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   1750篇
  免费   92篇
  国内免费   13篇
耳鼻咽喉   11篇
儿科学   57篇
妇产科学   42篇
基础医学   159篇
口腔科学   48篇
临床医学   169篇
内科学   292篇
皮肤病学   53篇
神经病学   116篇
特种医学   53篇
外科学   254篇
综合类   46篇
一般理论   1篇
预防医学   106篇
眼科学   79篇
药学   209篇
中国医学   25篇
肿瘤学   135篇
  2024年   4篇
  2023年   31篇
  2022年   65篇
  2021年   109篇
  2020年   71篇
  2019年   139篇
  2018年   97篇
  2017年   64篇
  2016年   83篇
  2015年   73篇
  2014年   83篇
  2013年   107篇
  2012年   138篇
  2011年   138篇
  2010年   68篇
  2009年   65篇
  2008年   77篇
  2007年   77篇
  2006年   72篇
  2005年   39篇
  2004年   37篇
  2003年   24篇
  2002年   25篇
  2001年   14篇
  2000年   7篇
  1999年   12篇
  1998年   4篇
  1997年   4篇
  1996年   3篇
  1995年   4篇
  1994年   3篇
  1993年   3篇
  1992年   19篇
  1991年   13篇
  1990年   9篇
  1989年   11篇
  1988年   12篇
  1987年   5篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   9篇
  1982年   4篇
  1981年   2篇
  1979年   5篇
  1975年   4篇
  1974年   4篇
  1971年   4篇
  1967年   1篇
  1965年   2篇
排序方式: 共有1855条查询结果,搜索用时 15 毫秒
81.
The United Arab Emirates (UAE) has undergone a significant change in its population and economy in the last decades and in parallel its healthcare system has evolved rapidly to provide advanced, innovative and world-leading care. At the forefront of this revolution in healthcare is the development of a multidisciplinary multimodality thoracic service provision, offered at quaternary referral hospitals amalgamating academics, training, research and innovation. Previously, thoracic service care was limited to single providers at various public and private hospitals, usually performing lower complexity cases. Most complex thoracic cases were repatriated outside the UAE. This practice was replaced with the opening of Cleveland Clinic Abu Dhabi (CCAD), in 2015, which created a multidisciplinary thoracic program. This included the start of a mini-invasive surgical and lung transplantation program. Since that time other public and private hospitals have emerged providing care in a similar model. The impact of these programs has been a decreased transfer of patients abroad for treatment. Under the umbrella of the Emirates Thoracic Society (ETS) a platform for greater collaboration aimed at improving patient care, potential research and physician education has been created. Direct links have been established with world-leading Thoracic surgery and Respiratory Medicine Centers facilitating this development and offering support and guidance. This article charts these changes in thoracic care in the recent past, present, and delineates plans for the future in the UAE.  相似文献   
82.
Acoustic resolution photoacoustic microscopy (AR-PAM) has gained much attention in the past two decades due to its high contrast, scalable resolution, and relatively higher imaging depth. Multimode optical fibers (MMF) are extensively used to transfer light to AR-PAM imaging scan-head from the laser source. Typically, peak-power-compensation (PPC) is used to reduce the effect of pulse-to-pulse peak-power variation in generated photoacoustic (PA) signals. In MMF, the output intensity profile fluctuates due to the coherent nature of light and mode exchange caused by variations in the bending of the fibers during scanning. Therefore, using a photodiode (PD) to capture a portion of the total power of pulses as a measure of illuminated light on the sample may not be appropriate for accurate PPC. In this study, we have investigated the accuracy of PPC in fiber-guided and free-space AR-PAM systems. Experiments were conducted in the transparent and highly scattering medium. Based on obtained results for the MMF-based system, to apply PPC to the generated PA signals, tightly focused light confocal with the acoustic focus in a transparent medium must be used. In the clear medium and highly focused illumination, enhancement of about 45% was obtained in the homogeneity of an optically homogeneous sample image. In addition, it is shown that, as an alternative, free-space propagation of the laser pulses results in more accurate PPC in both transparent and highly scattering mediums. In free-space light transmission, enhancement of 25-75% was obtained in the homogeneity of the optically homogeneous sample image.  相似文献   
83.
