全文获取类型
收费全文 | 1913篇 |
免费 | 87篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 60篇 |
妇产科学 | 124篇 |
基础医学 | 179篇 |
口腔科学 | 74篇 |
临床医学 | 186篇 |
内科学 | 359篇 |
皮肤病学 | 64篇 |
神经病学 | 115篇 |
特种医学 | 134篇 |
外科学 | 313篇 |
综合类 | 31篇 |
预防医学 | 55篇 |
眼科学 | 62篇 |
药学 | 101篇 |
中国医学 | 3篇 |
肿瘤学 | 116篇 |
出版年
2023年 | 9篇 |
2022年 | 30篇 |
2021年 | 51篇 |
2020年 | 39篇 |
2019年 | 50篇 |
2018年 | 54篇 |
2017年 | 35篇 |
2016年 | 67篇 |
2015年 | 51篇 |
2014年 | 86篇 |
2013年 | 104篇 |
2012年 | 160篇 |
2011年 | 160篇 |
2010年 | 98篇 |
2009年 | 78篇 |
2008年 | 138篇 |
2007年 | 136篇 |
2006年 | 129篇 |
2005年 | 137篇 |
2004年 | 112篇 |
2003年 | 72篇 |
2002年 | 58篇 |
2001年 | 25篇 |
2000年 | 18篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 15篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 21篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 5篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1940年 | 1篇 |
1938年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有2024条查询结果,搜索用时 15 毫秒
1.
2.
3.
Ayhan Ozturk C Elif Ozturk Burcu Ozdemirli Muhterem Yucel Talat Bah?eba?i 《Seizure》2007,16(2):147-152
It is well known that there might be an epidemiological association between Helicobacter pylori infection and extraintestinal diseases. This study aimed at determining H. pylori infection in epileptic patients. Forty-seven cryptogenic epileptic patients (Group 1) and 35 healthy people (Group 2) participated in this study. Presence of H. pylori infection was examined by H. pylori stool antigen (HpSA), H. pylori IgG, and IgM. HpSA was detected in 21 participants (44.6%) in Group 1 and in 3 participants (8.5%) in Group 2. H. pylori IgM was positive in 27 participants (57.4%) in Group 1 and in 8 participants (22.8%) in Group 2. H. pylori IgG was positive in 37 participants (78.7%) in Group 1 and in 13 participants (38%) in Group 2. The difference of rates of HpSA, H. pylori IgM and IgG in Groups 1 and 2 were found statistically significant (chi2=4.18, p=0.04; chi2=9.18, p=0.0017; chi2=14.58, p<0.001, respectively). We also compared presence of H. pylori infection between the epileptic patients with poor and good prognosis; HpSA positivity was detected in 15 (62.5%) of 24 and 6 (26%) of 23, respectively, and the differences were statistically significant (chi2=6.30, p=0.012). H. pylori IgM positivity was detected in 16 (66%) of 24 patients with poor prognosis and 11 (47.8%) of 23 patients with good prognosis (p>0.05). H. pylori IgG positivity was detected in 18 (75%) of 24 patients with poor prognosis and 19 (82.6%) of 23 patients with good prognosis. The differences of H. pylori IgM and IgG positivity rates in epileptic patients with poor and good prognosis were not found statistically significant (p>0.05). These results suggest a probable association between the acute H. pylori infection and epilepsy, especially with poor prognosis. 相似文献
4.
5.
Inferior vena cava filters were placed in 60 patients. Ultrasound (US) of the venous access site was performed before and 3-5 days after filter placement to determine the prevalence of occlusive and nonocclusive access-site thrombosis (AST). Prevalence of symptoms attributable to AST was also evaluated at 1-month clinical follow-up in 58 of the 60 patients. All filters were placed with delivery sheaths with outer diameters of 12-14 F. US depicted development of occlusive AST in six of the 60 patients (10%). Nonocclusive AST developed in 15 (25%). Symptoms related to AST occurred in two of 58 patients (3%). There was a substantially increased prevalence of occlusive thrombus in patients in whom partially occluding thrombus or extrinsic compression in the inferior vena cava or ipsilateral iliofemoral veins was demonstrated on vena cavograms obtained before filter placement. The prevalence of both symptoms attributable to AST and US-detected occlusive thrombus in this series with smaller delivery systems is lower than that reported after percutaneous placement of stainless steel Greenfield filters via 29.5-F (outer diameter) sheaths. 相似文献
6.
