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   5319篇
  免费   241篇
  国内免费   8篇
耳鼻咽喉   79篇
儿科学   164篇
妇产科学   52篇
基础医学   516篇
口腔科学   71篇
临床医学   469篇
内科学   1185篇
皮肤病学   79篇
神经病学   394篇
特种医学   246篇
外科学   914篇
综合类   80篇
一般理论   4篇
预防医学   217篇
眼科学   208篇
药学   408篇
  3篇
中国医学   19篇
肿瘤学   460篇
  2024年   27篇
  2023年   52篇
  2022年   105篇
  2021年   204篇
  2020年   116篇
  2019年   169篇
  2018年   183篇
  2017年   138篇
  2016年   172篇
  2015年   158篇
  2014年   241篇
  2013年   281篇
  2012年   445篇
  2011年   502篇
  2010年   240篇
  2009年   235篇
  2008年   311篇
  2007年   353篇
  2006年   294篇
  2005年   257篇
  2004年   247篇
  2003年   258篇
  2002年   191篇
  2001年   55篇
  2000年   38篇
  1999年   39篇
  1998年   40篇
  1997年   28篇
  1996年   18篇
  1995年   16篇
  1994年   15篇
  1993年   13篇
  1992年   18篇
  1991年   16篇
  1990年   17篇
  1989年   18篇
  1988年   2篇
  1987年   11篇
  1986年   8篇
  1985年   2篇
  1984年   4篇
  1982年   2篇
  1981年   2篇
  1980年   3篇
  1979年   3篇
  1978年   2篇
  1977年   5篇
  1976年   2篇
  1975年   3篇
  1969年   3篇
排序方式: 共有5568条查询结果,搜索用时 15 毫秒
991.
BACKGROUND: Large colonic polyps or polyps that lie in anatomical locations that are difficult to access at endoscopy may not be suitable for endoscopic resection and therefore may require partial colectomy. This approach eradicates the polyp and allows an oncologic resection should the polyp prove to be malignant. The purpose of this study was to assess outcomes of a laparoscopic approach for the management of these polyps. METHODS: Patients referred for laparoscopic colectomy for colonic polyps were identified from the prospective colorectal laparoscopic surgery database. Demographics, operative details, and final pathology were reviewed. RESULTS: Fifty-one consecutive patients (27 male) with a mean age of 68 +/- 11.4 years, ASA classification (1/2/3/4) of 0/21/27/3, and body mass index (BMI) of 26.5 +/- 4.9 were identified. Right (RHC) and left (LHC) colectomy was performed for 39 right and 12 left colonic polyps. Mean operating time (OT) was 87 +/- 30 min (81 for RHC, 105 for LHC) and mean hospital stay was 3.1 +/- 1.9 days. There were six complications (17.7%), including anastomotic leak (n = 1), small bowel obstruction (n = 2), abscess (n = 1), and exacerbation of preexisting medical conditions (n = 2). Four patients were readmitted (7.8%); one required CT scan-guided abscess drainage (1.9%) and two required reoperation (3.9%). Five patients (9.8%) were converted because of adhesions (n = 3), obesity (n = 1), and inability to identify the area that was tattooed at colonoscopy (n = 1). Mean polyp size was 3.1 cm, and pathology revealed tubular (n = 14), tubulovillous (n = 33) and villous adenoma (n = 2), pseudopolyp (n = 1), and prolapse of the appendix into the cecum mimicking an adenoma (n = 1). High-grade dysplasia was seen in four tubular (33%) and five tubulovillous adenomas (15.5%). Adenocarcinoma not identified at colonoscopy was found in 11 polyps (20%), 9 tubulovillous (27.8%) and both villous adenomas (100%). CONCLUSIONS: Large colonic polyps unresectable at colonoscopy are associated with a high rate of unsuspected cancer. This requires a formal colectomy rather than transcolonic polypectomy. Laparoscopic colectomy offers safe and effective management of these polyps with the benefits of accelerated postoperative recovery.  相似文献   
992.
BACKGROUND: Movement processes for 2 different suturing techniques within a single surgical task were quantified. METHODS: Junior (postgraduate years 1-2) and senior residents (postgraduate year 3 and higher) were tested on their ability to perform a vascular anastomosis on a live porcine model 1 week after a guided practice session. Two phases of 2 suturing techniques (parachute and running) were identified, and performance was evaluated during each phase using computer hand motion analysis (CHMA) and expert-based measures. RESULTS: Senior residents were more efficient on all segments based on CHMA and expert-based ratings (P < .05). CHMA showed a significant improvement in junior resident performance during each phase of the procedure (warm-up effect). The change in task difficulty during transition from parachute to running sutures was identifiable using CHMA. CONCLUSIONS: Different suturing techniques are executed using the same general motor program although specific program parameters are adjusted to suit each technique. The findings support a novel form of construct validity the for surgical assessment device, the concept of transfer of skills, and the use of computer evaluations for the assessment of technical skills embedded within complex surgical tasks.  相似文献   
993.
994.
World Journal of Surgery - The Global Initiative for Children's Surgery (GICS) group produced the Optimal Resources for Children’s Surgery (OReCS) document in 2019, listing standards of...  相似文献   
995.
996.

