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   2432篇
  免费   109篇
  国内免费   45篇
耳鼻咽喉   4篇
儿科学   63篇
妇产科学   13篇
基础医学   210篇
口腔科学   42篇
临床医学   192篇
内科学   251篇
皮肤病学   97篇
神经病学   62篇
特种医学   59篇
外科学   153篇
综合类   269篇
预防医学   120篇
眼科学   26篇
药学   854篇
  3篇
中国医学   115篇
肿瘤学   53篇
  2023年   30篇
  2022年   38篇
  2021年   69篇
  2020年   124篇
  2019年   82篇
  2018年   61篇
  2017年   72篇
  2016年   66篇
  2015年   57篇
  2014年   116篇
  2013年   185篇
  2012年   144篇
  2011年   163篇
  2010年   104篇
  2009年   121篇
  2008年   104篇
  2007年   110篇
  2006年   86篇
  2005年   84篇
  2004年   56篇
  2003年   72篇
  2002年   66篇
  2001年   47篇
  2000年   45篇
  1999年   24篇
  1998年   27篇
  1997年   23篇
  1996年   24篇
  1995年   20篇
  1994年   17篇
  1993年   21篇
  1992年   12篇
  1991年   17篇
  1990年   19篇
  1989年   15篇
  1988年   10篇
  1987年   18篇
  1986年   18篇
  1985年   18篇
  1984年   33篇
  1983年   29篇
  1982年   26篇
  1981年   24篇
  1980年   25篇
  1979年   17篇
  1978年   13篇
  1977年   6篇
  1976年   8篇
  1974年   4篇
  1967年   3篇
排序方式: 共有2586条查询结果,搜索用时 15 毫秒
1.
The purpose of this pilot project was to evaluate the efficacy of the Collaborative Integrated Laboratory Reports (CLIR) postanalytical tools from Mayo Clinic for detection of newborns with proximal urea cycle disorders (PUCD) in the Georgia newborn screening program that uses the underivatized Neobase2 kit (Perkin Elmer). We evaluated 138,560 newborn screening (NBS) samples (between 125,000 and 130,000 children) and used the CLIR result interpretation guidelines to stratify results. Children at higher risk of having a PUCD received follow-up services including confirmatory lab testing (ammonia, plasma amino acids, urine orotic acid) or a repeat NBS sample. We made multiple adjustments to our CLIR PUCD tool and to our follow-up algorithms in order to reduce false positives. Regardless, a high number of NBS samples resulted with false positives in part due to the glutamine peak also containing lysine. No children were diagnosed with a PUCD during our study period, and the Emory Genetics Metabolic Center is unaware of any children diagnosed outside of the NBS system during that time. Based on our experience, PUCD is not suitable for statewide NBS using Neobase2 and CLIR. Other methodologies that can separate glutamine from other amino acids may have better performance.  相似文献   
2.
Teicoplanin formulations are marketed as antibiotic mixtures with several compounds that share the same core structure. Recent studies conducted in vitro have reported differences in the composition ratio of different teicoplanin products. In this retrospective study, we examined the trough blood concentration of the originator brand and a generic teicoplanin product. Target patients were retrospectively assigned to the originator (Targocid) or generic group. The groups were matched 1:1 using propensity scores. The initial trough blood concentration analysis identified 44 matches. In both groups, the median dosing day for the first measurements was 4, respectively. The initial trough blood concentration of the originator group was significantly higher (mean ± SD, 16.3 ± 4.5 mg/L) than that of the generic group (12.8 ± 4.7 mg/L; 95% CI, ?5.4 to ?1.6). A significant difference was observed in the frequency of serum creatinine elevation in the study of the frequency of adverse events using Common Terminology Criteria for Adverse Events (originator group, 41.9% vs generic group, 20.9%). In cases where discontinuation was necessary due to side effects, there were three patients in the originator group and one patient in the generic group. This study found that trough blood concentration differed between formulations. Therefore, correction might be necessary while monitoring drug concentration in the blood. Trough blood concentrations are used as surrogate markers for efficacy and safety, so further studies on differences in efficacy and safety between formulations are required.  相似文献   
3.
4.
目的建立东北苦菜Ixeris vesicolor DC.UPLC指纹图谱,并进行化学模式识别。方法东北苦菜甲醇提取物的分析采用CORTECS C18色谱柱(2.1 mm×150 mm,1.6μm);流动相0.1%磷酸水⁃乙腈,梯度洗脱;体积流量0.1 mL/min;检测波长(1~15 min,327 nm;15~50 min,360 nm);柱温35℃;进样量2μL。采用相似度分析和化学模式识别技术相结合的方法对其进行质量评价。结果10批样品指纹图谱中有19个共有峰,相似度均大于0.953。通过聚类分析将样品分成2类,主成分分析结果支持聚类分析结果,采用正交偏最小二乘法⁃判别分析筛选出了导致不同批次药材质量差异的3个共有峰,指认出2号峰(绿原酸)和12号峰(木犀草素)。结论该方法稳定可靠,可系统、全面地评价东北苦菜的药材质量。  相似文献   
5.
6.
