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   345篇
  免费   31篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   8篇
妇产科学   10篇
基础医学   48篇
口腔科学   11篇
临床医学   38篇
内科学   94篇
皮肤病学   6篇
神经病学   25篇
特种医学   10篇
外国民族医学   2篇
外科学   22篇
综合类   7篇
一般理论   1篇
预防医学   33篇
眼科学   20篇
药学   24篇
中国医学   6篇
肿瘤学   14篇
  2023年   8篇
  2022年   20篇
  2021年   19篇
  2020年   17篇
  2019年   24篇
  2018年   18篇
  2017年   19篇
  2016年   16篇
  2015年   16篇
  2014年   24篇
  2013年   24篇
  2012年   32篇
  2011年   27篇
  2010年   24篇
  2009年   10篇
  2008年   21篇
  2007年   15篇
  2006年   11篇
  2005年   10篇
  2004年   4篇
  2003年   2篇
  2002年   1篇
  2001年   2篇
  2000年   2篇
  1999年   4篇
  1998年   1篇
  1996年   1篇
  1995年   2篇
  1985年   2篇
  1984年   1篇
  1981年   1篇
  1969年   2篇
排序方式: 共有380条查询结果,搜索用时 15 毫秒
61.
AIM: To describe the involvement in relatives of keratoconus (KCN) patients with corneal topography map. · METHODS: A total of 150 siblings of 300 eyes of 75 KCN patients referred to corneal clinic were studied and experienced complete slit-lamp, refraction examinations and topographic cornea maps provided by videophotoker- atography. ANOVA, Fisher exact and Chi-square tests performed to compare of results. · RESULTS: Of 150 siblings, 56% were female and 44% were male with average age of 21 (range 15-39) years. KCN and suspect KCN diagnosed in 12.3% and 6.6% respectively. The central keratometry (CK) was 46.5±4.51 dioptr (D) in KCN and 45.66±1.52D in suspect KCN. Inferior-superior value (I-S) was 3.51±2.5D in KCN and 1.56±1.22D in suspect KCN. In KCN condition the oval pattern was 67.6% (n = 25) and Round pattern detected 32.4% (n =12). In suspect KCN these patterns detected 90% and 10% respectively. Refractive errors in KCN were -7.5 to +1.25 dioptr (-1.25±1.83), in suspect KCN 0.45 to -4.2 dioptr (-0.68±0.76) and in healthy group 2.75 to -7.5 dioptr (-0.6±1.12). Astigmatism was mild in 22.7%, moderate and sever astigmatism in 18.3% in KCN and suspect KCN · CONCLUSION: Increasing KCN condition in healthy siblings of KCN patients shows require to screening plan to early diagnose and cautionly treatment of contact lens in these individuals.  相似文献   
62.

Purpose

This article is a report of using seemingly unrelated regression (SUR) models to examine the determinants of different dimensions of quality of life (QoL) among childbearing age women. There are a limited number of studies on QoL and its associated factors among women in developing countries such as Iran. Therefore, more attention should be focused on identifying these issues.

Methods

We administered the Persian’s abbreviated version of the World Health Organization Quality of Life (WHOQOL-BREF) questionnaire to 1,067 married women aged between 15 and 49 years. The women were chosen via a multistage research design from the rural region of Shiraz, the center of Fars Province in Iran in 2008. Clinical and socio-demographic characteristics as well as their reproductive health-related characteristics were investigated. To identify associated factors of QoL dimensions, ordinary least squares (OLS) regression and SUR were used and their findings were compared.

Results

The WHOQOL-BREF showed acceptable consistency (Cronbach’s alpha range: 0.62–0.75 across domains). Lower age, absence of long-term illness, economic status satisfaction, higher level of education, lower number of pregnancies, and higher body mass index were important associated factors of different dimensions of the QoL among these women. The estimated parameters for these factors were in close agreement in both OLS and SUR estimation methods. However, the SUR estimator provided the higher precision of the estimates than the OLS estimator, as the parameters obtained by SUR are characterized by lower standard errors. Women’s age, income satisfaction, and level of education were common for all domains.

