全文获取类型
收费全文 | 786篇 |
免费 | 32篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 48篇 |
妇产科学 | 4篇 |
基础医学 | 65篇 |
口腔科学 | 19篇 |
临床医学 | 37篇 |
内科学 | 100篇 |
皮肤病学 | 36篇 |
神经病学 | 8篇 |
特种医学 | 49篇 |
外科学 | 93篇 |
综合类 | 279篇 |
预防医学 | 24篇 |
眼科学 | 2篇 |
药学 | 24篇 |
1篇 | |
中国医学 | 3篇 |
肿瘤学 | 26篇 |
出版年
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 25篇 |
2014年 | 24篇 |
2013年 | 24篇 |
2012年 | 27篇 |
2011年 | 23篇 |
2010年 | 65篇 |
2009年 | 47篇 |
2008年 | 44篇 |
2007年 | 47篇 |
2006年 | 49篇 |
2005年 | 33篇 |
2004年 | 48篇 |
2003年 | 19篇 |
2002年 | 25篇 |
2001年 | 29篇 |
2000年 | 20篇 |
1999年 | 20篇 |
1998年 | 27篇 |
1997年 | 30篇 |
1996年 | 30篇 |
1995年 | 17篇 |
1994年 | 22篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1955年 | 1篇 |
1953年 | 1篇 |
排序方式: 共有821条查询结果,搜索用时 15 毫秒
91.
Aneurysm of sinus of Valsalva dissecting into interventricular septum is a rare entity. We report one such case who was incidentally diagnosed by echocardiography to have this abnormality during evaluation of a clinically suspected isolated aortic regurgitation.KEY WORDS: Aneurysm – dissecting – sinus of Valsalva, Echocardiography 相似文献
92.
Nina Holzer Karl F. Braun Sabrina Ehnert José T. Ega?a Thilo L. Schenck Arne Buchholz Lilianna Schyschka Markus Neumaier Steffen Benzing Ulrich St?ckle Thomas Freude Andreas K. Nussler 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2012,397(3):467-474
Purpose
Recent reports discuss the altered bone homeostasis in cigarette smokers, being a risk factor for osteoporosis and negatively influencing fracture healing. Cigarette smoke is known to induce oxidative stress in the body via an increased production of reactive oxygen species (ROS). These increases in ROS are thought to damage the bone-forming osteoblasts. Naturally occurring polyphenols contained in green tea extract (GTE), e.g., catechins, are known to have anti-oxidative properties. Therefore, the aim of this study was to investigate whether GTE and especially catechins protect primary human osteoblasts from cigarette smoke-induced damage and to identify the underlying mechanisms.Methods
Primary human osteoblasts were isolated from patients?? femur heads. Cigarette smoke medium (CSM) was obtained using a gas-washing bottle and standardized by its optical density (OD320) at ???=?320?nm. ROS formation was measured using 2??7??dichlorofluorescein diacetate, and osteoblasts?? viability was detected by resazurin conversion.Results
Co-, pre-, and post-incubation with GTE and catechins significantly reduced ROS formation and thus improved the viability of CSM-treated osteoblasts. Besides GTE??s direct radical scavenging properties, pre-incubation with both GTE and catechins protected osteoblasts from CSM-induced damage. Inhibition of the anti-oxidative enzyme HO-1 significantly reduced the protective effect of GTE and catechins emphasizing the key role of this enzyme in GTE anti-oxidative effect.Conclusions
Our data suggest possible beneficial effects on bone homeostasis, fracture healing, and bone mineral density following a GTE-rich diet or supplementation. 相似文献93.
94.
95.
96.
The purpose of this study was to describe the normal variation in perianal anatomy in preschool children, selected for non-abuse, and to compare the findings in two examination positions. A letter of invitation was sent to 3773 children, after which 305 children (103 boys and 202 girls) were recruited. Inclusion in the study was based on self-selection, whereby parents who did not suspect any occurrence of sexual abuse of their child gave informed consent to participate. The mean age of the children was 5.63 y (range: 5.13-6.75). An anal examination was performed in the left lateral position (LLP) and the prone knee-chest position (KCP), for approximately 30 s each. A colposcope and a camera were used. All data were systematically analysed for gender differences, and a paired sample test was used to compare findings in LLP and KCP. Venous congestion in LLP and external anal dilatation in both positions were significantly more common in girls, while midline depressions and smooth areas (both positions) were significantly more common in boys. External and total anal dilatation, midline smooth areas and depressions and the occurrence of a prominent anal verge were significantly more common in the KCP. The finding of total anal dilatation was rare. CONCLUSION: We observed several gender and position differences in perianal anatomy, and most of these findings seem to be related to structure and tone in the anal muscles. 相似文献
97.
98.
Hepatic endometriosis is extremely rare. The diagnosis is often missed and treatment is delayed. A 37-year-old woman was referred to the gynaecology department with vague abdominal pains. She had a past history of pelvic endometriosis and hysterectomy with bilateral salpingo-oophorectomy. Further investigations in due course confirmed it to be endometriosis of the liver. She was eventually referred to the hepatobiliary unit, almost three years after her first presentation, where she was operated on with good results. 相似文献
99.
SH Opdal TO Rognum Å Vege AK Stave BM Dupuy T Egeland 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(10):1039-1044
The purpose of the present study was to investigate substitutions in the D-loop of mitochondrial DNA (mtDNA) in sudden infant death syndrome (SIDS) and controls, since several observations indicate the involvement of mtDNA mutations in SIDS. These include elevated levels of vitreous humour hypoxanthine in SIDS victims, familial clustering without mendelian traits, and observations of increased sleepiness and a lower activity score in infants who later succumbed to SIDS. Eighty-two cases of SIDS and 133 controls were investigated and the D-loop sequences were recorded in the base-pair range 16 055-16 500 in the mtDNA sequence. The sequencing was carried out using the Applied Biosystems Sequenase dye terminator method and a ABD373A sequencer. The recorded D-loop sequences were compared with the Cambridge sequence and differences were recorded as substitutions. The SIDS cases had a tendency towards a higher substitution rate in the D-loop than the controls ( p = 0.088). This observation makes it interesting to search for deleterious mutations in other locations in the mtDNA. 相似文献
100.
Saussele T Burk O Blievernicht JK Klein K Nussler A Nussler N Hengstler JG Eichelbaum M Schwab M Zanger UM 《Clinical pharmacology and therapeutics》2007,82(3):265-274
The pyrazolone drug metamizole is a widely used analgesic. Analysis of liver microsomes from patients treated with metamizole revealed selectively higher expression of cytochromes P450, CYP2B6 and CYP3A4 (3.8- and 2.8-fold, respectively), and 2.9-fold higher bupropion hydroxylase activity compared with untreated subjects. Further investigation of metamizole and various derivatives on different potential target genes in human primary hepatocytes demonstrated time- and concentration-dependent induction by metamizole of CYP2B6 (7.8- and 3.1-fold for mRNA and protein, respectively, at 100 muM) and CYP3A4 (2.4- and 2.9-fold, respectively), whereas other genes (CYP2C9, CYP2C19, CYP2D6, NADPH:cytochrome P450 reductase, ABCB1, constitutive androstane receptor (CAR), pregnane X receptor (PXR)) were not substantially altered. Using reporter gene assays, we show that metamizole is not acting as a direct ligand to either PXR or CAR, suggesting a phenobarbital-like mechanism of induction. These data warrant further studies to elucidate the drug-interaction potential of metamizole, especially in patients with long-term treatment. 相似文献