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   988篇
  免费   80篇
  国内免费   13篇
儿科学   26篇
妇产科学   6篇
基础医学   59篇
口腔科学   5篇
临床医学   54篇
内科学   186篇
皮肤病学   6篇
神经病学   37篇
特种医学   106篇
外科学   107篇
综合类   24篇
预防医学   131篇
眼科学   171篇
药学   35篇
肿瘤学   128篇
  2022年   7篇
  2021年   13篇
  2020年   8篇
  2019年   16篇
  2018年   23篇
  2017年   13篇
  2016年   18篇
  2015年   13篇
  2014年   25篇
  2013年   22篇
  2012年   68篇
  2011年   65篇
  2010年   33篇
  2009年   34篇
  2008年   59篇
  2007年   68篇
  2006年   58篇
  2005年   46篇
  2004年   64篇
  2003年   42篇
  2002年   32篇
  2001年   45篇
  2000年   33篇
  1999年   21篇
  1998年   20篇
  1997年   16篇
  1996年   19篇
  1995年   16篇
  1994年   10篇
  1993年   4篇
  1992年   24篇
  1991年   15篇
  1990年   16篇
  1989年   14篇
  1988年   15篇
  1987年   14篇
  1986年   11篇
  1985年   11篇
  1984年   8篇
  1983年   5篇
  1982年   4篇
  1979年   3篇
  1977年   6篇
  1976年   5篇
  1975年   2篇
  1973年   3篇
  1972年   2篇
  1970年   2篇
  1968年   2篇
  1965年   2篇
排序方式: 共有1081条查询结果,搜索用时 0 毫秒
11.
The wound healing response is the single most important determinant of the final intraocular pressure after glaucoma surgery. The use of antiscarring agents, particularly the antimetabolites 5-fluorouracil and mitomycin C, have revolutionized glaucoma surgery over the past decade. This subject has become more important with the realization that simply lowering the intraocular pressure to below 21 mm Hg is inadequate, and that optimal lowering of the intraocular pressure should be achieved in all patients undergoing surgery for glaucoma. However, the antimetabolites still have many potential problems and side effects, some of which are potentially sightthreatening. This review concentrates on the recent publications in this field that have determined the current "state of the art," with a view toward optimizing results and minimizing side effects for our patients with glaucoma in this exciting and challenging area of progress.  相似文献   
12.
Abstract: We report the first case of fatal anthrax meningoencephalitis in Hong Kong over the past 60 years. A 13 year-old boy presented with right lower quadrant pain, diarrhoea and progressive headache. Lumbar puncture yielded gram positive bacilli initially thought to be Bacillus cereus, a contaminant. He was treated with ampicillin and cefotaxime, but died 3 days after hospitalization. The organism isolated from blood and cerebrospinal fluid was later identified as Bacillus anthracis.  相似文献   
13.
We examined the relationship between a functional polymorphism (667C-- >T, ala-->val) of the methylenetetrahydrofolate reductase gene (MTHFR) and the risk of colorectal adenomas in the prospective Nurses' Health Study. Among 257 incident polyp cases and 713 controls, the MTHFR val/val polymorphism [relative risk (RR) = 1.35, 95% confidence interval (CI) 0.84-2.17] was not significantly associated with risk of adenomas. This lack of association was observed for both small (RR = 1.36, 95% CI 0.76-2.45) and large (RR = 1.32, 95% CI 0.66-2.66) adenomas. Furthermore, there was no significant interaction between this polymorphism and consumption of either folate, methionine or alcohol. We also examined the relationship of a newly identified polymorphism (asp919gly) of the methionine synthase gene (MS) with the risk of colorectal adenomas in the same population. The MS gly/gly polymorphism was also not significantly associated with risk of colorectal adenomas (RR = 0.66, 95% CI 0.26-1.70). These results, which need to be confirmed in other studies, suggest that the MTHFR val/val polymorphism, which has been previously inversely associated with risk of colorectal cancer, plays a role only in a late stage (adenoma-- >carcinoma) of colorectal tumorigenesis, and/or may protect against malignant transformation in the subset of benign adenomas, which may progress to malignancy.   相似文献   
14.
Moyamoya disease and spontaneous internal carotid artery dissections are rare conditions, but both tend to affect young adults with potentially devastating consequences. A 43-year-old non-Japanese patient presented with neurological symptoms, which, following carotid Doppler ultrasound and angiography, was labelled as being due to a spontaneous internal carotid artery dissection. Repeat imaging at 3 months showed normalisation of the carotid Doppler findings which coincided with the formation of „moyamoya” vessels on the angiogram. This case report illustrates the changes on carotid ultrasound in early moyamoya disease which may mimic the appearances of an internal carotid artery dissection and demonstrates the change of the spectral Doppler waveform that occurs with the formation of new vessels at the base of the brain. Received: 20 August 1998; Revision received: 23 November 1998; Accepted: 23 December 1998  相似文献   
