全文获取类型
收费全文 | 4046篇 |
免费 | 225篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 236篇 |
妇产科学 | 20篇 |
基础医学 | 310篇 |
口腔科学 | 49篇 |
临床医学 | 345篇 |
内科学 | 1147篇 |
皮肤病学 | 53篇 |
神经病学 | 309篇 |
特种医学 | 133篇 |
外科学 | 679篇 |
综合类 | 84篇 |
一般理论 | 1篇 |
预防医学 | 111篇 |
眼科学 | 196篇 |
药学 | 296篇 |
中国医学 | 10篇 |
肿瘤学 | 236篇 |
出版年
2024年 | 1篇 |
2023年 | 47篇 |
2022年 | 35篇 |
2021年 | 228篇 |
2020年 | 76篇 |
2019年 | 139篇 |
2018年 | 219篇 |
2017年 | 119篇 |
2016年 | 136篇 |
2015年 | 122篇 |
2014年 | 211篇 |
2013年 | 282篇 |
2012年 | 395篇 |
2011年 | 392篇 |
2010年 | 200篇 |
2009年 | 152篇 |
2008年 | 241篇 |
2007年 | 281篇 |
2006年 | 265篇 |
2005年 | 208篇 |
2004年 | 172篇 |
2003年 | 135篇 |
2002年 | 117篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 13篇 |
1998年 | 17篇 |
1997年 | 11篇 |
1996年 | 10篇 |
1995年 | 15篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有4292条查询结果,搜索用时 46 毫秒
991.
Gupta SK Croffie JM Pfefferkorn MD Fitzgerald JF 《Digestive diseases and sciences》2003,48(3):605-607
Our objective was to examine the diagnostic yield of duodenal aspirates for Giardia in children and compare it to results of duodenal mucosal biopsies. The results of all duodenal aspirates submitted for direct parasite examinations over a 31-month period were reviewed, as were the histological results of duodenal mucosal biopsies from these patients. In all, 161 children (89 boys; age range 0.33–18 years) were included in the study. Giardia was identified in the duodenal aspirate of 5.6% (9/161) patients and on duodenal mucosal biopsies from all nine patients. In conclusion, the 5.6% diagnostic yield of duodenal aspirates for Giardia is higher than reported in a previous study of adult patients from a similar geographical region (0.7%). The detection of Giardia on duodenal mucosal biopsies from all patients with positive duodenal aspirates brings into question the utility and cost of the latter test. Duodenal aspirates for Giardia may be unnecessary if duodenal mucosal biopsies are obtained for histological examination. 相似文献
992.
Sandeep Lahoti MD Marc F. Catalano MD Joseph E. Geenen MD Michael J. Schmalz MD 《Gastrointestinal endoscopy》1998,47(6):486-491
Background: Proximal migration of a biliary or pancreatic stent is an infrequent event but its management can be technically challenging. Methods: Review of all cases of proximally migrated biliary and pancreatic stents over a 10-year period at a referral pancreatic-biliary center. Data abstracted from patient records included indication for stenting, method of presentation, success of attempt, and method used. Successful methods were determined by reviewing procedure reports. Follow-up was attempted in all patients in whom stent retrieval had failed. Results: Thirty-three proximally migrated bile duct stents, and 26 proximally migrated pancreatic duct stents were identified. Most of the patients were without symptoms. Eighty-five percent of common bile duct stents and 80% of pancreatic duct stents were successfully extracted endoscopically. Seventy-one percent (34 of 48) were retrieved with a basket or balloon. Of the stents not retrieved, two patients did not return for repeat ERCP, three patients with malignant common bile duct strictures were managed with placement of a second stent, three patients with pancreatic duct stents have remained without symptoms with no further retrieval attempts, and three patients with proximally migrated pancreatic duct stents required surgery because of pain and failure of multiple endoscopic retrieval attempts. Conclusion: Over 80% of proximally migrated bile duct and pancreatic duct stents may be extracted endoscopically. Few patients will require surgery. (Gastrointest Endosc 1998;47:486-91.) 相似文献
993.
