全文获取类型
收费全文 | 30161篇 |
免费 | 3102篇 |
国内免费 | 913篇 |
专业分类
耳鼻咽喉 | 241篇 |
儿科学 | 1341篇 |
妇产科学 | 419篇 |
基础医学 | 4793篇 |
口腔科学 | 684篇 |
临床医学 | 3051篇 |
内科学 | 4609篇 |
皮肤病学 | 556篇 |
神经病学 | 2439篇 |
特种医学 | 385篇 |
外国民族医学 | 6篇 |
外科学 | 1572篇 |
综合类 | 3392篇 |
现状与发展 | 7篇 |
预防医学 | 5121篇 |
眼科学 | 481篇 |
药学 | 1368篇 |
30篇 | |
中国医学 | 412篇 |
肿瘤学 | 3269篇 |
出版年
2024年 | 39篇 |
2023年 | 544篇 |
2022年 | 734篇 |
2021年 | 1359篇 |
2020年 | 1380篇 |
2019年 | 1310篇 |
2018年 | 1163篇 |
2017年 | 1237篇 |
2016年 | 1232篇 |
2015年 | 1257篇 |
2014年 | 1972篇 |
2013年 | 2314篇 |
2012年 | 1766篇 |
2011年 | 1876篇 |
2010年 | 1473篇 |
2009年 | 1599篇 |
2008年 | 1658篇 |
2007年 | 1556篇 |
2006年 | 1350篇 |
2005年 | 1172篇 |
2004年 | 1048篇 |
2003年 | 936篇 |
2002年 | 791篇 |
2001年 | 717篇 |
2000年 | 554篇 |
1999年 | 473篇 |
1998年 | 395篇 |
1997年 | 322篇 |
1996年 | 237篇 |
1995年 | 319篇 |
1994年 | 228篇 |
1993年 | 188篇 |
1992年 | 143篇 |
1991年 | 137篇 |
1990年 | 95篇 |
1989年 | 92篇 |
1988年 | 80篇 |
1987年 | 50篇 |
1986年 | 40篇 |
1985年 | 76篇 |
1984年 | 49篇 |
1983年 | 33篇 |
1982年 | 38篇 |
1981年 | 34篇 |
1980年 | 27篇 |
1979年 | 22篇 |
1978年 | 15篇 |
1977年 | 12篇 |
1976年 | 10篇 |
1970年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
101.
背景 在人口老龄化日益加剧的社会背景之下,家庭养老功能不断减弱,机构养老成为今后发展的必然趋势。据报道,很多养老机构的老年人营养不合理,严重影响老年人的健康状况与生活质量。目的 通过调查北京市养老机构老年人营养现状及其影响因素,为全科医师营养教育及老年人生活质量提升提供理论依据。方法 2014年10月-2015年12月,采用方便整群抽样的方法,抽取了北京市7家养老机构,对符合纳入标准的老年人进行面对面问卷调查,问卷内容包括:一般情况、微型营养评定量表(MNA)、日常生活活动能力指数(BI)、老年人抑郁量表(GDS)。采用二元Logistic回归分析养老机构老年人营养状况的影响因素。结果 本研究共发放问卷258份,回收有效问卷258份,有效回收率为100%。被调查的258例老年人中,存在营养不良及存在营养不良发生风险的老年人共计75例(29.1%)。不同年龄、性别、婚姻状况、体质指数(BMI)、医疗费用支付方式、生活自理能力及精神状态的老年人营养状况比较,差异有统计学意义(P<0.05)。二元Logistic回归分析结果显示:年龄〔OR(95%CI)=2.349(1.070,5.156)〕、BMI〔OR(95%CI)=0.092(0.036,0.239)〕、医疗费用支付方式〔OR(95%CI)=0.208(0.083,0.522)〕、日常活动能力〔OR(95%CI)=10.214(3.099,33.669)〕、患病种数〔OR(95%CI)=2.682(1.248,5.763)〕及精神状态〔OR(95%CI)=4.822(2.005,11.600)〕是老年人营养状况的影响因素(P<0.05)。结论 北京地区养老机构的老年人面临着营养不良及营养不良发生风险的健康威胁,高龄、低BMI、抑郁、合并多种疾病、日常活动能力低下及无医保是其独立危险因素,需要对老年人加强个性化营养教育和营养治疗。 相似文献
102.
