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   1395篇
  免费   70篇
  国内免费   3篇
耳鼻咽喉   10篇
儿科学   41篇
妇产科学   19篇
基础医学   189篇
口腔科学   33篇
临床医学   95篇
内科学   358篇
皮肤病学   26篇
神经病学   157篇
特种医学   21篇
外科学   108篇
综合类   14篇
一般理论   1篇
预防医学   92篇
眼科学   31篇
药学   144篇
中国医学   10篇
肿瘤学   119篇
  2024年   3篇
  2023年   14篇
  2022年   33篇
  2021年   50篇
  2020年   39篇
  2019年   28篇
  2018年   31篇
  2017年   18篇
  2016年   40篇
  2015年   32篇
  2014年   47篇
  2013年   74篇
  2012年   102篇
  2011年   110篇
  2010年   56篇
  2009年   40篇
  2008年   62篇
  2007年   81篇
  2006年   76篇
  2005年   71篇
  2004年   97篇
  2003年   90篇
  2002年   104篇
  2001年   17篇
  2000年   8篇
  1999年   14篇
  1998年   19篇
  1997年   14篇
  1996年   11篇
  1995年   10篇
  1994年   9篇
  1993年   11篇
  1992年   11篇
  1991年   5篇
  1990年   7篇
  1989年   2篇
  1987年   3篇
  1986年   2篇
  1984年   2篇
  1983年   7篇
  1982年   2篇
  1981年   2篇
  1980年   6篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1974年   1篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
排序方式: 共有1468条查询结果,搜索用时 15 毫秒
21.
Kihara  Mari  Sugihara  Takahiko  Asano  Junichi  Sato  Midori  Kaneko  Hiroshi  Muraoka  Sei  Ohshima  Shiro  Nanki  Toshihiro 《Clinical rheumatology》2022,41(12):3661-3673
Clinical Rheumatology - To describe clinical characteristics of patients in Japan with coronavirus disease 19 (COVID-19) and pre-existing rheumatic disease and examine the possible risk factors...  相似文献   
22.
23.
Quercetin is a promising food component, which can prevent lifestyle related diseases. To understand the dietary intake of quercetin in the subjects of a population-based cohort study and in the Japanese population, we first determined the quercetin content in foods available in the market during June and July in or near a town in Hokkaido, Japan. Red leaf lettuce, asparagus, and onions contained high amounts of quercetin derivatives. We then estimated the daily quercetin intake by 570 residents aged 20–92 years old in the town using a food frequency questionnaire (FFQ). The average and median quercetin intakes were 16.2 and 15.5 mg day−1, respectively. The quercetin intakes by men were lower than those by women; the quercetin intakes showed a low correlation with age in both men and women. The estimated quercetin intake was similar during summer and winter. Quercetin was mainly ingested from onions and green tea, both in summer and in winter. Vegetables, such as asparagus, green pepper, tomatoes, and red leaf lettuce, were good sources of quercetin in summer. Our results will help to elucidate the association between quercetin intake and risks of lifestyle-related diseases by further prospective cohort study and establish healthy dietary requirements with the consumption of more physiologically useful components from foods.  相似文献   
24.
We have established an ELISA for detecting thrombin cleavage of the FVIII light chain at Arg1689. The method used a coating alloantibody which recognized amino acid residues 2248–2312 in the C2 domain, together with a second monoclonal antibody, NMC-VIII/10, which recognized residues 1675–1684 in the amino-terminal region of the light chain. FVIII antigen (FVIII:Ag) was measured after treatment of plasma with various concentrations of thrombin. The FVIII:Ag of normal plasma was reduced in a dose-dependent manner by the thrombin, falling to 28% in the presence of 100 U/ml enzyme. The concentration of thrombin that achieved 50% reduction (IC50) was approximately 1·0 U/ml. The plasma of four haemophilia A positive (A+) and two haemophilia A reduced (AR) patients were analysed. The IC50 of all patients was more than 1·0 U/ml, indicating that thrombin cleavage of the FVIII light chain was defective. One haemophilia A+ plasma did not respond to thrombin in this ELISA system. The patient (TI) was a haemophiliac with FVIII coagulant activity of 0·04 U/ml and FVIII:Ag of 1·78 U/ml. In addition, immunoblotting of the purified FVIII from TI showed that thrombin cleavage of the 80 kilodalton (kD) light chain was impaired. The patient's DNA was amplified using the polymerase chain reaction with a set of synthetic oligonucleotide primers spanning amino acid residues 1646–1714. Sequence analysis of the amplified DNA fragments revealed a cytosine to thymine transition, converting an arginine 1689 to cysteine. This abnormal FVIII was designated as FVIII Hiroshima. Our ELISA system is a simple and useful method of evaluating the proteolytic cleavage by thrombin at Arg1689.  相似文献   
25.
26.
27.
