全文获取类型
收费全文 | 76454篇 |
免费 | 9734篇 |
国内免费 | 218篇 |
专业分类
耳鼻咽喉 | 581篇 |
儿科学 | 1993篇 |
妇产科学 | 2717篇 |
基础医学 | 7799篇 |
口腔科学 | 1094篇 |
临床医学 | 21548篇 |
内科学 | 13195篇 |
皮肤病学 | 874篇 |
神经病学 | 5612篇 |
特种医学 | 2411篇 |
外科学 | 10520篇 |
综合类 | 835篇 |
一般理论 | 57篇 |
预防医学 | 7453篇 |
眼科学 | 1337篇 |
药学 | 4230篇 |
1篇 | |
中国医学 | 54篇 |
肿瘤学 | 4095篇 |
出版年
2023年 | 1092篇 |
2022年 | 555篇 |
2021年 | 1415篇 |
2020年 | 1283篇 |
2019年 | 1336篇 |
2018年 | 2419篇 |
2017年 | 2309篇 |
2016年 | 2447篇 |
2015年 | 2730篇 |
2014年 | 3349篇 |
2013年 | 4290篇 |
2012年 | 4333篇 |
2011年 | 4723篇 |
2010年 | 3218篇 |
2009年 | 3243篇 |
2008年 | 4140篇 |
2007年 | 4309篇 |
2006年 | 4219篇 |
2005年 | 4006篇 |
2004年 | 3683篇 |
2003年 | 3488篇 |
2002年 | 3267篇 |
2001年 | 1352篇 |
2000年 | 1117篇 |
1999年 | 1254篇 |
1998年 | 1231篇 |
1997年 | 1218篇 |
1996年 | 1127篇 |
1995年 | 1079篇 |
1994年 | 842篇 |
1993年 | 734篇 |
1992年 | 793篇 |
1991年 | 725篇 |
1990年 | 738篇 |
1989年 | 648篇 |
1988年 | 569篇 |
1987年 | 507篇 |
1986年 | 506篇 |
1985年 | 568篇 |
1984年 | 472篇 |
1983年 | 399篇 |
1982年 | 335篇 |
1981年 | 320篇 |
1980年 | 262篇 |
1979年 | 318篇 |
1978年 | 291篇 |
1977年 | 249篇 |
1976年 | 248篇 |
1974年 | 241篇 |
1972年 | 269篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
This paper describes a complex set of patient and nursing data from 83 psychiatric wards. It explains how the data were collected and organized into a meaningful format using a quality league-table. The patient and nursing characteristics of high quality psychiatric wards ranking above the 74th percentile and the characteristics of low quality wards falling below the 26th percentile are compared and examined in detail. Startling similarities and differences in patient activity, nursing activity, and nursing quality in high and low quality wards are highlighted. Finally, some implications of the findings for nursing practice, management, and education are considered. 相似文献
52.
Vivian E. von Gruenigen M.D. Joseph T. Santoso M.D. Robert L. Coleman M.D. Carolyn Y. Muller M.D. David Scott Miller M.D. J.Michael Mathis Ph.D. 《Gynecologic oncology》1998,69(3):197-204
Objectives.To test the safety, efficacy, and toxicity of gene therapy using wild-type p53-expressing adenovirus (Ad-CMV-p53) in a nude mouse model with intraperitoneal (ip) 2774 human ovarian cancer cell line that contains a p53 mutation.Study design.An initial study of adenovirus tolerance was determined in nude mice by a single ip injection of increasing doses of Ad-CMV-p53. Nude mice were implanted with an LD100dose of 1 × 107cells. To study the efficacy and specificity of Ad-CMV-p53 treatment, the mice received treatment with different adenovirus constructs. One group received Ad-CMV-p53 and another group received a control adenovirus construct, Ad-CMV-βgal. To study the treatment response to Ad-CMV-p53, the mice were divided into groups and received various treatment schedules of 1 × 108pfu of Ad-CMV-p53.Results.The mice tolerated Ad-CMV-p53 without adverse effects at doses of 1 × 108pfu. The response to Ad-CMV-p53 showed significant survival duration in each dose regimen, with a survival time greater than that of untreated animals (P= 0.0173). However, no statistically significant survival advantage was observed between Ad-CMV-p53- and Ad-CMV-βgal-treated mice.Conclusions.These studies show that at the adenovirus dose and administration regimen used, there is effective but not specific 2774 tumor growth inhibitionin vivo.Efficient introduction of biologically active genes into tumor cells would greatly facilitate cancer therapy. Thus, although promising, these results caution that much effort will be required to realize the potential for clinical application of adenovirus-based ovarian cancer gene therapy. 相似文献
53.
