全文获取类型
收费全文 | 12021篇 |
免费 | 956篇 |
国内免费 | 433篇 |
专业分类
耳鼻咽喉 | 41篇 |
儿科学 | 198篇 |
妇产科学 | 379篇 |
基础医学 | 382篇 |
口腔科学 | 73篇 |
临床医学 | 4716篇 |
内科学 | 1792篇 |
皮肤病学 | 80篇 |
神经病学 | 312篇 |
特种医学 | 654篇 |
外国民族医学 | 3篇 |
外科学 | 1426篇 |
综合类 | 2034篇 |
预防医学 | 303篇 |
眼科学 | 163篇 |
药学 | 364篇 |
4篇 | |
中国医学 | 60篇 |
肿瘤学 | 426篇 |
出版年
2024年 | 113篇 |
2023年 | 324篇 |
2022年 | 407篇 |
2021年 | 510篇 |
2020年 | 514篇 |
2019年 | 566篇 |
2018年 | 354篇 |
2017年 | 374篇 |
2016年 | 338篇 |
2015年 | 381篇 |
2014年 | 612篇 |
2013年 | 601篇 |
2012年 | 504篇 |
2011年 | 725篇 |
2010年 | 612篇 |
2009年 | 538篇 |
2008年 | 561篇 |
2007年 | 609篇 |
2006年 | 724篇 |
2005年 | 598篇 |
2004年 | 529篇 |
2003年 | 494篇 |
2002年 | 439篇 |
2001年 | 371篇 |
2000年 | 215篇 |
1999年 | 212篇 |
1998年 | 275篇 |
1997年 | 169篇 |
1996年 | 141篇 |
1995年 | 121篇 |
1994年 | 96篇 |
1993年 | 56篇 |
1992年 | 59篇 |
1991年 | 50篇 |
1990年 | 54篇 |
1989年 | 33篇 |
1988年 | 24篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 6篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1975年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Twelve cerebral lesions were operated upon with various laser sources (carbon dioxide, neodymium-yttrium-argon-garnet, and argon) and with an ultrasonic aspirator utilizing the intraoperative "real-time" ultrasonography. With the last method, the tumor was imaged just as well through the intact dura mater as on the brain surface itself, allowing a precise localization of deep intracranial lesions. A sharp selectivity on the healthy tissues is, in this way, achievable to reach the tumor, which is successively removed with the laser and ultrasonic aspirator checking the surgical maneuvers on the visual control of the ultrasonograph. 相似文献
72.
Summary Intraoperative spinal sonography (IOSS) was performed in 28 patients with extramedullary spinal tumours. Images were obtained of 31 tumours, because 2 patients had multiple tumours. There were 17 neurilemmomas, 9 meningiomas and 2 dermoid, cysts. All tumours appeared well-defined and highly echogenic. There was no difficulty differentiating extramedullary spinal tumours from intramedullary nasses excepting case, a big neurilemmoma at the conus medullaris. All images were assessed with reference to the surface of the lesions, the existence of cysts, and movement. Neurilemmomas had smooth surfaces, some cysts, and exhibited a floating movement. Meningiomas had irregular surfaces, were more highly echogenic than neurilemmomas, and adhered tightly to the dura mater. However, some neurilemmomas and meningiomas did not have these, and it was not always possible to differentiate them. Although, IOSS has limitations of resolution, it gave useful information about the size of the tumours, the degree of displacement of the spinal cord, and even about the type of tumour in some cases. It was extremely helpful to the surgeon. 相似文献
73.
超声测量胎儿LL/FSTT预测胎儿体重 总被引:2,自引:0,他引:2
目的:探讨应用B型超声测量胎儿肝脏长度与胎儿股骨皮下组织厚度的比值(LL/FSTT)预测胎儿出生体重的临床价值。方法:用B型超声对400例胎儿双顶径、头围、腹围、股骨长度、肝脏长度与股骨皮下组织的厚度进行测量并分析与新生儿出生体重的关系。结果;肝脏长度与股骨皮下组织厚度的比值和胎儿体重密切相关(r=0.901)。对正常胎儿体重、巨大儿、胎儿宫内发育迟缓(IUGR)诊断的敏感性分别是88%、89%、86%,特异性分别是90%、92%、88%。结论:用胎儿肝脏长度与股骨皮下软组织厚度的比值预测胎儿体重的方法简单、准确,为临床掌握分娩时机和分娩方式提供可靠参考数据。 相似文献
74.
Rachael McEwing Christina Hayward Margaret Furness 《Journal of Medical Imaging and Radiation Oncology》2003,47(2):101-110
Foetal abdominal cysts are frequently found on routine antenatal ultrasound. Various sonographic features might help in their differential diagnosis. However, a definitive diagnosis is often not made until postnatal life, and detection of an intra‐abdominal cyst antenatally rarely alters obstetric management. A review of possible causes of a foetal abdominal cyst is presented. 相似文献
75.
A case of adrenal cystic neuroblastoma (NB) detected by prenatal ultrasonography (US) is presented. The suprarenal mass initially
showed pure cystic features on a variety of imaging studies such as US, computed tomography, and magnetic resonance imaging.
Tumor markers were negative. The mass was suspected to be an adrenal hemorrhage rather than a NB. Three months later, although
the diameter was unchanged, the thickness of the cyst wall seemed to have slightly increased. Surgical exploration revealed
an adrenal cystic tumor and histology showed a NB in situ. Forty-five infants with prenatally detected NB were found in the
English literature; about one-half of them were cystic NBs, and most had a favorable outcome.
Accepted: 29 July 1996 相似文献
76.
