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   37324篇
  免费   3889篇
  国内免费   1572篇
耳鼻咽喉   356篇
儿科学   677篇
妇产科学   559篇
基础医学   3540篇
口腔科学   719篇
临床医学   4577篇
内科学   5330篇
皮肤病学   618篇
神经病学   2108篇
特种医学   1087篇
外国民族医学   2篇
外科学   3436篇
综合类   5882篇
现状与发展   17篇
一般理论   25篇
预防医学   3721篇
眼科学   1012篇
药学   4174篇
  56篇
中国医学   2581篇
肿瘤学   2308篇
  2024年   495篇
  2023年   555篇
  2022年   1443篇
  2021年   1859篇
  2020年   1531篇
  2019年   1225篇
  2018年   1372篇
  2017年   1352篇
  2016年   1208篇
  2015年   1621篇
  2014年   1933篇
  2013年   2108篇
  2012年   3143篇
  2011年   3214篇
  2010年   2329篇
  2009年   1986篇
  2008年   2467篇
  2007年   2277篇
  2006年   2037篇
  2005年   1840篇
  2004年   1351篇
  2003年   1258篇
  2002年   1031篇
  2001年   396篇
  2000年   351篇
  1999年   233篇
  1998年   262篇
  1997年   192篇
  1996年   138篇
  1995年   125篇
  1994年   127篇
  1993年   89篇
  1992年   114篇
  1991年   108篇
  1990年   93篇
  1989年   68篇
  1988年   61篇
  1987年   62篇
  1986年   76篇
  1985年   58篇
  1984年   61篇
  1983年   70篇
  1982年   74篇
  1981年   48篇
  1980年   40篇
  1979年   34篇
  1978年   34篇
  1977年   33篇
  1974年   22篇
  1973年   22篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.

Purpose

Chondrosarcoma (CHS) in the spine is relatively rare and minimal information has been published in the literature regarding this subject. The objective of our study was to discuss the factors that may affect outcomes of patients with spinal CHS.

Methods

Univariate and multivariate analyses were performed to identify prognostic factors for recurrence, distant metastasis, and survival of spinal CHS. T test, χ 2 test and rank sum test were used to analyze a single factor for recurrence and metastasis, while survival rate was estimated using the Kaplan–Meier method. Factors with p values of ≤0.1 were subjected to multivariate analyses by binary logistic regression analyses or Cox regression analyses. p Values of ≤0.05 were considered statistically significant.

Results

A total of 98 patients with spinal CHS were included in the study. The mean follow-up period was 49.7 months (range 6–178). Recurrence was detected in 42 patients after initial surgery in our center, while distant metastasis and death occurred in 24 and 32 cases, respectively. The statistical analyses suggested that pathology grade III was closely related with distant metastasis which was an independent prognostic factor for overall survival. Total en bloc spondylectomy could significantly decrease the risk of recurrence, distant metastasis, and death of patients with spinal CHS.

Conclusions

Total en bloc spondylectomy could significantly decrease the risk of recurrence and distant metastasis, and meanwhile improve overall survival of spinal CHS. Distant metastasis which was closely associated with pathology grade III was an adverse prognostic factor for overall survival of spinal CHS.  相似文献   
42.

Objective

Assess factors that influence both the patient and the physician in the setting of minor head injury in adults and the decision-making process around CT utilization.

Methods

This is a convenience sample survey study of adult minor head injury patients (GCS 15) and their physicians regarding factors influencing the decision to use CT to evaluate for intra-cranial haemorrhage. Once a head CT was ordered and before the results were known, both the patient and physician were given a one-page survey asking questions about their concern for injury and rationale for CT use. CT results and surveys were then recorded in a centralized database and analyzed.

Results

584 subjects were enrolled over the 27-month study period. The rate of any intra-cranial haemorrhage was 3.3%. Both the physicians (6% pre-test estimate) and the patients (22% pre-test estimate) over-estimated risk for haemorrhage. Clinical decision rules were not met in 46% of cases where CT was used. Physicians listed an average of 5 factors from a list of 9 that influenced their decision to order CT. Patients listed an average of 1.7 factors influencing their decision to present to the Emergency Department for evaluation. Many patients felt cost (45%) and low risk stratification (34%) should weigh heavily in the decision to use CT. If asked to limit CT utilization, physicians were able to identify a group with less than 2% risk of injury.

Conclusions

Patients with low risk of intra-cranial injury continue to be evaluated by CT. Physician decision-making around the use of CT to evaluate minor head injury is multi-factorial. Shared decision-making between the patient and the physician in a low risk minor head injury encounter shows promise as a method to reduce CT utilization in this low risk cohort.  相似文献   
43.

Background/purpose

NSQIP Pediatric (NSQIP-P) is a robust quality improvement effort. A limitation of the NSQIP process lies in capturing a small proportion of the total case volume. This study examines whether appendectomies captured by NSQIP-P are concordant with all appendectomies, the most commonly captured procedure in 2011.

Methods

We compared case mix and 30-day outcomes between children undergoing an appendectomy who were included in NSQIP (n = 80) and children not captured by NSQIP (n = 276) during 2011 at a tertiary referral children’s hospital. A single surgical case reviewer reviewed all cases using NSQIP-P methodology.

Results

NSQIP-P captured 80 of a total of 356 appendectomies (22%). The case mix was similar between NSQIP and non-NSQIP groups (e.g., 31% of each group had complicated appendicitis). Outcomes were also similar; post-operative occurrences, readmissions and return to the operation room occurred at rates of 7.5% vs. 7.6%, 5% vs. 4.7%, and 3.8% vs. 4.3% respectively.

Conclusion

Although NSQIP-P captured a minority of the total patient population that had an appendectomy, the case mix and outcomes were similar. Our results offer reassurance that NSQIP-P data are representative of the larger population for this procedure. Whether this concordance exists for procedures less commonly performed is unknown and a focus of ongoing work.  相似文献   
44.
45.
46.
47.
48.

Purpose

The purpose of this study was to determine the intravenous dose of carbetocin required to produce effective uterine contraction in 90% of females (ED90) undergoing elective Cesarean delivery (CD) under spinal anesthesia.

Methods

We conducted a double-blind dose-finding study of carbetocin. Forty females undergoing elective CD received carbetocin intravenously upon delivery of the fetus. The dose of carbetocin for each patient was determined according to a biased-coin up-and-down sequential allocation scheme designed to cluster doses close to ED90. The initial dose was 10 μg, with increments/decrements of 5 μg. The anesthesiologist, obstetrician, and patient were blinded to the dose. The obstetrician assessed the uterine tone at one-minute intervals for five minutes after carbetocin administration. In case of unsatisfactory tone, additional uterotonics were administered. The primary outcome was requirement for additional intraoperative uterotonics. Secondary outcomes were postoperative requirement for additional uterotonics within 24 hr of delivery, estimated blood loss and side effects.

Results

The ED90 of carbetocin was 14.8 μg (95% confidence interval 13.7 to 15.8). Thirty-seven patients (92.5%) had adequate uterine tone with no requirement of additional intraoperative uterotonics. Two patients (5%) required postoperative uterotonics within 24 hr. The overall mean (SD) estimated blood loss was 786 (403) mL and the overall incidence of hypotension (decrease in systolic blood pressure ≥ 20% baseline) was 37.5%.

Conclusion

Based on our study, the ED90 of carbetocin at elective CD is less than one-fifth the currently recommended dose of 100 μg. This study was registered at clinicaltrials.gov (NCT-01651130).  相似文献   
49.
50.
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