全文获取类型
收费全文 | 201907篇 |
免费 | 34222篇 |
国内免费 | 3132篇 |
专业分类
耳鼻咽喉 | 5689篇 |
儿科学 | 6314篇 |
妇产科学 | 3359篇 |
基础医学 | 9713篇 |
口腔科学 | 2424篇 |
临床医学 | 32454篇 |
内科学 | 57183篇 |
皮肤病学 | 8076篇 |
神经病学 | 18351篇 |
特种医学 | 8098篇 |
外国民族医学 | 3篇 |
外科学 | 49481篇 |
综合类 | 2016篇 |
现状与发展 | 75篇 |
一般理论 | 43篇 |
预防医学 | 10437篇 |
眼科学 | 4930篇 |
药学 | 4698篇 |
6篇 | |
中国医学 | 601篇 |
肿瘤学 | 15310篇 |
出版年
2024年 | 747篇 |
2023年 | 5160篇 |
2022年 | 1955篇 |
2021年 | 4541篇 |
2020年 | 6878篇 |
2019年 | 3338篇 |
2018年 | 8731篇 |
2017年 | 8405篇 |
2016年 | 9510篇 |
2015年 | 9763篇 |
2014年 | 17421篇 |
2013年 | 17913篇 |
2012年 | 9342篇 |
2011年 | 9451篇 |
2010年 | 12566篇 |
2009年 | 16052篇 |
2008年 | 8953篇 |
2007年 | 7386篇 |
2006年 | 9794篇 |
2005年 | 7086篇 |
2004年 | 5920篇 |
2003年 | 4647篇 |
2002年 | 4643篇 |
2001年 | 4573篇 |
2000年 | 3664篇 |
1999年 | 3907篇 |
1998年 | 4207篇 |
1997年 | 3975篇 |
1996年 | 3766篇 |
1995年 | 3624篇 |
1994年 | 2261篇 |
1993年 | 1829篇 |
1992年 | 1735篇 |
1991年 | 1723篇 |
1990年 | 1318篇 |
1989年 | 1419篇 |
1988年 | 1237篇 |
1987年 | 1033篇 |
1986年 | 1071篇 |
1985年 | 847篇 |
1984年 | 690篇 |
1983年 | 638篇 |
1982年 | 665篇 |
1981年 | 531篇 |
1980年 | 480篇 |
1979年 | 387篇 |
1978年 | 401篇 |
1977年 | 458篇 |
1975年 | 324篇 |
1972年 | 321篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
113.
Timothy Threlfall Neil Kent Peter Garcia-Webb Elizabeth Byrnes Paul Psaila-Savona 《Australian and New Zealand journal of public health》1993,17(4):379-381
Abstract: This study reports on an analysis of the lead concentrations in 123 venous blood samples collected from Perth children aged between two months and 17 years attending Princess Margaret Hospital. The overall geometric mean was 6.9 μg lead per 100 ml whole blood, with 95 per cent of results lying between 3.2 and 14.8 μg/100 ml. Among children under five years of age, those aged between 18 months and two years had the highest geometric mean blood lead (11.1 μg/100 ml). There were no consistent associations between geometric mean blood lead and area of residence, age group or sex. In this sample of Perth children, the mean blood lead concentration was lower than those reported in other studies. Less than 0.1 per cent of children of the age range studied would have been expected to have lead levels exceeding the NHMRC ‘level of concern’ (25 μg/100 ml) current at the time of the study. However, the recent adoption of goal of less than 10 μg/100 ml could mean that lead levels in up to 21 per cent of Perth children would now be regarded as excessive. 相似文献
114.
Tiziano Curti MD Gianandrea Pasquinelli MD Paola Preda BS Antonio Freyrie MD Renzo Laschi MD Massimo D’Addato MD 《Annals of vascular surgery》1989,3(4):351-363
Human adult endothelial cells were enzymatically harvested from adipose tissue. Cell viability was established by Trypan blue exclusion and transmission and scanning electron microscopy. Endothelial cells were identified by immunocytochemical investigation at light microscopy, transmission electron microscopy, and scanning electron microscopy. Isolated cells were positive for actin and vimentin, negative for desmin. Factor VIII RA was mainly expressed at cell surface and occasionally disclosed in the cytoplasm. Reactivity for UEA I and J15 was weak or undetectable. Human endothelial cells were seeded and left to adhere for one hour onto different nonvascular substrates (glass, poly-l-lysine, formvar-carbon, fibronectin, Teflon). Scanning electron microscopy defined surface features, suggesting tenacious cell adhesion on the substrate. Different vascular substrates were tested (preclotted Dacron, albumin Dacron, Hemashield Dacron, Gelseal Dacron, ePTFE, fibronectin-ePTFE). Commercially available coated grafts showed qualitative and quantitative differences in cell adhesion. In particular, Gelseal Dacron provided the best quantitative results, even though a wide variability was observed. In contrast, fibronectin-coated ePTFE gave more reliable results and high spreading efficiency. In the short term, coated grafts do not seem to offer greater advantages than fibronectin-coated ePTFE. However, specific incubation times for each coated graft should be selected and the long-term approach (graft culture) should also be attempted. 相似文献
115.
116.
117.
Paul Wexberg MD BM Richard Pacher MD Suzanne Rdler MD Katharina Kiss MD Gilbert Beran MD Michael Grimm MD Gerald Maurer MD Dietmar Glogar MD FESC 《The Journal of heart and lung transplantation》2002,21(12):583-1263
BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation. 相似文献
118.
119.
Because of its neurocognitive enhancing effects, Gingko biloba has emerged as amongst the most commonly used herbal products. We report a liver transplant recipient with potentially life-threatening toxicity resulting from Gingko biloba use. Seven days after a second liver transplantation for recurrent hepatitisB virus infection, subphrenic hematoma was documented in a 59-year-old Korean patient. Failure to control bleeding with CT-guided drainage necessitated exploratory laparotomy for the evacuation of a large subphrenic hematoma. Three weeks later, an episode of vitreous hemorrhage was documented. Unbeknownst to his care providers, the patient had been consuming Gingko biloba throughout the postoperative period. No further bleeding episodes occurred after the cessation of Gingko biloba use. Unrecognized use of herbal products may be associated with serious side effects and adverse clinical sequelae in transplant recipients. Given their increasing popularity, the use of herbal products should be routinely sought as part of the history in transplant recipients. 相似文献
120.