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   6476篇
  免费   338篇
  国内免费   23篇
耳鼻咽喉   58篇
儿科学   335篇
妇产科学   67篇
基础医学   564篇
口腔科学   297篇
临床医学   510篇
内科学   1389篇
皮肤病学   184篇
神经病学   480篇
特种医学   251篇
外科学   1048篇
综合类   107篇
一般理论   2篇
预防医学   253篇
眼科学   299篇
药学   449篇
中国医学   30篇
肿瘤学   514篇
  2024年   7篇
  2023年   76篇
  2022年   179篇
  2021年   319篇
  2020年   159篇
  2019年   243篇
  2018年   277篇
  2017年   222篇
  2016年   236篇
  2015年   266篇
  2014年   381篇
  2013年   444篇
  2012年   632篇
  2011年   622篇
  2010年   323篇
  2009年   261篇
  2008年   379篇
  2007年   346篇
  2006年   264篇
  2005年   293篇
  2004年   246篇
  2003年   186篇
  2002年   172篇
  2001年   23篇
  2000年   14篇
  1999年   33篇
  1998年   32篇
  1997年   22篇
  1996年   17篇
  1995年   13篇
  1994年   14篇
  1993年   13篇
  1992年   9篇
  1991年   10篇
  1990年   6篇
  1989年   6篇
  1988年   5篇
  1987年   7篇
  1986年   5篇
  1985年   5篇
  1984年   5篇
  1982年   8篇
  1981年   6篇
  1980年   7篇
  1979年   5篇
  1978年   9篇
  1977年   4篇
  1976年   5篇
  1975年   3篇
  1970年   3篇
排序方式: 共有6837条查询结果,搜索用时 0 毫秒
41.
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   
42.

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   
43.
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   
44.
The study consisted of application of anti-ubiquitin antibodies (Abs)-coated iron oxide-nanoparticles (IONPs) for minimisation of oxidative stress to contemporary live spermatozoa from the raw semen. Round-shaped IONPs (12.09 ± 0.91 nm) after two-stage functionalisation (silanisation and pegylation) were conjugated with Abs. Four aliquots from each of the 24 ejaculates (4 buffalo bulls) formed Control (Group I) and treatment (II, III and IV) groups; each containing 150 ± 25 million dead/damaged spermatozoa. IONPs-Abs complex were added at ratio of 1:1 (0.5 µg/ml), 1:2 (1.0 µg/ml) and 1:4 (2.0 µg/ml), respectively, in Groups II, III and IV. The semen quality parameters showed improvement at lag-stage (post-nano-purification before processing for cryopreservation). The mean post-thaw motility (%) in Group IV was found to be greater (p < .05) than Group I. Moreover, the overall DNA integrity (%) at post-thaw stage was improved in the nano-purified semen samples. The value of malondialdehyde was greater (p < .001) in Group I than Groups II, III and IV. The mean total antioxidant capacity and superoxide dismutase (U/mg protein) activity values in Group IV was greater (p < .05) than Group I. The study results show that IONPs conjugated with anti-ubiquitin Abs at 2.0 µg/ml can be an effective dose for depletion of dead/damaged spermatozoa from buffalo ejaculates to minimise oxidative stress.  相似文献   
45.
Transmigration of an impacted tooth through the symphyseal suture is a rare and special developmental anomaly of unknown etiology that is unique to the mandibular canine. Maxillary canine transmigration is even rarer. Transmigrated canines are particularly significant due to the aesthetic and functional importance. A maxillary lateral incisor crossing the mid-palatal suture has never been reported in the literature. The aim of this report is to present the first case of simultaneous transmigration of a lateral incisor and canine in the maxilla. The paper also reports four unusual cases of unilateral canine transmigration in the maxilla and mandible and successful eruption of one of the transmigrated mandibular canines following orthodontic traction. Etiology of transmigration and its clinical considerations are also discussed.  相似文献   
46.
Dapsone hypersensitivity syndrome: a clinico-epidemiological review   总被引:4,自引:0,他引:4  
Diaminodiphenyl sulphone (dapsone) is a drug of choice in the treatment of leprosy. It is also useful for the treatment of many neutrophilic and other dermatoses. Dapsone hypersensitivity syndrome is a rare but well recognized serious adverse effect characterized by fever, skin rashes, generalized lymphadenopathy, hepatitis, and hepato-splenomegaly. Twenty-six patients with dapsone hypersensitivity syndrome were studied for clinical profile, outcome, and prognosis. The male:female ratio was 2.2:1, and the mean age was 33.19 years (range 13 to 64 years). The interval between start of dapsone therapy and appearance of symptoms varied from 2-7 weeks (mean 29.82 days). Twenty-four patients received dapsone as a part of multi-drug therapy for leprosy; the other two patients received dapsone for lichen planus and acne vulgaris. Exfoliative dermatitis was the most common cutaneous manifestation followed by erythematous maculo-papular eruption and Stevens-Johnson syndrome-like lesion. The other common systemic manifestations were: fever (26 cases), itching (22 cases), lymphadenopathy (21 cases), jaundice (21 cases), pallor (20 cases), hepatomegaly (19 cases), and pedal edema (14 cases). Investigation profile revealed elevated levels of serum liver enzymes in 100% of patients, elevated erythrocyte sedimentation rate in 92.3%, raised bilirubin in 84.6%, leucocytosis in 69.23%, low hemoglobin (<9 gm/dl) in 46.15% and hypoproteinemia in 42.3%. Eosinophilia, hemolytic anemia, and reticulocytosis count were found in 4 patients each. All the patients had favorable outcomes except three who died due to hepatic failure. Medical personnel must be aware of this potentially fatal syndrome, because it can cause considerable morbidity and mortality.  相似文献   
47.
PURPOSE: To evaluate recovery of the corneal subbasal nerve plexus and corneal sensitivity after myopic laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratectomy (LASEK). SETTING: Manchester Centre for Vision, Royal Eye Hospital, Manchester, United Kingdom. METHODS: Thirty LASEK patients and 20 LASIK patients had slit-scanning confocal microscopy and noncontact corneal esthesiometry preoperatively and 1, 3, and 6 months after surgery. Images of the subbasal nerve plexus were analyzed using customized software to evaluate nerve regeneration. RESULTS: Central corneal sensitivity decreased significantly 1 month after LASEK and LASIK and returned to normal levels after 3 months. Corneal subbasal nerve fiber density, nerve branch density, nerve fiber length, and nerve fiber width decreased significantly 1 month after LASIK and had not returned to the preoperative levels by 6 months. Nerve fiber tortuosity decreased significantly 1 month after LASEK and returned to the preoperative levels 3 months after surgery. There were no significant differences in nerve fiber tortuosity before and after LASIK. Neither corneal sensitivity nor nerve fiber morphology was different between the 2 groups at any postoperative visit. CONCLUSIONS: Corneal sensitivity and subbasal nerve morphology were adversely affected by LASEK and LASIK. Corneal sensitivity recovered 3 months after the procedure, but subbasal nerves were still abnormal after 6 months. Despite the different forms of surgical trauma to corneal nerves with LASIK and LASEK, there was no apparent difference in the time course of recovery of corneal structure and function.  相似文献   
48.
49.
50.
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