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   178158篇
  免费   34517篇
  国内免费   2456篇
耳鼻咽喉   5481篇
儿科学   6089篇
妇产科学   2766篇
基础医学   6996篇
口腔科学   2078篇
临床医学   29205篇
内科学   52982篇
皮肤病学   7808篇
神经病学   18130篇
特种医学   7498篇
外国民族医学   3篇
外科学   45123篇
综合类   894篇
现状与发展   72篇
一般理论   66篇
预防医学   9601篇
眼科学   3918篇
药学   2796篇
中国医学   26篇
肿瘤学   13599篇
  2024年   518篇
  2023年   4842篇
  2022年   1294篇
  2021年   3449篇
  2020年   6212篇
  2019年   2542篇
  2018年   7852篇
  2017年   7665篇
  2016年   8795篇
  2015年   8845篇
  2014年   16169篇
  2013年   16764篇
  2012年   7325篇
  2011年   7456篇
  2010年   11357篇
  2009年   15149篇
  2008年   7670篇
  2007年   6029篇
  2006年   8456篇
  2005年   5957篇
  2004年   4970篇
  2003年   3802篇
  2002年   3913篇
  2001年   4078篇
  2000年   3234篇
  1999年   3499篇
  1998年   4014篇
  1997年   3809篇
  1996年   3674篇
  1995年   3527篇
  1994年   2208篇
  1993年   1822篇
  1992年   1607篇
  1991年   1652篇
  1990年   1284篇
  1989年   1374篇
  1988年   1192篇
  1987年   1053篇
  1986年   1048篇
  1985年   906篇
  1984年   778篇
  1983年   738篇
  1982年   790篇
  1981年   672篇
  1980年   584篇
  1979年   441篇
  1978年   471篇
  1977年   491篇
  1975年   364篇
  1972年   364篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
Objective: Impacts of mediastinal lymph node dissection on a patient’s course after pulmonary resection is unclear in octogenarians with non-small cell lung cancer. Methods: Retrospectively identified subjects included 39 octogenarians and 1 nonagenarian, with grades according to the Charlson Comorbidity Index ranging from only 0 to 2. We performed mediastinal lymph node dissection in 19 patients (D group), and just lymph node sampling biopsy in the other 21 (S group). We compared clinicopathologic features and outcome after surgery between both groups. Results: Deterioration of performance status at the time of discharge, evident in 17 patients overall, was significantly more frequent in the D group. Postoperative complications occurred in 27 patients overall and there was no significant difference between the two groups. Survival rates in younger patients at 1, 3, and 5 years were 86, 59, and 49%, respectively; in octogenarians these were 83, 58, and 42% (no significant difference). Nor did survival differ significantly by surgical management of mediastinal lymph nodes; 1-, 3-, and 5-year survival rates were 94, 63, and 40%, respectively in the D group and 78, 66, and 43%, respectively in the S group. Conclusion: Octogenarians with non-small cell lung cancer should be treated by urgent pulmonary resection whenever possible. Since mediastinal lymph node dissection has little effect on long-term survival or the carried risk of worsening performance status at discharge, pulmonary resection without complete mediastinal lymph node dissection should be considered.  相似文献   
132.
We present a case of intrapulmonary metastasis developing 18 years after complete resection of thymoma. An 8 mm nodule in the lower lobe of the left lung was noted on chest X-ray in a 76-year-old woman who had undergone complete resection of Masaoka’s stage II thymoma 18 years earlier. Since the nodule grew to 17 mm during a 2-year follow-up, wedge resection was performed. The lesion was histologically diagnosed as an intrapulmonary metastasis from thymoma. Extremely late recurrence after complete resection of thymoma is discussed.  相似文献   
133.
134.
OBJECTIVE: The uncinate process (UP) is an important anatomic landmark in frontal recess surgery. Its superior attachment shows great anatomic variability. The agger nasi (AN) cell is another important structure that affects frontal recess anatomy and there is a close neighborhood between them. The aim of this study was to investigate the relationship between superior attachment type of UP and the presence of AN cell. STUDY DESIGN: A retrospective anatomical study. METHOD: Computed tomography scans were evaluated of 486 sides of 243 patients who had had paranasal sinus. In 125 (26%) sides, the superior attachment of the UP could not be identified. In the remaining 361 (74%) sides, the prevalence of superior attachment of UP types and the presence of AN cell in each side were recorded. The results were evaluated with chi2 test. RESULTS: The AN cell was found in 290 (80.3%) of 361 sides. The prevalence of AN cell according to superior attachment of UP types were 79.6% for type 1/2, 90.1% for type 3, 71.4% for type 4, 86.5% for type 5, and 83.3% for type 6. The presence of AN cell according to superior attachment types of UP was not statistically significant (chi2= 3.54, P = 0.315). CONCLUSIONS: The AN cell was found to be present in 80.3% of the cases. However, the relationship between the presence of the AN cell and the superior attachment types of UP was not statistically significant.  相似文献   
135.

Background  

There are no published utilities for the post-anesthesia state obtained by the standard gamble method (SG).  相似文献   
136.
137.
138.
139.
140.
OBJECTIVES: Physicians commonly use etomidate for adult rapid-sequence intubation (RSI), but the manufacturer does not recommend its use for children under 10 years of age due to a lack of data. The authors present their experience with etomidate for pediatric RSI in order to further develop its risk-benefit profile in this age group. METHODS: Trained abstractors reviewed the medical records for all children under 10 years old who received etomidate for RSI between July 1996 and April 2001. RESULTS: 105 children, with an average age of 3 (+/-2.9) years, received a median dose of 0.32 (+/-0.12) mg/kg of etomidate. The systolic blood pressure increased an average of 4 mm Hg (95% CI = -3.3 to 9.2); the diastolic blood pressure increased 7 mm Hg (95% CI = -3.1 to 11) within 10 minutes of receiving etomidate. The heart rate increased an average of 10 beats/min (95% CI = 4.0 to 17.4). Complications included three patients who vomited within 10 minutes of etomidate administration. There were no cases of documented myoclonus, status epilepticus, or new-onset seizures. Thirty-eight patients received corticosteroids during the hospital course, none for suspected adrenal insufficiency. Three patients died, all from severe brain injury. CONCLUSIONS: In children less than 10 years old, etomidate seems to produce minimal hemodynamic changes, and appears to have a low risk of clinically important adrenal insufficiency, myoclonus, and status epilepticus. The association between etomidate and emesis (observed in less than 3% of enrolled patients) remains unclear. For clinical situations in which minimal blood pressure changes during RSI are critical, etomidate appears to have a favorable risk-benefit profile for children under 10 years old.  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