全文获取类型
收费全文 | 987篇 |
免费 | 98篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 75篇 |
妇产科学 | 31篇 |
基础医学 | 92篇 |
口腔科学 | 36篇 |
临床医学 | 165篇 |
内科学 | 214篇 |
皮肤病学 | 27篇 |
神经病学 | 47篇 |
特种医学 | 156篇 |
外科学 | 72篇 |
综合类 | 25篇 |
预防医学 | 60篇 |
眼科学 | 12篇 |
药学 | 52篇 |
1篇 | |
中国医学 | 9篇 |
肿瘤学 | 51篇 |
出版年
2023年 | 2篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 21篇 |
2017年 | 23篇 |
2016年 | 26篇 |
2015年 | 29篇 |
2014年 | 36篇 |
2013年 | 43篇 |
2012年 | 17篇 |
2011年 | 28篇 |
2010年 | 41篇 |
2009年 | 67篇 |
2008年 | 28篇 |
2007年 | 48篇 |
2006年 | 19篇 |
2005年 | 26篇 |
2004年 | 11篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2001年 | 21篇 |
2000年 | 14篇 |
1999年 | 24篇 |
1998年 | 70篇 |
1997年 | 81篇 |
1996年 | 57篇 |
1995年 | 51篇 |
1994年 | 37篇 |
1993年 | 43篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 26篇 |
1988年 | 22篇 |
1987年 | 27篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1978年 | 5篇 |
1977年 | 11篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1934年 | 1篇 |
1931年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有1131条查询结果,搜索用时 22 毫秒
11.
Kidney transplants in mice. An analysis of the immune status of mice bearing long-term, H-2 incompatible transplants 下载免费PDF全文
Kidney transplants between strains of mice which are incompatible at either the K or the D end of the H-2 complex usually function for prolonged periods supporting the lives of nephrectomized recipients. This occurs with no recipient treatment. With multiple H-2 and non-H-2 determined incompatibilities, transplants may be rejected but more slowly than skin grafts. In the strain combination studied most extensively in these experiments (B10.D2 to B6AF(1)) in which the incompatibility was confined to the K end of the H-2 region, about 70 percent of recipients survived for many weeks with normal blood urea nitrogen levels. Skin grafts between untreated members of these strains were rejected promptly (mean survival time of 13.5 +/- 1.1 days) as were kidney transplants to recipients of prior skin grafts. Donor strain skin grafts to recipients of kidney transplants after kidney transplantation enjoyed greatly prolonged survival whereas skin grafts from a third party (A.SW) were rejected normally. If kidney tissue was transferred in the form of free grafts without primary vascular union, it was rejected promptly leaving its recipient highly immunized. Cellular and humoral immunity to donor antigens declined over the first few weeks after transplantation, and the spleens of long-term recipients contained no “killer cells.” Recipient lymphoid cells could mount active graft versus host reactions to donor strain antigens on transfer to neonatal mice. Nevertheless, they were distinctly less able to respond specifically by the production of killer cells to donor strain antigens after sensitization in vitro. No evidence that this defect was associated with the presence of suppressor cells was forthcoming from several types of in vivo and in vitro tests. 相似文献
12.
Randomized, Controlled Trial of Inhaled Budesonide as an Adjunct to Oral Prednisone in Acute Asthma 总被引:1,自引:2,他引:1
Lillian Sung MD Martin H. Osmond MD CM Terry P. Klassen MD 《Academic emergency medicine》1998,5(3):209-213
Objective: To compare the clinical effect of nebulized budesonide with placebo in acute pediatric asthma.
Methods: A randomized, controlled, double-blind trial with parallel design was used in the ED of a tertiary care children's hospital. Children aged 6 months to 18 years with a moderate to severe exacerbation of asthma [Pulmonary Index Score (PIS) ≥5 or ≤11 after a salbutamol nebulization of 0.15 mg/kg] were eligible. All patients received prednisone 1 mg/kg orally and nebulized salbutamol (0.15 mg/kg) every 30 minutes for 3 doses and then every hour for 4 hours. The intervention was 2 mg (4 mL) of nebulized budesonide or 4 mL of nebulized normal saline.
Results: Baseline characteristics were comparable in the budesonide group ( n = 24) and in the placebo group ( n - 20). There were no significant differences in the primary outcome measure (PIS) between the 2 groups. However, the PIS at 1 hour had a tendency to be lower in the budesonide group (median = 5) as compared with the placebo group (median = 6; p = 0.07). Survival analysis of release/discharge from the ED/hospital showed a more rapid rate in the budesonide group as compared with the placebo group (p = 0.02). No adverse effects were seen.
