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   2380篇
  免费   154篇
  国内免费   4篇
耳鼻咽喉   20篇
儿科学   112篇
妇产科学   53篇
基础医学   282篇
口腔科学   44篇
临床医学   284篇
内科学   484篇
皮肤病学   126篇
神经病学   165篇
特种医学   135篇
外科学   294篇
综合类   30篇
一般理论   1篇
预防医学   195篇
眼科学   9篇
药学   125篇
中国医学   2篇
肿瘤学   177篇
  2023年   27篇
  2022年   59篇
  2021年   103篇
  2020年   44篇
  2019年   76篇
  2018年   82篇
  2017年   65篇
  2016年   68篇
  2015年   73篇
  2014年   85篇
  2013年   129篇
  2012年   140篇
  2011年   164篇
  2010年   97篇
  2009年   69篇
  2008年   123篇
  2007年   110篇
  2006年   117篇
  2005年   97篇
  2004年   93篇
  2003年   96篇
  2002年   70篇
  2001年   23篇
  2000年   14篇
  1999年   23篇
  1998年   26篇
  1997年   36篇
  1996年   33篇
  1995年   36篇
  1994年   27篇
  1993年   39篇
  1992年   11篇
  1991年   17篇
  1990年   21篇
  1989年   23篇
  1988年   26篇
  1987年   26篇
  1986年   21篇
  1985年   18篇
  1984年   11篇
  1983年   10篇
  1982年   11篇
  1981年   21篇
  1980年   12篇
  1979年   5篇
  1978年   7篇
  1977年   8篇
  1976年   14篇
  1975年   5篇
  1927年   3篇
排序方式: 共有2538条查询结果,搜索用时 15 毫秒
91.
Voakes  JB; Jones  SE; McKelvey  EM 《Blood》1981,57(1):186-188
Thirty-two patients treated on consecutive Southwest Oncology Group (SWOG) protocols for malignant lymphoma were subsequently diagnosed as having lymphoblastic lymphoma. Combination chemistry, usually adriamycin-based, produced complete responses (CR) in 17 patients (53%). Median survival was 15 mo. Patients achieving a CR survival significantly longer than patients with partial or no response (p < 0.01). Ten of 24 patients not receiving central nervous system (CNS) prophylaxis developed leptomeningeal lymphoma while none of the seven patients who received prophylactic intrathecal cytosine arabinoside or methotrexate developed CNS lymphoma (p = 0.04). Implications of these results for planning future treatment programs of lymphoblastic lymphoma are discussed.  相似文献   
92.
Electrographic seizures are common in neonates with hypoxic-ischemic encephalopathy, but detailed data are not available regarding seizure incidence during therapeutic hypothermia. The objective of this prospective study was to determine the incidence and timing of electrographic seizures in term neonates undergoing whole-body therapeutic hypothermia for hypoxic-ischemic encephalopathy as detected by conventional full-array electroencephalography for 72 hours of therapeutic hypothermia and 24 hours of normothermia. Clinical and electroencephalography data were collected from 26 consecutive neonates. Electroencephalograms were reviewed by 2 pediatric neurophysiologists. Electrographic seizures occurred in 17 of 26 (65%) patients. Seizures were entirely nonconvulsive in 8 of 17 (47%), status epilepticus occurred in 4 of 17 (23%), and seizure onset was in the first 48 hours in 13 of 17 (76%) patients. Electrographic seizures were common, were often nonconvulsive, and had onset over a broad range of times in the first days of life.  相似文献   
93.
King BF  Kindig RC  Noah WH  Tuteur PG 《The Internist》1990,31(7):suppl 3-suppl15
The primary objective in medical training remains skill development in the delivery of medical care through the understanding of bedside data collection, natural history of disease, use of diagnostic tools and the influence of therapy--all applied to a specific patient. More recently, also considered important is training on the broader issues of health care delivery and public policy, especially since the environment of medicine is changing rapidly. With limited curricular time these issues must compete with the traditional and important clinical training. To evaluate how these subjects have been included in internal medicine training, the Resident Physicians Section (RPS) of the American Society of Internal Medicine (ASIM) sponsored a survey of United States internal medicine chief residents which was conducted by the Internal Medicine Center to Advance Research and Education (IMCARE). The objectives of the study were to 1) study the extent of training on health care delivery and public policy issues offered to residents by internal medicine residency programs; 2) assess training opportunities now available; and 3) determine areas of study not fulfilling perceived needs. The questionnaire contained 12 questions. Chief residents rated the 1) quality of their program in preparing residents on health care delivery, public policy issues and practice management; 2) level of instruction provided on 12 topics; and 3) degree of priority these same topics should have. Respondents were asked to identify 1) any other relevant areas their residency program covered particularly well; 2) the amount of time which should be devoted to these socioeconomic topics in each year of training; and 3) the most appealing formats for learning about these topics. Despite the rapidly growing influence of socioeconomic issues on medical practice, many chief residents perceive that important topics are not being addressed adequately. This study provides information on areas addressed well and topics that should receive greater attention. Recommendations are made for further studies and strategies to increase the emphasis on socioeconomic topics during medical education.  相似文献   
94.