Hydatid disease is a parasitic infection commonly involving the liver, less frequently the lungs, and rarely the kidneys. Reports on renal hydatid disease are limited in literature. In this case study, we share a case of a 37-year-old female who presented with a 3-month history of left flank pain and following further evaluation with laboratory testing and radiological imaging was revealed to be a case of renal hydatid disease. The patient was successfully managed surgically with left total nephrectomy. The study will focus on the findings of renal hydatid disease in radiological imaging modalities.  相似文献   
84.
White matter (WM) degeneration is an important feature of Huntington’s disease (HD) neuropathology. To investigate WM degeneration we used Diffusion Tensor Imaging and Tract-Based Spatial Statistics to compare Fractional Anisotropy, Mean Diffusivity (MD), parallel diffusivity and perpendicular diffusivity (λ⊥) in WM throughout the whole brain in 17 clinically diagnosed HD patients and 16 matched controls. Significant WM diffusivity abnormalities were identified primarily in the corpus callosum (CC) and external/extreme capsules in HD patients compared to controls. Significant correlations were observed between motor symptoms and MD in the CC body, and between global cognitive impairment and λ⊥ in the CC genu. Probabilistic tractography from these regions revealed degeneration of functionally relevant interhemispheric WM tracts. Our findings suggest that WM degeneration within interhemispheric pathways plays an important role in the deterioration of cognitive and motor function in HD patients, and that improved understanding of WM pathology early in the disease is required.  相似文献   
85.
In two groups of mice infected with 60 (group I) and 120 (group II) Schistosoma mansoni cercariae, respectively, the effects of intensity and duration of infection, and of praziquantel therapy (curative vs subcurative dose) on the levels of circulating anodic antigen (CAA), were studied. CAA was measured in trichloracetic acid-treated serum samples with an avidin-biotin enzyme-linked immunosorbent assay (AB-ELISA) using the monoclonal anti-CAA antibody. Total worm burdens, oogram patterns and ova counts/g liver and intestine were followed up. The lowest detectable level of CAA was about 1.0 ng/ml, and was positive with a worm load of 3-5/mouse. CAA levels became already detectable as early as 1-2 weeks post-infection (pi) before any parasitological parameter and showed a significant drop from the 11th-12th week pi onwards. A positive correlation was demonstrated between the CAA level and worm load. Following successful praziquantel therapy, CAA disappeared earlier than any of the other parameters studied.  相似文献   
86.
IntroductionA strong association between cardiovascular risk factors and erectile dysfunction (ED) was suggested. Coronary artery bypass grafting (CABG) is the gold standard for surgical myocardial revascularization.AimWe herein evaluate the impact of vascular risk factors on postoperative sexual functions in patients undergo CABG.Main Outcome MeasuresED severity by the International Index of Erectile Function (IIEF-5) and penile duplex study.MethodsThe present study included 100 patients who underwent CABG. The patients were evaluated by an abridged form of the IIEF-5 questionnaire, followed by CABG. Six months after surgery the erectile function of all patients was revaluated utilizing the IIEF-5.ResultsNumber of risk factors was significantly associated with postoperative change in IIEF-5 score (P = 0.02). A post hoc analysis of the association revealed that patients with one risk factor were significantly more likely to have increased IIEF-5 scores (N = 18), whereas those with two or more risk factors were significantly more likely to have decreased IIEF-5 scores (N = 21, P < 0.05). Furthermore, those with no risk factors were significantly more likely to be stable (N = 8) compared with those with more than two risk factors, who were more likely to have decreased scores (P < 0.05). The hierarchical logistic regression results showed that when examining all risk factors simultaneously, because of multicollinearity, only hyperlipidemia was significantly associated with postoperative ED (odds ratio [OR] = 11.33, confirdence interval [CI] = 1.25, 102.82). Frequency of intercourse was also significantly associated with postoperative ED after controlling for risk factors (OR = 0.71, CI = 0.52, 0.97).ConclusionsThis data clearly shows that the number of cardiovascular risk factors is an essential predictive factor for sexual function following surgery. Only hyperlipidemia may play a predictive role for the future sexual function of patients undergo CABG. Mohamed OA, Hamed HA, Roaiah MF, Helmy T, Mahran A, and Bennett CJ. Vascular risk factors as predictors of sexual function following coronary artery bypass graft. J Sex Med 2009;6:2017–2023.  相似文献   
87.
