全文获取类型
收费全文 | 4210篇 |
免费 | 467篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 91篇 |
妇产科学 | 43篇 |
基础医学 | 515篇 |
口腔科学 | 68篇 |
临床医学 | 560篇 |
内科学 | 1064篇 |
皮肤病学 | 68篇 |
神经病学 | 453篇 |
特种医学 | 104篇 |
外科学 | 787篇 |
综合类 | 25篇 |
一般理论 | 2篇 |
预防医学 | 300篇 |
眼科学 | 60篇 |
药学 | 204篇 |
中国医学 | 2篇 |
肿瘤学 | 274篇 |
出版年
2024年 | 8篇 |
2023年 | 91篇 |
2022年 | 129篇 |
2021年 | 334篇 |
2020年 | 156篇 |
2019年 | 242篇 |
2018年 | 267篇 |
2017年 | 183篇 |
2016年 | 159篇 |
2015年 | 212篇 |
2014年 | 242篇 |
2013年 | 209篇 |
2012年 | 345篇 |
2011年 | 331篇 |
2010年 | 175篇 |
2009年 | 132篇 |
2008年 | 229篇 |
2007年 | 202篇 |
2006年 | 163篇 |
2005年 | 164篇 |
2004年 | 128篇 |
2003年 | 97篇 |
2002年 | 101篇 |
2001年 | 34篇 |
2000年 | 17篇 |
1999年 | 27篇 |
1998年 | 17篇 |
1997年 | 11篇 |
1996年 | 7篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1988年 | 9篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1981年 | 7篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1973年 | 9篇 |
1970年 | 6篇 |
1969年 | 9篇 |
1968年 | 9篇 |
1965年 | 8篇 |
1963年 | 10篇 |
排序方式: 共有4686条查询结果,搜索用时 15 毫秒
61.
62.
Saumya Jayakumar Michael S. Middleton Eric J. Lawitz Parvez S. Mantry Stephen H. Caldwell Hays Arnold Anna Mae Diehl Reem Ghalib Magdy Elkhashab Manal F. Abdelmalek Kris V. Kowdley C. Stephen Djedjos Ren Xu Ling Han G. Mani Subramanian Robert P. Myers Zachary D. Goodman Nezam H. Afdhal Rohit Loomba 《Journal of hepatology》2019,70(1):133-141
63.
Zachary Bauman Victor Coba Marika Gassner David Amponsah John Gallien Dionne Blyden Keith Killu 《Journal of Ultrasound》2015,18(4):343-348
Purpose
Point-of-care ultrasound evaluates inferior vena cava (IVC) and internal jugular vein (IJV) measurements to estimate intravascular volume status. The reliability of the IVC and IJV collapsibility index during increased thoracic or intra-abdominal pressure remains unclear.Methods
Three phases of sonographic scanning were performed: spontaneous breathing phase, increased thoracic pressure phase via positive pressure ventilation (PPV) phase, and increased intra-abdominal pressure (IAP) phase via laparoscopic insufflation to 15 mmHg. IVC measurements were done at 1–2 cm below the diaphragm and IJV measurements were done at the level of the cricoid cartilage during a complete respiratory cycle. Collapsibility index was calculated by (max diameter − min diameter)/max diameter × 100 %. Chi square, t test, correlation procedure (CORR) and Fisher’s exact analyses were completed.Results
A total of 144 scans of the IVC and IJV were completed in 16 patients who underwent laparoscopic surgery. Mean age was 46 ± 15 years, with 75 % female and 69 % African-American. IVC and IJV collapsibility correlated in the setting of spontaneous breathing (r2 = 0.86, p < 0.01). IVC collapsibility had no correlation with the IJV in the setting of PPV (r2 = 0.21, p = 0.52) or IAP (r2 = 0.26, p = 0.42). Maximal IVC diameter was significantly smaller during increased IAP (16.5 mm ± 4.9) compared to spontaneous breathing (20.6 mm ± 4.8, p = 0.04) and PPV (21.8 mm ± 5.6, p = 0.01).Conclusion
IJV and IVC collapsibility correlated during spontaneous breathing but there was no statistically significant correlation during increased thoracic or intra-abdominal pressure. Increased intra-abdominal pressure was associated with a significant smaller maximal IVC diameter and cautions the reliability of IVC diameter in clinical settings that are associated with intra-abdominal hypertension or abdominal compartment syndrome. 相似文献64.
Zobair Younossi Maria Stepanova Arun J. Sanyal Stephen A. Harrison Vlad Ratziu Manal F. Abdelmalek Anna Mae Diehl Stephen Caldwell Mitchell L. Shiffman Raul Aguilar Schall Bryan McColgan G. Mani Subramanian Robert P. Myers Andrew Muir Nezam H. Afdhal Jaime Bosch Zachary Goodman 《Journal of hepatology》2018,68(6):1365-1370
65.
66.
67.
Zachary Austin Crannell Miguel Mauricio Cabada Alejandro Castellanos-Gonzalez Ayesha Irani Arthur Clinton White Rebecca Richards-Kortum 《The American journal of tropical medicine and hygiene》2015,92(3):583-587
Giardia duodenalis is one of the most commonly identified parasites in stool samples. Although relatively easy to treat, giardiasis can be difficult to detect as it presents similar to other diarrheal diseases. Here, we present a recombinase polymerase amplification-based Giardia (RPAG) assay to detect the presence of Giardia in stool samples. The RPAG assay was characterized on the bench top using stool samples spiked with Giardia cysts where it showed a limit-of-detection nearly as low as the gold standard polymerase chain reaction assay. The RPAG assay was then tested in the highlands of Peru on 104 stool samples collected from the surrounding communities where it showed 73% sensitivity and 95% specificity against a polymerase chain reaction and microscopy composite gold standard. Further improvements in clinical sensitivity will be needed for the RPAG assay to have clinical relevance. 相似文献
68.
RAP74 induces promoter contacts by RNA polymerase II upstream and downstream of a DNA bend centered on the TATA box 下载免费PDF全文
69.