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   6677篇
  免费   272篇
  国内免费   12篇
耳鼻咽喉   105篇
儿科学   207篇
妇产科学   64篇
基础医学   641篇
口腔科学   96篇
临床医学   557篇
内科学   1479篇
皮肤病学   92篇
神经病学   497篇
特种医学   309篇
外科学   1153篇
综合类   98篇
一般理论   4篇
预防医学   266篇
眼科学   270篇
药学   525篇
  3篇
中国医学   24篇
肿瘤学   571篇
  2024年   31篇
  2023年   63篇
  2022年   128篇
  2021年   252篇
  2020年   137篇
  2019年   222篇
  2018年   228篇
  2017年   177篇
  2016年   203篇
  2015年   188篇
  2014年   314篇
  2013年   368篇
  2012年   550篇
  2011年   609篇
  2010年   315篇
  2009年   291篇
  2008年   399篇
  2007年   434篇
  2006年   373篇
  2005年   342篇
  2004年   301篇
  2003年   325篇
  2002年   227篇
  2001年   67篇
  2000年   44篇
  1999年   48篇
  1998年   46篇
  1997年   35篇
  1996年   24篇
  1995年   24篇
  1994年   22篇
  1993年   16篇
  1992年   24篇
  1991年   19篇
  1990年   21篇
  1989年   21篇
  1988年   3篇
  1987年   12篇
  1986年   8篇
  1985年   3篇
  1984年   5篇
  1981年   3篇
  1980年   3篇
  1979年   3篇
  1978年   3篇
  1977年   5篇
  1976年   4篇
  1975年   3篇
  1970年   3篇
  1969年   4篇
排序方式: 共有6961条查询结果,搜索用时 15 毫秒
31.
Patients with Fabry disease on dialysis in the United States.   总被引:9,自引:0,他引:9  
BACKGROUND.: Fabry disease results from an X-linked deficiency of lysosomal alpha-galactosidase A and is a rare cause of end-stage renal disease. Little is known about the characteristics of patients with Fabry disease that initiate dialysis in the United States, although data from Europe suggests these individuals have a poor survival. METHODS.: Using the United States Renal Disease System database, we first studied in detail 42 Fabry patients who initiated dialysis between April 1995 (following the introduction of the new detailed HCFA 2728 form) and July 1998. To examine crude survival in a larger cohort, 95 Fabry patients were studied who initiated dialysis between 1985 and 1993, similar to the European Registry. Diabetic and non-diabetic controls matched by age, gender, race, year of dialysis initiation, and initial dialysis modality were examined for comparison. RESULTS.: During the years 1995 to 1998, the mean age of Fabry patients that initiated dialysis was 42 years, 83% were Caucasian, and 10% were African American. Despite the X-linked inheritance of Fabry disease, 12% of Fabry patients on dialysis were female. At initiation of dialysis mean serum albumin and creatinine were significantly higher and mean body mass index was significantly lower among Fabry patients, but mean glomerular filtration rate was similar to controls. Fabry patients tended to have a lower three-year survival compared to non-diabetic controls, but the results were not significantly different. In a larger cohort of Fabry patients who initiated dialysis between 1985 and 1993, the three-year survival of Fabry patients was significantly lower than non-diabetic controls: 63% (95% CI, 50 to 75%) versus 74% (95% CI, 67 to 80%; P=0.03). CONCLUSION.: End-stage renal disease is associated with significant morbidity and mortality among patients with Fabry disease. Recent evidence that progression of Fabry disease may be attenuated by enzyme replacement therapy necessitates increased awareness of Fabry disease and its comorbidities.  相似文献   
32.
Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? The indications and timing of native nephrectomy in patients with autosomal dominant polycystic kidney disease (ADPKD) is controversial, especially for those undergoing renal transplantation. Post‐transplant unilateral native nephrectomy appears to be the preferred intervention compared to pre‐transplant native nephrectomy. There seems to be substantial additive risk to bilateral over unilateral nephrectomy, especially prior to transplantation. Pre‐transplant native nephrectomy should only be carried out when there are clear indications such as massive size preventing allograft placement, severe pain, early satiety, recurrent bleeding and infections, or suspected malignancy.

OBJECTIVE

To analyse indications, timing and outcomes of native nephrectomy in autosomal dominant polycystic kidney disease (ADPKD) patients listed for kidney transplantation.

