全文获取类型
收费全文 | 5198篇 |
免费 | 238篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 411篇 |
妇产科学 | 57篇 |
基础医学 | 451篇 |
口腔科学 | 243篇 |
临床医学 | 392篇 |
内科学 | 962篇 |
皮肤病学 | 164篇 |
神经病学 | 403篇 |
特种医学 | 201篇 |
外科学 | 785篇 |
综合类 | 87篇 |
一般理论 | 1篇 |
预防医学 | 215篇 |
眼科学 | 216篇 |
药学 | 380篇 |
中国医学 | 26篇 |
肿瘤学 | 417篇 |
出版年
2024年 | 5篇 |
2023年 | 37篇 |
2022年 | 74篇 |
2021年 | 185篇 |
2020年 | 85篇 |
2019年 | 136篇 |
2018年 | 155篇 |
2017年 | 137篇 |
2016年 | 152篇 |
2015年 | 187篇 |
2014年 | 270篇 |
2013年 | 322篇 |
2012年 | 502篇 |
2011年 | 531篇 |
2010年 | 276篇 |
2009年 | 221篇 |
2008年 | 321篇 |
2007年 | 320篇 |
2006年 | 267篇 |
2005年 | 284篇 |
2004年 | 251篇 |
2003年 | 188篇 |
2002年 | 177篇 |
2001年 | 27篇 |
2000年 | 21篇 |
1999年 | 36篇 |
1998年 | 37篇 |
1997年 | 23篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 16篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 4篇 |
排序方式: 共有5450条查询结果,搜索用时 12 毫秒
21.
22.
Punit Sharma Sachin Jain Sellam Karunanithi Sujoy Pal Pramod Kumar Julka Sanjay Thulkar Arun Malhotra Chandrasekhar Bal Rakesh Kumar 《European journal of nuclear medicine and molecular imaging》2014,41(6):1084-1092
Purpose
To evaluate the role of 18F-FDG PET/CT in the detection of recurrence in patients with oesophageal carcinoma, suspected clinically or following conventional investigations.Methods
This was a retrospective study. Data from 180 patients (age 56.3?±?10.4 years; 126 men, 54 women) with histopathologically proven oesophageal carcinoma (squamous cell 115, adenocarcinoma 59, neuroendocrine carcinoma 4, small cell 1, poorly differentiated 1) who had undergone 227 18F-FDG PET/CT studies for suspected recurrence were analysed. Recurrence was suspected clinically or following conventional investigations. PET/CT images were revaluated by two nuclear medicine physicians in consensus. Findings were grouped into local, nodal and distant recurrence. Results were compared to those from contrast-enhanced (CE) CT when available (109 patients). Clinical/imaging follow-up (minimum 6 months) with histopathology (when available) was taken as the reference standard.Results
Of the 227 18F-FDG PET/CT studies,166 were positive and 61 were negative for recurrent disease. PET/CT showed local recurrence in 134, nodal recurrence in 115 and distant recurrence in 47, with more than one site of recurrence in 34. The PET/CT findings were true-positive in 153 studies, true-negative in 54, false-positive in 13 and false-negative in 7. The sensitivity of 18F-FDG PET/CT was 96 %, the specificity was 81 %, the positive and negative predictive values were 92 % and 89 %, respectively, and the accuracy was 91 %. PET/CT showed similar accuracy in patients with squamous cell carcinoma and in those with adenocarcinoma (P?=?0.181).18F-FDG PET/CT was more specific than CECT (67 % vs. 21 %; P?<?0.0001). PET/CT was superior to CECT for the detection of nodal recurrence (P?<?0.0001), but not local recurrence (P?=?0.093) or distant metastases (P?=?0.441).Conclusion
18F-FDG PET/CT shows high accuracy in the detection of suspected recurrence in patients with oesophageal carcinoma. It is more specific than and is superior to CECT in the detection of nodal recurrence. 相似文献23.
The incidence of traumatic hip dislocation has increased in recent years as a result of high-energy trauma. Anterior hip dislocation forms less than 10-15% of all traumatic hip dislocations. Only a few case reports describe anterior dislocation along with acetabular fractures. The acetabular fracture involved the anterior wall or column in all such cases. We describe a rare case in which anterior superior dislocation of the hip was associated with a large fracture fragment of theposterior acetabular rim and adjacent wall. 相似文献
24.
