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   427篇
  免费   13篇
  国内免费   2篇
儿科学   6篇
妇产科学   31篇
基础医学   26篇
口腔科学   11篇
临床医学   29篇
内科学   122篇
皮肤病学   4篇
神经病学   28篇
特种医学   67篇
外科学   30篇
综合类   2篇
预防医学   31篇
眼科学   11篇
药学   20篇
中国医学   1篇
肿瘤学   23篇
  2023年   4篇
  2022年   14篇
  2021年   22篇
  2020年   2篇
  2019年   6篇
  2018年   12篇
  2017年   1篇
  2016年   5篇
  2015年   4篇
  2014年   13篇
  2013年   7篇
  2012年   12篇
  2011年   29篇
  2010年   14篇
  2009年   10篇
  2008年   29篇
  2007年   27篇
  2006年   23篇
  2005年   29篇
  2004年   27篇
  2003年   28篇
  2002年   32篇
  2001年   7篇
  2000年   10篇
  1999年   9篇
  1998年   4篇
  1997年   3篇
  1996年   10篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   3篇
  1991年   4篇
  1990年   7篇
  1989年   6篇
  1988年   5篇
  1987年   4篇
  1986年   1篇
  1985年   4篇
  1984年   3篇
  1983年   1篇
  1981年   1篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有442条查询结果,搜索用时 15 毫秒
1.
OBJECTIVE: Constitutional delay of puberty (CDP) is the absence of secondary sexual features in otherwise healthy girls past the 13th year of life. The aim of the present work was to follow the development of estrogen-dependent sexual features, determine the concentrations of gonadotropins, estradiol and sex hormone-binding globulin (SHBG) in girls with CDP at menarche and compare the findings with normal controls. METHODS: We enrolled 11 girls with CDP and 40 controls. Primary, secondary and tertiary sexual features were studied at menarche +/- 3 months. The size of the ovaries and uterus was measured using transabdominal ultrasound. Maturation of breasts and pubic hair was staged according to Tanner. Concentrations of gonadotropins (follicle-stimulating hormone (FSH), luteinizing hormone) and estradiol were measured with immunoenzymatic methods. For measurement of SHBG, a radioimmunoassay was applied. RESULTS: Menarche in CDP girls usually appeared with Stage IV or V of breast development and Stage IV of pubic hair development according to Tanner. CDP girls demonstrated a significantly smaller volume of the uterine body at menarche compared with controls (p = 0.0004). Significantly lower levels of FSH (p = 0.0363) and estradiol (p = 0.0332), as well as a tendency towards lower levels of SHBG, were revealed in CDP girls at menarche. CONCLUSION: In CDP girls, menarche is accompanied by more mature tertiary sexual features, apparently resulting from longer exposure of estrogen-dependent tissues to the action of bioactive endogenous estrogens. The smaller volume of the uterine body in CDP girls at menarche may be attributed to decreased concentrations of FSH and estradiol, as well as to the possibility of decreased insulin-like growth factor-1 and increased neuropeptide Y levels.  相似文献   
2.
3.
Book review     
  相似文献   
4.
The cannabinoid system and immune modulation   总被引:13,自引:0,他引:13  
  相似文献   
5.
Evidence indicates that malnutrition very frequently co-occurs with chronic heart failure (HF) and leads to a range of negative consequences. Studies show associations between malnutrition and wound healing disorders, an increased rate of postoperative complications, and mortality. In addition, considering the increasing age of patients with HF, a specific approach to their treatment is required. Guidelines proposed by the European Society of Cardiology (ESC) for treating acute and chronic HF refer to the need to monitor and prevent malnutrition in HF patients. However, the guidelines feature no strict nutritional recommendations for HF patients, who are at high nutritional risk as a group, nor do they offer any such recommendations for the poor nutritional status subgroup, for which high morbidity and mortality rates have been observed. In the context of multidisciplinary healthcare, recommended by the ESC and proven by research to offer multifaceted benefits, nutritional status should be systematically assessed in HF patients. Malnutrition has become a challenge within healthcare systems and day-to-day clinical practice, especially in developed countries, where it affects the course of disease and patients’ prognosis.  相似文献   
6.

