全文获取类型
收费全文 | 17239篇 |
免费 | 955篇 |
国内免费 | 68篇 |
专业分类
耳鼻咽喉 | 215篇 |
儿科学 | 520篇 |
妇产科学 | 381篇 |
基础医学 | 2525篇 |
口腔科学 | 910篇 |
临床医学 | 1994篇 |
内科学 | 3310篇 |
皮肤病学 | 362篇 |
神经病学 | 1554篇 |
特种医学 | 308篇 |
外科学 | 1395篇 |
综合类 | 127篇 |
一般理论 | 10篇 |
预防医学 | 2061篇 |
眼科学 | 300篇 |
药学 | 1132篇 |
中国医学 | 84篇 |
肿瘤学 | 1074篇 |
出版年
2024年 | 19篇 |
2023年 | 181篇 |
2022年 | 355篇 |
2021年 | 684篇 |
2020年 | 408篇 |
2019年 | 612篇 |
2018年 | 653篇 |
2017年 | 468篇 |
2016年 | 466篇 |
2015年 | 570篇 |
2014年 | 741篇 |
2013年 | 923篇 |
2012年 | 1456篇 |
2011年 | 1577篇 |
2010年 | 768篇 |
2009年 | 678篇 |
2008年 | 1164篇 |
2007年 | 1104篇 |
2006年 | 1036篇 |
2005年 | 930篇 |
2004年 | 789篇 |
2003年 | 753篇 |
2002年 | 724篇 |
2001年 | 102篇 |
2000年 | 78篇 |
1999年 | 73篇 |
1998年 | 138篇 |
1997年 | 87篇 |
1996年 | 74篇 |
1995年 | 61篇 |
1994年 | 59篇 |
1993年 | 54篇 |
1992年 | 35篇 |
1991年 | 39篇 |
1990年 | 36篇 |
1989年 | 16篇 |
1988年 | 19篇 |
1987年 | 25篇 |
1986年 | 28篇 |
1985年 | 22篇 |
1984年 | 27篇 |
1983年 | 28篇 |
1982年 | 29篇 |
1981年 | 25篇 |
1980年 | 25篇 |
1979年 | 17篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 10篇 |
1930年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Azra M. Sehic Lillian W. Gaber Shane Roy III Paula M. Miller Stephen B. Kritchevsky Robert J. Wyatt 《Pediatric nephrology (Berlin, Germany)》1997,11(4):435-437
Based upon the percentage of cases of IgA nephropathy (IgAN) in biopsy series, a lower prevalence has been assumed for African-Americans
compared with Americans of European descent. This may be due to a racial difference in the basic underlying pathology of IgAN
or to racial differences in patterns of referral and biopsy selection practices. Over the past decade (1985 – 1994), we have
found similar incidences of IgAN in Caucasian and African-American children from Shelby County, Tennessee. The incidence was
3.0 cases per million per year for Caucasian and 5.7 cases per million per year for African-American children. IgAN may be
more common in African-American children than previously appreciated. Population-based incidence studies will be necessary
to determine whether or not our experience has become a more widespread phenomenon.
Received August 21, 1996; received in revised form and accepted December 18, 1996 相似文献
32.
Nuno Fonseca Filomena Caetano José Santos Filipe Seixo Leonel Bernardino Isabel Silvestre Paula Cardoso Filomena Segurado Lopes Inês 《Revista portuguesa de cardiologia》2004,23(3):365-375
INTRODUCTION: In patients (pts) with atrial fibrillation (AF) of more than 48 hours' duration, electrical cardioversion (ECV) should only be performed after 3 weeks of effective anticoagulation. Transesophageal echocardiography (TEE) allows earlier ECV; however, despite exclusion of thrombi in the atrium and left atrial appendage (LAA), cases of thromboembolism related to ECV have been documented in AF. To define a low-risk group for cardioversion without previous anticoagulation, pts were selected for immediate ECV if no thrombi or dynamic spontaneous echo contrast (auto-contrast) were found after TEE and if LAA velocity was more than 0.25 m/sec. METHODS AND RESULTS: We performed TEE in 31 consecutive pts referred for ECV for AF of more than 48 hours' duration and without previous anticoagulation. After TEE the pts eligible for immediate ECV began anticoagulation with low molecular weight heparin (enoxaparin), subcutaneously in therapeutic doses, together with warfarin immediately before cardioversion. Enoxaparin was continued until an INR of over 2 was reached. Based on the TEE findings, the pts were divided in 2 groups: immediate ECV, group A, 20 pts with a mean age of 62 +/- 13 years, 6 female; and conventional therapy with warfarin before ECV, group B, 11 pts, mean age of 67 +/- 10 years (p < 0.05), 2 female. None of the pts in either group had mitral stenosis or previous episodes of thromboembolism. The mean transverse diameter of the left atrium in the 31 pts was 47 +/- 4.5 mm, without statistically significant differences between the 2 groups. Of the 11 pts in group B, 3 had a thrombus in the LAA, 6 dynamic spontaneous echo contrast and the remainder LAA velocities of less than 0.25 m/sec. ECV was achieved in all the pts, with no complications. Oral anticoagulation was maintained for at least a month. At one month, sinus rhythm was maintained in 75% of group A and 45% of group B (p < 0.01). CONCLUSION: In pts with AF of more than 48 hours' duration and no previous history of thromboembolism, the use of our exclusion criteria during TEE enabled stratification of a low-risk population for immediate ECV, which was accomplished effectively and safely in 2/3 of the pts. This strategy is associated with early symptomatic improvement, and may contribute to maintenance of sinus rhythm after one month, which was significantly better than in the pts who had prolonged therapy with warfarin before ECV, despite the differences found in age and left ventricular function. 相似文献
33.
