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   12852篇
  免费   941篇
  国内免费   40篇
耳鼻咽喉   79篇
儿科学   461篇
妇产科学   406篇
基础医学   1743篇
口腔科学   189篇
临床医学   1534篇
内科学   2647篇
皮肤病学   413篇
神经病学   1289篇
特种医学   281篇
外科学   1082篇
综合类   92篇
一般理论   10篇
预防医学   1583篇
眼科学   249篇
药学   797篇
  1篇
中国医学   26篇
肿瘤学   951篇
  2024年   17篇
  2023年   152篇
  2022年   297篇
  2021年   576篇
  2020年   328篇
  2019年   487篇
  2018年   529篇
  2017年   369篇
  2016年   328篇
  2015年   371篇
  2014年   521篇
  2013年   758篇
  2012年   1055篇
  2011年   1082篇
  2010年   561篇
  2009年   507篇
  2008年   795篇
  2007年   851篇
  2006年   755篇
  2005年   700篇
  2004年   637篇
  2003年   597篇
  2002年   451篇
  2001年   88篇
  2000年   73篇
  1999年   83篇
  1998年   85篇
  1997年   63篇
  1996年   61篇
  1995年   54篇
  1994年   39篇
  1993年   40篇
  1992年   34篇
  1991年   25篇
  1990年   38篇
  1989年   29篇
  1988年   27篇
  1987年   22篇
  1986年   15篇
  1985年   23篇
  1984年   25篇
  1983年   28篇
  1982年   33篇
  1981年   20篇
  1980年   21篇
  1979年   25篇
  1978年   29篇
  1977年   18篇
  1973年   21篇
  1971年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The immunohistochemical detection of six markers of breast cancer has been compared in the present study with known prognostic factors of the disease to establish locally a standard panel of markers for the management of breast cancer. Sections of tissue of 114 consecutive breast cancer cases were studied immunohistochemically, using antibodies against oestrogen receptor (ER), progesterone receptor (PR), androgen receptor, c-erbB2, cathepsin D, and cyclin D. Marker labelling was graded as recommended in the literature. Using the chi(2)-test, relationships were determined between marker labelling and histological type of cancer, tumour grade, tumour size, axillary lymph node status and age of patient. A p value below 0.05 was considered significant. A positive relationship was found between ER and PR and lower grades of cancer, and a negative relationship was found with medullary and atypical medullary carcinoma. The four other markers showed no relationship with grade or type of cancer. All markers showed no significant relationship with size of tumour, presence of axillary node metastasis or age of patient. There was positive correlation between c-erbB2 and cathepsin D. Our study confirms the association between ER and PR and histological type and grade of breast cancer, both known parameters of good prognosis. We found no consistent relationship between the other four markers and prognostic factors studied, other than the suggestion that c-erbB2 and cathepsin D may be useful markers for poor prognosis and can be usefully applied locally, especially in the light of the current availability of trastuzumab (Herceptin) for management of c-erbB2-positive cases. We found no relationship between the markers and tumour size, axillary lymph node status or age.  相似文献   
102.
We describe an adult male with severe learning disability, epilepsy, and dysmorphic features. Cytogenetic studies demonstrated a terminal duplication of the long arm of chromosome 17, resulting in partial trisomy 17q24-q25. Our patient shows some of the characteristic features of the distal 17q phenotype, but in addition has more unusual features such as epilepsy, sensorineural hearing loss, and long fingers and overlapping toes. We suggest that these features occur with terminal duplications of 17q.  相似文献   
103.
Ticks are ectoparasites of wild and domestic animals and humans, and are considered to be the most important arthropod vector of pathogens in North America. Development of vaccines directed against tick proteins may effect reduction of tick infestations and transmission of tick-borne pathogens. The limiting step for the development of tick vaccines has been the identification of tick protective antigens. Reverse vaccinology approaches aimed at reducing animal experimentation while allowing for the rapid screening of pools of potential tick vaccine candidates would greatly facilitate progress towards the development of tick vaccines. Herein, we describe the screening of Ixodes scapularis cDNAs for identification of tick protective antigens using RNA interference (RNAi). The results of the RNAi screening were similar to those obtained previously using expression library immunization and demonstrated that RNAi could serve as a more rapid and cost-effective tool for vaccine antigen discovery in ticks and in other nonmodel organisms.  相似文献   
104.
