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   3286篇
  免费   151篇
  国内免费   37篇
耳鼻咽喉   67篇
儿科学   249篇
妇产科学   161篇
基础医学   318篇
口腔科学   106篇
临床医学   276篇
内科学   771篇
皮肤病学   129篇
神经病学   230篇
特种医学   112篇
外科学   544篇
综合类   50篇
预防医学   81篇
眼科学   108篇
药学   140篇
中国医学   6篇
肿瘤学   126篇
  2024年   3篇
  2023年   23篇
  2022年   39篇
  2021年   71篇
  2020年   44篇
  2019年   70篇
  2018年   87篇
  2017年   66篇
  2016年   122篇
  2015年   144篇
  2014年   130篇
  2013年   161篇
  2012年   225篇
  2011年   279篇
  2010年   139篇
  2009年   137篇
  2008年   278篇
  2007年   273篇
  2006年   293篇
  2005年   243篇
  2004年   214篇
  2003年   157篇
  2002年   122篇
  2001年   22篇
  2000年   23篇
  1999年   34篇
  1998年   12篇
  1997年   3篇
  1996年   4篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1992年   9篇
  1991年   5篇
  1990年   6篇
  1989年   2篇
  1987年   2篇
  1986年   1篇
  1985年   3篇
  1984年   3篇
  1982年   2篇
  1981年   1篇
  1979年   3篇
  1978年   5篇
  1977年   2篇
  1976年   1篇
  1974年   3篇
  1973年   1篇
排序方式: 共有3474条查询结果,搜索用时 15 毫秒
91.
92.
93.

Purpose

The aim of this study is to identify potential genes involved in human globozoopsermia.

Methods

Nineteen globozoospermic patients (previously screened for DPY19L2 mutations with no causative mutation) were recruited in this study and screened for mutations in genes implicated in human globozoospermia SPATA16 and PICK1. Using the candidate gene approach and the determination of Spata16 partners by Glutathione S-transferase (GST) pull-down four genes were also selected and screened for mutations.

Results

We identified a novel mutation of SPATA16: deletion of 22.6 Kb encompassing the first coding exon in two unrelated Tunisian patients who presented the same deletion breakpoints. The two patients shared the same haplotype, suggesting a possible ancestral founder effect for this new deletion. Four genes were selected using the candidate gene approach and the GST pull-down (GOPC, PICK1, AGFG1 and IRGC) and were screened for mutation, but no variation was identified.

