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   25335篇
  免费   635篇
  国内免费   466篇
耳鼻咽喉   813篇
儿科学   306篇
妇产科学   337篇
基础医学   577篇
口腔科学   1062篇
临床医学   1206篇
内科学   2088篇
皮肤病学   118篇
神经病学   789篇
特种医学   461篇
外科学   12305篇
综合类   2378篇
一般理论   1篇
预防医学   676篇
眼科学   470篇
药学   859篇
  9篇
中国医学   255篇
肿瘤学   1726篇
  2023年   274篇
  2022年   550篇
  2021年   897篇
  2020年   573篇
  2019年   2310篇
  2018年   2080篇
  2017年   1203篇
  2016年   413篇
  2015年   518篇
  2014年   1165篇
  2013年   1001篇
  2012年   1015篇
  2011年   1091篇
  2010年   903篇
  2009年   870篇
  2008年   838篇
  2007年   817篇
  2006年   654篇
  2005年   555篇
  2004年   483篇
  2003年   515篇
  2002年   435篇
  2001年   412篇
  2000年   360篇
  1999年   324篇
  1998年   281篇
  1997年   208篇
  1996年   147篇
  1995年   146篇
  1994年   109篇
  1993年   81篇
  1992年   63篇
  1991年   57篇
  1990年   52篇
  1989年   59篇
  1988年   52篇
  1987年   58篇
  1985年   521篇
  1984年   511篇
  1983年   378篇
  1982年   451篇
  1981年   411篇
  1980年   425篇
  1979年   356篇
  1978年   339篇
  1977年   199篇
  1976年   369篇
  1975年   315篇
  1974年   280篇
  1973年   255篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

Background

The objective of the study was to evaluate the outcomes of clinically localized prostate cancer treated with prostatectomy versus radiation therapy within the context of a prospective prostate cancer screening study.

Patients and Methods

Within the PLCO (Prostate, Lung, Colorectal, and Ovary) trial, patients who were diagnosed with clinically localized prostate cancer and subsequently received treatment with prostatectomy or radiation therapy (with or without hormonal treatment) were included. Univariate and multivariate Cox regression analyses were then performed to determine factors affecting overall and prostate cancer-specific survival. Factors with P < .05 in univariate analysis were included in the multivariate analysis.

Results

A total of 3953 patients were included in the current analysis. These included 2044 patients treated with prostatectomy and 1909 patients treated with radiation therapy with or without hormonal treatment. In an adjusted multivariate analysis for factors affecting overall survival, prostatectomy was associated with better overall survival compared with radiation therapy (hazard ratio, 0.548; 95% confidence interval [CI], 0.440- 681; P < .001). Likewise, in an adjusted multivariate analysis for factors affecting prostate cancer-specific survival, prostatectomy was associated with better prostate cancer-specific survival compared with radiation therapy (hazard ratio, 0.485; 95% CI, 0.286- 0.822; P = .007). Similar findings were found with propensity score matching and repeating the same analyses on the post-matching cohort.

