全文获取类型
收费全文 | 15662篇 |
免费 | 794篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 364篇 |
儿科学 | 517篇 |
妇产科学 | 330篇 |
基础医学 | 2589篇 |
口腔科学 | 443篇 |
临床医学 | 1400篇 |
内科学 | 2691篇 |
皮肤病学 | 357篇 |
神经病学 | 1340篇 |
特种医学 | 770篇 |
外国民族医学 | 3篇 |
外科学 | 2170篇 |
综合类 | 110篇 |
一般理论 | 11篇 |
预防医学 | 874篇 |
眼科学 | 622篇 |
药学 | 1017篇 |
中国医学 | 91篇 |
肿瘤学 | 788篇 |
出版年
2021年 | 139篇 |
2020年 | 121篇 |
2019年 | 200篇 |
2018年 | 232篇 |
2017年 | 200篇 |
2016年 | 237篇 |
2015年 | 291篇 |
2014年 | 333篇 |
2013年 | 507篇 |
2012年 | 661篇 |
2011年 | 746篇 |
2010年 | 462篇 |
2009年 | 412篇 |
2008年 | 684篇 |
2007年 | 702篇 |
2006年 | 728篇 |
2005年 | 695篇 |
2004年 | 689篇 |
2003年 | 674篇 |
2002年 | 557篇 |
2001年 | 510篇 |
2000年 | 451篇 |
1999年 | 414篇 |
1998年 | 205篇 |
1997年 | 144篇 |
1996年 | 134篇 |
1995年 | 130篇 |
1994年 | 119篇 |
1993年 | 86篇 |
1992年 | 226篇 |
1991年 | 205篇 |
1990年 | 219篇 |
1989年 | 201篇 |
1988年 | 191篇 |
1987年 | 173篇 |
1986年 | 153篇 |
1985年 | 169篇 |
1984年 | 118篇 |
1983年 | 110篇 |
1982年 | 84篇 |
1980年 | 71篇 |
1979年 | 118篇 |
1978年 | 98篇 |
1977年 | 111篇 |
1975年 | 89篇 |
1974年 | 79篇 |
1973年 | 78篇 |
1972年 | 98篇 |
1971年 | 79篇 |
1938年 | 77篇 |
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
1.
Bioimpedance as a measure of fluids in patients with septic shock. A prospective observational study
Janne Meisner Madsen Theis S. Itenov Ellen Bjerre Koch Morten H. Bestle 《Acta anaesthesiologica Scandinavica》2023,67(3):319-328
Background
Septic shock is often treated with aggressive fluid resuscitation leading to profound fluid overload. The assessment of fluid status relies on suboptimal measures making treatment difficult. Bioelectrical impedance analysis is an alternative but the validity is unclear. The aim of this study was to determine the validity of bioelectrical impedance analysis for fluid measures in patients with septic shock.Methods
Single-center, prospective observational cohort study. We included adult ICU patients with septic shock. We evaluated the agreement between measures on the left and right side of the patient and measures 1 h apart by two bioelectrical impedance devices. Results are presented as Bland Altman plots with 95% Limits of Agreements (LoA) and as correlations between bioelectrical impedance analysis results and clinical markers of fluids.Results
Forty-nine patients were included. The agreement between measures on the left and the right side of the patient and after 1 h was overall without bias, but with wide LoA's. Fluid overload 1 h apart showed the most narrow 95% LoA (−2.4–2.9 L). The same wide limits of agreements were observed when comparing devices. For example, total body water with 95% LoA of −14.8 –16.7 L. Correlations between bioelectrical impedance analysis and clinical measures were low but statistically significant.Conclusions
In patients with septic shock bioelectrical impedance analysis had no systematic errors or bias, but wide limits of agreement, indicating that the devices have a large and uncorrectable random error. Fluid status by bioelectrical impedance analysis is not sufficiently accurate to guide treatment in this group of patients. 相似文献2.
Tobias Hüppe Sascha Kreuer Hinnerk Wulf Dennik Freitag Martin Seidel Tobias Teucke Felix Maurer Andreas Kirschbaum Tilo Koch Frank Langer Thomas Volk Carsten Feldmann 《Acta anaesthesiologica Scandinavica》2023,67(4):455-461
Background
Volatile propofol can be measured in exhaled air and correlates to plasma concentrations with a time delay. However, the effect of single-lung ventilation on exhaled propofol is unclear. Therefore, our goal was to evaluate exhaled propofol concentrations during single-lung compared to double-lung ventilation using double-lumen tubes.Methods
In a first step, we quantified adhesion of volatile propofol to the inner surface of double-lumen tubes during double- and single-lumen ventilation in vitro. In a second step, we enrolled 30 patients scheduled for lung surgery in two study centers. Anesthesia was provided with propofol and remifentanil. We utilized left-sided double-lumen tubes to separately ventilate each lung. Exhaled propofol concentrations were measured at 1-min intervals and plasma for propofol analyses was sampled every 20 min. To eliminate the influence of dosing on volatile propofol concentration, exhalation rate was normalized to plasma concentration.Results
In-vitro ventilation of double-lumen tubes resulted in increasing propofol concentrations at the distal end of the tube over time. In vitro clamping the bronchial lumen led to an even more pronounced increase (Δ AUC +62%) in propofol gas concentration over time. Normalized propofol exhalation during lung surgery was 31% higher during single-lung compared to double-lung ventilation.Conclusion
During single-lung ventilation, propofol concentration in exhaled air, in contrast to our expectations, increased by approximately one third. However, this observation might not be affected by change in perfusion-ventilation during single-lung ventilation but rather arises from reduced propofol absorption on the inner surface area of the double-lumen tube. Thus, it is only possible to utilize exhaled propofol concentration to a limited extent during single-lung ventilation.Registration of Clinical Trial
DRKS-ID DRKS00014788 ( www.drks.de ). 相似文献3.
