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   1918篇
  免费   123篇
  国内免费   6篇
耳鼻咽喉   27篇
儿科学   48篇
妇产科学   35篇
基础医学   163篇
口腔科学   17篇
临床医学   195篇
内科学   481篇
皮肤病学   33篇
神经病学   57篇
特种医学   81篇
外科学   414篇
综合类   35篇
一般理论   1篇
预防医学   113篇
眼科学   107篇
药学   110篇
中国医学   12篇
肿瘤学   118篇
  2024年   6篇
  2023年   21篇
  2022年   65篇
  2021年   94篇
  2020年   63篇
  2019年   83篇
  2018年   70篇
  2017年   46篇
  2016年   46篇
  2015年   67篇
  2014年   86篇
  2013年   96篇
  2012年   128篇
  2011年   128篇
  2010年   94篇
  2009年   87篇
  2008年   117篇
  2007年   129篇
  2006年   113篇
  2005年   87篇
  2004年   96篇
  2003年   72篇
  2002年   53篇
  2001年   26篇
  2000年   29篇
  1999年   28篇
  1998年   15篇
  1997年   8篇
  1996年   6篇
  1995年   7篇
  1994年   2篇
  1993年   3篇
  1992年   7篇
  1991年   5篇
  1990年   6篇
  1989年   2篇
  1987年   7篇
  1986年   10篇
  1984年   5篇
  1982年   4篇
  1980年   3篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1970年   6篇
  1969年   1篇
  1968年   2篇
  1963年   1篇
  1935年   1篇
  1927年   2篇
排序方式: 共有2047条查询结果,搜索用时 14 毫秒
91.
Monoamines are implicated in a cognitive processes in a variety of brain regions, including the hippocampal formation, where storage and retrieval of information are facilitated by synchronous network activities. We have investigated the effects of norepinephrine, serotonin, and dopamine on carbachol‐, kainate‐, and stimulus‐induced hippocampal γ‐oscillations employing combined extra‐ and intracellular recordings. Monoamines dose‐dependently and reversibly suppressed kainate‐ and carbachol‐induced γ‐oscillations while increasing the frequency. The effect of serotonin was mimicked by fenfluramine, which releases serotonin from presynaptic terminals. Forskolin also suppressed kainate‐ and carbachol‐induced γ‐oscillations. This effect was mimicked by 8‐Br‐cAMP and isoproterenol, an agonist of noradrenergic β‐receptor suggesting that the monoamines‐mediated suppression of these oscillations could involve intracellular cyclic adenosine 3′,5′‐cyclic monophosphate (AMP). By contrast, stimulus‐induced γ‐oscillations were dose‐dependently augmented in power and duration after monoamines application. Intracellular recordings from pyramidal cells revealed that monoamines prolonged the stimulus‐induced depolarization and membrane potential oscillations. Stimulus‐induced γ‐oscillations were also suppressed by isoproterenol, the D1 agonist SKF‐38393 forskolin, and 8‐Br‐cAMP. This suggests that the augmentation of stimulus‐induced γ‐oscillations by monoamines involves—at least in part—different classes of cells than in case of carbachol‐ and kainate‐induced γ‐oscillations. © 2009 Wiley‐Liss, Inc.  相似文献   
92.

Objective

To assess the efficacy of intravaginal electrical stimulation in the management of female urinary incontinence.

Study design

359 Women with urinary incontinence (207 with stress incontinence [group A], 33 with urge incontinence [group B] and 119 with mixed urinary incontinence [group C]) were included in this multicenter prospective observational study. Patients were managed by home intravaginal electrical stimulation of the pelvic floor for 20–30 min per day, 5 days a week, for a period of 10 weeks. Identical clinical assessments were performed before and after pelvic floor rehabilitation, comprising a voiding diary and validated symptom and quality of life scores.

Results

Objective assessment demonstrated an overall cure rate of 63.5% (228/359): 65.7% (136/207) for group A, 57.6% (19/33) for group B, and 61.3% (73/119) for group C. The overall significant improvement rate was 15.6% (56/359): 14.6% (30/207) for group A, 24.2% (8/33) for group B and 15.1% (18/119) for group C. All domains of quality of life were significantly improved after pelvic floor muscle training (p < 0.0001) with a patient satisfaction rate of 83.6%. Treatment was well tolerated with 1.4% (5/359) of patients describing pain at the highest stimulation intensities. No significant difference was observed between the various types of electrodes used (p < 0.0001).

Conclusion

The quantitative and qualitative efficacy in terms of social and psychological consequences and quality of life of home pelvic floor muscle training stimulators probably make this treatment modality one of the first-line treatments for female stress urinary incontinence.  相似文献   
93.
European Journal of Orthopaedic Surgery & Traumatology - A jammed screw is a well-known complication of locking plates. Noncompliance to the standard techniques, nonusage of torque limiting...  相似文献   
94.
95.

Purpose

Although nail dynamization in femoral and tibial fractures is an effective method of promoting healing, its role beyond twelve weeks is still not clear. It is usually done two to three months following interlocking nailing. This study was done to evaluate the efficacy of late dynamization (after 12 weeks) and factors affecting union.

Materials and methods

In this retrospective study, thirty seven patients who underwent dynamization for reamed intramedullary interlocking nails of femur (18) and tibia (20) after twelve weeks from index surgery and with a minimum followup of six months were included. Fracture healing index was calculated using predynamization radiographs. Radiographic union was defined as osseous bridging of three cortices on followup radiographs. Dynamization failure was defined as fractures not showing progressive increase in callus on followup radiographs and those that required secondary intervention.

