全文获取类型
收费全文 | 2674篇 |
免费 | 122篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 180篇 |
妇产科学 | 167篇 |
基础医学 | 178篇 |
口腔科学 | 162篇 |
临床医学 | 168篇 |
内科学 | 460篇 |
皮肤病学 | 58篇 |
神经病学 | 252篇 |
特种医学 | 88篇 |
外科学 | 727篇 |
综合类 | 21篇 |
一般理论 | 1篇 |
预防医学 | 44篇 |
眼科学 | 64篇 |
药学 | 79篇 |
肿瘤学 | 89篇 |
出版年
2024年 | 3篇 |
2023年 | 32篇 |
2022年 | 63篇 |
2021年 | 108篇 |
2020年 | 78篇 |
2019年 | 86篇 |
2018年 | 103篇 |
2017年 | 93篇 |
2016年 | 125篇 |
2015年 | 143篇 |
2014年 | 135篇 |
2013年 | 162篇 |
2012年 | 219篇 |
2011年 | 217篇 |
2010年 | 118篇 |
2009年 | 105篇 |
2008年 | 168篇 |
2007年 | 183篇 |
2006年 | 159篇 |
2005年 | 126篇 |
2004年 | 98篇 |
2003年 | 65篇 |
2002年 | 81篇 |
2001年 | 25篇 |
2000年 | 29篇 |
1999年 | 19篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 14篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
排序方式: 共有2818条查询结果,搜索用时 0 毫秒
91.
González-Duarte Alejandra Berk John L. Quan Dianna Mauermann Michelle L. Schmidt Hartmut H. Polydefkis Michael Waddington-Cruz Márcia Ueda Mitsuharu Conceição Isabel M. Kristen Arnt V. Coelho Teresa Cauquil Cécile A. Tard Céline Merkel Madeline Aldinc Emre Chen Jihong Sweetser Marianne T. Wang Jing Jing Adams David 《Journal of neurology》2020,267(3):713-714
Journal of Neurology - The original version of this article unfortunately contained a mistake. 相似文献
92.
93.
Self-healing is the capability of materials to repair themselves after the damage has occurred, usually through the interaction between molecules or chains. Physical and chemical processes are applied for the preparation of self-healing systems. There are different approaches for these systems, such as heterogeneous systems, shape memory effects, hydrogen bonding or covalent–bond interaction, diffusion, and flow dynamics. Self-healing mechanisms can occur in particular through heat and light exposure or through reconnection without a direct effect. The applications of these systems display an increasing trend in both the R&D and industry sectors. Moreover, self-healing systems and their energy storage applications are currently gaining great importance. This review aims to provide general information on recent developments in self-healing materials and their battery applications given the critical importance of self-healing systems for lithium-ion batteries (LIBs). In the first part of the review, an introduction about self-healing mechanisms and design strategies for self-healing materials is given. Then, selected important healing materials in the literature for the anodes of LIBs are mentioned in the second part. The results and future perspectives are stated in the conclusion section. 相似文献
94.
Kurtoglu M Yanar H Taviloglu K Sivrikoz E Plevin R Aksoy M 《The American surgeon》2007,73(10):1039-1043
Management of lower extremity venous trauma using repair or ligation has been an area of controversy during the past decades. However, in unstable patients or if primary repair is technically impossible as a result of extensive disruption of the vein, ligation is recommended. This study investigated the effects of venous ligation on major veins in the lower extremities when primary repair is impossible as a result of extensive laceration of the vein. Between January 2001 and April 2004, 63 patients with Grade III and IV venous injuries were observed prospectively. Compression ultrasonography was performed postoperatively on the fifth day, once before discharge, and at the 3-month visit to assess deep vein thrombosis (DVT) and the patency of arterial repair. If DVT was present, the patient was given an oral anticoagulant (warfarin Na) for 3 months (international normalized ratio, 2.0-3.0), and Class II compression stockings (Sigvaris-212, Ganzoni, Switzerland) were used for 1 year. Follow-up visits occurred at 1, 3, 6, and 12 months and at 6-month intervals thereafter. Combined arterial and venous injuries were present in 50 (79.4%) patients and pure venous injuries were present in 13 (20.6%) patients. DVT developed in 49 patients (77.7%; postoperative n = 37 [58.7%], late n = 12 [19%]). Three arterial restenoses (4.7%) and one pseudoaneurysm (1.6%) of the superficial femoral artery developed. Five early (prophylactic) and two late (compartment syndrome) fasciotomies were performed. Postoperative edema was seen in 56 (88.8%) patients and wound infection was seen in 19 patients (30.1%; n=18 superficial, n=1 deep). Two amputations (3.2%) were performed. One patient (1.7%) died as a result of irreversible shock. After a median of 18 months, 25 patients were classified with Clinical Etiology, Anatomy, Pathology classification: 10 legs C-0, seven legs C-2, and eight legs C-3. No severe postthrombophlebitic syndrome was observed. Early leg swelling after venous ligation was the most common morbidity. We observed no significant sequelae of chronic venous insufficiency, and venous ligation had no detrimental effect on associated arterial repair. In cases of DVT, anticoagulation with low-molecular-weight heparin and oral anticoagulants should begin immediately and continue for 3 months along with compression stocking support for 1 year. 相似文献
95.
