全文获取类型
收费全文 | 644篇 |
免费 | 38篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 47篇 |
妇产科学 | 20篇 |
基础医学 | 68篇 |
口腔科学 | 37篇 |
临床医学 | 91篇 |
内科学 | 163篇 |
皮肤病学 | 10篇 |
神经病学 | 32篇 |
特种医学 | 115篇 |
外科学 | 24篇 |
综合类 | 10篇 |
预防医学 | 19篇 |
眼科学 | 3篇 |
药学 | 57篇 |
1篇 | |
肿瘤学 | 29篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 16篇 |
2014年 | 19篇 |
2013年 | 25篇 |
2012年 | 9篇 |
2011年 | 14篇 |
2010年 | 19篇 |
2009年 | 20篇 |
2008年 | 7篇 |
2007年 | 40篇 |
2006年 | 17篇 |
2005年 | 10篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 45篇 |
1997年 | 52篇 |
1996年 | 55篇 |
1995年 | 44篇 |
1994年 | 31篇 |
1993年 | 30篇 |
1992年 | 2篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 16篇 |
1988年 | 27篇 |
1987年 | 19篇 |
1986年 | 14篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1973年 | 1篇 |
1967年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有728条查询结果,搜索用时 15 毫秒
101.
102.
Tumor oxygen levels were measured with an electrode in 13 patients with colon carcinoma metastases. These measurements were correlated with images obtained with radiolabeled monoclonal antibody 1083-17-1A. Only those tumors or tumor regions with a mean PO2 of 16 mm Hg or greater were successfully imaged. Tumors and tumor regions with a mean PO2 of less than 16 mm Hg were not imaged, even when the presence of antigen was confirmed with biopsy. These data suggest that physiologic factors other than antigen expression may affect antibody uptake. 相似文献
103.
104.
M Taglialatela L M Canzoniero S Amoroso A Fatatis G F Di Renzo L Annunziato 《Brain research》1989,488(1-2):114-120
Recently, it has been demonstrated that Ca2+ entrance into the neuronal cytoplasm can occur upon the activation of 3 different types of specific voltage-dependent channels which can be characterized according to the following criteria: (1) voltage threshold for activation; (2) tendency to inactivation; (3) bivalent cation permeability; and (4) drug sensitivity. In this study we investigated, in tuberoinfundibular dopaminergic (TIDA) hypothalamic neurons, the biochemical and pharmacological properties of Ca2+ channels, by comparing the effects of high extracellular concentrations of Ba2+ and Ca2+ ions on [3H]dopamine (DA) release from TIDA neurons. The results obtained show that extracellular Ba2+ ion concentrations dose-dependently (10-20 mM) stimulated [3H]DA release from superfused TIDA neurons and that this effect was prevented by Co2+ ions (2 mM). In addition, superfusion of TIDA neurons with a concentration of Ca2+ ions equimolar to that of Ba2+ ions (20 mM) failed to modify [3H]DA release. The fact that tetraethylammonium (10 mM), a blocker of K+ currents in excitable cells, did not mimick the stimulatory action of Ba2+ ions on [3H]DA release, seems to exclude that the effect of Ba2+ ions was dependent on the inhibition of K+ channels in TIDA neurons. The omission of Ca2+ ions from the extracellular medium did not prevent the stimulatory effect on [3H]DA release elicited by elevated concentrations of Ba2+ ions, but rather reinforced this effect. Finally, nitrendipine (50 microM) did not modify the stimulatory effect of high extracellular Ba2+ ions on [3H]DA release from TIDA neurons. 相似文献
105.
106.
107.
108.
109.
Suspected leaking abdominal aortic aneurysm: use of sonography in the emergency room 总被引:5,自引:0,他引:5
Shuman WP; Hastrup W JR; Kohler TR; Nyberg DA; Wang KY; Vincent LM; Mack LA 《Radiology》1988,168(1):117-119
To determine the value of sonography in the emergent evaluation of suspected leaking abdominal aortic aneurysms, the authors examined 60 patients in the emergency department using sonography and a protocol involving advance radio notification from the ambulance; arrival of sonographic personnel and equipment in the triage room before patient arrival; and, during other triage activities, rapid sonographic evaluation of the aorta for aneurysm and of the paraaortic region for extraluminal blood. Sonographic findings were correlated with surgical results and clinical outcome. When performed under these circumstances, sonography was accurate in demonstrating presence or absence of aneurysm (98%), but its sensitivity for extraluminal blood was poor (4%). A combination of sonographic confirmation of aneurysm, abdominal pain, and unstable hemodynamic condition resulted in the correct decision to perform emergent surgery in 21 of 22 patients (95%). An abbreviated sonographic examination done in the emergency room can provide accurate, useful information about the presence of aneurysm; this procedure does not significantly delay triage of these patients. 相似文献
110.
The thinnest pair of slices provided by the EMI scanner is 8 mm, producing an overlap of 6 mm. Resolution is reduced by averaging the density of structures throughout the thickness of the slice. The authors described special collimators which provide thinner slices with no overlap and thereby improve the quality of orbital scans. 相似文献