首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   921篇
  免费   65篇
  国内免费   7篇
耳鼻咽喉   45篇
儿科学   21篇
妇产科学   18篇
基础医学   147篇
口腔科学   13篇
临床医学   104篇
内科学   167篇
皮肤病学   10篇
神经病学   111篇
特种医学   36篇
外科学   151篇
综合类   4篇
预防医学   41篇
眼科学   27篇
药学   41篇
肿瘤学   57篇
  2024年   2篇
  2023年   14篇
  2022年   31篇
  2021年   63篇
  2020年   29篇
  2019年   47篇
  2018年   52篇
  2017年   31篇
  2016年   33篇
  2015年   28篇
  2014年   38篇
  2013年   44篇
  2012年   86篇
  2011年   75篇
  2010年   37篇
  2009年   23篇
  2008年   43篇
  2007年   44篇
  2006年   43篇
  2005年   29篇
  2004年   16篇
  2003年   21篇
  2002年   21篇
  2001年   5篇
  2000年   4篇
  1999年   11篇
  1998年   7篇
  1997年   5篇
  1996年   6篇
  1995年   10篇
  1994年   5篇
  1993年   3篇
  1992年   13篇
  1991年   11篇
  1990年   5篇
  1989年   8篇
  1988年   9篇
  1987年   2篇
  1985年   5篇
  1984年   4篇
  1982年   2篇
  1981年   2篇
  1980年   3篇
  1979年   2篇
  1978年   3篇
  1977年   4篇
  1974年   4篇
  1940年   1篇
  1925年   1篇
  1904年   1篇
排序方式: 共有993条查询结果,搜索用时 31 毫秒
71.
Measurements of tissue levels of monoamines and their metabolites, and of the rates of 5-hydroxytryptophan and dihydroxy-phenylalanine accumulation after blockade of aromatic amino acid decarboxylase by benserazid indicated that ipsapirone (1-10 mg/kg i.p.) decreased 5-hydroxytryptamine (5-HT) turnover and accelerated dopamine (DA) turnover in various brain regions. The reduced 5-HT turnover probably resulted from the stimulation of 5-HT1A autoreceptors within the anterior raphe nuclei as in vitro tests [( 3H]-8-hydroxy-2-[di-n-propylamino]tetralin binding and adenylate cyclase assays) demonstrated that ipsapirone was a 5-HT1A agonist almost as potent as 8-OH-DPAT, and the same decrease in 5-hydroxytryptophan accumulation could be induced by the i.p. (5 mg/kg) or intraraphe (1 microgram) injection of ipsapirone. Ipsapirone-induced acceleration of DA turnover persisted after the selective degeneration of serotoninergic neurons by intraraphe 5,7-dihydroxytryptamine infusion, and could be reproduced by i.p. administration of other 5-HT1A agonists like buspirone and gepirone, but not 8-OH-DPAT. These results demonstrate that ipsapirone-induced acceleration of DA turnover did not result from the stimulation of 5-HT1A (auto)receptors, but involved additional target(s) of the drug. The possible participation of dopaminergic systems in the "anxiolytic" properties of ipsapirone should deserve further investigations.  相似文献   
72.
Invasive fungal infections have appeared to be increasingly emergent in immunocompromised patients, especially in solid organ transplant (SOT) recipients. The Alternaria genus encompasses more than 80 dematiaceus species. Among them, Alternaria alternata and Alternaria infectoria are the most frequent isolated as responsible for infection in humans.To our knowledge, we report the first case of a heart transplant recipient suffering from subcutaneous nodule caused by Alternaria infectoria and who was treated with isavuconazole. Despite all the promises of this new azole drug, one should keep in mind the potential great variability of the inter-individual responses for such complex patients. We demonstrate herein how it can be challenging to manage Alternaria infection in SOT recipients. More comprehensive studies and recommendations are expected in the context of Alternaria infections.  相似文献   
73.

Objective

To review and analyze periodontal clinical parameters after bariatric surgery.

Background

Periodontitis, a dysbiotic inflammatory disease, has been associated with obesity. The purpose of bariatric surgery is to reduce weight and systemic inflammation. Consequently, it is of interest to systematically review the impact of bariatric surgery on periodontal status.

Methods

Electronic searches were conducted in MEDLINE, EMBASE, Thesis database, and the Cochrane Library databases. Gray literature and the main journals of both specialties were also reviewed. Only cross-sectional and prospective studies focusing on bleeding on probing, pocket depth, and clinical attachment levels were selected.

Results

After a thorough screening of 651 studies, 10 studies were selected by 2 independent reviewers. Four (n?=?250) and 3 studies (n?=?191) were included in the meta-analysis at 6- and 12-month follow-up, respectively. At 6-month follow-up increased periodontal inflammation (P?=?.03) and periodontal destruction were observed. However, 12 months after baseline, the difference between bariatric patients and control was no longer significant.

