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   6764篇
  免费   329篇
  国内免费   94篇
耳鼻咽喉   34篇
儿科学   154篇
妇产科学   123篇
基础医学   746篇
口腔科学   172篇
临床医学   386篇
内科学   1837篇
皮肤病学   197篇
神经病学   604篇
特种医学   344篇
外科学   1227篇
综合类   28篇
一般理论   1篇
预防医学   167篇
眼科学   71篇
药学   366篇
中国医学   9篇
肿瘤学   721篇
  2023年   50篇
  2022年   104篇
  2021年   158篇
  2020年   110篇
  2019年   145篇
  2018年   159篇
  2017年   110篇
  2016年   149篇
  2015年   137篇
  2014年   182篇
  2013年   214篇
  2012年   363篇
  2011年   434篇
  2010年   258篇
  2009年   234篇
  2008年   402篇
  2007年   441篇
  2006年   436篇
  2005年   423篇
  2004年   449篇
  2003年   498篇
  2002年   477篇
  2001年   100篇
  2000年   105篇
  1999年   81篇
  1998年   107篇
  1997年   84篇
  1996年   75篇
  1995年   54篇
  1994年   45篇
  1993年   45篇
  1992年   58篇
  1991年   41篇
  1990年   45篇
  1989年   46篇
  1988年   29篇
  1987年   32篇
  1986年   22篇
  1985年   24篇
  1984年   21篇
  1983年   24篇
  1982年   17篇
  1981年   19篇
  1980年   20篇
  1979年   27篇
  1978年   21篇
  1977年   16篇
  1976年   13篇
  1975年   10篇
  1968年   10篇
排序方式: 共有7187条查询结果,搜索用时 15 毫秒
81.
82.
We developed a hepatic arterialization technique in living donor liver transplantation. The technique was indicated in patients with a left graft from donors with a right hepatic artery originated from superior mesenteric artery or a right graft from donors with a left hepatic artery from left gastric artery. The donor common hepatic and gastroduodenal arteries were split. On the recipient side, left and right hepatic arteries or branches of the right hepatic artery were split, received patch plasty, and anastomosed with the graft arteries under loupe observation. Livers from 25 donors were procured (16 right livers and 9 left livers) using this technique. There were no vascular complications in the donors. Three recipients died due to infectious disease with arterial patency. The remaining 22 recipients survived without hepatic arterial thrombosis. In limited situations, this technique can be adapted for living donor liver transplantation without increasing donor complications.  相似文献   
83.

Objective

This study investigated the relation between self-assessment of upper extremity function and locomotive syndrome in a general population.

Methods

Using the 25-question Geriatric Locomotive Function (GLFS-25) test, 320 Japanese people (115 men, 205 women, mean age 67.6 years, 40–92 years) were evaluated for locomotive dysfunction. All had completed a self-administered questionnaire including items for sex, weight, height, dominant hand, and the degree of frequency of hand in ADL. We measured the bilateral hand grip and key pinch strength as indicators of hand muscle function. Study participants were assessed for upper extremity dysfunction using Hand 10, a self-administered questionnaire for upper extremity disorders, and using the Japanese Society for Surgery of the Hand Version of Disability of the Arm, Shoulder, and Hand. Statistical analyses were conducted to clarify the association between upper extremity dysfunction and screening results for locomotive dysfunction.

Results

Participants reporting any upper extremity dysfunction were 137 (47 men, 90 women) out of 320 participants. The GLFS25 score was found to have significant positive correlation with age and Hand 10 scores. Significant negative correlation was found with the GLFS25 score and dominant grip strength, non-dominant grip strength, dominant key pinch strength, and non-dominant key pinch strength. Univariate analysis revealed a significant association with age, sex, bilateral hand grip, and key pinch, and with the Hand 10 score and Locomotive syndrome. Logistic regression analysis applied after adjustment for age, sex, height, and weight revealed a significant association between Locomotive syndrome and each of non-dominant hand grip (OR 0.73, 95%CI 0.61–0.87) and the Hand 10 questionnaire score (OR 1.10, 95%CI 1.06–1.14).

