全文获取类型
收费全文 | 32699篇 |
免费 | 2232篇 |
国内免费 | 2142篇 |
专业分类
耳鼻咽喉 | 152篇 |
儿科学 | 358篇 |
妇产科学 | 160篇 |
基础医学 | 4037篇 |
口腔科学 | 458篇 |
临床医学 | 3660篇 |
内科学 | 1574篇 |
皮肤病学 | 68篇 |
神经病学 | 5996篇 |
特种医学 | 1277篇 |
外国民族医学 | 4篇 |
外科学 | 9575篇 |
综合类 | 4729篇 |
现状与发展 | 3篇 |
预防医学 | 644篇 |
眼科学 | 1361篇 |
药学 | 1527篇 |
17篇 | |
中国医学 | 494篇 |
肿瘤学 | 979篇 |
出版年
2024年 | 133篇 |
2023年 | 622篇 |
2022年 | 1047篇 |
2021年 | 1365篇 |
2020年 | 1237篇 |
2019年 | 1010篇 |
2018年 | 1071篇 |
2017年 | 1160篇 |
2016年 | 1117篇 |
2015年 | 1159篇 |
2014年 | 1986篇 |
2013年 | 2333篇 |
2012年 | 1693篇 |
2011年 | 1840篇 |
2010年 | 1662篇 |
2009年 | 1547篇 |
2008年 | 1499篇 |
2007年 | 1599篇 |
2006年 | 1477篇 |
2005年 | 1301篇 |
2004年 | 1161篇 |
2003年 | 1084篇 |
2002年 | 875篇 |
2001年 | 723篇 |
2000年 | 575篇 |
1999年 | 553篇 |
1998年 | 532篇 |
1997年 | 461篇 |
1996年 | 378篇 |
1995年 | 332篇 |
1994年 | 319篇 |
1993年 | 262篇 |
1992年 | 250篇 |
1991年 | 217篇 |
1990年 | 195篇 |
1989年 | 230篇 |
1988年 | 163篇 |
1987年 | 151篇 |
1986年 | 192篇 |
1985年 | 317篇 |
1984年 | 285篇 |
1983年 | 230篇 |
1982年 | 195篇 |
1981年 | 178篇 |
1980年 | 142篇 |
1979年 | 54篇 |
1978年 | 70篇 |
1977年 | 36篇 |
1976年 | 23篇 |
1975年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
目的观察咪唑安定加入布比卡因对蛛网膜下腔麻醉维持时间和麻醉效果的影响。方法40例ASAⅠ级子宫切除病人随机分为咪唑安定组(试验组,11=20)和对照组(n=20)。咪唑安定组蛛网膜下腔注入0.5%重比重布比卡因2.5ml加咪唑安定1mg(0.2m1),对照组注入0.5%重比重布比卡因2.5ml加生理盐水0.2ml。观察运动神经阻滞(改良Bromage)、感觉神经阻滞(针刺法)、镇痛时间(VAS)、术者和患者对麻醉的满意率。结果咪唑安定组感觉和运动神经阻滞时间显著延长(P〈0.01),术者和患者对麻醉的满意率提高(P〈0.05)。咪唑安定组有效镇痛时间也显著延长(P〈0.001)。两组血流动力学、不良反应情况差别无显著性。结论咪哗安定加入布比卡因能显著延长麻醉作用时间,麻醉效应增强,而不良反应未见增加。 相似文献
92.
93.
Michael J. Gardner MD Sreevathsa Boraiah MD Keith D. Hentel MD David L. Helfet MD Dean G. Lorich MD 《The Journal of foot and ankle surgery》2007,46(4):256-260
Various patterns of ankle fractures that are not accounted for by common classification systems have been the subject of case reports. The first difficulty with these variant patterns is recognizing all associated pathology, followed by the successful application of stable fixation. The purpose of this study was to describe the common morphologic features and ligamentous injuries of a unique variant fracture pattern, as well as the surgical treatment technique and the short-term functional and radiographic outcomes. Of 121 consecutive unstable ankle fractures over a 2-year period, 7 patients were found to have a similar constellation of injuries around the ankle. A vertical shear fracture of the posteromedial tibial rim was the main feature. Six of the 7 also had a fracture of the posterior malleolus. On magnetic resonance imaging, the deltoid and posterior tibiofibular ligaments were intact in all cases. Fractures were treated with open anatomic reduction of the posteromedial and posterior fragments with antiglide plate fixation. All fractures healed at 2 months without loss of reduction, fixation failure, or surgical complications. The average American Academy of Orthopaedic Surgeons lower extremity score was 79 at an average of 8 months' follow-up. The common radiographic and morphologic features associated with this posteromedial fracture indicate that it likely occurs through a common mechanism that involves hyperplantarflexion. The characteristics of this fracture pattern have not been fully described previously, but this ankle fracture variant may occur in up to 6% of cases. Unstable ankle fractures should be evaluated carefully for evidence of posteromedial involvement so appropriate treatment may proceed. 相似文献
94.
