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   985篇
  免费   94篇
  国内免费   5篇
耳鼻咽喉   4篇
儿科学   33篇
妇产科学   12篇
基础医学   98篇
口腔科学   16篇
临床医学   96篇
内科学   242篇
皮肤病学   17篇
神经病学   50篇
特种医学   21篇
外科学   156篇
综合类   15篇
现状与发展   1篇
预防医学   149篇
眼科学   4篇
药学   112篇
中国医学   10篇
肿瘤学   48篇
  2023年   17篇
  2022年   58篇
  2021年   62篇
  2020年   42篇
  2019年   33篇
  2018年   50篇
  2017年   34篇
  2016年   39篇
  2015年   41篇
  2014年   41篇
  2013年   38篇
  2012年   72篇
  2011年   69篇
  2010年   29篇
  2009年   34篇
  2008年   42篇
  2007年   38篇
  2006年   38篇
  2005年   32篇
  2004年   30篇
  2003年   38篇
  2002年   27篇
  2001年   19篇
  2000年   25篇
  1999年   18篇
  1998年   7篇
  1997年   4篇
  1996年   3篇
  1995年   4篇
  1994年   2篇
  1993年   5篇
  1992年   10篇
  1991年   7篇
  1990年   9篇
  1989年   7篇
  1988年   4篇
  1987年   5篇
  1986年   10篇
  1985年   8篇
  1984年   6篇
  1983年   4篇
  1982年   2篇
  1981年   3篇
  1980年   3篇
  1979年   3篇
  1978年   7篇
  1977年   1篇
  1974年   2篇
  1973年   1篇
  1971年   1篇
排序方式: 共有1084条查询结果,搜索用时 15 毫秒
61.
OBJECTIVES: To study the phenotype/genotype correlations in Arab patients with familial Mediterranean fever (FMF). PATIENTS AND METHODS: The study was performed in a 3-year period (February 1998-February 2001). Patients were seen in the pediatric FMF clinic of Jordan University Hospital, and the diagnosis of FMF was made according to published criteria. Screening for mutations was carried out by direct sequencing of the entire coding sequence of exon 10 and its donor splice site and by restriction endonuclease testing for mutations in exon 2. A total of 278 patients with clinically positive FMF were screened. RESULTS: Of the 278 patients, 50 (18%) had 2 mutations identified, and 76 (27%) other patients had only 1 mutation identified. The 50 patients with 2 mutations are the subject of this report. The M694V/M694V and the M694V/V726A and M694I/M694I genotypes were the most common (30%, 16%, and 14%, respectively). Three homozygous genotypes (M694V/M694V, V726A/V726A, and M694I/M694I) and 2 compound heterozygous genotypes (M694V/V726A and V726A/M680I) accounted for 78% of mutations. The difference in the mean severity score (14 +/- 2) of the M694V/M694V group and the V726A/V726A (mean severity score, 10 +/- 3) and M694I/M6941 (mean severity score, 6 +/- 1) groups was statistically significant (P =.003 and.0, respectively). The difference between the M649V/M694V group and the M694V/V726A (mean severity score, 15 +/- 2) was not statistically significant (P = 0.31). CONCLUSIONS: The genotypes M694V/M694V and M694V/V726A have a severe clinical course in Arab patients with FMF, whereas the M694I/M694I is associated with mild disease.  相似文献   
62.
63.
Venalot, a mixture of coumarin and troxerutin, in the proportion 1 to 6 respectively, was given orally to baboons at dosages of 0, 100, 300 and 1000 mg/kg/day for 26 weeks. Vomiting, usually within 3 h of administration and considered to be of central origin, in addition to vomiting immediately after dosing, was noted in animals receiving 1000 mg/kg/day. At this level, collapse on several occasions in two animals, one of which died, was also observed. Another animal receiving 1000 mg/kg/day was killed for humane reasons following a period of weight loss, reduced appetite and deterioration in body condition. However, no adverse effect on body weight gain, food or water consumption, ophthalmoscopic or electrocardiographic examinations were noted in any other animals during this study. Increased levels of liver function (serum leucine amino-peptidase (LAP), and serum ornithine carbamyl transferase (OCT) were noted during the dosing period, together with slightly increased liver weights terminally for animals receiving 1000 mg/kg/day; however, as no morphological or ultrastructural changes were noted, these findings were considered to be attributable to hypertrophy.  相似文献   
64.
Three children, ages 6 months, 13 months and 10 years were treated by exchange transfusions following exposure to methylmercury in the Iraq outbreak in 1971-72. Two had severe signs of poisoning and the other was clinically normal but had a high blood mercury concentration. Exchange transfusion resulted in clearance of mercury not only from blood but also from other tissues. The average amount of mercury removed in a two hour exchange was estimated as 6% of the body burden as compared to 1% of the body burden removed by normal excretion processes in 24 hours. No dramatic improvement in the clinical condition of the two poisoned patients occurred. Some improvement in motor power and function was observed during follow-up visits to their houses.  相似文献   
65.
Ryan R  Newnham A  Khunti K  Majeed A 《Public health》2005,119(10):892-899
OBJECTIVE: The objective of this study was to estimate the annual rate of diagnosis of new cases of diabetes mellitus in England and Wales, and the number of new cases in each year. STUDY DESIGN: Cohort study. METHOD: Analysis of electronic patient records from the General Practice Research Database, using 208 general practices with a total list size of 1.3 million patients. RESULTS: We estimate that the national rate of diagnosis of new cases of diabetes in England and Wales was 17.5 [95% confidence intervals (CI) 16.6--18.4] per 10,000 person-years in 1994 and 22.1 (95%CI 21.2--23.0) per 10,000 person-years in 1998. We estimate that there were 87,642 new cases of diabetes mellitus in England and Wales in 1994 and 111,345 in 1998. CONCLUSIONS: We estimate that the rate at which new cases of diabetes were diagnosed rose by about 26% in England and Wales from 1994 to 1998. This conclusion was unchanged when we took account of the ageing of the national populations between the beginning and end of the study period. We estimate that the number of new cases of diabetes diagnosed each year in England and Wales also increased by one-quarter over the same period. If the number of cases and the rate at which they are diagnosed continues to increase, this will need to be considered by those planning services for people with diabetes.  相似文献   
66.
BACKGROUND: This paper aims to compare orphans' development in two different care systems. METHODS: Based on age, sex, psychological trauma scores, competence and psychological problem scores, two comparable samples were found representing orphans in the traditional foster care (n = 94) and the orphanages (n = 48) in a middle-large city in Iraqi Kurdistan. At an index interview, Child Behaviour Checklist (CBCL), Harvard-Uppsala Trauma Questionnaire for Children and Post-traumatic Stress Symptoms for Children (PTSS-C) were administered to the caregivers. After 1 year the CBCL, and after 2 years both the CBCL and the PTSS-C, were-re-administered, consecutively. RESULTS: Although both samples revealed significant decrease in the means of total competence and problem scores over time, the improvement in activity scale, externalizing problem scores and post-traumatic stress disorder-related symptoms proved to be more significant in the foster care than in the orphanages. While the activity scale improved in the foster care, the school competence deteriorated in both samples, particularly among the girls in the orphanages. The improvement of boys' activity scores in the foster care, and deterioration of girls' school competence in the orphanages were the most significant gender differences between samples over time. CONCLUSIONS: Even if the two orphan care systems showed more similarities than differences, the foster care revealed better outcomes over time. The results are discussed in relation to gender, age, socio-economic situation, cultural values and the characteristics of each care system.  相似文献   
67.
68.
Snakebite cases may have myriad presentations. we are describing a previously healthy young man presenting within half an hour of snakebite who experienced abrupt fatal cardiac rhythm changes ranging from bradycardia to ventricular tachycardia/fibrillation over a short span of time.  相似文献   
69.

