全文获取类型
收费全文 | 14626篇 |
免费 | 963篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 415篇 |
妇产科学 | 396篇 |
基础医学 | 1717篇 |
口腔科学 | 179篇 |
临床医学 | 2249篇 |
内科学 | 2995篇 |
皮肤病学 | 179篇 |
神经病学 | 1412篇 |
特种医学 | 249篇 |
外科学 | 1410篇 |
综合类 | 387篇 |
一般理论 | 18篇 |
预防医学 | 2029篇 |
眼科学 | 262篇 |
药学 | 635篇 |
中国医学 | 15篇 |
肿瘤学 | 1014篇 |
出版年
2023年 | 73篇 |
2022年 | 81篇 |
2021年 | 265篇 |
2020年 | 152篇 |
2019年 | 243篇 |
2018年 | 289篇 |
2017年 | 217篇 |
2016年 | 231篇 |
2015年 | 294篇 |
2014年 | 435篇 |
2013年 | 700篇 |
2012年 | 981篇 |
2011年 | 1137篇 |
2010年 | 604篇 |
2009年 | 530篇 |
2008年 | 1010篇 |
2007年 | 1062篇 |
2006年 | 1014篇 |
2005年 | 1007篇 |
2004年 | 980篇 |
2003年 | 890篇 |
2002年 | 840篇 |
2001年 | 123篇 |
2000年 | 111篇 |
1999年 | 149篇 |
1998年 | 210篇 |
1997年 | 151篇 |
1996年 | 132篇 |
1995年 | 122篇 |
1994年 | 105篇 |
1993年 | 94篇 |
1992年 | 74篇 |
1991年 | 62篇 |
1990年 | 65篇 |
1989年 | 71篇 |
1988年 | 62篇 |
1987年 | 50篇 |
1986年 | 53篇 |
1985年 | 53篇 |
1984年 | 66篇 |
1983年 | 81篇 |
1982年 | 73篇 |
1981年 | 77篇 |
1980年 | 63篇 |
1979年 | 48篇 |
1978年 | 52篇 |
1977年 | 43篇 |
1976年 | 37篇 |
1975年 | 31篇 |
1974年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
171.
A Competency-based Model of Child Depression: A Longitudinal Study of Peer, Parent, Teacher, and Self-evaluations 总被引:8,自引:0,他引:8
David A. Cole Joan M. Martin Bruce Powers 《Journal of child psychology and psychiatry, and allied disciplines》1997,38(5):505-514
In a two-wave longitudinal study of third and sixth graders ( N = 617), we obtained self-reports of depression and peer, teacher, parent, and self-reports of competence in five domains: academic, social, attractiveness, conduct, and athletic. Competency evaluations by others predicted change in self-perceived competence over time for girls, but not for boys. Depression predicted change in self-perceived competence over time for boys but not for girls. Among girls, the relative importance of parent, teacher, and peer appraisals shifted from third to sixth grade. For both boys and girls, self-perceptions of competence predicted change in depression scores over time. Furthermore, self-perceived competencies mediated the relation between competency appraisals by others and children's self-reported depression. Results are interpreted in light of a competency-based model of child depression. 相似文献
172.
Joan C. Engebretson RN DrPH Diane Wind Wardell RNC PhD 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1997,26(6):660-664
Nonnutritive sucking can provide low-birth-weight infants with an opportunity to organize their behavior, an important component of developmental care. A pacifier specifically designed for low-birth-weight infants facilitates their nonnutritive sucking to more fully meet their needs. The research and development of a pacifier for low-birth-weight infants incorporated a naturalistic approach and used the best model, the infant thumb, in the design. Clinical trials with infants randomized to control and experimental groups were conducted to compare the prototype pacifier to a commercially available pacifier. Observations using the Anderson Behavioral State Scale demonstrated that infants using the prototype pacifier more often were found to be in an alert state. This pacifier may contribute to infants' state organization for optimum feeding and could be a component in developmental care planning. 相似文献
173.
Bernard F. Fuemmeler Larry L. Mullins Jill Van Pelt Melissa Y. Carpentier Joan Parkhurst 《Children's Health Care》2005,34(4):289-303
In this study, we compared levels of posttraumatic stress symptoms (PTSS) and general psychological distress between parents of childhood cancer survivors and parents of children with Type 1 diabetes mellitus (DM1). In this study, we also examined potential risk factors for PTSS. Participants included 47 parents of childhood cancer survivors and 31 parents of children with DM1. Participants completed self-report measures of posttraumatic stress, general psychological distress, coping strategies, social network size, and perceived illness uncertainty. Findings revealed that parents of children surviving cancer reported higher levels of PTSS and general distress than parents of children with DM1. In the total sample, lower levels of emotion-focused coping and greater perceived uncertainty were associated with increased frequency of both PTSS and general psychological distress after we accounted for demographic and illness variables. Having a child with cancer may increase the risk for experiencing PTSS. Interventions are warranted that focus specifically on the reduction of PTSS in parents of children surviving cancer. 相似文献
174.
