全文获取类型
收费全文 | 1296篇 |
免费 | 55篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 31篇 |
妇产科学 | 35篇 |
基础医学 | 120篇 |
口腔科学 | 28篇 |
临床医学 | 139篇 |
内科学 | 237篇 |
皮肤病学 | 9篇 |
神经病学 | 162篇 |
特种医学 | 202篇 |
外科学 | 96篇 |
综合类 | 20篇 |
一般理论 | 4篇 |
预防医学 | 80篇 |
眼科学 | 13篇 |
药学 | 89篇 |
肿瘤学 | 122篇 |
出版年
2021年 | 13篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 30篇 |
2013年 | 40篇 |
2012年 | 29篇 |
2011年 | 42篇 |
2010年 | 38篇 |
2009年 | 41篇 |
2008年 | 36篇 |
2007年 | 52篇 |
2006年 | 40篇 |
2005年 | 35篇 |
2004年 | 36篇 |
2003年 | 36篇 |
2002年 | 45篇 |
2001年 | 29篇 |
2000年 | 22篇 |
1999年 | 23篇 |
1998年 | 55篇 |
1997年 | 47篇 |
1996年 | 44篇 |
1995年 | 33篇 |
1994年 | 26篇 |
1993年 | 36篇 |
1992年 | 19篇 |
1991年 | 27篇 |
1990年 | 27篇 |
1989年 | 41篇 |
1988年 | 31篇 |
1987年 | 35篇 |
1986年 | 32篇 |
1985年 | 33篇 |
1984年 | 25篇 |
1983年 | 26篇 |
1982年 | 18篇 |
1981年 | 21篇 |
1980年 | 22篇 |
1979年 | 9篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1975年 | 10篇 |
1974年 | 12篇 |
1973年 | 10篇 |
1972年 | 10篇 |
1971年 | 9篇 |
排序方式: 共有1391条查询结果,搜索用时 15 毫秒
71.
The fate of the open canalicular system in surface and suspension- activated platelets 总被引:6,自引:0,他引:6
We have examined the movement of fibrinogen-gold (fgn-Au) complexes in platelets activated in suspension and by surface contact. Fgn-Au probes did not react with resting cells but were bound to the external membrane of platelets in suspension 5 seconds after addition of 1 U/mL of thrombin. At intervals over a period of 5 to 20 minutes, fgn-Au probes moved from the cell surface to peripheral and then deep channels of the open canalicular system (OCS). When platelets were surface activated by exposure to carbon-stabilized, formvar-coated grids for 5 to 20 minutes and then exposed to fgn-Au complexes for 5 minutes, probes were also observed in the OCS. At 5 minutes, over 40% of the platelets had concentrated fgn-Au in their OCS. Results after 10 minutes revealed 25% with gold-filled channels, 16% after 15 minutes, and 5% after 20 minutes. The decrease in frequency of OCS staining correlated with the increasing frequency of spread platelets, suggesting that tension produced by spreading may cause collapse of the OCS or that the OCS may evaginate onto the platelet during spreading. To evaluate the latter hypothesis, platelets were initially exposed to grids for 5 minutes and then incubated with fgn-Au for intervals of 5 to 20 minutes. The frequency of platelets with fgn-Au concentrated in the OCS was greatest at 5 minutes (44%) and decreased at the same rate as the frequency of spread platelets increased. Only 14.7% of the cells contained fgn-Au in the OCS after 20 minutes. These were primarily dendritic in form, while fully spread platelets rarely contained an OCS filled with the probe. The study indicates that fgn-Au particles are cleared to channels of the OCS independent of the mechanism of platelet activation. Fgn-Au that has been concentrated in the OCS at early stages of surface activation can be externalized during platelet spreading but remain internalized in suspension-activated cells. The OCS represents a membrane reservoir that can be evaginated onto the platelet surface during interaction with surfaces. 相似文献
72.
Erik G. Gunderson Matthew P. Lillyblad Michelle Fine Orly Vardeny Theodore J. Berei 《Pharmacotherapy》2019,39(4):473-485
Volume management in acute decompensated and chronic heart failure (HF) remains a significant challenge. Although progress has been made in the development of mortality-reducing neurohormonal regimens in the reduced ejection fraction population, no clinical trial has yet demonstrated anything more than symptomatic relief or biomarker reduction with pharmacotherapeutic volume-based interventions made in the acutely decompensated individual or those with evolving outpatient congestion. As the number of patients with HF continues to grow, in addition to HF-related hospitalizations, identifying therapies that have the potential to aid in diuresis more safely and efficaciously is paramount to decreasing inpatient length of stay and preventing unnecessary admissions. More recently, a significant amount of research has been dedicated to the use of vasopressin antagonists, specifically tolvaptan, as adjunctive therapy to loop and thiazide diuretics. Although these agents do not seem to have a pervasive role in fluid management in the acute decompensated and chronic HF populations, they are effective tools to have available for specific clinical situations. This review summarizes the literature surrounding the use of tolvaptan for volume management in congestive HF, as well as offering practical guidance for use of this agent. 相似文献
73.
