全文获取类型
收费全文 | 40271篇 |
免费 | 2518篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 410篇 |
儿科学 | 1325篇 |
妇产科学 | 1044篇 |
基础医学 | 5356篇 |
口腔科学 | 644篇 |
临床医学 | 6409篇 |
内科学 | 7329篇 |
皮肤病学 | 629篇 |
神经病学 | 4056篇 |
特种医学 | 799篇 |
外科学 | 3677篇 |
综合类 | 515篇 |
一般理论 | 57篇 |
预防医学 | 4994篇 |
眼科学 | 494篇 |
药学 | 2380篇 |
2篇 | |
中国医学 | 68篇 |
肿瘤学 | 2718篇 |
出版年
2023年 | 213篇 |
2022年 | 406篇 |
2021年 | 837篇 |
2020年 | 513篇 |
2019年 | 861篇 |
2018年 | 998篇 |
2017年 | 694篇 |
2016年 | 713篇 |
2015年 | 920篇 |
2014年 | 1266篇 |
2013年 | 1937篇 |
2012年 | 2858篇 |
2011年 | 3034篇 |
2010年 | 1668篇 |
2009年 | 1405篇 |
2008年 | 2735篇 |
2007年 | 2743篇 |
2006年 | 2771篇 |
2005年 | 2557篇 |
2004年 | 2467篇 |
2003年 | 2371篇 |
2002年 | 2203篇 |
2001年 | 368篇 |
2000年 | 283篇 |
1999年 | 421篇 |
1998年 | 460篇 |
1997年 | 408篇 |
1996年 | 361篇 |
1995年 | 319篇 |
1994年 | 301篇 |
1993年 | 287篇 |
1992年 | 254篇 |
1991年 | 206篇 |
1990年 | 213篇 |
1989年 | 189篇 |
1988年 | 157篇 |
1987年 | 172篇 |
1986年 | 149篇 |
1985年 | 156篇 |
1984年 | 198篇 |
1983年 | 223篇 |
1982年 | 212篇 |
1981年 | 195篇 |
1980年 | 177篇 |
1979年 | 121篇 |
1978年 | 93篇 |
1977年 | 108篇 |
1976年 | 72篇 |
1975年 | 74篇 |
1974年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Michael F Parry Brenda Grant Anthony Iton Patricia D Parry Diane Baranowsky 《Infection control and hospital epidemiology》2004,25(11):929-932
BACKGROUND: The need to improve influenza vaccination delivery in our community became painfully clear during the winter of 1997-1998 when high rates of respiratory illness led to congestion in the emergency department and a critical shortage of hospital beds. In response, the local hospital and the Department of Health launched a collaborative program to increase influenza vaccine coverage in the community. METHODS: The partnership was designed to increase the number of citizens receiving influenza vaccine and to moderate the severity of lower respiratory tract illness during the winter season. A variety of methods were used to increase public awareness, enhance vaccine delivery, and create a relatively seamless service for the community. RESULTS: During three seasons, influenza vaccination rates increased by a relative 150%. This represented immunization of 16% of the entire community and more than 75% of residents older than 65 years. Hospital employee vaccination rates also rose from 34% to 58%. When compared with other hospitals in the county, the campaign reduced the average number of annual visits to the emergency department for all respiratory diagnoses by 34% and exacerbations of chronic obstructive pulmonary disease by 46%. CONCLUSIONS: This influenza vaccination program illustrates the potential for synergy that exists between local departments of health and community hospitals in successfully increasing vaccine delivery to the community. Furthermore, it also suggests that such efforts can be successful in reducing use of the emergency department, resulting in a positive impact on the health of the community. 相似文献
82.
Theresa B Haddy Revonda B Mosher Patricia A Dinndorf Gregory H Reaman 《The Journal of adolescent health》2004,34(4):324-329
PURPOSE: To estimate the incidence and types of second neoplasms in survivors of childhood and adolescent cancer, as well as the characteristics of those who developed second neoplasms. METHODS: Survivors who were under age 21 years at initial diagnosis, off therapy, and in remission for 2 years are referred to the Long Term Survivors' Clinic (LTSC) at Children's National Medical Center (CNMC). This review includes patients entered in the clinic database from January 1, 1997 to August 30, 2002. RESULTS: Twenty-three (2.3%) of 987 childhood cancer survivors followed in the LTSC had 26 (2.6%) second and third neoplasms. The mean age was 6.7 years at initial diagnosis, 20.3 years at diagnosis of the second neoplasm, and 20.5 years at diagnosis of the third neoplasm. Of 10 female and 13 male patients, 15 were white, six black, one Hispanic, and one Asian. All but two of the patients received radiation. Nineteen neoplasms, including seven thyroid carcinomas, six central nervous system tumors (three meningiomas), three basal cell carcinomas, two breast cancers, and one soft tissue sarcoma, occurred at sites within or contiguous to radiation sites. Five patients died, but the majority of neoplasms were treatable and most patients had good outcomes. CONCLUSION: Indefinite follow-up in a long-term survivors' clinic is indicated for adolescent and adult survivors of childhood cancer, with routine examination and screening for recurrence of the initial cancer as well as late effects, including second neoplasms. 相似文献
83.
84.
85.
