全文获取类型
收费全文 | 1217篇 |
免费 | 107篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 68篇 |
妇产科学 | 12篇 |
基础医学 | 225篇 |
口腔科学 | 17篇 |
临床医学 | 132篇 |
内科学 | 218篇 |
皮肤病学 | 71篇 |
神经病学 | 67篇 |
特种医学 | 130篇 |
外科学 | 104篇 |
综合类 | 22篇 |
预防医学 | 166篇 |
眼科学 | 12篇 |
药学 | 63篇 |
中国医学 | 2篇 |
肿瘤学 | 74篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 22篇 |
2020年 | 12篇 |
2019年 | 24篇 |
2018年 | 30篇 |
2017年 | 15篇 |
2016年 | 28篇 |
2015年 | 29篇 |
2014年 | 44篇 |
2013年 | 59篇 |
2012年 | 64篇 |
2011年 | 69篇 |
2010年 | 64篇 |
2009年 | 61篇 |
2008年 | 67篇 |
2007年 | 105篇 |
2006年 | 58篇 |
2005年 | 54篇 |
2004年 | 35篇 |
2003年 | 21篇 |
2002年 | 18篇 |
2001年 | 25篇 |
2000年 | 16篇 |
1999年 | 21篇 |
1998年 | 36篇 |
1997年 | 42篇 |
1996年 | 28篇 |
1995年 | 25篇 |
1994年 | 31篇 |
1993年 | 20篇 |
1992年 | 11篇 |
1991年 | 19篇 |
1990年 | 14篇 |
1989年 | 38篇 |
1988年 | 29篇 |
1987年 | 19篇 |
1986年 | 11篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 10篇 |
1975年 | 4篇 |
1966年 | 2篇 |
排序方式: 共有1385条查询结果,搜索用时 15 毫秒
991.
Angèle PM Kerckhoffs 《World journal of gastroenterology : WJG》2009,15(23):2887-2892
AIM: To determine the composition of both fecal and duodenal mucosa-associated microbiota in irritable bowel syndrome (IBS) patients and healthy subjects using molecular-based techniques.
METHODS: Fecal and duodenal mucosa brush samples were obtained from 41 IBS patients and 26 healthy subjects. Fecal samples were analyzed for the composition of the total microbiota using fluorescent in situ hybridization (FISH) and both fecal and duodenal brush samples were analyzed for the composition of bifidobacteria using real-time polymerase chain reaction.
RESULTS: The FISH analysis of fecal samples revealed a 2-fold decrease in the level of bifidobacteria (4.2 ± 1.3 vs 8.3 ± 1.9, P 〈 0.01) in IBS patients compared to healthy subjects, whereas no major differences in other bacterial groups were observed. At the species level, Bifidobacterium catenulatum levels were significantly lower (6 ± 0.6 vs 19 ± 2.5, P 〈 0.001) in the IBS patients in both fecal and duodenal brush samples than in healthy subjects.
CONCLUSION: Decreased bifidobacteria levels in both fecal and duodenal brush samples of IBS patients compared to healthy subjects indicate a role for microbiotic composition in IBS pathophysiology. 相似文献
METHODS: Fecal and duodenal mucosa brush samples were obtained from 41 IBS patients and 26 healthy subjects. Fecal samples were analyzed for the composition of the total microbiota using fluorescent in situ hybridization (FISH) and both fecal and duodenal brush samples were analyzed for the composition of bifidobacteria using real-time polymerase chain reaction.
RESULTS: The FISH analysis of fecal samples revealed a 2-fold decrease in the level of bifidobacteria (4.2 ± 1.3 vs 8.3 ± 1.9, P 〈 0.01) in IBS patients compared to healthy subjects, whereas no major differences in other bacterial groups were observed. At the species level, Bifidobacterium catenulatum levels were significantly lower (6 ± 0.6 vs 19 ± 2.5, P 〈 0.001) in the IBS patients in both fecal and duodenal brush samples than in healthy subjects.
CONCLUSION: Decreased bifidobacteria levels in both fecal and duodenal brush samples of IBS patients compared to healthy subjects indicate a role for microbiotic composition in IBS pathophysiology. 相似文献
992.
J. Knol M. D’Hondt E. J. Dozois J. Vanden Boer P. Malisse 《Techniques in coloproctology》2009,13(1):65-68
The combination of standard laparoscopy and specimen extraction through a natural orifice has the potential to decrease wound
related complications. We describe the technical approach to laparoscopic sigmoidectomy in which the specimen is extracted
transanally through a proctoscope. Laparoscopic-assisted sigmoidectomy with transanal specimen removal avoids an abdominal
wall extraction incision and may be considered an alternative approach to conventional minimally invasive sigmoidectomy in
patients with disease of the sigmoid or left colon. 相似文献
993.
