全文获取类型
收费全文 | 47639篇 |
免费 | 3832篇 |
国内免费 | 126篇 |
专业分类
耳鼻咽喉 | 379篇 |
儿科学 | 1945篇 |
妇产科学 | 1296篇 |
基础医学 | 6808篇 |
口腔科学 | 983篇 |
临床医学 | 6544篇 |
内科学 | 9251篇 |
皮肤病学 | 910篇 |
神经病学 | 4811篇 |
特种医学 | 1191篇 |
外科学 | 4141篇 |
综合类 | 512篇 |
一般理论 | 62篇 |
预防医学 | 5787篇 |
眼科学 | 673篇 |
药学 | 2661篇 |
2篇 | |
中国医学 | 55篇 |
肿瘤学 | 3586篇 |
出版年
2024年 | 60篇 |
2023年 | 424篇 |
2022年 | 585篇 |
2021年 | 1270篇 |
2020年 | 942篇 |
2019年 | 1401篇 |
2018年 | 1534篇 |
2017年 | 1210篇 |
2016年 | 1338篇 |
2015年 | 1415篇 |
2014年 | 1804篇 |
2013年 | 2636篇 |
2012年 | 3680篇 |
2011年 | 3780篇 |
2010年 | 2097篇 |
2009年 | 1867篇 |
2008年 | 3080篇 |
2007年 | 3156篇 |
2006年 | 3093篇 |
2005年 | 2907篇 |
2004年 | 2815篇 |
2003年 | 2584篇 |
2002年 | 2324篇 |
2001年 | 375篇 |
2000年 | 266篇 |
1999年 | 326篇 |
1998年 | 568篇 |
1997年 | 431篇 |
1996年 | 378篇 |
1995年 | 357篇 |
1994年 | 294篇 |
1993年 | 287篇 |
1992年 | 189篇 |
1991年 | 165篇 |
1990年 | 148篇 |
1989年 | 123篇 |
1988年 | 135篇 |
1987年 | 112篇 |
1986年 | 101篇 |
1985年 | 109篇 |
1984年 | 104篇 |
1983年 | 107篇 |
1982年 | 141篇 |
1981年 | 128篇 |
1980年 | 108篇 |
1979年 | 63篇 |
1978年 | 74篇 |
1977年 | 53篇 |
1976年 | 53篇 |
1975年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Najat C Daw Wayne L Furman Clinton F Stewart Lisa C Iacono Mark Krailo Mark L Bernstein Janet E Dancey Rose Anne Speights Susan M Blaney James M Croop Gregory H Reaman Peter C Adamson 《Journal of clinical oncology》2005,23(25):6172-6180
PURPOSE: Epidermal growth factor receptor is expressed in pediatric malignant solid tumors. We conducted a phase I trial of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in children with refractory solid tumors. PATIENTS AND METHODS: Gefitinib (150, 300, 400, or 500 mg/m2) was administered orally to cohorts of three to six patients once daily continuously until disease progression or significant toxicity. Pharmacokinetic studies were performed during course one (day 1 through 28). RESULTS: Of the 25 enrolled patients, 19 (median age, 15 years) were fully evaluable for toxicity and received 54 courses. Dose-limiting toxicity was rash in two patients treated with 500 mg/m2 and elevated ALT and AST in one patient treated with 400 mg/m2. The maximum-tolerated dose was 400 mg/m2/d. The most frequent non-dose-limiting toxicities were grade 1 or 2 dry skin, anemia, diarrhea, nausea, and vomiting. One patient with Ewing's sarcoma had a partial response. Disease stabilized for 8 to > or = 60 weeks in two patients with Wilms' tumor and two with brainstem glioma (one exophytic). At 400 mg/m2, the median peak gefitinib plasma concentration was 2.2 microg/mL (range, 1.2 to 3.6 microg/mL) and occurred at a median of 2.3 hours (range, 2.0 to 8.3 hours) after drug administration. The median apparent clearance and median half-life were 14.8 L/h/m2 (range, 3.8 to 24.8 L/h/m2) and 11.7 hours (range, 5.6 to 22.8 hours), respectively. Gefitinib systemic exposures were comparable with those associated with antitumor activity in adults. CONCLUSION: Oral gefitinib is well tolerated in children. Development of the drug in combination with cytotoxic chemotherapy will be pursued. 相似文献
13.
