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   3669篇
  免费   249篇
  国内免费   24篇
耳鼻咽喉   36篇
儿科学   93篇
妇产科学   57篇
基础医学   376篇
口腔科学   60篇
临床医学   320篇
内科学   791篇
皮肤病学   52篇
神经病学   236篇
特种医学   51篇
外科学   622篇
综合类   108篇
一般理论   2篇
预防医学   274篇
眼科学   121篇
药学   417篇
中国医学   67篇
肿瘤学   259篇
  2023年   31篇
  2022年   111篇
  2021年   167篇
  2020年   89篇
  2019年   107篇
  2018年   117篇
  2017年   74篇
  2016年   105篇
  2015年   112篇
  2014年   140篇
  2013年   183篇
  2012年   283篇
  2011年   300篇
  2010年   139篇
  2009年   118篇
  2008年   238篇
  2007年   203篇
  2006年   189篇
  2005年   202篇
  2004年   174篇
  2003年   156篇
  2002年   132篇
  2001年   68篇
  2000年   69篇
  1999年   53篇
  1998年   39篇
  1997年   22篇
  1996年   22篇
  1995年   18篇
  1994年   17篇
  1993年   11篇
  1992年   31篇
  1991年   27篇
  1990年   16篇
  1989年   22篇
  1988年   16篇
  1987年   17篇
  1986年   19篇
  1985年   15篇
  1984年   10篇
  1983年   8篇
  1982年   5篇
  1980年   6篇
  1979年   7篇
  1978年   9篇
  1977年   5篇
  1974年   6篇
  1973年   5篇
  1971年   4篇
  1966年   6篇
排序方式: 共有3942条查询结果,搜索用时 78 毫秒
61.

Objective

To assess the implementation and efficiency of medical education among the caregivers of children with congenital heart disease (CHD) and to investigate its success factors.

Material and method

A cross-sectional study was conducted from February 2014 to March 2014 in a tertiary healthcare center. Study included 120 caregivers of children with CHD visiting the Paediatric Cardiology Clinic that included 93% mothers, aged 31.72 ± 6.67 years, 38.3% Saudi citizens and 45.0% had a high educational level. Caregivers were interviewed through a semi-structured questionnaire that included socio-demographic data of participants and demographic and clinical data of patients; awareness about the diagnosis and self-assessed understanding of thedisease; disease dimensions explained, educational material used andefficacy of whole medical education received in alleviating caregivers' anxiety.

