全文获取类型
收费全文 | 103184篇 |
免费 | 31374篇 |
国内免费 | 1105篇 |
专业分类
耳鼻咽喉 | 2566篇 |
儿科学 | 2803篇 |
妇产科学 | 2474篇 |
基础医学 | 2751篇 |
口腔科学 | 5450篇 |
临床医学 | 27586篇 |
内科学 | 26260篇 |
皮肤病学 | 3482篇 |
神经病学 | 12644篇 |
特种医学 | 3765篇 |
外科学 | 18848篇 |
综合类 | 220篇 |
现状与发展 | 40篇 |
一般理论 | 9篇 |
预防医学 | 14048篇 |
眼科学 | 2312篇 |
药学 | 1279篇 |
中国医学 | 21篇 |
肿瘤学 | 9105篇 |
出版年
2024年 | 774篇 |
2023年 | 5227篇 |
2022年 | 1157篇 |
2021年 | 2852篇 |
2020年 | 5519篇 |
2019年 | 2063篇 |
2018年 | 7106篇 |
2017年 | 7585篇 |
2016年 | 8157篇 |
2015年 | 8294篇 |
2014年 | 10871篇 |
2013年 | 12673篇 |
2012年 | 3906篇 |
2011年 | 3748篇 |
2010年 | 7094篇 |
2009年 | 9432篇 |
2008年 | 3699篇 |
2007年 | 2603篇 |
2006年 | 3814篇 |
2005年 | 2299篇 |
2004年 | 1679篇 |
2003年 | 1356篇 |
2002年 | 1261篇 |
2001年 | 1967篇 |
2000年 | 1250篇 |
1999年 | 1834篇 |
1998年 | 2237篇 |
1997年 | 2074篇 |
1996年 | 2090篇 |
1995年 | 1846篇 |
1994年 | 1198篇 |
1993年 | 1012篇 |
1992年 | 823篇 |
1991年 | 714篇 |
1990年 | 581篇 |
1989年 | 594篇 |
1988年 | 561篇 |
1987年 | 437篇 |
1986年 | 400篇 |
1985年 | 350篇 |
1984年 | 318篇 |
1983年 | 346篇 |
1982年 | 282篇 |
1981年 | 247篇 |
1980年 | 172篇 |
1978年 | 161篇 |
1977年 | 155篇 |
1976年 | 107篇 |
1975年 | 93篇 |
1974年 | 97篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Christoph Scherfler MD Johannes Schwarz MD PhD Angelo Antonini MD PhD Donald Grosset MD Francesc Valldeoriola MD PhD Kenneth Marek MD Wolfgang Oertel MD Eduardo Tolosa MD PhD Andrew J. Lees MD Werner Poewe MD 《Movement disorders》2007,22(9):1229-1238
The diagnosis of idiopathic Parkinson's disease (PD) can be achieved with high degrees of accuracy in cases with full expression of classical clinical features. However, diagnostic uncertainty remains in early disease with subtle or ambiguous signs. Functional imaging has been suggested to increase the diagnostic yield in parkinsonian syndromes with uncertain clinical classification. Loss of striatal dopamine nerve terminal function, a hallmark of neurodegenerative Parkinsonism, is strongly related to decreases of dopamine transporter (DAT) density, which can be measured by single photon emission computed tomography (SPECT). The use of DAT‐SPECT facilitates the differential diagnosis in patients with isolated tremor symptoms not fulfilling PD or essential tremor criteria, drug‐induced, psychogenic and vascular Parkinsonism as well as dementia when associated with Parkinsonism. This review addresses the value of DAT‐SPECT in early differential diagnosis, and its potential as a screening tool for subjects at risk of developing PD as well as issues around the assessment of disease progression. © 2007 Movement Disorder Society 相似文献
992.
