首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   796篇
  免费   19篇
  国内免费   6篇
耳鼻咽喉   30篇
儿科学   39篇
妇产科学   99篇
基础医学   73篇
口腔科学   39篇
临床医学   58篇
内科学   114篇
皮肤病学   4篇
神经病学   35篇
特种医学   36篇
外科学   184篇
综合类   12篇
预防医学   14篇
眼科学   20篇
药学   38篇
中国医学   2篇
肿瘤学   24篇
  2023年   5篇
  2022年   5篇
  2021年   18篇
  2020年   11篇
  2019年   20篇
  2018年   11篇
  2017年   14篇
  2016年   19篇
  2015年   31篇
  2014年   27篇
  2013年   49篇
  2012年   66篇
  2011年   60篇
  2010年   34篇
  2009年   57篇
  2008年   68篇
  2007年   77篇
  2006年   82篇
  2005年   61篇
  2004年   46篇
  2003年   24篇
  2002年   10篇
  2001年   8篇
  2000年   4篇
  1999年   7篇
  1998年   1篇
  1997年   1篇
  1995年   1篇
  1990年   2篇
  1988年   1篇
  1974年   1篇
排序方式: 共有821条查询结果,搜索用时 31 毫秒
1.
2.
European Archives of Oto-Rhino-Laryngology - As a graft material cartilage produces an excellent anatomical result with a low risk of re-perforation. However, there is a controversy among surgeons...  相似文献   
3.
Duchenne muscular dystrophy (DMD) has been found to be associated with cognitive impairment. However, few studies have addressed cognitive impairment among mothers of children with DMD. In the present study, the neuropsychological profiles of both carrier mothers (C-Ms) and noncarrier mothers (NC-Ms) were examined, and the findings were compared with healthy control mothers (HC-Ms). There were 90 participants, consisting of 31 C-Ms, 24 NC-Ms, and 35 HC-Ms, each of whom completed a neuropsychological test battery. C-Ms had poorer cognition performance in attention, working memory, immediate verbal memory, visuospatial skills, and executive functions than NC-Ms, and HC-Ms. This study provides evidence that there may be cognitive impairment in mothers of patients with DMD. The cognitive impairment of C-Ms has similarities to that seen in children with DMD.  相似文献   
4.
Determination of risk of severe bacterial infection complication in children with cancer is important to diminish the cost of hospitalization and therapy. In this study, children with cancer (leukemia excluded) were evaluated for risk of severe infection complication, success of therapy and the relation between clinical and inflammatory parameters during neutropenic fever attacks. Children who fulfilled the criteria of neutropenic fever with cancer were enrolled in the study. During admission, together with clinical and laboratory parameters; interleukin-6, interleukin-8, soluble tumor necrosis factor receptor II, and soluble interleukin 2 reseptor ve procalcitonin levels were detected. Empirical therapy was started with piperacillin/tazobactam and relation between the inflammatory cytokine levels and therapy response parameters were evaluated. The study population included 31 children and 50 neutropenic attacks were studied. In 48% of the attacks, absolute neutrophile count was >100/mm3 and infectious agents were shown microbiologically in 12% of the attacks. In the study group with piperacillin/tazobactam monotherapy, the success rate without modification was 58%. In the therapy modified group mean duration of fever, antibiotherapy and hospitalization were significantly longer than the group without modification. Inflammatory cytokines’ levels during admission (interleukin-6, interleukin-8, soluble tumor necrosis factor reseptor II) were higher in patients with fever >3 days and in multiple regression analysis, it has been shown that they have a determinative role on fever control time. Other cytokines did not show any significant relationship with risk of severe bacterial infection complication and success of therapy.  相似文献   
5.
Fusion is developmental anomaly of the dental hard tissue and is defined as the joining of 2 developing tooth germs resulting in a single large tooth structure. Different treatment methods can be used according to the requirements of the situation. The purpose of this case report was to present the multidisciplinary treatment of a patient who had a permanent maxillary left central tooth fused with a supernumerary incisor and a macrodont permanent maxillary right lateral incisor. In the radiographic evaluation, it was determined that the fused tooth had 2 separate roots. The supernumerary tooth was extracted after hemisection, and endodontic treatment was performed on the remaining portion. The distal side of the macrodont lateral incisor was recontoured, and the right central incisor was reshaped with a strip crown to provide aesthetic appearance and to gain space for the alignment of teeth. Following the restoration of the incisors, orthodontic treatment was provided.  相似文献   
6.
Etch-and-rinse adhesives can cause vasorelaxation via mechanisms occurring in the endothelium and smooth muscle, including the release of nitric oxide (NO). This effect might promote or aggravate bleeding if such adhesives are placed inadvertently on iatrogenic pulp microexposures. The present study assessed the vasoactive potential of a newer generation self-etch adhesive, Clearfil Protect Bond (CPB), on isolated rat aorta. Cumulative concentrations of the primer, bond, and mixture of CPB elicited concentration-dependent relaxation of phenylephrine-induced active tonus in the rat aorta, demonstrating that the tested self-etch adhesive can lead to vasorelaxation of pulp vessels that is mediated by Ca(2+) antagonistic effect. The vasorelaxant effect of CPB or its components was mediated neither via endothelium-dependent NO and prostanoid-dependent mechanisms nor by K(+) efflux through K(+) channels. Mechanical removal of the endothelium did not significantly alter the relaxation induced by CPB. Assuming these data can be extrapolated to the clinical situation, CPB, either in mixed form or by its components, can lead to vasorelaxation of pulp vessels that is mediated by a Ca(2+) antagonistic effect. If CPB is placed inadvertently on pulp microexposures during direct pulp capping, this effect might promote bleeding that might impair healing and, via plasma exatravasation, might compromise resin infiltration and polymerization.  相似文献   
7.

