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   4023篇
  免费   166篇
  国内免费   39篇
耳鼻咽喉   13篇
儿科学   67篇
妇产科学   22篇
基础医学   404篇
口腔科学   133篇
临床医学   251篇
内科学   1113篇
皮肤病学   55篇
神经病学   192篇
特种医学   125篇
外科学   833篇
综合类   11篇
预防医学   113篇
眼科学   54篇
药学   356篇
中国医学   26篇
肿瘤学   460篇
  2023年   19篇
  2022年   47篇
  2021年   100篇
  2020年   33篇
  2019年   46篇
  2018年   67篇
  2017年   56篇
  2016年   79篇
  2015年   93篇
  2014年   104篇
  2013年   125篇
  2012年   173篇
  2011年   196篇
  2010年   130篇
  2009年   69篇
  2008年   171篇
  2007年   196篇
  2006年   178篇
  2005年   183篇
  2004年   168篇
  2003年   132篇
  2002年   137篇
  2001年   144篇
  2000年   146篇
  1999年   129篇
  1998年   50篇
  1997年   36篇
  1996年   38篇
  1995年   36篇
  1994年   17篇
  1993年   23篇
  1992年   84篇
  1991年   101篇
  1990年   88篇
  1989年   90篇
  1988年   95篇
  1987年   79篇
  1986年   78篇
  1985年   83篇
  1984年   42篇
  1983年   48篇
  1982年   23篇
  1981年   22篇
  1980年   24篇
  1979年   37篇
  1978年   22篇
  1977年   16篇
  1973年   22篇
  1970年   18篇
  1969年   25篇
排序方式: 共有4228条查询结果,搜索用时 31 毫秒
131.

Background

There are numerous reports and evidences to suggest that exercise therapy is effective for knee osteoarthritis (knee OA). However, there is a lack of sufficient research concerning the factors influencing its application and effectiveness. The purposes of this study were to evaluate effects of the mode of treatment delivery on the improvement of symptoms in knee OA, and to analyze potential risk factors affecting improvement after exercise therapies.

Methods

The 209 women applicants diagnosed with knee OA were randomly allocated into either a group performing group exercise in a class or a group performing home exercise. The 90 min exercise program was performed under the guidance of physiotherapists as a group exercise therapy. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) of the subjects of both groups before and after intervention was compared to examine the effect of exercise therapy. In addition, body mass index, knee range of motion (ROM), the femorotibial angle from radiographs, OA severity from Kellgren–Lawrence grade, and meniscus abnormality and subchondral bone marrow lesions from MRI findings were statistically analyzed as factors that may affect exercise therapy.

Results

A significantly greater improvement in WOMAC was observed in the subjects of group exercise (81 subjects) as compared with the subjects of home exercise (122 subjects). There was a significantly high proportion of subjects with knee flexion contracture among the subjects participating in group exercise that showed only minor symptom improvement (p < 0.05). In addition, exercise therapy proved to be highly effective for subjects with limited quadriceps muscle strength (p < 0.05).

Conclusions

When prescribing exercise therapy for knee OA, evaluation of a subject’s ROM and muscle strength is important in deciding whether to commence exercise therapy and what type of exercise therapy to apply; it is also important in predicting the effect of exercise therapy.  相似文献   
132.
As the numbers of aging patients with manifestations of renal disease increase, the elderly must frequently undergo renal biopsies. This study examined the characteristics of clinicopathological correlations in elderly patients. Medical and clinical records from renal biopsies registered in two hospitals between January 2000 and December 2004 were reviewed. Among 406 patients (female: male 224/182; age 43.9 ± 18.8 years, mean ± SD) who underwent renal biopsies, 61 (15.1%) who were aged 65 years and older (female: male, 29/32; age 72.8 ± 5.2 years) were selected. The elderly usually underwent percutaneous renal biopsies for renal diseases such as nephrotic syndrome (43%) and acute or rapidly progressive renal failure (A/RPRF, 39%). Focal/segmental glomerulosclerosis (23%), minimal change disease (19%), and membranous nephropathy (15%) are frequently diagnosed based on biopsy specimens from patients with nephrotic syndrome. Among patients presenting with A/RPRF, 17 (71%) and 4 (17%) had pauci-immune, MPO-ANCA positive, crescentic glomerulonephritis and interstitial nephritis, respectively, and benefited from therapeutic intervention. Histopathological and pre-biopsy clinical diagnoses differed in nine (15%) patients. The complication rate after biopsy was low (3%). Primary glomerular diseases presenting with nephrotic syndrome and primary crescentic glomerulonephritis associated with rapidly progressive renal failure were the most frequently diagnosed among the elderly who underwent renal biopsy. Percutaneous renal biopsy provides clinically useful information about the elderly because clinical presentation and the predicted diagnosis sometimes vary.  相似文献   
133.

