全文获取类型
收费全文 | 1364篇 |
免费 | 128篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 58篇 |
妇产科学 | 23篇 |
基础医学 | 206篇 |
口腔科学 | 20篇 |
临床医学 | 121篇 |
内科学 | 239篇 |
皮肤病学 | 88篇 |
神经病学 | 110篇 |
特种医学 | 101篇 |
外科学 | 167篇 |
综合类 | 15篇 |
预防医学 | 117篇 |
眼科学 | 22篇 |
药学 | 58篇 |
肿瘤学 | 138篇 |
出版年
2023年 | 10篇 |
2022年 | 19篇 |
2021年 | 29篇 |
2020年 | 23篇 |
2019年 | 15篇 |
2018年 | 54篇 |
2017年 | 30篇 |
2016年 | 39篇 |
2015年 | 46篇 |
2014年 | 58篇 |
2013年 | 65篇 |
2012年 | 111篇 |
2011年 | 122篇 |
2010年 | 63篇 |
2009年 | 56篇 |
2008年 | 78篇 |
2007年 | 78篇 |
2006年 | 90篇 |
2005年 | 107篇 |
2004年 | 64篇 |
2003年 | 69篇 |
2002年 | 61篇 |
2001年 | 10篇 |
2000年 | 16篇 |
1999年 | 20篇 |
1998年 | 17篇 |
1997年 | 16篇 |
1996年 | 12篇 |
1995年 | 3篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1984年 | 5篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1977年 | 2篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1970年 | 5篇 |
1969年 | 4篇 |
1968年 | 6篇 |
1967年 | 4篇 |
1966年 | 3篇 |
1965年 | 3篇 |
1964年 | 3篇 |
排序方式: 共有1502条查询结果,搜索用时 15 毫秒
1.
Very preterm children are at increased risk of reduced processing speed at 5 years of age,predicted by typical complications of prematurity and prenatal smoking 下载免费PDF全文
2.
Digital radiography is an appropriate method for both bedside and in-department chest radiographs. Its major advantage in bedside chest radiography is its control of the displayed optical density of these radiographs. With dynamic range control processing, it improves the visibility of tubes and lines superimposed on the mediastinal tissues. When used for in-department chest radiography, it may offer slight advantages in the evaluation of disease in the mediastinum, but in general is equivalent to film-screen chest radiography. The main reasons for using digital chest radiography for in-department chest radiographs relate mainly to its use as a data entry point method of projection radiography for high-quality teleradiology or for its use in a picture archiving and communication system. Apart from these advantages, there is no reason to change from conventional to digital chest radiographs. Digital radiographs are, with certain systems, printed at smaller than life size. Because of this, there is a necessary period of learning as radiologists adjust to the new image size. The most important change in radiologists' work pattern appears to be the need to sit closer to the film. Findings of disease are smaller, but, with experience, just as easy to see. 相似文献
3.
Sibylle von Vietinghoff Wolfgang Schneider Friedrich C Luft Ralph Kettritz 《Nephrology, dialysis, transplantation》2006,21(11):3324-3326
4.
Image processing is a critical part of obtaining high-quality digital radiographs. Fortunately, the user of these systems does not need to understand image processing in detail, because the manufacturers provide good starting values. Because radiologists may have different preferences in image appearance, it is helpful to know that many aspects of image appearance can be changed by image processing, and a new preferred setting can be loaded into the computer and saved so that it can become the new standard processing method.Image processing allows one to change the overall optical density of an image and to change its contrast. Spatial frequency processing allows an image to be sharpened, improving its appearance. It also allows noise to be blurred so that it is less visible. Care is necessary to avoid the introduction of artifacts or the hiding of mediastinal tubes. 相似文献
5.
Planning the aesthetic foreheadplasty 总被引:1,自引:0,他引:1
Different approaches to aesthetic foreheadplasty have been thoroughly described and well documented. However, there has been a paucity of information in the literature describing indications for the various approaches. We detail our approach to planning the foreheadplasty; most commonly, we opt for the anterior forehead-hairline approach. We believe that proper patient selection with regard to anatomical, aesthetic, and physiological factors is of the greatest importance in planning an aesthetic foreheadplasty. 相似文献
6.
