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   8958篇
  免费   1178篇
  国内免费   79篇
耳鼻咽喉   42篇
儿科学   73篇
妇产科学   32篇
基础医学   309篇
口腔科学   6308篇
临床医学   359篇
内科学   414篇
皮肤病学   23篇
神经病学   335篇
特种医学   81篇
外科学   161篇
综合类   1006篇
现状与发展   1篇
预防医学   164篇
眼科学   48篇
药学   473篇
  6篇
中国医学   163篇
肿瘤学   217篇
  2024年   31篇
  2023年   196篇
  2022年   218篇
  2021年   378篇
  2020年   488篇
  2019年   421篇
  2018年   422篇
  2017年   438篇
  2016年   484篇
  2015年   494篇
  2014年   741篇
  2013年   634篇
  2012年   592篇
  2011年   597篇
  2010年   375篇
  2009年   342篇
  2008年   331篇
  2007年   341篇
  2006年   308篇
  2005年   253篇
  2004年   226篇
  2003年   219篇
  2002年   195篇
  2001年   162篇
  2000年   142篇
  1999年   115篇
  1998年   109篇
  1997年   92篇
  1996年   97篇
  1995年   98篇
  1994年   94篇
  1993年   73篇
  1992年   90篇
  1991年   66篇
  1990年   37篇
  1989年   49篇
  1988年   40篇
  1987年   36篇
  1986年   41篇
  1985年   18篇
  1984年   22篇
  1983年   16篇
  1982年   12篇
  1981年   17篇
  1980年   11篇
  1979年   7篇
  1978年   11篇
  1977年   9篇
  1976年   11篇
  1975年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
目的 探索黄芩素调控核苷酸结合寡聚化结构域样受体蛋白 3 ( nucleotide-binding oligomerization domain-like receptor protein 3, NLRP3) / 半胱氨酸天冬氨酸蛋白酶 1 ( cysteine aspartate protease 1, Caspase1) 通路对牙周炎大鼠牙槽骨吸收的影响。 方法 将 40 只牙周炎大鼠随机分为模型组、 黄芩素组、 激活剂 组、 黄芩素 + 激活剂组, 另取 10 只正常作为对照组。 检测大鼠釉牙骨质界到牙槽嵴顶 (CEJ-AC) 的距离、 血清中白细胞介素-6 (IL-6)、 转化生长因子-β (TGF-β) 含量以及牙周组织病理变化、 IL-6、 TGF-β 阳性 表达和 NLRP3、 Caspase-1 蛋白表达。 结果 模型组大鼠 CEJ-AC、 NLRP3、 Caspase-1、 IL-6、 TGF-β 水平及 阳性表达水平以及蛋白表达水平均升高 (P< 0. 05); 经黄芩素干预后, 各项指标均降低 (P< 0. 05); 引入 激活剂明显削弱了黄芩素对牙周炎大鼠的抗炎作用。 结论 黄芩素通过抑制 NLRP3 / Caspase-1 通路减轻炎性反应, 控制牙槽骨吸收。  相似文献   
3.
目的 慢性牙周炎表现的病理性骨吸收非常常见,牙周膜干细胞(PDLSCs)的外泌体(Exo)对骨吸收的作用和影响尚不明确,本研究分析了该Exo蛋白组分对破骨细胞分化的影响。方法 分别从正畸前拔牙患者和慢性牙周炎患者的牙周膜组织中提取PDLSCs,通过流式细胞术检测表面标记物;通过差速离心分别提取2种细胞的Exo,即Exo-WT和Exo-CP,并通过Western blot、透射电子显微镜(TEM)、蛋白浓度检测、纳米粒径追踪检测Exo特征;通过蛋白质谱检测2种Exo的蛋白组分;通过酶联免疫吸附(ELISA)验证了差异表达蛋白肿瘤坏死因子α(TNF-α)、核因子κB受体活化因子配体(RANKL)、白细胞介素(IL)-1α、转化生长因子β(TGF-β)、骨形态发生蛋白2(BMP-2)表达水平;将10、100、1 000 μg·mL-1的Exo-CP或Exo-WT加入RAW264.7培养基中并于5 d时通过实时荧光定量聚合酶链反应(RT-qPCR)、Western blot、抗酒石酸酸性磷酸酶(TRAP)染色检测破骨分化相关指标表达情况;采用SPSS 24.0软件对实验数据进行统计学分析。结果 Exo-CP富集的差异表达蛋白主要与破骨细胞分化的TNF信号通路、核转录因子κB(NF-κB)信号通路相关;ELISA实验证实了Exo-CP中高表达TNF-α、RANKL、IL-1α,低表达TGF-β1、BMP-2(P<0.05);Exo-CP作用于RAW264.7,显著提高了细胞的破骨分化相关基因及蛋白的表达水平,TRAP染色可见分化的破骨细胞,且呈现浓度依赖性,100、1 000 μg·mL-1浓度Exo-CP对破骨细胞分化的促进作用显著高于10 μg·mL-1浓度组(P<0.05)。结论 慢性牙周炎的病理性骨吸收可能由炎性PDLSCs所分泌的Exo通过促进破骨细胞分化引起,Exo中主要的作用蛋白可能为RANKL和TNF-α,本研究为慢性牙周炎骨吸收的发病机制提供了新视角。  相似文献   
4.
《Saudi Dental Journal》2022,34(7):596-603
ObjectiveStudies have shown that gingival crevices may be a significant route for SARS-CoV-2 entry. However, the role of oral health in the acquisition and severity of COVID-19 is not known.DesignA retrospective analysis was performed using electronic health record data from a large urban academic medical center between 12/1/2019 and 8/24/2020. A total of 387 COVID-19 positive cases were identified and matched 1:1 by age, sex, and race to 387 controls without COVID-19 diagnoses. Demographics, number of missing teeth and alveolar crestal height were determined from radiographs and medical/dental charts. In a subgroup of 107 cases and controls, we also examined the rate of change in alveolar crestal height. A conditional logistic regression model was utilized to assess association between alveolar crestal height and missing teeth with COVID-19 status and with hospitalization status among COVID-19 cases.ResultsIncreased alveolar bone loss, OR = 4.302 (2.510 – 7.376), fewer missing teeth, OR = 0.897 (0.835–0.965) and lack of smoking history distinguished COVID-19 cases from controls. After adjusting for time between examinations, cases with COVID-19 had greater alveolar bone loss compared to controls (0.641 ± 0.613 mm vs 0.260 ± 0.631 mm, p < 0.01.) Among cases with COVID-19, increased number of missing teeth OR = 2.1871 (1.146– 4.174) was significantly associated with hospitalization.ConclusionsAlveolar bone loss and missing teeth are positively associated with the acquisition and severity of COVID-19 disease, respectively.  相似文献   
5.
彭静山教授提出“一点二穴三线四面”八字取穴法。笔者运用此八字取穴法指导针灸临床取穴治疗难治性面瘫,临床效果显著。本文列举临床典型病例,详细阐述取穴和针刺治疗方法,并对治疗机理进行论述。对于难治性面瘫,单纯毫针针刺治疗效果有一定局限性,以“一点二穴三线四面”八字取穴法为基础,取穴点以透刺连接构成线、面,以芒针联合透刺法为主要治疗方法,可强化治疗效果、提高临床效应。  相似文献   
6.

