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   10281篇
  免费   1013篇
  国内免费   94篇
耳鼻咽喉   6篇
儿科学   834篇
妇产科学   27篇
基础医学   1714篇
口腔科学   179篇
临床医学   387篇
内科学   846篇
皮肤病学   140篇
神经病学   398篇
特种医学   42篇
外科学   125篇
综合类   598篇
一般理论   1篇
预防医学   4705篇
眼科学   17篇
药学   963篇
  3篇
中国医学   271篇
肿瘤学   132篇
  2024年   15篇
  2023年   154篇
  2022年   462篇
  2021年   932篇
  2020年   486篇
  2019年   465篇
  2018年   417篇
  2017年   390篇
  2016年   397篇
  2015年   469篇
  2014年   596篇
  2013年   977篇
  2012年   542篇
  2011年   581篇
  2010年   426篇
  2009年   383篇
  2008年   412篇
  2007年   436篇
  2006年   307篇
  2005年   290篇
  2004年   258篇
  2003年   239篇
  2002年   204篇
  2001年   179篇
  2000年   131篇
  1999年   123篇
  1998年   115篇
  1997年   89篇
  1996年   95篇
  1995年   88篇
  1994年   81篇
  1993年   58篇
  1992年   71篇
  1991年   46篇
  1990年   47篇
  1989年   41篇
  1988年   50篇
  1987年   36篇
  1986年   32篇
  1985年   42篇
  1984年   33篇
  1983年   29篇
  1982年   31篇
  1981年   23篇
  1980年   18篇
  1979年   19篇
  1978年   25篇
  1977年   11篇
  1976年   15篇
  1975年   8篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
[目的]了解供机食品的卫生状况,分析鉴定目的菌的特性。[方法]依据相关国家标准及VITEK操作手册对病原微生物进行检验和鉴定。[结果]从1份供机食品-豇豆中同时检出屎肠球菌、坚韧肠球菌及大肠杆菌,分别具有这3种病原菌的典型培养特性、菌体特征及生化特性。[结论]日常工作中应重视对多种病原菌的检验及加强对供机食品从原料到成品的全过程卫生监控,以保障工作人员及乘客的生命安全。  相似文献   
42.
43.
44.
We have studied 21 babies with IgE-mediated food allergy (FA) sensitized via breast milk. The diagnosis of IgE-mediated FA was based on the response to elimination diet and challenge tests, and was confirmed by positive RAST and skin tests. The children exhibited immediate symptoms, such as urticaria, angioedema, and asthma. Only 5/21 children developed tolerance to the offending food at the median age of 14 years. The children who failed to develop tolerance still have high levels of IgE antibodies towards the offending food. In conclusion, the results of our long-term follow-up study show that the natural history of FA in children sensitized via breast milk may be less optimistic than generally reported.  相似文献   
45.
The dietary intake and urinary output of iodine and the thyroid activity was measured in 12 living food eaters (people consuming uncooked, Lactobacilli rich vegan food) and omnivores. Seven day food record was used for calculating the dietary iodine intake, instrumental neutron activation analysis for measuring the urinary iodine output and RIA for determining of the thyroid hormones (TSH and FT4). The living food eaters were divided into two groups according to urinary iodine output: high iodine group (≥900 ug/d) and low iodine group (<200 ug/d). Thyroid activity in both groups was with in normal range. Dietary intake of iodine was dependent on the the use of seaweed. The highest amounts of dietary iodine observed in the present study, as assessed by the the urinary iodine output, can be harmful for susceptible subjects. On the other hand the calculated intake of iodine by living food eaters didn't fill the RDA. As an conclusion on a living food diet one has to ensure the sufficient intake of iodine by consuming seaweed or Kelp tablets daily. However the intake of these preparations needs to be kept at reasonble limits due to their possible high iodine content. More information of the iodine content of different seaweeds and seaweed products is needed.  相似文献   
46.
