全文获取类型
收费全文 | 5565篇 |
免费 | 441篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 87篇 |
妇产科学 | 72篇 |
基础医学 | 1007篇 |
口腔科学 | 54篇 |
临床医学 | 580篇 |
内科学 | 1172篇 |
皮肤病学 | 149篇 |
神经病学 | 506篇 |
特种医学 | 311篇 |
外科学 | 615篇 |
综合类 | 32篇 |
一般理论 | 2篇 |
预防医学 | 331篇 |
眼科学 | 113篇 |
药学 | 414篇 |
中国医学 | 9篇 |
肿瘤学 | 481篇 |
出版年
2023年 | 26篇 |
2022年 | 37篇 |
2021年 | 133篇 |
2020年 | 64篇 |
2019年 | 113篇 |
2018年 | 133篇 |
2017年 | 117篇 |
2016年 | 155篇 |
2015年 | 196篇 |
2014年 | 206篇 |
2013年 | 265篇 |
2012年 | 370篇 |
2011年 | 439篇 |
2010年 | 244篇 |
2009年 | 286篇 |
2008年 | 427篇 |
2007年 | 386篇 |
2006年 | 417篇 |
2005年 | 381篇 |
2004年 | 412篇 |
2003年 | 353篇 |
2002年 | 295篇 |
2001年 | 66篇 |
2000年 | 47篇 |
1999年 | 49篇 |
1998年 | 58篇 |
1997年 | 50篇 |
1996年 | 27篇 |
1995年 | 31篇 |
1994年 | 27篇 |
1993年 | 22篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1982年 | 13篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 10篇 |
1977年 | 4篇 |
1975年 | 5篇 |
1974年 | 9篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有6024条查询结果,搜索用时 31 毫秒
1.
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
2.
Background The rate of preterm births in Germany is 8.6%, which is very high compared to other European countries. As preterm birth contributes significantly to perinatal morbidity and mortality rates, the existing prevention strategies need to be optimized and expanded further. About ⅔ of all women with preterm birth have preterm labor or premature rupture of membranes. They are bracketed together under the term “spontaneous preterm birth” as opposed to iatrogenic preterm birth, for example as a consequence of preeclampsia or fetal growth retardation. Recent studies suggest that low-dose aspirin does not just reduce the rate of iatrogenic preterm births but can also further reduce the rate of spontaneous preterm births. This review article presents the current state of knowledge. Method A selective literature search up until April 2020 was done in PubMed, using the terms “randomized trial”, “randomized study”, “spontaneous preterm birth”, and “aspirin”. Results Secondary analyses of prospective randomized studies on the prevention of preeclampsia with low-dose aspirin show that this intervention also significantly reduced the rate of spontaneous preterm births in both high-risk and low-risk patient populations. The results of the ASPIRIN trial, a prospective, randomized, double-blinded multicenter study carried out in six developing countries, also point in this direction, with the figures showing that the daily administration of 81 mg aspirin starting before 14 weeks of gestation lowered the preterm birth rate of nulliparous women without prior medical conditions by around 11% (11.6 vs. 13.1%; RR 0.89; 95% CI: 0.81 – 0.98, p = 0.012). Conclusion Further studies on this issue are urgently needed. If these confirm the currently available results, then it would be worth discussing whether general aspirin prophylaxis for all pregnant women starting at the latest in 12 weeks of gestation is indicated. Key words: spontaneous preterm birth, iatrogenic preterm birth, prevention, preeclampsia, aspirin 相似文献
3.
4.
Lasse Ingerslev Blaabjerg Bulut Bulduk Eleanor Lindenberg Korbinian Löbmann Thomas Rades Holger Grohganz 《Journal of pharmaceutical sciences》2019,108(8):2561-2569
In this study, the influence of the glass-forming ability (GFA) of a drug on its physical stability in a supersaturated solid dispersion was investigated. Nine drugs were classified according to their GFA using their respective critical cooling rate. Their respective solubility in poly(vinylpyrrolidone-co-vinyl acetate) 6:4 (PVPVA64) was predicted using the melting point depression method based on the Flory-Huggins lattice theory. Supersaturated amorphous solid dispersions at a level of 25% w/w drug above saturation solubility in the polymer were prepared by film-casting, and their respective physical stability at temperatures of 10°C or 20°C above or below their respective Tg (dry conditions) was monitored by the use of polarized light microscopy. This study showed that drugs with good GFA (class 3) on average have higher physical stability in supersaturated amorphous solid dispersion compared to drug with modest GFA (class 2), which in turn have higher physical stability in supersaturated amorphous solid dispersion than drugs with poor GFA (class 1). These results indicate that the GFA of a drug and its physical stability in a supersaturated amorphous solid dispersion stored at a temperature above or below its Tg are correlated. 相似文献
5.