Linda J. Richards Trevor J. Kilpatrick Renee Dutton Seong-Seng Tan David P. Gearing Perry F. Bartlett Mark Murphy 《The European journal of neuroscience》1996,8(2):291-299
Previously we have shown that leukaemia inhibitory factor (LIF) potentiates the development of murine spinal cord neurons in vitro , suggesting that it, or related factors, may play an important regulatory role in neuronal development. We have further investigated this role and show here that the generation of neurons in cultures of embryonic day 10 spinal cord cells is inhibited by antibodies to the β subunit of the LIF receptor. Since there are more undifferentiated precursors in antibody-treated cultures than in control and LIF-treated cultures, it is concluded that the primary action of LIF, or related molecules, is to promote neuronal differentiation, not precursor survival. In addition, the failure of LIF to support neuronal survival in the period immediately following differentiation suggests that the increased numbers of neurons generated with LIF are not attributable to its neurotrophic action. By selecting neuronal precursors on the basis of their inability to express class I major histocompatibility complex molecules, it was shown that LIF acted directly upon these cells and not via an intermediary cell. LIF also appears to be involved in regulating the differentiation of astrocytes, since it increases the number of glial fibrillary protein (GFAP)-positive cells present in the cultures and since the spontaneous production of GFAP-positive cells is blocked by antibodies to the LIF β receptor. These findings suggest that LIF or related factors promote the differentiation of neural precursors in the spinal cord, but that they are not involved in preferentially promoting precursors down a specific differentiation pathway. 相似文献
95.
96.
Alan J. McComas 《Muscle & nerve》1995,18(4):369-379
97.
98.
核医学影像设备的发展与临床应用 总被引:3,自引:3,他引:0
γ相机和SPECT只能进行常规单光子显像,PET和双探头SPECT符合显像系统既能进行单光子显像,又能进行正电子符合显像,PET/CT系统的出现不仅提供高质量的衰减校正图像,保证了正电子显像校正数据的可靠性,而且能进行同机图像融合,提高了影像定位诊断的准确性。本文简要介绍了核医学影像设备发展历程,PET和PET/CT的原理以及在临床的应用。 相似文献
99.
M. Pitkänen M.D. P. Rosenberg M. Silvanto M. Tuominen 《Acta anaesthesiologica Scandinavica》1992,36(6):526-529
Forty elderly patients, scheduled for orthopaedic surgery of the hip or knee were studied. Twenty patients received a single-dose spinal anaesthesia with 3 ml of plain 0.5% bupivacaine (SDSA group). Twenty patients received continuous spinal anaesthesia using a 32- or 22-gauge catheter. A bolus of 1.0 ml of plain 0.5% bupivacaine was given to ten patients and 0.5 ml to another ten, continued by an infusion at a rate of 2 ml/h. The spread of analgesia and haemodynamic changes (central venous pressure, arterial pressures, need for sympathomimetic medication) were registered. The mean dose of bupivacaine was 2.9 ml (range 1.5-5 ml) in the CSA group (3.0 ml in the SDSA group). Eight patients in the CSA group needed medication for pain during surgery compared to five patients in the SDSA group (n.s.). The median level of pinprick analgesia at 60 min was T11 in the CSA and T6.5 in the SDSA group (P less than 0.01). The mean maximum decreases in CVP and MAP were quite similar in the CSA and SDSA group (2.1 vs 2.8 mmHg (0.3 vs 0.4 kPa) and 17 vs 21 mmHg (2.3 vs 2.8 kPa), respectively) (n.s.). Six patients in the SDSA group and four patients in the CSA group needed sympathomimetic medication. It is concluded that titration of bupivacaine for spinal anaesthesia caused only minor haemodynamic changes which were similar to those after single-dose spinal bupivacaine. 相似文献
100.
Magnetic resonance imaging (MRI) has greatly facilitated morphologic evaluation of spinal cord lesions. Eleven cases representative of inflammatory, demyelinating, neoplastic and vascular diseases, are presented which illustrate and summarize important abnormal features in spinal cord imaging, particularly MR findings. Recently, specialised techniques such as MR angiography, fat-inhibiting methods, dynamic MRI and functional imaging have been developed. These methods have facilitated not only lesion diagnosis but also qualitative assessment, and are being used to analyze pathophysiology. Comprehensive diagnoses based on such modalities may be important in determining indications for surgery or defining the extent of surgery or the intensity of other treatments. 相似文献