Conclusion

Prostatectomy seems to predict better overall and prostate cancer-specific survival compared with radiation therapy among patients with clinically localized prostate cancer diagnosed within the PLCO trial.  相似文献   
2.
3.
Haemophilia is a common cause of genetically inherited bleeding disorders. Pseudotumours occur in 1–2 % of persons with severe forms of haemophilia. These are a result of repeated haemorrhage into soft tissues, subperiosteum or a site of bone fracture with inadequate resorption of the extravasated blood. There are a number of therapeutic alternatives for this dangerous condition: surgical removal, percutaneous management, irradiation, embolization etc. In this case report, we describe the natural history, clinical course and successful surgical management of a patient with haemophilia who presented with a massive pseudotumour. We also briefly review the relevant literature on the various therapeutic modalities that have been implemented in the management of this rare complication. Though surgeons may be averse to operate on haemophiliacs, primary surgical management as done in our case may prove to be the definitive treatment option for such patients.  相似文献   
4.
IntroductionEndoscopic surveillance guidelines for patients with repaired esophageal atresia (EA) rely primarily on expert opinion. Prior to embarking on a prospective EA surveillance registry, we sought to understand EA surveillance practices within the Eastern Pediatric Surgery Network (EPSN).MethodsAn anonymous, 23-question Qualtrics survey was emailed to 181 physicians (surgeons and gastroenterologists) at 19 member institutions. Likert scale questions gauged agreement with international EA surveillance guideline-derived statements. Multiple-choice questions assessed individual and institutional practices.ResultsThe response rate was 77%. Most respondents (80%) strongly agree or agree that EA surveillance endoscopy should follow a set schedule, while only 36% claimed to perform routine upper GI endoscopy regardless of symptoms. Many institutions (77%) have an aerodigestive clinic, even if some lack a multi-disciplinary EA team. Most physicians (72%) expressed strong interest in helping develop evidence-based guidelines.ConclusionsOur survey reveals physician agreement with current guidelines but weak adherence. Surveillance methods vary greatly, underscoring the lack of evidence-based data to guide EA care. Aerodigestive clinics may help implement surveillance schedules. Respondents support evidence-based protocols, which bodes well for care standardization. Results will inform the first multi-institutional EA databases in the United States (US), which will be essential for evidence-based care.Level of EvidenceThis is a prognosis study with level 4 evidence.  相似文献   
5.

Objectives

Iatrogenic injury of the Profunda Femoris Artery (PFA) at time of hip fixation surgery can increase morbidity and mortality and prolong the hospital stay. This is an injury that tends to pass unnoticed as a cause of postoperative deterioration despite being frequently reported in the literature. Our study aims to describe the anatomy of the PFA in relation to the medial femoral cortex with specific emphasis on its orientation relative to the position of a sliding hip screw side plate construct. By doing so we are able to present clear guidance to orthopaedic surgeons on how to avoid iatrogenic PFA injury at the time of hip fracture fixation.

Methods

Using Computed Tomography Angiographic (CTA) studies, the course of the PFA in relation to the medial femoral cortex was traced in 44 patients (28 males and 16 females) with mean age of 65.6 years. Coronal and axial CT sections were cross-linked to specify the position of the PFA at 1?cm intervals.

Results

The course of the artery could be divided into three parts relative to a fixed reference point. Proximal and distal parts of the artery were in a safer position in comparison to the middle part of the artery that was found very close to the femoral cortex and along the coronal axis of the femur (mean angle 2.9° from the femoral coronal axis and 13.8?mm from the medial femoral cortex). Using the commercially available side plate constructs, this part of the artery corresponded to the distal part of the plate (third and fourth holes).

Conclusion

Special attention needs to be practiced by the operating surgeon while drilling into the third and fourth holes of the side plate.  相似文献   
6.
7.

BACKGROUND CONTEXT

Health-related quality of life (HRQOL) parameters have been shown to be reliable and valid in patients with adult spinal deformity (ASD). Minimum clinically important difference (MCID) has become increasingly important to clinicians in evaluating patients with a threshold of improvement that is clinically relevant.

PURPOSE

To calculate MCID and minimum detectable change (MDC) values of total scores of the Core Outcome Measures Index (COMI), Oswestry Disability Index (ODI), Physical Component Summary (PCS), Mental Component Summary (MCS) of the Short Form 36 (SF-36), and Scoliosis Research Society 22R (SRS-22R) in surgically and nonsurgically treated ASD patients who have completed an anchor question at pretreatment and 1-year follow-up.

STUDY DESIGN/SETTING

Prospective cohort.

PATIENT SAMPLE

Surgical and nonsurgical patients from a multicenter ASD database.

OUTCOME MEASURES

Self-reported HRQOL measures (COMI, ODI, SF-36, SRS-22R, and anchor question).

METHODS

A total of 185 surgical and 86 nonsurgical patients from a multicenter ASD database who completed pretreatment and 1-year follow-up HRQOL scales and the anchor question at the first year follow-up were included. The anchor question was used to determine MCID for each HRQOL measure. MCIDs were calculated by an anchor-based method using latent class analysis (LCA) and MDCs by a distribution-based method.