Tong Yan Fang Junyan Deng Hai Song Ahui Zhu Tongying Ge Xiaolin Liu Yingli 《中华肾脏病杂志》2020,36(7):503-511
Objective To compare the expression level of exosomal miR-503 in peritoneal dialysis effluent (PDE) from patients of different peritoneal transport characteristics, predict the target genes of miR-503 and provide bioinformatic data for researches of peritoneal transport characteristics. Methods Twenty-four stable peritoneal dialysis (PD) patients were selected and divided into high transport group (H group, n=12) and low transport group (L group, n=12) according to the results of peritoneal equilibration tests (PET). The 500 ml PDE that was left on the patient's abdomen overnight was collected and concentrated using ultrafiltration cell. Exosomes in PDE were resuspended in phosphate buffered saline (PBS) after ultracentrifugation and the characteristics of PDE exosomes were identified by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA), Western blotting and fluorescent staining. MicroRNAs were extracted from PDE exosomes. The expression levels of PDE exosomal miR-503 in the two groups were detected by quantitative real-time PCR. Then the relations between the relative quantity of PDE exosomal miR-503 and PET values or 24 h ultrafiltration volume (UF) were analyzed. Targetscan and miRDB databases were used to predict the target genes of miR-503. Gene ontology (GO) functional enrichment and Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway analysis were relied on DAVID (https://david.ncifcrf.gov/). Results The exosomes in PDE showed a round and cup-shaped morphology under TEM, and the diameters were approximately 100 nm measured by NTA. The specific biomarkers of exosomes, CD63, CD81 and heat shock protein -70 (HSP-70) were all detected by Western blotting. The internalization and uptake of the exosomes was observed after fluorescent staining. The relative expression level of PDE exosomal miR-503 in H group was found to be significantly higher than that in L group (P=0.002), and the relative quantity of PDE exosomal miR-503 was significantly positively correlated with PET values (r=0.547, P=0.006), but not 24 h UF (r=-0.297, P=0.159). There were 156 target genes of miR-503 in total that could be predicted by two different databases at the same time. GO analysis of these 156 target genes was mainly focused on kinase binding, regulation of protein modification and catabolic process as well as regulation of epithelial cell proliferation. KEGG enriched many tumor associated or classical signaling pathways, including transforming growth factor-β (TGF-β) signaling pathway and vascular endothelial growth factor (VEGF) signaling pathway. The prediction showed that vascular endothelial growth factor A (VEGFA) was a direct target gene of miR-503 and it was also related to many proteins involved in fibrosis mechanism. Conclusions The expression level of PDE exosomal miR-503 is significantly higher in H group, and positively correlates with PET values, which may regulate the angiogenesis of peritoneal vessels by targeting VEGFA. 相似文献
103.
104.
Patients with non‐small cell lung cancer (NSCLC) containing ROS1 fusions can have a marked response to the ROS1‐targeted tyrosine kinase inhibitors (TKIs), such as crizotinib. Common resistance mechanisms of ROS1‐fusion targeted therapy are acquired mutations in ROS1. Along with the use of next‐generation sequencing in the clinical management of patients with NSCLC during sequential targeted therapy, many mechanisms of acquired resistance have been discovered in patients with activated tyrosine kinase receptors. Besides acquired resistance mutations, bypass mechanisms of resistance to epidermal growth factor receptor (EGFR)‐TKI treatment are common in patients with EGFR mutations. Here we describe a patient with metastatic lung adenocarcinoma with CD74‐ROS1 fusion who initially responded to crizotinib and then developed resistance by the acquired mutation of D1228N in the MET kinase domain, which showed short‐term disease control for cabozantinib.Key Points
- The D1228N point mutation of MET is an acquired mutation for crizotinib resistance.
- The patient obtained short‐term clinical benefit from cabozantinib therapy after resistance to crizotinib.
