全文获取类型
收费全文 | 107543篇 |
免费 | 6555篇 |
国内免费 | 475篇 |
专业分类
耳鼻咽喉 | 1191篇 |
儿科学 | 2718篇 |
妇产科学 | 1932篇 |
基础医学 | 13329篇 |
口腔科学 | 1886篇 |
临床医学 | 11159篇 |
内科学 | 22062篇 |
皮肤病学 | 1486篇 |
神经病学 | 10839篇 |
特种医学 | 4061篇 |
外国民族医学 | 3篇 |
外科学 | 17361篇 |
综合类 | 1104篇 |
一般理论 | 131篇 |
预防医学 | 8542篇 |
眼科学 | 2163篇 |
药学 | 6864篇 |
中国医学 | 114篇 |
肿瘤学 | 7628篇 |
出版年
2023年 | 625篇 |
2022年 | 1026篇 |
2021年 | 2296篇 |
2020年 | 1427篇 |
2019年 | 2250篇 |
2018年 | 2715篇 |
2017年 | 1956篇 |
2016年 | 2159篇 |
2015年 | 2435篇 |
2014年 | 3649篇 |
2013年 | 4999篇 |
2012年 | 7950篇 |
2011年 | 8336篇 |
2010年 | 4812篇 |
2009年 | 4322篇 |
2008年 | 7472篇 |
2007年 | 7822篇 |
2006年 | 7542篇 |
2005年 | 7241篇 |
2004年 | 7038篇 |
2003年 | 6317篇 |
2002年 | 5955篇 |
2001年 | 1074篇 |
2000年 | 811篇 |
1999年 | 1077篇 |
1998年 | 1286篇 |
1997年 | 991篇 |
1996年 | 822篇 |
1995年 | 736篇 |
1994年 | 636篇 |
1993年 | 613篇 |
1992年 | 568篇 |
1991年 | 515篇 |
1990年 | 423篇 |
1989年 | 383篇 |
1988年 | 359篇 |
1987年 | 358篇 |
1986年 | 309篇 |
1985年 | 342篇 |
1984年 | 383篇 |
1983年 | 298篇 |
1982年 | 365篇 |
1981年 | 309篇 |
1980年 | 245篇 |
1979年 | 134篇 |
1978年 | 155篇 |
1977年 | 120篇 |
1976年 | 107篇 |
1975年 | 80篇 |
1973年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
81.
82.
François Béïque Mohamed Ali Scott MacKenzie Mark Hynes 《Journal canadien d'anesthésie》2007,54(2):158-159
83.
84.
Gillian M Stavro Mark L Ettenhofer Joel T Nigg 《Journal of the International Neuropsychological Society》2007,13(2):324-334
Attention-deficit/hyperactivity disorder (ADHD) is associated with impairments in occupational, social, and educational functioning in adults. This study examined relations of adaptive impairment to ADHD symptom domains (inattentive-disorganized and hyperactive-impulsive) and to deficits in executive functioning (EF) in 195 well-characterized adults (105 ADHD, 90 non-ADHD, between ages 18 and 37). Participants completed a battery of EF measures as well as assessments of adaptive functioning. Confirmatory factor analyses were used to validate latent factors for adaptive functioning and EF. In a measurement model, weaker EF was associated with poorer adaptive functioning (r = -.30). When multi-informant composite variables for current inattentive-disorganized and hyperactive-impulsive ADHD symptoms were included in the structural model, EF no longer predicted adaptive functioning. While both symptom composites were similarly related to EF (inattentive-disorganized r = .36; hyperactive-impulsive r = .29), inattentive-disorganized symptoms accounted for more variance in adaptive functioning (67.2% vs. 3.6%). Furthermore, for retrospectively reported childhood symptoms of ADHD, only the inattentive-disorganized symptom domain was related to EF or adaptive impairment. These results suggest that, in adults with ADHD, inattentive-disorganized symptoms may be the primary contributor to key aspects of poorer adaptive function and may be the behavioral path through which EF deficits lead to adaptive impairment. 相似文献
85.