Purpose

We report here a unique case of a sudden loss of vision as the first symptom of an advanced chronic nephropathy.

Methods and Results

A 25-year-old man was referred to the Department of Ophthalmology with sudden visual deterioration presumptively diagnosed as bilateral retinitis. The patient had never been under any medical care before and had never had any clinical signs of any chronic disease. He underwent an ophthalmic examination with optical coherence tomography (OCT). Based on the clinical features, OCT scans and systemic blood pressure (BP) assessment (225/145 mm Hg), the patient was definitely diagnosed with hypertensive retinopathy and choroidopathy due to hypertensive crisis. After urgent diagnostic procedures, the patient was diagnosed with a chronic kidney disease at stage 5 in the course of chronic glomerulonephritis. Immediately, a renal replacement therapy was started and the patient was qualified for renal transplantation.

Conclusion

Adolescents with an unclear picture of retinal lesions, who have neither a history nor clinical signs of a systemic disease, should undergo careful systemic screening with BP assessment. A sudden deterioration of vision may be the first symptom of a previously undiagnosed severe systemic disease (very rare chronic) that requires immediate treatment.Key Words: Hypertensive crisis, Hypertensive choroidopathy, Hypertensive retinopathy, Chronic renal failure  相似文献   
7.
Considering the increasing age of individuals affected with heart failure (HF), a specific approach to their treatment is required, with more attention paid to geriatric conditions such as poor mobility, multiple disabilities, and cognitive impairment. Frailty is a distinct biological syndrome reflecting decreased physiologic reserve and resistance to stressors. It was shown to occur frequently in patients with heart failure, with the prevalence ranging from 15 to 74 %, depending on the studied population and the method of assessment. We reviewed literature data on the influence of frailty, skeletal abnormalities, comorbidities and geriatric condition on diagnosis, treatment, and outcomes in elderly patients with HF. Identification of frailty in patients with HF is important from the clinical point of view, as this condition exerts unfavorable effects on the course of heart failure. Frailty contributes to a higher frequency of visits to emergency departments, hospitalizations, and mortality in patients with HF. Exercise may improve mobility, and nursing support can be implemented to help the patients adhere to medications. Therefore, frail patients should be diagnosed and treated according to available guidelines, and successfully educated about their condition.  相似文献   
8.
The aim of this study was to evaluate the influenza vaccination status among paediatric patients with inflammatory bowel disease (IBD) in Poland. This was a questionnaire‐based study. 242 patients with IBD and 142 controls were enrolled in the study. Of patients with IBD, 7·8% received an influenza vaccine, compared to 18·3% of controls (P = 0·0013). There were no statistically significant differences in time from IBD diagnosis, disease activity and in drugs, between vaccinated and non‐vaccinated IBD children. In conclusion, the data of our study demonstrate an alarmingly poor influenza vaccination status in the majority of children with IBD. Therefore, there is an unmet need to implement better influenza vaccination strategies for this group of patients.  相似文献   
9.
10.
The dissolution of molecular nitrogen in Ga and Fe was investigated by ab initio calculations and some complementary experiments. It was found that the N bonding inside these solvents is fundamentally different. For Ga, it is between Ga4s and Ga4p and N2p states whereas for Fe this is by N2p to Fe4s, Fe4p and Fe3d states. Accordingly, the energy of dissolution of N2 for arbitrarily chosen starting atomic configurations was 0.535 eV/mol and −0.299 eV/mol for Ga and Fe, respectively. For configurations optimized with molecular dynamics, the difference between the corresponding energy values, 1.107 eV/mol and 0.003 eV/mol, was similarly large. Full thermodynamic analysis of chemical potential was made employing entropy-derived terms in a Debye picture. The entropy-dependent terms were obtained via a normal conditions path to avoid singularity of ideal gas entropy at zero K. Nitrogen solubility as a function of temperature and N2 pressure was evaluated, being much higher for Fe than for Ga. For T=1800 K and p=104 bar, the N concentration in Ga was 3×103 at. fr. whereas for Fe, it was 9×102 at. fr. in very good agreement with experimental data. It indicates that liquid Fe could be a prospective solvent for GaN crystallization from metallic solutions.  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