Schröer-Günther Milly Koch Klaus 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》2022,65(5):559-566
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Um Menschen eine informierte Entscheidung über die Teilnahme an Krebsfrüherkennungsuntersuchungen zu ermöglichen,... 相似文献
4.
Monika Kasper-Sonnenberg Holger M. Koch Petra Apel Maria Rüther Claudia Pälmke Thomas Brüning Marike Kolossa-Gehring 《International journal of hygiene and environmental health》2019,222(8):1084-1092
DINCH (cyclohexane-1,2-dicarboxylic acid-diisononyl ester) is a phthalate plasticizer substitute introduced into the market in 2002. It is increasingly used especially in the production of toys, food contact materials and medical devices. In this measurement campaign on 24-h urine samples of young adults (20–29 years) from the German Environmental Specimen Bank (ESB) collected in 2010, 2011, 2013, 2015 and 2017 (in total 300 samples, 60 samples/year) we analyzed three specific, oxidized DINCH metabolites (OH-MINCH: cyclohexane-1,2-dicarboxylic acid-mono(hydroxy-isononyl) ester; cx-MINCH: cyclohexane-1,2-dicarboxylic acid-mono(carboxy-isooctyl) ester, oxo-MINCH: cyclohexane-1,2-dicarboxylic acid-mono(oxo-isononyl) ester). We merged these data with earlier data of the ESB from the years 1999–2012 and are now able to report levels and time trends of internal DINCH exposure from 1999 to 2017.After first detections of the major oxidized DINCH metabolite OH-MINCH in 2006 (6.7%) detection rates rapidly increased to 43.3% in 2009, 80% in 2010 and 98.3% in 2011 and 2012. From the year 2013 on we could detect OH-MINCH in every urine sample analyzed. The median concentrations of OH-MINCH rapidly increased from 0.15 μg/L in 2010 to twice the concentration in 2011 (0.31 μg/L) with further increases in 2013 (0.37 μg/L), 2015 (0.59 μg/L) and 2017 (0.70 μg/L). Similar increases, albeit at lower detection rates and concentration levels, could be observed for cx-MINCH and oxo-MINCH. All metabolites strongly correlate with each other.For the ESB study population, DINCH exposures are still far below health based guidance values such as the German Human Biomonitoring Value (HBM-I; 4,500 μg/L for the sum of OH-MINCH and cx-MINCH) or the tolerable daily intake (TDI) of EFSA (1 mg/kg bw/d). The median daily DINCH intake (DI) calculated for 2017 was 0.23 μg/kg bw/d, thus 4,310-times lower than the TDI. The maximum DI calculated for one individual in 2012 (42.60 μg/kg bw/d) was a factor of more than 20 below the TDI.The ongoing increase in DINCH exposure needs to be closely monitored in the future, including populations with potentially higher exposures such as children. This close monitoring will enable timely exposure and risk reduction measures if exposures reached critical levels, or if new toxicological data lead to lower health based guidance values. DINCH belongs to the European Human Biomonitoring Initiative (HBM4EU) priority substances for which policy relevant questions still have to be answered. 相似文献
5.
Pietro Nenoff Shyam B. Verma Resham Vasani Anke Burmester Uta‐Christina Hipler Franziska Wittig Constanze Krüger Kolja Nenoff Cornelia Wiegand Abir Saraswat Rengarajan Madhu Saumya Panda Anupam Das Mahendra Kura Akshay Jain Daniela Koch Yvonne Grser Silke Uhrlaß 《Mycoses》2019,62(4):336-356
The disease burden of chronic‐relapsing and therapy‐refractory superficial dermatophytosis dramatically increased in India within the past 5‐6 years. In order to evaluate the prevalence of this trend, 201 skin scrapings were collected from patients from all parts of India and were tested for dermatophytes using both fungal culture and a PCR‐ELISA directly performed with native skin scrapings. Fungal culture material was identified by genomic Sanger sequencing of the internal transcribed spacer (ITS) region and the translation elongation factor (TEF)‐1α gene. In total, 149 (74.13%) out of the 201 samples showed a dermatophyte‐positive culture result. Out of this, 138 (92.62%) samples were identified as Trichophyton (T.) mentagrophytes and 11 (7.38%) as Trichophyton rubrum. The PCR‐ELISA revealed similar results: 162 out of 201 (80.56%) samples were dermatophyte‐positive showing 151 (93.21%) T mentagrophytes‐ and 11 (6.79%) T rubrum‐positive samples. In this study, we show for the first time a dramatic Indian‐wide switch from T rubrum to T mentagrophytes. Additionally, sequencing revealed a solely occurring T mentagrophytes “Indian ITS genotype” that might be disseminated Indian‐wide due to the widespread abuse of topical clobetasol and other steroid molecules mixed with antifungal and antibacterial agents. 相似文献
6.
Der Freie Zahnarzt - 相似文献
7.
8.
Oliver Sartor MD Daniel Heinrich MD Neil Mariados MD Maria José Méndez Vidal MD Daniel Keizman MD Camilla Thellenberg Karlsson MD Avivit Peer MD Giuseppe Procopio MD Stephen J. Frank MD Kalevi Pulkkanen MD Eli Rosenbaum MD Stefano Severi MD José Trigo MD Lucia Trandafir MD Volker Wagner MD Rui Li MS Luke T. Nordquist MD 《The Prostate》2019,79(14):1683-1691
9.
Der Freie Zahnarzt - 相似文献
10.