- The clinical use of next‐generation sequencing could maximize the benefits of precision medicine in patients with cancer.
105.
106.
Shubing Cai Susan C. Miller Ira B. Wilson 《Journal of the American Medical Directors Association》2019,20(4):497-502
Objective(s)
To examine the change in physical functional status among persons living with HIV (PLWH) in nursing homes (NHs) and how change varies with age and dementia.Design
Retrospective cohort study.Setting
NHs in 14 states in the United States.Participants
PLWH who were admitted to NHs between 2001 and 2010 and had stays of ≥90 days (N = 3550).Measurements
We linked Medicaid Analytic eXtract (MAX) and Minimum Data Set (MDS) data for NH residents in the sampled states and years and used them to determine HIV infection. The main outcome was improvement in physical functional status, defined as a decrease of at least 4 points in the activities of daily living (ADL) score within 90 days of NH admission. Independent variables of interest were age and dementia (Alzheimer's disease or other dementia). Multivariate logistic regression was used, adjusting for individual-level covariates.Results
The average age on NH admission of PLWH was 58. Dementia prevalence ranged from 14.5% in the youngest age group (age <40 years) to 38.9% in the oldest group (age ≥70 years). Overall, 44% of the PLWH experienced ADL improvement in NHs. Controlling for covariates, dementia was related to a significantly lower likelihood of ADL improvement among PLWH in the oldest age group only: the adjusted probability of improvement was 40.6% among those without dementia and 29.3% among those with dementia (P < .01).Conclusions/relevance
PLWH, especially younger persons, may be able to improve their ADL function after being admitted into NHs. However, with older age, PLWH with dementia are more physically dependent and vulnerable to deterioration of physical functioning in NHs. More and/or specialized care may be needed to maintain physical functioning among this population. Findings from this study provide NHs with information on care needs of PLWH and inform future research on developing interventions to improve care for PLWH in NHs. 相似文献107.
目的:探讨血必净注射液治疗急诊重症监护室(EICU)脓毒症患者的疗效,以及对机体炎症应激反应和心肌功能的影响。方法:采用随机数字表法将190例脓毒症分为常规组和血必净组,每组均95例。两组均严格按照脓毒症治疗指南(2016年版)给予常规抗脓毒症集束化治疗,血必净组在常规治疗基础上给予血必净注射液治疗,常规组给予等量的0.9%氯化钠注射液。观察两组治疗前和治疗7 d后急性和慢性健康状况评分系统Ⅱ(APACHE Ⅱ)评分,检测并比较治疗前后血清炎性因子肿瘤坏死因子-α(TNF-α)、超敏C-反应蛋白(hs-CRP)、降钙素原(PCT)、白介素-6(IL-6)和心肌损伤标志物血肌钙蛋白I(cTn I)、肌酸激酶同工酶(CK-MB)水平,统计两组EICU住院时间和28 d死亡率。结果:两组治疗7 d后血清TNF-α、hs-CRP、PCT、IL-6和cTn I、CK-MB水平均明显下降(P<0.05),且治疗组治疗7 d后上述炎性因子和心肌功能指标水平显著低于常规组,差异有统计学意义(P<0.05)。治疗组治疗7 d后APACHEⅡ评分明显低于常规组,EICU住院时间较常规组明显缩短,差异有统计学意义(P<0.05),两组28 d病死率比较差异无统计学意义(P>0.05)。结论:常规对症治疗联合血必净注射液能有效减轻脓毒症患者机体炎症应激反应和保护心肌功能,对改善病情程度和缩短EICU住院时间有一定价值。 相似文献
108.
目的根据现有文献,探讨新型冠状病毒肺炎的研究现状及防控措施。方法采用文献综述法。结果我国对新型冠状病毒性肺炎的生物学特性以及诊断标准和治疗方法的研究已取得重要成果,病毒的传播情况已得到了有效的遏制。结论冠状病毒虽具有较强的传染性,但采用合理的方法早发现,早诊断,早治疗,同时增强卫生健康意识,加强个人防护,及时隔离传染源,可有效控制病毒传播。 相似文献
109.
