全文获取类型
收费全文 | 18849篇 |
免费 | 902篇 |
国内免费 | 106篇 |
学科分类
医药卫生 | 19857篇 |
出版年
2023年 | 144篇 |
2022年 | 305篇 |
2021年 | 646篇 |
2020年 | 368篇 |
2019年 | 569篇 |
2018年 | 681篇 |
2017年 | 434篇 |
2016年 | 452篇 |
2015年 | 569篇 |
2014年 | 778篇 |
2013年 | 962篇 |
2012年 | 1543篇 |
2011年 | 1682篇 |
2010年 | 957篇 |
2009年 | 768篇 |
2008年 | 1272篇 |
2007年 | 1433篇 |
2006年 | 1223篇 |
2005年 | 1083篇 |
2004年 | 946篇 |
2003年 | 786篇 |
2002年 | 804篇 |
2001年 | 106篇 |
2000年 | 89篇 |
1999年 | 101篇 |
1998年 | 124篇 |
1997年 | 105篇 |
1996年 | 87篇 |
1995年 | 58篇 |
1994年 | 60篇 |
1993年 | 44篇 |
1992年 | 40篇 |
1991年 | 40篇 |
1990年 | 41篇 |
1989年 | 32篇 |
1988年 | 34篇 |
1987年 | 30篇 |
1986年 | 24篇 |
1985年 | 24篇 |
1984年 | 31篇 |
1983年 | 31篇 |
1982年 | 18篇 |
1981年 | 31篇 |
1980年 | 23篇 |
1979年 | 23篇 |
1978年 | 29篇 |
1977年 | 28篇 |
1976年 | 22篇 |
1971年 | 23篇 |
1970年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Alejandra Gordillo Hernández Eduardo Dominguez-Adame Lanuza Auxiliadora Cano Matias Rosario Perez Huertas Katherine Maria Gallardo Rodriguez Purificacion Gallinato Perez Fernando Oliva Mompean 《World journal of gastrointestinal surgery》2015,7(8):170-173
Gangliocytic paragangliomas are rare tumors that almost exclusively occur within the second portion of the duodenum. Although these tumors generally have a benign clinical course, they have the potential to recur or metastasize to regional lymph nodes. The case report presented here describes a 57-year-old female patient with melena, progressive asthenia, anemia, and a mass in the second-third portion of the duodenum that was treated by local excision. The patient was diagnosed with a friable bleeding tumor. The histologic analysis showed that the tumor was a 4 cm gangliocytic paraganglioma without a malignant cell pattern. In the absence of local invasion or distant metastasis, endoscopic resection represents a feasible, curative therapy. Although endoscopic polypectomy is currently considered the treatment of choice, it is not recommended if the size of the tumor is > 3 cm and/or there is active or recent bleeding. Patients diagnosed with a gangliocytic paraganglioma should be closely followed-up for possible local recurrence. 相似文献
2.
3.
4.
5.
6.
Miguel A. Sanz Pau Montesinos Haesook T. Kim Guillermo J. Ruiz-Argüelles María S. Undurraga María R. Uriarte Lem Martínez Rafael H. Jacomo Homero Gutiérrez-Aguirre Raul A. M. Melo Rosane Bittencourt Ricardo Pasquini Katia Pagnano Evandro M. Fagundes Edo Vellenga Alexandra Holowiecka Ana J. González-Huerta Pascual Fernández Javier De la Serna Salut Brunet Elena De Lisa José González-Campos José M. Ribera Isabel Krsnik Arnold Ganser Nancy Berliner Raul C. Ribeiro Francesco Lo-Coco Bob L?wenberg Eduardo M. Rego 《Annals of hematology》2015,94(8):1347-1356
7.
8.