Purpose

The reduction of periosteal compression through the use of a locking plate may minimize disturbances of bone blood supply and may improve the rate of bone union. A single-centre, assessor blinded randomized controlled trial was conducted to compare the clinical effectiveness of a locking plate and a non-locking plate.

Methods

A total of 52 patients with AO/OTA 44B lateral malleolar fractures were included in this study. All patients underwent surgical fixation using a lag screw and neutralization plate. An identical treatment protocol was used in all patients, with exception of plate selection. The rate of radiographic bone union, defined as the complete disappearance of fracture lines confirmed through anteroposterior, lateral, and internal oblique views was compared at three, six, and 12 months following surgery. In addition, the Medical Outcomes 36-Item Short-Form Health Survey (SF-36) score, the time required for resolution of tenderness at the fracture site and the complication rate were evaluated.

Results

Twenty-three patients were randomly assigned to undergo fixation using a locking plate, and 29 patients were assigned to undergo fixation using a non-locking plate. Intention-to-treat analysis showed no difference in the radiographic bone union rate of fibula, SF-36 score, the time for resolution of tenderness at the fracture site and complication rates.

Conclusion

No differences were observed in patients with AO/OTA 44B lateral malleolar fractures undergoing fixation with a locking versus non-locking neutralization plate.  相似文献   
134.
Minimally invasive surgery to the posterolateral craniovertebral junction (CVJ) has not been sufficiently described. The aims of this study were to evaluate the feasibility of an endoscopic far-lateral approach to the posterolateral craniocervical junction and to better understand the related anatomy under distorted endoscopic view. Ten fresh cadavers were studied with 4-mm 0° and 30° endoscopes to develop the surgical approach and to identify surgical landmarks. After making a 3-cm straight incision behind the mastoid process, the superior oblique and rectus capitis posterior major muscles were partially exposed. An endoscope was then introduced and the two muscles were followed inferiorly until the posterior arch of the atlas appeared. The two muscles were removed to create ample working space without violating the posterior atlanto-occipital membrane. The vertebral artery was identified by the landmark of the posterior arch of the atlas, and the atlanto-occipital joint and foramen magnum were exposed. In addition to suboccipital craniectomy, transcondylar, supracondylar, and paracondylar extension by drilling were applicable through the narrow corridor under superb visualization. The intradural neurovascular structures from the acousticofacial bundle to the dorsal root of C2, anterolateral space of the foramen magnum, cerebellomedullary fissure, and fourth ventricle were clearly demonstrated. This endoscopic far-lateral approach offers excellent exposure of surgical landmarks around the posterolateral CVJ with minimal invasiveness. Endoscopic soft tissue dissection is key to creating the surgical corridor. This approach could offer an alternative to the conventional far-lateral approach in selected cases.  相似文献   
135.

Background

This study was designed to determine the surgical outcomes of gastric cancer in elderly patients. This information can help establish appropriate treatment for these patients.

Methods

A total of 1,193 patients with gastric cancer who underwent gastrectomy between 1995 and 2010 were enrolled in this retrospective study. The clinicopathologic features of 104 elderly patients (aged ≥80 years) were compared with those of 1,089 nonelderly patients.