Three dimensional computed tomographic imaging in planning the surgical approach for redo cardiac surgery after coronary revascularization. 总被引:2,自引:0,他引:2
Hrvoje Gasparovic Frank J Rybicki John Millstine Daniel Unic John G Byrne Kent Yucel Tomislav Mihaljevic 《European journal of cardio-thoracic surgery》2005,28(2):244-249
OBJECTIVE: Reoperative cardiac surgery after previous coronary artery bypass grafting represents a surgical challenge due to the potential for injury to patent coronary grafts, aorta or right ventricle. Standard preoperative imaging using a coronary angiogram and chest radiograph (CXR) often results in inaccurate assessment of mediastinal anatomy. We aimed to evaluate 3D volume rendered computed tomographic imaging as an adjunct to standard preoperative assessment of patients requiring cardiac surgery in whom coronary artery revascularization had been performed in the past. METHODS: Between January 2003 and January 2004, 33 patients with previous coronary revascularization referred for reoperative cardiac surgery underwent preoperative 3D CT imaging in order to optimize the surgical approach. The mean age in this patient population was 72+/-8 years. The combined evaluation of CXR and conventional angiography offered incomplete insight into pertinent mediastinal topography in 85% of patients (28/33). RESULTS: The correlations for distances of the left internal mammary artery (LIMA) to left anterior descending artery (LAD) graft from the midline and posterior sternum obtained by CT angiography (CTA) and CXR were poor, R=0.56 and 0.49, respectively. The correlation coefficients for distances between the right ventricle and the aorta to the sternum obtained by the same methods were similarly marginal, 0.58 and 0.48, respectively. The correlation coefficients for distances between the LIMA to LAD, circumflex and right coronary artery grafts from the midline obtained by CTA and conventional angiography were 0.54, -0.13 and 0.43, respectively. In seven patients (21%) the surgical strategy was modified based on the location of patent grafts in the mediastinum. The hospital mortality was 17% (5/29). Intraoperative injuries to vital structures were encountered in two patients (7%). No injuries to patent LIMA or the aorta were encountered. CONCLUSIONS: The 3D CT imaging technique is useful in defining the optimal surgical strategy for reoperative cardiac surgery. We found that CTA is superior to CXR and conventional angiography in defining the position of patent grafts and vital structures in relation to the midline and posterior sternum. Preoperative mapping of patent coronary grafts and other vital mediastinal structures reduces the morbidity of the reoperation through modification of surgical approaches. 相似文献
7.
Shobha Narahari Abida Juwle Subhankar Basak Dhananjaya Saranath 《Infection, genetics and evolution》2009,9(4):643-645
Viral hepatitis represents a major global health problem with 170 million Hepatitis C Virus (HCV) carriers worldwide, and 12–13 million HCV carriers in India. HCV genotypes are of clinical significance in indicating drug responsiveness and prognosis of the patient. The HCV genotypes are of epidemiologic significance as well, as they are indicative of transmission route of infection and have not been extensively studied in the Indian context. In the current study, HCV genotyping was examined in 2118 patients from different geographic regions of India. HCV was detected by PCR amplification of 5′ UTR and core-envelope1 regions, followed by genotyping using nucleotide sequencing and analysis with NCBI tool (http://www.ncbi.nlm.nih.gov/projects/genotyping/formpage.cgi). HCV genotype distribution in the 2118 Indian patients demonstrated prevalence of HCV3 (3a/3b primarily) in 62% and HCV1 (1a/1b primarily) in 31% patients. The predominance of HCV3 was significant in northern (p = 0.01) and eastern (p = 0.008) regions of India. HCV types 2, 4, 5, and 6 were detected in 0.05–4.5% of the patient group. Thus, our studies demonstrate HCV genotype prevalence in the cohort group in different regions of India. 相似文献
8.
