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   1894篇
  免费   171篇
  国内免费   23篇
耳鼻咽喉   8篇
儿科学   115篇
妇产科学   82篇
基础医学   155篇
口腔科学   29篇
临床医学   439篇
内科学   350篇
皮肤病学   30篇
神经病学   115篇
特种医学   118篇
外科学   134篇
综合类   51篇
预防医学   169篇
眼科学   35篇
药学   74篇
中国医学   1篇
肿瘤学   183篇
  2023年   9篇
  2022年   13篇
  2021年   20篇
  2020年   39篇
  2019年   44篇
  2018年   49篇
  2017年   25篇
  2016年   42篇
  2015年   43篇
  2014年   48篇
  2013年   66篇
  2012年   122篇
  2011年   104篇
  2010年   77篇
  2009年   65篇
  2008年   86篇
  2007年   118篇
  2006年   87篇
  2005年   104篇
  2004年   65篇
  2003年   75篇
  2002年   65篇
  2001年   40篇
  2000年   56篇
  1999年   49篇
  1998年   36篇
  1997年   36篇
  1996年   38篇
  1995年   33篇
  1994年   26篇
  1993年   20篇
  1992年   29篇
  1991年   25篇
  1990年   33篇
  1989年   42篇
  1988年   36篇
  1987年   32篇
  1986年   24篇
  1985年   18篇
  1984年   16篇
  1983年   19篇
  1982年   16篇
  1981年   12篇
  1980年   15篇
  1979年   15篇
  1978年   8篇
  1977年   6篇
  1976年   6篇
  1975年   8篇
  1974年   6篇
排序方式: 共有2088条查询结果,搜索用时 15 毫秒
1.
2.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
3.
Pediatric prehospital care in urban and rural areas   总被引:5,自引:0,他引:5  
There are limited data concerning pediatric prehospital care, although pediatric prehospital calls constitute 10% of emergency medical services activity. Data from 10,493 prehospital care reports in 11 counties of California (four emergency medical services systems in rural and urban areas) were collected and analyzed. Comparison of urban and rural data found few significant differences in parameters analyzed. Use of the emergency medical services system by pediatric patients increased with age, but 12.5% of all calls were for children younger than 2 years. Calls for medical problems were most common for patients younger than 5 years of age; trauma was a more common complaint in rural areas (64%, P = .0001). Frequency of vital sign assessment differed by region, as did hospital contact (P less than .0001). Complete assessment of young pediatric patients, with a full set of vital signs and neurologic assessment, was rarely performed. Advanced life support providers were often on the scene, but advanced life support treatments and procedures were infrequently used. This study suggests the need for additional data on which to base emergency medical services system design and some directions for education of prehospital care providers.  相似文献   
4.
Screening for early ovarian cancer   总被引:5,自引:0,他引:5  
Taylor  KJ; Schwartz  PE 《Radiology》1994,192(1):1
  相似文献   
5.
We examined distribution characteristics of the body mass index (BMI; weight/height; kg/m2) in a sample of 1128 male and 1372 female Pima Indians aged 15-65 years. We found that women had a higher mean and variance of BMI than men. From commingling analyses, we determined that the distribution of BMI could be accounted for either by a single skewed distribution or by a mixture of multiple normal components. These component distributions may be used to define provisional thresholds in selecting families for genetic studies. To ensure genetic segregation of obesity predisposing genes in Pima families will require that some members have BMIs > or = 40 kg/m2.  相似文献   
6.
The authors report the clinical and laboratory findings of a patient who had severe immune hemolytic anemia due to hydrochlorothiazide (HCTZ). In this case, the HCTZ antibody reacted not only with other thiazide and thiazide-like drugs, but also with a chemically unrelated diuretic, ethacrynic acid. These results indicate that HCTZ antibody activity is not restricted solely to the thiazides and imply that therapy with any of the reactive drugs would be contraindicated for this patient. The serologic screening for drug reactivity may be useful for selecting alternative therapy for patients with drug-induced immune hemolytic anemia.  相似文献   
7.
8.
PURPOSE: Fibreoptic intubation (FOI) has become an essential technique in the anesthetic management of patients with difficult airways. Unfortunately, residents may graduate from anesthesiology training programs with insufficient skills in FOI. To enhance resident proficiency at FOI without compromising patient comfort or safety, the technique of transnasal jet ventilation-assisted FOI was developed. This report describes our initial experience with this technique. METHODS: Sixty-four patients scheduled for oromaxillofacial surgery under nasal endotracheal anesthesia were recruited. Twenty-eight residents at all levels of training performed FOI through the patient's right nostril after the induction of general anesthesia and neuromuscular blockade. Oxygenation and ventilation were maintained by a faculty anesthesiologist using a Sanders device to deliver a jet of oxygen through a nasal trumpet placed in the patient's left nostril. The time from induction until completion of the FOI was recorded. Residents were subsequently queried about the educational benefit of the technique using a standardized questionnaire. RESULTS: All residents were able to successfully intubate all patients in this study. Thirteen residents successfully performed intubations on three or more occasions with 70% performing the technique faster on the third trial than on the first. No evidence of hypoxemia, gastric distension, pneumothorax, hemodynamic instability or recall was observed. All respondents to the questionnaire reported that the technique was useful as an educational tool and recommended its use with other residents. CONCLUSION: Transnasal jet ventilation-assisted FOI is a useful method to train residents in FOI while maximizing patient comfort and safety.  相似文献   
9.
OBJECTIVE: This paper describes evidence of a positive effect of both endogenous and exogenous estrogen and progesterone on lung function across the life span in women. DATA SOURCES: Articles were identified using the keywords asthma, pulmonary function, menarche, menopause, estrogen, progesterone, hormone replacement therapy, oral contraceptives, and menstrual cycle from years 1966 to 2001 in MEDLINE. Additional studies were identified from article reference lists. STUDY SELECTION: Relevant, peer-reviewed original research articles in the English language were selected. RESULTS: Estrogen and/or progesterone may alter pulmonary function and asthma. Premenopausal women experience decreases in pulmonary function and increases in asthma exacerbations and hospitalizations during the premenstrual and menstrual phases. Oral contraceptives and hormone replacement therapy are associated with improved pulmonary function and decrease in asthma exacerbation. Some asthmatic patients experience improved pulmonary function and reduced asthma medication requirement during pregnancy. CONCLUSIONS: Estrogen and progesterone modify airway responsiveness. Further research is needed to elucidate the clinical relevance of estrogen and progesterone in the pathophysiology and therapy of asthma.  相似文献   
10.
Tumor vascular signals in renal masses: detection with Doppler US   总被引:3,自引:0,他引:3  
Ramos  IM; Taylor  KJ; Kier  R; Burns  PN; Snower  DP; Carter  D 《Radiology》1988,168(3):633-637
The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses.  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