全文获取类型
收费全文 | 18769篇 |
免费 | 2251篇 |
国内免费 | 353篇 |
专业分类
耳鼻咽喉 | 392篇 |
儿科学 | 939篇 |
妇产科学 | 1093篇 |
基础医学 | 1793篇 |
口腔科学 | 185篇 |
临床医学 | 1966篇 |
内科学 | 2678篇 |
皮肤病学 | 161篇 |
神经病学 | 868篇 |
特种医学 | 473篇 |
外国民族医学 | 3篇 |
外科学 | 1234篇 |
综合类 | 1308篇 |
现状与发展 | 2篇 |
预防医学 | 2779篇 |
眼科学 | 501篇 |
药学 | 1914篇 |
12篇 | |
中国医学 | 365篇 |
肿瘤学 | 2707篇 |
出版年
2024年 | 71篇 |
2023年 | 444篇 |
2022年 | 727篇 |
2021年 | 957篇 |
2020年 | 941篇 |
2019年 | 939篇 |
2018年 | 853篇 |
2017年 | 860篇 |
2016年 | 916篇 |
2015年 | 867篇 |
2014年 | 1324篇 |
2013年 | 1849篇 |
2012年 | 1056篇 |
2011年 | 1115篇 |
2010年 | 900篇 |
2009年 | 856篇 |
2008年 | 873篇 |
2007年 | 815篇 |
2006年 | 699篇 |
2005年 | 595篇 |
2004年 | 498篇 |
2003年 | 491篇 |
2002年 | 343篇 |
2001年 | 314篇 |
2000年 | 231篇 |
1999年 | 236篇 |
1998年 | 204篇 |
1997年 | 187篇 |
1996年 | 140篇 |
1995年 | 134篇 |
1994年 | 121篇 |
1993年 | 100篇 |
1992年 | 108篇 |
1991年 | 76篇 |
1990年 | 81篇 |
1989年 | 53篇 |
1988年 | 57篇 |
1987年 | 50篇 |
1986年 | 41篇 |
1985年 | 55篇 |
1984年 | 36篇 |
1983年 | 30篇 |
1982年 | 29篇 |
1981年 | 27篇 |
1980年 | 16篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Rapid and simple LC‐MS/MS screening of 64 novel psychoactive substances using dried blood spots
下载免费PDF全文
![点击此处可从《Drug testing and analysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The range of novel psychoactive substances (NPS) including phenethylamines, cathinones, piperazines, tryptamines, etc. is continuously growing. Therefore, fast and reliable screening methods for these compounds are essential and needed. The use of dried blood spots (DBS) for a fast straightforward approach helps to simplify and shorten sample preparation significantly. DBS were produced from 10 µl of whole blood and extracted offline with 500 µl methanol followed by evaporation and reconstitution in mobile phase. Reversed‐phase chromatographic separation and mass spectrometric detection (RP‐LC‐MS/MS) was achieved within a run time of 10 min. The screening method was validated by evaluating the following parameters: limit of detection (LOD), matrix effect, selectivity and specificity, extraction efficiency, and short‐term and long‐term stability. Furthermore, the method was applied to authentic samples and results were compared with those obtained with a validated whole blood method used for routine analysis of NPS. LOD was between 1 and 10 ng/ml. No interference from matrix compounds was observed. The method was proven to be specific and selective for the analytes, although with limitations for 3‐FMC/flephedrone and MDDMA/MDEA. Mean extraction efficiency was 84.6 %. All substances were stable in DBS for at least a week when cooled. Cooling was essential for the stability of cathinones. Prepared samples were stable for at least 3 days. Comparison to the validated whole blood method yielded similar results. DBS were shown to be useful in developing a rapid screening method for NPS with simplified sample preparation. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
992.
993.