David Olmos Daniel Brewer Jeremy Clark Daniel C Danila Chris Parker Gerhardt Attard Martin Fleisher Alison HM Reid Elena Castro Shahneen K Sandhu Lorraine Barwell Nikhil Babu Oommen Suzanne Carreira Charles G Drake Robert Jones Prof Colin S Cooper Prof Howard I Scher Prof Johann S de Bono 《The lancet oncology》2012,13(11):1114-1124
994.
Knol A 《Nederlands tijdschrift voor geneeskunde》2001,145(30):1476-7; author reply 1477-8
995.
Recent changes in breast cancer incidence and risk factor prevalence in San Francisco Bay area and California women: 1988 to 2004
下载免费PDF全文
![点击此处可从《Breast cancer research : BCR》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Theresa HM Keegan Ellen T Chang Esther M John Pamela L Horn-Ross Margaret R Wrensch Sally L Glaser Christina A Clarke 《Breast cancer research : BCR》2007,9(5):R62
Introduction
Historically, the incidence rate of breast cancer among non-Hispanic white women living in the San Francisco Bay area (SFBA) of California has been among the highest in the world. Substantial declines in breast cancer incidence rates have been documented in the United States and elsewhere during recent years. In light of these reports, we examined recent changes in breast cancer incidence and risk factor prevalence among non-Hispanic white women in the SFBA and other regions of California. 相似文献996.
997.
Low basal salivary cortisol is associated with teacher-reported symptoms of conduct disorder 总被引:7,自引:0,他引:7
Cortisol has been implicated in psychobiological explanations of antisocial behavior. This study measured basal salivary cortisol in a sample of 25 children (age range 6 to 12 years) selected to vary in levels of antisocial behavior. Regression analyses were used to predict cortisol concentrations from parent- and teacher-reported symptoms. Parent-reported symptoms did not predict basal cortisol. Teacher-reported conduct disorder (CD) symptoms explained 38% of the variance in the cortisol concentrations, with high symptom severity associated with low cortisol. When a distinction was made between aggressive and non-aggressive CD symptoms, aggressive CD symptoms were more clearly related to low cortisol than non-aggressive CD symptoms. In contrast to previous research, no evidence was found for a mediating role of anxiety symptoms in the relationship between CD and cortisol. The results support biologically based models of antisocial behavior in children that involve reduced autonomic activity. 相似文献
998.
Bakker-Zierikzee AM Alles MS Knol J Kok FJ Tolboom JJ Bindels JG 《The British journal of nutrition》2005,94(5):783-790
Adding prebiotics or probiotics to infant formula to improve the intestinal flora of formula-fed infants is considered to be a major innovation. Several companies have brought relevant formulations onto the market. However, comparative data on the effects of pre- and probiotics on the intestinal microflora of infants are not available. The present study aimed to compare the effects of infant formula containing a mixture of galacto- and fructo-oligosaccharides or viable Bifidobacterium animalis on the composition and metabolic activity of the intestinal microflora. Before birth, infants were randomised and double blindly allocated to one of three formulas. The prebiotic (GOS/FOS) group (n 19) received regular infant formula supplemented with a mixture of galacto-oligosaccharides and fructo-oligosaccharides (6 g/l). The probiotic (Bb-12) group (n 19) received the same formula supplemented with 6.0x10(10) viable cells of B. animalis per litre. The standard group (n 19) received non-supplemented regular formula. A group of sixty-three breast-fed infants was included as a reference group. Faecal samples were taken at postnatal day 5 and 10, and week 4, 8, 12 and 16. Compared with the groups fed Bb-12 and standard formula, the GOS/FOS formula group showed higher faecal acetate ratio (69.7 % (sem 2.7), 69.9 % (sem 3.9) and 82.2 % (sem 5.3); P<0.05) and lactate concentration (11.3 (sem 7.9), 3.1 (sem 2.3) and 34.7 (sem 10.7) mmol/kg faeces) and lower pH (6.6 (sem 0.2), 7.1 (sem 0.2) and 5.6 (sem 0.2); P<0.05) at 16 weeks. Differences in percentage of bifidobacteria between the GOS/FOS (59.2 % (sem 7.7)), Bb-12 (52.7 % (sem 8.0)) and the standard (51.8 % (sem 6.4)) groups were not statistically significant at 16 weeks. Feeding infants GOS/FOS formula resulted in a similar effect on metabolic activity of the flora as in breast-fed infants. In the Bb-12 group, composition and metabolic activity of the flora were more similar to those of the standard group. 相似文献
999.
1000.