全文获取类型
收费全文 | 3060篇 |
免费 | 166篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 115篇 |
妇产科学 | 49篇 |
基础医学 | 343篇 |
口腔科学 | 55篇 |
临床医学 | 189篇 |
内科学 | 500篇 |
皮肤病学 | 41篇 |
神经病学 | 215篇 |
特种医学 | 150篇 |
外科学 | 367篇 |
综合类 | 144篇 |
预防医学 | 203篇 |
眼科学 | 239篇 |
药学 | 335篇 |
中国医学 | 12篇 |
肿瘤学 | 233篇 |
出版年
2023年 | 16篇 |
2022年 | 50篇 |
2021年 | 65篇 |
2020年 | 27篇 |
2019年 | 54篇 |
2018年 | 57篇 |
2017年 | 42篇 |
2016年 | 60篇 |
2015年 | 64篇 |
2014年 | 80篇 |
2013年 | 115篇 |
2012年 | 199篇 |
2011年 | 185篇 |
2010年 | 111篇 |
2009年 | 102篇 |
2008年 | 133篇 |
2007年 | 156篇 |
2006年 | 138篇 |
2005年 | 123篇 |
2004年 | 124篇 |
2003年 | 103篇 |
2002年 | 90篇 |
2001年 | 66篇 |
2000年 | 75篇 |
1999年 | 92篇 |
1998年 | 53篇 |
1997年 | 33篇 |
1996年 | 36篇 |
1995年 | 22篇 |
1994年 | 24篇 |
1993年 | 25篇 |
1992年 | 67篇 |
1991年 | 59篇 |
1990年 | 57篇 |
1989年 | 64篇 |
1988年 | 30篇 |
1987年 | 38篇 |
1986年 | 38篇 |
1985年 | 35篇 |
1984年 | 32篇 |
1983年 | 33篇 |
1981年 | 15篇 |
1980年 | 18篇 |
1979年 | 22篇 |
1978年 | 20篇 |
1976年 | 15篇 |
1974年 | 17篇 |
1973年 | 35篇 |
1971年 | 15篇 |
1970年 | 18篇 |
排序方式: 共有3235条查询结果,搜索用时 15 毫秒
991.
Kaushik Murali Viswesh Krishna Vrishab Krishna B Kumari Sowmya Raveendra Murthy C Vidhya Payal Shah 《Indian journal of ophthalmology》2021,69(8):2045
Purpose:Amblyopia is a significant public health problem. Photoscreeners have been shown to have significant potential for screening; however, most are limited by cost and display low accuracy. The purpose of this study was validate a novel artificial intelligence (AI) and machine learning–based facial photoscreener “Kanna,” and to determine its effectiveness in detecting amblyopia risk factors.Methods:A prospective study that included 654 patients aged below 18 years was conducted in our outpatient clinic. Using an android smartphone, three images of each the participants’ face were captured by trained optometrists in dark and ambient light conditions and uploaded onto Kanna. Deep learning was used to create an amblyopia risk score based on our previous study. The algorithm generates a risk dashboard consisting of six values: five normalized risk scores for ptosis, strabismus, hyperopia, myopia and media opacities; and one binary value denoting if a child is “at-risk” or “not at-risk.” The presence of amblyopia risk factors (ARF) as determined on the ophthalmic examination was compared with the Kanna photoscreener.Results:Correlated patient data for 654 participants were analyzed. The mean age of the study population was 7.87 years. The algorithm had an F-score, 85.9%; accuracy, 90.8%; sensitivity, 83.6%; specificity, 94.5%; positive predictive value, 88.4%; and negative predictive value, 91.9% in identifying amblyopia risk factors. The P value for the amblyopia risk calculation was 8.5 × 10−142 implying strong statistical significance.Conclusion:The Kanna photo-based screener that uses deep learning to analyze photographs is an effective alternative for screening children for amblyopia risk factors. 相似文献
992.
993.
994.
995.
The indigenously produced pure titanium dental implants are economical and useful for common human use in India. The aim of this study is to test the biocompatibility of the indigenously produced pure titanium dental implant material obtained from the Defense Metallurgical Research Laboratory, Hyderabad, India, and the Institute of Nuclear Medicine and Allied Science, Delhi, India. An experimental study in rabbits was done to study the amount of ordered bone formation around the screw and cylinder type of indigenously produced pure titanium metal implant specimens. The experimental animals were killed at 4, 6, 8, 12, and 16 weeks from the date of implantation. The histopathological examination of the animals killed at 16 weeks demonstrates the presence of osteoblastic cell proliferation and early ordered bone formation toward the implant site, indicating signs of osseointegration of both screw- and cylinder-type indigenously produced pure titanium specimens. 相似文献
996.
Budrukkar A Muttagi S Shahid T Chatturvedi P Banavali S Laskar SG Murthy V D'Cruz A Agarwal JP 《The British journal of oral & maxillofacial surgery》2012,50(6):504-507
Patients with chronic myeloid leukaemia (CML) are at considerable risk of developing second primary neoplasms. However, mucosal squamous cell cancers (SCCs) of the head and neck have not been reported. We review the data of 7 patients with mucosal SCC of the head and neck that presented as metachronous second primary tumours in patients with CML. All 7 patients were men (median age 48 years, range 31-67) (site:oral cavity n=6, hypopharynx n=1). The median interval between diagnosis of CML and head neck cancer was 6 years (range 2-15). Treatment was curative in 4 and palliative in 3. At median follow up of 14 months (range 2-44), 3 patients had died of head and neck cancer, 1 of CML, and 3 were alive and free of disease. Mucosal cancers of the head and neck can occur in long-term survivors of CML. They are aggressive and tend to recur. 相似文献
997.
