全文获取类型
收费全文 | 4095篇 |
免费 | 352篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 75篇 |
儿科学 | 106篇 |
妇产科学 | 148篇 |
基础医学 | 609篇 |
口腔科学 | 57篇 |
临床医学 | 393篇 |
内科学 | 1033篇 |
皮肤病学 | 41篇 |
神经病学 | 451篇 |
特种医学 | 137篇 |
外科学 | 511篇 |
综合类 | 46篇 |
一般理论 | 2篇 |
预防医学 | 250篇 |
眼科学 | 122篇 |
药学 | 272篇 |
中国医学 | 2篇 |
肿瘤学 | 217篇 |
出版年
2021年 | 28篇 |
2019年 | 56篇 |
2018年 | 53篇 |
2017年 | 41篇 |
2016年 | 49篇 |
2015年 | 57篇 |
2014年 | 60篇 |
2013年 | 123篇 |
2012年 | 135篇 |
2011年 | 131篇 |
2010年 | 84篇 |
2009年 | 80篇 |
2008年 | 113篇 |
2007年 | 166篇 |
2006年 | 151篇 |
2005年 | 151篇 |
2004年 | 157篇 |
2003年 | 132篇 |
2002年 | 130篇 |
2001年 | 140篇 |
2000年 | 139篇 |
1999年 | 124篇 |
1998年 | 68篇 |
1997年 | 54篇 |
1996年 | 55篇 |
1995年 | 46篇 |
1994年 | 44篇 |
1993年 | 37篇 |
1992年 | 116篇 |
1991年 | 118篇 |
1990年 | 118篇 |
1989年 | 112篇 |
1988年 | 110篇 |
1987年 | 88篇 |
1986年 | 100篇 |
1985年 | 106篇 |
1984年 | 86篇 |
1983年 | 79篇 |
1982年 | 54篇 |
1981年 | 50篇 |
1980年 | 47篇 |
1979年 | 89篇 |
1978年 | 65篇 |
1977年 | 54篇 |
1976年 | 50篇 |
1975年 | 40篇 |
1974年 | 64篇 |
1973年 | 51篇 |
1972年 | 33篇 |
1967年 | 40篇 |
排序方式: 共有4472条查询结果,搜索用时 15 毫秒
71.
72.
OBJECTIVE: The aim of the study was to assess the contraction of myocardium stunned by repetitive brief coronary occlusions by examining the response to alterations in loading and inotropy of systolic contraction on isovolumetric and ejection phase shortening. METHODS: Fourteen open chest anaesthetised dogs were used for the studies. After destruction of the sinus node, the heart was atrially paced and atrial extrasystoles were introduced followed by a short (400 ms) or long (700 ms) postextrasystole. The left anterior descending coronary artery was occluded for 5 min and reperfused for 10 min a total of eight times to produce stunned myocardium, followed by a final 60 min of reflow. Regional function was assessed with segment length sonomicrometers. RESULTS: With successive periods of occlusion there was an increase in the end diastolic segment length and a progressive decrease in total percent systolic shortening (baseline 22.3%, 1st reflow 14.5%, 8th reflow 7.9%) with some recovery after 60 min of reflow (12.0%). This was predominantly due to the development of bulging during isovolumetric systole (4.5%, -4.9%, and -8.3%, respectively) which diminished during 60 min recovery to -3.1%. Ejection shortening was relatively constant (17.8%, 19.4%, 16.3%, and 15.1%, respectively). Postextrasystolic potentiation resulted in an increased in total percent systolic shortening, but not to the baseline value, as slight isovolumetric bulging persisted. Similar changes were seen with the short and long postextrasystoles although the latter had a greater increase in ejection shortening. CONCLUSIONS: The decrease in function after repetitive occlusion and reflow is predominantly due to bulging during isovolumetric systole which persists after postextrasystolic potentiation in our model of stunned myocardium. 相似文献
73.