Conclusion

Locomotive syndrome is associated with the decline of self-assessed and observed upper extremity function.

Study design

Cross-sectional study.  相似文献   
84.
85.
The hepatic arterial buffer response (HABR) is an intrinsic regulatory mechanism of the hepatic artery (HA) that compensates for reductions in portal venous (PV) blood flow. Whether this response is maintained in patients with cirrhosis (LC) is unclear. The aim of the present study was to examine whether HABR is maintained in patients with LC using direct blood flow measurements. PV and HA blood flow were intraoperatively measured and compared in patients with (LC group, n = 39) or without (control group, n = 22) cirrhosis at baseline (baseline HABR) and after PV clamping (acute HABR) using an ultrasound transit-time flowmeter. In contrast to the proportional relationship between the baseline PV and HA blood flow observed in the control group, HA blood flow and the HA-PV flow ratio increased when PV blood flow decreased in the LC group, suggesting that the baseline HABR had already been activated. Acute HABR, evaluated by the absolute and relative changes in HA blood flow and by the buffer capacity, was blunted in the LC group (P < 0.001, P < 0.01, and P = 0.01, respectively). An association between the degree of acute HABR impairment and the level of baseline HABR activation (HA-PV flow ratio) could not be confirmed in the LC group. In conclusion, the baseline HABR appears to be continuously activated in patients with LC; this phenomenon probably results in the impairment of the acute HABR.  相似文献   
86.
87.
BACKGROUND: Despite higher blood loss, morbidity, and mortality, rate of major resection is still high in most surgical institutions because of fear of incomplete tumor removal. To verify whether intraoperative ultrasonography (IOUS) minimizes the rate of major hepatectomies while maintaining treatment radicality, we have prospectively validated our policy, based on extensive use of IOUS resection guidance. STUDY DESIGN: Ninety-three consecutive patients with liver tumors were prospectively enrolled. There were 61 men and 32 women with a mean age of 65.6 years. Fifty-nine patients had hepatocellular carcinoma and 34 had colorectal cancer liver metastases. Surgical strategy was based on the relationship between the tumor and intrahepatic vascular structures at IOUS. Rates of major and minor resection, mortality, morbidity, and rate of local recurrences were evaluated. RESULTS: There was no hospital mortality; major morbidity occurred in 2.2% of patients and minor complications in 17%. Six (6.5%) patients required blood transfusion. Major resections (two or more segments) were accomplished in 14 patients (15%), and 5 (5.4%) patients had more than three segments removed. Major vascular invasion was present in 16 patients (17%), and contact without infiltration with major vessels was present in another 16; part of the wall of the inferior vena cava was resected in 1 patient. Surgical clearance was achieved in all patients without local recurrence at a mean followup of 18 months (median 13, range 6 to 52 months). CONCLUSIONS: This study shows that liver operations performed under IOUS guidance are safe and radical and reduce need for major hepatectomies.  相似文献   
88.
PURPOSE: To evaluate the efficacy of hand-assisted laparoscopic radical nephrectomy (HALRN) in patients with localized stage T(1)/T(2) renal-cell carcinoma, we analyzed the clinical results of our patients treated in this way. PATIENTS AND METHODS: From March 1999 to March 2003, a total of 96 patients aged 28 to 86 years (mean 61 years) with clinical stage T(1)/T(2)N(0)M(0), pathologically confirmed renal-cell carcinoma underwent HALRN. The outcomes were compared with those of open radical nephrectomy, which was performed in 86 patients from November 1991 to February 1999 in our institution. Kaplan-Meier analysis was used to analyze survival. RESULTS: Ten patients (10.4%) had perioperative complications. During a mean follow-up of 25 months (range 6-54 months), no patients died of the cancer, although three patients had metastatic disease. The 4-year disease- free and overall survival rates were 88% and 100%, respectively. Seventy-eight patients who underwent open radical nephrectomy were followed for 38 to 156 months (median 86 months). Seventy-three survived without any recurrent disease, five survived with metastasis, and no patient died of metastatic disease. The 4-year disease-free and overall survival rates were 93% and 100%, respectively. CONCLUSIONS: Hand-assisted laparoscopic surgical management of T(1)/T(2) renal-cell carcinoma is feasible and safe. At our institution, HALRN confers long-term oncologic effectiveness equivalent to that of open radical nephrectomy.  相似文献   
