全文获取类型
收费全文 | 2994358篇 |
免费 | 236566篇 |
国内免费 | 5155篇 |
专业分类
耳鼻咽喉 | 43508篇 |
儿科学 | 89154篇 |
妇产科学 | 78637篇 |
基础医学 | 422785篇 |
口腔科学 | 88152篇 |
临床医学 | 270543篇 |
内科学 | 584505篇 |
皮肤病学 | 61407篇 |
神经病学 | 247305篇 |
特种医学 | 119167篇 |
外国民族医学 | 941篇 |
外科学 | 461670篇 |
综合类 | 68288篇 |
现状与发展 | 2篇 |
一般理论 | 1156篇 |
预防医学 | 232789篇 |
眼科学 | 70601篇 |
药学 | 227373篇 |
7篇 | |
中国医学 | 5868篇 |
肿瘤学 | 162221篇 |
出版年
2018年 | 29801篇 |
2016年 | 25516篇 |
2015年 | 28893篇 |
2014年 | 41197篇 |
2013年 | 62334篇 |
2012年 | 84233篇 |
2011年 | 88811篇 |
2010年 | 52372篇 |
2009年 | 50163篇 |
2008年 | 84978篇 |
2007年 | 90077篇 |
2006年 | 91435篇 |
2005年 | 88995篇 |
2004年 | 85801篇 |
2003年 | 82700篇 |
2002年 | 81615篇 |
2001年 | 145845篇 |
2000年 | 151090篇 |
1999年 | 127565篇 |
1998年 | 34951篇 |
1997年 | 31551篇 |
1996年 | 31371篇 |
1995年 | 30174篇 |
1994年 | 28329篇 |
1993年 | 26310篇 |
1992年 | 101949篇 |
1991年 | 98364篇 |
1990年 | 95015篇 |
1989年 | 91945篇 |
1988年 | 84998篇 |
1987年 | 83384篇 |
1986年 | 78825篇 |
1985年 | 75373篇 |
1984年 | 56242篇 |
1983年 | 47960篇 |
1982年 | 28005篇 |
1981年 | 24827篇 |
1980年 | 23207篇 |
1979年 | 52144篇 |
1978年 | 36248篇 |
1977年 | 30773篇 |
1976年 | 28309篇 |
1975年 | 30243篇 |
1974年 | 37201篇 |
1973年 | 35288篇 |
1972年 | 33189篇 |
1971年 | 30868篇 |
1970年 | 29085篇 |
1969年 | 27222篇 |
1968年 | 24713篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
A. Al Tahan S. Arora A. Alzeer F. Al Tahan T. Malabarey A. Daif 《European journal of neurology》1997,4(1):52-58
The diagnosis of acute disseminated encephalomyelitis (ADEM) is frequently missed or delayed with consequent delay in instituting therapy in the crucial phase of the illness. The role of MRI in the diagnosis of ADEM is well established, however, the value of its early utilization of treatment on the outcome of patients has not been adequately stressed. Three patients with ADEM are described. Delay in the diagnosis of the first was associated with severe sequelae, while in the other two early diagnosis and institution of corticosteroid therapy which was facilitated by MRI, was associated with a better outcome. MRI should be carried out early once the diagosis of ADEM is entertained. 相似文献
982.
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
983.
The value of ultrasound in the diagnosis of a large rapidly growing thyroid mass was assessed in a study of 42 patients with a large (> 3 cm) rapidly growing (< two months) solitary mass. Haemorrhage into a thyroid nodule was present in 31 patients and thyroid malignancy in 11. Ultrasound of haemorrhage into a thyroid nodule revealed a large cystic mass in all 31 patients containing internal debris (22), septations (three), or a combination of both (six). The malignant causes of a large rapidly growing mass were lymphoma (two), anaplastic carcinoma (four) and metastasis (five). Ultrasound of these thyroid malignancies revealed a mass with a smooth, well-defined margin and strikingly low homogeneous echogenicity in all cases. Patients with thyroid metastases had evidence of widespread metastatic disease elsewhere. Lymphoma was differentiated from anaplastic carcinoma on fine-needle aspiration cytology or surgical biopsy. Ultrasound was of value in differentiating between a benign haemorrhagic nodule and a malignant tumour. The various malignant tumours had similar appearances, however, and could not be distinguished on ultrasound. 相似文献
984.