15.
Esther Molina‐Montes  María‐Jos Snchez  Raul Zamora‐Ros  H.B Bueno‐de‐Mesquita  Petra A. Wark  Mireia Obon‐Santacana  Tilman Kühn  Verena Katzke  Ruth C. Travis  Weimin Ye  Malin Sund  Alessio Naccarati  Amalia Mattiello  Vittorio Krogh  Caterina Martorana  Giovanna Masala  Pilar Amiano  Jos‐María Huerta  Aurelio Barricarte  Jos‐Ramn Quirs  Elisabete Weiderpass  Lene Angell sli  Guri Skeie  Ulrika Ericson  Emily Sonestedt  Petra H. Peeters  Isabelle Romieu  Augustin Scalbert  Kim Overvad  Matthias Clemens  Heiner Boeing  Antonia Trichopoulou  Eleni Peppa  Pavlos Vidalis  Kay‐Tee Khaw  Nick Wareham  Anja Olsen  Anne Tjnneland  Marie‐Christine Boutroun‐Rualt  Franoise Clavel‐Chapelon  Amanda J. Cross  Yunxia Lu  Elio Riboli  Eric J. Duell 《International journal of cancer. Journal international du cancer》2016,139(7):1480-1492
Despite the potential cancer preventive effects of flavonoids and lignans, their ability to reduce pancreatic cancer risk has not been demonstrated in epidemiological studies. Our aim was to examine the association between dietary intakes of flavonoids and lignans and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. A total of 865 exocrine pancreatic cancer cases occurred after 11.3 years of follow‐up of 477,309 cohort members. Dietary flavonoid and lignan intake was estimated through validated dietary questionnaires and the US Department of Agriculture (USDA) and Phenol Explorer databases. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated using age, sex and center‐stratified Cox proportional hazards models, adjusted for energy intake, body mass index (BMI), smoking, alcohol and diabetes status. Our results showed that neither overall dietary intake of flavonoids nor of lignans were associated with pancreatic cancer risk (multivariable‐adjusted HR for a doubling of intake = 1.03, 95% CI: 0.95–1.11 and 1.02; 95% CI: 0.89–1.17, respectively). Statistically significant associations were also not observed by flavonoid subclasses. An inverse association between intake of flavanones and pancreatic cancer risk was apparent, without reaching statistical significance, in microscopically confirmed cases (HR for a doubling of intake = 0.96, 95% CI: 0.91–1.00). In conclusion, we did not observe an association between intake of flavonoids, flavonoid subclasses or lignans and pancreatic cancer risk in the EPIC cohort.  相似文献   
16.
背景和目的:罗格列酮与阿伐他汀联合疗法已经被证实对于2型糖尿病患者的血糖控制以及脂质水平都有益处。本试验将通过检测罗格列酮与阿伐他汀联合疗法对于2型糖尿病患者的生物标记水平的作用来研究该联合疗法对血管炎的作用。方法:30例患有2型糖尿病和高脂血症的患者被纳入治疗。对这些患者给予罗格列酮单一疗法4mg/d,持续3个月,然后在接下来的3个月中给予这些患者阿伐他汀10mg/d作为联合疗法。在研究开始时,罗格列酮单一疗法之后以及罗格列酮与阿伐他汀联合治疗之后测量炎性生物标记物,包括高敏C-反应蛋白(hs-CRP)、基质金属蛋白酶9(MMP…  相似文献   
17.
PURPOSE: Proliferative vitreoretinopathy (PVR) is a major cause of failure of retinal detachment surgery. It is believed to be a wound-healing process in the retina. Many of the cellular functions are influenced by cytokines and growth factors such as interleukins (ILs). The present study was conducted to investigate the presence of transforming growth factor-beta 2 (TGF-beta2), basic fibroblast growth factor (bFGF), IL-1beta, IL-6, and protein in the vitreous of patients with retinal detachment and to determine the value of these mediators in predicting the future development of PVR. METHODS: A prospective study was conducted in 140 consecutive patients with rhegmatogenous retinal detachment in whom vitrectomy was considered necessary. Vitreous samples were analyzed for the presence of TGF-beta2, bFGF, IL-1beta, IL-6, and protein. Patients were then followed up for 3 months for the development of postoperative PVR. RESULTS: The mean levels of TGF-beta2, bFGF, IL-1beta, and protein in the vitreous were significantly higher (P < 0.05) in patients with preoperative PVR compared with those without. The mean levels of TGF-beta2, bFGF, IL-6, and protein in the vitreous were significantly higher (P < 0.05) in patients who had postoperative PVR compared with those who did not. Multivariate logistic regression analysis showed IL-6 and protein to be significant (P < 0.05), independent, predictive risk factors for the development of PVR. CONCLUSIONS: The various cytokines may play a role in the pathobiology of PVR. High vitreous levels of IL-6 and protein were identified as significant risk factors for PVR. A model was developed to predict the probability of development of postoperative PVR in these patients, and it may be used to indicate intravitreal pharmacologic treatment for those at risk.  相似文献   
18.