Renate Krüger Ulrich Baumann Stephan Borte Uwe Kölsch Myriam Ricarda Lorenz Baerbel Keller Ina Harder Klaus Warnatz Stephan Ehl Klaus Schwarz Volker Wahn Horst von Bernuth 《Scandinavian journal of immunology》2020,91(1):e12811
Hypomorphic mutations in the gene encoding Bruton tyrosine kinase (BTK) may result in milder phenotypes and delayed diagnosis of B-cell related immunodeficiencies due to residual BTK function. Newborn screening for kappa-deleting-recombination-excision circles (KRECs) reliably identifies classical X-linked agammaglobulinaemia (XLA) patients with profound B-cell lymphopenia at birth but has not been evaluated in patients with residual BTK function. We aimed to evaluate clinical findings, BTK function and KREC copy numbers in three patients with BTK mutations presenting with impaired polysaccharide responsiveness without agammaglobulinaemia. One patient had an invasive pneumococcal infection at the age of 4 years. All three patients (two brothers) had visible tonsils, normal to slightly decreased immunoglobulin G levels, undetectable pneumococcal antibodies despite pneumococcal conjugate vaccinations, no antibody response after a diagnostic polysaccharide vaccination as well as profound B-cell lymphopenia with residual B-cell differentiation. BTK mutations were identified by Sanger sequencing. BTK staining and phosphorylation assays were performed on peripheral B cells. KREC copy numbers were determined from dried blood spots obtained within the first week of life as well as once at the age of 8, 6 and 3 years, respectively. BTK staining showed residual protein expression. Also, residual BTK activity could be demonstrated. KREC copy numbers from dried blood spots were above the threshold set for detection of patients with profound B-cell lymphopenia. Male patients with impaired polysaccharide responsiveness should be evaluated for B-cell lymphopenia followed by BTK analyses irrespective of immunoglobulin levels or tonsil size. 相似文献
994.
目的确定东莞地区耳聋基因的变异类型和携带率。方法收集新生儿及门诊筛查的16182名个体,新生儿采集足跟血片,非新生儿采集外周静脉血样,对18个耳聋易感基因的100种变异进行检测。结果共检出1631例耳聋基因变异,总体检出率为10.08%,其中5例为纯合变异。SLC26A4基因变异的检出率最高(5.22%),共845例,其余依次为GJB2(673例,4.16%)、GJB3(100例,0.62%)、TMC1(12例,0.07%)、MYO15A(1例,0.01%)。GJB2基因c.235delC变异检出率最高(3.24%),共524例,其次为SLC26A4基因IVS7-2A>G变异(270例,1.67%)。33名个体(0.20%)同时携带两个变异,其中7例(0.04%)携带同一基因的复合杂合变异。结论扩大耳聋易感基因变异的筛查范围有助于了解携带情况及耳聋的遗传因素,对提早发现先天性耳聋、对受检者提供干预和遗传咨询具有重要的价值。 相似文献
995.
苯丙酮尿症为常染色体隐性遗传病,是常见的氨基酸代谢异常之一,在中国的平均发病率约为1/11000,表现为南方地区低、北方(尤其是西北地区)高的特征。苯丙酮尿症是可以治疗的遗传病,被列为中国新生儿筛查疾病之一。经筛查确诊的新生儿通过及时控制苯丙氨酸的摄人可以达到满意的治疗效果。本指南旨在总结关于苯丙酮尿症的医学遗传学知识和临床处置要点,以提高临床人员对该病的诊断水平、规范开展新生儿筛査,对患者临床管理的规范化提供建议。 相似文献
996.
Acceptance and utilization of HIV testing among the youth: a cross-sectional study in Techiman,Ghana
BackgroundIn Ghana, efforts including ‘Know Your Status’ campaign have been made to increase awareness and improve the uptake of HIV screening.ObjectiveThis study examined the acceptance and utilization of the HIV/AIDS ‘Know Your Status’ campaign and determine dthe differences in HIV testing by demographic characteristics among the youth in Techiman, Ghana.MethodThis study was a cross-sectional study conducted among the youth aged 15–24 years. A structured questionnaire was used to collect data from 200 purposively selected respondents.ResultsThe mean age of the respondents was 19.6±2.72 years. There was a universal awareness (100%) of HIV/AIDs, and were knowledgeable about the mode of transmission, symptoms and the prevention of HIV. A high proportion of the respondents (n=161, 80.5%) had heard about the ‘Know Your Status’ (KYS) campaign. Less than half of respondents (n=91, 45.5%) had tested for HIV, and only 16.5% (n=15/91) of respondents tested through the KYS campaign. Testing for HIV was associated with age (p<0.001) and marital status (p<0.001).ConclusionThe youth should therefore be targeted in the awareness and the ‘Know Your Status campaigns’, and in an effortsto promote screening for HIV. 相似文献
997.
998.
Cervical cancer screening by cytology and human papillomavirus testing during pregnancy in french women with poor adhesion to regular cervical screening
下载免费PDF全文
![点击此处可从《Journal of medical virology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
999.
1000.
Herman Depypere Joelle Desreux Faustino R. Pérez-López Iuliana Ceausu C. Tamer Erel Irene Lambrinoudaki Karin Schenck-Gustafsson Yvonne T. van der Schouw Tommaso Simoncini Florence Tremollieres Margaret Rees 《Maturitas》2014