Janie Canty-Mitchell Joan K. Austin Susan M. Perkins Rong Amy Qi Nancy Swigonski 《Children's Health Care》2005,34(1):1-18
Our objective was to examine health-related quality of life (HRQOL) in publicly insured children with special health care needs (CSHCN). Data were obtained from 183 caregivers of CSHCN (M = 10 years; 54% African American) in urban health clinics. CSHCN had poorer physical and psychosocial HRQOL than children in a normative sample. In regression analysis, children who had more health problems and more health visits in the previous 12 months had poorer physical HRQOL. Poorer psychosocial HRQOL was associated with more health problems and urban life stressors. Implications for practice and policy are discussed. 相似文献
175.
176.
Marc-Oliver Wright Eli N Perencevich Christopher Novak Joan N Hebden Harold C Standiford Anthony D Harris 《Infection control and hospital epidemiology》2004,25(4):325-332
BACKGROUND AND OBJECTIVE: Rapid identification and investigation of potential outbreaks is key to limiting transmission in the healthcare setting. Manual review of laboratory results remains a cumbersome, time-consuming task for infection control practitioners (ICPs). Computer-automated techniques have shown promise for improving the efficiency and accuracy of surveillance. We examined the use of automated control charts, provided by an automated surveillance system, for detection of potential outbreaks. SETTING: A 656-bed academic medical center. METHODS: We retrospectively reviewed 13 months (November 2001 through November 2002) of laboratory-patient data, comparing an automated surveillance application with standard infection control practices. We evaluated positive predictive value, sensitivity, and time required to investigate the alerts. An ICP created 75 control charts. A standardized case investigation form was developed to evaluate each alert for the likelihood of nosocomial transmission based on temporal and spatial overlap and culture results. RESULTS: The 75 control charts were created in 75 minutes and 18 alerts fired above the 3-sigma level. These were independently reviewed by an ICP and associate hospital epidemiologist. The review process required an average of 20 minutes per alert and the kappa score between the reviewers was 0.82. Eleven of the 18 alerts were determined to be potential outbreaks, yielding a positive predictive value of 0.61. Routine surveillance identified 5 of these 11 alerts during this time period. CONCLUSION: Automated surveillance with user-definable control charts for cluster identification was more sensitive than routine methods and is capable of operating with high specificity and positive predictive value in a time-efficient manner. 相似文献
177.
Distinctive gene expression profiles by cDNA microarrays in endometrioid and serous carcinomas of the endometrium. 总被引:2,自引:0,他引:2
Q Jackie Cao Thomas Belbin Nicholas Socci Raluca Balan Michael B Prystowsky Geoffrey Childs Joan G Jones 《International journal of gynecological pathology》2004,23(4):321-329
Endometrial carcinomas are classified by their morphology into two major subtypes. Endometrioid carcinomas (type I) are generally estrogen dependent, well-differentiated, superficially invasive, and have a good outcome. Serous carcinomas (type II) are hormone independent, frequently deeply invasive and widely metastatic, and have a poor prognosis. Microarray technology and analysis allows us to determine if the global gene expression profiles of these two subtypes correlate with their morphologic phenotype. Fresh tissue from 18 endometrial carcinomas was studied: 7 well-, 2 moderately, and one poorly differentiated endometrioid, 4 serous carcinomas, and 4 high-grade mixed endometrioid-serous carcinomas. Labeled cDNA probes were synthesized (Cy5 for tumor, Cy3 for reference) and applied to microarrays containing 18,098 cDNA clones or ESTs. A pool of equal amounts of total RNA from each tumor served as the reference RNA. By unsupervised cluster analysis, the endometrioid carcinomas clustered together and were separate from the serous carcinomas. The high-grade mixed carcinomas clustered with the serous carcinomas. Using a statistical algorithm based on gene expression pattern and conducting a supervised analysis of the two defined groups, we have identified 315 genes that statistically differentiate type I from type II endometrial carcinomas. In addition to corroborating the predicted overexpression of known markers (e.g., ras and catenin in endometrioid carcinomas), the cDNA microarray technique has revealed novel alterations in gene expression relevant to cell cycle, cell adhesion, signal transduction, apoptosis, and tumor progression not previously implicated in endometrial carcinomas. For serous carcinomas, these include aldolase, desmoplakin, integrin-linked kinase, PKC, and metallopeptidase. In conclusion, the gene expression profiles of type I and type II endometrial carcinomas are different. Refinement of these profiles will permit more accurate diagnostic tumor classification and the development of prognosis assays. 相似文献
178.
179.
180.