全文获取类型
收费全文 | 9769篇 |
免费 | 642篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 62篇 |
儿科学 | 324篇 |
妇产科学 | 248篇 |
基础医学 | 1080篇 |
口腔科学 | 437篇 |
临床医学 | 1033篇 |
内科学 | 1890篇 |
皮肤病学 | 103篇 |
神经病学 | 843篇 |
特种医学 | 580篇 |
外科学 | 1308篇 |
综合类 | 426篇 |
一般理论 | 11篇 |
预防医学 | 993篇 |
眼科学 | 194篇 |
药学 | 481篇 |
中国医学 | 12篇 |
肿瘤学 | 399篇 |
出版年
2021年 | 133篇 |
2020年 | 67篇 |
2019年 | 127篇 |
2018年 | 138篇 |
2017年 | 117篇 |
2016年 | 116篇 |
2015年 | 147篇 |
2014年 | 208篇 |
2013年 | 346篇 |
2012年 | 435篇 |
2011年 | 456篇 |
2010年 | 268篇 |
2009年 | 262篇 |
2008年 | 401篇 |
2007年 | 452篇 |
2006年 | 415篇 |
2005年 | 409篇 |
2004年 | 384篇 |
2003年 | 345篇 |
2002年 | 361篇 |
2001年 | 291篇 |
2000年 | 291篇 |
1999年 | 266篇 |
1998年 | 167篇 |
1997年 | 134篇 |
1996年 | 135篇 |
1995年 | 107篇 |
1994年 | 120篇 |
1993年 | 108篇 |
1992年 | 228篇 |
1991年 | 219篇 |
1990年 | 241篇 |
1989年 | 223篇 |
1988年 | 229篇 |
1987年 | 231篇 |
1986年 | 201篇 |
1985年 | 199篇 |
1984年 | 110篇 |
1983年 | 110篇 |
1982年 | 80篇 |
1981年 | 84篇 |
1980年 | 68篇 |
1979年 | 90篇 |
1978年 | 88篇 |
1977年 | 69篇 |
1976年 | 56篇 |
1975年 | 57篇 |
1974年 | 59篇 |
1972年 | 59篇 |
1971年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
E Shmueli M F Myszor D Burke C O Record K Matthewson 《The British journal of surgery》1992,79(8):778-780
Of 86 patients with inoperable malignant dysphagia, 68 (79 per cent) underwent successful palliation by endoscopic laser therapy, of whom 24 remained well palliated until the time of death. In 18 patients laser treatment was unsuccessful and nine of these underwent intubation, eight successfully. After successful laser therapy, dysphagia recurred in 44 patients a mean of 7.8 weeks later. Of these, 31 received palliation until death by dilatation with or without laser therapy, and 13 required intubation. The overall laser-related complication rate was 12 per cent with a mortality rate of 4 per cent. The intubation-related mortality rate was 9 per cent. 相似文献
33.
Smoking in Pregnancy and Parenthood: What is the Role of Depression, Anxiety and Nicotine Addiction?
Leona Bull Ronan Burke Siobhan Walsh Emma Whitehead 《Early child development and care》2003,173(2):349-356
This paper presents some of the findings from the Smoking in Pregnancy study of attitudes towards smoking among pregnant women, mothers of young children and their partners in East Surrey. As part of the study, respondents completed a General Health Questionnaire to identify mental health difficulties and, if they were smoking at the time of the study, they also completed the Fagerstrom nicotine addiction test. Eleven female respondents had high scores on the General Health Questionnaire, suggesting symptoms of depression, anxiety and/or social dysfunction for these women. There was no evidence that smokers were suffering from greater mental health difficulties than ex-smokers or non-smokers. However, the General Health Questionnaire scores of smokers were positively associated with their level of nicotine dependence. Furthermore, when General Health Questionnaire scores of all respondents were compared with self-reported health status there was a marked discrepancy suggesting under-reporting of symptoms by women. 相似文献
34.
A kinetic study of leucine metabolism in severely burned patients. Comparison between a conventional and branched-chain amino acid-enriched nutritional therapy.
下载免费PDF全文
![点击此处可从《Annals of surgery》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A cross-over design study was used to examine the metabolic consequences of enteral feeding for 48 to 96 hours with either a branched-chain amino acid (BCAA)-enriched (44% BCAA) or a conventional egg protein formulation in 12 severely burned adult patients. A stable isotope labeled leucine (L-1-13C-leucine) tracer approach was used to measure leucine flux and oxidation and to estimate rates of whole body protein synthesis and breakdown. Additionally, 15N2-urea and 6,6-2H-glucose were administered to assess the status of urea and glucose kinetics with these two nutritional treatments. Average patient age was 54 years, and average burn surface area was 36%. Studies were conducted at an average of 25 days postburn. Leucine flux and oxidation were significantly (p less than 0.01, by paired t-test) elevated with BCAA feeding as compared to the egg protein formulation. However, there were no significant differences in the rates of leucine incorporation into, or release from, proteins (p greater than 0.05) between the two dietary periods. Mean rates of body protein synthesis and breakdown for each diet were about twice the rates reported for healthy young adults. Apparent nitrogen balance measurements were not statistically different (p greater than 0.1) between the two diet periods. Furthermore, urea and glucose kinetics failed to show significant differences between the two diet periods. It appears from these results that the major consequences of increased intake of leucine from the BCAA formula is an enhanced rate of leucine oxidation. In conclusion, (1) the availability of BCAAs is not rate-limiting for enhanced protein synthesis in burn patients, and (2) the use of enriched BCAA formulas in burn therapy does not appear to offer advantages over a routinely used enteral egg protein formula, at least based on the present determinations. 相似文献
35.