Neuropsychiatric symptoms are common in older adults with dementia and can be associated with a rapid decline in cognitive and functional status. This article reviews the current literature supporting the use of atypical antipsychotic medications in this population. Among the currently available atypical antipsychotics, risperidone and olanzapine have been the most widely studied in double-blind, randomized, placebo-controlled clinical trials. Despite the common use of other atypical antipsychotic medications, their efficacy and safety in older adults with dementia has not been as extensively studied. Some controversy surrounds the use of atypical antipsychotic agents in older adults with the suggestion that they may increase the incidence of stroke or even death. Despite the potential for increased risk of harm from the use of these medications, atypical antipsychotics are often effective in treating troublesome neuropsychiatric symptoms refractory to other treatments. Whenever possible, these atypical antipsychotic drug treatments should be combined with non-pharmacological treatments to limit the need and dose of antipsychotic drugs and constant monitoring for potential harms should be maintained. The choice of which atypical antipsychotic agent can be guided by the nature and severity of the target symptom and the medication least likely to cause harm to the patient. 相似文献
34.
35.
Psychiatric Quarterly - 相似文献
36.
We report a malformed infant with a de novo interstitial deletion of 4q. This is the second patient reported with del(4) (q25q27). Although there are several common features such as marked hypotonia, cardiac abnormalities, cleft palate, and micrognathia noted in our case and that of Chudley et al. (1988), we conclude from our comparison of the seven previously reported cases involving deletions of bands 4(q25q27) that a specific phenotype cannot yet be described for this deletion. 相似文献
37.
BACKGROUND: When and whether early enteral nutrition (EN) benefits critically ill patients is debatable. This prospective clinical audit aimed to evaluate the feasibility of an early EN protocol and to identify factors that may hinder EN delivery in critically ill patients. METHODS: Thirty-six medical patients with severe respiratory failure under invasive ventilation and scheduled to receive early EN, with a length of ICU stay >72 hours, were included. As asserted by the Society of Critical Care Medicine, 8% of patients were priority 1, 72% priority 2, and 20% priority 3 for intensive therapeutic and vital support interventions. RESULTS: Overall, because of gastrointestinal complications, only 39% of the prescribed EN was administered; only 8 (22%) patients did tolerate EN within the first 48 hours after admission and did achieve their minimum nutritional requirements. The most frequent complication (78%) was high volume of gastric residuals followed by abdominal distention (61%), both associated with hemodynamic instability (HI). Gastrointestinal dysfunction was associated with high Acute Physiologic and Chronic Health Evaluation II score (p = .01), total calorie intake (p = .02), total carbohydrate intake (p = .02), HI (p = .03), malnutrition (p = .04), volume of IV saline (p = .04), and concurrent vasoactive drug administration (p = .05). CONCLUSIONS: This audit in extremely severe intensive care patients identified several factors that impair gastrointestinal function and preclude EN at any stage, namely early EN. Nutrition management must take into account concurrent therapies, given their potential interference with nutrition and organ function. 相似文献
38.
39.
40.
A tailored proficiency test programme in high-resolution gamma-spectrometric analysis has been established for the radionuclide laboratories designated to support the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). It entails certified reference samples that contain fission products relevant to the CTBT. The sample geometries and materials correspond to aerosol filter samples from the high-volume samplers of the radionuclide stations of the International Monitoring System (IMS) and the related calibration sources are matrix and geometry matched to the reference samples. 相似文献