The aim of this study was to evaluate the effect of hormone replacement therapy (HRT) on the expression of Ki-67, bcl-2 and c-erb.B2 in endometrial polyps during menopause. Sixteen patients using HRT and 24 untreated controls with endometrial polyps were enrolled in this study. Polypectomy was carried out by hysteroscopy. The presence of c-erb.B2, bcl-2 and Ki-67 expression was determined by immunohistochemistry. HRT was found to decrease Ki-67 and bcl-2 expression in endometrial polyps without affecting the c-erb.B2 staining reaction. HRT may cause endometrial polyp involution by decreasing proliferation and stimulating apoptosis.  相似文献   
95.
Patients born with congenital right ventricular outflow tract lesions are faced with invasive procedures to establish hemodynamic and physiological stability. Commonly, multiple subsequent surgical procedures are required due to deterioration of a previous repair. These procedures carry additive risks of mortality and morbidity. Less aggressive procedures with accompanying lower risk is ideal. Success in percutaneously placing a transcatheter valve has previously been reported; however, continued safety and efficacy of any technique needs continual assessment. We developed a model for preclinical evaluation of a percutaneous placement of a pulmonic transcatheter valve in adult sheep, including preoperative, surgical, and postoperative techniques for long-term evaluation. Adult sheep were assessed and determined to be acceptable for study enrollment. Perioperative antibiotics and analgesics were given prior to a left thoracotomy. A Medtronic, Hancock 1 valve conduit was inserted for reconstruction of the right ventricular outflow tract. The Hancock 1 valve conduit alone represented the control group and the test animals comprised the addition of a Melody? transcatheter pulmonary valve (TPV), within the Hancock 1 valve conduit. Fifteen adult sheep survived the surgical implant procedure with no perioperative mortality. There were four early postoperative deaths, three due to infection and one due to heart failure, secondary to intraoperative heart block. The remaining 11 animals remained healthy, gained weight, and survived to termination at 5 months. An initial definite-sized valve conduit was implanted, followed by inserting a single size TPV, which allowed a more accurate physiological assessment of any chosen valve. Our developed adult sheep model for percutaneous TPV implantation for right ventricular outflow tract lesions was successful for long-term assessment by utilizing our preoperative, surgical, and postoperative techniques.  相似文献   
96.
BackgroundIn 2015, the U.S. Soccer Federation banned heading for players aged 10–13.Purpose/QuestionTo assess the change in proportion of children aged 10–13 playing soccer in the US presenting to an Emergency Department (ED) with a concussion in relation to any other injury before and after the ban.MethodsAnalysis was restricted to soccer athletes between 10–13 years that reported to a National Electronic Injury Surveillance System (NEISS) participating hospital ED following injury in 2013–2014 and 2016–2017. Multivariable logistic regression was performed to assess the association between year of injury and concussion diagnosis in relation to other injury diagnosis after adjusting for age, sex, and ethnicity.ResultsConcussion in relation to other injuries showed a significant increase in 2016–2017 when compared to 2013–2014 after adjustment (OR= 1.286, 95%CI = 1.090–1.517).ConclusionsThese results suggest that banning heading may not reduce concussion within this population. However, significant confounders, including increased reporting, were not controlled for.  相似文献   
97.
BackgroundComplications arising from laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) are not insignificant and can necessitate additional invasive interventions or reoperations.ObjectivesIn this study, we identify early complications that result in nonoperative and operative interventions after LSG and LRYGB, the timeframe within which to expect them, and factors that influence the likelihood of their occurrence.SettingMulti-institutional database from across North America.MethodsData for this study were obtained from Metabolic and Bariatric Accreditation and Quality Improvement Program participant use files for 2015 and 2016. Statistical analysis was performed using STATA 15. Univariate analysis using Χ2 for categoric data and independent t test for continuous data was performed to determine between group differences. Multivariable logistic regression analysis was used to identify predictors of operative and nonoperative reinterventions.ResultsIn 2015 and 2016, 243,747 underwent LRYGB or LSG, of which 3013 (1.24%) required a second operative procedure and 1536 (0.63%) required an invasive but nonoperative intervention. Complications occurred in 5.48% of LRYGB patients and 2.28% of LSG patients, the most common of which was bleeding. LSG was associated with far fewer nonoperative and operative interventions (.85% versus 2.2%, respectively) than LRYGB (.67% versus 2.5%). Renal insufficiency, including dialysis dependency, was an important predictor of reoperations among bariatric surgery patients. This was also true of nonoperative interventions; however, history of pulmonary embolism, and use of therapeutic anticoagulation were marginally stronger predictors.ConclusionsIn a representative, multinational sample, operative and nonoperative interventions were half as likely among LSG patients compared with LRYGB; however, overall rates still remained low. These findings, in conjunction with new efficacy data demonstrating comparable long-term weight loss between LRYGB and LSG, provide further support for the safety, effectiveness, and cost efficiency of LSG.  相似文献   
98.