Results

Of children who had CHD, around 42.5% were males aged 5.65 ± 3.99 years and 37.3% had ventral septal defect, 14.4% had atrial septal defectand 19.5% had a complex CHD. Study results showed that 83.3% of caregivers were aware of the correct diagnosis and 64.2% had good understanding of the nature and effect of the disease. Frequently explained disease dimensions were impact on child's growth (65.8%), complications (57.5%), and outcomes (55.0%). Least frequently explained dimensions were those related to infective endocarditis (IEC) including risk factors (15.8%), prophylaxis (17.5%), complications (19.2%) and symptoms (22.5%). The whole medical education received was efficient to enable good understanding of the disease and alleviate anxiety in 70.8% and 62.5% of the cases, respectively. Time dedicated to educate, use of illustrating educational materials, explaining various disease dimensions (aetiology, complications, prognosis, long-term management, etc.) and the number of dimensions explained were all significant predictors for both good understanding of the child's disease and anxiety relief among caregivers.  相似文献   
62.
Factors associated with poor outcomes in patients with lupus nephritis   总被引:1,自引:0,他引:1  
The objective of this study was to identify the factors associated with important clinical outcomes in a case-control study of 213 patients with lupus nephritis. Included were 47% Hispanics, 44% African Americans and 9% Caucasians with a mean age of 28 years. Fifty-four (25%) patients reached the primary composite outcome of doubling serum creatinine, end-stage renal disease or death during a mean follow-up of 37 months. Thirty-four percent African Americans, 20% Hispanics and 10% Caucasians reached the primary composite outcome (P < 0.05). Patients reaching the composite outcome had predominantly proliferative lupus nephritis (WHO classes: 30% III, 32% IV, 18% V and 5% II, P < 0.025) with higher activity index score (7 +/- 6 versus 5 +/- 5, P < 0.05), chronicity index (CI) score (4 +/- 3 versus 2 +/- 2 unit, P < 0.025), higher baseline mean arterial pressure (MAP) (111 +/- 21 versus 102 +/- 14 mmHg, P < 0.025) and serum creatinine (1.9 +/- 1.3 versus 1.3 +/- 1.0 mg/dL, P < 0.025), but lower baseline hematocrit (29 +/- 6 versus 31 + 5%, P < 0.025) and complement C3 (54 +/- 26 versus 65 + 33 mg/dL, P < 0.025) compared to controls. More patients reaching the composite outcome had nephrotic range proteinuria compared to controls (74% versus 56%, P < 0.025). By multivariate analysis, CI (hazard ratio [95% CI] 1.18 [1.07-1.30] per point), MAP (HR 1.02 [1.00-1.03] per mmHg), and baseline serum creatinine (HR 1.26 [1.04-1.54] per mg/dL) were independently associated with the composite outcome. We concluded that hypertension and elevated serum creatinine at the time of the kidney biopsy as well as a high CI are associated with an increased the risk for chronic renal failure or death in patients with lupus nephritis.  相似文献   
63.
64.
65.
Digestive Diseases and Sciences - Esophageal diverticula can cause significant symptoms and affect the quality of life. There has been recent interest in the use of peroral endoscopic myotomy in...  相似文献   
66.
Accurate mapping of timber resources in commercial forestry is essential to support planning and management operations of forest growers. Over the last two decades, Light Detection and Ranging (LiDAR) systems have been successfully deployed for the collection of point-cloud data for accurate modelling of forest attributes that are traditionally obtained from plot-based inventory. In recent years, studies conducted in North America and Scandinavia have shown that three-dimensional point clouds derived from digital aerial photogrammetric (AP) data can be used to model forest attributes with a level of accuracy similar to traditional LiDAR-based approaches. A comparative analysis of the performance of the two point-cloud technologies has never been attempted in Australian plantations. In this study, we compared the performance of LiDAR-based and AP-based point clouds for estimating total recoverable volume in a Pinus radiata plantation at Springfield in north-eastern Tasmania, using volume data collected by harvesting machines as a reference. Our results showed that AP point clouds can be used for mapping total recoverable volume in P. radiata plantations with levels of accuracy that are comparable to LiDAR-based estimates. Plot-level relative root mean squared error (RMSE%) values were 23.85% for LiDAR and ranged from 22.07% to 27.10% for the three AP dense point-cloud settings evaluated. At the stand level, RMSE% decreased to 9.86% and 8.91% for LiDAR and AP, respectively. Both LiDAR-based and AP-based modelled volumes showed a close agreement with volumes measured using harvester head data, demonstrating the potential of AP technology for the management and planning of forestry operations in softwood plantations.  相似文献   
67.
