全文获取类型
收费全文 | 3858篇 |
免费 | 189篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 66篇 |
妇产科学 | 122篇 |
基础医学 | 590篇 |
口腔科学 | 69篇 |
临床医学 | 259篇 |
内科学 | 1229篇 |
皮肤病学 | 70篇 |
神经病学 | 496篇 |
特种医学 | 183篇 |
外科学 | 371篇 |
综合类 | 28篇 |
一般理论 | 2篇 |
预防医学 | 157篇 |
眼科学 | 31篇 |
药学 | 204篇 |
中国医学 | 3篇 |
肿瘤学 | 137篇 |
出版年
2023年 | 27篇 |
2022年 | 53篇 |
2021年 | 112篇 |
2020年 | 40篇 |
2019年 | 68篇 |
2018年 | 89篇 |
2017年 | 59篇 |
2016年 | 59篇 |
2015年 | 93篇 |
2014年 | 115篇 |
2013年 | 134篇 |
2012年 | 235篇 |
2011年 | 288篇 |
2010年 | 155篇 |
2009年 | 161篇 |
2008年 | 241篇 |
2007年 | 235篇 |
2006年 | 218篇 |
2005年 | 206篇 |
2004年 | 176篇 |
2003年 | 151篇 |
2002年 | 145篇 |
2001年 | 37篇 |
2000年 | 32篇 |
1999年 | 36篇 |
1997年 | 20篇 |
1995年 | 21篇 |
1994年 | 14篇 |
1992年 | 20篇 |
1991年 | 20篇 |
1990年 | 26篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 23篇 |
1986年 | 25篇 |
1985年 | 18篇 |
1984年 | 14篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1975年 | 13篇 |
1933年 | 17篇 |
1932年 | 20篇 |
1931年 | 13篇 |
1930年 | 16篇 |
1928年 | 14篇 |
1922年 | 13篇 |
1908年 | 16篇 |
1907年 | 16篇 |
1906年 | 14篇 |
1902年 | 13篇 |
排序方式: 共有4065条查询结果,搜索用时 218 毫秒
1.
2.
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
3.
Ohne Zusammenfassung 相似文献
4.
Eduard Láng 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1872,1(5):425-431
Ohne Zusammenfassung
(Hierzu Tafel VIII.) 相似文献
5.
Ohne ZusammenfassungMit einer Tafel. 相似文献
6.
7.
8.
Ventilation imaging of the lung: Comparison of hyperpolarized helium-3 MR imaging with Xe-133 scintigraphy 总被引:1,自引:0,他引:1
Talissa A. Altes MD Patrice K. Rehm MD Frank Harrell PhD Michael Salerno PhD Thomas M. Daniel MD Eduard E. de Lange MD 《Academic radiology》2004,11(7):729-734
RATIONALE AND OBJECTIVES: To compare hyperpolarized helium-3 (HHe) magnetic resonance imaging (MRI) of the lung with standard Xe-133 lung ventilation scintigraphy. MATERIALS AND METHODS: We performed a retrospective review of 15 subjects who underwent HHe MRI and Xe-133 lung ventilation imaging. Coronal MRI sections were acquired after a single inhalation of HHe gas, and standard posterior planar lung ventilation scintigraphy was performed during continuous breathing of Xe-133 gas. The first breath scintigram of each patient was compared with a composite MR image composed of the sum of the individual MR images and with the individual helium-3 MR images. Ventilation defects on the two imaging modalities were compared for size, conspicuity, and concordance in presence and location. Assessment was done separately for each of four lung quadrants. RESULTS: Comparing the composite HHe MR images with Xe-133 scintigraphy, ventilation defect size, conspicuity and concordance were the same in 67% (40/60), 63% (38/60), and 62% (37/60) quadrants, respectively. Comparing the individual HHe MR image sections with the Xe-133 ventilation scan, there was concordance between the ventilation defects in 27% (16/60) of quadrants. More defects were identified on the individual HHe MR images in 62% (37/60) of quadrants. CONCLUSION: There was good agreement between composite HHe MR image and first breath Xe-133 scintigraphic images, supporting the widely held assumption that HHe MRI likely depicts first breath lung ventilation. 相似文献
9.
The 3-methoxy-4-hydroxyphenylglycol (MHPG) flow, the creatinine flow in 24 h urine and the plasma creatinine level were determined in 42 psychiatric control patients. The creatinine clearance was calculated. The relationship between MHPG flow in 24 h urine and creatinine clearance, creatinine flow, 24 h urinary output, age, sex and weight of the patient were studied by means of single and multiple regression methods. The MHPG flow was significantly correlated with creatinine clearance (r= 0.597), creatinine flow (r = 0.646) and sex of the patient (rpb = 0.434). The variance of the MHPG flow can be explained by the regression with creatinine flow, age and urinary output for at maximum 51.5%. These variables have to be taken into account for the interpretation of data concerning the MHPG flow in subsequent experimental designs. The results of the measurements of the MHPG flow can best be expressed as the residual values obtained after partialling out the predictable component calculated by multiple regression with creatinine flow, age and 24 h urine output. 相似文献
10.
Rene C. Bakker Eduard M. Scholten Johan W. de Fijter Leendert C. Paul 《Transplantation reviews (Orlando, Fla.)》2004,18(1):54-64
Although extensively studied, the pathophysiologic characteristics of chronic cyclosporine (CsA) nephrotoxicity are still far from being completely understood. The recognition of chronic CsA nephrotoxicity in allografted kidneys is hampered by a lack of easily assessable sensitive and specific markers. Long-term results of CsA withdrawal trials and trials that evaluated CsA sparing or withdrawal after the diagnosis of chronic allograft nephropathy (CAN) have shown that chronic CsA nephrotoxicity has a more important role in the etiology of late transplant dysfunction than appreciated before. Various hypotheses have explained the renal structural changes of chronic CsA nephrotoxicity including ischemia, cellular toxicity, and the stimulation of renal fibrosis by growth factors or cytokines. Possible ways to prevent chronic CsA nephrotoxicity include improved therapeutic drug monitoring and CsA withdrawal or avoidance. Patients with aspecific CAN in late biopsy may benefit from withdrawal of CsA or a reduction of its dose. Current knowledge is being discussed. It is concluded that in the near future more strategies are likely to be used to prevent loss of allograft function as a result of drug toxicity. 相似文献