Background

There are multiple studies in different countries regarding the prevalence of vitamin D deficiency. These studies showed high prevalence of vitamin D deficiency in Asian countries. This study tries to elucidate the prevalence of vitamin D deficiency and its influencing factors in population of Tehran.

Methods

1210 subjects 20–64 years old were randomly selected. 25 (OH) D serum levels were measured. Duration of exposure to sunlight, the type of clothing and level of calcium intake and BMI were quantified based on a questionnaire.

Results

A high percentage of vitamin D deficiency was defined in the study population. Prevalence of severe, moderate and mild Vitamin D deficiency was 9.5%, 57.6% and 14.2% respectively. Vitamin D serum levels had no significant statistical relation with the duration of exposure to sunlight, kind of clothing and BMI. Calcium intake in the normal vitamin D group was significantly higher than the other groups (714.67 ± 330.8 mg/day vs 503.39 ± 303.1, 577.93 ± 304.9,595.84 ± 313.6). Vitamin D serum levels in young and middle aged females were significantly lower than the older group.

Conclusions

Vitamin D deficiency has a high prevalence in Tehran. In order to avoid complications of vitamin D deficiency, supplemental dietary intake seems essential.  相似文献   
70.
METHODS: Primary care organizations (PCOs) in England are required to run a prescribing incentive scheme. The average payment received by general practitioners (GPs) under these schemes is not known. We conducted a longitudinal (2 year) questionnaire study of all PCOs in London and the south east of England aiming to explore the relationship between the financial incentives, the selection of prescribing indicators and success at remaining within budget. In the second year, the average reward per GP amounted to 1220 pounds (range 470 pounds-4330 pounds). Underspent PCOs made larger incentive scheme payments to their practices as did PCOs that had successfully overturned a first year overspend into a second year underspend. The size of rewards was unrelated to the selection of any particular cost- or quality-based prescribing indicator. We conclude that larger prescribing incentive scheme payments may have contributed to prescribing cost control but their effect on prescribing quality is uncertain.  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