全文获取类型
收费全文 | 21972篇 |
免费 | 1885篇 |
国内免费 | 237篇 |
专业分类
耳鼻咽喉 | 219篇 |
儿科学 | 736篇 |
妇产科学 | 549篇 |
基础医学 | 3085篇 |
口腔科学 | 483篇 |
临床医学 | 2081篇 |
内科学 | 4436篇 |
皮肤病学 | 578篇 |
神经病学 | 1689篇 |
特种医学 | 760篇 |
外国民族医学 | 1篇 |
外科学 | 2610篇 |
综合类 | 971篇 |
一般理论 | 20篇 |
预防医学 | 1924篇 |
眼科学 | 497篇 |
药学 | 1451篇 |
7篇 | |
中国医学 | 423篇 |
肿瘤学 | 1574篇 |
出版年
2022年 | 180篇 |
2021年 | 343篇 |
2020年 | 232篇 |
2019年 | 260篇 |
2018年 | 342篇 |
2017年 | 255篇 |
2016年 | 287篇 |
2015年 | 379篇 |
2014年 | 497篇 |
2013年 | 687篇 |
2012年 | 1016篇 |
2011年 | 1047篇 |
2010年 | 626篇 |
2009年 | 637篇 |
2008年 | 947篇 |
2007年 | 980篇 |
2006年 | 922篇 |
2005年 | 882篇 |
2004年 | 755篇 |
2003年 | 753篇 |
2002年 | 751篇 |
2001年 | 699篇 |
2000年 | 749篇 |
1999年 | 583篇 |
1998年 | 260篇 |
1997年 | 222篇 |
1996年 | 196篇 |
1995年 | 219篇 |
1994年 | 183篇 |
1993年 | 193篇 |
1992年 | 502篇 |
1991年 | 506篇 |
1990年 | 445篇 |
1989年 | 457篇 |
1988年 | 421篇 |
1987年 | 439篇 |
1986年 | 415篇 |
1985年 | 397篇 |
1984年 | 365篇 |
1983年 | 251篇 |
1982年 | 169篇 |
1980年 | 199篇 |
1979年 | 269篇 |
1978年 | 218篇 |
1977年 | 174篇 |
1976年 | 181篇 |
1975年 | 175篇 |
1974年 | 218篇 |
1973年 | 204篇 |
1972年 | 171篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
多级图像对比度放大技术在膝关节摄影中的应用 总被引:1,自引:0,他引:1
目的:分析评价膝关节摄影中多级图像对比度放大技术(MUSICA)参数设定的成像效果,为实际临床应用提供理论指导。方法:随机抽取膝关节侧位软拷贝图像70例,以骨皮质、骨小梁、肌间隙、髌上囊、皮下脂肪为比对目标,由三位观察者对其显示情况进行分析,并对结果进行统计分析。结果:MUSICA处于较小值(0~2)时,适合于软组织显示,但图像锐利度欠缺;处于较高值时(4~6)适合于观察骨皮质、小梁等细节信息,但较多地出现伪影,共25例;处于2~4时整体影像对比度适中,如实反映人体密度结构。结论:作图像处理时应将MUSICA为2~4设定为常规,实际应用通常情况下可以选择该处理方法,但应根据具体要求适当调整MUSICA参数值。 相似文献
12.
13.
Leslee J. Shaw Romalisa Miranda-Peats Piotr Slomka John Friedman Sean W. Hayes Daniel S. Berman Gary V. Heller Marcin Dada William E. Boden Paul Casperson Robert A. O’Rourke Ronald Schwartz William S. Weintraub David J. Maron Spencer King Koon Teo Pamela Hartigan 《Journal of nuclear cardiology》2006,13(5):685-698
Background Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after
intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical
outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial.
Methods and Results The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical
therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been
designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia
at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship
between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate
the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization
patients. Substudy 2 (n _ 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic
intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive
risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization
in reducing patients’ ischemic burdens.
Conclusions The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology.
We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based
management of patients with stable coronary disease.
The COURAGE trial was supported by the Cooperative Studies Program of the Department of Veterans Affairs Office of Research
and Development in collaboration with the Canadian Institutes of Health Research. Unrestricted research grants were obtained
from Merck & Co; Pfizer Pharmaceuticals; Bristol-Myers Squibb Medical Imaging; Astellas Pharma; Kos Pharmaceuticals; Data
Scope; Astra Zeneca Pharmaceuticals; Astra-Zeneca-Canada; Schering-Plough Coorporation, Ltd; Sanofi-Aventis, Inc; First Horizon;
and GE Healthcare. All industrial funding for this trial was directed through the Department of Veterans Affairs. Additional
funding for this substudy was provided by grants to the Department of Veterans Affairs and Canadian Institutes of Health Research
from Astellas Pharma and Bristol-Myers-Squibb Medical Imaging. 相似文献
14.
J A Gottridge B R Meyer N S Schwartz R S Lesser 《Archives of internal medicine》1989,149(7):1660-1662
To determine the value of chest roentgenograms in the management of asymptomatic persons with positive tuberculin skin test results, we undertook a retrospective review of all tests administered by our Employee Health Service, North Shore University Hospital, Manhasset, NY, between July 1, 1983 and November 1, 1987. Of 5200 tests, 247 results were positive. Two hundred twenty-one of these charts were reviewed for roentgenographic results and the presence of symptoms. All persons were asymptomatic. Chest roentgenograms revealed the following: normal, 188; unrelated abnormalities, 24; apical pleural thickening, 5; granulomas, 2; calcified hilar node, 1; and calcified node plus granuloma, 1. We noted no active tuberculosis, nor did the chest roentgenographic results influence recommendations for isoniazid prophylaxis. We conclude that chest roentgenograms are of value in 0% to 1.3% of asymptomatic people with positive tuberculin test results. A larger study should be undertaken to further define the usefulness of chest roentgenograms in this population. 相似文献
15.
以链脲佐菌素制备糖尿病大鼠模型,造模后以还原型谷胱甘肽(GSH)治疗12周,结果显示GSH治疗组较糖尿病组心肌组织病理学损害改善,NF—κB活性降低,诱导型一氧化氮合酶表达下降。 相似文献
16.
17.
Oren S Cohen Eli Vakil David Tanne Zeev Nitsan Roseline Schwartz Sharon Hassin-Baer 《Cognitive and behavioral neurology》2007,20(1):68-72
OBJECTIVES: To test a possible association between the educational level (EL), cognitive performance, and neuropsychiatric features in Parkinson disease (PD). BACKGROUND: An inverse association has been reported between EL and cognitive dysfunction in patients with senile dementia of Alzheimer type but it is yet unsettled whether education has a similar effect on cognition in PD. METHODS: Seventy-two PD patients (45 males, mean age 68.7+/-11.6 y) underwent a detailed neurologic examination, a battery of neuropsychologic tests, and questionnaires for the evaluation of psychosis, sleep disturbances, and depression. According to the number of educational years, patients were divided into 3 groups: low EL (0 to 8 y), (15 patients), intermediate EL (9 to 12 y) (28 patients), and high EL (>/=13 y) (29 patients). RESULTS: Patients with a higher EL had a better cognitive function and an association was found between the patients' EL and their scores in various neuropsychologic tests mainly those sensitive to frontal lobe dysfunction. Low education was associated with an increased risk for hallucinations and a trend for more depression, delusions, and sleep disturbances. CONCLUSIONS: The association between high educational attainment and the lower risk of cognitive dysfunction suggest that education might modulate cognitive performance in PD. 相似文献
18.
19.
20.