全文获取类型
收费全文 | 46275篇 |
免费 | 2513篇 |
国内免费 | 697篇 |
专业分类
耳鼻咽喉 | 376篇 |
儿科学 | 636篇 |
妇产科学 | 125篇 |
基础医学 | 1917篇 |
口腔科学 | 1161篇 |
临床医学 | 5090篇 |
内科学 | 6114篇 |
皮肤病学 | 113篇 |
神经病学 | 2130篇 |
特种医学 | 10652篇 |
外国民族医学 | 12篇 |
外科学 | 3481篇 |
综合类 | 9230篇 |
现状与发展 | 1篇 |
预防医学 | 1994篇 |
眼科学 | 1549篇 |
药学 | 2105篇 |
44篇 | |
中国医学 | 507篇 |
肿瘤学 | 2248篇 |
出版年
2024年 | 91篇 |
2023年 | 587篇 |
2022年 | 1328篇 |
2021年 | 1697篇 |
2020年 | 1553篇 |
2019年 | 1303篇 |
2018年 | 1429篇 |
2017年 | 1422篇 |
2016年 | 1408篇 |
2015年 | 1280篇 |
2014年 | 2895篇 |
2013年 | 2492篇 |
2012年 | 2462篇 |
2011年 | 3028篇 |
2010年 | 2655篇 |
2009年 | 2827篇 |
2008年 | 2575篇 |
2007年 | 2628篇 |
2006年 | 2295篇 |
2005年 | 1850篇 |
2004年 | 1465篇 |
2003年 | 1380篇 |
2002年 | 1291篇 |
2001年 | 1032篇 |
2000年 | 843篇 |
1999年 | 704篇 |
1998年 | 630篇 |
1997年 | 547篇 |
1996年 | 427篇 |
1995年 | 463篇 |
1994年 | 389篇 |
1993年 | 261篇 |
1992年 | 237篇 |
1991年 | 182篇 |
1990年 | 166篇 |
1989年 | 155篇 |
1988年 | 127篇 |
1987年 | 137篇 |
1986年 | 124篇 |
1985年 | 218篇 |
1984年 | 181篇 |
1983年 | 81篇 |
1982年 | 152篇 |
1981年 | 142篇 |
1980年 | 112篇 |
1979年 | 80篇 |
1978年 | 66篇 |
1977年 | 47篇 |
1976年 | 21篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Computed tomography (CT) scans are often used for postoperative imaging in orthopedics. In the presence of metallic hardware, artifacts are generated, which can hamper visualization of the CT images, and also render the study ineffective for 3-D printing. Various solutions are available to minimize metal artifacts, and radiologists can employ these before or after processing the CT study. However, the orthopedic surgeon may be faced with situations where the metal artifacts were not addressed. To counter such problems, we present three do-it-yourself (DIY) techniques that can be used to manage metal artifacts. 相似文献
92.
Bert van Rietbergen Emmanuel Biver Thierry Chevalley Keita Ito Roland Chapurlat Serge Ferrari 《Journal of bone and mineral research》2021,36(7):1351-1363
During aging, changes in endosteal and periosteal boundaries of cortical bone occur that differ between men and women. We here develop a new procedure that uses high-resolution peripheral quantitative CT (HR-pQCT) imaging and 3D registration to identify such changes within the timescale of longitudinal studies. A first goal was to test the sensitivity of the approach. A second goal was to assess differences in periosteal/endosteal expansion over time between men and women. Rigid 3D registration was used to transform baseline and all follow-up (FU) images to a common reference configuration for which the region consisting of complete slices (largest common height) was determined. Periosteal and endosteal contours were transformed to the reference position to determine the net periosteal and endosteal expansion distances. To test the sensitivity, images from a short-term reproducibility study were used (15 female, aged 21 to 47 years, scanned three times). To test differences between men and women, images from a subset of the Geneva Retirees Cohort were used (248 female, 61 male, average age 65 years, 3.5 and 7 years FU). The sensitivity study indicated a least significant change for detecting periosteal/endosteal expansion of 41/31 microns for the radius and 17/26 microns for the tibia. Results of the cohort study showed significant net endosteal retraction only in females at the radius and tibia after 3.5 years (38.0 and 38.4 microns, respectively) that further increased at 7 years FU (70.4 and 70.8 microns, respectively). No significant net periosteal changes were found for males or females at 7 years. The results demonstrate that it is possible to measure changes in endosteal contours in longitudinal studies within several years. For the investigated cohort, significant endosteal retraction was found in females but not in males. Whether these changes in cortical geometry are related to fracture risk remains to be investigated in larger cohorts © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). 相似文献
93.