Stress, coping, and hepatitis B antibody status   总被引:4,自引:0,他引:4  
OBJECTIVE: The present study investigated the association between exposure to stressful life events, coping style, and antibody status after hepatitis B vaccination. METHODS: Two hundred sixty medical school undergraduates, who had received the three-dose hepatitis B vaccine before recruitment to this study, completed questionnaires measuring exposure to stressful life events during the past year, customary coping strategies, and health behaviors. Antibodies against hepatitis B surface antigen were determined; levels <100 mIU/ml were deemed inadequate. RESULTS: Two participant cohorts were identified: those vaccinated within the last year and those vaccinated earlier. In the early vaccination cohort, participants with greater-than-average stress exposures had a more than two-fold increased risk of having an inadequate antibody titer. Coping by accepting the reality of stressful situations proved protective, whereas coping by substance use increased the risk of having an inadequate antibody count in this cohort. These associations remained significant after adjustment for possible mediators. Furthermore, the effects of stress and coping were largely independent of one another. Neither stress nor coping was significantly associated with antibody status in the recently vaccinated cohort. CONCLUSIONS: The present study confirms that the immune system is sensitive to variations in psychological factors. Stressful life events and coping strategy seem to have a continuing impact on hepatitis B antibody status.  相似文献   
105.
The ultrastructural arrangement of Kell (K1) and Cellano (K2) antigens on red cells was studied using ferritin-conjugated rabbit antihuman IgG to stain ghosts derived from antibody-sensitized intact red cells. Estimates of the number of sites under equilibrium binding were obtained by counting both ferritin grains and ferritin clusters on electron micrographs. Values for Kell sites on heterozygous red cells ranged from 2300 to 5900 and for Cellano sites from 2000 to 5000 with no discernible dosage effects. Both the Kell and Cellano antigens were clustered, which was due to conjugate staining of the ghost membranes and does not reflect the topological arrangement of these antigens on the native membrane. The ferritin grain patterns found with the Kell and Cellano antigens was similar to those observed with the Rh antigens except for the markedly reduced antigen site density.  相似文献   
106.
The aim of this study is to investigate the association between three polymorphisms of the interleukin-1 (IL-1) gene complex and schizophrenia. We genotyped 228 outpatients with schizophrenia (DSM-IV criteria) and 419 unrelated healthy controls. The following polymorphisms were analyzed: IL-1alpha -889 C/T, IL-1beta +3953 C/T, and IL-1RA (86 bp)n. No significant differences in genotype or in allelic distribution of the Il-1alpha, IL-1beta, and IL-1RA polymorphisms were found. Estimated haplotype frequencies were similar in both groups. Our data do not suggest that genetically determined changes in the IL-1 gene complex confer increased susceptibility for schizophrenia.  相似文献   
107.
BACKGROUND: There are wide global variations in the prevalence of asthma and wheezing. OBJECTIVES: We examined the associations of place of birth with doctor-diagnosed asthma, wheezing in the past 12 months, and other allergic conditions in Mexican American children. METHODS: The study used data on 4121 Mexican American children age 2 months to 16 years who participated in the Third National Health and Nutrition Examination Survey. RESULTS: The risk of asthma was associated with being born in the United States after adjusting for sex, age, history of ear infection, and having a regular place for health care (odds ratio, 2.19; 95% CI, 1.09-4.40). Among children with no previous history of ear infection, US-born children were more likely to report wheezing in the past 12 months than their peers born in Mexico after controlling for confounding variables (odds ratio, 2.05; 95% CI, 1.09-3.87). Mexican American children born in the United States were more likely to have positive skin reaction to cat, house mite, Alternaria alternata , peanut, Bermuda grass, and short ragweed but were less likely to have a positive skin test to German cockroaches after adjusting for sex, age, ear infection, having a regular place for health care, and area of residence. CONCLUSION: Our study indicated significant associations of place of birth with respiratory symptoms and allergic conditions in Mexican American children. These findings highlight the need for further studies to examine environmental factors that change by migration and explain the observed differential in the risk of asthma or wheezing.  相似文献   
108.
Quality of Life Research - This study examined the clinical utility of post-traumatic stress disorder (PTSD), low resilience, poor sleep, and lifetime blast exposure as risk factors for predicting...  相似文献   
109.
Maternal and Child Health Journal - The Maternal and Child Health (MCH) Pipeline Training Program, promotes development of a diverse health workforce by training undergraduate students from...  相似文献   
110.
Advances in Health Sciences Education - Critical reflection supports enactment of the social roles of care, like collaboration and advocacy. We require evidence that links critical teaching...  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