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   54501篇
  免费   4522篇
  国内免费   1310篇
耳鼻咽喉   485篇
儿科学   911篇
妇产科学   407篇
基础医学   3636篇
口腔科学   671篇
临床医学   9522篇
内科学   5366篇
皮肤病学   198篇
神经病学   7723篇
特种医学   16472篇
外国民族医学   12篇
外科学   4167篇
综合类   5168篇
现状与发展   1篇
一般理论   1篇
预防医学   879篇
眼科学   441篇
药学   1892篇
  14篇
中国医学   346篇
肿瘤学   2021篇
  2024年   91篇
  2023年   738篇
  2022年   1428篇
  2021年   2263篇
  2020年   2060篇
  2019年   1911篇
  2018年   1860篇
  2017年   2069篇
  2016年   2166篇
  2015年   2055篇
  2014年   3674篇
  2013年   3219篇
  2012年   3091篇
  2011年   3475篇
  2010年   2994篇
  2009年   3015篇
  2008年   3007篇
  2007年   2805篇
  2006年   2540篇
  2005年   2382篇
  2004年   1898篇
  2003年   1507篇
  2002年   1148篇
  2001年   1100篇
  2000年   960篇
  1999年   764篇
  1998年   732篇
  1997年   681篇
  1996年   671篇
  1995年   564篇
  1994年   509篇
  1993年   400篇
  1992年   369篇
  1991年   296篇
  1990年   246篇
  1989年   206篇
  1988年   209篇
  1987年   152篇
  1986年   92篇
  1985年   127篇
  1984年   78篇
  1983年   50篇
  1982年   69篇
  1981年   71篇
  1980年   74篇
  1979年   75篇
  1978年   86篇
  1977年   70篇
  1973年   45篇
  1972年   43篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
1.
2.
PurposeTo investigate the safety and efficacy of thyroid artery embolization (TAE) in the treatment of nodular goiter (NG).MethodsDuring a 5.5-year period, 56 consecutive patients with a NG underwent TAE. In Group A, there were 20 patients with a solitary/dominant 5–11-cm nodule, and in Group B, there were 36 patients with numerous nodules. Of the 56 patients, 47 (84%) had a retrosternal goiter and 25 had hyperthyroidism. In all patients, clinical and radiological evaluations were made at baseline and 6 months after TAE, and these parameters were statistically compared.ResultsIn 56 patients, 145 of the 146 thyroid arteries were successfully embolized. The 30-day mortality rate was 1.8%. Minor and major complications occurred in 25 and 2 patients, respectively. Six months after the TAE, the mean nodule volume was reduced from 80.2 mL to 25.0 mL, the mean thyroid volume was reduced from 147.0 mL to 62.6 mL, and the mean intrathoracic extension was reduced from 31.7 mm to 15.9 mm (P < .001). Of the 22 patients with non–Graves hyperthyroidism, 19 (86%) became euthyroid. The mean thyroid-related patient-reported outcome scores improved from 155.4 to 70.4 (P < .001). Of the 51 patients, 50 (98%) declared that they would recommend TAE to other patients with NG.ConclusionsTAE is safe and effective for the treatment of NG, with a significant volume reduction of the nodule(s) and thyroid gland.  相似文献   
3.
PurposeTo investigate the safety and efficacy of an aqueous polyethylene glycol-based liquid embolic agent, Embrace Hydrogel Embolic System (HES), in the treatment of benign and malignant hypervascular tumors.Materials and MethodsA prospective, single-arm, multicenter study included 8 patients, 5 males and 3 females, with a median age of 58.5 years (30–85 years), who underwent embolization in 8 tumors between October 2019 and May 2020. Technical success was defined as successful delivery of HES to the index vessel, with disappearance of >90% of the targeted vascular enhancement or, for portal vein embolization, occlusion of the portal branches to the liver segments for future resection. The volume of HES administered, ease of use (5 point Likert scale), administration time, and adverse events (AEs) were recorded. Evaluation was performed at 7, 30, and 90 days via clinical assessment and blood testing, and follow-up imaging was performed at 30 days.ResultsEight patients were enrolled, and 10 embolizations were performed in 8 lesions. Tumors included hepatocellular carcinoma (n = 4), renal angiomyolipoma (n = 3), and intrahepatic cholangiocarcinoma (n = 1). Technical success was 100%, and the average ease of use was 3.3 ± 1.0 SD. The HES delivery time was 1–28 minutes (median, 16.5 minutes), and the HES volume injected was 0.4–4.0 mL (median, 1.3 mL). All patients reached 30-day follow-up with imaging, and 6 patients reached 90-day follow-up. There were 3 serious AEs in 2 patients that were unrelated to the embolic agent.ConclusionHES resulted in a 100% embolization technical success rate. The product ease of use was acceptable, and no target vessel recanalization was noted on follow-up imaging at 30 days.  相似文献   
4.