Understanding the minimum clinically important difference: a review of concepts and methods. 总被引:2,自引:0,他引:2
Anne G Copay Brian R Subach Steven D Glassman David W Polly Thomas C Schuler 《The spine journal》2007,7(5):541-546
BACKGROUND CONTEXT: The effectiveness of spinal surgery as a treatment option is currently evaluated through the assessment of patient-reported outcomes (PROs). The minimum clinically important difference (MCID) represents the smallest improvement considered worthwhile by a patient. The concept of an MCID is offered as the new standard for determining effectiveness of a given treatment and describing patient satisfaction in reference to that treatment. PURPOSE: Our goal is to review the various definitions of MCID and the methods available to determine MCID. STUDY DESIGN: The primary means of determining the MCID for a specific treatment are divided into anchor-based and distribution-based methods. Each method is further subdivided and examined in detail. METHODS: The overall limitations of the MCID concept are first identified. The basic assumptions, statistical biases, and shortcomings of each method are examined in detail. RESULTS: Each method of determining the MCID has specific shortcomings. Three general limitations in the accurate determination of an MCID have been identified: the multiplicity of MCID determinations, the loss of the patient's perspective, and the relationship between pretreatment baseline and posttreatment change scores. CONCLUSIONS: An ideal means of determining the MCID for a given intervention is yet to be determined. It is possible to develop a useful method provided that the assumptions and methodology are initially declared. Our efforts toward the establishment of a MCID will rely on the establishment of specific external criteria based on the symptoms of the patient and treatment intervention being evaluated. 相似文献
14.
Acta Endoscopica - C’est un test de sélection. C’est un outil important de communication et d’information, c’est dire si elle doit être connue, comprise et bien... 相似文献
15.
Sylvia J T Jansen Wilma Otten Anne M Stiggelbout 《Journal of clinical oncology》2004,22(15):3181-3190
PURPOSE: Many studies have determined cancer patients' preferences for adjuvant therapy, for example, by asking patients the extent of benefit they would need in order to accept the therapy. However, little is known about the determinants that influence these preferences. Our research goal was to explore which determinants underlie patients' preferences by means of a literature review. METHODS: PubMed searches were conducted to identify studies in which cancer patients' preferences for adjuvant therapy had been elicited by means of a treatment preference instrument. Twenty-three papers were evaluated with regard to reported relationships between preferences and potential determinants. A total of 40 determinants were recorded and classified into one of seven categories: (1) treatment-related determinants, (2) sociodemographic characteristics and current quality of life, (3) clinical characteristics, (4) measurement instrument-related determinants, (5) time-related determinants, (6) cognitive/affective determinants, and (7) specialist-related determinants. Results: The benefit and toxicity of treatment, experience of the treatment, and having dependents (eg, children) living at home were important determinants of patients' preferences. Furthermore, qualitative data suggested that cognitive/affective and specialist-related determinants might have a large impact on patients' treatment preferences. CONCLUSION: Our results show that patients' preferences cannot fully be explained on the basis of treatment-related determinants and patient and clinical characteristics. More research is needed in the area of cognitive/affective and specialist-related determinants because of the lack of quantitative results. Furthermore, we recommend carrying out larger studies in which the (internal) relationships between determinants and preferences are assessed in the context of a cognitive cost-benefit model. 相似文献
16.
