全文获取类型
收费全文 | 18219篇 |
免费 | 1744篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 238篇 |
儿科学 | 534篇 |
妇产科学 | 392篇 |
基础医学 | 2209篇 |
口腔科学 | 353篇 |
临床医学 | 2422篇 |
内科学 | 3521篇 |
皮肤病学 | 206篇 |
神经病学 | 1388篇 |
特种医学 | 789篇 |
外国民族医学 | 3篇 |
外科学 | 2414篇 |
综合类 | 471篇 |
一般理论 | 9篇 |
预防医学 | 1975篇 |
眼科学 | 597篇 |
药学 | 1502篇 |
2篇 | |
中国医学 | 15篇 |
肿瘤学 | 955篇 |
出版年
2021年 | 316篇 |
2020年 | 207篇 |
2019年 | 292篇 |
2018年 | 325篇 |
2017年 | 205篇 |
2016年 | 285篇 |
2015年 | 303篇 |
2014年 | 408篇 |
2013年 | 577篇 |
2012年 | 801篇 |
2011年 | 867篇 |
2010年 | 482篇 |
2009年 | 407篇 |
2008年 | 729篇 |
2007年 | 829篇 |
2006年 | 847篇 |
2005年 | 778篇 |
2004年 | 766篇 |
2003年 | 692篇 |
2002年 | 648篇 |
2001年 | 573篇 |
2000年 | 601篇 |
1999年 | 527篇 |
1998年 | 230篇 |
1997年 | 205篇 |
1996年 | 201篇 |
1995年 | 196篇 |
1994年 | 175篇 |
1993年 | 158篇 |
1992年 | 412篇 |
1991年 | 413篇 |
1990年 | 381篇 |
1989年 | 410篇 |
1988年 | 354篇 |
1987年 | 333篇 |
1986年 | 335篇 |
1985年 | 319篇 |
1984年 | 266篇 |
1983年 | 228篇 |
1982年 | 157篇 |
1981年 | 124篇 |
1979年 | 194篇 |
1978年 | 169篇 |
1977年 | 143篇 |
1976年 | 132篇 |
1975年 | 113篇 |
1974年 | 160篇 |
1973年 | 144篇 |
1972年 | 129篇 |
1971年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Bile decompression in children with histopathological evidence of pre-existing liver cirrhosis 总被引:1,自引:0,他引:1
Although it is agreed upon by most that adequate and timely bile decompression can preserve or even improve existing liver function much debate centers on whether pre-existing liver cirrhosis can also be reversed. To help answer this question we analyzed data on 47 children with choledochal cyst disease (CD) who underwent simultaneous liver biopsy during bile decompression surgery. We collected data on two groups of children with CD spanning two different time periods: January 1985 through November 1994 (Group A) and June 1995 through November 1999 (Group B). In Group A 37 children (16 boys and 21 girls ages 5 days to 10 years) underwent simultaneous liver biopsy during elective definitive surgery for CD. In Group B ten children (five boys and five girls age one month to 7 years) underwent liver biopsy twice: first during initial cyst decompression for acute obstruction and second during elective definitive surgery after resolution of acute disease. Degree of liver cirrhosis was based on a modified World Health Organization classification system (0-IV). In Group A 15/37 (40.5%) had significant liver cirrhosis at time of biopsy (III or IV) with altered liver function in all cases; eight of nine had normal liver function on follow-up, six were lost to follow-up. In Group B seven of ten (70%) had less liver cirrhosis on pathology at second operation with three unchanged; nine of ten (90%) regained normal liver function. We conclude that bile duct obstruction is the main cause of liver cirrhosis in children with CD. Adequate and timely bile decompression can restore normal liver function and even reverse severe cirrhosis. 相似文献
992.
OBJECTIVE: An evaluation of the history, design, and status of the database of the National Spinal Cord Injury Statistical Center (NSCISC) was undertaken to identify its continued relevance. RESEARCH DESIGN: A systematic review was conducted of goals, content, and quality control procedures, as well as its suitability and public availability for conducting future epidemiologic and health services research. RESULTS: The NSCISC database contains information on approximately 29,000 persons injured since 1973 and treated at any regional model spinal cord injury system within 1 year of injury. The NSCISC database is structured longitudinally with data collected at discharge, 1 year after injury, 5 years after injury, and every 5 years thereafter. The database includes information on demographics, injury severity, medical complications, surgical procedures, types and amounts of therapy, length of stay, charges, and both short-term and long-term treatment outcomes. Strengths include large sample size, use of valid and reliable measures, geographic and patient diversity, comprehensiveness, availability of long-term prospective follow-up information, good case identification, and rigorous quality control procedures. Limitations include lack of population basis, inclusion of only model system patients, losses to follow-up, and other missing data. Recent content additions include detailed information on each treatment phase, depression, substance abuse, environmental barriers to community integration, and patient identifying information. A process exists for researchers to gain access to the data. CONCLUSIONS: The database remains a valuable resource. Future plans include linkage to other databases to enhance research capability, a published research compendium, and development of a user's guide to facilitate database usage. 相似文献
993.