Objective:Lead (Pb) is a long-known poison of environment and industrial origin. Its prolonged exposure affects cellular material and alters cellular genetics and produces oxidative damages. In this study, we investigated the exposure of chronic sustained hypoxia or lead acetate alone or in combination with or without supplementation of α-tocopherol on hepatic oxidative and nitrosative stress in rats.Results:Exposure of both lead and hypoxia showed decreased body weight, altered serum lipid profile, oxidant and enzymatic antioxidants status, serum HIF-1α and VEGF concentrations. Simultaneous α-tocopherol supplementation showed beneficial effects to all these alterations. Histopathological observations also showed hepatic degenerative changes after lead or hypoxia exposure either alone or in combination, but remarkable improvement has been noticed after α-tocopherol supplementation.Conclusion:Supplementation of α-tocopherol is beneficial to counter both lead acetate and hypoxia induced hepatic cytotoxicities possibly by reducing oxidative and nitrosative stress.KEY WORDS: α-tocopherol, hypoxia, lead acetate, nitrosative stress, oxidative stress  相似文献   
68.
Eating disorders are a group of psychiatric conditions characterised by disturbances in eating behaviour along with severe concern regarding bodyweight and shape, which appear to be on the rise in South Asian countries. These disorders are commonly observed in young individuals and are caused by a complex interaction of genetic, biological, psychological and social factors and associated with a wide range of adverse physical, psychological and social consequences. Treatment of these disorders can be quite expensive as it requires specialised care from a multidisciplinary team. Hence, prevention of eating disorders is essential; this should focus on modifiable risk factors such as the media and low self‐esteem, which contribute to body image dissatisfaction in young people and increases their risk of developing an eating disorder. This article provides recommendations for prevention of eating disorders specifically in the South Asian context.  相似文献   
69.
The OptiMAL test detects both Plasmodium falciparum and P. vivax malaria infections. In this study, we evaluated the performance of the OptiMAL test at the Basic Health Units (BHUs) and the District Health Quarter (DHQ) Center in rural villages of Punjab, Pakistan that provide minimal health services. Two sets of blood specimens obtained from 930 suspected malaria patients attending these BHUs were tested at BHUs and the DHQ Center by microscopy and the OptiMAL test. At the BHUs, 231 (25%) of the patients were positive by microscopy and 278 (30%) patients tested positive by the OptiMAL test. At the DHQ Center, microscopic analysis of a second set of specimens from the same patients confirmed the malaria infection in 386 (42%) patients and the OptiMAL test result was positive in 300 (32%) patients. To determine the performance of OptiMAL test at the BHUs and the DHQ Center, all data were compared with microscopy results obtained at the DHQ Center. The OptiMAL test results for P. falciparum at the BHUs were comparable to those of the OptiMAL test at the DHQ Center. However, the sensitivity, positive predictive value (PPV), and negative predictive value (NPV) of the OptiMAL test were considerably lower for P. vivax infections than for P. falciparum infections, irrespective of whether the test was performed at the BHUs or at the DHQ Center (P. falciparum: sensitivity = 78-85%, PPV = 89-97%, NPV = 96-98%; P. vivax: sensitivity = 61-76%, PPV = 88-95%, NPV = 90-93%). The OptiMAL test also detected a number of false-positive and false-negative results at both the BHUs and the DHQ Center. The false-positive results ranged from 1% to 2%; however, the number of false-negative results was much higher (BHUs: P. falciparum = 22%, P. vivax = 39%; DHQ Center: P. falciparum = 15%, P. vivax = 24%). In conclusion, these results, when combined with other advantages of the OptiMAL test, suggest that this test can be used by relatively inexperienced persons to diagnose malaria infection in rural areas where facilities for microscopy are not available.  相似文献   
70.
BACKGROUND & AIMS: Celiac disease and hereditary hemochromatosis are common HLA-defined conditions in northwestern Europe. We sought to determine whether there is a genetic relationship between the 2 diseases and if hemochromatosis susceptibility gene (HFE) mutations are protective against iron deficiency in celiac disease. METHODS: Polymerase chain reaction amplification using sequence-specific primers capable of identifying the 2 HFE gene mutations (H63D and C282Y) and the HLA class I and II alleles was used to type 145 white patients with celiac disease and 187 matched controls. Hemoglobin and fasting serum iron levels in celiac patients were measured at diagnosis. RESULTS: HFE gene mutations, H63D or C282Y, were identified in 70 celiac patients (48.3%) and 61 controls (32.6%) (P = 0.004). The C282Y mutation was associated with HLA-A*03 and B*07 alleles in controls and with A*01, A*03, B*08, and DRB1*0301 alleles in celiac patients; the H63D mutation was associated with HLA-A*25 and DRB1*03 alleles in controls and A*29 and DRB1*03 alleles in celiac patients. At diagnosis, celiac patients with the C282Y mutation had higher mean hemoglobin and fasting serum iron levels compared with the HFE wild type (P = 0.0002 and 0.006, respectively). This was not observed with the H63D mutation. CONCLUSIONS: In celiac disease, HFE gene mutations are common and are in linkage disequilibrium with different HLA alleles compared with controls. A disease-specific haplotype that carries C282Y and DQB1*02 is suggested. We propose that HFE gene mutations provide a survival advantage by ameliorating the iron deficiency seen in celiac patients.  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