Aim: To examine the evidence of benefit in initiating immediate chemotherapy in patients with newly diagnosed asymptomatic metastatic incurable cancer, compared with delaying chemotherapy until symptomatic progression. Methods: Through an extensive review of published reports, we examined the biological, clinical, psychological and ethical background of the issue and reported on the available clinical trial evidence in a variety of tumor types. Results: Only a limited number of clinical trials have directly examined the role of immediate versus delayed chemotherapy in patients with incurable asymptomatic metastatic cancer. Small studies in mesothelioma, colorectal cancer, breast cancer, myeloma, and low‐grade lymphoma suggest no survival benefit for the immediate initiation of chemotherapy. However, there was no evidence in other tumor types. Conclusion: The appropriate timing of chemotherapy initiation in an asymptomatic patient with metastatic cancer remains a substantial question in oncology. Many factors are likely to impact on the decision. However, little if any evidence demonstrates a clear advantage in the immediate initiation of chemotherapy in this setting. 相似文献
86.
PURPOSE: The pharmacology of methamphetamine is reviewed, and the effects of methamphetamine use on oral health are described. SUMMARY: Methamphetamine is a highly addictive amphetamine analogue, initially synthesized in 1919. Illicit methamphetamine use leads to devastating effects on health, particularly the dentition. Illegal production of methamphetamine has skyrocketed in recent years, as have the number of users. The chief complaint of methamphetamine users is xerostomia. Without the protective effects of saliva, caries development in these patients is rampant. The typical pattern of decay involves the facial and cervical areas of both the maxillary and mandibular teeth, with eventual progression to frank coronal involvement. The acidic substances used to manufacture this drug have also been implicated as a cause of tooth decay and wear in users, as has bruxism as a result of drug-induced hyperactivity. When possible, these patients should be referred to a dentist to improve their oral health status and minimize the potential for adverse cardiovascular sequelae. Other preventive measures for methamphetamine users include stimulating saliva flow and increasing fluoride supplementation. Pharmacists should also counsel users to avoid carbohydrate-rich soft drinks in favor of water. Oral moisturizers may also be effective. CONCLUSION: Methamphetamine use causes xerostomia secondary to sympathetic central nervous system activation, rampant caries caused by high-sugar intake in the absence of protective saliva, and bruxism as a result of hyperactivity. Practitioners should know how to recognize the signs of and manage the oral health of patients with a history of methamphetamine use. 相似文献
87.
Decisions about which health-care interventions represent adequate value to collectively funded health-care systems are as widespread as they are unavoidable. In the case of new pharmaceuticals, many countries now require formal cost-effectiveness analysis to inform this decision-making process. This requires evidence on parameters associated with health-related utilities, treatment effects, resource use, and costs, for which data from available regulatory trials are invariably absent or highly uncertain. This uncertainty results from a number of factors including the predominance of intermediate end points in the clinical evidence-base and the limited period of follow-up of patients in clinical studies. Despite these imperfections in the evidence base, decisions about whether new pharmaceuticals are sufficiently cost-effective for reimbursement cannot be side-stepped. Data limitations do, however, require the use of rigorous analytical methods to support decision making. Probabilistic decision models and value of information analysis offer a means of structuring decision problems, synthesizing all available data, characterizing the uncertainty in the decision, quantifying the cost of uncertainty, and establishing the expected value of perfect information. This analytical framework is important because it addresses two fundamental questions about new pharmaceuticals. First, is the product expected to be cost-effective on the basis of existing evidence? Second, is additional research concerning the product itself cost-effective? In addressing these questions, the analytical framework can establish when sufficient evidence exists to sustain a claim for a new pharmaceutical to be cost-effective. 相似文献
88.
Stem cells and periodontal regeneration 总被引:10,自引:0,他引:10
89.
90.
Alfred E Buxton Hugh Calkins David J Callans John P DiMarco John D Fisher H Leon Greene David E Haines David L Hayes Paul A Heidenreich John M Miller Athena Poppas Eric N Prystowsky Mark H Schoenfeld Peter J Zimetbaum Paul A Heidenreich David C Goff Frederick L Grover David J Malenka Eric D Peterson Martha J Radford Rita F Redberg 《Journal of the American College of Cardiology》2006,48(11):2360-2396