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
54.
J. Wayne Streilein Scott Cousins Jo S. P. Williamson 《International ophthalmology》1990,14(5-6):317-325
Regulation of T cell-dependent immune responses is mediated in part by bone marrow-derived antigen presenting cells (APC) that (a) process and present antigens which engage the T cell receptor and (b) secrete cytokines that influence the threshold of T cell activation. The anterior chamber of the eye is lined by the corneal endothelium (which rests on a stroma and epithelium that is devoid of class II MHC + APC) and iris/ciliary body (which contain significant numbers of bone marrow-derived cells, one third of which are class II MHC +). When tested in vitro, these potential APCs fail to present antigens in a form that activates T cells. Moreover, iris/ciliary body cells actually suppress activation of T cells exposed to antigens on conventional APC. In addition, aqueous humor under normal circumstances contains factors (one of which is TGFB) that are potent inhibitors of antigen-driven T cell activation, but spare other aspects of T cell function. Evidence suggests that the bone marrow-derived cells in iris/ciliary body are the source of this factor. Thus, the anterior chamber contains powerful forces that can prevent induction and can suppress expression of T cell mediated immunity. It is proposed that these forces are responsible for immunologic privilege and anterior chamber associated immune deviation, and for suppressing pathologic proliferation and inflammation in the anterior segment of the eye. 相似文献
55.
56.
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
57.
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
58.
Maritta Välimäki Lic. NSc RN & Helena Leino-Kilpi PhD RN 《Journal of advanced nursing》1998,27(1):204-212
In the context of an interview study concerned with self-determination in psychiatric patients, this paper describes the preconditions for and consequences of self-determination from the point of view of psychiatric patients themselves. The data were collected in semi-structured interviews with long-term psychiatric patients ( n =72) and analysed using the method of content analysis. Responses on the preconditions for self-determination were grouped into three categories: firstly, there were those who said that reference to self-determination in the case of psychiatric patients is nonsense; secondly, there were those who said that self-determination requires no preconditions; and thirdly, there were those who said that there are certain preconditions, such as the ability to think and make decisions, activity, obedience, and illness. Both positive and negative consequences were identified in situations where self-determination is maintained, but only negative consequences in situations where self-determination is lost. On the basis of these tentative results, self-determination seemed to be relevant in psychiatric nursing. We are continuing to develop and test an instrument for the evaluation of the opportunity for self-determination in clinical practice. 相似文献
59.
J. Pepke-Zaba T. W. Higenbottam A. T. Dinh Xuan J. P. Scott T. A. H. English J. Wallwork 《Transplant international》1990,3(1):108-112
Abstract. Twenty-one patients were studied at rest and during exercise after heart transplantation to compare cardiac output measured by thermodilution and impedance cardiography. Exercise was performed on a bicycle ergometer over a limited range of work load (25 and 50 watt) whilst metabolic gas exchange was recorded. One patient was studied at rest whilst his circulation was maintained by a Jarvik-7 artificial heart. The values of cardiac output measured by impedance cardiography corresponded closely with the flow rate from the artificial heart. There was also close agreement between the impedance and thermodilution measurements of cardiac output at rest and during exercise. Both measurements followed the changes in heart rate and oxygen consumption. Both thermodilution and impedance cardiography methods elicited good reproducibility of cardiac output measurements at rest and during exercise. These observations suggest that the noninvasive and continuous record of cardiac output obtained by impedance cardiography can be used for the postoperative monitoring of heart transplant recipients. 相似文献
60.