Conclusions

This study presents a novel approach to simultaneously predict QoL domains using the SUR estimators and the results are relevant for implementing objective QoL. SUR estimators performed consistently better than the OLS estimators, since SUR takes the correlation between error terms into account. Thus, the SUR method could be a useful methodology for predicting QoL domains.  相似文献   
63.
Prostate adenocarcinoma most often metastasis to the bones of spine and pelvis. Metastasis to the supradia-phragmatic lymph nodes as uncommon presentation of this disease has been increasingly reported...  相似文献   
64.
65.
Adequate daily water consumption is an important factor of keeping regular homeostasis. However, the best quantity of daily water consumption for a healthy individual is not virtually stated in the literature. Despite the dearth of evidence-based recommendations, it is commonly thought that ingesting eight glasses of water a day is good for a healthy person. Avicenna had a unique viewpoint. He believed that daily water intake depended on numerous elements together with age, intercourse, body temperament, season, occupation and various internal and external elements. He also cited a few essential and useful measures regarding proper water consumption, which have additionally been emphasized in Islamic hadiths.  相似文献   
66.
The electrochemical study of a tetrabromo-p-benzoquinone modified carbon paste electrode (TBQ-MCPE), as well as its efficiency for electrocatalytic oxidation of ascorbic acid, dopamine and uric acid, is described. Cyclic voltammetry was used to investigate the redox properties of this modified electrode at various solution pH values and at various scan rates. Three linear segments were found with slope values of ?58.4 mV/pH, ?28.1 mV/pH and 0.0 mV/pH in the pH range 2.0–7.1, pH 7.1–9.0 and pH 9.0–11.0, respectively. The apparent charge transfer rate constant, ks, and transfer coefficient, α, for electron transfer between TBQ and CPE were calculated as 3.79 ± 0.10 s?1 and 0.55, respectively. The electrode was also employed to study the electrocatalytic oxidation of AA, using cyclic voltammetry, chronoamperometry and differential pulse voltammetry as diagnostic techniques. It has been found that the oxidation of AA at the surface of TBQ-MCPE occurs at a potential of about 430 mV less positive than that of an unmodified CPE. The diffusion coefficient of AA was also estimated using chronoamperometry. The kinetic parameters such as the electron transfer coefficient, α, and heterogeneous rate constant, kh, for oxidation of AA at the TBQ-MCPE surface was determined using cyclic voltammetry. Differential pulse voltammetry (DPV) exhibits two linear dynamic ranges and a detection limit of 0.62 μM for AA. In DPV, the TBQ-MCPE could separate the oxidation peak potentials of AA, DA and UA present in the same solution, though at the unmodified CPE the peak potentials were indistinguishable. This modified electrode was quite effective not only to detect AA, DA and UA, but also in simultaneous determination of each component concentration in the mixture.  相似文献   
67.

Purpose

Spermatogonial stem cells are affected by the interactions of extrinsic signals produced by components of the microenvironment niche, in addition to the chemical and physical properties of the extracellular matrix. Therefore, this study was initiated to assess the interaction of these cells on a synthetic nanofibrillar extracellular matrix that mimicked the geometry and nanotopography of the basement membrane for cellular growth.

Methods

This study has used a variety of experimental approaches to investigate the interaction of mouse neonatal-derived spermatogonial stem-like cells on a synthetic random oriented three-dimensional nanofibrillar matrix composed of electrospun polyamide nanofibers (Ultra-Web™).

Results

Spermatogonial stem-like cell colonies were characterized by their ability to express α6-integrin, Thy-1, PLZF, and β1-integrin. After culture of cells on the nanofibrillar surfaces for 7 days, the number of colonies, the number of cells in each colony, and the average area of colonies were increased (P < 0.05). However, the expression difference of related markers in both groups was not significant. A significantly higher proliferation and survival was observed in the nanofibrillar group (P < 0.05). After transplantation into the testes of busulfan-treated adult mice, spermatogonial stem-like cell colonies that were cultured on the nanofibrillar surface demonstrated functionality, as verified by their ability to migrate to the seminiferous basal membrane, where they produced additional colonies.

Conclusions

These results have suggested that electrospun nanofibrillar surfaces could provide a more favorable microenvironment for in vitro short term culture of spermatogonial stem-like cell colonies.  相似文献   
68.

Purpose  

Recent studies indicated that there is a high density of small nerve fibers in the functional layer of the endometrium in women with endometriosis and that it can be used as a marker to detect endometriosis. In this study, the efficacy assessment of small nerve fibers’ density as a diagnostic marker was compared in patients with and without endometriosis.  相似文献   
69.
Obesity is a common problem in nutrition, both in the developed and developing countries. The aim of this study was to classify obesity by artificial neural networks and logistic regression. This cross-sectional study comprised of 414 healthy military personnel in southern Iran. All subjects completed questionnaires on their socio-economic status and their anthropometric measures were measured by a trained nurse. Classification of obesity was done by artificial neural networks and logistic regression. The mean age±SD of participants was 34.4?±?7.5?years. A total of 187 (45.2%) were obese. In regard to logistic regression and neural networks the respective values were 80.2% and 81.2% when correctly classified, 80.2 and 79.7 for sensitivity and 81.9 and 83.7 for specificity; while the area under Receiver-Operating Characteristic (ROC) curve were 0.888 and 0.884 and the Kappa statistic were 0.600 and 0.629 for logistic regression and neural networks model respectively. We conclude that the neural networks and logistic regression both were good classifier for obesity detection but they were not significantly different in classification.  相似文献   
70.
Renal lymphangiomatosis is an exceedingly rare disorder characterized by developmental malformation of the lymphatic system surrounding the kidneys. We report a case of bilateral renal lymphangiomatosis in a 21-year-old man who underwent abdominal sonographic examination that revealed numerous cystic areas of various sizes around both kidneys with extension along the renal hilum. Subsequent abdominal CT examination demonstrated bilateral, multilocular, fluid-filled cystic masses with thin walls in the perirenal and peripelvic region. MRI of the patient revealed bilaterally enlarged kidneys with multiple hyperintense lesions in both perirenal spaces and the peripelvic area on T2-weighted images. These cystic spaces appeared hypointense on T1-weighted images with no enhancement in postcontrast images. The diagnosis of renal lymphangiomatosis was made based on typical imaging findings.  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