Conclusion: Although these preliminary results suggest that nebulized budesonide may be an effective adjunct to oral prednisone in the management of moderate to severe asthma exacerbations, a larger trial will be required before the widespread use of inhaled budesonide in acute asthma can be advocated. 相似文献
Methods: A randomized, controlled, double-blind trial with parallel design was used in the ED of a tertiary care children's hospital. Children aged 6 months to 18 years with a moderate to severe exacerbation of asthma [Pulmonary Index Score (PIS) ≥5 or ≤11 after a salbutamol nebulization of 0.15 mg/kg] were eligible. All patients received prednisone 1 mg/kg orally and nebulized salbutamol (0.15 mg/kg) every 30 minutes for 3 doses and then every hour for 4 hours. The intervention was 2 mg (4 mL) of nebulized budesonide or 4 mL of nebulized normal saline.
Results: Baseline characteristics were comparable in the budesonide group ( n = 24) and in the placebo group ( n - 20). There were no significant differences in the primary outcome measure (PIS) between the 2 groups. However, the PIS at 1 hour had a tendency to be lower in the budesonide group (median = 5) as compared with the placebo group (median = 6; p = 0.07). Survival analysis of release/discharge from the ED/hospital showed a more rapid rate in the budesonide group as compared with the placebo group (p = 0.02). No adverse effects were seen.
Conclusion: Although these preliminary results suggest that nebulized budesonide may be an effective adjunct to oral prednisone in the management of moderate to severe asthma exacerbations, a larger trial will be required before the widespread use of inhaled budesonide in acute asthma can be advocated. 相似文献
13.
Marleen Straat Marcella CA Müller Joost CM Meijers Mendi S Arbous Angelique ME Spoelstra - de Man Charlotte JP Beurskens Margreeth B Vroom Nicole P Juffermans 《Critical care (London, England)》2015,19(1)
IntroductionMuch controversy exists on the effect of a fresh frozen plasma (FFP) transfusion on systemic inflammation and endothelial damage. Adverse effects of FFP have been well described, including acute lung injury. However, it is also suggested that a higher amount of FFP decreases mortality in trauma patients requiring a massive transfusion. Furthermore, FFP has an endothelial stabilizing effect in experimental models. We investigated the effect of fresh frozen plasma transfusion on systemic inflammation and endothelial condition.MethodsA prospective predefined substudy of a randomized trial in coagulopathic non-bleeding critically ill patients receiving a prophylactic transfusion of FFP (12 ml/kg) prior to an invasive procedure. Levels of inflammatory cytokines and markers of endothelial condition were measured in paired samples of 33 patients before and after transfusion. The statistical tests used were paired t test or the Wilcoxon signed-rank test.ResultsAt baseline, systemic cytokine levels were mildly elevated in critically ill patients. FFP transfusion resulted in a decrease of levels of TNF-α (from 11.3 to 2.3 pg/ml, P = 0.01). Other cytokines were not affected. FFP also resulted in a decrease in systemic syndecan-1 levels (from 675 to 565 pg/ml, P = 0.01) and a decrease in factor VIII levels (from 246 to 246%, P <0.01), suggestive of an improved endothelial condition. This was associated with an increase in ADAMTS13 levels (from 24 to 32%, P <0.01) and a concomitant decrease in von Willebrand factor (vWF) levels (from 474 to 423%, P <0.01).ConclusionsA fixed dose of FFP transfusion in critically ill patients decreases syndecan-1 and factor VIII levels, suggesting a stabilized endothelial condition, possibly by increasing ADAMTS13, which is capable of cleaving vWF.
Trial registrations
Trialregister.nl NTR2262, registered 26 March 2010 and Clinicaltrials.gov , registered 14 June 2010. NCT01143909相似文献14.
Nicola Diviani Bas van den Putte Stefano Giani Julia CM van Weert 《Journal of medical Internet research》2015,17(5)
Background
Recent years have witnessed a dramatic increase in consumer online health information seeking. The quality of online health information, however, remains questionable. The issue of information evaluation has become a hot topic, leading to the development of guidelines and checklists to design high-quality online health information. However, little attention has been devoted to how consumers, in particular people with low health literacy, evaluate online health information.Objective
The main aim of this study was to review existing evidence on the association between low health literacy and (1) people’s ability to evaluate online health information, (2) perceived quality of online health information, (3) trust in online health information, and (4) use of evaluation criteria for online health information.Methods
Five academic databases (MEDLINE, PsycINFO, Web of Science, CINAHL, and Communication and Mass-media Complete) were systematically searched. We included peer-reviewed publications investigating differences in the evaluation of online information between people with different health literacy levels.Results
After abstract and full-text screening, 38 articles were included in the review. Only four studies investigated the specific role of low health literacy in the evaluation of online health information. The other studies examined the association between educational level or other skills-based proxies for health literacy, such as general literacy, and outcomes. Results indicate that low health literacy (and related skills) are negatively related to the ability to evaluate online health information and trust in online health information. Evidence on the association with perceived quality of online health information and use of evaluation criteria is inconclusive.Conclusions
The findings indicate that low health literacy (and related skills) play a role in the evaluation of online health information. This topic is therefore worth more scholarly attention. Based on the results of this review, future research in this field should (1) specifically focus on health literacy, (2) devote more attention to the identification of the different criteria people use to evaluate online health information, (3) develop shared definitions and measures for the most commonly used outcomes in the field of evaluation of online health information, and (4) assess the relationship between the different evaluative dimensions and the role played by health literacy in shaping their interplay. 相似文献15.