Background

Refractory acute myeloid leukemia (AML) includes AML includes failure of disease to respond to standard induction chemotherapy, relapse within 6 months after first CR, and 2 or more relapses. The outcome of these patients is usually very poor; only a small proportion can be rescued by allogenic hematopoietic stem-cell transplantation (allo-HSCT). The aim of this study was to evaluate the efficacy and feasibility of allo-HSCT in patients with refractory AML.

Patients and Methods

We retrospectively analyzed the clinical outcome of 91 patients who were diagnosed with treatment-refractory AML at Hacettepe University Hospital between January 2002 and June 2018. Patients' disease status included refractory AML, defined as failure to respond to standard induction chemotherapy and relapse within 6 months after first complete remission.

Results

The median follow-up was 12 months (range, 0.5-184 months) for the entire group. Kaplan-Meier estimates of the 3-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 67% and 12%, respectively. Additionally, the Kaplan-Meier estimates of 5-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 44% and 4%, respectively (P < .001). Complete remission was obtained in 25 patients (83.3%) who underwent allo-HSCT; however, the disease of only 3 patients (3.8%) exhibited complete response after salvage chemotherapy.

Conclusion

Allo-HSCT is still the best-known treatment option with curative potential in patients with treatment-refractory AML. Therefore, all efforts should be made in an attempt to find a suitable matched donor in order to perform allo-HSCT.  相似文献   
7.
8.
《Clinical neurophysiology》2019,130(1):128-137
ObjectiveHigh frequency oscillations (HFO) between 80–500 Hz are markers of epileptic areas in intracranial and maybe also scalp EEG. We investigate simultaneous recordings of scalp and intracranial EEG and hypothesize that scalp HFOs provide important additional clinical information in the presurgical setting.MethodsSpikes and HFOs were visually identified in all intracranial scalp EEG channels. Analysis of correlation of event location between intracranial and scalp EEG as well as relationship between events and the SOZ and zone of surgical removal was performed.Results24 patients could be included, 23 showed spikes and 19 HFOs on scalp recordings. In 15/19 patients highest scalp HFO rate was located over the implantation side, with 13 patients having the highest scalp and intracranial HFO rate over the same region. 17 patients underwent surgery, 7 became seizure free. Patients with poor post-operative outcome showed significantly more regions with HFO than those with seizure free outcome.ConclusionsScalp HFOs are mostly located over the SOZ. Widespread scalp HFOs are indicative of a larger epileptic network and associated with poor postsurgical outcome.SignificanceAnalysis of scalp HFO add clinically important information about the extent of epileptic areas during presurgical simultaneous scalp and intracranial EEG recordings.  相似文献   
9.
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