Results

(1) Tumors located in the lower-third of the stomach, differentiated cancer, and surgery with limited lymph node dissection were more common in elderly patients. However, there was no difference in the proportion of laparoscopic gastrectomy between elderly and nonelderly patients. (2) Although surgical complication rates were similar in the two groups, the operative mortality rate was higher in elderly patients (1.9 %) than in nonelderly patients (0.7 %). (3) Elderly patients had a significantly poorer overall survival rate, whereas the disease-specific survival rates of the two groups were similar. Limited lymph node dissection did not influence the disease-specific survival rate of elderly patients. (4) The median life expectancy of elderly gastric cancer survivors was 9.8 years in patients aged 80–84 years and 6.0 years in those ≥85 years. The patients with limited lymph node dissection had slightly better prognosis.

Conclusions

The treatment results in elderly patients were comparable to those in nonelderly patients. These findings suggest that R0 resection with at least limited lymph node dissection according to Japanese guidelines should be considered, even for elderly patients.  相似文献   
136.
Background: Methylation status of the cytokine genes may play a role in the pathogenesis of inflammatory diseases, such as rheumatoid arthritis (RA) and chronic periodontitis (CP). This study was undertaken to evaluate whether the DNA methylation profile of the interleukin‐6 (IL‐6) gene promoter was unique to individuals with RA and CP. Methods: The study participants consisted of 30 patients with RA, 30 patients with CP, and 30 age‐, sex‐, and smoking status–balanced healthy controls. Genomic DNA isolated from peripheral blood was modified by sodium bisulfite and analyzed for DNA methylation levels of IL‐6 gene with direct sequencing. Levels of IL‐6 were determined by an enzyme‐linked immunosorbent assay. Results: The region of IL‐6 gene promoter from ?1200 to +27 bp was shown to contain 19 CpG motifs. The methylation levels of the CpG motif at ?74 bp were significantly lower in patients with RA and CP than those in controls (P = 0.0001). Both levels of serum IL‐6 and IL‐6 production by mononuclear cells were significantly different between individuals with and without the methylation at ?74 bp (P = 0.03). The +19 bp motif exhibited differential levels of the methylation among the groups, which was not associated with serum levels of IL‐6. The other 17 CpG motifs exhibited comparable levels of the methylation between the groups. Conclusion: These results suggest that hypomethylated status of a single CpG in the IL‐6 promoter region may lead to increased levels of serum IL‐6, implicating a role in the pathogenesis of RA and CP.  相似文献   
137.
This article presents the case of a Japanese woman who had Ekman-Westborg-Julin trait. She had general macrodontia with multituberculism, evagination of the premolar, single conical roots, shovel-shaped incisors, enamel hypoplasia, impacted tooth, dental crowding, and an open bite. The oral and general characteristics of this patient are described and include the histological and radiographic findings of the mandibular third molars. We suggest that the distinctive oral features with macrodontia of the permanent teeth, multituberculism, evagination, single conical roots, and impaction of the tooth could be defined as the Ekman-Westborg-Julin trait.  相似文献   
138.
139.

Background

The concept of laparoscopic subtotal cholecystectomy (LSC), without approaching Calot’s triangle to avoid both laparotomy and serious complications, is not widely accepted. In this study, we evaluated the outcomes of LSC for severe cholecystitis when dissection of the cystic duct and cystic artery is hazardous.

Methods

From January 2004 to December 2013, 110 consecutive patients who underwent LSC without ligation of the cystic duct and vessels were enrolled in this retrospective study. Their clinical records, including operative records and outcomes, had been entered into a prospectively maintained database and were analyzed.

Results

The mean operating time and blood loss were 121 min and 33.8 ml, respectively. All LSCs were completed without conversion to an open procedure. No injuries to the bile duct or vessels were experienced. Postoperative complications occurred in ten (9.1 %) patients, including subhepatic hematoma in 3, bile leakage in 3, and subhepatic abscess in 1. Patients recovered from complications without requiring re-operation. During follow-up periods (mean 30.7 months), symptomatic biliary stone diseases relapsed in three patients (2.7 %) and were successfully treated by endoscopic management.

Conclusions

LSC without an attempt to dissect Calot’s triangle is a safe and feasible procedure that can avoid conversion to laparotomy.
  相似文献   
140.
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