Timothy J Beebe Stephen E Asche Patricia A Harrison Kathryn B Quinlan 《The Journal of adolescent health》2004,35(2):116-123
PURPOSE: To profile adolescent Internet chat room users in terms of demographic characteristics, psychological and environmental factors, and behavioral risk factors. METHODS: The study sample was drawn from respondents to an anonymous statewide survey of 50,168 9th-grade public school students and included 40,376 students who reported Internet access at home and 19,511 who accessed chat rooms. Data were collected by the Minnesota Student Survey (MSS), a survey that has been administered triennially by the state's education department to public school students in grades 6, 9, and 12 since 1989. The MSS includes more than 117 questions (300 variables) addressing attitudinal, behavioral, and environmental issues. Data analysis consisted of comparing the odds of a particular characteristic or behavior for chat room users with that of nonusers. Analyses were run separately for boys and girls. The homogeneity of odd ratios was tested with the Breslow-Day statistic using SPSS for Windows. RESULTS: For boys and girls, use of Internet chat rooms was associated with psychological distress, a difficult living environment, and a higher likelihood of risky behaviors. Although most chat room users did not report serious problems, this group included a disproportionate number of troubled individuals. CONCLUSIONS: Because chat room use serves as an indicator of heightened vulnerability and risk-taking, parents and others need to be aware of potential dangers posed by online contact between strangers and youth. 相似文献
86.
87.
Patricia A. Ludowyk David O. Willenborg Christopher R. Parish 《Journal of neuroimmunology》1992,37(3):237-250
Using experimental autoimmune encephalomyelitis (EAE) in the rat as a model of central nervous system (CNS) inflammation, activated and quiescent T lymphocytes with different antigen specificities were labelled with the fluorescent dye Hoechst 33342 and tested by fluorescence microscopy for their ability to accumulate in different regions of the spinal cord and in other organs at varying times post inoculation. With this highly sensitive assay it was found that activated myelin basic protein (MBP)-specific T cell lines accumulated in the spinal cord (a 1000-fold increase in the lumbar/sacral region by day 4) and caused clinical signs of EAE. In contrast, interleukin-2 (IL-2)-maintained (quiescent) MBP-specific T cell lines failed to accumulate in the CNS and cause disease. Activated ovalbumin (OA)-specific and purified protein derivative of tuberculin (PPD)-specific T cell lines were also found at significantly higher levels in the spinal cord than non-activated cells although they failed to accumulate to a substantial degree when injected alone. When injected with activated MBP-specific T cells the activated OA- and PPD-specific cell lines accumulated in the spinal cord following initial accumulation of the MBP-specific cells, demonstrating that during the inflammatory process there is considerable non-specific recruitment of cells into the inflammatory site. CNS accumulation of activated MBP-specific T cell lines occurred 1-2 days later in irradiated animals than in non-irradiated recipients. This was consistent with irradiated animals also exhibiting a later onset of disease and suggests that irradiation may directly affect the endothelium in a way that makes it less adhesive. In conclusion, this study demonstrates that activated lymphocytes of any specificity enter the spinal cord, and that the neuro-antigen specific cells accumulate there and lead to the recruitment of other cells. Non-activated cells, even those with neural antigen specificity fail to enter the cord. Understanding the nature of what an 'activated' lymphocyte is may allow us to design strategies to inhibit such immune-mediated inflammation. 相似文献
88.
Susan R. Gartner Catherine L. Gilliss Julie A. Shinn Patricia A. Sparacino Sally Rankin Maribelle Leavitt Martha Price Mark Hudes 《Journal of advanced nursing》1988,13(5):649-661
To enhance individual and family health during recovery from heart surgery, this study employed nursing interventions based on self-efficacy and family stress theory during the hospitalization period and for 3 months thereafter. The effectiveness of the interventions were assessed through a randomized trial in which 67 prospective bypass and valve surgery patients, aged 30-77 years, and their spouses, were allocated either the experimental interventions or usual care and followed for 6 months. At 3 months post-surgery, the only statistically significant differences between the experimentals and controls were on perceived self-efficacy for lifting and tolerating emotional distress. At 6 months no significant differences were found on individual or family measures. Analyses revealed that age, gender and preoperative cardiac status significantly affected individual recovery. The study is continuing with a larger sample in order to explicate the recovery process and to better determine whether a low intensity nursing intervention can effect changes in individual and family recovery. 相似文献
89.
Patricia Aikins Murphy Jane Mashburn Barbara W. Graves Mickey Gillmor-Kahn 《Journal of Midwifery & Women's Health》1992,37(6):404-410
This article reviews the normal hematologic changes in pregnancy and the kinetics of iron metabolism. The differences between iron depletion and anemia are described. The hematocrit levels of a nurse-midwifery caseload in a tertiary-care setting are described and compared with recently published population norms. Hematocrits of the sample compared favorably to the population hematocrits until 24 weeks' gestation, when the sample hematocrit mean became statistically lower and remained that way throughout pregnancy. Further analysis was done on the sample hematocrits, comparing differences in parity, age, pregnancy spacing, and AS versus AA hemoglobin. Parous women with a pregnancy interval >12 months had a higher mean hematocrit then nulliparous women. Mean hematocrits of age groups varied significantly only at the 29–32-week interval, with women younger than 18 having lower mean hematocrits than those ≥18. A trend of women with AS hemoglobin having higher hematocrits than women with AA hemoglobin was identified, reaching statistical significance at the 29–32-week interval. 相似文献
90.