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   773篇
  免费   42篇
  国内免费   4篇
耳鼻咽喉   23篇
儿科学   12篇
妇产科学   23篇
基础医学   84篇
口腔科学   110篇
临床医学   62篇
内科学   169篇
皮肤病学   30篇
神经病学   60篇
特种医学   10篇
外科学   79篇
综合类   1篇
预防医学   85篇
眼科学   3篇
药学   44篇
中国医学   12篇
肿瘤学   12篇
  2023年   5篇
  2022年   11篇
  2021年   45篇
  2020年   35篇
  2019年   47篇
  2018年   53篇
  2017年   31篇
  2016年   24篇
  2015年   39篇
  2014年   35篇
  2013年   48篇
  2012年   70篇
  2011年   82篇
  2010年   39篇
  2009年   26篇
  2008年   49篇
  2007年   36篇
  2006年   33篇
  2005年   15篇
  2004年   22篇
  2003年   14篇
  2002年   11篇
  2001年   11篇
  2000年   9篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   3篇
  1992年   3篇
  1991年   3篇
  1989年   2篇
  1987年   1篇
  1985年   3篇
  1978年   2篇
  1976年   1篇
  1973年   1篇
  1965年   1篇
排序方式: 共有819条查询结果,搜索用时 31 毫秒
1.
Bulletin of Environmental Contamination and Toxicology - This work describes the development of an analytical protocol combining cleanup by liquid–solid extraction and GC–MS for the...  相似文献   
2.
3.
4.
AIM: The aim of this study was to evaluate the influence of four photoactivation systems [quartz tungsten halogen (QTH), light-emitting diode (LED), argon ion laser (AL), and plasma arc curing PAC)] on cementum/dentin and enamel microleakage of Class II restorations using a microhybrid [Z250-3M ESPE] and two packable composites [(SureFil-Dentsply and Tetric Ceram HB-Ivoclair/Vivadent]. METHODS AND MATERIALS: Three hundred sixty "vertical-slot Class II cavities" were prepared at the mesial surface of bovine incisors using a 245 carbide bur in a highspeed handpiece. Specimens were divided into twelve groups (composite-photoactivation systems). Half of the specimens had the gingival margin placed in enamel (n=15) and the other half in cementum/dentin (n=15). Composites were inserted and cured in 2 mm increments according to manufacturers' recommended exposure times. After polishing, the samples were immersed in 2% methylene blue solution, sectioned, and evaluated at the gingival margins. Data were submitted to statistical analysis using the Kruskal-Wallis and Mann-Whitney tests. RESULTS: No significant differences were found among the photoactivation systems and among resin composites (p>0.05). Microleakage was not significantly affected by location (enamel vs. cementum/dentin, p>0.05). These findings suggested neither the photoactivation systems nor the resin composite types might have an effect on the microleakage at gingival margins Class II cavities.  相似文献   
5.
PurposeThis study aimed to investigate the genetic cause of food-dependent Cushing syndrome (FDCS) observed in patients with primary bilateral macronodular adrenal hyperplasia (PBMAH) and adrenal ectopic expression of the glucose-dependent insulinotropic polypeptide receptor. Germline ARMC5 alterations have been reported in about 25% of PBMAH index cases but are absent in patients with FDCS.MethodsA multiomics analysis of PBMAH tissues from 36 patients treated by adrenalectomy was performed (RNA sequencing, single-nucleotide variant array, methylome, miRNome, exome sequencing).ResultsThe integrative analysis revealed 3 molecular groups with different clinical features, namely G1, comprising 16 patients with ARMC5 inactivating variants; G2, comprising 6 patients with FDCS with glucose-dependent insulinotropic polypeptide receptor ectopic expression; and G3, comprising 14 patients with a less severe phenotype. Exome sequencing revealed germline truncating variants of KDM1A in 5 G2 patients, constantly associated with a somatic loss of the KDM1A wild-type allele on 1p, leading to a loss of KDM1A expression both at messenger RNA and protein levels (P = 1.2 × 10–12 and P < .01, respectively). Subsequently, KDM1A pathogenic variants were identified in 4 of 4 additional index cases with FDCS.ConclusionKDM1A inactivation explains about 90% of FDCS PBMAH. Genetic screening for ARMC5 and KDM1A can now be offered for most PBMAH operated patients and their families, opening the way to earlier diagnosis and improved management.  相似文献   
6.
OBJECTIVES: We have comparatively evaluated respiratory burst and some steps of its signaling in human granulocytes towards different stimuli. MATERIALS AND METHODS: An alternative method to remove erythrocytes by dextran differential sedimentation was employed. Respiratory burst (RB) was assessed in a flow cytometer by the oxidation of a fluorescent probe (dichlorodihydrofluorescein). Stimuli were phorbol ester (PMA) and zymosan. RESULTS: Granulocytes obtained with dextran sedimentation mounted a normal RB for the two stimuli but cells obtained by erythrocyte lysis were ineffective to respond to zymosan (P < 0.05). EGTA did not affect PMA-induced, but inhibited zymosan-induced RB (P < 0.05). PMA-induced RB was blocked by a protein kinase C inhibitor (P < 0.05), whereas zymosan was not. Microfilament integrity was essential for zymosan but not for PMA, whereas microtubule depolymerization does not seem to be essential for both stimuli. Granulocytes obtained from recently diagnosed leukemia patients responded relatively well to both stimuli but after chemotherapy, the response to zymosan was increased whereas cells were unable to respond to PMA. CONCLUSION: The use of the proposed method allows the study of both RB and phagocytosis, making it useful to study these granulocyte responses in the clinical and experimental settings.  相似文献   
7.
8.