《Pancreatology》2022,22(8):1175-1180
BackgroundHepatic steatosis has been described as a common finding in adults following total pancreatectomy with islet autotransplantation (TPIAT) but it is unknown if this occurs in children and adolescents.ObjectivesTo define the frequency of post-TPIAT hepatic steatosis in a sample of children and adolescents and to identify clinical predictors of incident steatosis post-TPIAT.MethodsIn this prospective study, consecutive participants at least 1-month post-TPIAT underwent a liver MRI with proton density fat fraction (PDFF) and blood draw at our pediatric academic medical center between April 2021 and January 2022. Comparison clinical pre-TPIAT liver MRI or ultrasound and insulin use and graft function data were extracted from the medical record. T-tests were used for the comparison of means across continuous variables between participants with and without post-TPIAT steatosis.ResultsA total of 20 participants (mean: 13 ± 4 years; 12 female) were evaluated. Mean liver PDFF at research MRI was 7.4 ± 6.2% (range: 2–25%). Seven participants (35%) had categorical hepatic steatosis (PDFF>5%) post-TPIAT, five of whom had pre-TPIAT steatosis, reflecting a 13% (2/15; 95% CI: 2–40%) incidence of post-TPIAT steatosis. Participant characteristics were not significantly different between subgroups with and without post-TPIAT steatosis. Mean PDFF at research MRI was not different between graft function subgroups (7.5% optimal/good vs. 7.3% marginal/failure; p = .96).ConclusionOur study shows a moderate prevalence but low incidence of hepatic steatosis in a small sample of children and adolescents post-TPIAT. This study raises questions about a causal relationship between TPIAT and hepatic steatosis.  相似文献   
5.
Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100?nm) and their implications on intestinal epithelial permeability in vitro. Au NPs aggregated in fasted gastric fluids and generated hydroxyl radicals in the presence of H2O2. Cell studies showed that GIT fluids incubation of Au NPs affected the cellular uptake of Au NPs but did not induce cytotoxicity or disturb the intestinal epithelial permeability.  相似文献   
6.
7.
目的 探讨不同年龄阿尔茨海默病(AD)患者ADC值与年龄的相关性。方法 选取30例AD患者(AD组)和年龄与之相匹配的30名志愿者(对照组),按年龄段各分为6个亚组[55~59岁(n=3)、60~64岁(n=4)、65~70岁(n=9)、71~74岁(n=5)、75~80岁(n=6)、>80岁(n=3)],测量双侧海马、红核、尾状核、杏仁体、壳核ADC值,并进行配对t检验、独立样本t检验、单因素方差分析及Pearson相关分析。结果 AD组红核左、右侧ADC值有统计学差异(P=0.022)。AD组不同年龄亚组右侧海马、双侧尾状核、右侧壳核ADC值差异有统计学意义(P均<0.05);2组不同年龄亚组双侧海马、壳核、尾状核ADC值差异有统计学意义(P均<0.05)。AD组右侧海马(r=0.615,P<0.001)、右侧壳核(r=0.653,P=0.001)及双侧尾状核(左侧:r=0.397,P=0.030;右侧:r=0.429,P=0.020)ADC值与年龄呈正相关。结论 AD患者右侧海马和壳核、双侧尾状核ADC值随年龄增加而增大。ADC值可为临床预测和早期诊断AD脑内右侧海马和壳核、双侧尾状核神经退行性病变提供参考。  相似文献   
8.
BACKGROUND Postoperative liver failure is the most severe complication in cirrhotic patients with hepatocellular carcinoma(HCC) after major hepatectomy. Current available clinical indexes predicting postoperative residual liver function are not sufficiently accurate.AIM To determine a radiomics model based on preoperative gadoxetic acid-enhanced magnetic resonance imaging for predicting liver failure in cirrhotic patients with HCC after major hepatectomy.METHODS For this retrospective study, a radiomics-based model was developed based on preoperative hepatobiliary phase gadoxetic acid-enhanced magnetic resonance images in 101 patients with HCC between June 2012 and June 2018. Sixty-one radiomic features were extracted from hepatobiliary phase images and selected by the least absolute shrinkage and selection operator method to construct a radiomics signature. A clinical prediction model, and radiomics-based model incorporating significant clinical indexes and radiomics signature were built using multivariable logistic regression analysis. The integrated radiomics-based model was presented as a radiomics nomogram. The performances of clinical prediction model, radiomics signature, and radiomics-based model for predicting post-operative liver failure were determined using receiver operating characteristics curve, calibration curve, and decision curve analyses.RESULTS Five radiomics features from hepatobiliary phase images were selected to construct the radiomics signature. The clinical prediction model, radiomics signature, and radiomics-based model incorporating indocyanine green clearance rate at 15 min and radiomics signature showed favorable performance for predicting postoperative liver failure(area under the curve: 0.809-0.894). The radiomics-based model achieved the highest performance for predicting liver failure(area under the curve: 0.894; 95%CI: 0.823-0.964). The integrated discrimination improvement analysis showed a significant improvement in the accuracy of liver failure prediction when radiomics signature was added to the clinical prediction model(integrated discrimination improvement = 0.117, P =0.002). The calibration curve and an insignificant Hosmer-Lemeshow test statistic(P = 0.841) demonstrated good calibration of the radiomics-based model. The decision curve analysis showed that patients would benefit more from a radiomics-based prediction model than from a clinical prediction model and radiomics signature alone.CONCLUSION A radiomics-based model of preoperative gadoxetic acid–enhanced MRI can be used to predict liver failure in cirrhotic patients with HCC after major hepatectomy.  相似文献   
9.
10.
癫痫作为多种病因引起的神经系统慢性、发作性疾病,严重影响着患者的生活质量,因此对其及时诊断和早期治疗极为重要。目前已有多种神经影像技术用于癫痫的定位、定侧和病理生理研究。弥散张量成像是利用水分子在组织中弥散的各向异性成像的磁共振技术,是目前唯一能在活体中无创性地显示脑白质纤维束的方法,它能敏感地显示脑部细微结构,并能揭示各个结构间的功能联系,有助于癫痫的研究。本文主要从癫痫的病因诊断、癫痫手术的辅助指导、癫痫的结构网络及其与癫病功能障碍的相关性研究等方面对DTI应用于癫痫的最新研究进展进行综述。  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