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   1086篇
  免费   30篇
  国内免费   6篇
耳鼻咽喉   34篇
儿科学   58篇
妇产科学   130篇
基础医学   89篇
口腔科学   51篇
临床医学   80篇
内科学   172篇
皮肤病学   36篇
神经病学   43篇
特种医学   40篇
外科学   241篇
综合类   17篇
预防医学   18篇
眼科学   39篇
药学   41篇
中国医学   2篇
肿瘤学   31篇
  2023年   6篇
  2022年   12篇
  2021年   23篇
  2020年   12篇
  2019年   28篇
  2018年   25篇
  2017年   18篇
  2016年   31篇
  2015年   41篇
  2014年   44篇
  2013年   65篇
  2012年   95篇
  2011年   88篇
  2010年   44篇
  2009年   63篇
  2008年   87篇
  2007年   104篇
  2006年   96篇
  2005年   78篇
  2004年   60篇
  2003年   36篇
  2002年   26篇
  2001年   13篇
  2000年   11篇
  1999年   8篇
  1998年   2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1122条查询结果,搜索用时 857 毫秒
21.
The aim of this study is to report clinical and imaging findings, and treatment outcomes of a patient with nodular posterior scleritis. A 41-year-old woman was diagnosed as nodular posterior scleritis in the light of clinical and imaging findings. At first admission best corrected visual acuity was 20/50 in her right eye. Fundus examination revealed an amelanotic subretinal mass under the superior temporal arcade associated with subretinal fluid surrounding it. B-scan ultrasonography, optical coherence tomography, fluorescein angiography, and indocyanine green angiography findings confirmed the diagnosis. As treatment, nepafenac eye drops 3 times a day, and flurbiprofen tablet 100 mg twice a day were prescribed. After 4 weeks of treatment, the ocular pain was relieved, BCVA improved to 20/20, and subretinal mass totally regressed. Although the diagnosis of nodular posterior scleritis may be confusing, it has to be kept in mind in patients with a subretinal/choroidal mass. Multimodal fundus imaging may be helpful in differential diagnosis. The condition is usually curable with non-steroidal anti-inflammatory drugs and/or systemic steroids.  相似文献   
22.
AIM:To investigate the effects of selective laser trabeculoplasty (SLT) on the main numerical parameters of anterior segment with Pentacam rotating Scheimpflug camera in patients with ocular hypertension (OHT) and primary open angle glaucoma (POAG).METHODS: Pentacam measurements of 45 eyes of 25 (15 females and 10 males) patients (12 with OHT, 13 with POAG) before and after SLT were obtained. Measurements were taken before and 1 and 3mo after SLT. Pentacam parameters were compared between OHT and POAG patients, and age groups (60y and older, and younger than 60y).RESULTS: The mean age of the patients was 57.8±13.9 (range 20-77y). Twelve patients (48%) were younger than 60y, while 13 patients (52%) were 60y and older. Measurements of pre-SLT and post-SLT 1mo were significantly different for the parameters of central corneal thickness (CCT) and anterior chamber volume (ACV) (P<0.05). These parameters returned back to pre-SLT values at post-SLT 3mo. Decrease of ACV at post-SLT 1mo was significantly higher in younger than 60y group than 60y and older group. There was no statistically significant difference in Pentacam parameters between OHT and POAG patients at pre- and post-treatment measurements (P>0.05).CONCLUSION:SLT leads to significant increase in CCT and decrease in ACV at the 1st month of the procedure. Effects of SLT on these anterior segment parameters, especially for CCT that interferes IOP measurement, should be considered to ensure accurate clinical interpretation.  相似文献   
23.
Uzuner  Selcuk  Durcan  Gizem  Sahin  Sezgin  Bahali  Kayhan  Barut  Kenan  Kilicoglu  Ali Guven  Adrovic  Amra  Bilgic  Ayhan  Kasapcopur  Ozgur 《Clinical rheumatology》2021,40(12):5025-5032
Clinical Rheumatology - Having a child with a chronic illness is a source of stress for the whole family, especially the primary caregiver. The aim of this study was to evaluate the associations...  相似文献   
24.
Purpose

Hypophysitis is a heterogeneous condition that includes inflammation of the pituitary gland and infundibulum, and it can cause symptoms related to mass effects and hormonal deficiencies. We aimed to evaluate the potential role of machine learning methods in differentiating hypophysitis from non-functioning pituitary adenomas.

Methods

The radiomic parameters obtained from T1A-C images were used. Among the radiomic parameters, parameters capable of distinguishing between hypophysitis and non-functioning pituitary adenomas were selected. In order to avoid the effects of confounding factors and to improve the performance of the classifiers, parameters with high correlation with each other were eliminated. Machine learning algorithms were performed with the combination of gray-level run-length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray-level co-occurrence entropy.

Results

A total of 34 patients were included, 17 of whom had hypophysitis and 17 had non-functioning pituitary adenomas. Among the 38 radiomics parameters obtained from post-contrast T1-weighted images, 10 tissue features that could differentiate the lesions were selected. Machine learning algorithms were performed using three selected parameters; gray level run length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray level co-occurrence entropy. Error matrices were calculated by using the machine learning algorithm and it was seen that support vector machines showed the best performance in distinguishing the two lesion types.

Conclusions

Our analysis reported that support vector machines showed the best performance in distinguishing hypophysitis from non-functioning pituitary adenomas, emphasizing the importance of machine learning in differentiating the two lesions.

