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   1418篇
  免费   91篇
  国内免费   26篇
耳鼻咽喉   41篇
儿科学   34篇
妇产科学   11篇
基础医学   231篇
口腔科学   91篇
临床医学   87篇
内科学   294篇
皮肤病学   13篇
神经病学   57篇
特种医学   64篇
外科学   161篇
综合类   2篇
预防医学   22篇
眼科学   160篇
药学   143篇
中国医学   23篇
肿瘤学   101篇
  2023年   12篇
  2022年   27篇
  2021年   55篇
  2020年   21篇
  2019年   41篇
  2018年   44篇
  2017年   37篇
  2016年   44篇
  2015年   63篇
  2014年   75篇
  2013年   92篇
  2012年   122篇
  2011年   128篇
  2010年   80篇
  2009年   78篇
  2008年   99篇
  2007年   76篇
  2006年   74篇
  2005年   53篇
  2004年   77篇
  2003年   50篇
  2002年   52篇
  2001年   20篇
  2000年   23篇
  1999年   18篇
  1998年   10篇
  1997年   6篇
  1996年   7篇
  1995年   1篇
  1994年   2篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1989年   3篇
  1988年   4篇
  1987年   3篇
  1986年   5篇
  1985年   1篇
  1983年   2篇
  1981年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1975年   3篇
  1974年   2篇
  1964年   1篇
  1963年   2篇
  1962年   4篇
  1961年   4篇
  1960年   2篇
排序方式: 共有1535条查询结果,搜索用时 15 毫秒
61.

Background

There is no consensus on the optimal method of primary tumor control, determined by preoperative clinical factors, during sentinel node (SN) navigation surgery for early gastric cancer (EGC). In this study, we investigated the accuracy of clinical diagnosis based on preoperative examination in patients with EGC and proposed surgical options for primary tumor control during SN navigation surgery.

Methods

We analyzed 815 patients with clinical stage IA gastric cancer who underwent gastrectomy at the National Cancer Center in Korea between March 2001 and February 2011. The clinical stage was determined by endoscopy, endoscopic ultrasonography, and abdominal computed tomography.

Results

The preoperative assessment of tumor depth and tumor size was accurate in 57.5 and 70.8 % of patients, respectively. Tumor depth and size were underestimated in 8 and 25.3 % of patients. The overall accuracy of histologic diagnosis by endoscopic biopsy was 87.2 %. Of those tumors diagnosed preoperatively as differentiated, 20.5 % revealed mixed histology of undifferentiated type.