Background

Chemotherapy may exert immunomodulatory effects, thereby combining favorably with the immune checkpoint blockade. The pharmacodynamic effects of such combinations, and potential predictive biomarkers, remain unexplored.

Objective

To determine the safety, efficacy, and immunomodulatory effects of gemcitabine and cisplatin (GC) plus ipilimumab and explore the impact of somatic DNA damage response gene alterations on antitumor activity.

Design, setting, and participants

Multicenter single arm phase 2 study enrolling 36 chemotherapy-naïve patients with metastatic urothelial cancer. Peripheral blood flow cytometry was performed serially on all patients and whole exome sequencing of archival tumor tissue was performed on 28/36 patients.

Intervention

Two cycles of GC followed by four cycles of GC plus ipilimumab.

Outcome measurements and statistical analysis

The primary endpoint was 1-yr overall survival (OS). Secondary endpoints included safety, objective response rate, and progression-free survival.

Results and limitations

Grade ≥3 adverse events occurred in 81% of patients, the majority of which were hematologic. The objective response rate was 69% and 1-yr OS was 61% (lower bound 90% confidence interval: 51%). On exploratory analysis, there were no significant changes in the composition and frequency of circulating immune cells after GC alone. However, there was a significant expansion of circulating CD4 cells with the addition of ipilimumab which correlated with improved survival. The response rate was significantly higher in patients with deleterious somatic DNA damage response mutations (sensitivity = 47.6%, specificity = 100%, positive predictive value = 100%, and negative predictive value = 38.9%). Limitations are related to the sample size and single-arm design.

Conclusions

GC + ipilimumab did not achieve the primary endpoint of a lower bound of the 90% confidence interval for 1-yr OS of >60%. However, within the context of a small single-arm trial, the results may inform current approaches combining chemotherapy plus immunotherapy from the standpoint of feasibility, appropriate cytotoxic backbones, and potential predictive biomarkers. Trial registration: ClinicalTrials.gov NCT01524991.

Patient summary

Combining chemotherapy and immune checkpoint blockade in patients with metastatic urothelial cancer is feasible. Further studies are needed to refine optimal combinations and evaluate tests that might identify patients most likely to benefit.  相似文献   
99.

BACKGROUND:

Selecting candidates for plastic surgery residency training remains a challenge. In the United States, academic measures (United States Medical Licensing Exam Step I scores, medical school class rank and publications) are used as primary criteria for candidate selection for residency. In contrast, Canadian medical education de-emphasizes academic measures by using a pass-fail grading system. As a result, choosing residents from many qualified applicants may pose a challenge for Canadian programs without objective measures of academic success.

METHODS:

A 25-question online survey was distributed to program directors of Canadian plastic surgery residency-training programs. Program directors commented on number of yearly residents and applicants; application sections (ranked in importance using a Likert scale); interview invitation and rank-order list determination; and their satisfaction with the selection process.

RESULTS:

Ten Canadian plastic surgery program directors responded (90.9% response rate). The most important application components determining invitation to interview were letters of reference from a plastic surgeon (mean importance of 5.0 on the Likert scale), clinical electives in plastic surgery (mean 4.6) and electives with their program (mean 4.5). Applicants invited for interview were assessed on the quality of their responses to questions, maturity and personality. The majority of program directors agreed that a clinical elective with their program was important for consideration on their rank-order list. Program directors were neutral on their satisfaction with the selection process.

CONCLUSION:

Canadian plastic surgery residency programs emphasize clinical electives with their program and letters of reference from colleagues when selecting applicants for interviews. In contrast to their American counterparts, Canadian program directors rely on clinical interactions with prospective residents in the absence of objective academic measures.  相似文献   
100.
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