In Vitro Wear of Nano-Composite Denture Teeth 总被引:2,自引:0,他引:2
PURPOSE: Few laboratory tests have been able to substantiate and quantify the wear resistances of polymeric denture teeth. This study evaluated the relative wear resistance of several types of denture teeth using an in vitro wear testing device. MATERIAL AND METHODS: Four different types of denture teeth [nano-filled (Veracia) and micro-filled composites (SR-Orthosit, Endura, Duradent, Surpass), cross-linked acrylic (SR-Postaris, Genios-P, Creapearl, Vitapan Physiodens, Premium 8, Integral), and a conventional acrylic (Biotone)] were used. The flattened buccal surface of each denture tooth was subjected to the evaluation of Knoop hardness (n=5) and localized wear for 100,000 cycles (n=10). Wear values were determined in micrometers using a profilometer. The data for the hardness, wear depth, and worn surface areas were individually analyzed by one-way ANOVA. RESULTS: Knoop hardness values (KHN) ranged from 28.2 to 29.8 for micro-filled composite, 18.9 to 21.6 for cross-linked acrylic, 22.7 for nano-composite, and 18.6 for conventional acrylic teeth. All micro-filled composite teeth were significantly harder than other teeth (p <0.0001). The wear depth values were 90.5 microm for the nano-composite, 69.8 to 93.0 microm for the micro-filled composite, 80.8 to 104.0 microm for the cross-linked acrylic, and 162.5 microm for conventional acrylic teeth. The worn surface areas were 5.1 mm2 for the nano-composite, 2.6 to 3.6 mm2 for the micro-filled composite, 4.4 to 5.7 mm2 for the cross-linked acrylic, and 10.1 mm2 for conventional acrylic teeth. The wear values of the acrylic control were significantly different from all other denture teeth (p <0.001). CONCLUSION: The nano-composite tooth was harder and more wear resistant than the acrylic teeth but not significantly different from most of the cross-linked and micro-filled composite teeth tested. 相似文献
993.
Certain drugs or chemicals may be added to local anesthetic solutions to enhance the tissue spread of the local anesthetic. Perhaps the best known is glucose (dextrose) added to spinal anesthesia solution to make it hyperbaric and to allow the local anesthetic to spread in the cerebrospinal fluid by gravity, as needed. Hyaluronidase addition has been abandoned in almost all other regional anesthetic blocks except ophthalmologic blocks. Hylauronidase is expensive and it is not devoid of side-effects and, therefore, as low concentrations as possible are recommended. Even as low concentration as 3.75 IU/mL of hyaluronidase is able to enhance the spread of the concentrated local anesthetic solution, causing analgesia and akinesia without damage to the eye muscles. Hyaluronidase addition to local anesthetic solutions is used to some extent also in dermatological surgery. The spread of local anesthetics for topical skin analgesia and anesthesia is promoted by influencing the penetrating property physically (eutectic mixture), electrically (iontophoresis), and encapsulating in liposomes. The penetration (spread) of the local anesthetic through the skin is significantly faster with iontophoresis and liposomes in comparison with the eutectic mixture of local anesthetics. 相似文献
994.
995.
996.
997.
Amy Y. Chen MD MPH Nicole Schrag MSPH Yongping Hao PhD W. Dana Flanders MD DSc James Kepner PhD Andrew Stewart MS Elizabeth Ward PhD 《Otolaryngology--head and neck surgery》2006,135(6):831-837
OBJECTIVE: In 1991, a randomized study was published and demonstrated that use of nonsurgical therapy (chemoradiation) provided similar survival to total laryngectomy (the gold standard) for patients with advanced-stage laryngeal cancer. The purpose of this study was to assess how treatment of advanced laryngeal cancer was influenced by such developments in non-surgical therapy. STUDY DESIGN: Patterns of care study using National Cancer Database (1985-2001). RESULTS: The percentage of advanced-stage patients treated with chemoradiation increased from 8.3% to 20.8% while the proportion treated with radiation alone decreased from 38.9% to 23.0%. Use of chemoradiation increased at a significantly faster rate after the 1991 publication at both community cancer centers and teaching research facilities. The use of total laryngectomy decreased slightly during this period. CONCLUSIONS: The use of chemoradiation increased after the 1991 publication. It was impossible to determine from the NCDB whether additional patients who could benefit from chemo-RT were not offered or did not complete this treatment option. We recommend that treatment recommendations discussed at tumor boards be recorded in cancer registries. 相似文献
998.
999.
INTRODUCTION: Reconstructive septorhinoplasty in complex nasal deformities often requires harvesting a large amount of tissue for grafting. Autogenous septal cartilage has generally been considered the gold standard grafting material. The aim of this paper was to report our experience with the use of costal cartilage grafts in cases with significant structural deformities and insufficient septal cartilage. DESIGN: Retrospective chart review. PATIENTS: Between 1998 and 2006, 37 patients underwent septorhinoplasty using costal cartilage as the primary source for grafting. Twenty-two men and 14 women with a median age of 42 were enrolled in the study. Patient demographics, indications for surgery, and immediate and late complications were reviewed. The follow-up range was 3 to 72 months. CONCLUSIONS: Autogenous costal cartilage graft is a viable option in reconstructive septorhinoplasty. We advocate the use of this graft in septorhinoplasty cases requiring a large volume of tissue and insufficient septal cartilage. 相似文献
1000.