  相似文献   
25.
OBJECTIVE: The purpose of this trial was to determine the spectrum of diseases with fever of unknown origin (FUO) in Turkey. METHODS: A prospective multicenter study of 154 patients with FUO in twelve Turkish tertiary-care hospitals was conducted. RESULTS: The mean age of the patients was 42+/-17 years (range 17-75). Fifty-three (34.4%) had infectious diseases (ID), 47 (30.5%) had non-infectious inflammatory diseases (NIID), 22 (14.3%) had malignant diseases (MD), and eight (5.2%) had miscellaneous diseases (Mi). In 24 (15.6%) of the cases, the reason for high fever could not be determined despite intensive efforts. The most common ID etiologies were tuberculosis (13.6%) and cytomegalovirus (CMV) infection (3.2%). Adult Still's disease was the most common NIID (13.6%) and hematological malignancy was the most common MD (7.8%). In patients with NIID, the mean duration of reaching a definite diagnosis (37+/-23 days) was significantly longer compared to the patients with ID (25+/-12 days) (p=0.007). In patients with MD, the mean duration of fever (51+/-35 days) was longer compared to patients with ID (37+/-38 days) (p=0.052). CONCLUSIONS: Although infection remains the most common cause of FUO, with the highest percentage for tuberculosis, non-infectious etiologies seem to have increased when compared with previous studies.  相似文献   
26.
Neurological Sciences - Alzheimer’s disease (AD) can be either sporadic or familial, and familial forms of AD accounts for only 5% of the cases. So far, autosomal dominantly inherited...  相似文献   
27.
Current evidence strongly suggests that aberrant activation of the nuclear factor kappa B (NF-kB) signaling cascade is connected to carcinogenesis. The matrix metalloproteinases (MMP) which are also the key agents for tumor metastasis may be potent candidates for tumor diagnosis in clinics. In this in vitro study, we hypothesized that metformin with an effective dose can inhibit tumor cell proliferation and metastasis by modulating the expressions of MMP-2 and -9 and interfering with NF-kB signaling in primary breast cancer cells (PBCCs). 300 000 cells per ml were obtained from biopsies of breast tumors from five human donors. The cell viability and proliferation were tested. Immunocytochemistry was performed for MMP-2, MMP-9, and NF-kB, and enzyme-linked immunosorbent assay for NF-kB activity, quantitative real-time PCR for RELA/p65, IkBα, MMP-2, and MMP-9. Three different doses of metformin (5, 10, and 25 mM) (Met) reduced the viability and proliferation of PBCCs in a dose-dependent manner, maximum inhibition was observed at 25 mM Met. The expression of RELA/p65 was not affected by 25 mM Met. Nuclear immunoreactivity and activity of NF-kB reduced while cytoplasmic NF-kB (p65) elevated by 25 mM Met compared to non-treatment (P < 0.05). The expression and immunoreactivity of MMP-9 but not MMP-2 were decreased by 25 mM Met treatment, compared with the non-treatment (P < 0.05). Metformin may have an essential antitumor role in the invasion and metastasis pathways of PBCCs by downregulating the MMP-9 expression blocking both the activity and nuclear translocation of NF-kB.  相似文献   
28.
29.
Background: To investigate changes in the levels and relative ratios of sclerostin, osteoprotegerin (OPG), and receptor activator of nuclear factor‐κB ligand (RANKL) in the gingival crevicular fluid (GCF) of patients with periodontitis after non‐surgical periodontal treatment. Methods: Fifty‐four individuals (27 healthy controls and 27 patients with chronic periodontitis [CP]) were enrolled in the study. Periodontitis patients received non‐surgical periodontal therapy. GCF sampling and clinical periodontal parameters were assessed before and 6 weeks after therapy. Sclerostin, OPG, and RANKL levels were measured by enzyme‐linked immunosorbent assay, and their relative ratios were calculated. Results: Total amounts and concentrations of sclerostin were significantly higher in patients with CP than in healthy individuals (P <0.025) and decreased after treatment (P <0.05). The RANKL/OPG ratio was significantly lower in healthy individuals than in patients with periodontitis before and after treatment (P <0.025), but no significant difference was observed in patients with periodontitis after treatment (P >0.05). The sclerostin/OPG and sclerostin/RANKL ratios were significantly lower in healthy individuals than in patients with periodontitis before and after treatment (P <0.025) and decreased in patients with periodontitis after treatment (P <0.05). Conclusions: The GCF sclerostin level may be more reliable than the RANKL/OPG ratio as a diagnostic and prognostic marker of periodontal disease and treatment outcome. Regulation of sclerostin levels may aid the development of new therapeutic strategies for the treatment of periodontal disease.  相似文献   
30.

PURPOSE

In this study, we aimed to evaluate the amount of marginal gap with two different substructure materials using identical margin preparations.

MATERIALS AND METHODS

Twenty stainless steel models with a chamfer were prepared with a CNC device. Marginal gap measurements of the galvano copings on these stainless steel models and Co-Cr copings obtained by a laser-sintering method were made with a stereomicroscope device before and after the cementation process and surface properties were evaluated by scanning electron microscopy (SEM). A dependent t-test was used to compare the mean of the two groups for normally distributed data, and two-way variance analysis was used for more than two data sets. Pearson''s correlation analysis was also performed to assess relationships between variables.

RESULTS

According to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 ± 5.82 µm before and 35.11 ± 6.52 µm after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 ± 8.87 µm before and 69.33 ± 9.03 µm after cementation. A highly significant difference (P<.001) was found in marginal gap measurements of galvano copings and a significant difference (P<.05) was found in marginal gap measurements of the laser-sintered Co-Cr copings. According to the SEM examination, surface properties of laser sintered Co-Cr copings showed rougher structure than galvano copings. The galvano copings showed a very smooth surface.

CONCLUSION

Marginal gaps values of both groups before and after cementation were within the clinically acceptable level. The smallest marginal gaps occurred with the use of galvano copings.  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