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   41697篇
  免费   2874篇
  国内免费   161篇
耳鼻咽喉   502篇
儿科学   1347篇
妇产科学   553篇
基础医学   4999篇
口腔科学   532篇
临床医学   4316篇
内科学   9237篇
皮肤病学   703篇
神经病学   3946篇
特种医学   1669篇
外科学   7265篇
综合类   360篇
一般理论   81篇
预防医学   3142篇
眼科学   1155篇
药学   2199篇
中国医学   39篇
肿瘤学   2687篇
  2024年   32篇
  2023年   401篇
  2022年   687篇
  2021年   1566篇
  2020年   773篇
  2019年   1288篇
  2018年   1559篇
  2017年   1067篇
  2016年   1172篇
  2015年   1255篇
  2014年   1754篇
  2013年   2075篇
  2012年   3490篇
  2011年   3484篇
  2010年   1898篇
  2009年   1688篇
  2008年   2814篇
  2007年   2753篇
  2006年   2662篇
  2005年   2508篇
  2004年   2447篇
  2003年   2053篇
  2002年   1892篇
  2001年   247篇
  2000年   180篇
  1999年   253篇
  1998年   362篇
  1997年   316篇
  1996年   234篇
  1995年   222篇
  1994年   168篇
  1993年   164篇
  1992年   116篇
  1991年   113篇
  1990年   82篇
  1989年   70篇
  1988年   51篇
  1987年   62篇
  1986年   60篇
  1985年   59篇
  1984年   75篇
  1983年   83篇
  1982年   102篇
  1981年   76篇
  1980年   52篇
  1979年   26篇
  1978年   32篇
  1977年   34篇
  1976年   20篇
  1973年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Ninety-seven inpatients with tardive dyskinesia (average AIMS score = 13), the majority of whom were schizophrenic, were studied. Forty patients were Caucasian, and 57 were African-American. The APOE genotypes of these patients were compared to previously published genotypes of controls and with previously published studies of APOE genotypes in patients with schizophrenia. There were no significant differences in APOE allele frequencies comparing the African-American tardive dyskinesia population and the African-American control groups. In contrast, significant (< 0.05) P values were obtained comparing the Caucasian tardive dyskinesia population to the Caucasian controls, when comparing allele frequencies and genotypic frequencies. This study suggests that Caucasians bearing an APOE2 allele are at increased risk of developing tardive dyskinesia, whereas African-Americans are not. APOE genotype-specific risks of both tardive dyskinesia and Alzheimer's disease that vary across populations could be due to recruitment of patients or controls or could be due to modifying effects of differing genetic or environmental backgrounds. The mechanism by which the APOE2 allele increases risk of tardive dyskinesia is not known. Further information about the mechanisms of increased risk of tardive dyskinesia could result in stratification of prescribing practices weighing the costs of medications against the relative risk of side effects.  相似文献   
2.
This study examined the feasibility of isolating and transferringthe centrosome-containing region of spermatozoa to mature humanoocytes. The findings demonstrate that individual sperm centrosomescan be transferred and are capable of nucleating maternal tubulinto form a well-developed sperm aster in the recipient oocyte.The results are discussed with respect to centrosome functionin early human development and applications in clinical in-vitrofertilization in the treatment of certain forms of male factorinfertility.  相似文献   
3.
4.
Laboratory routines cause animal stress.   总被引:8,自引:0,他引:8  
Eighty published studies were appraised to document the potential stress associated with three routine laboratory procedures commonly performed on animals: handling, blood collection, and orogastric gavage. We defined handling as any non-invasive manipulation occurring as part of routine husbandry, including lifting an animal and cleaning or moving an animal's cage. Significant changes in physiologic parameters correlated with stress (e.g., serum or plasma concentrations of corticosterone, glucose, growth hormone or prolactin, heart rate, blood pressure, and behavior) were associated with all three procedures in multiple species in the studies we examined. The results of these studies demonstrated that animals responded with rapid, pronounced, and statistically significant elevations in stress-related responses for each of the procedures, although handling elicited variable alterations in immune system responses. Changes from baseline or control measures typically ranged from 20% to 100% or more and lasted at least 30 min or longer. We interpret these findings to indicate that laboratory routines are associated with stress, and that animals do not readily habituate to them. The data suggest that significant fear, stress, and possibly distress are predictable consequences of routine laboratory procedures, and that these phenomena have substantial scientific and humane implications for the use of animals in laboratory research.  相似文献   
5.