To investigate the association of westernized food habits and concentrations of serum lipids in the Japanese, we studied 1200 healthy Japanese living in Hiroshima prefecture and 1483 ethnic Japanese from Hiroshima prefecture living in the Hawaii Islands and Los Angeles. The nutritional assessments were made by the same dietitians. No major difference was observed in the total energy intake between the Japanese and the Japanese-Americans in both males and females. However, the intake of animal fat and simple carbohydrates (especially fructose) were markedly greater, and that of complex carbohydrates lower, in the Japanese-Americans compared with the Japanese. The mean serum cholesterol (CH), LDL-CH and serum triglyceride (TG) levels were significantly higher in the Japanese-Americans in both sexes. The mean HDL-CH concentration was similar between the two groups in males, but it was approximately 7 mg/dl higher in Japanese-American females. Using the 75 percentile values of CH and TG in the Japanese in Hiroshima, the frequency of WHO types IIa and IIb hyperlipidemia was about twice as high in the Japanese-Americans. These results suggest that westernized food habits in the Japanese include qualitative changes in animal fat, simple carbohydrate and complex carbohydrate diet rather than an increase in the total energy intake. These changes are associated with marked increases in the concentrations of serum CH and TG and increased prevalence of types IIa and IIb hyperlipidemia.  相似文献   
28.
BACKGROUND: Contamination of bronchoalveolar lavage fluid is a major problem in the world. Although 2% glutaraldehyde (GA) is widely used as a disinfectant for bronchoscope cleaning, recently, GA-tolerant mycobacteria have been isolated, which makes this problem more complicated. METHODS: We studied the susceptibility to GA and antibiotics of mycobacteria isolated from bronchoscope washing machines in our hospital. We also studied the minimum inhibitory concentrations of GA and antibiotics with pump inhibitors. RESULTS: Twenty-nine mycobacteria were isolated, of which 26 were Mycobacterium chelonae. Among 18 isolates of M chelonae, excluding 8 isolates in which some results were not reproducible, 50% (9 of 18) were 2% GA-tolerant. One hundred percent (9 of 9) of the GA-tolerant isolates and 11% (1 of 9) of the GA-sensitive isolates were either resistant or intermediately resistant to 2 or 3 classes of antibiotics. Efflux pump inhibitors did not influence the susceptibility to GA and antibiotics. CONCLUSIONS: It was suggested that there might be an association of GA tolerance with antibiotic resistance in M chelonae. There may a different mechanism(s) other than that involving efflux pumps with regard to GA tolerance and antibiotic resistance in M chelonae. When bronchoscopy-related mycobacterial infections are suspected, physicians and clinical microbiologists should exercise care in handling GA-tolerant mycobacteria, which may be resistant to multiple antibiotics.  相似文献   
29.
In this study, we verified the possible role of cyclophosphamide (CY) in protecting or not against neuronal losses in young and aged male Calomys callosus chronically infected with the MORC-1 strain of Trypanosoma cruzi through numerical quantification of neurons from the myenteric plexus of the colon and quantification of nitric-oxide concentration (NO) during the acute and chronic phase of infection. For this purpose, groups of young C. callosus were infected with the MORC-1 strain of T. cruzi. A group of infected animals received i.p. 0.2 mg/ml genuxal dissolved in distilled water treatment with CY. NO concentration in aged animals displayed reduced levels when compared to those found in young animals. No significant alterations in the number of neurons were observed in young animals, but for aged ones, a protective role of CY in reducing neuron loss was noted, in addition to enhancing the neuronal volume, area, and perimeter. These results suggest that CY administration, depending on the dose and time span, can act as a protective agent against neuronal losses.  相似文献   
30.
AIM: To develop a Home Care Quality Assessment Index (HCQAI) that may be used for overall assessment of home care in three areas: 1) conditions of the impaired elderly (outcome); 2) caregiver and caregiving situation (process); and 3) the home care environment (input). METHODS: To develop the HCQAI, a list of items for assessment was drawn up, and the reliability of each item was verified. Reliability was investigated by a) test-retest reliability, and b) inter-rater reliability. Impaired elderly and their family caregivers who used the visiting nurse station of the Okazaki Medical Association were surveyed. A kappa coefficient of 0.4 or greater generally served as the inclusion criteria for test-retest and inter-rater reliability of each item. A factor analysis was conducted for items satisfying the above criteria, using 10 scales. RESULTS: Cronbach's alpha showing internal consistency (reliability) for these scales was 0.6-0.9. Two scales corresponded to care within the home: the "barrier-free" and "improvement of water facilities"; three to the caregiver situation: "dressing appropriate for the season," "mistreatment by the elderly," and "hygiene and assistance"; and five involved conditions of the impaired elderly: "cognition," "paralysis," "vision and hearing," "ADL," and "gross motor." CONCLUSION: The HCQAI developed in the present study, consisting of 41 items, can assess quality of home care both objectively and comprehensively, based on professional staff observation. Few indexes of this kind exist worldwide to scientifically assess input, process and outcome in the delivery of quality home care for the impaired elderly.  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