全文获取类型
收费全文 | 745篇 |
免费 | 72篇 |
国内免费 | 6篇 |
专业分类
儿科学 | 20篇 |
妇产科学 | 2篇 |
基础医学 | 66篇 |
口腔科学 | 4篇 |
临床医学 | 95篇 |
内科学 | 188篇 |
皮肤病学 | 20篇 |
神经病学 | 90篇 |
特种医学 | 108篇 |
外科学 | 47篇 |
综合类 | 25篇 |
预防医学 | 58篇 |
药学 | 74篇 |
中国医学 | 1篇 |
肿瘤学 | 25篇 |
出版年
2019年 | 7篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 23篇 |
2012年 | 31篇 |
2011年 | 24篇 |
2010年 | 12篇 |
2009年 | 19篇 |
2008年 | 27篇 |
2007年 | 30篇 |
2006年 | 27篇 |
2005年 | 25篇 |
2004年 | 31篇 |
2003年 | 20篇 |
2002年 | 32篇 |
2001年 | 17篇 |
2000年 | 17篇 |
1999年 | 12篇 |
1998年 | 17篇 |
1997年 | 26篇 |
1996年 | 14篇 |
1995年 | 21篇 |
1994年 | 14篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 12篇 |
1990年 | 16篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 14篇 |
1986年 | 17篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 19篇 |
1976年 | 10篇 |
1975年 | 13篇 |
1974年 | 8篇 |
1973年 | 9篇 |
1972年 | 10篇 |
1971年 | 7篇 |
1970年 | 8篇 |
1969年 | 9篇 |
1967年 | 14篇 |
1966年 | 7篇 |
1965年 | 5篇 |
排序方式: 共有823条查询结果,搜索用时 15 毫秒
71.
父母物质滥用和精神疾病对青少年精神疾病的影响 总被引:2,自引:0,他引:2
目的:了解父母物质滥用和精神疾病对青少年精神疾病的影响.方法:研究对象为181名物质滥用青少年及其父母,调查了青少年精神疾病诊断情况并分析了父母物质滥用合并精神疾病对青少年精神疾病的影响.结果:父母对照组青少年和父母共患组青少年合并精神疾病诊断数分别为2.2±s 1.7和3.7±s 2.1(P<0.01),父母物质依赖合并精神疾病的青少年患广场恐怖伴惊恐发作、注意缺陷多动障碍(ADHD)、逆反性障碍的危险性分别是父母无物质依赖和精神疾病的青少年的5.0、2.4和4.1倍(P<0.05).结论:父母物质滥用合并精神疾病与青少年发生较多精神疾病有关,父母物质滥用合并精神疾病是青少年发生广场恐怖伴惊恐发作、ADHD和逆反性障碍的危险因素,需要加强相应评估和干预措施. 相似文献
72.
73.
74.
Effects of catecholamines and adrenergic-blocking agents on plasma and urinary cyclic nucleotides in man 总被引:6,自引:6,他引:6 下载免费PDF全文
John H. Ball Neil I. Kaminsky Joel G. Hardman Arthur E. Broadus Earl W. Sutherland Grant W. Liddle 《The Journal of clinical investigation》1972,51(8):2124-2129
Studies were performed in healthy volunteers to determine the effects of catecholamines and adrenergic-blocking agents on plasma and urinary levels of adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP).Plasma cyclic AMP rose in response to infusions of the beta-adrenergic agent, isoproterenol, or in response to infusions of either epinephrine or norepinephrine alone or in combination with the alpha-adrenergic-blocking agent, phentolamine. Although urinary cyclic AMP also rose, the percentage increase was less than that observed in the plasma. These treatments caused no increase in plasma cyclic GMP.Plasma cyclic GMP rose in response to infusions of alpha-adrenergic agents, viz., epinephrine or norepinephrine infused together with the beta-blocking agent, propranolol. These treatments caused no increase in plasma cyclic AMP.These observations are consistent with the current concept that the actions of beta-adrenergic agents are mediated by increases in cyclic AMP formation in target tissues. Such a mediating role has not been established for cyclic GMP, but the data suggest the possibility that cyclic GMP metabolism is responsive either to alpha-adrenergic stimulation or to parasympathetic stimulation which occurs as a reflexive consequence of the pressor effect of alpha-adrenergic agents. 相似文献
75.
76.
77.
78.
Superparamagnetic iron oxide: enhanced detection of focal splenic tumors with MR imaging 总被引:4,自引:0,他引:4
Weissleder R; Hahn PF; Stark DD; Elizondo G; Saini S; Todd LE; Wittenberg J; Ferrucci JT 《Radiology》1988,169(2):399-403
Superparamagnetic iron oxide (AMI-25), a reticuloendothelial cell-specific contrast agent for magnetic resonance (MR) imaging, was evaluated for its ability to permit detection of splenic metastases in 18 patients. Superparamagnetic iron oxide, at a dose of 30 mumol of iron per kilogram, decreased the signal intensity of spleen from 19.5 +/- 4.8 to 3.1 +/- 2.2 (spin-echo sequence, repetition time msec/echo time msec = 1,500/42; P less than .05), without changing the signal intensity of tumor. As a result, the tumor-spleen contrast-to-noise ratio increased from 0.2 (tumor isointense relative to spleen) to 18.0 (tumor hyperintense relative to spleen). As a consequence of increased contrast, splenic tumors were detected in four of 18 patients (45 individual lesions; P less than .05), whereas nonenhanced MR imaging permitted detection of splenic lesions in only two of 18 patients (four individual lesions). Maximum tumor-spleen contrast was achieved within 60 minutes after intravenous administration. These initial clinical results indicate that MR imaging with superparamagnetic iron oxide may offer improved accuracy in the diagnosis of splenic tumors. 相似文献
79.
Edelman RR; Hahn PF; Buxton R; Wittenberg J; Ferrucci JT; Saini S; Brady TJ 《Radiology》1986,161(1):125-131
The authors demonstrate that it is possible to obtain highly T1-weighted images of the abdomen using a suspended respiration partial saturation (SRPS) method in a breath-holding interval. T2*-weighted images, which reflect tissue T2 as well as variations in the static magnetic field, can also be rapidly obtained. The authors studied five healthy subjects and 19 patients with a variety of liver abnormalities, including benign and malignant hepatic neoplasms, fatty liver infiltration, ascites, and hematoma. On T1-weighted multisection acquisitions, the entire liver can be screened for mass lesions in a single 20-second breath-holding interval. Phase-contrast SRPS images are sensitive to fatty infiltration of the liver. SRPS images are more sensitive to variations in magnetic susceptibility than spin-echo images are, which has been proved to be of value in the detection of hemorrhage. With continued pulse sequence development and clinical study, this method has the potential to become the method of choice for evaluation of the upper abdomen. 相似文献
80.