Background

Lynch syndrome (LS) diagnosis is underestimated, and most of the patients remain undetected after colorectal resections. The study aims to assess the frequency of LS in patients undergoing surgical treatment for colorectal cancer (CRC).

Methods

A total of 458 CRC patients were operated from January 2005 to December 2008. Positive CRC family history (FH) was present in 118 (25.8%) patients. Histologic sections were reviewed for microsatellite instability (MSI) criteria (Bethesda guidelines), immunohistochemical (IHC) analysis for MLH1, MSH2, MSH6, PMS2 proteins, through the avidin-biotin-peroxidase complex, MSI (BAT-25, BAT-26, NR-21, NR-24 and MONO-27) and BRAF somatic mutation.

Results

Of the 118 patients with FH, 61 (51.69%) met at least one of the revised Bethesda criteria. IHC was abnormal in 8 (13.1%) and MSI in 12 patients (20%). BRAF was negative in all cases. MSI histopathological included: intratumoral lymphocytes (47.5%), expansive tumors (29.5%) mucinous component (27.8%) and Crohn’s like reaction in (14.7%). There was an association between the revised Bethesda criteria with: sex, mucinous histology and Crohn’s like reaction; MSI and IHC with PMS2 and MLH1. Revised Bethesda criteria 4 had 10.6 increased chances to display positive MSI. We have proposed a score to contribute as a practical tool in the diagnosis of LS.

Conclusions

The frequence of LS in resected CRC patients was 2.6%. The criterion 4 Revised Bethesda was associated more strongly with the presence of MSI.  相似文献   
9.

Objective:

to investigate the association of risk factors with the Risk for aspiration nursing diagnosis and respiratory aspiration.

Method:

cross-sectional study assessing 105 patients with stroke. The instrument used to collect data addressing sociodemographic information, clinical variables and risk factors for Risk for aspiration. The clinical judgments of three expert RNs were used to establish the diagnosis. The relationship between variables and strength of association using Odds Ratio (OR) was verified both in regard to Risk for aspiration and respiratory aspiration.

Results:

risk for aspiration was present in 34.3% of the patients and aspiration in 30.5%. The following stood out among the risk factors: Dysphagia, Impaired or absent gag reflex, Neurological disorders, and Impaired physical mobility, all of which were statistically associated with Risk for aspiration. Note that patients who develop such a diagnosis were seven times more likely to develop respiratory aspiration.

Conclusion:

dysphagia, Impaired or absent gag reflex were the best predictors both for Risk for aspiration and respiratory aspiration.  相似文献   
10.

OBJECTIVE:

to verify associations between overweight and the characteristics of young adult students to support nursing care.

METHOD:

case-control study conducted with young adults from public schools. The sample was composed of 441 participants (147 cases and 294 controls, with and without excess weight, respectively). Sociodemographic and clinical characteristics were collected together with exposure factors and anthropometrics. Multiple logistic regression was used. The study received Institutional Review Board approval.

RESULTS:

statistically significant association with overweight: non-Caucasian, having a partner; weight gain during adolescence, mother''s excess weight, the use of obesogenic medication, augmented diastolic blood pressure, of abdominal circumference and waist/hip ratio. In addition to these, schooling and weight gain during childhood were also included in the multivariate analysis. After adjustment, the final model included: having a partner, weight gain during adolescence, augmented diastolic blood pressure and abdominal circumference.

CONCLUSION:

the analysis of predictor variables for excess weight among young adult students supports nurses in planning and developing educational practices aimed to prevent this clinical condition, which is a risk factor for other chronic comorbidities, such as cardiovascular diseases.  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