Purpose

Humans differ from other great ape species in their propensity to develop tears of the rotator cuff. The aim of this study was to compare the anatomical risk factors for subacromial impingement and rotator cuff tears amongst the great apes and to determine which features may be accentuated in humans and therefore play a more significant role in disease aetiology.

Methods

Orthogonal digital photographs of 22 human, 17 gorilla, 13 chimpanzee and 12 orangutan dry bone scapula specimens oriented in the glenoid plane were taken. Anatomical measurements were preformed using a calibrated digital image technique and the results scaled according to scapula vertebral border length.

Results

Of the ten anatomical features associated with subacromial impingement and rotator cuff tears in humans, none were shown to be accentuated and significantly different to the other species studied. However the human supraspinatus fossa was shown to be significantly smaller.

Conclusions

These results indicate that an alternative primary aetiological factor for rotator cuff tears must exist. A reduction in the size of the supraspinatus fossa in human scapulae suggests that structural insufficiency of the supraspinatus or a change in rotator cuff force vectors could play a role.  相似文献   
997.

Purpose

We sought to determine the impact of esophagectomy on survival in patients with adenocarcinoma of the esophagus cancer after chemoradiotherapy (CRT).

Methods

A database of esophageal cancer was queried for nonmetastatic patients with adenocarcinoma treated between 2000 and 2011 with CRT. Overall survival (OS) and recurrence-free survival (RFS) curves were calculated according to the Kaplan–Meier method and log-rank analysis. Multivariate analysis was performed by the Cox proportional hazard model.

Results

We identified 154 patients (60 without surgery; 94 with surgery) who were included in the analysis. The only differences between the 2 groups were more advanced disease stage, improved performance status, and younger age in the surgery group. Patients undergoing surgery had significantly higher survival. Median and 5-year OS for surgical patients were 4.1 years and 43.6 %, versus 1.9 years and 35.6 % for nonsurgical patients (p = 0.007). Multivariate analysis for OS and RFS revealed that factors associated with increased survival were surgical resection, tumor length < 5 cm, male gender, and lower stage. Age, tumor location, radiation dose/technique, and induction chemotherapy were not prognostic. There was a trend toward improved survival on univariate analysis (p = 0.10) and multivariate analysis (p = 0.063) for surgical patients compared to nonsurgical patients who were healthy enough for surgery before CRT (n = 38), and no difference in OS in nonsurgical patients healthy enough for surgery after CRT (n = 22).

Conclusion

Esophagectomy after CRT is associated with improved survival in patients with adenocarcinoma after CRT. Trimodal therapy should continue to remain the standard of care for esophageal adenocarcinoma.  相似文献   
998.
999.
1000.
ObjectiveTo examine the burden of mental health issues (MHI), namely anxiety, depressive disorders, and suicide, in a population-based cohort of older men with localized prostate cancer and to evaluate associations with primary treatment modality.Patients and methodsA total of 50,856 men, who were 65 years of age or older with clinically localized prostate cancer diagnosed between 1992 and 2005 and without a diagnosis of mental illness at baseline, were abstracted from the Surveillance, Epidemiology, and End Results–Medicare database. The primary outcome of interest was the development of MHI (anxiety, major depressive disorder, depressive disorder not elsewhere classified, neurotic depression, adjustment disorder with depressed mood, and suicide) after the diagnosis of prostate cancer.ResultsA total of 10,389 men (20.4%) developed MHI during the study period. Independent risk factors for MHI included age≥75 years (hazard ratio [HR] = 1.29); higher comorbidity (Charlson comorbidity index≥3, HR = 1.63); rural hospital location (HR = 1.14); being single, divorced, or widowed (HR = 1.12); later year of diagnosis (HR = 1.05); and urinary incontinence (HR = 1.47). Black race (HR = 0.79), very high-income status (HR = 0.87), and definitive treatment (radical prostatectomy [RP], HR = 0.79; radiotherapy [RT], HR= 0.85, all P<0.001) predicted a lower risk of MHI. The rates of MHI at 10 years were 29.7%, 29.0%, and 22.6% in men undergoing watchful waiting (WW), RT, and RP, respectively.ConclusionOlder men with localized prostate cancer had a significant burden of MHI. Men treated with RP or RT were at a lower risk of developing MHI, compared with those undergoing WW, with median time to development of MHI being significantly greater in those undergoing RP compared with those undergoing RT or WW.  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