Takahiro Higuchi Stephan G Nekolla Antanas Jankaukas Axel W Weber Marc C Huisman Sybille Reder Sibylle I Ziegler Markus Schwaiger Frank M Bengel 《Journal of nuclear medicine》2007,48(2):288-294
The combination of small-animal PET and MRI data provides quantitative in vivo insights into cardiac pathophysiology, integrating information on biology and morphology. We sought to determine the feasibility of PET and MRI for the quantification of ischemic injury in the rat model. METHODS: Fourteen healthy male Wistar rats were studied with 18F-FDG PET and cine MRI. Myocardial viability was determined in a transmural myocardial infarction model in 12 additional rats, using 18F-FDG PET and delayed-enhancement MRI with gadolinium-diethylenetriaminepentaacetic acid. All PET was acquired with a dedicated small-animal PET system. MRI was performed on a 1.5-T clinical tomograph with a dedicated small-animal electrocardiographic triggering device and a small surface coil. RESULTS: In normal rats, 18F-FDG uptake was homogeneous throughout the left ventricle. The lowest mean uptake of the 18F-FDG was found in the apical regions (79% +/- 6.0% of maximum) and the highest uptake was in the anterior wall (93% +/- 4.3 % of maximum). Myocardial infarct size as determined by histology correlated well with defects of glucose metabolism obtained with 18F-FDG PET (r = 0.89) and also with delayed-enhancement MRI (r = 0.91). Left ventricular ejection fraction in normal rats measured by cine MRI was 57% +/- 5.4% and decreased to 38% +/- 12.9% (P < 0.001) in the myocardial infarction model. CONCLUSION: Integrating information from small-animal PET and clinical MRI instrumentation allows for the quantitative assessment of cardiac function and infarct size in the rat model. The MRI measurements of scar can be complemented by metabolic imaging, addressing the extent and severity of ischemic injury and providing endpoints for therapeutic interventions. 相似文献
7.
8.
Jürgen Schneider-Schaulies Volker ter Meulen Sibylle Schneider-Schaulies 《Journal of neurovirology》2003,9(2):247-252
Central nervous system (CNS) complications occurring early and late after acute measles are serious and often fatal. In spite of functional cell-mediated immunity and high antiviral antibody titers, an immunological control of the CNS infection is not achieved in patients suffering from subacute sclerosing panencephalitis (SSPE). The known cellular receptors for measle virus (MV) in humans, CD46 and CD150 (signaling lymphocyte activation molecule, SLAM), are important components of the viral tropism by mediating binding and entry to peripheral cells. Because neural cells do not express SLAM and only sporadically CD46, virus entry to neural cells, and spread within the CNS, remain mechanistically unclear. Mice, hamsters, and rats have been used as model systems to study MV-induced CNS infections, and revealed interesting aspects of virulence, persistence, the immune response, and prerequisites of protection. With the help of recombinant MV and mice expressing transgenic receptors, questions such as receptor-dependent viral spread, or viral determinants of virulence, have been investigated. However, many questions concerning the human MV-induced CNS diseases are still open. 相似文献
9.
Marika A. Artz Johannes M. M. Boots Gerry Ligtenberg Joke I. Roodnat Maarten H. L. Christiaans Pieter F. Vos Philip Moons George Borm Luuk B. Hilbrands 《American journal of transplantation》2004,4(6):937-945
Long-term use of cyclosporine after renal transplantation results in nephrotoxicity and an increased cardiovascular risk profile. Tacrolimus may be more favorable in this respect. In this randomized controlled study in 124 renal transplant patients, the effects of conversion from cyclosporine to tacrolimus on renal function, cardiovascular risk factors, and perceived side-effects were investigated after a follow-up of 2 years. After conversion from cyclosporine to tacrolimus renal function remained stable, whereas continuation of cyclosporine was accompanied by a rise in serum creatinine from 142 +/- 48 micromol/L to 157 +/- 62 micromol/L (p < 0.05 comparing both groups). Conversion to tacrolimus resulted in a sustained reduction in systolic and diastolic blood pressure, and a sustained improvement in the serum lipid profile, leading to a reduction in the Framingham risk score from 5.7 +/- 4.3 to 4.8 +/- 5.3 (p < 0.05). Finally, conversion to tacrolimus resulted in decreased scores for occurrence of and distress due to side-effects. In conclusion, conversion from cyclosporine to tacrolimus in stable renal transplant patients is beneficial with respect to renal function, cardiovascular risk profile, and side-effects. Therefore, for most renal transplant patients tacrolimus will be the drug of choice when long-term treatment with a calcineurin inhibitor is indicated. 相似文献
10.
Kaindl AM Jakubiczka S Lücke T Bartsch O Weis J Stoltenburg-Didinger G Aksu F Oexle K Koehler K Huebner A 《Human mutation》2005,26(3):279-280
Microdeletion syndromes are commonly transmitted as dominant traits and are frequently associated with variably expressed pleiotropic phenotypes. Nonlethal homozygous microdeletions, on the other hand, are very rare. Here, we delineate the fifth and so far largest homozygous microdeletion in nonmalignancies of approximately 400 kb on chromosome 4q11-q12 in a large consanguineous East-Anatolian family with six affected patients. The deleted region contains the beta-sarcoglycan gene (SGCB), the predicted gene SPATA18 (spermatogenesis associated 18 homolog) and several expressed sequence tags. Patients presented with a severe and progressive Duchenne-like muscular dystrophy phenotype, a combination of hyperlaxity and joint contractures, chest pain, palpitations, and dyspnea. 相似文献