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   42737篇
  免费   2648篇
  国内免费   435篇
耳鼻咽喉   518篇
儿科学   1343篇
妇产科学   1096篇
基础医学   4251篇
口腔科学   1343篇
临床医学   3876篇
内科学   9019篇
皮肤病学   784篇
神经病学   2406篇
特种医学   1483篇
外国民族医学   4篇
外科学   7578篇
综合类   1617篇
现状与发展   3篇
一般理论   28篇
预防医学   2844篇
眼科学   1509篇
药学   3416篇
  3篇
中国医学   579篇
肿瘤学   2120篇
  2024年   78篇
  2023年   517篇
  2022年   1290篇
  2021年   1959篇
  2020年   1210篇
  2019年   1436篇
  2018年   1767篇
  2017年   1360篇
  2016年   1429篇
  2015年   1592篇
  2014年   1999篇
  2013年   2398篇
  2012年   3566篇
  2011年   3413篇
  2010年   1998篇
  2009年   1742篇
  2008年   2582篇
  2007年   2623篇
  2006年   2304篇
  2005年   2049篇
  2004年   1825篇
  2003年   1579篇
  2002年   1344篇
  2001年   463篇
  2000年   390篇
  1999年   335篇
  1998年   220篇
  1997年   156篇
  1996年   157篇
  1995年   124篇
  1994年   115篇
  1993年   92篇
  1992年   151篇
  1991年   170篇
  1990年   135篇
  1989年   127篇
  1988年   109篇
  1987年   104篇
  1986年   89篇
  1985年   122篇
  1984年   79篇
  1983年   54篇
  1982年   57篇
  1981年   55篇
  1980年   41篇
  1979年   51篇
  1978年   40篇
  1975年   35篇
  1974年   38篇
  1973年   37篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
BACKGROUND: Over 50% of patients with chronic heart failure (CHF) have sleep-disordered breathing (SDB). Any variation in the type of SDB in CHF will have implications for patient management. Currently there is good evidence for treatment of obstructive sleep apnea (OSA) in CHF with continuous positive airway pressure; however, for central sleep apnea (CSA) the treatment is less clear. AIMS: The aim of this study was to investigate the variation in the severity and type of SDB (OSA vs. CSA) throughout 4 consecutive nights in CHF patients with SDB. METHODS: Nineteen male CHF patients (mean+/-sd: age 61+/-9 years; left ventricular ejection fraction: 34+/-10% and percent predicted peak VO2: 67+/-19%) underwent cardiorespiratory monitoring in their own home throughout 4 consecutive nights. RESULTS: There was minimal variation in apnea-hypopnea index (AHI) throughout 4 nights in CHF patients with SDB [intraclass correlation coefficient (95% confidence interval (CI)): 0.97 (95% CI 0.76 and 0.97)]. Eight patients [42% (95% CI 20% and 64%)] demonstrated a shift in the type of their SDB, from CSA to OSA or vice versa; these patients had significantly smaller neck circumference (group mean+/-sd) 42+/-2 vs. 44+/-2 cm; p=0.04), and had significant variation in the central AHI [intraclass correlation coefficient: 0.51 (95% CI 0.16 and 0.85)]. CONCLUSIONS: A single night of cardiorespiratory monitoring is representative of moderate-to-severe SDB in patients with CHF. However, a high proportion of patients shift their type of SDB over 4 nights. These findings may have implications for the management of SDB in CHF.  相似文献   
912.

Background:

Pediatric neck mass is a frequent cause for surgical consultation. Neck masses can be simply classified into congenital, inflammatory, and neoplastic. Although most of the cases are due to benign processes, malignant causes must not be overlooked. The aim of this study is to assess the paediatric neck masses in Iraqi patients highlighting the distribution of cases according to their demographic characteristics and etiology.

Patients and Methods:

A cross-sectional observed study is conducted in the Department of Pediatric Surgery, at the Central Teaching Hospital of Pediatrics in Baghdad from April 2008 to March 2009. Sixty four patients with neck masses aged 14 years and below were examined and managed. The underlying causes of the neck masses were addressed and categorized.

Results:

Among the 64 patients, 42 (65.6%) were male. The inflammatory group represents 57% of the cases, while the malignant neoplasm accounts for approximately 10% of the conditions mainly due to lymphoma 5 (7.8%). Sixteen patients (25%) fall in the congenital group, in which the thyroglossal duct cyst was the commonest type. Wound infection developed in two patients, while one patient with cystic hygroma showed recurrence.

