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   14530篇
  免费   449篇
  国内免费   102篇
耳鼻咽喉   96篇
儿科学   288篇
妇产科学   451篇
基础医学   1761篇
口腔科学   357篇
临床医学   1013篇
内科学   4040篇
皮肤病学   222篇
神经病学   1342篇
特种医学   588篇
外科学   2126篇
综合类   35篇
一般理论   1篇
预防医学   509篇
眼科学   156篇
药学   700篇
  1篇
中国医学   24篇
肿瘤学   1371篇
  2024年   67篇
  2023年   108篇
  2022年   206篇
  2021年   428篇
  2020年   222篇
  2019年   317篇
  2018年   398篇
  2017年   290篇
  2016年   330篇
  2015年   373篇
  2014年   559篇
  2013年   712篇
  2012年   980篇
  2011年   1003篇
  2010年   644篇
  2009年   584篇
  2008年   1009篇
  2007年   1012篇
  2006年   921篇
  2005年   960篇
  2004年   861篇
  2003年   791篇
  2002年   710篇
  2001年   85篇
  2000年   74篇
  1999年   107篇
  1998年   150篇
  1997年   109篇
  1996年   131篇
  1995年   87篇
  1994年   100篇
  1993年   79篇
  1992年   71篇
  1991年   60篇
  1990年   51篇
  1989年   42篇
  1988年   32篇
  1987年   25篇
  1986年   40篇
  1985年   32篇
  1984年   30篇
  1983年   25篇
  1982年   33篇
  1981年   33篇
  1980年   32篇
  1979年   21篇
  1977年   9篇
  1976年   10篇
  1974年   9篇
  1964年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The authors analyse the current state of the art of the prosthetic repair of incisional hernia and the problems involved in positioning the prosthesis, comparing their own experience with the most recent literature. From January 1994 to June 2001, 50 patients were operated on for incisional hernia (28 males and 22 females); 12% had recurrent or re-recurrent incisional hernias. Defects smaller than 3 cm were repaired with a polypropylene plug; a double-layer polypropylene mesh placed in a preperitoneal position was used for defects measuring from 3 to 5 cm; in defects greater than 5 cm a double-layer mesh was placed behind the muscle layer. Fifteen patients were operated on under local anaesthesia. Only 22% required postoperative analgesia. The mean hospital stay was 3.95 days. Only 3 recurrences (6%) were recorded. On the basis of our experience it seems appropriate to repair incisional hernias when of small size, preferably under local anaesthesia, avoiding opening the hernia sac, using an extraperitoneal approach with an overlap technique that employs polypropylene.  相似文献   
62.
Background  Roentgenographic and functional outcomes of expandable self locking intramedullary nailing and platelet rich plasma (PRP) gel in the treatment of long bone non-unions are reported. Materials and methods  Twenty-two patients suffering from atrophic diaphyseal long bone non-unions were enrolled in the study. Patients were treated with removal of pre-existing hardware, decortication of non-union fragments, and fixation of pseudoarthrosis with expandable intramedullary nailing (Fixion™, Disc’O Tech, Tel Aviv, Israel). At surgery, PRP was placed in the pseudoarthrosis rim. Results  The thirteen-month follow-up showed 91% (20/22 patients) of patients attaining bony union. The average time to union was 21.5 weeks. No infection, neurovascular complication, rotational malalignment, or limb shortening >4 mm were observed. The healing rate of non-unions was comparable to that observed in previous studies but with a lower complication frequency. Conclusions  The combined use of self locking intramedullary nailing and PRP in the management of atrophic diaphyseal long bone non-unions seems to produce comparable results with less complications than previously reported. Further data are warranted to investigate the single contribution of PRP gel and Fixion nail.  相似文献   
63.
The authors analyse the problems of recurrent varicose veins on the basis of their own experience. The 5-year incidence of recurrent varicose veins ranges from 25 to 40% after internal saphenectomy. The recurrences should be classified in relation to the site and pathogenetic mechanism. The authors assess the effectiveness of a prevention method for sapheno-femoral stump recurrences. The study population consisted of 80 patients undergoing internal saphenectomy. In 34 (Group A) a traditional safenectomy was performed with short stripping, while in 46 (Group B) closure of the ostium with a flap of pectineal fascia was performed in order to prevent recurrences caused by neovascularisation. In Group A the recurrence rate was 27.1% as against 14.8% in Group B. Recurrences originating from the sapheno-femoral stump are mainly caused not only by an inadequate echo-colordoppler preoperative diagnosis and an inadequate or insufficient crossectomy, but also by neovascularisation. The pectineal flap method in our experience is a very simple, effective and complication-free technique to appreciably reduce recurrent varicose veins originating from the sapheno-femoral stump.  相似文献   
64.
65.