Background: It has been suggested that oral cobalamin (vitamin B12) therapy may be an effective therapy for treating cobalamin deficiencies related to food‐cobalamin malabsorption. However, the duration of this treatment was not determined. Patients and method: In an open‐label, nonplacebo study, we studied 30 patients with established cobalamin deficiency related to food‐cobalamin malabsorption, who received between 250 and 1000 μg of oral crystalline cyanocobalamin per day for at least 1 month. Endpoints: Blood counts, serum cobalamin and homocysteine levels were determined at baseline and during the first month of treatment. Results: During the first month of treatment, 87% of the patients normalized their serum cobalamin levels; 100% increased their serum cobalamin levels (mean increase, +167 pg/dl; P < 0.001 compared with baseline); 100% had evidence of medullary regeneration; 100% corrected their initial macrocytosis; and 54% corrected their anemia. All patients had increased hemoglobin levels (mean increase, +0.6 g/dl) and reticulocyte counts (mean increase, +35 × 106/l) and decreased erythrocyte cell volume (mean decrease, 3 fl; all P < 0.05). Conclusion: Our findings suggest that crystalline cyanocobalamin, 250–1000 μg /day, given orally for 1 month, may be an effective treatment for cobalamin deficiencies not related to pernicious anemia.  相似文献   
47.
An Historical Perspective from the Green Revolution to the Gene Revolution   总被引:2,自引:0,他引:2  
W Paul Davies  MSc  PhD 《Nutrition reviews》2003,61(S6):S124-134
Since the 1960s conventional crop breeding has increased food production commesurate with the growing population. For agricultural development to continue, the exploitation of greater genetic diversity and modern biotechnology are becoming increasingly important. This article reviews the milestones achieved by the Green Revolution and many of the recent breakthroughs of modern biotechnology.  相似文献   
48.
Investigators have tried to identify a level of seric specific immunoglobulin E (IgE) that had a sufficient predictive value to diagnose a food allergy without having will resort to the food challenge. To search in literature, all the studies that have estimated the possibility to identify a level of seric specific cow milk IgE with a positive predictive value (PPV) of 95% for the first diagnosis of cow's milk allergy (CMA) in pediatric age. We have identified six studies, nearly all studies suffer from relevant methodological bias. Proposed cut-off are all different. The studied pediatric populations were highly selected. Also neglecting the methodological bias of the studies and the great difference of value between the proposed cut-off, it always remains to consider that the pre-test probability of having a CMA between the children enrolled in the six studies included in this review is particularly high. The likelihood ratio helps to transfer the results of a study on a diagnostic test just to our population, and it is more realistic rather than to entrust itself to the PPV or the negative predictive value, that are much influenced from the prevalence of the disease in the studied population.  相似文献   
49.
Cutaneous allergy to mustard in a salad maker   总被引:1,自引:0,他引:1  
A case of allergic contact dermatitis to mustard (Brassica nigra) in a salad maker is reported. The sources of skin contact included a commercial salad cream, a vinegrette, and various members of the mustard family, Cruciferae. The Cruciferae family includes many salad vegetables and condiments which contain allergenic isothiocyanates. The extent of skin contact among salad makers and other food handlers may be significant, and sensitization to isothiocyanates from this large family of vegetables may be an important cause of food contact allergy in these individuals.  相似文献   
50.
Summary Eight healthy volunteers participated in an open crossover study to assess the effect of a standardised meal on the systemic availability of a single oral dose of fenoldopam mesylate 100 mg. Subjects were studied on four separate occasions, twice fasting and twice fed in randomised, balanced order. Plasma and urine samples were obtained before and at regular intervals up to 25 h post dose. Measurement of fenoldopam (SK&F 82526) and its 8-sulphate metabolite (SK&F 87782) were by means of HPLC-EC analysis. Area under the plasma concentration time curve (AUC) and maximum detected plasma concentration (Cmax) for fenoldopam and SK&F 87782 were significantly reduced whereas time to maximum concentration was significantly increased with food. Using AUC's for fenoldopam and SK&F 87782, mean relative bioavailabilities were 35% and 81% respectively under fed compared with fasting conditions. Twenty-four hour excretion of fenoldopam was significantly reduced with food, but excretion of SK&F 87782 was apparently unchanged. Mean relative bioavailabilities calculated from these data were 83% and 86% respectively. Relatively large inter-subject variability in AUC and Cmax were seen, but intra-subject variability was not marked. Mild symptoms associated with vasodilation were reported on all study days.  相似文献   
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