Conclusion:

Pediatrics neck masses are distributed in categories that similar in pattern and distribution in the world except the infectious/inflammatory category that shows variation in distribution in respect to the socioeconomic status. The surgical intervention and procedures are related to the facility as well as to the experience.Key words: Inflammatory, neoplastic, pediatrics neck masses, reactive lymphadenitis  相似文献   
913.
Visceral basidiobolomycosis is an unusual fungal infection of viscera caused by saprophyte Basidiobolus ranarum. It is very rare in healthy children and poses a diagnostic challenge due to the non-specific clinical presentation and the absence of predisposing factors. We report a case of gastrointestinal basidiobolomycosis in a 4-year-old healthy girl who presented with a short history of abdominal pain, bleeding per rectum, fever, and weight loss. The diagnosis was based on high eosinophilic count, classical histopathology findings of fungal hyphae (the Splendore-Hoeppli phenomenon), and positive fungal culture from a tissue biopsy. Fungal infection was successfully eradicated with a combined approach of surgical resection of the infected tissue and a well-monitored course of antifungal therapy. The atypical clinical presentation, diagnostic techniques, and the role of surgery in the management of a rare and lethal fungal disease in an immunocompetent child are discussed.Key words: Basidiobolomycosis, child, fungal infection, gastrointestinal, immunocompetent  相似文献   
914.
OBJECTIVE: To determine the frequency and clinical characteristics of osteoarticular complications of brucellosis in an endemic region in Iran. METHODS: In a prospective study we evaluated 245 patients with brucellosis diagnosed between January 2004 and December 2005. Patients included were those older than 8 years of age and who had clinical features suggestive of brucellosis and specific antibodies at significant titers, and/or positive blood or body fluid culture for Brucella species. A bone scan was performed in those with a clinical suspicion of osteoarticular involvement. RESULTS: Seventy patients (28.6%) had osteoarticular complications. Sacroiliitis was the most common complication (75.7%), followed by spondylitis (21.4%) and peripheral arthritis (8.6%). Spondylitis was the most common osteoarticular complication in the elderly. Relapses occurred in five (2%) patients, three of them with spondylitis. CONCLUSIONS: Osteoarticular disease is the most common complication of brucellosis in Western Iran. Sacroiliitis is the most common form of osteoarticular complication. With the use of a proper treatment regimen, the prospect for recovery is good.  相似文献   
915.
BM remains an important source of stem cells. The BM characteristics change with age but the estimation of CD34 calculation of one CD34+ cell per 100 nucleated cells is used for all donors including pediatric donors in the operating room before getting the actual CD34 count. In order to see whether this formula is applicable for pediatric donors, we designed a retrospective study to see the affect of the age and sex on the BM NCC, CD34 count, and CD34/NCC ratios. Ninety‐eight BM collections from 91 related donors were evaluated retrospectively (median age: nine yr [1.5–54 yr]; M/F: 41/50). A significant negative correlation was found between the donor age and NCC (r = −0.229, p < 0.05), CD34 count (r = −0.563, p < 0.01), and CD34/NCC (r = −0.664, p < 0.01). The negative correlation for CD34 count and CD34/NCC persisted in female and male donor groups. When donors younger than 16 yr of age were compared with the older donor group, the median NCC, median CD34 count, and CD34/NCC were significantly lower in the older group (p < 0.01). Age and sex have to be taken into consideration to avoid unnecessary high‐volume collections and increased operating room time in the younger donors.  相似文献   
916.
Communicating with patients with inflammatory bowel disease   总被引:6,自引:0,他引:6  
Husain A  Triadafilopoulos G 《Inflammatory bowel diseases》2004,10(4):444-50; discussion 451
Ulcerative colitis and Crohn's disease, the two main forms of inflammatory bowel disease (IBD), are chronic illnesses that affect hundreds of thousands of Americans. Patients with IBD suffer chronically from diarrhea, abdominal pain, gastrointestinal bleeding, malabsorption, and weight loss requiring continuous medical and surgical attention. Despite recent advances in therapy, IBD follows a course of exacerbations and remissions with approximately 25-50% of patients relapsing annually. Hence, these diseases are readily encountered in primary care and gastroenterology clinics. Though medical and surgical treatment options have improved significantly, little has been written about the psychosocial aspects of IBD. Currently, there is a paucity of data concerning effective communication methods enabling physicians to develop stronger rapport with patients suffering from IBD, the care of whom requires a multidisciplinary approach involving primary care physicians, gastroenterologists, and colorectal surgeons. Because IBD has a high morbidity, it is worthwhile to further investigate those social factors that will improve patients' quality of life. In this paper, we summarize some of the common problems that emerge when taking care of patients with IBD and provide initial guidelines based on the world literature