RESULTS

All differences between means of baseline and first year postoperative total score measures for all scales demonstrated statistically significant improvements in the overall population as well as the surgically treated patients but not in the nonsurgical group. The calculated MDC and MCID values of HRQOL parameters in the entire study population were 1.34 and 2.62 for COMI, 10.65 and 14.31 for ODI, 6.09 and 7.33 for SF-36 PCS, 6.14 and 4.37 for SF-36 MCS, and 0.42 and 0.71 for SRS-22R. The calculated MCID values for surgical and non-surgical treatment groups were 2.76 versus 1.20 for COMI, 14.96 versus 2.45 for ODI, 7.83 versus 2.15 for SF-36 PCS, 5.14 versus 2.03 for SF-36 MCS, and 0.94 versus 0.11 for SRS-22R; the MDC values for surgical and nonsurgical treatment groups were 1.22 versus 1.51 for COMI, 10.27 versus 9.45 for ODI, 5.16 versus 6.77 for SF-36 PCS, 6.05 versus 5.67 for SF-36 MCS, and 0.38 versus 0.43 for SRS-22R.

CONCLUSIONS

This study has demonstrated that MCID calculations for the HRQOL scales in ASD using LCA yield values comparable to other studies that had used different methodologies. The most important finding was the significantly different MCIDs for COMI, ODI, SF-36 PCS and SRS-22 in the surgically and nonsurgically treated cohorts. This finding suggests that a universal MCID value, inherent to a specific HRQOL for an entire cohort of ASD may not exist. Use of different MCIDs for surgical and nonsurgical patients may be warranted.  相似文献   
8.

Background

Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.

Methods

This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.

Results

A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.

Conclusion

Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy.  相似文献   
9.
Background. It has been reported that gender differences in cardiovascular outcomes found in adults also are present in children who undergo surgical repair for congenital heart disease. Methods. California statewide hospital discharge data 1989–99 were used to study outcomes in children <18 years undergoing cardiac surgery. Hospital discharge data were linked to death registry data to study postdischarge death within 30 days of discharge. We used logistic regression to evaluate the effect of gender on mortality controlling for age, race and ethnicity, type of insurance, household income, date and month of surgery, type of admission, hospital case volume, and various types of procedures. Results. There were 25 402 cardiac surgery cases with 1505 in‐hospital deaths (mortality rate of 5.92%). An additional 37 deaths occurred within 30 days after hospital discharge. Crude mortality rates for males (5.99%) and females (5.84%) were not significantly different. However, fewer neonates were female and females underwent a higher proportion of low‐risk procedures than males. Logistic regression revealed that females, compared with males, had a significantly higher odds ratio (OR) for in‐hospital mortality (OR = 1.18, P < .01) and overall (up to 30 days post discharge) mortality (OR = 1.18, P < .01). The risk‐adjusted length of hospital stay was similar between females and males while charges per hospital day were slightly higher in females than males. The prevalence of Down syndrome, pulmonary hypertension, and failure to thrive were higher in females. Conclusions. Female gender is associated with an 18% higher in‐hospital and 30‐day postdischarge mortality as compared with male gender. There was no difference in length of hospital stay between males and females. The mechanism by which female gender acts as a risk factor requires further investigation.  相似文献   
10.
There is insufficient evidence that the surgical treatment of asymptomatic infrarenal aneurysms > 5.5 cm. is beneficial to patients. This is the result of serious complications of aneurysm surgery and the dearth of information from randomized trials. Based on evidence from the literature we defined scenarios and translated data into natural frequency trees to improve understanding of the uncertainty of help versus harm due to treatment of aneurysms. Our analysis shows that the majority of patients can expect little on longevity from surgery while they are at risk of dying from surgery or suffering from serious morbidity. We conclude that, as long as uncertainty persist, patients should be treated in hospitals that can show very low surgical mortality and major morbidity rates. To further resolve the problem of uncertainty randomized trials for larger aneurysms should be performed. Important issues to discuss are the lower and upper limits of the diameter of the aneurysms and the age and risk profiles of the patients to be included in such trials.  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