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   6038篇
  免费   465篇
  国内免费   137篇
耳鼻咽喉   2篇
儿科学   215篇
妇产科学   75篇
基础医学   426篇
口腔科学   117篇
临床医学   842篇
内科学   458篇
皮肤病学   34篇
神经病学   126篇
特种医学   103篇
外科学   583篇
综合类   1146篇
预防医学   807篇
眼科学   26篇
药学   1022篇
  8篇
中国医学   477篇
肿瘤学   173篇
  2023年   56篇
  2022年   77篇
  2021年   212篇
  2020年   207篇
  2019年   184篇
  2018年   185篇
  2017年   172篇
  2016年   211篇
  2015年   215篇
  2014年   358篇
  2013年   446篇
  2012年   407篇
  2011年   375篇
  2010年   301篇
  2009年   229篇
  2008年   280篇
  2007年   274篇
  2006年   241篇
  2005年   234篇
  2004年   208篇
  2003年   194篇
  2002年   146篇
  2001年   130篇
  2000年   101篇
  1999年   82篇
  1998年   84篇
  1997年   65篇
  1996年   64篇
  1995年   69篇
  1994年   77篇
  1993年   57篇
  1992年   58篇
  1991年   63篇
  1990年   66篇
  1989年   52篇
  1988年   47篇
  1987年   33篇
  1986年   27篇
  1985年   58篇
  1984年   46篇
  1983年   31篇
  1982年   43篇
  1981年   27篇
  1980年   19篇
  1979年   19篇
  1978年   19篇
  1977年   17篇
  1976年   12篇
  1974年   11篇
  1973年   13篇
排序方式: 共有6640条查询结果,搜索用时 31 毫秒
1.
ObjectiveTo examine the screening rates for kidney damage and function among patients with type 2 diabetes (T2D) and chronic kidney disease stage at diabetes diagnosis using a US administrative claims database.Patients and MethodsThis cohort study used a claims database enriched with laboratory results data. Patients with T2D (defined as 1 inpatient or 2 outpatient claims for diabetes), aged 18 years or older, and with at least 1 year of follow-up enrollment were identified. Patients with type 1 diabetes, kidney disease, or other related conditions at baseline were excluded. We estimated screening rates using laboratory orders for serum creatinine and estimated glomerular filtration rate (eGFR) measurement and urine albumin to creatinine ratio (UACR). Chronic kidney disease severity was reported using the Kidney Disease: Improving Global Outcomes classification based on laboratory results.ResultsA total of 1,881,447 patients with T2D were eligible for analysis. Mean ± SD age was 63.1±13.1 years; 947,150 patients (50.3%) were male. Serum creatinine tests were ordered within 14 days of the index date among 290,722 patients of 622,915 (46.7%) patients with newly-recognized T2D. Overall, 1,595,964 patients (84.8%) had at least one serum creatinine test ordered during the 1-year follow-up period. Fewer patients received a UACR test during follow-up (814,897 [43.3%]). Less than half of all patients with T2D received a laboratory test order for both serum creatinine and urine albumin measurements during the follow-up period.ConclusionPhysicians treating patients with diabetes are selectively adhering to chronic kidney disease screening guidelines, as indicated by high rates of eGFR testing, but less frequent UACR testing. Despite recommendations to monitor both eGFR and UACR, less than half of patients were screened for albuminuria during the 1-year follow-up.  相似文献   
2.
BackgroundIn 2021, the National Salt and Sugar Reduction Initiative (NSSRI) released voluntary sugar reduction targets for packaged foods and drinks in the United States.ObjectiveThe objectives of this study were to describe trends in added sugar intake from NSSRI foods and beverages among children and youth and estimate possible reductions if industry were to meet the targets.DesignThis study consisted of cross-sectional and trend analyses of demographic and 24-hour dietary recall data from eight survey cycles (2003-2004 to 2017-2018) of the National Health and Nutrition Examination Survey.Participants/settingThe study sample included 23,248 children and youth (aged 2 to 19 years).Main outcome measuresThe main outcome measure was the percent of daily calories from added sugar for foods and beverages in NSSRI categories.Statistical analyses performedFoods and beverages reported by participants were mapped to one of the NSSRI’s categories or coded as a non-NSSRI item. Trends over time in added sugar intake were assessed using regression models. To assess possible reductions in added sugar intake if industry were to meet the targets, sales-weighted mean percent reductions for 2023 and 2026 targets were applied to NSSRI items in the 2017-2018 National Health and Nutrition Examination Suvey data. Results were examined overall and by demographic characteristics.ResultsFrom 2003-2004 to 2017-2018, added sugar intake from NSSRI foods and beverages declined, but consumption remained high. During 2017-2018, NSSRI categories accounted for 70% of US child and youth added sugar intake. If industry met the NSSRI targets, US children and youth would consume 7% (2023 targets) to 21% (2026 targets) less added sugar.ConclusionsAlthough added sugar intake from NSSRI foods and drinks has declined over the past decade, added sugar intake from all sources remains high and consumption of added sugar from certain NSSRI categories has remained steady over time. If met, the NSSRI targets are expected to result in meaningful reductions in added sugar intake for US children and youth.  相似文献   
3.