Introduction

Biocompatibility of pulp capping materials is important for successful use in dentistry. These materials should be nontoxic and permissive for proliferation and induction of odontogenic differentiation of pulp cells. The aim of our study was to evaluate the effects of enamel matrix derivative (EMD), mineral trioxide aggregate (MTA), and calcium hydroxide-containing cement (DYCAL) on proliferation and odontogenic differentiation of human tooth germ stem cells (hTGSCs) in which cells belonging to both pulp tissue and dental follicle exist.

Methods

The 96-well plates, 24-well plates, and special chamber slides were coated with biomaterials for cell proliferation, differentiation, and scanning electron microscopy analysis. Odontogenic differentiation of hTGSCs was evaluated by analyzing mRNA expression of dentin sialophosphoprotein (DSPP) by real-time polymerase chain reaction expression analysis, measurement of alkaline phosphatase activity, and visualization of calcium depositions by von Kossa staining.

Results

Our results demonstrate that EMD is the best material in terms of inducing differentiation and proliferation of hTGSCs. DYCAL was found to be toxic to hTGSCs; however, EMD-coated DYCAL showed less toxicity. EMD-coated MTA was not efficient at inducing proliferation and differentiation.

Conclusions

Pulp capping materials come in direct contact with dental pulp cells; thus, they require comprehensive evaluation of interactions between cells and biomaterials. Therefore, we cultured hTGSCs, capable of odontogenic differentiation, on pulp capping materials directly. Our results suggest that combination of capping materials with EMD would increase the quality of capping by increasing biocompatibility of capping materials.  相似文献   
8.

Objective:

The aim of this study was to evaluate the degree of microbial contamination in packaged gutta-percha cones before and during use in clinical conditions.

Material and Methods:

Sealed packages of #15-40 gutta-percha cones were opened under aseptic laboratory conditions. Two gutta-percha cones from each size were randomly drawn and added to tubes containing glass beads and 750 μL of saline. The tubes were vortexed, serially diluted and samples of 250 μL were cultured on agar plates. The plates were incubated at 37°C for 3 days and colonies were counted. The initially sampled packages were distributed to 12 final year dental students. The packages were collected at the end of the first and the third clinical practice days and sampled as described above.

