全文获取类型
收费全文 | 32543篇 |
免费 | 2383篇 |
国内免费 | 2127篇 |
专业分类
耳鼻咽喉 | 152篇 |
儿科学 | 357篇 |
妇产科学 | 160篇 |
基础医学 | 4028篇 |
口腔科学 | 458篇 |
临床医学 | 3655篇 |
内科学 | 1574篇 |
皮肤病学 | 68篇 |
神经病学 | 5993篇 |
特种医学 | 1277篇 |
外国民族医学 | 4篇 |
外科学 | 9574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 | 493篇 |
肿瘤学 | 979篇 |
出版年
2024年 | 129篇 |
2023年 | 618篇 |
2022年 | 1047篇 |
2021年 | 1354篇 |
2020年 | 1238篇 |
2019年 | 1010篇 |
2018年 | 1071篇 |
2017年 | 1160篇 |
2016年 | 1117篇 |
2015年 | 1159篇 |
2014年 | 1984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
71.
Summary It has been widely observed that the outcome after repeat lumbar surgery is rarely comparable to that of primary surgery. In particular, the results of repeat surgery for lumbar spinal stenosis (LSS) have not been favourable. We used a matched-pair format in an attempt to decrease the confounding factors so as to determine as exactly as possible the effect of prior back surgery on the LSS patients surgical outcome. The matching criteria were sex, age, myelographic findings, major symptom, and duration of symptoms. From one group of 251 patients without prior back surgery (SO patients) and another of fifty-three patients with one preceding back operation (RS patients), forty-one similar matched patients pairs (one SO and one RS-patient) were formed.There were 8 female and 33 male pairs. The mean age of the SO patients was 51.6 and of the RS patient 51.4 years, and the mean follow-up time was 4.6 and 4.4 years. The assessment of outcome was based on a subjective disability questionnaire. The SO patients fared significantly better than the RS patients (32.1 versus 41.3, P = 0.026). A short time interval between operations in the RS patients had a worsening effect on outcome, but this trend was not significant.We concluded that one preceding back operation had a worsening effect on the outcome of patients operated on for LSS. As a whole, the results of RS patients were unfavourable. The proper time for achieving good surgical results in LSS patients is the initial operation. 相似文献
72.
73.
Two-level posterior lumbar interbody fusion for degenerative disc disease: improved clinical outcome with restoration of lumbar lordosis 总被引:2,自引:0,他引:2
Akira Hioki MD Kei Miyamoto MD PhD Hirotaka Kodama MD PhD Hideo Hosoe MD PhD Hirofumi Nishimoto MD Hirofumi Sakaeda MD PhD Katsuji Shimizu MD DMSc 《The spine journal》2005,5(6):600-607
BACKGROUND CONTEXT: Although posterior lumbar interbody fusion (PLIF) for degenerative lumbar diseases is routine, there are few reports on double-level PLIF. PURPOSE: To evaluate the clinical outcomes of double-level PLIF. STUDY DESIGN/SETTING: A retrospective study of operated cases in Gifu, Japan. PATIENT SAMPLE: Nineteen patients (8 men and 11 women, 59.5+/-10.2 years) who underwent double-level PLIF between 1996 and 2001. OUTCOME MEASURES: Operation time, blood loss, complications, the Japanese Orthopaedic Association (JOA) score for back pain and lumbar sagittal alignment were evaluated. METHODS: Patients were examined retrospectively at follow-ups of 3.6+/-1.7 years. Primary diseases were spondylolisthesis, spinal canal stenosis, degenerative scoliosis and herniated intervertebral disc. Fusion areas were L3 to L5 in 15 cases and L4 to S1 in 4 cases. RESULTS: The mean JOA score increased from an initial score of 12.9+/-3.5 to 21.3+/-4.9 at the final follow-up. There was a positive correlation (R=0.718, p<.001) between the increase in lordotic angle and the increase in the JOA score. Several parameters suggested that the surgical invasiveness was not minimal. CONCLUSION: Double-level PLIF provided satisfactory results and preserved lumbar spine lordosis. 相似文献
74.
75.
鞘内注射吗啡对切口疼痛大鼠脊髓背角蛋白激酶Cγ免疫反应的影响 总被引:1,自引:0,他引:1
目的 研究鞘内注射吗啡对切口疼痛大鼠脊髓背角蛋白激酶Cγ(PKCγ)免疫反应的影响。方法 SD雄性大鼠24只,随机分为4组(每组6只):假手术组(Ⅰ组)、对照组(Ⅱ组)术前30 min鞘内注射人工脑脊液20μl,术后吗啡治疗组(Ⅲ组)、术前吗啡治疗组(Ⅳ组)分别于术后和术前30min鞘内注射吗啡5μg(10 μl)。所有大鼠均按Brennan法制成切口疼痛模型,用免疫组织化学方法观察脊髓背角PKCγ的表达。结果 Ⅱ组术侧脊髓背角PKCγ-IR表达高于非术侧及Ⅰ组(P<0.01)。与Ⅱ组比较,Ⅲ组、Ⅳ组脊髓背角PKCγ-IR表达降低(P<0.05或0.01),而Ⅲ组、Ⅳ组比较差异无显著性。结论 在大鼠切口疼痛模型中,鞘内注射吗啡的镇痛作用可能与抑制脊髓背角的PKCγ-IR免疫反应有关。 相似文献
76.