Biomarker discovery has been increasingly important in the field of metabolomics for the detection and understanding of diseases. Of the many biofluids available for metabolomics, urine is a preferred option as it is non-invasive to collect and contains a wide range of metabolites reflective of the health status of the testing individual. However, urine also contains many exogenous metabolites which are introduced through various sources such as diet. This complicates the data interpretation when searching the metabolome for disease-related endogenous metabolites. Since diet is difficult to control, this work aims to study the acute effects of diet (particularly cow milk) consumption on the human urine amine/phenol submetabolome by utilizing differential chemical isotope labeling (CIL) liquid chromatography mass spectrometry (LC-MS). LC-MS analysis of 62 urine samples collected before and after (1 hour and 2 hours) milk intake resulted in the detection of 4985 metabolites with an average of 3815 ± 206 (n = 62) detected per sample. The work aims to differentiate the exogenous “food” metabolites from the endogenous metabolite pool and to determine any dietary effects from milk intake on the human urine metabolome.  相似文献   
4.
钟艳麟  谭永娟  雷雯媛 《全科护理》2020,18(11):1376-1377
[目的]观察改良式女婴集尿袋收集尿液标本的临床应用效果。[方法]将300例新生儿女婴随机分为试验组和对照组各150例,试验组采用改良式集尿袋收集尿标本,对照组采用传统集尿袋收集尿标本,分别比较两组收集尿液标本一次成功率及受大便污染率。[结果]试验组收集尿液标本一次成功率为79.3%明显高于对照组60.7%,试验组尿液标本受大便污染率为4.7%低于对照组12.7%(P均<0.05)。[结论]改良式女婴集尿袋的使用能明显提高留取尿液标本的一次成功率,同时降低受大便污染率。  相似文献   
5.
目的:探讨玉液汤对2型糖尿病肥胖患者肠道菌群及脂质代谢影响。方法:选取2017年2月至2019年2月广州市中医医院收治的2型糖尿病肥胖患者106例作为研究对象,按照就诊顺序分为对照组和观察组,每组53例。2组均给予基础治疗+药物治疗,观察组再加用玉液汤治疗。观察2组治疗前、完成治疗后肠道菌群、脂质代谢、中医症状积分、血糖相关指标、体质量、腰围、体质量指数(BMI)变化并比较。结果:2组治疗前各指标比较差异无统计学意义(P>0.05),完成治疗后观察组患者的中医症状积分、FINS、HOMA-IR、HbAlc、BMI、腰围、体质量、TC、TG、LDL-C、肠杆菌、酵母菌、肠球菌、畏寒肢冷、腰膝酸软、脘腹2组患者治疗后HDL-C、双岐杆菌、乳杆菌、拟杆菌均较治疗后明显上升,且观察组高于对照组(P<0.05)。结论:玉液汤能改善2型糖尿病肥胖患者脂质代谢和临床症状,降低血糖,能调节肠道菌群紊乱,从而提高疗效。  相似文献   
6.