Testing association of rare genetic variants with resistance to three common antiseizure medications
Stefan Wolking Claudia Moreau Anne T. Nies Elke Schaeffeler Mark McCormack Pauls Auce Andreja Avbersek Felicitas Becker Martin Krenn Rikke S. Møller Marina Nikanorova Yvonne G. Weber Sarah Weckhuysen Gianpiero L. Cavalleri Norman Delanty Chantal Depondt Michael R. Johnson Bobby P.C. Koeleman Wolfram S. Kunz Anthony G. Marson Josemir W. Sander Graeme J. Sills Pasquale Striano Federico Zara Fritz Zimprich Matthias Schwab Roland Krause Sanjay M. Sisodiya Patrick Cossette Simon L. Girard Holger Lerche EpiPGX Consortium 《Epilepsia》2020,61(4):657-666
6.
7.
8.
Hendrik Fritsche Thorsten Heilmann Robert J. Tower Charlotte Hauser Anja von Au Doaa El-Sheikh Graeme M. Campbell G?hkan Alp Denis Schewe Sebastian Hübner Sanjay Tiwari Daniel Kownatzki Susann Boretius Dieter Adam Walter Jonat Thomas Becker Claus C. Glüer Margot Z?ller Holger Kalthoff Christian Schem Anna Trauzold 《Oncotarget》2015,6(11):9502-9516
Despite improvements in detection, surgical approaches and systemic therapies, breast cancer remains typically incurable once distant metastases occur. High expression of TRAIL-R2 was found to be associated with poor prognostic parameters in breast cancer patients, suggesting an oncogenic function of this receptor. In the present study, we aimed to determine the impact of TRAIL-R2 on breast cancer metastasis. Using an osteotropic variant of MDA-MB-231 breast cancer cells, we examine the effects of TRAIL-R2 knockdown in vitro and in vivo. Strikingly, in addition to the reduced levels of the proliferation-promoting factor HMGA2 and corresponding inhibition of cell proliferation, knockdown of TRAIL-R2 increased the levels of E-Cadherin and decreased migration. In vivo, these cells were strongly impaired in their ability to form bone metastases after intracardiac injection. Evaluating possible underlying mechanisms revealed a strong downregulation of CXCR4, the receptor for the chemokine SDF-1 important for homing of cancers cells to the bone. In accordance, cell migration towards SDF-1 was significantly impaired by TRAIL-R2 knockdown. Conversely, overexpression of TRAIL-R2 upregulated CXCR4 levels and enhanced SDF-1-directed migration. We therefore postulate that inhibition of TRAIL-R2 expression could represent a promising therapeutic strategy leading to an effective impairment of breast cancer cell capability to form skeletal metastases. 相似文献
9.
Univ.Prof. Dr. Heinz Ludwig Dr. Rayko Evstatiev Univ.Prof. Dr. Gabriela Kornek Univ.Prof. Dr. Matti Aapro Univ.Prof. Dr. Thomas Bauernhofer Dr. Veronika Buxhofer-Ausch Univ.Prof. Dr. Michael Fridrik Univ.Prof. Dr. Dietmar Geissler Univ.Prof. Dr. Klaus Geissler Univ.Prof. Dr. Heinz Gisslinger Dr. Elisabeth Koller Dr. Gerhard Kopetzky Dr. Alois Lang Priv.Doz. Dr. Holger Rumpold Univ.Prof. Dr. Michael Steurer Dr. Houman Kamali Univ.Prof. Dr. Hartmut Link 《Wiener klinische Wochenschrift》2015,127(23-24):907-919
10.
Holger W. Unger Stephan Karl Regina A. Wangnapi Peter Siba Glen Mola Jane Walker Ivo Mueller Maria Ome Stephen J. Rogerson 《The American journal of tropical medicine and hygiene》2015,92(1):178-186
We conducted a prospective longitudinal study of fetal size in rural Papua New Guinea (PNG) involving 439 ultrasound-dated singleton pregnancies with no obvious risk factors for growth restriction. Sonographically estimated fetal weights (EFWs; N = 788) and birth weights (N = 376) were included in a second-order polynomial regression model (optimal fit) to generate fetal weight centiles. Means for specific fetal biometric measurements were also estimated. Fetal weight centiles from a healthy PNG cohort were consistently lower than those derived from Caucasian and Congolese populations, which overestimated the proportion of fetuses measuring small for gestational age (SGA; < 10th centile). Tanzanian and global reference centiles (Caucasian weight reference adapted to our PNG cohort) were more similar to those observed in our cohort, but the global reference underestimated SGA. Individual biometric measurements did not differ significantly from other cohorts. In rural PNG, a locally derived nomogram may be most appropriate for detection of SGA fetuses. 相似文献