Gabriela Vazquez-Benitez Jay R. Desai Stanley Xu Glenn K. Goodrich Emily B. Schroeder Gregory A. Nichols Jodi Segal Melissa G. Butler Andrew J. Karter John F. Steiner Katherine M. Newton Leo S. Morales Ram D. Pathak Abraham Thomas Kristi Reynolds H. Lester Kirchner Beth Waitzfelder Jennifer Elston Lafata Renuka Adibhatla Zhiyuan Xu Patrick J. O’Connor 《Diabetes care》2015,38(5):905-912
OBJECTIVEThe objective of this study was to assess the incidence of major cardiovascular (CV) hospitalization events and all-cause deaths among adults with diabetes with or without CV disease (CVD) associated with inadequately controlled glycated hemoglobin (A1C), high LDL cholesterol (LDL-C), high blood pressure (BP), and current smoking.RESULTSMean (SD) age at baseline was 59 (14) years; 48% of subjects were female, 45% were white, and 31% had CVD. Mean follow-up was 59 months. Event rates per 100 person-years for adults with diabetes and CVD versus those without CVD were 6.0 vs. 1.7 for MI/ACS, 5.3 vs. 1.5 for stroke, 8.4 vs. 1.2 for HF, 18.1 vs. 40 for all CV events, and 23.5 vs. 5.0 for all-cause mortality. The percentages of CV events and deaths associated with inadequate risk factor control were 11% and 3%, respectively, for those with CVD and 34% and 7%, respectively, for those without CVD.CONCLUSIONSAdditional attention to traditional CV risk factors could yield further substantive reductions in CV events and mortality in adults with diabetes. 相似文献
74.
75.
76.
77.
Terrell DR Beebe LA Neas BR Vesely SK Segal JB George JN 《American journal of hematology》2012,87(9):848-852
To determine the prevalence of immune thrombocytopenia (ITP) in Oklahoma regardless of age, clinical characteristics, insurance status, and source of health care. Patients with ITP were identified by the administrative code ICD‐9‐CM 287.3 in Oklahoma hematologists' offices for a 2‐year period, 2003–2004. Prevalence was estimated separately for children (<16 years old) and adults because of their distinct clinical characteristics. Oklahoma census data for 2000 was used as the denominator. Eighty‐seven (94%) of 93 eligible Oklahoma hematologists participated; 620 patients with ITP were identified. The average annual prevalences were as follows: 8.1 (95% CI: 6.7–9.5) per 100,000 children, 12.1 (95% CI: 11.1–13.0) per 100,000 adults, and 11.2 (95% CI: 10.4–12.0) per 100,000 population. Among children and adults less than age 70 years, the prevalence was greater among women. Among adults aged 70 years and older, the prevalence was greater among men. The highest prevalence of ITP was among men age 80 years and older. These data document for the first time the prevalence of ITP regardless of age, clinical characteristics, insurance status, and source of health care. The methodology developed for this prevalence analysis may be adaptable for epidemiologic studies of other uncommon disorders which lack specific diagnostic criteria and are treated primarily by medical specialists. Am. J. Hematol. 2012. © 2012 Wiley Periodicals, Inc. 相似文献
78.
79.
80.
Segal JB 《Journal of general internal medicine》2012,27(Z1):S20-S27
In this chapter of the Evidence-based Practice Centers Methods Guide for Medical Tests, we describe how the decision to use a medical test generates a broad range of outcomes and that each of these outcomes should be considered for inclusion in a systematic review. Awareness of these varied outcomes affects how a decision maker balances the benefits and risks of the test; therefore, a systematic review should present the evidence on these diverse outcomes. The key outcome categories include clinical management outcomes and direct health effects; emotional, social, cognitive, and behavioral responses to testing; legal and ethical outcomes, and costs. We describe the challenges of incorporating these outcomes in a systematic review, suggest a framework for generating potential outcomes for inclusion, and describe the role of stakeholders in choosing the outcomes for study. Finally, we give examples of systematic reviews that either included a range of outcomes or that might have done so. The following are the key messages in this chapter: Consider both the outcomes that are relevant to the process of testing and those that are relevant to the results of the test. Consider inclusion of outcomes in all five domains: clinical management effects, direct test effects; emotional, social, cognitive and behavioral effects; legal and ethical effects, and costs. Consider to which group the outcomes of testing are most relevant. Given resource limitations, prioritize which outcomes to include. This decision depends on the needs of the stakeholder(s), who should be assisted in prioritizing the outcomes for inclusion. 相似文献