Vogel KJ Murthy VS Dudley B Grubs RE Gettig E Ford A Thomas SB 《Health promotion practice》2007,8(4):350-357
African Americans continue to suffer from health disparities. The Center for Minority Health (CMH) within the University of Pittsburgh has the mission to eliminate racial and ethnic health disparities. CMH has designed and implemented the Family Health History (FHH) Initiative. The FHH Initiative places genetic-counseling graduate students in the African American community to provide risk assessments and emphasize the importance of family history as it pertains to disease prevention. The FHH Initiative also allows participants to enroll into the Minority Research Recruitment Database (MRRD). This enables CMH to alert individuals to available research participation opportunities. In the first year of this program, 225 African Americans completed their family health histories. More than 60% of individuals enrolled in the MRRD. The authors report their initial successes and challenges of an initiative that incorporates awareness of family history information, proper screening guidelines, behavior-modification recommendations, and support for participation in clinical research. 相似文献
998.
ABSTRACT: We describe a system for the automated diagnosis of diabetic retinopathy and glaucoma using fundus and optical coherence tomography (OCT) images. Automatic screening will help the doctors to quickly identify the condition of the patient in a more accurate way. The macular abnormalities caused due to diabetic retinopathy can be detected by applying morphological operations, filters and thresholds on the fundus images of the patient. Early detection of glaucoma is done by estimating the Retinal Nerve Fiber Layer (RNFL) thickness from the OCT images of the patient. The RNFL thickness estimation involves the use of active contours based deformable snake algorithm for segmentation of the anterior and posterior boundaries of the retinal nerve fiber layer. The algorithm was tested on a set of 89 fundus images of which 85 were found to have at least mild retinopathy and OCT images of 31 patients out of which 13 were found to be glaucomatous. The accuracy for optical disk detection is found to be 97.75%. The proposed system therefore is accurate, reliable and robust and can be realized. 相似文献
999.
Golley RK Smithers LG Mittinty MN Brazionis L Emmett P Northstone K Campbell K McNaughton SA Lynch JW 《The Journal of nutrition》2012,142(5):901-908
The complementary feeding period is an important stage of child development. The study aim was to develop an index reflecting the degree of adherence to complementary feeding guidelines, evaluate its convergent validity, and explore associations with socio-demographic factors and dietary pattern scores in childhood. Data were analyzed from the Avon Longitudinal Study of Parents and Children (n = 6065) using parent-completed dietary questionnaires at 6 mo of age, socio-demographic information, and dietary patterns derived by principal component analysis at age 3 y. The Complementary Feeding Utility Index (CFUI) consists of 14 components: breastfeeding duration, feeding to appetite, timing of introduction to solids, exposure to iron-rich cereals, fruit and vegetable intake, exposure to high-fat/-salt/-sugar foods including sugary drinks, food texture, and meal/snack frequency. Regression analyses were undertaken to investigate associations between index scores, socio-demographic factors, food and nutrient intakes, and dietary pattern scores at age 3 y. Milk and food intake at 6 mo and nutrient intake at 8 mo of age varied across quintiles of index score in largely the expected directions. Associations were found among index score, maternal age, education, social class, maternal smoking history, and prepregnancy BMI. After adjustment for socio-demographic factors, the index score was associated with "processed" [β = -0.234 (95% CI = -0.260, -0.209)] and "healthy" [β = 0.185 (95% CI = 0.155, 0.215)] dietary pattern scores at age 3 y. The CFUI is able to discriminate across food intake, nutrient intake, and socio-demographic factors and is associated with later dietary patterns. 相似文献
1000.
Jain A Rana SS Chakravarty P Gupta RK Murthy NS Nath MC Gururaja S Chaturvedi N Verma U Kar P 《European journal of epidemiology》2003,18(7):695-698
Infection with hepatitis C virus (HCV) is a major cause of transfusion-associated hepatitis, cirrhosis and hepatocellular carcinoma. The present study was conducted with an objective to evaluate the prevalence of anti-HCV antibody in New Delhi, India using a large number of healthy voluntary blood donors. A total of 15,898 healthy voluntary blood donors were subjected to anti-HCV testing (using a commercially available third generation anti-HCV ELISA kit) and 249 were found to be reactive for anti-HCV antibody, yielding an overall prevalence of 1.57%. No significant difference was found between the HCV positivity rate of male (1.57%; 238/15,152) vs. female (1.47%; 11/746) donors, family (1.58%; 213/13,521) vs. altruistic (1.51%; 36/2377) donors and first-time (1.55%; 180/11,605) vs. repeat (1.61%; 69/4293) donors. The age distribution of anti-HCV reactivity showed a maximum prevalence rate of 1.8% in the age group of 20–29 years. In addition, there was a clear trend of decreasing positivity for anti-HCV with increasing age and this trend was statistically significant. The results of the present study show that the prevalence of anti-HCV antibodies in the healthy voluntary blood donors of New Delhi, India is considerably higher than the reported seroprevalence of HCV in majority of the industrialized nations and this represents a large reservoir of infection capable of inflicting significant disease burden on the society. In addition, donors of New Delhi, India showed a trend of decreasing seroprevalence with increasing age, possibly implying a higher exposure rate to HCV in younger subjects. 相似文献