Conclusions

The recommendation for SN biopsy may be limited to tumors sized 3 cm or smaller to avoid positive lateral margins and to minimize the risk of skip metastases. Endoscopic resection may safely be applied to small mucosal cancers, but other surgical options should be employed for undifferentiated large mucosal lesions, given their tendency for diffuse invasion. Full-thickness resection is preferable for submucosal cancers, to secure clear vertical margins.  相似文献   
62.
As an alternative to animal tests for skin sensitization potency and risk assessment, cell viability and biomarkers related to skin sensitization were analyzed in THP-1 human monocytic leukemia cells. Cell viabilities of 90% (CV90) and 75% (CV75) were determined for 24 selected test chemicals. Further biomarkers related to skin sensitization were also determined under equivalent comparative conditions. In cell viability analyses, potent skin sensitizers exhibited high cytotoxicity, but non-sensitizers did not display this tendency. In biomarker analyses, interleukin-I beta (IL-1β), inducible nitric oxide synthase (iNOS), IL-1β+iNOS, and THP-1 IL-1β+Raw 264.7 IL-1β were found to be suitable for prediction of skin sensitization potency following classification as either skin sensitizers or non-sensitizers (accuracies of 91.7%, 87.5%, 83.3%, and 82.6%, respectively). A significant positive correlation was found between biomarkers and skin sensitization potency, with a correlation coefficient (R) of 0.7 or more (correlation coefficients of 0.77, 0.72, 0.7, and 0.84, respectively). Finally, the skin sensitization potency effective threefold concentration (EC) 3% was predicted using a biomarker equation, with resulting prediction rates (match rate with actual data) of 58.3%, 54.2%, 62.5%, and 60.9%, respectively. The prediction accuracy for the EC3 value obtained from animal data was calculated as 83.3%, 79.2%, 79.2%, and 73.9%, respectively. Thus, these biomarkers, IL-1β and iNOS, may be alternatively used to predict skin sensitization potency and risk assessment.  相似文献   
63.
64.
65.
Lipocalin-2 (LCN2) is a secreted protein of the lipocalin family, but little is known about the expression or the role of LCN2 in the central nervous system. Here, we investigated the role of LCN2 in ischemic stroke using a rodent model of transient cerebral ischemia. Lipocalin-2 expression was highly induced in the ischemic brain and peaked at 24 hours after reperfusion. After transient middle cerebral artery occlusion, LCN2 was predominantly expressed in astrocytes and endothelial cells, whereas its receptor (24p3R) was mainly detected in neurons, astrocytes, and endothelial cells. Brain infarct volumes, neurologic scores, blood–brain barrier (BBB) permeabilities, glial activation, and inflammatory mediator expression were significantly lower in LCN2-deficient mice than in wild-type animals. Lipocalin-2 deficiency also attenuated glial neurotoxicity in astrocyte/neuron cocultures after oxygen-glucose deprivation. Our results indicate LCN2 has a critical role in brain injury after ischemia/reperfusion, and that LCN2 may contribute to neuronal cell death in the ischemic brain by promoting neurotoxic glial activation, neuroinflammation, and BBB disruption.  相似文献   
66.
67.
Hemoglobin M (HbM) is a group of abnormal hemoglobin variants that form methemoglobin, which leads to cyanosis and hemolytic anemia. HbM-Milwaukee-2 is a rare variant caused by the point mutation CAC>TAC on codon 93 of the hemoglobin subunit beta (HBB) gene, resulting in the replacement of histidine by tyrosine. We here report the first Korean family with HbM-Milwaukee-2, whose diagnosis was confirmed by gene sequencing. A high index of suspicion for this rare Hb variant is necessary in a patient presenting with cyanosis since childhood, along with methemoglobinemia and a family history of cyanosis.  相似文献   
68.
PurposeTo assess the effect of dupilumab on the annualized severe exacerbation rates, change in forced expiratory volume at first second (FEV1), overall asthma control and health-related quality of life in Korean patients from the LIBERTY ASTHMA QUEST study.MethodsOf the 1,902 patients enrolled in the LIBERTY ASTHMA QUEST study, a phase-3, randomized, double-blind, placebo-controlled, parallel-group study on dupilumab, 74 (4%) were Korean. The patients were randomly assigned to 4 treatment groups (2:2:1:1). The sub-analysis reported herewith was performed with the pooled groups of dupilumab and placebo from the 4 original treatment groups in the LIBERTY ASTHMA QUEST study. The efficacy endpoints were annualized rate of severe exacerbation events during the 52-week study period and changes from baseline in pre-bronchodilator FEV1 in week 12. Asthma control, asthma quality of life and the effect of treatment on the levels of type 2 inflammatory biomarkers were assessed. The safety profile was also evaluated.ResultsIn Korean patients, annualized severe exacerbation rates were reduced with dupilumab (n = 49) compared to placebo (n = 25) (0.259 vs 1.942) during the 52-week treatment period. The relative risk reduction with dupilumab was 87% (P < 0.001). Improvements in pre-bronchodilator FEV1 (mean difference of 0.24 L, P = 0.021) were observed in week 12 in dupilumab-treated patients. Additionally, improvements in asthma control and asthma-related quality of life were observed; the FeNO and serum immunoglobulin E levels were reduced. The incidence of adverse events and serious adverse events was comparable between the dupilumab and placebo group. A total of 11 patients from the dupilumab group reported 63 injection site reactions.ConclusionsDupilumab, as an add-on therapy in severe asthma, is efficacious and has an acceptable safety profile in Korean patients.Trial RegistrationClinicalTrials.gov Identifier: NCT02414854  相似文献   
69.
We evaluated the genotypic origin of mesenchymal stem cells (MSC) following sex-mismatched allogeneic bone marrow transplantation (BMT), and investigated the telomere dynamics in MSC in normal individuals and patients after BMT. The study population consisted of 11 patients with hematologic disorders who showed complete chimerism after BMT. Telomere length was measured in MSC using Southern blotting analysis in eight patients and 18 healthy subjects as a control group. Following culture, MSC were identified by the expression of SH2 and SH4, and lack of CD14, CD34, and CD45. All MSC showed the recipient genotype, based on the results of fluorescent in situ hybridization analysis using X-chromosome satellite probes or microsatellite DNA polymorphism analysis. The mean telomere length in MSC from normal controls was 7.2+/-0.53 kb (range, 6.12-7.78), and progressive telomere shortening was seen with age. There was no significant difference in MSC telomere length between the BMT group and age-matched controls. This study confirmed that the MSC isolated from the recipients of allogeneic BMT did not have the donor genotype, despite complete chimerism. Moreover, MSC were demonstrated to show progressive loss of telomere length with age, but the telomeres in MSC were not affected by BMT.  相似文献   
70.
BackgroundThis study aimed to perform meta-analyses to update a previous systematic review (SR) conducted by the US Preventive Services Task Force (USPSTF) to evaluate the benefits and harms of screening for chronic obstructive pulmonary disease (COPD) in asymptomatic adults.MethodsMEDLINE, EMBASE, Cochrane Library, and regional databases were searched from their inception to January 2020. Studies for diagnostic accuracy, preventive services effect, treatment efficacy, and treatment harms were included.ResultsEighteen studies were included, and twelve of these were newly added in this update. In meta-analyses, the pooled sensitivity and specificity for COPD diagnosis using spirometry were 73.4% and 89.0%, respectively. The relative effect of smoking cessation intervention with screening spirometry, presented as abstinence rate, was not statistically significant (risk ratio [RR], 1.21; 95% confidence interval [CI], 0.87–1.67) when all selected studies were pooled, but screening on smoking cessation was effective (RR, 1.58; 95% CI, 1.14–2.19) when limited to studies with smoking cessation programs that provided smoking cessation medicines or intensive counseling at public health centers or medical institutions.ConclusionIn this study, no direct evidence for the impact on health outcomes of screening asymptomatic adults for COPD was identified similar to the previous SR. Further research is necessary to confirm the benefits of COPD screening.  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