目的:对急性痛风性关节炎大鼠给予穿山龙提取物后的尿液代谢组学进行研究,寻找相关的潜在生物标志物及相关代谢通路。方法:采用尿酸钠(MSU)诱导的急性痛风性关节炎大鼠模型,将SD大鼠40只随机分为空白组、穿山龙提取物组、模型组、穿山龙提取物干预组,每组10只。给药组灌胃给予穿山龙提取物,给药剂量0. 48 g·kg~(-1),每天1次,连续5 d,于末次给药后,收集大鼠尿液,运用UPLC-Q-TOF/MS结合模式识别方法分析,采用正、负离子扫描模式下电喷雾离子源,数据采集范围m/z 100~1 500,采用全扫描方式。结果:鉴别出了12个共同的潜在生物标志物,分别为肌氨酸,二甲基甘氨酸,脱氧胞苷,尿酸,5-HT,L-胱硫醚,4-吡哆酸,脱氧尿苷,褪黑激素,5-甲氧基色胺,富马酸和胞苷。与空白组比较,穿山龙提取物组中这12个潜在生物标志物均明显下调;与模型组比较,在穿山龙提取物干预组的潜在生物标志物中,有10个上调,2个下调,穿山龙提取物对肌氨酸,尿酸,L-胱硫醚,4-吡哆酸,脱氧尿苷,5-甲氧基色胺,胞苷,二甲基甘氨酸,褪黑激素,富马酸这10个标志物均表现出了纠正异常表达的趋势;与急性痛风性关节炎相关性最强的代谢通路为半胱氨酸和甲硫氨酸代谢、色氨酸代谢。结论:穿山龙提取物可能是通过促进半胱氨酸和甲硫氨酸代谢中胱硫醚向半胱氨酸的转化水平,上调色氨酸代谢中褪黑激素,实现对痛风性关节炎的防治作用。  相似文献   
7.
8.
目的:探析2型糖尿病患者采取参芪降糖颗粒联合二甲双胍进行治疗的降糖效果。方法:选取2016年1月至2019年10月马鞍山市中心医院收治的2型糖尿病患者66例作为研究对象,按照随机数字表法分为对照组与观察组,每组33例,对照组通过二甲双胍进行治疗,观察组通过二甲双胍联合参芪降糖颗粒进行治疗,比较2组患者治疗总有效率、血糖参数、不良反应发生率等指标。结果:对照组、观察组的治疗总有效分别为75.76%、93.94%,与对照组比较,观察组的治疗总有效率明显较高(P<0.05);观察组的空腹血糖、餐后2 h血糖等血糖参数在治疗后明显低于对照组患者(P<0.05);对照组、观察组的治疗不良反应发生率分别为21.21%、3.03%,观察组治疗不良反应发生率明显低于对照组(P<0.05)。结论:2型糖尿病患者采取参芪降糖颗粒联合二甲双胍进行治疗能够获得较为理想的效果,可明显改善血糖指标,安全性较高,对改善患者的治疗预后有着促进的作用。  相似文献   
9.
Renal cell carcinoma (RCC) is frequently diagnosed incidentally as an early-stage small renal mass (SRM; pT1a, ≤4 cm). Overtreatment of patients with benign or clinically indolent SRMs is increasingly common and has resulted in a recent shift in treatment recommendations. There are currently no available biomarkers that can accurately predict clinical behavior. Therefore, we set out to identify early biomarkers of RCC progression. We employed a quantitative label-free liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) proteomics approach and targeted parallel-reaction monitoring to identify and validate early, noninvasive urinary biomarkers for RCC-SRMs. In total, we evaluated 115 urine samples, including 33 renal oncocytoma (≤4 cm) cases, 30 progressive and 26 nonprogressive clear cell RCC (ccRCC)-SRM cases, in addition to 26 healthy controls. We identified six proteins, which displayed significantly elevated expression in clear cell RCC-SRMs (ccRCC-SRMs) relative to healthy controls. Proteins C12ORF49 and EHD4 showed significantly elevated expression in ccRCC-SRMs compared to renal oncocytoma (≤4 cm). Additionally, proteins EPS8L2, CHMP2A, PDCD6IP, CNDP2 and CEACAM1 displayed significantly elevated expression in progressive relative to nonprogressive ccRCC-SRMs. A two-protein signature (EPS8L2 and CCT6A) showed significant discriminatory ability (areas under the curve: 0.81, 95% CI: 0.70–0.93) in distinguishing progressive from nonprogressive ccRCC-SRMs. Patients (Stage I–IV) with EPS8L2 and CCT6A mRNA alterations showed significantly shorter overall survival (p = 1.407 × 10−6) compared to patients with no alterations. Our in-depth proteomic analysis identified novel biomarkers for early-stage RCC-SRMs. Pretreatment characterization of urinary proteins may provide insight into early RCC progression and could potentially help assign patients to appropriate management strategies.  相似文献   
10.
We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa’s environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly.  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