全文获取类型
收费全文 | 10867篇 |
免费 | 816篇 |
国内免费 | 406篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 39篇 |
妇产科学 | 13篇 |
基础医学 | 852篇 |
口腔科学 | 4587篇 |
临床医学 | 537篇 |
内科学 | 460篇 |
皮肤病学 | 92篇 |
神经病学 | 1201篇 |
特种医学 | 195篇 |
外国民族医学 | 1篇 |
外科学 | 727篇 |
综合类 | 1456篇 |
预防医学 | 168篇 |
眼科学 | 13篇 |
药学 | 665篇 |
3篇 | |
中国医学 | 936篇 |
肿瘤学 | 112篇 |
出版年
2024年 | 10篇 |
2023年 | 200篇 |
2022年 | 207篇 |
2021年 | 386篇 |
2020年 | 380篇 |
2019年 | 343篇 |
2018年 | 305篇 |
2017年 | 336篇 |
2016年 | 362篇 |
2015年 | 360篇 |
2014年 | 683篇 |
2013年 | 624篇 |
2012年 | 633篇 |
2011年 | 754篇 |
2010年 | 555篇 |
2009年 | 436篇 |
2008年 | 526篇 |
2007年 | 558篇 |
2006年 | 500篇 |
2005年 | 439篇 |
2004年 | 382篇 |
2003年 | 355篇 |
2002年 | 323篇 |
2001年 | 292篇 |
2000年 | 224篇 |
1999年 | 190篇 |
1998年 | 185篇 |
1997年 | 142篇 |
1996年 | 136篇 |
1995年 | 117篇 |
1994年 | 128篇 |
1993年 | 129篇 |
1992年 | 108篇 |
1991年 | 92篇 |
1990年 | 89篇 |
1989年 | 76篇 |
1988年 | 71篇 |
1987年 | 50篇 |
1986年 | 69篇 |
1985年 | 85篇 |
1984年 | 56篇 |
1983年 | 41篇 |
1982年 | 38篇 |
1981年 | 30篇 |
1980年 | 40篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
目的 观察小鼠脊髓背根神经节细胞(DRGC)与人微血管内皮细胞(HMVEC)共培养对细胞增殖的影响,并探讨其机制.方法 分离培养小鼠DRGC,并与HMVEC进行共培养,设为DRGC组、HMVEC组、DRGC+ HMVEC组.噻唑蓝(MTT)法检测细胞增殖,实时定量聚合酶链反应(Real-time PCR)及Western blot检测血管内皮生长因子(VEGF)、神经生长因子(NGF)、增殖细胞核抗原(PCNA)和细胞周期蛋白D1(Cyclin Dl) mRNA及蛋白的表达.结果 细胞培养24h后,DRGC+ HMVEC组相对于DRGC组和HMVEC组的细胞增殖率分别为136.29%和137.45%,细胞增殖能力显著提高(P<0.05).VEGF、NGF、PCNA和Cyclin Dl mRNA和蛋白的表达在DRGC+HMVEC组中最高,与其他两组比较差异有统计学意义(P<0.05).结论 共培养DRGC和HMVEC能够促进VEGF和NGF的表达,并可能通过调控PCNA和Cyclin D1的表达促进共培养体系细胞增殖能力. 相似文献
62.
目的探讨改良TESSYS技术治疗腰椎神经根管狭窄症的安全性和有效性。方法对57例诊断为腰椎神经根管狭窄的患者采用改良TESSYS技术行腰椎神经根管减压术治疗,分别进行术前、出院时、术后3个月及末次随访VAS和ODI评分,评价疗效。结果术后患者的VAS和ODI评分均逐渐降低,术后各时段与术前相比较差异均有统计学意义(P0.01),术后各时段之间比较差异也均有统计学意义(P0.01)。根据ODI评分改善率分级,末次随访优良率为87.7%,有效率为94.7%。结论改良TESSYS技术治疗腰椎神经根管狭窄症减压充分、彻底,近期疗效满意,是一种安全、有效的微创术式。 相似文献
63.
64.
65.
目的:评价经三种根面处理剂脱矿的根面对人牙周膜细胞附着、增殖的影响。方法:收集因晚期牙周炎拔除的单根牙36个,经刮治、根面平整后,制备5mm×4mm大小的根片,随机分成24?TA组、枸橼酸组、米诺环素组和对照组,在处理后的根片上接种1×104个细胞。分别于接种1、3、5d后,各取3个根片固定、染色计数,分析各组的细胞附着和增殖程度。结果:24?TA、枸橼酸、2%米诺环素处理组接种1、3、5d后其根片上的细胞数明显高于对照组(P<0.05),而此三组之间无明显差异。结论:24?TA、枸橼酸、米诺环素能促进人牙周膜细胞的附着和增殖。 相似文献
66.