96.
Eda E. AslantasHatice Dogan Buzoglu DDS PhD Emre AltundasarAhmet Serper DDS PhD 《Journal of endodontics》2014
Introduction
This study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents.Methods
Forty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05.Results
EDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05).Conclusions
The addition of surface modifiers to the irrigants did not affect the microhardness of the samples. 相似文献97.
Dikbas I Tanalp J Ozel E Koksal T Ersoy M 《The journal of contemporary dental practice》2007,8(7):62-69
AIM: The purpose of this study was to evaluate the fracture resistance of endodontically treated maxillary central incisors restored with quartz fiber posts, composite cores, and crowns when different types of ferrule designs were incorporated. METHODS AND MATERIALS: Sixty maxillary incisors were divided into six groups: Group 1 (control): teeth with root canal treatments having a full crown prosthesis; Group 2: teeth with a 2 mm circumferential ferrule; Group 3: teeth with a 2 mm ferrule only in the vestibular region; Group 4: teeth with a 2 mm ferrule only in the palatal region; Group 5: teeth with a 2 mm ferrule in the vestibular and palatal region, having cavities in both proximal areas; and Group 6: teeth with no ferrule. The teeth in the experimental groups were restored with quartz fiber posts-composite cores and full metallic crowns. All experimental teeth were subjected to an increasing compressive force with a crosshead speed of 1 mm/min, until fracture occurred. RESULTS: The median fracture values of groups were as follows: Group 1: 574.4 N, Group 2: 472.4 N, Group 3: 474.3 N, Group 4: 480.7 N, Group 5: 463.1 N, and Group 6: 297.9 N. A statistically significant difference was found between Group 1 and Group 6 (p< 0.01). CONCLUSION: It was concluded different ferrule designs did not have any influence on the fracture resistance of teeth with fiber posts. The results of this study indicate fiber posts can safely be used for their reinforcing properties. Furthermore, there is no significant change in the resistance of teeth with fiber posts regardless of which ferrule design is incorporated. The property of these types of posts is an additional advantage in clinical practice. 相似文献
98.
Fontenelle LF Harrison BJ Pujol J Davey CG Fornito A Bora E Pantelis C Yücel M 《Journal of psychiatry & neuroscience : JPN》2012,37(4):231-240
Background
Obsessive–compulsive disorder (OCD) is associated with a range of emotional abnormalities linked to its defining symptoms, comorbid illnesses and cognitive deficits. The aim of this preliminary study was to examine functional changes in the brain that are associated with experimentally induced sad mood in patients with OCD compared with healthy controls in a frontolimbic circuit relevant to both OCD and mood regulation.Methods
Participants underwent a validated sad mood induction procedure during functional magnetic resonance imaging. Analyses focused on mapping changes in the functional connectivity of the subgenual anterior cingulate cortex (ACC) within and between the 2 groups in response to successfully induced sadness.Results
We enrolled 11 patients with OCD and 10 age-, sex- and IQ-matched controls in our study. Unlike controls, patients with OCD did not demonstrate predicted increases in functional connectivity between the subgenual ACC and other frontal regions during mood induction. Instead, patients demonstrated heightened connectivity between the subgenual ACC and ventral caudate/nucleus accumbens region and the hypothalamus.Limitations
Our study included a small, partially medicated patient cohort that precluded our ability to investigate sex or drug effects, evaluate behavioural differences between the groups and perform a whole-brain analysis.Conclusion
The ventral striatum and ventral frontal cortex were distinctly and differentially modulated in their connectivity with the subgenual ACC during the experience of sad mood in patients with OCD. These results suggest that, in patients with OCD, induced sadness appears to have provoked a primary subcortical component of the hypothesized “OCD circuit,” which may offer insights into why OCD symptoms tend to develop and worsen during disturbed emotional states. 相似文献99.
100.
Gulay Simsek Bagir Okan S. Bakiner Emre Bozkirli Gulhan Cavlak Hulya Serinsoz M. Eda Ertorer 《Medical principles and practice》2015,25(1):61-66