全文获取类型
收费全文 | 32438篇 |
免费 | 1341篇 |
国内免费 | 91篇 |
专业分类
耳鼻咽喉 | 255篇 |
儿科学 | 1093篇 |
妇产科学 | 915篇 |
基础医学 | 3581篇 |
口腔科学 | 393篇 |
临床医学 | 5844篇 |
内科学 | 5344篇 |
皮肤病学 | 357篇 |
神经病学 | 3139篇 |
特种医学 | 605篇 |
外国民族医学 | 1篇 |
外科学 | 3025篇 |
综合类 | 296篇 |
现状与发展 | 1篇 |
一般理论 | 50篇 |
预防医学 | 4482篇 |
眼科学 | 448篇 |
药学 | 1863篇 |
2篇 | |
中国医学 | 34篇 |
肿瘤学 | 2142篇 |
出版年
2024年 | 116篇 |
2023年 | 205篇 |
2022年 | 327篇 |
2021年 | 606篇 |
2020年 | 442篇 |
2019年 | 694篇 |
2018年 | 805篇 |
2017年 | 558篇 |
2016年 | 634篇 |
2015年 | 670篇 |
2014年 | 986篇 |
2013年 | 1585篇 |
2012年 | 2285篇 |
2011年 | 2419篇 |
2010年 | 1279篇 |
2009年 | 1123篇 |
2008年 | 2185篇 |
2007年 | 2379篇 |
2006年 | 2266篇 |
2005年 | 2201篇 |
2004年 | 2027篇 |
2003年 | 1951篇 |
2002年 | 1867篇 |
2001年 | 217篇 |
2000年 | 184篇 |
1999年 | 279篇 |
1998年 | 371篇 |
1997年 | 309篇 |
1996年 | 244篇 |
1995年 | 274篇 |
1994年 | 214篇 |
1993年 | 210篇 |
1992年 | 131篇 |
1991年 | 136篇 |
1990年 | 134篇 |
1989年 | 112篇 |
1988年 | 103篇 |
1987年 | 94篇 |
1986年 | 92篇 |
1985年 | 105篇 |
1984年 | 124篇 |
1983年 | 126篇 |
1982年 | 144篇 |
1981年 | 141篇 |
1980年 | 118篇 |
1979年 | 56篇 |
1978年 | 71篇 |
1977年 | 61篇 |
1976年 | 47篇 |
1974年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
OBJECTIVE: To identify the incidence of bleeding complications associated with peritoneal dialysis catheter insertion. DESIGN: Retrospective review at a tertiary-care center of all double-cuffed Tenckhoff catheters placed surgically from 1 January 1992 to 1 October 2003 to identify the incidence of major bleeding complications occurring with catheter insertion. Major bleeding episodes were defined as > or = 3% decline in hematocrit, or the need for surgical intervention or blood transfusion within 2 weeks of insertion. RESULTS: 292 catheters had been inserted in 263 patients. Six patients satisfied the criteria for a major bleeding event, for a major bleeding complication rate of 2%. Bleeding was associated with perioperative anticoagulation in 3 patients, uremia and thrombocytopenia in 1 patient, aspirin use and thrombocytopenia in 1 patient, and 1 patient experienced intraoperative bleeding. Coagulation parameters were not obtained prior to the procedure in 2 of the 6 patients. CONCLUSION: The rate of serious bleeding complications related to catheter insertion is low and usually associated with anticoagulation. Holding anticoagulation therapy for a minimum of 24 hours during the postoperative period should eliminate much of the risk. Coagulation parameters should also be obtained and corrected preoperatively. 相似文献
44.
45.