89.
Objectives: To evaluate the correlation between preoperatively predicted and pathologically measured prostate cancer volumes and to investigate the clinical use of preoperatively predicted cancer volume in predicting pathological stage. Methods: Correlations between pathological findings and various preoperative parameters, including the cancer volumes as predicted by using two methods (Vca and estimated PCvol), were analyzed in 196 patients who underwent radical prostatectomy for clinically localized prostate cancer. Results: Pathologically measured prostate cancer volume was significantly correlated with the Vca and estimated PCvol, but the correlation coefficients were respectively only 0.46 and 0.35. Prostate‐specific antigen (PSA), PSA density (PSAD), primary Gleason score, Vca, Vca fraction (Vcafx), and estimated PCvol were significantly higher in 82 patients with extraprostatic cancer than in 114 patients with organ‐confined cancer. Magnetic resonance imaging (MRI) findings were significantly correlated with pathological stage. Multivariate logistic regression analysis indicated that the Vcafx and MRI findings were significant predictors of extraprostatic cancer, but receiver operating characteristic analysis revealed that the combination of Vcafx and MRI findings had no advantage over the combination of Gleason score, PSAD, and MRI findings. Conclusions: Vca and estimated PCvol are significantly correlated with the pathologically measured cancer volume but their ability to accurately predict cancer volume is limited. Vcafx and MRI findings were statistically significant predictors of extraprostatic cancer but their combination was not superior to the combination of Gleason score, PSAD, and MRI findings.  相似文献   
90.
A congenitally narrow cervical spinal canal has been established as an important risk factor for the development of cervical spondylotic myelopathy. However, few reports have described the mechanism underlying this risk. In this study, we investigate the relationship between cervical spinal canal narrowing and pathological changes in the cervical spine using positional magnetic resonance imaging (MRI). Two hundred and ninety-five symptomatic patients underwent cervical MRI in the weight-bearing position with dynamic motion (flexion, neutral, and extension) of the cervical spine. The sagittal cervical spinal canal diameter and cervical segmental angular motion were measured and calculated. Each segment was assessed for the extent of intervertebral disc degeneration and cervical cord compression. Based on the sagittal canal diameter, the subjects were classified into three groups: A, subjects with a congenitally narrow canal, diameter of less than 13 mm; B, subjects with a normal canal, diameter of 13–15 mm; C, subjects with a wide canal, diameter of more than 15 mm. When compared with Groups A and B, the disc degeneration grades at the C3-4, C5-6, and C6-7 segments and the cervical cord compression scores at the C3-4 and C5-6 segments showed significant differences. Additionally, when compare with Groups A and C, the disc degeneration grades at all segments, except C2-3, and the cervical cord compression scores at all segments, except C2-3, showed significant differences. With respect to the cervical kinematics, few differences in the kinematics were observed between Groups B and C, however, the kinematics in Group A was different with other two groups. In Group A, the segmental mobility at the C4-5 and C6-7 segments were significantly higher than those observed in Group B, and the segmental mobility at the C3-4 segment was significantly lower than that observed in Groups B or C. We demonstrated the unique pathological and kinematic traits of cervical spine that exist in a congenitally narrow canal. We hypothesize that kinematic trait associated with a congenitally narrow canal may greatly contribute to pathological changes in the cervical spine. Our results suggest that cervical spinal canal diameter of less than 13 mm may be associated with an increased risk for development of pathological changes in cervical intervertebral discs. Subsequently, the presence of a congenitally narrow canal can expose individuals to a greater risk of developing cervical spinal stenosis.  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