S.V. Madhu G. Sandeep B.K. Mishra M. Aslam 《Diabetes & Metabolic Syndrome: Clinical Research & Reviews》2018,12(6):923-927
Aim
The burden of diabetes is very high in our country particularly in the urban metros. The present survey was planned to ascertain the current prevalence of diabetes and prediabetes in Delhi since the available prevalence estimates are over a decade old.Methods
The present study was conducted in urban area of east Delhi and followed a multistage random sampling design. The prevalence of known diabetes was ascertained based on self reporting and prevalence of newly detected diabetes and prediabetes was based on oral glucose tolerance test (OGTT).Results
We surveyed 470 households and included 1317 individuals. Prevalence of diabetes was 18.3% (known 10.8% and newly detected 7.5%). Prevalence of prediabetes was 21% as per WHO criteria and 39.5% as per ADA criteria. The ratio of known to unknown diabetes was 1.44:1. Every third household (35.77%) had at least one known case of diabetes. High rates of obesity and central obesity were also observed in the study population.Conclusion
The present study found a strikingly high prevalence of diabetes, prediabetes and obesity in Delhi. This calls for urgent and effective preventive measures to prevent diabetes. 相似文献994.
Fetal and Neonatal Nicotine Exposure in Wistar Rats Causes Progressive Pancreatic Mitochondrial Damage and Beta Cell Dysfunction 下载免费PDF全文
Jennifer E. Bruin Maria A. Petre Sandeep Raha Katherine M. Morrison Hertzel C. Gerstein Alison C. Holloway 《PLoS Clinical Trials》2008,3(10)
Nicotine replacement therapy (NRT) is currently recommended as a safe smoking cessation aid for pregnant women. However, fetal and neonatal nicotine exposure in rats causes mitochondrial-mediated beta cell apoptosis at weaning, and adult-onset dysglycemia, which we hypothesize is related to progressive mitochondrial dysfunction in the pancreas. Therefore in this study we examined the effect of fetal and neonatal exposure to nicotine on pancreatic mitochondrial structure and function during postnatal development. Female Wistar rats were given saline (vehicle control) or nicotine bitartrate (1 mg/kg/d) via subcutaneous injection for 2 weeks prior to mating until weaning. At 3–4, 15 and 26 weeks of age, oral glucose tolerance tests were performed, and pancreas tissue was collected for electron microscopy, enzyme activity assays and islet isolation. Following nicotine exposure mitochondrial structural abnormalities were observed beginning at 3 weeks and worsened with advancing age. Importantly the appearance of these structural defects in nicotine-exposed animals preceded the onset of glucose intolerance. Nicotine exposure also resulted in significantly reduced pancreatic respiratory chain enzyme activity, degranulation of beta cells, elevated islet oxidative stress and impaired glucose-stimulated insulin secretion compared to saline controls at 26 weeks of age. Taken together, these data suggest that maternal nicotine use during pregnancy results in postnatal mitochondrial dysfunction that may explain, in part, the dysglycemia observed in the offspring from this animal model. These results clearly indicate that further investigation into the safety of NRT use during pregnancy is warranted. 相似文献
995.
Achyut BR Srivastava A Bhattacharya S Mittal B 《Clinica chimica acta; international journal of clinical chemistry》2007,377(1-2):163-169
BACKGROUND: Type 2 diabetes mellitus (T2DM) is associated with a subclinical systemic inflammation and development of complications like nephropathy, retinopathy, neuropathy and hypertension. We studied the genetic association of bi-allelic polymorphism (-511C/T) of interleukin (IL)-1beta and 86 bp variable number tandem repeat (VNTR) polymorphism of natural receptor antagonist (IL-1RN) with T2DM and associated complications in North Indians. METHODS: We genotyped 200 patients with T2DM and 223 healthy control subjects for IL-1beta (-511C/T) by PCR-RFLP. Genotyping of IL-1RN (VNTR) polymorphism was determined by gel electrophoresis after PCR amplification. RESULTS: Interleukin-1beta (-511C/T) and IL-1RN (VNTR) polymorphisms were significantly associated with T2DM. IL-1beta -511T, IL-1RN*2 and IL-1RN*3 alleles were associated with high risk of T2DM whereas; individuals with IL-1beta -511C and IL-1RN*1 alleles were at low risk. Haplotype frequency analysis showed that T2 (IL-1beta -511T/IL-1RN*2) haplotype was associated with the high risk (p=0.000; OR=2.4, 95% CI 1.68-3.34) and C1 (IL-1beta -511C/IL-1RN*1) haplotype showed low risk (p=0.000; OR=0.38, 95% CI 0.27-0.53). Further, CT, TT genotypes of IL-1beta (-511C/T) and 1/2 genotype of IL-1RN (VNTR) were found to be associated with risk of complications particularly with nephropathy in T2DM. CONCLUSION: The IL-1beta (-511C/T) and IL-1RN (VNTR) polymorphisms are significantly associated with increased risk of T2DM as well as associated complications in North Indians. 相似文献
996.