Background

Dietary oleic acid may prevent pancreatic ductal adenocarcinoma (PDA) by reducing hyperinsulinaemia which can otherwise promote DNA damage and tumour growth. Results from previous epidemiological studies investigating oleic acid are inconsistent. This study aims to clarify the relationship between dietary oleic acid intake and the risk of developing PDA using nutritional information from food diaries plus published serum biomarker data from HbA1c.

Methods

23,658 participants, aged 40–74 years, were recruited into EPIC-Norfolk and completed 7-day food diaries which recorded; foods, brands and portion sizes to calculate nutrient intakes. Serum HbA1c was measured at recruitment in 11,147 participants (48.7% of cohort). Hazard ratios (HRs) for quintiles of dietary oleic acid intake and serum HbA1c were estimated using Cox regression. Additional analyses were made according to whether body mass index (BMI) was greater or less than 25?kg/m2 as this influences hyperinsulinaemia.

Results

88 participants (55% women) developed PDA after a mean follow-up of 8.4 years (SD?=?3.9) (mean age at diagnosis?=?72.6 years, SD?=?8.8). A decreased risk of PDA was associated with increased dietary oleic acid intake (highest vs lowest quintile, HR?=?0.29, 95% CI?=?0.10–0.81, P trend across quintiles?=?0.011), with statistical significance maintained when BMI>25?kg/m2 but not if BMI<25?kg/m2. An elevated serum HbA1c was associated with increased risk of disease (highest vs lowest quintiles, HR?=?6.32, 95% CI?=?1.38–28.89, P for trend?=?0.004).

Conclusions

The data supports a protective role of oleic acid against development of PDA in those with higher BMIs possibly through influencing hyperinsulinaemia. Oleic acid intake should be accurately measured in future aetiological studies.  相似文献   
19.
BACKGROUND: American College of Cardiology/American Heart Association guidelines for the diagnosis and management of heart failure recommend investigating exacerbating conditions such as thyroid dysfunction, but without specifying the impact of different thyroid-stimulation hormone (TSH) levels. Limited prospective data exist on the association between subclinical thyroid dysfunction and heart failure events. METHODS AND RESULTS: We performed a pooled analysis of individual participant data using all available prospective cohorts with thyroid function tests and subsequent follow-up of heart failure events. Individual data on 25 390 participants with 216 248 person-years of follow-up were supplied from 6 prospective cohorts in the United States and Europe. Euthyroidism was defined as TSH of 0.45 to 4.49 mIU/L, subclinical hypothyroidism as TSH of 4.5 to 19.9 mIU/L, and subclinical hyperthyroidism as TSH <0.45 mIU/L, the last two with normal free thyroxine levels. Among 25 390 participants, 2068 (8.1%) had subclinical hypothyroidism and 648 (2.6%) had subclinical hyperthyroidism. In age- and sex-adjusted analyses, risks of heart failure events were increased with both higher and lower TSH levels (P for quadratic pattern <0.01); the hazard ratio was 1.01 (95% confidence interval, 0.81-1.26) for TSH of 4.5 to 6.9 mIU/L, 1.65 (95% confidence interval, 0.84-3.23) for TSH of 7.0 to 9.9 mIU/L, 1.86 (95% confidence interval, 1.27-2.72) for TSH of 10.0 to 19.9 mIU/L (P for trend <0.01) and 1.31 (95% confidence interval, 0.88-1.95) for TSH of 0.10 to 0.44 mIU/L and 1.94 (95% confidence interval, 1.01-3.72) for TSH <0.10 mIU/L (P for trend=0.047). Risks remained similar after adjustment for cardiovascular risk factors. CONCLUSION: Risks of heart failure events were increased with both higher and lower TSH levels, particularly for TSH ≥10 and <0.10 mIU/L.  相似文献   
20.
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