77.
Cervifix在陈旧性寰枢椎脱位并高位颈髓压迫症中的应用 总被引:9,自引:3,他引:6
目的:探讨Cervifix内固定系统治疗陈旧性寰枢椎脱位并脊髓不全损伤的价值。方法:36例陈旧性寰枢椎脱位并脊髓不全损伤行后路融合、Cervifix内固定。男23例、女13例,年龄15~62岁,平均38.3岁。陈旧性外伤21例,先天性畸形9例,类风湿性关节炎伴寰椎前脱位6例。结果:随访8~42个月,平均19个月。术后脊髓功能按JOA17分法评定,改善率为71.4%。全部患者均获骨性融合,内置物无松动、断裂及脊髓损伤加重等并发症。结论:Cervifix内固定可提供坚强有效的节段性固定,提高融合率。同时,可预防单纯减压融合术后早期失稳导致的高位脊髓损伤加重。 相似文献
78.
Background: Tibialis posterior is a frequent cause of an acquired flatfoot deformity and the prevalence is not known. If tibialis posterior dysfunction was found to occur frequently, a greater awareness may result leading to earlier patient diagnosis, referral and treatment.Objectives: To validate a screening questionnaire for tibialis posterior dysfunction, and to investigate the prevalence of tibialis posterior dysfunction in a high-risk patient population.Methods: The screening questionnaire was given prospectively to 65 patients (44 females, 21 males; mean age 79.6 years) attending an unrelated care of the elderly appointment. A foot and ankle surgery fellow separately examined all feet for tibialis posterior dysfunction.Results: The survey was 100% sensitive and 98.3 % specific at detecting tibialis posterior dysfunction. Six of the 65 patients (5 females, 1 male) had tibialis posterior dysfunction, and two had bilateral involvement. All six of the patients had longstanding symptoms, all had consulted their doctor and three had seen an orthopaedic surgeon; only one of the six patients had been correctly diagnosed.Conclusions: This study suggests that tibialis posterior dysfunction occurs frequently, but is seldom diagnosed in elderly women. Further epidemiologic studies are needed to determine the true prevalence. 相似文献
79.
中下段颈椎的应力松弛特性及前、后路手术对其的影响 总被引:3,自引:1,他引:2
目的 研究中下段颈椎的应力松弛特性,并评估椎间盘切除植骨术与椎板切开术对其影响。方法 6例新鲜尸体完整颈椎及手术后颈椎,在模拟生理状态下进行屈曲及伸展位的应力松弛实验。结果 在恒应变条件下,绘制术前及不同术式后的中下段颈椎的应力松弛函数及曲线;术后的中下段颈椎的应力和初始化应力比值G(t)比术前明显增大,前路椎间盘切除植骨术后的G(t)值比椎板切开术大,两者均有统计学意义。结论 在恒应变条件下,颈椎具有快速应力松弛敏感性,屈曲位比伸展位大。椎板成形术及颈椎前路椎间盘切除植骨术都使颈椎的应力松弛能力减弱,前路椎间盘切除植骨术的影响更大。 相似文献
80.
The blood–brain barrier (BBB) is an immense neurovascular interface. In neurodegenerative, ischemic, and traumatic disorders of the central nervous system (CNS), the BBB may hinder the delivery of many therapeutic peptides and proteins to the brain and spinal cord. Fortunately, the mistaken dogma that peptides and proteins do not cross the BBB has been corrected during the past two decades by the accumulating evidence that peptides and proteins in the periphery exert potent effects in the CNS. Not only can peptides and proteins serve as carriers for selective therapeutic agents, but they themselves may directly cross the BBB after delivery into the bloodstream. Their passage may be mediated by simple diffusion or specific transport, both of which can be affected by interactions in the blood compartment (outside the BBB) and within the endothelial cells (at the BBB level). Although the majority of current delivery strategies focuses on modification of the molecule to be delivered, understanding the mechanisms of transport will eventually facilitate regulation of the BBB directly. We review the different aspects of interactions and discuss recent advances in the cell biology of peptide/protein transport across the BBB. Better understanding of the nature and regulation of the transport systems at the BBB will provide a new direction to enhance the interactions of peripheral peptides and proteins with the CNS. 相似文献