997.
Henning Steen William P Warren Milind Desai Sandeep Gautam Shanghan Lai Scott Heath Matthias Stuber Jo?o A C Lima 《Journal of cardiovascular magnetic resonance》2004,6(4):909-916
OBJECTIVE: Surface magnetic resonance imaging (MRI) for aortic plaque assessment is limited by the trade-off between penetration depth and signal-to-noise ratio (SNR). For imaging the deep seated aorta, a combined surface and transesophageal MRI (TEMRI) technique was developed 1) to determine the individual contribution of TEMRI and surface coils to the combined signal, 2) to measure the signal improvement of a combined surface and TEMRI over surface MRI, and 3) to assess for reproducibility of plaque dimension analysis. METHODS AND RESULTS: In 24 patients six black blood proton-density/T2-weighted fast-spin echo images were obtained using three surface and one TEMRI coil for SNR measurements. Reproducibility of plaque dimensions (combined surface and TEMRI) was measured in 10 patients. TEMRI contributed 68% of the signal in the aortic arch and descending aorta, whereas the overall signal gain using the combined technique was up to 225%. Plaque volume measurements had an intraclass correlation coefficient of as high as 0.97. CONCLUSION: Plaque volume measurements for the quantification of aortic plaque size are highly reproducible for combined surface and TEMRI. The TEMRI coil contributes considerably to the aortic MR signal. The combined surface and TEMRI approach improves aortic signal significantly as compared to surface coils alone. CONDENSED ABSTRACT: Conventional MRI aortic plaque visualization is limited by the penetration depth of MRI surface coils and may lead to suboptimal image quality with insufficient reproducibility. By combining a transesophageal MRI (TEMRI) with surface MRI coils we enhanced local and overall image SNR for improved image quality and reproducibility. 相似文献
998.
Sudhakar Rao Challagundla Sandeep Shewale Calum Cree Amanda Hawkins 《Foot and Ankle Surgery》2018,24(5):423-426
Background
Operative management of ever increasing ankle fractures in the elderly need a reliable system of internal fixation. We present results of one such fixation, Fibula Rod System.Methods
Patients who underwent Fibula Rod System were included. Fracture union rate, complications, time to weight bearing and patient satisfaction using FAAM score were studied.Results
The mean age of the fifteen patients included was 74 years. Satisfactory reduction was achieved and maintained in all. All fractures united. There were no infections. Complications included lack of purchase of distal AP screw (n = 1), fracture of fibula shaft (n = 1), failure to insert syndesmotic screws through zig (n = 2), delayed secondary wound healing (n = 1) and removal of metal ware (n = 2). At a mean follow-up of 12 months (n = 10 responses), median FAAM score was 91% (Interquartile range of 62%–99%).Conclusion
Fibula Rod System providing good stability and union, is a reliable operation for ankle fractures in the elderly. 相似文献999.
