全文获取类型
收费全文 | 33784篇 |
免费 | 5992篇 |
国内免费 | 132篇 |
专业分类
耳鼻咽喉 | 268篇 |
儿科学 | 645篇 |
妇产科学 | 1798篇 |
基础医学 | 2389篇 |
口腔科学 | 283篇 |
临床医学 | 16775篇 |
内科学 | 5700篇 |
皮肤病学 | 446篇 |
神经病学 | 2027篇 |
特种医学 | 843篇 |
外国民族医学 | 10篇 |
外科学 | 3322篇 |
综合类 | 78篇 |
一般理论 | 5篇 |
预防医学 | 2362篇 |
眼科学 | 217篇 |
药学 | 1007篇 |
中国医学 | 15篇 |
肿瘤学 | 1718篇 |
出版年
2024年 | 92篇 |
2023年 | 925篇 |
2022年 | 366篇 |
2021年 | 871篇 |
2020年 | 952篇 |
2019年 | 735篇 |
2018年 | 1705篇 |
2017年 | 1742篇 |
2016年 | 1872篇 |
2015年 | 2006篇 |
2014年 | 2224篇 |
2013年 | 2593篇 |
2012年 | 1720篇 |
2011年 | 1957篇 |
2010年 | 1730篇 |
2009年 | 1951篇 |
2008年 | 1605篇 |
2007年 | 1480篇 |
2006年 | 1355篇 |
2005年 | 1202篇 |
2004年 | 1052篇 |
2003年 | 905篇 |
2002年 | 778篇 |
2001年 | 582篇 |
2000年 | 387篇 |
1999年 | 514篇 |
1998年 | 669篇 |
1997年 | 747篇 |
1996年 | 693篇 |
1995年 | 622篇 |
1994年 | 454篇 |
1993年 | 369篇 |
1992年 | 318篇 |
1991年 | 308篇 |
1990年 | 296篇 |
1989年 | 238篇 |
1988年 | 181篇 |
1987年 | 172篇 |
1986年 | 161篇 |
1985年 | 164篇 |
1984年 | 131篇 |
1983年 | 130篇 |
1982年 | 116篇 |
1981年 | 104篇 |
1980年 | 67篇 |
1979年 | 94篇 |
1978年 | 76篇 |
1977年 | 77篇 |
1976年 | 75篇 |
1972年 | 95篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Jaafar Mouhyi Lars Sennerby Jeanjacques Pireaux Nicolas Dourov Samir Nammour Jack Van Reck 《Clinical oral implants research》1998,9(3):185-194
The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed. 相似文献
102.
J Emerg Nurs 1998;24:622. 相似文献
103.
Marek Motyka PhD Helena Motyka MA RN Romana Wsoek MA RN 《Journal of advanced nursing》1997,26(5):909-912
The paper presents the results of a pilot study which involved 50 nurses from several departments of internal medicine of The State Clinical Hospital of the Collegium Medicum, Jagiellonian University in Cracow. The results are based on the Statement Response Questionnaire. They show that the most common responses of the nurses in the face of anxiety expressed by patients are cheering up the patient, collecting information about the symptom, and offering explanation of the symptom. The least common responses included expressing one's own positive emotions and showing empathy towards the patient. 相似文献
104.
Most of the work of host defense has been carried out in mixed patient populations. It is now clear that elective preoperative surgical patients have totally different host defense capabilities as compared to posttrauma patients or those suffering from peritonitis. Specific cell-mediated immune studies need to be repeated in these 2 patient groups as well. What will contribute clinical relevance to these studies will be the means to correct the defects. If these defects or—more correctly termed—abnormalities of host defense are, indeed, important and contribute to an increased sepsis rate and mortality from sepsis in affected patients, then correcting them should reduce these complications. This hypothesis can only be tested when such means become available. The issues of most interest in the next few years will be the significance of serum albumin in host outcome, the role of immunomodulators, the involvement of cytokines in the overall process of host defense, and the use of specific nutritional support regimens targeted to the immune system.