Conclusions

The present study confirms the pathogenicity of the SPATA16 mutations. The fact that no variation was detected in the coding sequence of AFGF1, GOPC, PICK1 and IRGC does not mean that they are not involved in human globozoospermia. A larger globozoospermic cohort must be studied in order to accelerate the process of identifying new genes involved in such phenotypes. Until sufficient numbers of patients have been screened, AFGF1, GOPC, PICK1 and IRGC should still be considered as candidate genes.
  相似文献   
94.
Conclusion: IBCT technique should be preferred owing to its high graft survival rate and ABG gain. While no significant difference was found in middle ear pressures between ears that underwent IBCT and normal ears, compliance values were found to be decreased in patients undergoing IBCT. However, the lack of correlation between ABG gain and compliance values indicated that compliance increase had no effect on post-operative ABG results. Objective: The aim of the present study was to compare tympanometric and audiological parameters in patients undergoing inlay butterfly cartilage tympanoplasty (IBCT) with their normal ears and to determine their difference with normal ear tympanometric parameters. Methods: Overall, 25 patients that underwent an operation between August 2010–May 2014 were included in the present study. In 13 of these patients, the ear that did not undergo operation was normal. 0.5, 1, 2, 4?kHz pure sound average values, tympanometric measurements and compliance values of normal and operated ears were compared. Results: The graft survival rate in patients was found to be 92%. Mean pre-operative air–bone gap (ABG) was 16.4?±?5.4 in patients, while mean post-operative ABG was 10.9?±?5.8, with a statistically significant difference (p?=?0.001) While there was no significant difference between operated and normal ears of patients in terms of middle ear pressure (0.441), compliance values were significantly higher in normal ears than those in operated ears (0.032). When post-operative ABG gain was compared with compliance values, no significant correlation was found between ABG gain and compliance measurements (r?=??0.025 and p?=?0.936).  相似文献   
95.
96.
OBJECTIVES:Pleural effusion is a common diagnostic and clinical problem. The differential diagnosis of pleural effusion may be difficult and may require several procedures, including invasive ones. Certain studies have investigated biochemical parameters to facilitate the diagnosis of exudative pleural effusion; however, it remains a challenging problem in clinical practice. We aimed to investigate the potential role of the neutrophil-lymphocyte ratio, which can be easily obtained by determining the cell count of the pleural fluid, in the differential diagnosis of exudative pleural effusion.METHODS:Records from patients who underwent thoracentesis and pleural fluid analysis between May 1, 2013, and March 1, 2015, were obtained from the electronic database of our hospital. The patients who met the inclusion criteria were divided into five groups according to their diagnosis: malignant pleural effusion, para-malignant pleural effusion, para-pneumonic effusion, tuberculosis-related effusion or other. The neutrophil-lymphocyte ratio value was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. The patient groups were compared according to the given parameter.RESULTS:A total of 465 patients who met the inclusion criteria among 1616 patients with exudative pleural effusion were included in the study. The mean neutrophil-lymphocyte ratio value was significantly lower in tuberculosis-related pleural effusion compared to malignant, para-pneumonic and para-malignant effusions (p=0.001, p=0.001, p=0.012, respectively). The areas under the curve for tuberculosis pleurisy compared to malignant, para-pneumonic and para-malignant effusions were 0.38, 0.36, and 0.37, respectively. Lower cut-off values had higher sensitivity but lower specificity for tuberculosis pleurisy, while higher cut-off values had higher specificity but lower sensitivity for this condition.CONCLUSION:The pleural fluid neutrophil-lymphocyte ratio, which is an inexpensive, reproducible, and easily calculated hematological parameter, may facilitate the differential diagnosis of pleural effusion.  相似文献   
97.
We investigated the effects of long- and short-term interdisciplinary treatment approaches for reducing symptoms and improving health-related quality of life (HRQoL) and physical functions of patients with fibromyalgia and compared the effects of two different interdisciplinary treatment approaches. We conducted a prospective, randomized, controlled trial involving 66 women with fibromyalgia eligible for the study at a university hospital setting. The patients were randomized into three groups (allocation ratio 1:1:1) using a computer-generated random numbers: a long-term interdisciplinary treatment group (LG, n = 22) that participated in 10 sessions (3-h once-weekly session for 10 weeks) of cognitive behavioral therapy (CBT) together with exercise training and other fibromyalgia related educational programs (two full days); a short-term interdisciplinary treatment group (SG, n = 22) that received two full days of educational, exercise, and CBT programs; and a control group (CG, n = 22). The patients were evaluated at baseline and 6 months after treatment using the visual analog scale (pain, fatigue, and sleep), Fibromyalgia Impact Questionnaire, Beck Depression Inventory, Short Form-36, tender point numbers, and pressure algometry as primary outcomes. The statistical analysis was confined to the ‘per-protocol’ set. No blinding was performed. The number of patients analyzed was 21 in the LG, 19 in the SG, and 19 in the CG. The intensity of pain (p < 0.001), severity of fatigue (p = 0.048), number of tender points (p = 0.002), and pressure pain threshold (p = 0.012) decreased significantly in both the LG and SG groups compared with controls. Moreover, physical functions (p = 0.017) and physical components of the HRQoL (p = 0.036) improved significantly in the intervention groups compared with the controls. However, there was no significant difference between intervention groups and the control group at the end of study in terms of quality of sleep (p = 0.055), severity of depressive symptoms (p = 0.696), and mental components of the HRQoL (p = 0.229). Finally, with the exception of the severity of fatigue and physical components of the HRQoL, there was no obvious significant difference between the efficacies of the two treatment approaches when compared with controls; the long-term treatment was found more effective in reducing pain than the short-term. Both, long- and short-term interdisciplinary treatments were effective in reducing the severity of some symptoms and disease activity in patients with fibromyalgia. The short-term program well meets the needs of women with fibromyalgia particularly in relation to pain and health status as measured using FIQ; however, a long-term program may be beneficial in reducing fatigue and improving physical function to a higher extent.  相似文献   
98.
99.
We investigated the cytoprotective effect of melatonin in epirubicin-induced cardiotoxicity using four experimental groups of male Wistar rats: untreated control rats, epirubicin-treated rats, epirubicin+melatonin-treated rats, and melatonin-treated rats. We examined the histopathological and biochemical effects of melatonin on the epirubicin-induced changes and measured the levels of the lipid peroxidation end-product (malondialdehyde, MDA), an indicator of nitric oxide (NO) synthesis (nitrite/nitrate production), and reduced glutathione (GSH) in the heart. We also studied the extracellular matrix components (fibronectin, laminin) in the heart. Vacuole formation, mitochondrial deformation and degeneration, and disordered myofibrillary structures were detected ultrastructurally in the epirubicin-treated group. The degeneration was reduced in the heart tissues of the epirubicin+melatonin group. Epirubicin increased the nitrite/nitrate production, but did not change the MDA and GSH levels significantly. Melatonin treatment lowered the nitrite/nitrate concentrations, while increasing the GSH levels, which exceeded the levels in epirubicin+melatonin-treated rats. We conclude that the epirubicin increased the nitrozative stress, not the oxidative stress, in heart tissue, and the cardioprotective effect of melatonin was partially attributed to the suppression of epirubicin-induced nitrozative stress. These results suggest that melatonin partially protects against epirubicin-induced cardiotoxicity.  相似文献   
100.
Studies of visual function in behaving subjects require that stimuli be positioned reliably on the retina in the presence of eye movements. Fixational eye movements scatter stimuli about the retina, inflating estimates of receptive field dimensions, reducing estimates of peak responses, and blurring maps of receptive field subregions. Scleral search coils are frequently used to measure eye position, but their utility for correcting the effects of fixational eye movements on receptive field maps has been questioned. Using eye coils sutured to the sclera and preamplifiers configured to minimize cable artifacts, we reexamined this issue in two rhesus monkeys. During repeated fixation trials, the eye position signal was used to adjust the stimulus position, compensating for eye movements and correcting the stimulus position to place it at the desired location on the retina. Estimates of response magnitudes and receptive field characteristics in V1 and in LGN were obtained in both compensated and uncompensated conditions. Receptive fields were narrower, with steeper borders, and response amplitudes were higher when eye movement compensation was used. In sum, compensating for eye movements facilitated more precise definition of the receptive field. We also monitored horizontal vergence over long sequences of fixation trials and found the variability to be low, as expected for this precise behavior. Our results imply that eye coil signals can be highly accurate and useful for optimizing visual physiology when rigorous precautions are observed.  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