Background

Plaque incision and tunical grafting is widely used to correct penile curvatures secondary to Peyronie's disease (PD), but there is no consensus on the ideal graft to be used.

Objective

To evaluate the efficacy, safety, and reproducibility of plaque incision and buccal mucosa grafting (BMG) in the correction of severe penile curvatures secondary to PD.

Design, setting, and participants

Fifteen patients reporting normal erections and stable curvature (>12-mo duration) entered this prospective study carried out at two university hospitals.

Intervention

All patients underwent plaque incision and BMG.

Measurements

Preoperative evaluation included the International Index of Erectile Function (IIEF-5) and penile duplex ultrasounds with measurement of curvature and length of affected side. Follow-up visits were scheduled at 1, 3, 6, and 12 mo postoperatively, then yearly. Three-mo postoperative evaluation included IIEF-5, patient and partner satisfaction, and intracavernous injection test with evaluation of penile rigidity, straightness, and length; patient and partner satisfaction was recorded at all subsequent visits.

Results and limitations

Mean patient age was 56.3 yr and mean penile curvature 72°; five patients had a two-sided curvature with mean second curvature of 37°. There were no complications. All patients resumed unassisted intercourse 1 mo after surgery. Three-mo postoperative evaluation showed 100% penile straightening, 1.8-cm mean increase in length of affected side, no curvature recurrence or de novo erectile dysfunction, 1.6 mean increase in IIEF-5 score, and patient and partner satisfaction of 93.3% and 100%, respectively. Although results remained stable at subsequent follow-up (mean 13.1 mo), a greater number of patients and longer follow-up are needed before drawing any definite conclusions.