Esther M. John Amanda I. Phipps Lisa M. Hines Jocelyn Koo Sue A. Ingles Kathy B. Baumgartner Martha L. Slattery Anna H. Wu 《International journal of cancer. Journal international du cancer》2020,147(7):1808-1822
We pooled multiethnic data from four population-based studies and examined associations of menstrual and reproductive characteristics with breast cancer (BC) risk by tumor hormone receptor (HR) status [defined by estrogen receptor (ER) and progesterone receptor (PR)]. We estimated odds ratios and 95% confidence intervals using multivariable logistic regression, stratified by age (<50, ≥50 years) and ethnicity, for 5,186 HR+ (ER+ or PR+) cases, 1,365 HR− (ER− and PR−) cases and 7,480 controls. For HR+ BC, later menarche and earlier menopause were associated with lower risk in non-Hispanic whites (NHWs) and Hispanics, and higher parity and longer breast-feeding were associated with lower risk in Hispanics and Asian Americans, and suggestively in NHWs. Positive associations with later first full-term pregnancy (FTP), longer interval between menarche and first FTP and shorter time since last FTP were limited to younger Hispanics and Asian Americans. Except for nulliparity, reproductive characteristics were not associated with risk in African Americans. For HR− BC, lower risk was associated with later menarche, except in African Americans and older Asian Americans and with longer breast-feeding in Hispanics and Asian Americans only. In younger African Americans, HR− BC risk associated with higher parity (≥3 vs. 1 FTP) was increased fourfold in women who never breast-fed, but not in those with a breast-feeding history, suggesting that breast-feeding may mitigate the adverse effect of higher parity in younger African American women. Further work needs to evaluate why menstrual and reproductive risk factors vary in importance according to age and ethnicity. 相似文献
110.
Rohini KhuranaSatyajeet RathHarikesh Bahadur SinghMadhup RastogiSambit Swarup NandaAbhishek ChauhanMohammad KaifNuzhat Hussain 《Asian Pacific journal of cancer prevention》2020,21(3):755-760
Background: The standard of care in high grade glioma (HGG) is maximal safe surgical resection followed by adjuvant radiotherapy (RT) with/without chemotherapy. For anaplastic gliomas, studies have shown use of procarbazine, lomustine, vincristine (PCV) improves overall survival (OS) and progression free survival (PFS). Currently, there is substantial evidence that molecular markers strongly predict prognosis and response to treatment. Methods: Between January 2016 to January 2018, 42 patients were accrued and followed up till April 2019. The primary end points were to correlate molecular markers with response to therapy in terms of OS and PFS in HGG. The secondary end point was to evaluate frequency of 1p/19q codeletion, IDH 1 mutation, ATRX deletion and p53 in HGG patients. Results: The median age was 46 years (range 18-67) with M:F ratio 30:12. The frequency of IDH1 mutation,1p/19q codeletion, p53 mutation and ATRX mutation were 42.8%, 16.6%, 42.8% and 14.2% respectively. All the seven patients with 1p/19q codeletion had IDH1 mutation. Median follow up was 22 months. The 20-months PFS for different mutations were as follows; IDH1-mutated vs wild type: 53.6% vs 29.8%; p-0.035, 1p/19q codeleted vs non-codeleted: 85.7% vs 62.3%; p-0.011, p53 wild type vs mutated 32.1% vs 35.6%; p-0.035 and ATRX lost vs retained: 55.6% vs 53.3%; p- 0.369. The 20-months OS for IDH1 mutated vs wild type: 82.4% vs 30.6%; p-0.014, 1p/19q codeleted vs non-codeleted: 85.7% vs 65.8%; p-0.104, p53 wild-type vs mutated 45.5% vs 73.9%; p-0.036 and ATRX lost vs retained: 100% vs 60.3%; p-0.087. Conclusion: Codeletion of 1p/19q with IDH1 mutation in HGG is associated with a significantly favourable PFS. However, larger studies with longer follow up are required to evaluate OS and PFS in all the molecular subgroups. 相似文献