Results:

Baseline microbial counts did not exceed 3 CFU. At the end of the first and the third day, additional contamination was found in five and three of the packages, respectively. The ratio of contaminated packages at the first day and the third day was not significantly different (z-test; p > 0.05). The numbers of microorganisms cultured at the first day (8 ± 9.9 CFU) and the third day (4.5 ± 8.3 CFU) were not significantly different (Wilcoxon signed-rank test; p > 0.05). No significant correlation was found between the number of filled root canals and cultured microorganisms at either the first day (Spearman''s rho; r = 0.481, p = 0.113) or the third day (r = -0.034, p = 0.917).

Conclusions:

Gutta-percha cones taken directly from manufacturer''s sealed package harbored microorganisms. Clinical use of the packages has been found to be associated with additional contamination of the gutta-percha cones. The counts of cultured microorganisms did not correlate well with the number of filled root canals.  相似文献   
9.

Introduction

The aim of this study was to test the dentinal tubule penetration of AH26 (Dentsply DeTrey, Konstanz, Germany) and MTA Fillapex (Angelus, Londrina, PR, Brazil) in instrumented root canals obturated by using cold lateral compaction or warm vertical compaction techniques in either the presence or absence of the smear layer.

Methods

Forty-five extracted single-rooted human mandibular premolar teeth were used. The crowns were removed, and the root canals were instrumented by using the Self-Adjusting File (ReDent-Nova, Ra'anana, Israel) with continuous sodium hypochlorite (2.6%) irrigation. Final irrigation was either with 5% EDTA or with sodium hypochlorite. The canals were dried and obturated by using rhodamine B–labeled AH26 or MTA Fillapex in combination with the cold lateral compaction or the warm vertical compaction technique. After setting, the roots were sectioned horizontally at 4-, 8-, and 12-mm distances from the apical tip. On each section, sealer penetration in the dentinal tubules was measured by using confocal laser scanning microscopy.

Results

Regardless of the usage of EDTA, MTA Fillapex, compared with AH26, was associated with greater sealer penetration when used with the cold lateral compaction technique, and, conversely, AH26, compared with MTA Fillapex, was associated with greater sealer penetration when used with the warm vertical compaction technique (P < .05). Removal of the smear layer increased the penetration depth of MTA Fillapex used with the cold lateral compaction technique (P < .05); however, it had no significant effect on the penetration depth of AH26.

Conclusions

Greater sealer penetration could be achieved with either the MTA Fillapex–cold lateral compaction combination or with the AH26–warm vertical compaction combination. Smear layer removal was critical for the penetration of MTA Fillapex; however, the same did not hold for AH26.  相似文献   
10.
In Turkey, "Maras Powder," which is a kind of powder yielded from the shields of tobacco, is widely used as smokeless tobacco through buccal mucosa or together with cigarette. Maras powder, composed of ash and a plant named Nicotiana Rustica Linn, is sometimes used to give up smoking. The present study was aimed to investigate the effects of Maras powder use on respiratory functions of healthy subjects who do not have any chronic disease. We found statistically significant differences in percentage of forced expiratory volume in the first second (FEV(1)%) (p = 0.001), the ratio of FEV(1) to forced vital capacity (FEV(1)/FVC) (p = 0.024), percent of maximum expiratory flow rate (FEF(25-75)%) (p = 0.002) and percent of peak expiratory flow (PEF%) (p = 0.037) between cigarette smokers with Maras powder use (n = 23) and control subjects (n = 24). Likewise, when cigarette smokers (n = 24) and control subjects were compared, the differences for all these parameters were significant (p = 0.022, p = 0.048, p = 0.011 and p = 0.047, respectively). Only FEV(1)% and FEF(25-75)% were significantly lower in cigarette smokers with Maras powder use than in Maras powder users (n = 28) (p = 0.011 and p = 0.022, respectively). There was a negative correlation between forced vital capacity and Maras powder use (r = -0.315, p = 0.03). The present study suggests that Maras powder does not cause serious bronchial obstruction. This may be due to usage of the smokeless tobacco through buccal mucosa but not through inhalation as in case of cigarette smoking.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号