9.
BACKGROUND: Middle ear pathology, either otitis media with effusion or
tubal dysfunction, is frequently seen in day-care centre children.
Recognition and early treatment of this condition is crucial to the
prevention of chronic otitis media, which is a major cause of hearing loss
in later life. OBJECTIVES: We aimed to reveal the incidence of silent
otitis media in day-care centre children and to determine the predisposing
factors, risk factors and the awareness of the parents of the middle ear
disease of their children. METHOD: Two hundred and thirteen children, aged
3-6 years, were screened in four daycare centres. A questionnaire was
prepared that would reveal the predisposing factors. Information was
gathered from both the parents and teachers. Children were examined by
otoscopy, pneumotoscopy, tympanometry and X-rays for sinus pathology.
RESULTS: Forty-three of 213 children had middle ear pathology; 39 of them
were confirmed by tympanometry; 56.1 % of children had some degree of sinus
pathology. We revealed that, although most of the children do not have the
risk factors, they develop middle ear pathology. Among the parents, 81.4%
of them were unaware of the condition. CONCLUSION: Early diagnosis of
middle ear pathologies is necessary for prevention of future complications.
In early stages the condition is silent. We emphasize the importance of the
primary care physician's role in diagnosing the early stages of middle ear
pathologies and recommend that teaching of otoscopic and pneumotoscopic
skills should be part of the training for family physicians.
相似文献
10.
Angelo Ferrara M.D. Ph.D. Melvin Schwartz M.D. Helen Page R.N. M.P.A. Morton Israel M.A. Yucel Atakent M.D. M.S. C. E. Smith Ph.D. Leon Landovitz Ph.D. 《Journal of community health》1988,13(1):3-18
In the past two decades, there has been a gradual trend to regionalization of perinatal care, categorization of hospitals and transport services for neonatal health care. The literature alludes to both beneficial and deleterious effects of neonatal transport (T) but no controls such as a matched nontransport (NT) population have been utilized to date.The major goal of this study was to evaluate the effect of neonatal transport from Level I and II high risk 2500 gm. neonates (born in NYC in one calendar year, 1979) compared to a cohort nontransported population matched for hospital of birth, weight, race, sex and risk. All transported 2500 gm. from Level I and II (n=328) were studied and a stratified random sample of the nontransported (NT) infants 2500 gm. from these same hospitals (n=2042) was used for comparison. The principle outcome variable was survival. The major conclusion of this study is that in Level I and II hospitals the transport group had a significantly increased survival in infants who were sick (Apgar <6) compared to cohorted nontransported controls. Interhospital differences in survival were noted among Level I and II but not seen in the subdivisions of (A) and (B) hospitals.Angelo Ferrara, M.D., Ph.D., is Professor, Pediatrics, NYU Medical Center, New York, N.Y.: Melvin Schwartz, M.D., was Research Professor, Environmental Medicine, NYU Medical Center, New York, N.Y.; Helen Page, R.N., M.P.A., is Quality Assurance Reviewer, Manhattan Eye, Ear, Throat Hospital, New York, N.Y.: Morton Israel, M.A., is Research Scientist, Health Resources Administration, City of N. Y., New York, N.Y.; Yucel Atakent, M.D., M.S., is Clinical Associate Professor, NYU Medical Center, New York, N.Y.; C.E. Smith, Ph.D., is President, Health Policy Analysis & Accountability Network, Inc. (HPAAN), Edgewood, New Mexico; Leon Landovitz, Ph.D., is Vice President, Management Information Systems, Healthways System Inc., Islin, N.J.Supported by NCHSR Grant #5-R018-HSO3832 相似文献