Supported in part by grants from the Medical Research Council of Canada and the Fonds de recherche de Santé. 相似文献
Resumen La mayor parte del trabajo sobre los mecanismos de defensa del huésped ha sido realizada en poblaciones mixtas de pacientes. Actualmente aparece claro que los pacientes preoperatorios electivos poseen una capacidad de defensa de huésped totalmente diferente que la de los pacientes en estado posttrauma o de aquellos con peritonitis. Aparece necesario realizar estudios específicos de inmunidad celular en estos 2 grupos de pacientes; aquello que aporte pertinencia clínica en tales estudios habrá de representar medios para corregir estos defectos. Si tales defectos, mejor denominados anormalidades en las defensas del huésped, son de verdad importantes y contribuyen a mayores tasas de infección y de mortalidad por sepsis en los pacientes afectados, su corrección debe resultar en reducción de estas complicaciones. Esta hipótesis sólo puede ser puesta a prueba cuando tales medios se hallen disponibles. Los aspectos de mayor interés en los próximos años serán el significado de la albúmina sérica en la evolución final del huésped, el papel de los inmunomoduladores, la participación de las citocinas en el proceso general de defensa del huésped, y el uso de regimenes especificos de soporte nutricional dirigidos hacia el sistema inmune.
Résumé La plupart des travaux sur les mécanismes de défense ont été faits sur les populations mixtes. Il est à présent certain que les patients opérés électivement ont des mécanismes de défense préopératoire totalement différents de ceux des traumatisés ou des patients ayant une infection péritonéale. Les études immunologiques sur la médiation cellulaire spécifique méritent d'être refaites chez ces deux populations. Ce qui ressortira de ces études donnera les moyens de corriger les défauts ou plutôt les anomalies des mécanismes de défense qui contribuent à augmenter septicité et mortalité en rapport avec l'état septique. Cette hypothèse ne peut être vérifiée qu'avec ces moyens. Les questions les plus intéressantes dans les années à venir sera peut-être de connaître l'influence de l'albumine sérique sur l'évolution, le rôle des immunomodulaterus, celui des cytokinines dans le procédé global des mécanismes de défense, et celui de l'utilisation de l'alimentation spécifique pour améliorer le système immune.
Supported in part by grants from the Medical Research Council of Canada and the Fonds de recherche de Santé. 相似文献
105.
American Diabetes Association The initial draft of this paper was prepared by Rebecca G. Schafer MS RD ; Betsy Bohannon MS RD; Marion J. Franz MS RD; Janine Freeman RD; Alberta Holmes MS RD; Sue McLaughlin RD; Linda B. Haas RN; Davida F. Kruger MSN RN; Rodney A. Lorenz MD; Molly M.McMahon MD 《Journal of the American Dietetic Association》1997,97(1):52-53
106.
MARIE A. BERNARD MD VICKI LAMPLEY-DALLAS MD MPH LULA SMITH RN MPH 《Journal of the American Dietetic Association》1997,97(7):771-776
This article reviews the primary health problems of African-American, Hispanic-American, Asian/Pacific Islander-American, and Native-American elders. The goal is to familiarize practicing dietitians with the differences in longevity, disease spectrum, and functional status (where data are available) for each of these ethnic groups. These data should be of assistance in making decisions regarding dietary counseling for ethnic elders. It is acknowledged that most data accumulated according to race do not accurately measure ethnicity. The degree of acculturation may vary widely among individuals. Therefore, it is recommended that dietitians solicit clients’ perceptions of the factors that may contribute to illness and the barriers to implementing recommended remedies. 相似文献
107.