OBJECTIVE: Based on recent safety and efficacy data, combined with the known pharmacokinetic parameters of aminoglycosides in the newborn, once-daily gentamicin should be preferable to the many other dosing regimens currently in use. Although there are growing data to support its use in term newborns, experience with preterm infants is more limited. In our Neonatal Intensive Care Unit, we experienced difficulties regarding complicated dosing regimens, actual dosing errors, and the tendency to check trough and peak levels around the third dose for infants receiving only a 48 hour course. Therefore, we conducted a quality improvement initiative in which we developed and tested a clinical practice guideline for the use of once-daily gentamicin for preterm and term infants that we hoped would yield trough and peak levels in our target range. METHODS: We combined a review of the published English language literature with pharmacokinetic analysis of our own data prior to initiation of this new regimen to design the following dosing regimen: <35 weeks gestation: 3 mg/kg q 24 hours, > or =35 weeks gestation: 4 mg/kg q 24 hours. Our goal serum levels were a trough < or =2 microg/ml and a peak between 6 and 12 microg/ml. We collected and analyzed trough and peak levels from all infants receiving this dosing regimen in the first week of life for at least 72 hours between 3/1/99 and 12/31/00. RESULTS: In total, 214 babies met our inclusion criteria, 75 of whom were <35 weeks gestation. 100% of babies of all gestational ages had a nontoxic trough level. For infants <35 weeks gestation, 79% had a therapeutic peak level, with a mean value of 6.8 microg/ml. For infants of at least 35 weeks gestation, 93% had a therapeutic peak level, with a mean value of 8.4 microg/ml. 92% of nontherapeutic peaks were too low. CONCLUSION: This study of once-daily gentamicin represents the largest sample size of pre-term infants published to date. The proposed regimen is simple and yields a high proportion of desirable levels. We recommend it for use in preterm and term newborns. 相似文献
17.
18.
Anthropology, and its supposed operationalisation within transcultural nursing, is becoming increasingly prominent in educational curricula in the U.K. This increase in interest is driven both by governmental pressure to provide more culturally appropriate care, and an intuitive notion that anthropology, nursing and other related professions such as midwifery have a common basis of mutually overlapping and re-enforcing theory and practice. This paper explores the question of whether there is a natural alliance between anthropology, and the applied aspects of health care disciplines such as nursing and midwifery, by examining some of the concepts underlying each discipline, and the ways in which these concepts are applied in practice. Anthropology is the study of culture, and it is suggested that a more complete understanding of this central concept is essential if it is to be utilised in the applied disciplines encompassed by the practice of nursing and midwifery. 相似文献
19.
Dr. Andrew G. Bostom M.D. Dr. Anne L. Hume Pharm.D. Dr. Charles B. Eaton M.D. Dr. Joseph P. Laurino Ph.D. Ms. Lisa R. Yanek B.A. Ms. Mary S. Regan B.S. Mr. William H. McQuade M.P.H. Dr. Wendy Y. Craig Ph.D. Ms. Gayle Perrone M.B.A. Dr. Paul F. Jacques Sc.D. 《Pharmacotherapy》1995,15(4):458-464
Study Objective . To determine the efficacy of high-dose ascorbate supplementation in lowering lipoprotein(a) [Lp(a)] levels in patients with premature coronary heart disease (CHD). Design . Randomized, double-blind, placebo-controlled trial. Setting . Outpatient clinic. Patients . Forty-four patients with documented premature CHD. defined as confirmed myocardial infarction and/or angiographically determined stenosis of 50% or greater in at least one major coronary artery before age 60 years. Interventions . Patients were block randomized on the basis of age, gender, and screening Lp(a) concentrations to receive ascorbate 4.5 g/day or placebo for 12 weeks. Measurements and Main Results . High-dose ascorbate was well tolerated and produced a marked elevation in mean plasma ascorbate levels (+1.2 mg/dl; p<0.001). Multiple linear regression analysis revealed no significant effect of supplementation on postintervention Lp(a) levels (p=0.39) in a model that included treatment group assignment, and baseline Lp(a) levels. Conclusions . Our findings do not support a clinically important lowering effect of high-dose ascorbate on plasma Lp(a) in patients with premature CHD. 相似文献
20.
ANAPHYLAXIS IS A SEVERE SYSTEMIC ALLERGIC reaction that is potentially fatal. It requires prompt recognition and immediate management. Anaphylaxis has a rapid onset with multiple organ–system involvement and is mostly caused by specific antigens in sensitized individuals. Reactions typically follow a uniphasic course, however, 20% will be biphasic in nature. The second phase usually occurs after an asymptomatic period of 1–8 hours, but there may be a 24-hour delay. Protracted anaphylaxis may persist beyond 24 hours. Concurrent β-blocker therapy may adversely affect the response to management. Epinephrine is the treatment of choice and should be administered immediately. Secondary measures include circulatory support, H1 and H2 antagonists, corticosteroids and, occasionally, bronchodilators. Post-treatment observation of these patients is necessary, and they should remain within ready access of emergency care for the following 48 hours. 相似文献