IntroductionErectile dysfunction and ischemic heart disease are common health problems that affect elderly individuals. Despite advances in treatment strategies, cardiopulmonary bypass (CPB) has been used for coronary artery bypass grafting (CABG) for over three decades for surgical myocardial revascularization.AimTo discuss the difference between the on pump and the newer alternative—the off-pump CABG (OPCABG) surgery—on the sexual function.MethodsThis prospective study included 100 patients who underwent CABG.Main Outcome MeasuresThe patients were evaluated by an abridged form of International Index of Erectile Function questionnaire (IIEF-5), Pharmaco-Penile Duplex Ultrasound and finally by the European System for Cardiac Operative Risk Evaluation. The patients were underwent either on-pump CABG or OPCABG. Six months after surgery, the erectile function was revaluated according to the same preoperative measures.ResultsPatients included in the study were classified into two matched groups: group I—patients who underwent on-pump CABG (N = 50); and group II—patients who underwent OPCABG (N = 50). The frequency of intercourse was significantly higher in OPCABG (P < 0.05) after surgery. The mean ± standard deviation of the IIEF-5 scores of the on-pump group postoperatively became 12.48 ± 7.19 whereas it became 15.88 ± 6.67 in the off-pump group (P < 0.05). Moreover, the number of patients who reported postoperative improvement of their IIEF-5 score was significantly higher in OPCABG group (N = 23) compared with the conventional on-pump CABG group (N = 13) (P < 0.05). There was no significant change in the duplex ultrasound after surgery between both groups.ConclusionsThe OPCABG has a diminished impact on the sexual function of patients compared with the conventional on-pump CABG. Therefore, the type of operation can be considered a predictive factor of sexual function following CAB surgery. Mohamed OA, Bennett CJ, Farid RM, Helmy T, Mahran A, and Hamed HA. The impact of on-pump coronary artery bypass surgery vs. off-pump coronary artery bypass surgery on sexual function. J Sex Med **;**:**–**.  相似文献   
88.
In an attempt to detect asymptomatic endometrial adenomatous hyperplasia in postmenopausal women, 40 cases were subjected to progesterone challenge test (PCT), measurement of serum estrogen and endometrial curettage. Group A (n = 30) included asymptomatic postmenopausal women, while group B (control group; n = 10) were cases with adenomatous hyperplasia (AH) diagnosed by biopsy. PCT showed a 100% sensitivity, 92% specificity, 71.4% predictive value of a positive test and 100% predictive value of a negative test in the detection of AH. Mean serum concentrations of E1 and E2 were significantly higher in patients with AH compared to cases with other endometrial histologies. Serum E1 and E2 and PCT can be used as screening tests to identify postmenopausal women with endometrial AH and thus at a greater risk of developing carcinoma.  相似文献   
89.
Physical and hormonal profile of male sexual development in epilepsy   总被引:3,自引:2,他引:1  
PURPOSE: This study was designed to investigate the effect of epilepsy and antiepileptic drugs (AEDs) on both the physical and hormonal aspects of the sexual development of male patients with epilepsy. METHODS: One hundred thirty male subjects with epilepsy, their age ranging between 8 and 18 years (mean, 14 +/- 2.9 years), entered the study; all were taking AEDs. Anthropometric measurements [height, weight, and body mass index (BMI)], testicular volume, penile length, and pubarche were assessed in the studied groups, as well as measurement of the levels of testosterone (T), free testosterone (FT), estradiol (E2), lutenizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin (PRL), and the results were compared with those of a control group. RESULTS: In this study, male patients older than 16 years were significantly shorter than their matched controls. The mean values of testicular volume and penile length were significantly lower in the patients in the different age subgroups, and the pubic hair staging (pubarche) was delayed in the patients older than 16 years. The mean values of total testosterone, estradiol, LH, and FSH serum levels were significantly higher, whereas the mean values of free testosterone, total-T/E2, total. T/LH, and FT/E2 ratios were lower in the patient subgroups compared with their age-matched controls. There were no significant changes in the mean basal PRL serum levels in the patients compared with the controls. The present study demonstrated a reduction in the testicular volume and penile length, significantly lower mean values of free testosterone and total-T/E2, and a higher mean value of E2 in the patients receiving polytherapy in the age subgroup older than 16 years compared with those on monotherapy; however, there was no demonstrable effect of seizure control or the duration of illness in any of the studied parameters. CONCLUSIONS: There is a delay in the sexual development of male patients with epilepsy in the different age subgroups, with endocrine changes in the form of increase in the total testosterone, but the free testosterone is lower, and an increase in estradiol, with lower T/LH levels. Patients receiving polytherapy, especially those older than 16 years, were more likely to have delayed gonadarch and disturbances in their hormonal profile.  相似文献   
90.
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