Conclusion

The present systematic review and meta-analysis suggests that deterioration of periodontal status may be observed in the first 6 months after surgery. Consequently, periodontal screening and management of the patient's request for bariatric surgery should be recommended to avoid further deterioration of periodontal status after bariatric surgery.  相似文献   
74.

Objective

The objective of this study was to evaluate the early and long-term outcome of cryopreserved arterial allografts (CAAs) used for in situ reconstruction of abdominal aortic native or secondary graft infection and to identify predictors of mortality.

Methods

We retrospectively included 71 patients (mean age, 65.2 years [range, 41-84 years]; men, 91.5%) treated for abdominal aortic native or secondary graft infection (65 prosthetic graft infections; 16 of them had secondary aortoenteric fistula, 2 venous graft infections, and 4 mycotic aneurysms) by in situ reconstruction with CAA in the university hospitals of Clermont-Ferrand and Saint-Etienne from 2000 to 2016. The cryopreservation protocol was identical in both centers (?140°C). Early (<30 days) and late (>30 days) mortality and morbidity, reinfection, and CAA patency were assessed. Computed tomography was performed in all survivors. Survival was analyzed with the Kaplan-Meier method. Univariate analyses were performed with the log-rank test and multivariate analysis with the Cox regression model.

Results

Mean follow-up was 45 months (0-196 months). Early postoperative mortality rate was 16.9% (11/71). Early postoperative CAA-related mortality rate was 2.8% (2/71); both patients died of proximal anastomotic rupture on postoperative days 4 and 15. Early CAA-related reintervention rate was 5.6% (4/71); all had an anastomotic rupture, and two were lethal. Early postoperative reintervention rate was 15.5% (11/71). Intraoperative bacteriologic samples were positive in 56.3%, and 31% had a sole microorganism. Escherichia coli was more frequently identified in the secondary aortoenteric fistula and Staphylococcus epidermidis in the infected prosthesis. Late CAA-related mortality rate was 2.8%: septic shock at 2 months in one patient and proximal anastomosis rupture at 1 year in one patient. Survival at 1 year, 3 years, and 5 years was 75%, 64%, and 54%, respectively. Multivariate analysis identified type 1 diabetes (hazard ratio, 2.49; 95% confidence interval, 1.05-5.88; P = .04) and American Society of Anesthesiologists class 4 (hazard ratio, 2.65; 95% confidence interval, 1.07-6.53; P = .035) as predictors of mortality after in situ CAA reconstruction. Reinfection rate was 4% (3/71). Late CAA-related reintervention rate was 12.7% (9/71): proximal anastomotic rupture in one, CAA branch stenosis/thrombosis in five, ureteral-CAA branch fistula in one, and distal anastomosis false aneurysm in two. Primary patency at 1 year, 3 years, and 5 years was 100%, 93%, and 93%, respectively. Assisted primary patency at 1 year, 3 years, and 5 years was 100%, 96%, and 96%, respectively. No aneurysm or dilation was observed.

Conclusions

The prognosis of native or secondary aortic graft infections is poor. Aortic in situ reconstruction with CAA offers acceptable early and late results. Patients with type 1 diabetes and American Society of Anesthesiologists class 4 are at higher risk of mortality.  相似文献   
75.
76.
The potential interaction of CM 57493 [4-(3-trifluoromethyl-phenyl)-1-(2-cyanoethyl)-1,2,3,6-tetrahydropyri din e] with central 5-hydroxytryptamine (5-HT) receptors was assessed using biochemical and electrophysiological tests in the rat and in the cat. In vitro binding assays with rat brain membranes revealed that CM 57493 bound to 5-HT1A sites in a concentration range (pIC50 = 7.1) at least two orders of magnitude lower than that required for its interaction with 5-HT1B/5-HT1D, 5-HT2, 5-HT3 and 5-HTPre sites. The affinity of CM 57493 for 5-HT1A sites labeled by [3H]-8-OH-DPAT in hippocampal membranes was enhanced by Mn++ and reduced by GTP, as expected for an agonist. Like 8-OH-DPAT, CM 57493 inhibited forskolin-activated adenylate cyclase activity in hippocampal homogenates. The inhibitory effects of these two compounds were not additive and were prevented by 5-HT1A antagonists such as spiperone and dl-propranolol. In vivo treatment with CM 57493 decreased the levels of 5-hydroxyindole acetic acid in various brain areas, as observed with other 5-HT1A agonists such as 8-OH-DPAT and ipsapirone. Electrophysiological recording within the dorsal raphe nucleus in chloral hydrate anesthetized rats showed that CM 57493 administration induced a dose-dependent reduction of the spontaneous firing of serotoninergic neurons. In vitro, CM 57493 (5-20 microM) also reduced neuronal firing in the nucleus raphe dorsalis within brainstem slice, and this effect could be prevented by dl-propranolol. Finally, in cats pretreated with reserpine, CM 57493 induced a decrease in ponto-geniculo-occipital activity, which could be antagonized by methiothepin.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
77.
The in vitro activity of a multilamellar liposomal formulation of nystatin (Nyotran) was compared with those of free nystatin and four pharmaceutical preparations of amphotericin B. MICs for 200 isolates of two Aspergillus spp., seven Candida spp., and Cryptococcus neoformans were determined by a broth microdilution adaptation of the method recommended by the National Committee for Clinical Laboratory Standards. Minimum lethal concentrations (MLCs) of the six antifungal preparations were also determined. Both nystatin formulations possessed fungistatic and fungicidal activities against the 10 species tested. Liposomal nystatin appeared to be as active as free nystatin, with MICs and MLCs that were similar to, or lower than, those of the latter. Neither formulation of nystatin was as active as amphotericin B deoxycholate (Fungizone) or amphotericin B lipid complex (Abelcet), but both were more effective than liposomal amphotericin B (AmBisome). Our results suggest that further evaluation of liposomal nystatin is justified.  相似文献   
78.