PATIENTS AND METHODS

A retrospective analysis of all ADPKD patients who had a native nephrectomy prior to or following transplantation between January 2003 and December 2009 at a single centre, including those undergoing the sandwich technique (removal of the most severely affected native kidney prior to transplantation, and the other afterwards), was undertaken.

RESULTS

There were 35 individuals in our cohort (M : F = 16 : 19), with a median age of 51.5 years (range 43–65). Twenty patients were in the pre‐transplant nephrectomy group, 12 in the post‐transplant group, and three underwent the sandwich technique. Indications for nephrectomy varied but were most commonly pain/discomfort, space for transplantation, ongoing haematuria, recurrent infections, and gastrointestinal pressure symptoms (early satiety). Seven individuals in the pre‐transplant group and three in the post‐transplant group required critical care admission after nephrectomy. Transient renal graft dysfunction occurred in two post‐transplant bilateral nephrectomy patients. Two patients in the bilateral nephrectomy pre‐transplant group and one in the bilateral nephrectomy post‐transplant group died in the immediate post‐operative period. No complications were noted in the sandwich technique group.

CONCLUSION

Native nephrectomy in ADPKD is a major undertaking associated with significant morbidity especially in the pre‐transplant group. Post‐transplant unilateral nephrectomy appears to be the safest approach with fewest complications.  相似文献   
33.
BACKGROUND: The purpose of this study was to develop a prognostic system applicable to patients with hepatic metastasis from colorectal cancer in whom extrahepatic disease was excluded by preoperative PET with [(18)F]fluoro-2-deoxy-D-glucose (FDG-PET). Data from two institutions were analyzed separately and together to improve general applicability of results. STUDY DESIGN: Data were analyzed for 285 consecutive patients undergoing liver resection for colorectal metastases from 1995 to 2005 at 2 institutions routinely using preoperative FDG-PET with. Fifteen clinicopathologic variables of the primary and secondary tumors were examined to identify factors predictive of survival. RESULTS: Outcomes were correlated with poorly differentiated tumor grade in both data sets. Because patients with poorly differentiated tumors comprised a small proportion (16%) of the population, patients with well-differentiated or moderately differentiated tumors were analyzed independently. In this subgroup, positive lymph node status in the primary colorectal tumor resection specimen was the only characteristic that predicted survival of patients in both institutions. Consequently, patients were sorted into three prognostic categories: poor tumor differentiation; well-differentiated or moderately differentiated tumors and node positive; and well-differentiated or moderately differentiated tumors and node negative. These groups had significantly different overall survival on Kaplan-Meier analysis (p=0.0014). CONCLUSIONS: In patients with colorectal liver metastases staged with FDG-PET with overall survival can be predicted directly from data in the pathology report of the colorectal primary tumor. This study also indicates the need for new molecular tumor markers of prognosis to complement clinicopathologic markers if the goal of prediction of outcomes in individual patients is to be reached.  相似文献   
34.
Background Laparoscopic fundoplication represents the gold standard in the surgical management of gastro-esophageal reflux disease (GERD). The achievement of long-lasting symptomatic and physiological control of reflux is the goal of therapy, as well as the minimization of troubling sequelae, in particular, dysphagia. On-table endoscopy after fundoplication was introduced in this Unit as a quality initiative in an attempt to minimize dysphagia and technical errors, and the aim of this study is to report the experience to date, and compare outcomes with the previous 100 cases performed by an experienced team. Methods Eighty patients who underwent laparoscopic Rosetti-Nissen fundoplication and on-table endoscopy (group 2) were compared with 100 consecutive prior cases (group 1). Patients were prospectively evaluated and had pre- and postoperative symptom scoring and analysis of complications (all patients), and manometry and 24-h pH testing in 120 patients (60 in each group). Results Both groups were similar with respect to demographics, esophagitis, pH score, and dysmotility. No bougie was used in either group. On-table endoscopy resulted in technical modifications in 4 (5%) patients. Early grade 2 or 3 dysphagia was evident in 4 (5%) patients in group 2, compared with 15 (15%) in group 1 (p < 0.001). Late dysphagia was evident in one patient (1.5%) in group 2 compared with 7 (7%) in group 1 (p < 0.05). Dilatation was performed in four patients (5%) in group 2, compared with 11 (11%) in group 1 (p < 0.05). Conclusions These data suggest that on-table endoscopy may be a useful quality assurance adjunct in laparoscopic anti-reflux surgery, in particular, reducing the incidence of dysphagia and reinterventions.  相似文献   
35.
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   
36.
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   
37.
38.
39.
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   
40.

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   
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