MethodsA prospective, phase-II randomised-controlled trial with a sample size based on Fleming's one-stage design (P0 = 0.25, P1 = 0.45, alpha = 0.1, beta = 0.2) was planned. Patients with VLUs present for ≥ 24 weeks and with ≥ 50% granulation tissue were included. One drop of sustained-release timolol gel (Timoptol® LP 0.5%, Santen, Tampere, Finland) per 6 cm2 VLU area was applied every 2 days for 12 weeks in timolol-treated patients, as adjuvant therapy to the standard care protocol (interface dressing and multilayer venous compression). Controls received standard care alone. The primary endpoint was to obtain ≥ 40% reduction in ulcer area at week 12 (W12).ResultsForty-three patients were randomised to the study, with 40 receiving at least one treatment and included in the analysis: 21 timolol-treated patients and 19 controls (females: 70%; median age: 72.5 [range 35–93] years). At W12, ≥ 40% ulcer-area reduction was achieved in 14/21 (67%) timolol-treated patients vs. 6/19 (32%) controls. No serious adverse events occurred. Local wound infections not requiring systemic antibiotics occurred in 5 cases in the timolol group and in one case in the controls.ConclusionsThese results support the benefit and safety of using timolol maleate to manage hard-to-heal VLUs, but confirmation is required in a larger multicentre randomised phase-III study.  相似文献   
8.
9.
目的 观察形觉剥夺性高度近视(form deprivation high myopia,FDHM)豚鼠巩膜形态变化,探讨缺氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)及氧自由基在高度近视中的作用。方法 将豚鼠适应性饲养1周后,随机分为空白对照组(25只)和模型组(25只)。模型组豚鼠右眼行眼睑缝合,所有模型组豚鼠均选择右眼作为FDHM组,对侧眼为自身对照组。空白对照组豚鼠不做任何处理。于造模前及造模后8周采用检影镜测量屈光度,A超进行生物测量。形觉剥夺8周以后处死豚鼠,观察巩膜形态和超微结构的变化,测定巩膜HIF-1α相对表达量,超氧化物歧化酶(superoxide dismutase,SOD)活力及丙二醛(malondialdehyde,MDA)的含量。结果 豚鼠形觉剥夺8周以后,FDHM组屈光度从(+3.59±0.33)D变为(-7.96±0.55)D,明显高于空白对照组(+0.89±0.32)D、自身对照组(-0.55±0.49)D(均为P<0.05);玻璃体腔深度为(4.12±0.13)mm明显高于空白对照组(3.71±0.23)mm和自身对照组(3.93±0.04)mm(均为P<0.05);眼轴长度为(8.93±0.22)mm明显长于空白对照组(7.95±0.37)mm和自身对照组(8.01±0.15)mm(均为P<0.05)。巩膜组织明显变薄,细胞外基质增多,成纤维细胞密度降低,胶原纤维平均直径减小。FDHM组巩膜中HIF-1α相对表达量、MDA含量明显高于空白对照组和自身对照组,SOD活力明显低于空白对照组和自身对照组(均为P<0.05)。结论 形觉剥夺8周后,豚鼠FDHM眼近视度数明显增加,玻璃体腔深度增加,眼轴延长,巩膜形态发生病理性变化;HIF-1α、SOD、MDA可能参与了FDHM的形成。  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