糖耐量试验对评价肝癌患者肝脏储备功能的价值 总被引:5,自引:0,他引:5
绝大多数肝细胞性肝癌患者合并肝硬变,为预测其对肝切除的耐受性,给正确选择切肝患者提供依据,作者对62例切肝者和49例未切肝者手术前后的糖耐量试验(OGTT)和肝组织病理学进行了对比研究。结果:术前OGTT曲地P型者切肝后恢复顺利;L型者对肝切的耐受性差,术后易发生肝功能衰竭等并发症,其肝硬化和蔼多为CⅢ或CⅣ级,曲线形态界于P和L型之间的I型患者29例用肝门区域血管阻断法切肝,并在阻断血管前使用预 相似文献
985.
J Grogan B H Nowicki T A Schmidt V M Haughton 《AJNR. American journal of neuroradiology》1997,18(7):1325
PURPOSETo study the relationship of lumbar facet joint tropism to degeneration of the cartilage and subcortical bone in the facet joints and the effect of tropism in intervertebral disk degeneration.METHODSThe orientation of 104 cadaveric lumbar facet joints with respect to sagittal plane was measured on CT scans, and the joints were classified as having no tropism, mild tropism, or severe tropism. On MR images, the severity of cartilage degeneration and bony sclerosis was measured. The correlation between tropism and degeneration was calculated, as was the relationship among age, spinal level, and degeneration.RESULTSWe identified four spinal levels with severe tropism, six with moderate tropism, and 94 without tropism. Cartilage degeneration was not significantly more severe in the joints with tropism than in the joints without. Sclerosis was slightly greater in the joints with tropism than in the joints without it. Sclerosis and cartilage degeneration were significantly related to age and spinal level.CONCLUSIONAge, spinal level, and overall facet joint angle are more important factors in facet joint degeneration than is tropism. 相似文献
986.
987.
Therapeutic Consequences of Variation in Intraarterial Pressure Measurements After Iliac Angioplasty
Eric Tetteroo Cees Haaring Andries D. van Engelen Yolanda van der Graaf Willem P.T.M. Mali 《Cardiovascular and interventional radiology》1997,20(6):426-430
Purpose: To assess the accuracy of intraarterial measurement of transstenotic pressure gradients for the detection of hemodynamically
suboptimal iliac angioplasty.
Methods: In 14 patients, referred for diagnostic angiography, mean pressure gradients in the aorta and iliac artery were obtained
twice, using a double-sensor pressure catheter. Additional iliac measurements were performed during pharmacologically induced
flow augmentation. Repeatability was assessed by calculation of the mean difference plus standard deviation (MD ± SD) and
repeatability coefficient (2 × SD). These results were extrapolated to 137 iliac angioplasty procedures with secondary stenting
where there was a residual pressure gradient > 10 mmHg.
Results: MD ± SD for repeated measurements at rest and during flow augmentation were 0 ± 2 mmHg and 1 ± 3 mmHg, respectively. Repeatability
coefficients were 3 and 6 mmHg. Mean pressure gradients after hemodynamically insufficient angioplasty were 8 ± 7 mmHg at
rest and 17 ± 5 mmHg following vasodilatation. Inaccurate pressure recordings may have led to inappropriate stent placement
in less than 2.5%, and inappropriate denial of stent placement in less than 5% of the lesions.
Conclusion: Variability of intraarterial pressure measurements has little consequence in the detection of hemodynamically significant
stenosis after angioplasty.
Received: 0/00/00/Accepted: 0/00/00 相似文献
988.
989.
Cytologic evaluation of the CSF is often difficult when trying to distinguish between truly neoplastic and reactive cells. Several non-neoplastic conditions may be associated with atypical cells in the CSF, a fact the clinician has to consider to avoid inadequate aggressive theraphies. We report here three patients with infectious meningitis (due to Herpes zoster virus in two, and neuroborreliosis in one) and cytologically atypical cerebrospinal fluid lymphocytes. Further characterization showed that the pleocyrosis in these patients was of reactive origin. Cytomorphology is frequently insufficient and histochemical, immuncytochemical and cellular genome analysis techniques may help differentiate atypical reactive cells from neoplastic cells. 相似文献
990.