Kote-Jarai Z Durocher F Edwards SM Hamoudi R Jackson RA Ardern-Jones A Murkin A Dearnaley DP Kirby R Houlston R Easton DF Eeles R;CRC/BPG UK Familial Prostrate Cancer Collaborators 《Prostate cancer and prostatic diseases》2002,5(3):189-192
Epidemiological studies have suggested an association between low selenium levels and the development of prostate cancer. Human cellular glutathione peroxidase I (hGPX1) is a selenium-dependent enzyme that protects against oxidative damage and its peroxidase activity is a plausible mechanism for cancer prevention by selenium. The GPX1 gene has a GCG repeat polymorphism in exon 1, coding for a polyalanine tract of five to seven alanine residues. To test if the GPX1 GCG repeat polymorphism associates with the risk of young-onset prostate cancer we conducted a case-control study. The GPX1Ala genotypes were determined for 267 prostate cancer cases and 260 control individuals using polymerase chain reaction (PCR) amplification with fluorescently labelled primers and an ABI 377 automated genotyper. Associations between specific genotypes and the risk of prostate cancer were examined by logistic regression. We found no significant association between the GPX1 genotypes and prostate cancer. There was however an increased frequency of the GPX1Ala6/Ala6 genotype in the prostate cancer cases compared to controls (OR: 1.67; 95% CI: 0.97-2.87). The result of this study suggests that the GPX1 genotype is unlikely to be associated with the risk of developing prostate cancer. 相似文献
994.
Behavior of osteoblast,adipocyte, and myoblast markers in genome-wide expression analysis of mouse calvaria primary osteoblasts in vitro 总被引:3,自引:0,他引:3
995.
Jackson AS 《Papua and New Guinea medical journal》2002,45(3-4):222-232
The purpose of this article is to discuss 'best practice' regarding the management of a trauma victim's upper airway in a remote region of Papua New Guinea (PNG). This article has been written with the trauma patient in mind; however, much of the information would be equally relevant to the acute and chronically ill patient. Therefore the management described should be of use to aid post orderlies, community health workers, nurses and doctors alike who work or patrol in remote regions of PNG. The article is designed to take the reader through a step by step approach. Commentaries to further clarify or expand the text are placed at the end of the article under specific addendum headings, so as not to disrupt the main flow of the subject matter. In addition to upper airway management, this article also details 'ideal' emergency trauma equipment and drug requirements for bush use. 相似文献
996.
A case of an 18 year old woman is reported who presented with a pyrexia of unknown origin having returned from a trip to India. She initially had constitutional symptoms only, which rapidly progressed to a multisystem disorder. The difficulty in making the diagnosis of polyarteritis nodosa, especially with the possible differential diagnosis of infection after her recent travel, is discussed. The discussion reviews the condition of polyarteritis nodosa and analyses the diagnostic difficulties in this case. 相似文献
997.
Pradhan AD Manson JE Rossouw JE Siscovick DS Mouton CP Rifai N Wallace RB Jackson RD Pettinger MB Ridker PM 《JAMA》2002,288(8):980-987
Context Postmenopausal hormone replacement therapy (HRT) has been shown to elevate C-reactive protein (CRP) levels. Several inflammatory biomarkers, including CRP, are associated with increased cardiovascular risk. However, whether the effect of HRT on CRP represents a clinical hazard is unknown. Objectives To assess the association between baseline levels of CRP and interleukin 6 (IL-6) and incident coronary heart disease (CHD) and to examine the relationship between baseline use of HRT, CRP, and IL-6 levels as they relate to subsequent vascular risk. Design, Setting, and Participants Prospective, nested case-control study of postmenopausal women, forming part of the Women's Health Initiative, a large, nationwide, observational study. Among 75 343 women with no history of cardiovascular disease or cancer, 304 women who developed incident CHD were defined as cases and matched by age, smoking status, ethnicity, and follow-up time with 304 study participants who remained event free during a median observation period of 2.9 years. Main Outcome Measure Incidence of first myocardial infarction or death from CHD. Results Median baseline levels of CRP (0.33 vs 0.25 mg/dL; interquartile range [IQR], 0.14-0.71 vs 0.10-0.47; P<.001) and IL-6 (1.81 vs 1.47 pg/mL; IQR, 1.30-2.75 vs 1.05-2.15; P<.001) were significantly higher among cases compared with controls. In matched analyses, the odds ratio (OR) for incident CHD in the highest vs lowest quartile was 2.3 for CRP (95% confidence interval [CI], 1.4-3.7; P for trend = .002) and 3.3 for IL-6 (95% CI, 2.0-5.5; P for trend <.001). After additional adjustment for lipid and nonlipid risk factors, both inflammatory markers were significantly associated with a 2-fold increase in odds for CHD events. As anticipated, current use of HRT was associated with significantly elevated median CRP levels. However, there was no association between HRT and IL-6. In analyses comparing individuals with comparable baseline levels of either CRP or IL-6, those taking or not taking HRT had similar CHD ORs. In analyses stratified by HRT, we observed a positively graded relationship between plasma CRP levels and the OR for CHD among both users and nonusers of HRT across the full spectrum of baseline CRP. Conclusions These prospective findings indicate that CRP and IL-6 independently predict vascular events among apparently healthy postmenopausal women and that HRT increases CRP. However, use or nonuse of HRT had less importance as a predictor of cardiovascular risk than did baseline levels of either CRP or IL-6. 相似文献
998.
999.
114In(m)-labelled heat-damaged erythrocytes (HDRBC) in BDF1 mice were quantitatively much less successful in spleen targeting than in the rat. Unheated labelled cells (NRBC) were an even less effective vector. Radiobiological effects manifest in the spleen (weight loss) and white cell count were nevertheless substantial, comparable in both groups and unchanged after 14 days. Considerable early renal loss of indium is inferred in the NRBC animals, but in the HDRBC group a high proportion was retained in the liver. Progenitor cell marrow cultures indicated acute transitory lethal effects with only partial recovery at termination; the marrow concentration of indium was the same in both groups. 相似文献
1000.