Decision aids for localized prostate cancer treatment choice: Systematic review and meta‐analysis 下载免费PDF全文
Philippe D. Violette MD CM Thomas Agoritsas MD Paul Alexander MSc MHSc Jarno Riikonen MD PhD Henrikki Santti MD PhD Arnav Agarwal BHSc Neera Bhatnagar MLIS Philipp Dahm MD MHSc Victor Montori MD MSc Gordon H. Guyatt MD MSc Kari A. O. Tikkinen MD PhD 《CA: a cancer journal for clinicians》2015,65(3):239-251
Patients who are diagnosed with localized prostate cancer need to make critical treatment decisions that are sensitive to their values and preferences. The role of decision aids in facilitating these decisions is unknown. The authors conducted a systematic review of randomized trials of decision aids for localized prostate cancer. Teams of 2 reviewers independently identified, selected, and abstracted data from 14 eligible trials (n = 3377 men), of which 10 were conducted in North America. Of these, 11 trials compared decision aids with usual care, and 3 trials compared decision aids with other decision aids. Two trials suggested a modest positive impact on decisional regret. Results across studies varied widely for decisional conflict (4 studies), satisfaction with decision (2 studies), and knowledge (2 studies). No impact on treatment choices was observed (6 studies). In conclusion, scant evidence at high risk of bias suggests the variable impact of existing decision aids on a limited set of decisional processes and outcomes. Because current decision aids provide information but do not directly facilitate shared decision making, subsequent efforts would benefit from user‐centered design of decision aids that promote shared decision making. CA Cancer J Clin 2015;65: 239–251. © 2015 American Cancer Society. 相似文献
16.
CL Sanchez CS Biskup S Herpertz TJ Gaber CM Kuhn SH Hood FD Zepf 《The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP)》2015,18(10)
The neurotransmitters serotonin and dopamine both have a critical role in the underlying neurobiology of different behaviors. With focus on the interplay between dopamine and serotonin, it has been proposed that dopamine biases behavior towards habitual responding, and with serotonin offsetting this phenomenon and directing the balance toward more flexible, goal-directed responding. The present focus paper stands in close relationship to the publication by Worbe et al. (2015), which deals with the effects of acute tryptophan depletion, a neurodietary physiological method to decrease central nervous serotonin synthesis in humans for a short period of time, on the balance between hypothetical goal-directed and habitual systems. In that research, acute tryptophan depletion challenge administration and a following short-term reduction in central nervous serotonin synthesis were associated with a shift of behavioral performance towards habitual responding, providing further evidence that central nervous serotonin function modulates the balance between goal-directed and stimulus-response habitual systems of behavioral control. In the present focus paper, we discuss the findings by Worbe and colleagues in light of animal experiments as well as clinical implications and discuss potential future avenues for related research. 相似文献
17.
18.
19.
20.
Dr. David K. Driman MB ChB FRCPC Cheryl Wright MD FRCPC Gervais Tougas MD CM FRCPC Robert H. Riddell MD FRCPC 《Digestive diseases and sciences》1996,41(10):2039-2047
While there is evidence that omeprazole may induce changes in parietal cells, the effect of acid suppression on parietal cells in humans is poorly documented. This study was undertaken to evaluate the effects of omeprazole in human parietal cells over time. The light microscopic morphology of parietal cells in gastric biopsies from 17 patients on omeprazole were compared with those from 13 patients on ranitidine and 20 patients on no acid-lowering medication. Light microscopic and ultrastructural morphology of parietal cells was also evaluated in an additional 14 patients before and after omeprazole administration. Objective measurements of parietal cell height, mass and number were analyzed using analyses of variance. Electron microscopy was used to evaluate parietal cell enlargement. Twenty-five of 31 biopsies from patients on omeprazole, 1 of 13 from patients on ranitidine, and 0 of 20 from patients on neither drug showed parietal cell enlargement. Parietal cell height, mass, and number were increased in omeprazole-treated patients compared with ranitidine-treated patients and those on neither drug, and with the group also evaluated prior to beginning omeprazole treatment. Parietal cell height and mass were increased in patients on omeprazole longer than 12 months compared with biopsies from patients on the drug for less than 12 months. Resin-embedded sections and electron microscopy showed enlarged parietal cells with prominence of cytoplasmic tubulovesicles with sparse secretory canaliculi. Parietal cell hypertrophy and hyperplasia develops in patients on chronic omeprazole therapy; this can be recognized on routine examination of histologic sections. These morphologic changes increase with duration of therapy. 相似文献