疱疹性咽峡炎(herpangina,HA)与手足口病(hand-foot-mouth disease,HFMD)均是由肠道病毒感染引起的急性传染性疾病,在许多方面都有相似之处。首先,二者感染源高度重合,且不同地区流行株之间VP1区域序列无明显差异,同源性较高。其次,二者流行特征有许多相似之处:均以夏季多发、易感人群均为低年龄段婴幼儿。同时在临床表现与预后方面,两者也有一定的相关性:HA临床表现为咽峡与软腭处的疱疹及溃疡,伴有发热、喉痛与食欲减退,预后较好;HFMD临床表现为口腔颊、舌黏膜处溃疡,与手部、足部、膝部与臀部的特征性水疱,可出现重症型。一方面,虽然多数HA具有自限性且预后良好,但有文献表明具有特定临床表现如腹泻、呕吐、肢体抖动、嗜睡的HA有可能进展为HFMD,另一方面,早期出现的HA是重症HFMD的危险因素,重症HFMD甚至仅表现为口腔咽峡部疱疹。医护人员应重视对HA临床表现的观察,尽早识别潜在的HFMD患儿,防止其进一步发展或转化。  相似文献   
7.
目的探讨川芎⁃天麻配伍对川芎中川芎嗪、阿魏酸在大鼠脑内药动学的影响。方法18只大鼠随机分成川芎组、川芎⁃天麻(1∶0.25)组、川芎⁃天麻(1∶1)组,每组6只,建立血瘀型偏头痛模型。灌胃给药后,于大鼠脑内插入微透析探针,收集不同时间点脑透析液,UPLC⁃MS/MS法检测川芎嗪、阿魏酸含有量,绘制血药浓度⁃时间曲线,计算药动学参数。结果与单味药组比较,配伍组2种成分T1/2[川芎⁃天麻(1∶1)组阿魏酸除外]、MRT0~∞、Cmax、AUC0~∞升高(P<0.05,P<0.01);川芎⁃天麻(1∶0.25)组两者T1/2、MRT0~∞、AUC0~∞高于川芎⁃天麻(1∶1)组(P<0.05,P<0.01),川芎嗪Cmax降低(P<0.05)。结论天麻可提高川芎中川芎嗪、阿魏酸脑组织吸收程度,延长作用时间,减缓消除速率,增加蓄积,其作用强度与天麻剂量有关。  相似文献   
8.
Although 12 g/day sulbactam/ampicillin (SBT/ABPC) is approved in Japan, differences in the frequency of adverse effects induced by conventional (≤6 g/day) and high (≥9 g/day) doses remain unclear. We performed a retrospective observational study on SBT/ABPC-treated hospitalized adult patients with pneumonia from October 2015 to January 2018 to compare the safety between high and low doses. Patients were divided into high-dose (≥9 g/day, n = 200) and low-dose (≤6 g/day, n = 246) groups. We used logistic regression to determine propensity scores for the high-dose and low-dose groups and compared the incidence of adverse effects after propensity score adjustment (n = 200 in each group). Following propensity score adjustment, the frequency of elevated alanine aminotransferase (ALT) level was still significantly higher in the high-dose group than in the low-dose group (21% versus 11%, p = 0.006). In contrast, the frequencies of elevated alkaline phosphatase, aspartate aminotransferase, and serum creatinine levels and decreased white blood cell and platelet counts, and incidence of anemia, were not. Changes in blood urea nitrogen levels, erythrocyte count, and hematocrit were not significantly different between the two dose groups. There were two cases of rash reported to the Pharmaceuticals and Medical Devices Agency as an adverse effect in the high-dose group. Thirty-day mortality rates were not significantly different after propensity score adjustment. Our analysis suggests that an increase in the ALT grade was more frequent in patients treated with a daily dose of SBT/ABPC of ≥9 g.  相似文献   
9.
目的考察柴葛芩连汤联合常规治疗对湿热闭肺型小儿支气管肺炎患者的临床疗效。方法 137例患者随机分为对照组(68例)和观察组(69例),对照组给予常规治疗(吸氧、布洛芬、头孢美唑钠、喜炎平注射液),观察组在对照组基础上加用柴葛芩连汤,疗程10 d。检测临床疗效、恢复情况、血清炎症因子(CRP、IL-6、IL-8、TNF-α)、中医证候评分变化。结果观察组总有效率高于对照组(P<0.05),恢复情况(除X线全胸片消失时间外)更明显(P<0.05)。治疗后,2组炎症因子水平、中医证候评分降低(P<0.05),以观察组更明显(P<0.05)。结论柴葛芩连汤可缓解湿热闭肺型小儿支气管肺炎患者症状,其机制可能与下调血清CRP、IL-6、IL-8、TNF-α水平有关。  相似文献   
10.
ABSTRACT

Tryptophan (Trp) is not only a nutrient enhancer but also has systemic effects. Trp metabolites signaling through the well-known aryl hydrocarbon receptor (AhR) constitute the interface of microbiome-gut-brain axis. However, the pathway through which Trp metabolites affect central nervous system (CNS) function have not been fully elucidated. AhR participates in a broad variety of physiological and pathological processes that also highly relevant to intestinal homeostasis and CNS diseases. Via the AhR-dependent mechanism, Trp metabolites connect bidirectional signaling between the gut microbiome and the brain, mediated via immune, metabolic, and neural (vagal) signaling mechanisms, with downstream effects on behavior and CNS function. These findings shed light on the complex Trp regulation of microbiome-gut-brain axis and add another facet to our understanding that dietary Trp is expected to be a promising noninvasive approach for alleviating systemic diseases.  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