全文获取类型
收费全文 | 94568篇 |
免费 | 9109篇 |
国内免费 | 2181篇 |
专业分类
耳鼻咽喉 | 707篇 |
儿科学 | 1280篇 |
妇产科学 | 629篇 |
基础医学 | 6176篇 |
口腔科学 | 1477篇 |
临床医学 | 17659篇 |
内科学 | 11050篇 |
皮肤病学 | 501篇 |
神经病学 | 12590篇 |
特种医学 | 26374篇 |
外国民族医学 | 20篇 |
外科学 | 6690篇 |
综合类 | 9461篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 1927篇 |
眼科学 | 1345篇 |
药学 | 3431篇 |
63篇 | |
中国医学 | 662篇 |
肿瘤学 | 3813篇 |
出版年
2024年 | 342篇 |
2023年 | 1699篇 |
2022年 | 3463篇 |
2021年 | 4416篇 |
2020年 | 4007篇 |
2019年 | 3729篇 |
2018年 | 3597篇 |
2017年 | 3812篇 |
2016年 | 3990篇 |
2015年 | 3962篇 |
2014年 | 6742篇 |
2013年 | 5993篇 |
2012年 | 5571篇 |
2011年 | 6041篇 |
2010年 | 5096篇 |
2009年 | 5258篇 |
2008年 | 5164篇 |
2007年 | 4868篇 |
2006年 | 4375篇 |
2005年 | 3819篇 |
2004年 | 3184篇 |
2003年 | 2548篇 |
2002年 | 2034篇 |
2001年 | 1893篇 |
2000年 | 1559篇 |
1999年 | 1235篇 |
1998年 | 1211篇 |
1997年 | 1137篇 |
1996年 | 996篇 |
1995年 | 850篇 |
1994年 | 724篇 |
1993年 | 578篇 |
1992年 | 446篇 |
1991年 | 336篇 |
1990年 | 253篇 |
1989年 | 188篇 |
1988年 | 160篇 |
1987年 | 140篇 |
1986年 | 102篇 |
1985年 | 88篇 |
1984年 | 66篇 |
1983年 | 45篇 |
1982年 | 42篇 |
1981年 | 25篇 |
1980年 | 29篇 |
1979年 | 17篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1971年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
目的 :探讨移动数字成像系统GE OECSeries 980 0进行经皮冠状动脉腔内成形术 (PTCA)的可行性和安全性。方法 :回顾分析 32例应用GE OECSeries 980 0X线机进行PTCA治疗冠心病的临床资料。结果 :①本组病例成功率为 90 6 % (2 9/ 32 ) ,血管成功率为 88 1% (37/ 4 2 ) ,病变成功率 83% (39/ 4 7)。成功病例狭窄由术前目测平均直径狭窄(92 8± 3 5 ) %减少到术后的 (6 5± 4 2 ) %。②AMI溶栓后补救性PTCA成功率高。结论 :应用GE OECSeries 980 0X线机能够满足心血管病区心脏介入治疗的需要 ,是安全可行的和具有良好的成本 效益比 相似文献
112.
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
113.
Role of intracortical mechanisms in the late part of the silent period to transcranial stimulation of the human motor cortex 总被引:3,自引:0,他引:3
J.P. Brasil-Neto A. Cammarota J. Valls-Solé A. Pascual-Leone M. Hallett L. G. Cohen 《Acta neurologica Scandinavica》1995,92(5):383-386
Transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the human motor cortex produce a silent period (SP) following motor evoked potentials (MEPs). The early part of the SP can be explained by decreased alpha motor neuron excitability, whereas the late part is presumably due to suprasegmental mechanisms. In order to determine the level of the suprasegmental contribution to the generation of SPs, we recorded excitatory and inhibitory responses to TMS, TES, and percutaneous electrical brainstem stimulation (PBS) in the voluntarily activated first dorsal interosseous muscle of the hand. Stimulus intensities were set so that PBS and TES induced MEPs with areas equal to or larger than those of MEPs obtained with TMS. This procedure revealed that SPs were 49% and 83% shorter with TES and PBS, respectively, than with TMS. As TMS is more effective than TES or PBS in activating cortical interneurons, these findings support the idea that a significant component of the SP arises from intracortical mechanisms. 相似文献
114.
Shoji Kubo Hiroaki Kinoshita Kazuhiro Hirohashi Takatsugu Yamamoto 《Journal of Hepato-Biliary-Pancreatic Surgery》1995,2(1):85-89
A case of cystadenocarcinoma of the liver is reported. The patient was a 73-year-old woman in whom a tumor was detected in
the lateral segment of the liver during a health examination. Ultrasonograms and computed tomograms showed a multilocular
cystic mass. Magnetic resonance imaging (MRI) showed a multilocular lowintensity mass, including a high-intensity portion
and a portal branch compressed by the tumor. MRI with gadolinium showed an enhanced cyst wall. The cystic part of the tumor
became smaller and the solid part became larger over a 1-month period, indicating that the tumor was malignant. Subsegmentectomy
(S3) was performed and cystadenocarcinoma with cystadenoma was diagnosed by histopathological examination. Identification of
changes in the appearance of a tumor should be helpful for the differential diagnosis of cystadenoma and cystadenocarcinoma. 相似文献
115.