In vivo comparison of working length determination with two electronic apex locators 总被引:8,自引:0,他引:8
Wrbas KT Ziegler AA Altenburger MJ Schirrmeister JF 《International endodontic journal》2007,40(2):133-138
AIM: To compare the accuracy of two electronic apex locators (EALs) in the same teeth in vivo. METHODOLOGY: The working lengths in 20 teeth with a single canal were determined with two different EALs (Root ZX; J. Morita Corporation, Tokyo, Japan and Raypex 5 VDW, Munich, Germany) before extraction. When the first EAL was used the files were advanced until the display indicated the 'apical constriction'. The files were then fixed in removable and replaceable light curing composite patterns. The procedure was repeated in the same tooth with the second EAL and a different file. The teeth were then extracted and the apical 4 mm of the root canals were exposed. After that the apical parts with the repositioned files in the canals were digitally photographed under a light microscope. On the images the minor diameter and the major foramen of each sample were marked and the respective distances of the file tips from these positions were measured with a computer program. Subsequently the values of the two groups of EALs were compared using a paired sample t-test. RESULTS: The minor foramen was located within the limits of +/-0.5 mm in 75% of the cases with the Root ZX and in 80% of the cases with Raypex 5. The paired sample t-test showed no significant difference between the EALs regarding determination of the minor foramen. CONCLUSION: The use of EALs is a reliable method for determining working length. The differences between the two EALs were not statistically significant. 相似文献
67.
Background
Locally delivered doxycycline is found to be effective in managing periodontitis as an adjunct to scaling and root planing.Aim
To evaluate the effect of locally delivered doxycycline (10%) with scaling and root planing in the periodontal treatment of smokers and to compare it with scaling and root planing alone.Methods
Twelve smokers with chronic periodontitis and a pocket depth (⩾5 mm) on posterior teeth that bleed on probing were selected. Patients were randomly assigned to scaling and root planing (SRP) or scaling and root planing followed by local application of doxycycline (SRP-D). Plaque, bleeding on probing, gingival recession, clinical attachment level (CAL), and probing depth (PD) were recorded at the baseline, 6 and 12 weeks.Results
Both groups showed a significant reduction in Plaque, Bleeding on Probing and pocket depth at 6th and 12th week from the baseline. A statistically significant gain of attachment was observed in both groups after treatment. Even though the doxycycline group showed slightly higher attachment gain it was not statistically significant compared to the control group.Conclusion
The observations of the study reveal that the additional benefit of topical application of doxycycline as an adjunct to scaling and root planing in smokers is not convincing. However, further clinical studies may be necessary to substantiate the present observations. 相似文献68.
Pasternak Júnior B Teixeira CS Silva RG Vansan LP Sousa Neto MD 《Australian endodontic journal : the journal of the Australian Society of Endodontology Inc》2007,33(1):42-45
Variations in the dental anatomy are found in all teeth. Knowledge of these variations, particularly concerning the location and treatment of all canals, is very important for the success of the endodontic therapy. The purpose of this study is to present a clinical case of a maxillary second molar with three palatal canals, two mesio-buccal and one disto-buccal canal. This report serves to remind clinicians that such anatomical variations should be taken into account during endodontic treatment of the maxillary molars. 相似文献
69.
70.
AIM: To investigate the root and canal morphology of mandibular permanent teeth collected from an indigenous Turkish population. METHODOLOGY: A total of 1400 extracted mandibular permanent teeth were evaluated. The teeth were divided into seven groups as central incisors, lateral incisors, canines, first premolars, second premolars, first molars and second molars in order to evaluate their root canal configurations. Access cavities were prepared and pulp tissue removed using 5.25% sodium hypochlorite solution. The teeth were stored in 5% nitric acid solution for 5 days, then rinsed under running water for 4 h and placed in increasing concentrations of ethyl alcohol. The teeth were rendered transparent by immersion in xylene solution for 3 days until complete transparency was achieved. Following this procedure, India ink was injected in the root canal systems and their configurations were examined and compared with the classification of Vertucci. The following observations were made: (i) root canal classification of mandibular teeth; (ii) morphology of the mandibular permanent teeth. The classification of Vertucci was taken as a reference during the evaluation; however additional canal morphological types were evaluated as separate groups. RESULTS: The presence of a second canal was detected in 68% of mandibular central incisors and 63% of lateral incisors. Lateral canals were found in 6.5% of mandibular central incisors and in 13% of lateral incisors. Overall, 62% of mandibular first premolar teeth had a single canal whereas 71% of second premolars had a single canal. The mandibular first and second molar teeth exhibited similar root canal configurations except for a group of second molar teeth that had a single root and canal. CONCLUSIONS: The morphological characteristics of teeth in this Turkish population were consistent with those of other studies performed on different populations using similar methodology. 相似文献