Jeffrey A Morgan Ranjit John Yookyung Park Linda J Addonizio Mehmet C Oz Niloo M Edwards Jan M Quaegebeur Ralph S Mosca 《The Journal of heart and lung transplantation》2005,24(1):58-62
BACKGROUND: Many cardiac transplant programs have liberalized donor eligibility criteria in an attempt to maximize donor supply and to accommodate increasing demand. Although many studies have evaluated the potential adverse effects of prolonged donor ischemic time (DIT) in adults undergoing cardiac transplantation, relatively few have focused specifically on pediatric recipients that include a substantial number of patients and long-term follow-up. The focus of this study was to examine the effect of extended DIT on mortality after pediatric heart transplantation. METHODS: We conducted a retrospective review of our pediatric cardiac transplant experience in the past 11 years, comparing patients who received allografts and had ischemic times >240 minutes with those who had ischemic times <240 minutes. RESULTS: A total of 129 pediatric patients (<19 years) underwent orthotopic heart transplantation, of whom 78 (60.5%) had DIT <240 minutes and 51 (39.5%) had DIT >240 minutes. We found no statistically significant difference in age, sex, race, height, weight, or donor age between the groups (p = not significant). Post-transplant survival at 1, 5, and 10 years was similar for both groups: 91.2%, 88.0%, and 85.2%, respectively, for patients with DIT <240 minutes vs 89.6%, 87.2%, and 79.8%, respectively, for patients with DIT >240 minutes (p = 0.433). Additionally, using Cox proportional hazard models, extended DIT >240 minutes was not a statistically significant independent predictor of post-transplant mortality (odds ratio, 0.655; 95% confidence interval, 0.518-0.972; p = 0.684; standard error = 0.468). CONCLUSION: Procurement of hearts from distant locations with associated extended DIT is justified in the setting of increased demand and a fixed donor population. 相似文献
46.
47.
48.
49.
Jonathan L. Katz Jeffrey M. Witkin Steven I. Dworkin Linda A. Dykstra Richard B. Carter 《Drug development research》1990,20(1):31-41
Effects of daily administrations of d-amphetamine were studied on key peck responses of pigeons maintained under a multiple fixed-interval 2-min, fixed-ratio 30-responseschedule. Under the fixed-interval schedule, a pause was followed by a transition to increasing rates of responding until food presentation. Under the fixed-ratio schedule, higher sustained rates of responding were maintained. Low to intermediate doses (0.3-1.0 mg/kg) of d-amphetamine changed the temporal patterns and occasionally increased rates of responding under the fixed-interval schedule. Higher doses decreased rates of responding under bothschedules. With daily injections of 1.0 mg/kg d-amphetamine prior to experimental sessions, the effects of this dose on rates and patterns of responding were attenuated, and d-anphetamine dose-effect curves were shifted to the right, primarily under the fixed-ratio schedule. Similar results were obtained with daily presession injections of 5.6 mg/kg d-amphetamine in a second group of pigeons, except that rates of responding under both schedules were decreased by this daily dose, and did not return completely to control values with repeated injections. In a third group of pigeons, 1.0 mg/kg d-amphetamine administered daily, after experimental sessions, did not alter dose-effect functions for d-amphetamine. In a second experiment, pigeons were trained to peck one response key when given 1.0 mg/kg d-amphetamine and a different key when given presession water injections. Increasing doses of d-amphetamine produced incresing percentages of d-amphetamine-key responses. Repeated administration of 5.6 mg/kg d-amphetamine shifted these dose-effect functions to the right one-half log unit. Results suggested that decreases in reinforcement frequency are not a necessary condition for the development of behavioral tolerance to d-amphetamine. 相似文献
50.
Danny Lam RMN RNT PGCE Dip in GHGMR BSc BA MSc MA & Linda Cheng RMN RGN RMNS RNT BA Dip in Counselling Supervision 《Journal of advanced nursing》1998,27(6):1143-1150
Research shows that clients with automatic thoughts (dysfunctional thinking) often do not think of alternative explanations in relation to negative events. Furthermore, these automatic thoughts are characterized by a broad global, self-evaluative and ambiguous nature that could make disputing (or changing the ways they think) the most difficult part of the therapeutic process. This paper proposes a two-stage practise-based disputing model, guided by research, that aims to 'bring' an automatic thought to a specific, objective, quantifiable and concrete level at which not only is the particular aspect(s) of the automatic thought that causes emotional disturbances finely focused, but the disputing is also likely to be effective and manageable. Furthermore, it will also generate alternative explanations that are helpful in reducing emotional disturbances and in facilitating problem solving approach. In this paper, the authors use a case example to discuss the rationale that underpins the conceptualization of the model and to illustrate the process in which the strategies of the model are effectively used. 相似文献