Eduardo Krajewski Ian S Soriano Jorge Ortiz 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2006,10(4):426-431
BACKGROUND: Solid-organ transplantation has become the treatment of choice for patients with end-stage renal disease, end-stage liver failure, and some patients with type 1 diabetes mellitus. Similarly, surgical expertise and mechanical improvements have led to significant advances in laparoscopic surgery. Laparoscopic interventions are sometimes not pursued in transplant recipients due to the lack of strong supporting evidence for the use of laparoscopic techniques in these patients. METHODS: Using an extensive literature search, we review herein the available data on the utility of laparoscopic interventions in transplant recipients, with particular attention to the risks and benefits, indications, and contraindications for this complex patient population. RESULTS: Although randomized trials are few, multiple case reports indicate that many transplant recipients have benefited from laparoscopic interventions. CONCLUSION: The well-known benefits of laparoscopy could be extended to transplant recipients. 相似文献
9.
William A. Kennedy II Ralph Buttyan Eduardo Garcia-Montes Carl A. Olsson Ihor S. Sawczuk 《Urology》1997,49(6):973-980
Objectives. Acute unilateral ureteral obstruction (UUO) results in ipsilateral hydronephrosis characterized by a decrease in epidermal growth factor (EGF) mRNA expression and EGF protein levels in the distal renal tubules. UUO results in programmed cell death with increases in the characteristic markers of apoptosis. To suppress the apoptotic response during UUO, recombinant EGF was administered during renal obstruction and the ensuing molecular and histologic changes were studied.Methods. Mature Sprague-Dawley rats underwent left ureteral obstruction and the kidneys were harvested at 24, 48, and 72 hours. Markers of apoptosis included DNA laddering pattern on agarose gel electrophoresis, in situ gap labeling of fragmented DNA for quantitative apoptotic body determination, polyadenylated mRNA expression of SGP-2, and in situ hybridization for sulfated glycoprotein-2 (SGP-2) mRNA. Studies were repeated in rats following administration of 10, 20, and 40 μg of subcutaneous recombinant EGF on a daily basis after UUO.Results. Subcutaneous injection of EGF into unilaterally obstructed rats promotes renal tubular epithelial cell regeneration, as demonstrated by increased cortical mitotic activity. Systemic EGF supplementation in these unilaterally obstructed rats also resulted in a decrease in the intensity of the DNA laddering pattern associated with renal tubular apoptosis. An in situ labeling procedure to identify apoptotic nuclei in the ureterally obstructed kidneys revealed a 50% reduction in apoptosis after EGF administration. Northern blot analysis and in situ hybridization for SGP-2 mRNA or clusterin gene product also revealed a decreased expression in the obstructed and EGF-treated renal parenchyma.Conclusions. These data suggest that EGF, apart from its known role as a mitogenic substance for renal tubular epithelial cells, is also a critical in vivo renal cell survival factor for the developmentally mature kidney. 相似文献
10.
Uptake of Adriamycin in tumour and surrounding brain tissue in patients with malignant gliomas 总被引:1,自引:0,他引:1
H. von Holst E. Knochenhauer H. Blomgren V. P. Collins L. Ehn M. Lindquist G. Norén C. Peterson 《Acta neurochirurgica》1990,104(1-2):13-16
Summary Eight patients with malignant gliomas verified on CT scan, received an intravenous injection of 50 mg of Adriamycin R, 24 hours prior to surgical removal of the tumour. Peroperatively, both tumour and surrounding tissue specimens were obtained for determination of the tissue concentrations of Adriamycin and its reduced metabolite Adriamycinol. It was found that Adriamycin could be detected in tumour tissue from all patients. The concentration varied between 0,9 and 4,6 nmol/g tissue. In contrast, Adriamycin could only be detected in surrounding brain tissue from one patient.In anin vitro study a human malignant glioma cell line (U-251 MG) was exposed to various concentrations of Adriamycin for 24 hours. It was found that an intracellular drug concentration above 30 nmol/g cells caused a concentration dependent inhibition of cell growth. Thus, it is likely that the poor effect of Adriamycin on patients with malignant gliomas is due to an ineffective drug accumulation in the tumour tissue. 相似文献