Localized proton magnetic resonance spectroscopy of a cerebellar tumor in a two-year-old child 总被引:1,自引:0,他引:1
B. Wilken G. Helms H. J. Christen J. Bhnk J. Frahm F. Hanefeld 《Child's nervous system》1996,12(10):626-629
Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs. 相似文献
116.
Changes on serial assessments of brain MRI lesion load are used for monitoring therapeutic efficacy in patients with multiple
sclerosis (MS). We assessed the accuracy and reliability of conventional spin-echo (CSE) and fast spin-echo (FSE) sequences
for measurement of lesion volume using a semiautomated contour technique. Cranial CSE and FSE examinations of 18 patients
with secondary progressive MS were studied. The mean lesion load was slightly higher with the CSE sequence (p = 0.002). Intraobserver
variability was significantly higher for FSE than for CSE, according to both the coefficient of variation between two measurements
(mean 2.48 % and 1.35 % respectively, p < 0.05) and back-transformed 95 % limits of agreement (1.005–1.060 for FSE; 0.988–1.019
for CSE). Although FSE sequences are quicker and the total lesion volume measurements are similar to those obtained with CSE,
the poorer reproducibility raises doubts about the use of FSE to replace CSE in clinical trials.
Received: 26 March 1996 Accepted: 4 April 1996 相似文献
117.
A. Heinig S. H. Heywang-Köbrunner P. Viehweg D. Lampe J. Buchmann R. P. Spielmann 《Der Radiologe》1997,37(9):710-717
Summary
Early recognition of recurrence and work-up of clinically indeterminate lesions may be impaired after reconstruction with
silicone implants due to superimposition of the implant or to scarring. This study was undertaken to evaluate the use of contrast-enhanced
MRI in patients with silicone implant after breast cancer. Contrast-enhanded MRI was offered to 169 patients. Comparative
two- to three-view mammography was also performed in 169 patients, as well as comparative sonography in 144 patients. Conventional
imaging and clinical examination detected only 8/13 recurrences, whereas 12/13 were detected by MRI. One recurrence had been
visible as a strongly enhancing 2-mm dot in a previous examination (2 years before), but was not called. It was therefore
counted as false negative. In addition, multicentricity was detected by MRI alone in two of three cases. MRI correctly diagnosed
scar tissue in all cases with indeterminate findings. However, due to false-positive calls caused by enhancing granulomas
specificity could not be improved. Contrast-enhanded MRI allowed decisive additional information in our study group and improved
the sensitivity significantly (concerning all diagnoses). Contrast-enhanded MRI is recommended in patients with diagnostic
problems or high risk of recurrence after silicone implants.
相似文献
118.
目的 探讨各种脑膜病变脑膜MRI强化类型与病因的关系。方法 回顾性分析78例资料完整,MRI增强扫描脑膜异常强化的非脑膜瘤。结果 78例中,脑膜癌病16例(硬脑膜-蛛网膜型2例,软脑膜-蛛网膜下腔型11例,混合型3例);感染性脑膜炎18例(硬脑膜-蛛网膜型3例,软脑膜-蛛网膜下腔型13例,混合型2例);脑梗死22例(软脑膜-蛛网膜下腔型18例,混合型4例);开颅术后15例(硬脑膜-蛛网膜型10例,混合型5例);硬膜下积液(血肿)7例,均为硬脑膜-蛛网膜型。结论 MRI双倍剂量Gd-DTPA增强扫描对脑膜病变敏感性高,脑膜强化类型与各种病因侵犯脑膜三层结构的方式和程度有关。 相似文献
119.
Summary Two contrasting cases of cervical intramedullary cavernous angioma in young female patients are reported. One patient had a 3-year course of step-wise progressive tetraparesis; at each of the five events intramedullary bleeding from a cryptic vascular malformation at C6–7 level was diagnosed by MRI. The other patient presented with one episode which led to MRI diagnosis of a vascular malformation at the C2 level. Both patients eventually underwent complete surgical excision of the angioma with subsequent steady improvement of the neurological deficit. 相似文献
120.
椎动脉型颈椎病的影像学诊断 总被引:2,自引:0,他引:2
本文描述了椎动脉型颈椎病的概念及发病机制 ,并对该病的各种影像学检查的主要表现及优缺点进行了综述。 相似文献