Purpose

Stress cardiomyopathy is a common life-threatening complication after aneurysmal subarachnoid hemorrhage (SAH). We hypothesized that left ventricular (LV) longitudinal strain alterations assessed with speckle tracking could identify early systolic function impairment.

Methods

This was an observational single-center prospective pilot controlled study conducted in a neuro-intensive care unit. Forty-six patients with severe SAH with a World Federation of Neurological Surgeons grade (WFNS) ≥III were included. Transthoracic echocardiography (TTE) was performed on day 1, day 3, and day 7 after the patient’s admission. A cardiologist blinded to the patient’s management analyzed the LV global longitudinal strain (GLS). The control group comprised normal subjects matched according to gender and age.

Results

On day 1 median (25th–75th percentile) GLS was clearly impaired in SAH patients compared to controls [?16.7 (?18.7/?13.7) % versus ?20 (?22/?19) %, p < 0.0001], whereas LVEF was preserved [65 (59?70) %]. GLS was severely impaired in patients with a WFNS score of V versus III–IV [?15.6 (?16.9/?12.3) % versus ?17.8 (?20.6/?15.8) %, p = 0.008]. Seventeen (37 %) patients had a severe GLS alteration (>?16 %). In these patients, GLS improved from day 1 [?12.4 (?14.8/?10.9) %] to last evaluation [?16.2 (?19/?14.6) %, p = 0.0007] in agreement with the natural evolution of stress cardiomyopathy.

Conclusions

On the basis of LV GLS assessment, we demonstrated for the first time that myocardial alteration compatible with a stress cardiomyopathy is detectable in up to 37 % of patients with severe SAH while LVEF is preserved. GLS could be used for sensitive detection of stress cardiomyopathy. This is critical because cardiac impairment remains a major cause of morbidity and mortality after SAH.
  相似文献   
79.
Sinusoidal obstruction syndrome (SOS), also known as hepatic veno-occlusive disease (VOD), is a serious complication after hematopoietic stem cell transplantation (HSCT). SOS/VOD usually occurs within 3 weeks of HSCT, but the 2016 European Society for Blood and Marrow Transplantation diagnosis criteria have been revised to include late forms. Prophylactic use of defibrotide is recommended in the pediatric setting, but its value remains uncertain in the adult population. We report here a single-center series of 63 adult patients considered at high risk for SOS/VOD who received defibrotide prophylaxis in combination with ursodeoxycholic acid between May 2012 and August 2016. The median duration of defibrotide therapy was 23 days. Bleeding occurred in 14 patients (21.5%). Defibrotide prophylaxis was discontinued in 7 patients (10.8%): 4 cases (6.3%) due to bleeding and 3 cases (4.6%) because of the need for antithrombotic therapy. Overall, SOS/VOD occurred in 4 cases (6.3%) within 21 days after HSCT (days 13 and 14) in 2 cases and late-onset SOS/VOD (days 57 and 58) in the other 2 cases. SOS/VOD was moderate in 1 case, very severe in 3 cases, with 2 deaths related to SOS/VOD. Cumulative incidence of grades II to IV acute graft-versus-host disease and transplant-associated thrombotic microangiopathy were 22.2% and 3.2%, respectively. With a median follow-up of 31 months (range, 10.7 to 60.3), the rates of 2-year overall survival, progression-free survival, incidence of relapse, and nonrelapse mortality were 56.5%, 49%, 28.7%, and 22.3%, respectively. In our experience defibrotide prophylaxis is associated with a low incidence of SOS/VOD after allogeneic HSCT in a high-risk adult population with an acceptable safety profile.  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号