Robert Sabbagh Suman Chatterjee Arun Chawla Anil Kapoor Edward D. Matsumoto 《Canadian Urological Association journal》2009,3(1):22-30
Background
Performing a laparoscopic urethrovesical anastomosis (LUA) after a radical prostatectomy is technically challenging for the novice laparoscopic surgeon. We developed a low-fidelity urethrovesical model (UVM) to allow a urologist to practise this critical step. The aim of our study was to compare the effect of task-specific bench model training (anastomotic suturing on the UVM) with that of basic laparoscopic suturing on intracorporeal urethrovesical anastomosis performance.Methods
We recruited 28 senior surgical residents, fellows or staff surgeons for this prospective, single-blinded, randomized controlled study. We randomly assigned participants to an intervention group practising LUA on the UVM or to a control group practising basic laparoscopic suturing and knot-tying on a foam pad. After practising, we videotaped participants performing 5 intra-corporeal interrupted sutures on a foam pad and a LUA on the UVM. A blinded expert scored the videotaped performance using a laparoscopic suturing checklist (CL) and a global rating scale (GRS), and timed the performance.Results
On the foam pad suturing task, the group that trained on the UVM had significantly higher CL scores (10.9 v. 8.1, p = 0.017). On the LUA task, the group that trained on the UVM had significantly higher CL scores (10.9 v. 8.1, p = 0.017), GRS (29.6 v. 22.8, p = 0.005) and shorter times (27.6 v. 38.3 min, p = 0.004) than the control group.Conclusion
Our task-specific bench model was shown to be superior to basic laparoscopic suturing drills on a foam pad. 相似文献25.
We report a case of periprosthetic fracture of the proximal tibia after lateral unicompartmental knee arthroplasty following a trivial fall. At the time of surgery, the components were found to be loose; and there was a large uncontained tibial defect with bone loss and communition at the fracture site. The patient was treated by revision total knee arthroplasty and proximal structural tibial allograft, with a satisfactory result at 5-year follow up. Our case illustrates that a bone-conserving unicompartmental knee arthroplasty, if complicated by a periprosthetic fracture, can also present with a difficult surgical problem. Attention to preoperative planning and to availability of structural allograft for such difficult cases is recommended. 相似文献
26.
A non-randomised retrospective study to compare the results of surgical correction of scoliosis in Duchenne’s muscular dystrophy
(DMD) patients using three different instrumentation systems—Sublaminar instrumentation system (Group A), a hybrid of sublaminar
and pedicle screw systems (Group B) and pedicle screw system alone (Group C). Between 1993 and 2003, 43 patients with DMD
underwent posterior spinal fusion and instrumentation. Group A (n = 19) had sublaminar instrumentation system, Group B (n = 13) had a hybrid construct and Group C (n = 11) was treated with pedicle system. The mean blood loss in Group A was 4.1 l, 3.2 l in Group B and 2.5 l in Group C. Average
operating times in Group A, B and C were 300, 274 and 234 min, respectively. Mean pre-operative, post-operative and final
Cobb angle in Group A was 50.05 ± 15.46°, 15.68 ± 11.23° and 21.57 ± 11.63°, Group B was 17.76 ± 8.50°, 3.61 ± 2.53° and 6.69 ± 4.19°
and Group C was 25.81 ± 9.94°, 5.45 ± 3.88°, 8.90 ± 5.82°, respectively. Flexibility index or the potential correction calculated
from bending radiographs were 60 ± 6.33, 70 ± 4.65 and 67 ± 6.79% for Group A, Group B and Group C respectively. The percentage
correction achieved was 72.5 ± 14.5% in Group A, 82 ± 6% in Group B and 82 ± 8% in Group C. The difference between percentage
correction achieved and the flexibility index was 12.45 ± 8.22, 12.05 ± 1.3 and 15.00 ± 1.21% in Group A, B and C, respectively
The percentage loss of correction in Cobb angles at final follow-up in Group A, B and C was 12.5 ± 3.5, 16.5 ± 1. and 12.5 ± 2.5%,
respectively. Complications seen in Group A were three cases of wound infection and two cases of implant failure; Group B
had a single case of implant failure and Group C had one patient with wound infection and one case with a partial screw pull
out. Early surgery and smaller curve corrections appears to be the current trend in the management of scoliosis in DMD. This
has been possible due to early curve detection and surgery thus having the advantage of less post-operative respiratory complications
and stay in paediatric intensive care. Also, early surgery avoids development of pelvic deformity and extension of instrumentation
to the pelvis thereby reducing blood loss. This trend reflects the advent of newer and safer instrumentation systems, advanced
techniques in anaesthesia and cord monitoring. Sublaminar instrumentation system group had increased operating times and blood
loss compared to both the hybrid and pedicle screw instrumentation systems due to increased bleeding from epidural vessels
and pelvic instrumentation. Overall, the three instrumentation constructs appear to provide and maintain an optimal degree
of correction at medium to long term follow up but the advantages of lesser blood loss and surgical time without the need
for pelvic fixation seem to swing the verdict in favour of the pedicle screw system. 相似文献
27.