GLORIA L. KLEIN MS RD KIMBERLY KITA JUDITH FISH MMSc RD BARBARA SINKUS RN GORDON L. JENSEN MD PhD 《Journal of the American Dietetic Association》1997,97(8):885-888
Health care services and resources for older persons living in rural areas may be highly variable, and integrated service-delivery models are often lacking. This article presents a managed-care model of nutrition risk screening and intervention for older persons in rural areas. Nutrition risk screening was implemented by the Geisinger Health Care System, Danville, Pa, to target all eligible enrollees in a regional Medicare risk program. A single remote clinic site participating in the managed health care system was chosen for further study of a linked screening and case-management effort for undernourished persons. Screening and intervention at the clinic site selected for this study were guided by centralized expertise and resources. Individualized evaluation and intervention plans were developed with the aid of a dietitian and implemented by the clinic case manager. Of the 417 subjects who completed screening at the remote site, 68 met the risk criteria for undernutrition and were selected for case management. Many of the targeted persons received interventions that included evaluations by a physician or physician extender (eg, physician assistant, nurse practitioner) at the clinic and consultations with nutrition, mental health, or social services professionals. Twenty-six of the subjects who took part in the intervention completed a follow-up screening 6 months later. Ten of those persons no longer exhibited risk criteria. This demonstrates the feasibility of a linked screening and case management program for nutrition risk in the managed-care setting. J Am Diet Assoc. 1997; 97: 885-888. 相似文献
108.
109.
Susan Pelke RN David Easa MD 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1997,26(3):279-285
The clinical research coordinator plays a crucial role in organizing a site's participation in the expanding arena of multicenter medical and pharmacologic clinical trials. This summary clarifies the role of the clinical research coordinator for inexperienced staff members assuming these responsibilities and outlines planning procedures leading to successful implementation. Emphasis is placed on establishing an interdependent relationship with the principal investigator, careful protocol assessment, team building, and staff feedback. Useful tools such as study manuals and physicians' study orders are described. 相似文献
110.
Amanda Symington RN MHSc Marilyn Ballantyne RN MHSc Janet Pinelli RN MScN Bonnie Stevens RN PhD 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1995,24(4):321-326
Objective: To determine the effect of indwelling versus intermittent feeding tube placement on weight gain, apnea, and bradycardia in premature neonates.
Design: Eligible subjects were assigned randomly to either feeding tube method. Each subject was followed for 6 days.
Setting: The study was conducted in a secondary level neonatal intensive-care unit (NICU), a tertiary level NICU in a perinatal center, and a tertiary level NICU in a referral center.
Patients/Participants: Neonates who were 24–34 weeks gestational age, developmentally appropriate for gestational age, medically stable, on full enteral feedings through an orogastric or a nasogastric tube, and not fluid restricted. Ninety-three neonates were enrolled-49 in the indwelling group and 44 in the intermittent group. Nine neonates did not complete the study.
Interventions: Nasogastric indwelling feeding tubes were placed and left in site for up to 3 days. Orogastric intermittent feeding tubes were placed for each feeding and removed at completion of the feeding.
Main outcome measures: Weight gain, apnea, and bradycardia. Results: Members of both groups had similar demographic characteristics, clinical problems, and nutritional intake. No statistical differences were found between the two groups in weight gain or episodes of apnea and bradycardia.
Conclusions: There were no statistically or clinically significant differences between the two groups. The intermittent method of feeding is more expensive. Because no clinical differences were found, the type of tube placement chosen for feeding the premature infant may be based on economics. 相似文献
Design: Eligible subjects were assigned randomly to either feeding tube method. Each subject was followed for 6 days.
Setting: The study was conducted in a secondary level neonatal intensive-care unit (NICU), a tertiary level NICU in a perinatal center, and a tertiary level NICU in a referral center.
Patients/Participants: Neonates who were 24–34 weeks gestational age, developmentally appropriate for gestational age, medically stable, on full enteral feedings through an orogastric or a nasogastric tube, and not fluid restricted. Ninety-three neonates were enrolled-49 in the indwelling group and 44 in the intermittent group. Nine neonates did not complete the study.
Interventions: Nasogastric indwelling feeding tubes were placed and left in site for up to 3 days. Orogastric intermittent feeding tubes were placed for each feeding and removed at completion of the feeding.
Main outcome measures: Weight gain, apnea, and bradycardia. Results: Members of both groups had similar demographic characteristics, clinical problems, and nutritional intake. No statistical differences were found between the two groups in weight gain or episodes of apnea and bradycardia.
Conclusions: There were no statistically or clinically significant differences between the two groups. The intermittent method of feeding is more expensive. Because no clinical differences were found, the type of tube placement chosen for feeding the premature infant may be based on economics. 相似文献