全文获取类型
收费全文 | 827篇 |
免费 | 62篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 51篇 |
妇产科学 | 6篇 |
基础医学 | 80篇 |
口腔科学 | 70篇 |
临床医学 | 76篇 |
内科学 | 126篇 |
皮肤病学 | 27篇 |
神经病学 | 38篇 |
特种医学 | 218篇 |
外科学 | 44篇 |
综合类 | 34篇 |
预防医学 | 47篇 |
眼科学 | 5篇 |
药学 | 32篇 |
肿瘤学 | 56篇 |
出版年
2021年 | 4篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 8篇 |
2014年 | 16篇 |
2013年 | 10篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 20篇 |
2009年 | 22篇 |
2008年 | 20篇 |
2007年 | 17篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 14篇 |
2000年 | 9篇 |
1999年 | 16篇 |
1998年 | 40篇 |
1997年 | 45篇 |
1996年 | 41篇 |
1995年 | 37篇 |
1994年 | 23篇 |
1993年 | 31篇 |
1992年 | 21篇 |
1991年 | 24篇 |
1990年 | 16篇 |
1989年 | 29篇 |
1988年 | 33篇 |
1987年 | 52篇 |
1986年 | 31篇 |
1985年 | 26篇 |
1984年 | 15篇 |
1983年 | 18篇 |
1982年 | 15篇 |
1981年 | 20篇 |
1980年 | 17篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 11篇 |
1976年 | 23篇 |
1975年 | 11篇 |
1972年 | 4篇 |
1934年 | 4篇 |
1927年 | 4篇 |
1926年 | 4篇 |
排序方式: 共有911条查询结果,搜索用时 156 毫秒
21.
22.
23.
24.
DR Brewster MJ Manary IS Menzies EV O'Loughlin RL Henry 《Archives of disease in childhood》1997,76(3):236-241
Intestinal permeability can be assessed non-invasively using the lactulose-rhamnose (L-R) test, which is a reliable measure of small intestinal integrity. AIMS: To determine risk factors for abnormal intestinal permeability in kwashiorkor, and to measure changes in L-R ratios with inpatient rehabilitation. DESIGN: A case-control study of 149 kwashiorkor cases and 45 hospital controls. The L-R test was adapted to study kwashiorkor in Malawi, with testing at weekly intervals during nutritional rehabilitation. Urine sugars were measured by thin layer chromatography in London. RESULTS: The initial geometric mean L-R ratios (x100) (with 95% confidence interval) in kwashiorkor were 17.3 (15.0 to 19.8) compared with 7.0 (5.6 to 8.7) for controls. Normal ratios are < 5, so the high ratios in controls indicate tropical enteropathy syndrome. Abnormal permeability in kwashiorkor was associated with death, oliguria, sepsis, diarrhoea, wasting and young age. Diarrhoea and death were associated with both decreased L-rhamnose absorption (diminished absorptive surface area) and increased lactulose permeation (impaired barrier function) whereas nutritional wasting affected only L-rhamnose absorption. Despite, clinical recovery, mean L-R ratios improved little on treatment, with mean weekly ratios of 16.3 (14.0 to 19.0), 13.3 (11.1 to 15.9) and 14.4 (11.0 to 18.8). CONCLUSION: Abnormal intestinal permeability in kwashiorkor correlates with disease severity, and improves only slowly with nutritional rehabilitation. 相似文献
25.
Interactive suppression of aberrant crypt foci induced by azoxymethane in rat colon by phytic acid and green tea 总被引:1,自引:2,他引:1
Several epidemiological studies point to a strong correlation between
nutrient composition of the diet and cancer of the colon. Phytic acid,
present in grains, has been credited with reducing the risk of cancer of
the colon. A number of reports are available indicating the benefits of
green tea consumption in reducing the risk of stomach, lung and skin
cancer, but little data are available on the effect of green tea in
reducing the risk of colon cancer. Also, there are no studies on the
combined effect of these compounds on colon tumorigenesis. Thus the primary
objective of this investigation was to elucidate the combined effects of
green tea and phytic acid on colonic preneoplastic lesions and the Phase II
enzyme glutathione S-transferase. Fisher 344 male weanling rats were
divided into nine groups of 15 rats each and fed the experimental diet for
13 weeks. Rats received two s.c. injections of azoxymethane in saline at 16
mg/kg body wt at 7 and 8 weeks of age. Rats received three levels (0, 1 and
2%) of phytic acid with three levels (0, 1 and 2%) of green tea within each
phytic acid level in a 3 x 3 factorial experiment. Results indicate that
while green tea had a marginal effect (P < 0.14), phytic acid
significantly reduced the incidence of aberrant crypt foci (P < 0.008).
The interaction between green tea and phytic acid was significant (P <
0.029 for distal and < 0.0168 for entire colon) and positive, pointing
to a synergistic effect of green tea and phytic acid.
相似文献
26.
T. Stober J. L. Bermejo F. S. Schwindling M. Schmitter 《Journal of oral rehabilitation》2016,43(8):621-629
The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6‐, 12‐, and 24‐month follow‐up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser‐scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two‐sided paired Student's t‐tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19–26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75–115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia‐opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified. 相似文献
27.
28.
29.
Reza Saeidi Pour DR MED DENT Otto Zuhr DR MED DENT Markus Hürzeler PROF DR MED DENT Otto Prandtner MDT Caroline Freitas Rafael Daniel Edelhoff PROF DR MED DENT Anja Liebermann DR MED DENT 《Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.]》2017,29(2):93-101
30.
BACKGROUND & AIMS: Shwachman syndrome is an inherited condition with multisystemic abnormalities, including exocrine pancreatic dysfunction. The aim of this study was to evaluate the occurrence and progression of features in a large cohort of patients. METHODS: Clinical records of 25 patients with Shwachman syndrome were reviewed. RESULTS: Mean birth weight (2.92 +/- 0.51 kg) was at the 25th percentile. However, by 6 months of age, mean heights and weights were less than the 5th percentile. After 6 months of age, growth velocity was normal. Severe fat maldigestion due to pancreatic insufficiency was present in early life (fecal fat, 26% +/- 17% of fat intake; age, < 2 years). Serial assessment of exocrine pancreatic function showed persistent deficits of enzyme secretion, but 45% of patients showed moderate age-related improvements leading to pancreatic sufficiency. Neutropenia was the most common hematologic abnormality (88%), but leukopenia, thrombocytopenia, and anemia were also frequently encountered. Patients with hypoplasia of all three bone marrow cellular lines (n = 11) had the worst prognosis; 5 patients died, 2 of sepsis and 3 of acute myelogenous leukemia. Other findings included hepatomegaly and/or abnormal liver function test results and skeletal abnormalities. CONCLUSIONS: A wide and varied spectrum of phenotypic abnormalities among patients with Shwachman syndrome is described. Pancreatic acinar dysfunction is an invariable abnormality. Patients with severe bone marrow involvement may have a guarded prognosis. (Gastroenterology 1996 Dec;111(6):1593-602) 相似文献