Periprosthetic fracture following total knee arthroplasty is a potentially serious complication. This injury can involve the distal femur, proximal tibia or the patella. This review article analyzes the prevalence, risk factors, classification and treatment options for periprosthetic fractures of the femur. 相似文献
28.
Melatonin prevents dexamethasone‐induced testicular oxidative stress and germ cell apoptosis in golden hamster,Mesocricetus auratus 下载免费PDF全文
This study investigated the protective effect of melatonin on dexamethasone (Dex), an extensively used anti‐inflammatory and immunosuppressive synthetic glucocorticoid, induced testicular oxidative stress and germ cell apoptosis in golden hamster. Hamsters were randomly divided into four groups (n = 7): group I – control; group II – melatonin treated (10 mg kg?1 day?1); group III – Dex treated (7 mg kg?1 day?1) and group IV – combination of Dex and melatonin. All the injections were administered intraperitoneally for seven consecutive days. The histopathological changes, specific biochemical markers, including antioxidative enzymes, plasma melatonin level and the markers for germ cell apoptosis were evaluated. Dex administration decreased antioxidant enzyme activities (SOD, CAT, GSH‐PX), plasma melatonin level and melatonin receptor (MT1) expression with a concomitant increase in lipid peroxidation (TBARS) and altered testicular histopathology which might culminate into increased germ cell apoptosis as evident from increased Bax/Bcl‐2 ratio and caspase‐3 expression. However, melatonin pre‐treatment enhanced enzyme activities for SOD, CAT, GSH‐PX with a simultaneous decrease in Bax/Bcl‐2 ratio and caspase‐3 expression. Our findings clearly suggest that melatonin improved defence against Dex‐induced testicular oxidative stress and prevented germ cell apoptosis, suggesting a novel combination therapeutic approach for management of male reproductive health. 相似文献
29.
30.
BACKGROUND CONTEXT: Previous studies have analyzed the outcome following posterior correction and combined anterior-posterior correction for Scheuermann's kyphosis. Traditionally interbody fusion has been obtained using morselized rib graft. Recently the use of titanium anterior cages has been suggested for interbody use. There are no long-term studies comparing these two techniques. PURPOSE: To investigate the potential value of titanium anterior interbody cages compared with morselized rib graft for anterior interbody fusion in combination with posterior instrumentation, correction, and fusion for Scheuermann's kyphosis. STUDY DESIGN: Nonrandomized comparison of two surgical techniques in matched subjects. PATIENT SAMPLE: Fifteen patients with identical preoperative radiographic and physical variables (age, gender, height, weight, body mass index) were managed with combined anterior release, interbody fusion, posterior instrumentation, correction, and fusion. Group A (n=8) had morselized rib graft inserted into each intervertebral disc space. Group B (n=7) had titanium interbody cages packed with bone graft inserted at each level. The posterior instrumentation extended from T2 to L2 in both groups. OUTCOME MEASURES: Preoperative and postoperative curve morphometry was studied on plain radiographs by two independent observers. The indices studied included Cobb angle, Ferguson's angle, Voutsinas index, sagittal vertical axis (SVA), sacral inclination (SI), and lumbar lordosis (LL). Interbody fusion was assessed at final follow-up. Each patient was reviewed at 3, 6, 12, 24, 48, and 60 months after surgery with standing radiographs. METHODS: Both surgical groups were compared in terms of radiological parameters and complications. Wilcoxon-matched pairs test and Mann-Whitney test were used. RESULTS: The average follow-up for Group A was 70 months and for Group B 66 months. For the whole group, the preoperative median Cobb angle for thoracic kyphosis was 86 degrees , the median Ferguson angle was 50 degrees , Voutsinas index was 28.7, SVA -3.5 centimeters, lumbar lordosis was 66 degrees , and the median sacral inclination angle was 40 degrees . The median postoperative Cobb angle was 42 degrees , Ferguson angle 28.4 degrees , Voutsinas index 13, SVA -4.0 centimeters, and the median sacral inclination angle was 34 degrees . There were significant differences between preoperative and postoperative measurements for all variables (p<.01), indicating that good correction was achieved. At 4-year follow-up, fusion criteria were satisfied in 12 of 15 cases (80%). Three patients had distal junctional kyphosis. There was no significant difference obtained in the final Cobb angle, Ferguson angle, and Voutsinas index when Group A (rib graft) was compared with Group B (titanium cage) Both Group A and B patients retained the postoperative correction achieved with respect to all the radiographic parameters studied. CONCLUSION: We were unable to demonstrate any significant advantage for the use of anterior titanium interbody cages over the use of morselized rib graft in the surgical management of Scheuermann's kyphosis. Given the not inconsiderable cost and the need for posterior chevron osteotomies when interbody cages are used, we have now reverted to our previous practice of using morselized rib graft at each intervertebral level. 相似文献