Conclusions

BMG provided excellent short-term results, probably because its prompt revascularisation, suggested by the fast return of spontaneous erections, prevented shrinkage, which is the main cause of graft failure. It also proved to be safe and reproducible, thus representing a valuable treatment option for PD.  相似文献   
66.
Background  A new procedure of hemostasis during laparoscopic total mesorectal excision is described. Methods  In our surgical department, from January 2004 to December 2007, 128 patients underwent laparoscopic total mesorectal excision. Among them, 47 patients underwent laparoscopic anterior resection after preoperative radiotherapy, 68 patients underwent laparoscopic anterior resection without preoperative radiotherapy, and 13 patients underwent laparoscopic abdominal perineal amputation. Results  In seven laparoscopic rectal surgery cases, we encountered unstoppable presacral bleeding, not amenable by conventional hemostatic solutions. In these cases we applied a simple staging hemostatic procedure. We first performed local compression: tamponing with a small gauze or absorbable fabric hemostat. If bleeding did not stop, we localized an epiploic or omental scrap and excised it by using bipolar forceps and use it as a plug on the tip of a grasping forceps. This plug is then put on the bleeding source and monopolar coagulation is applied by electrified dissecting forceps through the interposed grasping forceps. If bleeding did not stop, we used a little scrap of bovine pericardium graft and tacked it to the bleeding site using endoscopic helicoidal protack. Conclusions  Our experience suggests that this hemostatic step-by-step procedure is a valid option to control persistent presacral hemorrhages.  相似文献   
67.
The presence of cirrhosis is the only risk factor that is advocated for recurrence of hepatocellular carcinoma (HCC) 2 years after hepatic resection compared with noncirrhotic control subjects; however, data for cohorts of exclusively patients with cirrhosis are lacking. This study was designed to assess risk factors and annual incidence of early (<2 years) and late (>2 years) recurrence after resection of cirrhosis and to compare these findings with those of patients with cirrhosis enrolled in HCC surveillance programs (HCC occurrence). Data from 204 patients with cirrhosis resected for HCC and 150 surveilled for cirrhosis were retrospectively collected and compared using propensity score matching to overcome biases of nonrandomized study. Risk factors for early recurrence (incidence = 21.8%/year) were higher serum alpha-fetoprotein (AFP) levels, poorly differentiated tumor, and presence of microvascular invasion (P < 0.05). Risk factors for both late recurrence (18.4%/year) and HCC occurrence (3.3%/year) were male gender, older age, and higher serum transaminase levels; multiple primary tumors and higher AFP were additional risk factors for late recurrence and HCC occurrence respectively (P < 0.05). After propensity adjustment, resected patients with less than two risk factors for late recurrence showed an annual incidence of HCC (6.2%/year) similar to that of surveilled patients with ≥2 risk factors (5.8%/year; P = 0.898). Early and late recurrence of HCC for patients with cirrhosis after resection have distinct risk factors. Annual incidence of HCC 2 years or more after resection may be similar to that of general patients because the same risk factors are involved; assessment of these characteristics could be useful in tailoring clinical management.  相似文献   
68.
Objectives: Mandibular functional movements lead to complex deformations of bony structures. The aim of this study was to test whether mandibular splinting influences condylar kinematics and temporomandibular joint (TMJ) loading patterns. Materials and methods: Six subjects were analyzed by means of dynamic stereometry during jaw opening–closing with mandibles unconstrained as well as splinted transversally by a cast metal bar fixed bilaterally to two implant pairs in the (pre)molar region. Statistical analysis was performed by means of ANOVAs for repeated measurements (significance level α=0.05). Results: Transversal splinting reduced mandibular deformation during jaw opening–closing as measured between two implants in the (pre)molar region on each side of the mandible significantly by 54%. Furthermore, splinting significantly reduced the distance between lateral condylar poles (average displacement vector magnitude of each pole: 0.84±0.36 mm; average mediolateral displacement component: 45±28% of the magnitude) and led to a medial displacement of their trajectories as well as a mediolateral displacement of stress‐field paths. Conclusions: During jaw opening–closing, splinting of the mandible leads to a significant reduction of mandibular deformation and intercondylar distance and to altered stress‐field paths, resulting in changed loading patterns of the TMJ structures. To cite this article:
Zaugg B, Hämmerle CHF, Palla S, Gallo LM. Implant‐supported mandibular splinting affects temporomandibular joint biomechanics.
Clin. Oral Impl. Res. 23 , 2012; 897–901
doi: 10.1111/j.1600‐0501.2011.02241.x  相似文献   
69.
PURPOSE: In order to characterize the biological effects and molecular mechanism underlying indocyanine-green (ICG)-mediated photo-oxidative cell damage, human cultured retinal pigmented epithelium (RPE) cells preloaded with ICG were exposed to 810-nm laser irradiation. Cell viability and death induction were examined, as well as the modulation of proteins involved in cell death and DNA repair. METHODS: ARPE-19 cells preloaded with 100 microM ICG were irradiated using continuous and micropulsed 810-nm laser for the dye photoactivation, and cell viability and apoptosis were evaluated. The expression and subcellular localization of Bax, Ku70, Ku80 and clusterin/ApoJ were analyzed by immunocytochemistry and Western blot. RESULTS: ICG photoactivation induced apoptosis in RPE cells. The micropulsed laser irradiation induced a higher percentage of cell killing as compared to continuous wave. Cell killing was inhibited by sodium azide, suggesting the involvement of reactive oxygen species in the laser-induced cell damage. Bax was strongly induced after 4 and up to 24 h of treatment. The nuclear proapoptotic isoform of clusterin/ApoJ was selectively upregulated after 24 h of treatment. The DNA repair machinery was upregulated after 4 and up to 24 h. CONCLUSION: These data elucidate some molecular mechanisms involved in cell death induced by ICG photosensitization. The increase and relocalization of Bax into the mitochondria and the upregulation and translocation of the proapoptotic isoform of clusterin/ApoJ in the nucleus demonstrated the involvement of these proteins in the photo-oxidative cell death pathway. These data point out new molecular targets and suggest potential applications in the therapy of the retinal diseases that could benefit by selective RPE treatment.  相似文献   
70.
Summary β-1-galactosyl-0-hydroxylysine (GH) was measured in the urine of 59 women and 48 men, aged 30–79 years, by High Performance Liquid Chromatography (HPLC) of the dansylated derivative. Vertebral mineral density, measured by quantitative computed tomography (QCT), and urinary GH were inversely correlated (r=−0.74;P<0.001). High rate of bone mineral loss is associated with a high urinary GH excretion. Measurement of GH in urine provides a simple and noninvasive method for the evaluation of the extent of bone resorption in large groups of subjects and appears to be more specific than urinary hydroxyproline excretion.  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