Catharina Carolina de Jong Wynand JG Ros Guus Schrijvers 《Journal of medical Internet research》2014,16(1)
Background
In support of professional practice, asynchronous communication between the patient and the provider is implemented separately or in combination with Internet-based self-management interventions. This interaction occurs primarily through electronic messaging or discussion boards. There is little evidence as to whether it is a useful tool for chronically ill patients to support their self-management and increase the effectiveness of interventions.Objective
The aim of our study was to review the use and usability of patient-provider asynchronous communication for chronically ill patients and the effects of such communication on health behavior, health outcomes, and patient satisfaction.Methods
A literature search was performed using PubMed and Embase. The quality of the articles was appraised according to the National Institute for Health and Clinical Excellence (NICE) criteria. The use and usability of the asynchronous communication was analyzed by examining the frequency of use and the number of users of the interventions with asynchronous communication, as well as of separate electronic messaging. The effectiveness of asynchronous communication was analyzed by examining effects on health behavior, health outcomes, and patient satisfaction.Results
Patients’ knowledge concerning their chronic condition increased and they seemed to appreciate being able to communicate asynchronously with their providers. They not only had specific questions but also wanted to communicate about feeling ill. A decrease in visits to the physician was shown in two studies (P=.07, P=.07). Increases in self-management/self-efficacy for patients with back pain, dyspnea, and heart failure were found. Positive health outcomes were shown in 12 studies, where the clinical outcomes for diabetic patients (HbA1c level) and for asthmatic patients (forced expiratory volume [FEV]) improved. Physical symptoms improved in five studies. Five studies generated a variety of positive psychosocial outcomes.Conclusions
The effect of asynchronous communication is not shown unequivocally in these studies. Patients seem to be interested in using email. Patients are willing to participate and are taking the initiative to discuss health issues with their providers. Additional testing of the effects of asynchronous communication on self-management in chronically ill patients is needed. 相似文献74.
75.
Tyler J. Albert Joel Bradley Helene Starks Jeff Redinger Cherinne Arundel Albertine Beard Laura Caputo Jonathan Chun Craig G. Gunderson Dan Heppe Anand Jagannath Kyle Kent Michael Krug James Laudate Vignesh Palaniappan Amanda Pensiero Zaven Sargsyan Emily Sladek Matthew Tuck Paul B. Cornia 《Journal of general internal medicine》2022,37(6):1422
ImportanceThe COVID-19 pandemic disrupted graduate medical education, compelling training programs to abruptly transition to virtual educational formats despite minimal experience or proficiency. We surveyed residents from a national sample of internal medicine (IM) residency programs to describe their experiences with the transition to virtual morning report (MR), a highly valued core educational conference.ObjectiveAssess resident views about virtual MR content and teaching strategies during the COVID-19 pandemic.DesignAnonymous, web-based survey.ParticipantsResidents from 14 academically affiliated IM residency programs.Main MeasuresThe 25-item survey on virtual MR included questions on demographics; frequency and reason for attending; opinions on who should attend and teach; how the virtual format affects the learning environment; how virtual MR compares to in-person MR with regard to participation, engagement, and overall education; and whether virtual MR should continue after in-person conferences can safely resume. The survey included a combination of Likert-style, multiple option, and open-ended questions.ResultsSix hundred fifteen residents (35%) completed the survey, with a balanced sample of interns (39%), second-year (31%), and third-year (30%) residents. When comparing their overall assessment of in-person and virtual MR formats, 42% of residents preferred in-person, 18% preferred virtual, and 40% felt they were equivalent. Most respondents endorsed better peer-engagement, camaraderie, and group participation with in-person MR. Chat boxes, video participation, audience response systems, and smart boards/tablets enhanced respondents’ educational experience during virtual MR. Most respondents (72%) felt that the option of virtual MR should continue when it is safe to resume in-person conferences.ConclusionsVirtual MR was a valued alternative to traditional in-person MR during the COVID-19 pandemic. Residents feel that the virtual platform offers unique educational benefits independent of and in conjunction with in-person conferences. Residents support the integration of a virtual platform into the delivery of MR in the future.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11606-021-06963-7.KEY WORDS: graduate medical education, internal medicine residency, morning report, virtual 相似文献
76.
77.
78.
Objective To explore the characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods Seven patients with arrhythmogenic right ventricular cardiomyopathy and 34 members of three families were studied. All patients and family members underwent history collection, clinical examination, electrocardiogram (ECG), two-dimensional echocardiography (2-DE) and a signal averaging electrocardiogram. Programmed ventricular stimulation was performed in five patients. Results All patients and family members had normal morphologic characteristics and normal function of the left ventricular by 2-DE. Fourteen persons had abnormal findings indicating ARVC. Five had enlargement of the right ventricular with diffused hypocontractility, eight had thin and systolic bulging in the focal anterior wall with hypokinesia and one had bulging of the inferior wall. Twenty-five persons (seven patients and 18 family members) had abnormal findings in ECG. Positive ventricular late potential was recorded in 13 persons (six patients). Two to three monomorphic ventricular tachycardia (VT) with left bundle branch block (LBBB) configurations were induced in five patients. Ventricular fibrillation was induced in two patients during the electrophysiologic study (EPS). Five patients had very high pacing threshold and/or ineffective pacing in one or many regions of the right ventricle. Two members of one family died suddenly. One member was a dwarf with ARVC. Spontaneous VT with a left bundle branch block (LBBB) configuration was recorded in five patients, polymorphic VT with extremely short coupling interval in one, and premature ventricular complexes with LBBB configuration in 12 (six patients). Conclusion Our familial study strongly suggests that ARVC may be a hereditary disease and it is helpful in the diagnosis and detection of ARVC. The most common manifestations were abnormal structure and function of the right ventricle and abnormal ECG of repolarization and ventricular arrhythmia which originates from the right ventricle. 相似文献
79.
P E Gunderson 《American journal of surgery》1987,154(5):538-540
The half-hitch knot, an alternative to the square knot for tying a suture, has been presented. A square knot is satisfactory, but because of its configuration it is difficult to tie, and in actual practice it is seldom used. Instead, a series of half hitches is tied. A half-hitch knot is as secure as a square knot and much easier to tie. However, it too must be tied in proper configuration to be reliable. The technique for tying a half-hitch knot and some of its characteristics are described. 相似文献
80.