Gary X. Wang Sandeep S. Hedgire Thang Q. Le Jonathan D. Sonis Brian J. Yun Michael H. Lev Ali S. Raja Anand M. Prabhakar 《The American journal of emergency medicine》2017,35(4):527-530
Background
Aortic dissection is typically evaluated with computed tomography angiography (CTA). However, the feasibility of using magnetic resonance angiography (MRA) in the ED is unclear. This study examined the indications and outcomes of MRA in suspected aortic dissection evaluation in the ED.Methods
An IRB approved review identified patients who underwent MRA in the ED for acute thoracic aortic dissection from January 2010 to June 2016. Demographics, clinical assessment, CTA contraindications, outcomes, and ED disposition were analyzed.Results
50 MRAs were ordered for suspected thoracic aortic dissection. 21 (42%) for iodinated contrast allergy, 21 (42%) for renal insufficiency, 2 (4%) due to both, 2 (4%) to spare ionizing radiation, 2 (4%) for further work-up after CTA, and 2 (4%) due to prior contrast enhanced CT within 24 h. Median ED arrival to MRA completion time was 311 min. 42 studies were fully diagnostic; 7 were limited. One patient could not tolerate the examination. 49 MRAs were completed: 2 (4%) patients had acute dissection on MRA and 47 (96%) had negative exams. 17 (35%) received gadolinium. 18 (37%) patients were discharged home from the ED with a median length of stay of 643 min. 2 (4%) were admitted for acute dissection seen on MRA and 29 (59%) for further evaluation.Conclusion
MRA has a clear role in the evaluation for acute thoracic aortic dissection in the ED in patients with contraindications to CTA, and can guide management and facilitate safe discharge to home. 相似文献1000.
Ramesh Roop Rai Anjali Mathur Dinesh Mathur Harsh P Udawat Subhash Nepalia Sandeep Nijhawan Amit Mathur 《Tropical gastroenterology》2007,28(1):19-23
BACKGROUND: Prevalence of Hepatitis B virus (HBV) and Hepatitis C virus (HCV) markers including active and occult infection has not been described in diverse cohorts among HIV-infected patients in India. Earlier studies have explained the role of HBV/HCV co-infection in cohorts of injection drug users (IDUs) but the sexual co-transmission of HBV/ HCV is not completely understood. OBJECTIVE: The objective of this study was to assess the prevalence of occult HBV & HCV infection in HIV positive sexually acquired transmission risk group. MATERIALS AND METHODS: 58 sexually acquired HIV positive patients were taken up for the study of occult HBV/HCV co-infection. Data on demographics, sexual behaviour, sexually transmitted diseases (STD), medical history, laboratory tests viz., serum ALT and CD4 count were recorded. HBV serology included HBsAg, anti HBs, IgG anti HBc and HBV DNA (PCR). HCV serology included anti HCV & HCV RNA (RT-PCR). RESULTS: Occult HBV infection (HBV DNA) was observed in 12.2% (7/58 with HBsAg -ve and IgG anti HBc +ve subjects) while an overall prevalence of HBV DNA was 13.7% (12% occult & 1.7% in HBsAg+ve patients). Out of 58 HIV positive patients 29.3% demonstrated reactivity for any marker of past or current HBV infection. (HBsAg 1.7%, anti HBs 10.3% anti HBc IgG 17.2%). 4/58 (6.8%) revealed anti HCV positivity along with HCV RNA positivity by RT-PCR while 6/58 (10.3%) individuals revealed an occult HCV infection (anti HCV negative). The overall HCV RNA prevalence was 17.2%. 2 out of 58 (3.4%) individuals were positive for occult infection of both HBV DNA & HCV RNA (Triple infection HIV/HBV/ HCV). The HBV/HCV co-infected group (n = 18) showed a significantly high ALT (114.3 + 12.3 U/I) & low CD4 count (202.5 + 33.7 cells/mm3). The percent prevalence of HBV/ HCV co-infection was higher in the illiterate group, in men less than 30 years of age, and in those who were married and exhibited polygamous activity. CONCLUSIONS: The study demonstrated that in HIV infected patients testing only serological viral markers like HBsAg, antiHBcIgG & anti HCV, fails to identify the true prevalence of co-infection with HBV & HCV. Qualitative PCR for HBV DNA & HCV RNA detects co-infection in patients who are negative for serological markers. Also, in subjects who had only a sexual risk factor for parenterally transmitted infections, HIV may enhance the sexual transmission of HBV and HCV. 相似文献