Fiber-reinforced resin composites (FRCs) have been used to make frameworks to support particulate resin composite veneers in the replacement of missing teeth. Both prosthetic laboratory-fabricated and chairside-fabricated approaches have been used with varying degrees of success. The chairside FRC fixed partial denture has been mainly used for anterior tooth replacement where the emphasis is on esthetics rather than withstanding occlusal load. This article focuses on the use of this technology in the chairside replacement of premolars. The concept of using a prefabricated framework is described in detail. This approach allows for the efficient delivery of a consistently made chairside prosthesis. This is in contrast with the time-consuming and less consistent result of FRC framework fabrication directly in the mouth. The goal for this concept is to use a premade framework finalized by the provider at chairside to provide medium- to long-term posterior tooth replacement, with minimal abutment tooth reduction.  相似文献   
6.
OBJECTIVE: This study's objective was to assess knowledge of phosphorus compared with other nutrients in patients undergoing maintenance dialysis (MD). DESIGN: We compared knowledge of phosphorus vs. other nutrients important to the MD diet (potassium, sodium, and protein) in patients undergoing hemodialysis (HD) and peritoneal dialysis (PD). We further measured gender, age, education level, and functional health literacy to assess correlations in patient nutrient knowledge. Nutrient knowledge was measured using a 25-item Chronic Kidney Disease Knowledge Assessment Tool for Nutrition (CKDKAT-N), and functional health literacy was measured using the short form of the Test of Functional Health Literacy in Adults (S-TOFHLA). SETTING AND PATIENTS: Patients received maintenance outpatient PD or HD at Wisconsin Dialysis, Inc. (Madison, WI). MAIN OUTCOME MEASURE: The main outcome measure was knowledge of phosphorus vs. knowledge of potassium, sodium, and protein. RESULTS: Forty-seven MD patients participated in the study (29 undergoing HD, 18 undergoing PD, 30 males, 17 females, average age of 58.6 (SD, 13.8) years, and average grade level of 1.4 (SD, 2.6) years of post-secondary education). Thirty-five participants had adequate health literacy, 4 had marginal health literacy, and 8 had inadequate health literacy. The CKDKAT-N scores ranged from 6-21 for 25 items, with a mean score of 13 (SD, 2.91). Knowledge of phosphorus compared with knowledge of other nutrients was poor (0.38 vs. 0.72, P = .003). In a comparison of HD vs. PD patient knowledge, both phosphorus (0.37 vs. 0.42, P = .231) and other nutrients (0.69 vs. 0.80, P = .115) were the same. CONCLUSION: Despite regular dietary instruction, patients undergoing MD have a poor knowledge of dietary phosphorus content, compared with knowledge of other nutrients important in chronic kidney disease. Interestingly, there was no difference in nutrition knowledge when comparing PD and HD patients, despite differences in education level and health literacy between groups.  相似文献   
7.
8.
9.
10.
Assessment of quality of life in children with peanut allergy   总被引:5,自引:0,他引:5  
Children with a peanut allergy (PA) are faced with food and social restrictions due to the potentially life-threatening nature of their disease, for which there is no cure or treatment. This inevitably impacts upon their quality of life (QoL). QoL of 20 children with PA and 20 children with insulin-dependent diabetes mellitus (IDDM) was measured using two disease-specific QoL questionnaires (higher scores correspond to a poorer QoL). One questionnaire was designed by us and the other was adapted from the Vespid Allergy QoL questionnaire. We gave subjects cameras to record how their QoL is affected over a 24-h period. Response rates for both questionnaires were 100%. Mean ages were 9.0 and 10.4 years for PA and IDDM subjects, respectively. Children with a PA reported a poorer quality of life than children with IDDM: mean scores were 54.85 for PA subjects and 46.40 for diabetics (p = 0.004) in questionnaire 1 and 54.30 and 34.50 (p≤0.001) in questionnaire 2. PA children reported more fear of an adverse event and more anxiety about eating, especially when eating away from home. Photographs fell into seven common categories: food, management, environment, away from home, physical activities, restaurant and people. Most photographs related to food and management issues and revealed difficulties for both groups regarding food restrictions. PA subjects felt more threatened by potential hazards within their environment, felt more restricted by their PA regarding physical activities, and worried more about being away from home. However, they felt safe when carrying epinephrine kits and were positive about eating at familiar restaurants. The QoL in children with PA is more impaired than in children with IDDM. Their anxiety may be considered useful in some situations, promoting better adherence to allergen avoidance advice and rescue plans.  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