regarding the management and education of patients with IBD. Both primary care physicians and specialists (gastroenterologists, colorectal surgeons) need to be aware of the questions and concerns of IBD patients and to be capable of dispensing the information in a clear and concise manner. Using the case scenario format, we review the most common aspects of communication for health care professionals taking care of IBD patients and suggest ways to establish and maintain long-term doctor-patient relationships. The two most significant interventions that dramatically improve quality of life and patient-physician relationships are proper patient education and appropriate treatment of concurrent depression and anxiety. We hope that our review will form a framework by which different members of the medical team learn their roles in the complex management decisions affecting IBD patients.  相似文献   
917.
Pulmonary involvement in Beh?et's disease is an uncommon condition (12%). Thromboembolism of the superior vena cava and/or other mediastinal veins, aneurysms of the aorta and pulmonary arteries are the main vascular manifestations in addition to pulmonary infarct and intrathoracic hemorrhage. Despite their scarcity, respiratory symptoms may be life-threatening. The aim of this study was to assess the contribution of thoracic imaging for one of the most serious aspects of the disease: pulmonary artery aneurysm. We report five patients with pulmonary artery aneurysms (mean age: 39.5 years). Hemoptysia revealed Beh?et's disease in three. Initially explored by conventional radiography, computed tomography and angiography, pulmonary artery aneurysms are currently investigated well with helicoidal computed tomography, digital angiography, magnetic resonance imaging (MRI) and angio-MRI. These imaging techniques provide helpful information for the diagnosis of Beh?et's disease.  相似文献   
918.
Approximately, one fourth of women have leiomyomas. Leiomyomas are benign tumors that originated from smooth muscle cells. Estrogen is claimed to relate as a cause but exact mechanism has not fully understood. In this study, 95 leiomyoma cases that have been diagnosed by our department in years between 2010 and 2012 were examined. Age ranges of patients, sizes, locations, and numbers of leiomyomas were identified. Immunohistochemically ER (estrogen), PR (progesterone), and Gross cystic disease fluid protein-15 stains were performed to the paraffin blocks and their percentages of staining were noted. Statistically, submucosal and intramural locations were significantly related to ER and PR (p < 0,001). There were significant relationship between ER and PR in 30–50 years age group (p < 0,001). There were significant relationship between ER, PR and locations (p < 0,001), numbers (p < 0,001), sizes of leiomyomas (below 5 cm; p < 0,001), (between 5 and 10 cm; p = 0,037), larger than 10 cm; p = 0,002). Consequently, relationship between leiomyoma and ER, PR were revealed in this study. Also, relationship between leiomyoma locations and patient ages were identified statistically. There was no immunoreactivity with GCDFP-15 in leiomyomas.  相似文献   
919.
AIM: The healthy ranges for serum alanine aminotransferase (ALT) levels are less well studied. The aim of this study was to define the upper limit of normal (ULN) for serum ALT levels, and to assess factors associated with serum ALT activity in apparently healthy blood donors. METHODS: A total of 1,939 blood donors were included. ALT measurements were performed for all cases using the same laboratory method. Healthy ranges for ALT levels were computed from the population at the lowest risk for liver disease. Univariate and multivariate analyses were performed to evaluate associations between clinical factors and ALT levels. RESULTS: Serum ALT activity was independently associated with body mass index (BMI) and male gender, but not associated with age. Association of ALT with BMI was more prominent in males than in females. Upper limit of normal for non-overweight women (BMI of less than 25) was 34 U/L, and for non-overweight men was 40 U/L. CONCLUSION: Serum ALT is strongly associated with sex and BMI. The normal range of ALT should be defined for male and female separately.  相似文献   
920.
AIM:The healthy ranges for serum alanine aminotransferase (ALT) levels are less well studied. The aim of this study was to define the upper limit of normal (ULN) for serum ALT levels, and to assess factors associated with serum ALT activity in apparently healthy blood donors.METHODS: A total of 1 939 blood donors were included.ALT measurements were performed for all cases using the same laboratory method. Healthy ranges for ALT levels were computed from the population at the lowest risk for liver disease. Univariate and multivariate analyses were performed to evaluate associations between clinical factors and ALT levels.RESULTS: Serum ALT activity was independently associated with body mass index (BMI) and male gender, but not associated with age. Association of ALT with BMI was more prominent in males than in females. Upper limit of normal for non-overweight women (BMI of less than 25) was 34 U/L,and for non-overweight men was 40 U/L.CONCLUSION: Serum ALT is strongly associated with sex and BMI. The normal range of ALT should be defined for male and female separately.  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