正多数下肢动脉栓塞病人在急性期内(发病6~8 h以内)行手术治疗可取得较好的治疗效果,但部分病人可能因医疗条件或个人原因而选择保守治疗(如仅使用抗凝药物等),下肢动脉部分开放或仅侧支开放,将疾病由急性期拖入了亚急性期,此时的血栓机化,并且与血管内膜粘连紧密不易分开。笔者团队自制可调节式内膜剥离器用于取出亚急性下肢动脉栓塞病人的陈旧性机化血栓。现报告如下。 相似文献
94.
95.
96.
目的:比较各种影像检查在胆道梗阻患者的诊断上的优劣。方法:分析89例年龄在12-75岁的胆道梗阻患者的CT、B超,胆道造影资料。结果:对胆管癌,胰头癌,炎性狭窄,肝癌,壶腹癌的诊断,胆道造影与病理的符合率较高,肿大淋巴结的诊断,CT与B超较胆道造影与病理的符合率高,对于梗阻部位,胆道造影,CT与手术的符合率较B超与手术符合率高。结论:胆道造影与CT对梗阻部位及原因的诊断准确率较高。B超的临床实用性较高。 相似文献
97.
Abhinit Kumar Sudhir Bahadur Suberendra Kumar Sima Mukhopadhyay Meera Mathur 《Indian journal of otolaryngology and head and neck surgery》2000,52(3):230-234
Twelve patients undergoing surgery between May 1995 and March 1999 for malignant tumours of the paranasal sinuses abutting
or invading the orbital walls were studied for the need to remove orbital contents. Alt patients were evaluated clinically,
radiologically (CT Scan) and per-operatively to delineate the extent of orbital invasion. Combined regimen (Surgery + Radiotherapy)
were used in all patients. A biopsy from periorbita was taken when eye was spared. It was found that per-operative evaluation
of the orbit is equally specific in comparision to clinical and CT Scan combined and eye may be preserved in selected patients
with involvement of orbital periosteum provided there is no frank soft tissue mass in the orbit. 相似文献
98.
Bernd Niederhagen N. Leipner S. Bergé J.-J. von Lindern T. Appel 《Mund-, Kiefer- und Gesichtschirurgie》2000,4(4):217-221
Problem: There is a lack of clear criteria for the use of MR and CT in the diagnosis of head and neck cancer – some of it
is even contradictory. The results of this study should lead to the establishment of more clear criteria. Patients: 165 patients
suffering from head and neck tumors were subjected to a total of 463 CT and 197 MRI examinations. Results: The CT and MRI
staging corresponded in 67% and 60% of the oropharynx tumors, respectively, with the clinical findings. In the case of oral
cavity tumors, the clinical TNM stages were identical with CT and MRI results in 50% and 43% of cases, respectively. In the
case of lymphatic node staging, the frequency of error was slightly higher using MRI, at 27%, compared with the CT rate of
22%. In the evaluation of cervical lymphatic nodes, CT proved to be more sensitive attaining 78% compared to the MRI rate
of 69%. Conclusion: The results provide clear indications as to the MRI and CT examinations. Primary preoperative screening
and post-therapeutic aftercare should be assessed using CT, as should lymphatic node diagnosis in the neck area. In the case
of special problems such as, for example, the relevant bone and periostium infiltration, MR should be considered as a supplementary
examination at a second stage.
相似文献
99.
颅底富血供肿瘤术前超选择性颈外动脉插管栓塞9例报告 总被引:3,自引:0,他引:3
目的:探讨超选择性颈外动脉插管栓塞术在颅底富血供肿瘤手术治疗中的作用。方法:对9例颅底富血供肿瘤患者术前先作双侧颈内、颈外及椎动脉造影后再行栓塞治疗。结果:9例栓塞后,肿瘤供血网显影消失,术中出血量明显减少,术后病理检查,镜下均见瘤体微血管及血窦内充满大量明胶海绵。结论:超选择性颈外动脉插管造影,在明确肿瘤血供类型后辅以术前栓塞治疗,既可缩小瘤体又能减少术中出血,是肿瘤围手术期处理的重要手段之一。 相似文献
100.
席道友 《第三军医大学学报》2000,22(2):128
肺部CT扫描小病灶易遗漏 ,扫描前对定位图像观察细致 ,定位准确 ,则可达到检出病灶的目的 ,现报告如下。1临床资料1997年8月至1998年1月10例肺部0.5~0.8cm小病灶 ,男7例 ,女3例 ,年龄17~83岁 ,平均年龄57岁。病人仰卧于检查床上 ,双手抱紧头部 ,臀部垫高15°~25° ,定位线对准锁骨连线中心 ,先扫描全肺像 ,再根据病变情况 ,设定扫描程序。我科采用美国GEsystec3000型全身CT机 ,取XY轴线 ,从小病灶上缘 ,以3mm层厚 ,3mm层距 ,扫到病灶下缘为止。其他肺野 ,可用10mm层厚 ,1… 相似文献