Results

Mean age of patients at time of injury was 35.92 years (range: 16–63) with males (86.8%) predominating. Mean time to dynamization from index surgery was 19.11 weeks (range-12–36). Thirty one fractures (81.5%) went onto union after dynamization of which twelve were femoral and nineteen were tibial fractures. Mean time to union after dynamization was 6 months. Communited fractures (6–21) showed poor results with delayed dynamization compared to other anatomical types which was statistically significant (P?=?0.05). Predynamization FHI of more than 1.18 had 83% sensitivity and 72% specificity in predicting fracture healing after dynamization.

Conclusion

Late dynamization is still beneficial in promoting healing in femoral and tibial fractures. Communited fractures showed poor results with dynamization. Predynamization FHI was an important predictor of fracture healing.  相似文献   
96.
Focal uptake of 99mTc-MDP was seen in a case of hepatoblastoma. The focal uptake corresponded to an area of calcification on CT, which was shown histologically to consist of osteoid with mineralization. The mechanism of uptake by the tumor in this case is likely to be the same as for skeletal uptake.  相似文献   
97.
Oral contrast medium in PET/CT: should you or shouldn’t you?   总被引:2,自引:0,他引:2  
Purpose It has been suggested that the use of computed tomography (CT) positive contrast agents has led to attenuation-induced artefacts on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT) systems. Consequently, centres may withhold the use of such agents. Whilst there is theoretical evidence to support the aforementioned claim, the clinical relevance of the induced artefacts has not been widely established. Moreover, the potential benefits of bowel enhancement on PET/CT have yet to be formally evaluated. We therefore prospectively examined PET/CT studies to assess whether the use of oral contrast medium induces clinically relevant artefacts and whether the use of these agents is diagnostically helpful.Methods Over a 2-month period, 18F-FDG PET/CT images were prospectively reviewed from 200 patients following Gastrografin administration 2 h prior to examination. Both a radiologist and a nuclear medicine physician reviewed the images for contrast medium-mediated clinically relevant artefacts. Artefacts were sought on the CT attenuation-corrected images and were compared with the appearance on non-attenuated-corrected images. The number of examinations in which the oral contrast aided image interpretation was also noted.Results There were no oral contrast medium-induced clinically significant artefacts. In 38 of the 200 patients, oral contrast aided image interpretation (owing to differentiation of mass/node from bowel, discrimination of intestinal wall from lumen or definition of the anatomy of a relevant site). In 33 of these 38 patients, the anatomical site of interest was the abdomen/pelvis.Conclusion The use of oral contrast medium in 18F-FDG PET studies should not be withheld as it improves image interpretation and does not produce clinically significant artefacts.  相似文献   
98.
The McMaster University 3 MV KN Van de Graff accelerator facility primarily dedicated to in vivo neutron activation measurements has been used to produce moderate dose rates of monoenergetic fast neutrons of energy ranging from 150 to 600 keV with a small energy spread of about 25 keV (1σ width of Gaussian) by bombarding thin lithium targets with 2.00–2.40 MeV protons. The calculated dose rate of the monoenergetic neutrons produced using thin lithium targets as functions of beam energy, target thickness, lab angle relative to beam direction, and the solid angle subtended by the sample with the target has also been reported.  相似文献   
99.
Objective: To evaluate the effectiveness of Judet''s quadricepsplasty for treatment of knee contractures and to identify the effect of local infiltration of epinephrine on blood loss associated with this procedure.Methods: A retrospective cohort study was conducted in which all cases of knee contractures managedwith Judet''s quadricepsplasty from 1st January 2009 to 31st December 2013 were included and weredivided into two groups. The epinephrine group included patients who were infiltrated with dilutedepinephrine (1:400,000) along with xylocaine, around the operative field 15 min prior to the incisiontime, while the control group did not receive any infiltration. Judet''s outcome, blood loss, drop in hemoglobin and required blood transfusion were noted for all patients and compared between both groups.Results: Most common preceding pathology identified for the development of knee contractures wasperiarticular fracture while ilizarov application was the most common etiology. Both groups were found similar in all preoperative characteristics except preoperative flexion contracture (p=0.02). All functional outcome measures including Judet''s outcome were similar in both groups. In contrast, duration of surgery (p=0.01), blood loss (p=0.02), drop in hemoglobin (p=0.01) and number of transfusions (p=0.03) were significantly reduced in epinephrine group.Conclusion: Judet''s quadricepsplasty is a useful procedure to increase the range of motion of rigid knees and local infiltration of epinephrine is effective in decreasing the amount of subsequent blood loss and transfusion requirements.  相似文献   
100.
Bacteriophage therapy (BT) uses bacteriophages to treat pathogenic bacteria and is an emerging strategy against multidrug‐resistant (MDR) infections. Experience in solid organ transplant is limited. We describe BT in 3 lung transplant recipients (LTR) with life‐threatening MDR infections caused by Pseudomonas aeruginosa (n = 2) and Burkholderia dolosa (n = 1). For each patient, lytic bacteriophages were selected against their bacterial isolates. BT was administered for variable durations under emergency Investigational New Drug applications and with patient informed consent. Safety was assessed using clinical/laboratory parameters and observed clinical improvements described, as appropriate. All patients received concurrent antibiotics. Two ventilator‐dependent LTR with large airway complications and refractory MDR P. aeruginosa pneumonia received BT. Both responded clinically and were discharged from the hospital off ventilator support. A third patient had recurrent B. dolosa infection following transplant. Following BT initiation, consolidative opacities improved and ventilator weaning was begun. However, infection relapsed on BT and the patient died. No BT‐related adverse events were identified in the 3 cases. BT was well tolerated and associated with clinical improvement in LTRs with MDR bacterial infection not responsive to antibiotics alone. BT may be a viable adjunct to antibiotics for patients with MDR infections.  相似文献   
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