Jonathan M Hodgson Kevin D Croft Trevor A Mori Valerie Burke Lawrence J Beilin Ian B Puddey 《The Journal of nutrition》2002,132(1):55-58
Prospective studies suggest that tea may protect against cardiovascular disease. A potential mechanism for such an effect involves inhibition of lipid peroxidation by polyphenolic antioxidants derived from tea. Our objective was to determine whether regular ingestion of tea could inhibit in vivo lipid peroxidation. Two controlled intervention studies assessed the effects of regular ingestion of tea on lipid peroxidation determined by measurement of urinary F(2)-isoprostane excretion. Study 1: The effects of 1000 mL/d of green tea and black tea were compared with hot water containing caffeine in 13 subjects with elevated blood pressure using a randomized 3-period (7 d each) crossover design. Study 2: The effects of 1250 mL/d of black tea were compared with hot water in 22 subjects with mildly raised serum total cholesterol concentrations using a randomized 2-period (4 wk each) crossover design. F(2)-isoprostane excretion was not altered after regular ingestion of green tea (273 +/- 48 pmol/mmol creatinine) or black tea (274 +/- 39 pmol/mmol creatinine) in comparison with hot water (263 +/- 47 pmol/mmol creatinine; Study 1), or by regular ingestion of black tea (334 +/- 71 pmol/mmol creatinine) in comparison with hot water (355 +/- 75 pmol/mmol creatinine; Study 2). These results do not support the suggestion that polyphenolic antioxidants derived from tea inhibit in vivo lipid peroxidation. 相似文献
36.
37.
38.
39.
Michael F Grunebaum Hanga C Galfalvy C Matthew Nichols Nathilee A Caldeira Leo Sher Kanita Dervic Ainsley K Burke J John Mann Maria A Oquendo 《Bipolar disorders》2006,8(5P1):496-502
Objectives: The goal of this retrospective study was to examine factors differentiating persons with bipolar disorder who did or did not have comorbid lifetime substance use disorders (SUD) at an index assessment. We also explored the chronology of onset of mood and SUD.
Methods: We studied 146 subjects with DSM-defined bipolar disorder. Subgroups with and without lifetime SUD were compared on demographic and clinical measures.
Results: Substance abuse disorders in this bipolar sample were associated with male sex, impulsive-aggressive traits, comorbid conduct and Cluster B personality disorders, number of suicide attempts and earlier age at onset of a first mood episode. In a multivariable logistic regression analysis, male sex and aggression and possibly earlier age at mood disorder onset were associated with SUD. In those with or without SUD, the first mood episode tended to be depressive and to precede the onset of SUD.
Conclusions: In persons with bipolar disorder, an earlier age of onset and aggressive traits appear to be factors associated with later development of comorbid SUD. 相似文献
Methods: We studied 146 subjects with DSM-defined bipolar disorder. Subgroups with and without lifetime SUD were compared on demographic and clinical measures.
Results: Substance abuse disorders in this bipolar sample were associated with male sex, impulsive-aggressive traits, comorbid conduct and Cluster B personality disorders, number of suicide attempts and earlier age at onset of a first mood episode. In a multivariable logistic regression analysis, male sex and aggression and possibly earlier age at mood disorder onset were associated with SUD. In those with or without SUD, the first mood episode tended to be depressive and to precede the onset of SUD.
Conclusions: In persons with bipolar disorder, an earlier age of onset and aggressive traits appear to be factors associated with later development of comorbid SUD. 相似文献
40.
J B Croft J L Cresanta L S Webber S R Srinivasan D S Freedman G L Burke G S Berenson 《Southern medical journal》1988,81(3):341-9, 353
Fasting serum lipids, lipoprotein cholesterol, and other cardiovascular disease risk factors were examined in 321 natural parents of children with low and/or high levels of beta- and pre-beta-lipoprotein cholesterol. Parents of children from low pre-beta-lipoprotein groups had elevated alpha- and lower pre-beta-lipoprotein cholesterol levels. Parents whose children had high beta-lipoprotein cholesterol levels also had high serum total and beta-lipoprotein cholesterol levels. Parents of children with high levels of both beta- and pre-beta-lipoprotein cholesterol had a high prevalence of both abnormal risk factor levels, as well as clinical evidence of early coronary artery disease (before age 50 years). These observations show that parents of children with high beta- and/or pre-beta-lipoprotein cholesterol levels have greatly enhanced risk for cardiovascular disease, and children mirror their parents' lipoprotein cholesterol levels. These observations emphasize the need for cardiovascular risk evaluation early in life, especially in high-risk families. 相似文献