目的 评价腔内超声(EU)对食管癌术前分期的准确性.方法30例食管癌患者术前进行EU(5MH_z直径 10mm)检查,其中8例(26.7%)因狭窄严重未能对肿瘤进行全面探测.全部患者均接受手术治疗,将术前临床分期.EU分期的结果与术后病理分期进行对比分析.结果 术前临床分期正确率仅为40%.EU对肿瘤外侵程度(T)、区域淋巴结受累情况(N)及术前分期的正确率在全组分别为76.7%、66.7%和70.0%,若去除严重狭窄病例后上升为77.7%、77.7%和77.3%.结论 EU能相当准确地对食管癌进行术前分期,提示肿瘤有无外侵或淋巴结转移,为治疗提供指导.病灶周围炎症反应、肿瘤微转移灶及严重狭窄是影响分期正确性的重要因素. 相似文献
77.
糖尿病患者下肢动脉管壁内膜-中层厚度的研究 总被引:4,自引:0,他引:4
目的 研究糖尿病与动脉硬化性血管障碍的关系。方法 对60例糖尿病患者及60例非糖尿病患者进行超声检查,两侧下肢动脉内径(D)、内膜-中层厚度(IMT)、收缩期最高速度(Max)、舒张期速度(Min)、搏动指数(PI)、阻力指数(RI)及有无斑块形成,进行统计。结果 IMT糖尿病组较非糖尿病组增厚(P〈0.01),各项血流参数在糖尿 且与非糖尿病组间差别无显著性(P〈0.05)。结论 下肢动脉的IM 相似文献
78.
腔内超声对直肠癌术前分期诊断的应用价值 总被引:6,自引:1,他引:6
目的:评价腔内超声(ELUS)对直肠癌术前分期诊断的准确性及局限性.方法:对58例直肠癌术前行ELUS检查,参考TNM分期标准进行术前分期诊断,并与手术及术后病理结果对照.结果:ELUS对58例直肠癌浸润深度诊断符合率达79.3%,T1、T2、T3、T4各期诊断灵敏度分别为100%、58.8%、87.5%、83.3%.对T2期诊断灵敏度最低,误诊7例中6例过深判断为T3期,且均为溃疡型腺癌.ELUS对54例直肠癌淋巴结转移诊断灵敏度、特异度、准确度分别为76.9%、75.0%、75.9%.淋巴结转移ELUS漏诊6例,淋巴结转移ELUS诊断假阳性7例.结论:ELUS对直肠癌浸润深度及肠周淋巴结转移诊断准确度较高,可成为直肠癌术前分期诊断良好的方法.对T2期的过深判断为影响诊断符合率的重要因素,肿瘤导致肠腔明显狭窄或肿瘤位于直肠上段也影响ELUS的准确性. 相似文献
79.
Intravascular ultrasound (IVUS) imaging provides useful additional information to X-ray angiography in selected cases of
balloon angioplasty and stent placement with complex vascular anatomy and unclear findings at angiography. It facilitates
accurate measurements of the vessel dimensions and reveals the extent of the disease for the selection of proper angioplasty
balloon size, as well as confirms full expansion and attachment of the stent or stent graft to the arterial wall. Intravascular
US imaging contributes useful information for the basis of planning surgical or endovascular therapy of aortic dissection
and is valuable for guiding percutaneous fenestration of the dissection flap. This imaging modality facilitates placement
of vena cava filter without cavography and/or fluoroscopy in patients with contraindication for iodine contrast media and/or
X-ray fluoroscopy. Technical development may further increase utility of IVUS imaging in interventional radiology.
Received: 22 May 2000; Accepted: 7 June 2000 相似文献
80.
127 patients with aneurysmal subarachnoid haemorrhage (SAH) were analyzed for the relationship between the amount of blood clots as detected by initial computed tomography (CT) up to 48 hours after SAH and changes of blood flow velocities as measured using transcranial Doppler ultrasonography (TCD). All patients were operated on within 72 hours after SAH. Patients who presented with remarkable brain oedema or with pathological intracranial pressure (ICP) due to mass effects of a haematoma, and who were in a poor neurological condition classified according to Hunt-Hess as grade V were excluded from this study. Serial TCD examination of the middle cerebral arteries (MCA) and anterior cerebral arteries (ACA) started within 48 hours after SAH and were performed daily up to three weeks. A statistically significant correlation between blood load designated according to Fisher's grading as group CT I-CT IV and mean flow velocities (MFV) was found in groups CT I, II, and III. High values of MFV in MCA examinations were noted in patients with severe SAH (group CT III)--161 cm/s, and low values in patients without SAH (group CT I)--119 cm/s. Patients with haematocephalus and/or haematoma without a mass effect (group CT IV) had lower blood flow velocities than patients with severe SAH (group CT III) but values were higher than in patients without SAH (group CT I). The number of days for which MFV in the MCA was > 120 cm/s and was statistically (p < 0.05) correlated with the amount of blood clots as observed in the respective CT (in group CT I, II, and III). MFV values in the anterior cerebral artery (ACA) were lower than those obtained in the middle cerebral artery (MCA) in all groups. Statistically significant (p < 0.05) differences were noted between groups CT I and CT III (first and third week) and between groups CT I and CT IV (third week). If the SAH was extensive in the CT scan, pathological values of MFV > 90 cm/s were observed in ACA, and this was more pronounced in group CT III than in group CT IV. Blood flow velocities obtained via TCD were registered to compare side-to-side differences and particularly high differences were observed in patients with severe SAH. It is concluded that the amount of blood clots in the initial computed tomography after SAH is significantly correlated with cerebral blood flow velocity measurements by TCD. 相似文献