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   15521篇
  免费   1205篇
  国内免费   37篇
耳鼻咽喉   297篇
儿科学   321篇
妇产科学   217篇
基础医学   1965篇
口腔科学   520篇
临床医学   1485篇
内科学   3129篇
皮肤病学   205篇
神经病学   1722篇
特种医学   546篇
外科学   2169篇
综合类   244篇
一般理论   10篇
预防医学   1415篇
眼科学   265篇
药学   1040篇
  1篇
中国医学   9篇
肿瘤学   1203篇
  2023年   89篇
  2022年   145篇
  2021年   271篇
  2020年   198篇
  2019年   227篇
  2018年   295篇
  2017年   231篇
  2016年   241篇
  2015年   241篇
  2014年   390篇
  2013年   665篇
  2012年   871篇
  2011年   944篇
  2010年   555篇
  2009年   547篇
  2008年   951篇
  2007年   986篇
  2006年   1033篇
  2005年   978篇
  2004年   966篇
  2003年   974篇
  2002年   960篇
  2001年   173篇
  2000年   117篇
  1999年   149篇
  1998年   217篇
  1997年   198篇
  1996年   198篇
  1995年   162篇
  1994年   143篇
  1993年   108篇
  1992年   113篇
  1991年   108篇
  1990年   106篇
  1989年   77篇
  1988年   94篇
  1987年   82篇
  1986年   89篇
  1985年   98篇
  1984年   126篇
  1983年   139篇
  1982年   165篇
  1981年   141篇
  1980年   153篇
  1979年   73篇
  1978年   114篇
  1977年   91篇
  1976年   96篇
  1974年   71篇
  1972年   60篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
This study examined race and ethnic differences on the Draw A Person: Screening Procedure for Emotional Disturbance (DAP:SPED; Naglieri, McNeish, & Bardos, 1991) for youths 6 though 17 years of age for 2 matched samples. Samples were drawn from the DAP:SPED nationally representative standardization sample and matched on gender, grade, and school classroom. No statistically significant differences were found for big figure, small figure, or shading item composites. A statistically significant difference was found between Black-White pairs on figure omissions but showed a small effect size (d value = .25). Further, no statistically significant differences were found between the DAP:SPED Total T scores for Black and White youth (M = 47.67, SD = 10.09; N =138) or Hispanic and White youth (M = 48.20, SD = 9.56; N = 59), showing very small effect sizes. In addition, equivalence testing showed similarities across race and ethnic pairs for all composites and DAP:SPED total score, lending preliminary support to the DAP:SPED's clinical utility as a measure that yields similar scores across these groups.  相似文献   
5.
Schemes for stimulating adverse drug reporting are described with particular emphasis on a recently introduced Mississippi Adverse Drug Reaction Reporting Programme.  相似文献   
6.
OBJECTIVES: To determine the value of the loss of expression of E-cadherin and cadherin associated molecules as useful markers for both prognosis and chemosensitivity in bladder cancer patients who have undergone radical cystectomy. PATIENTS AND METHODS: In 55 paraffin embedded specimens of radical cystectomy at our hospital from 1982 to 2000, the expression of E-cadherin, alpha-, beta- and gamma-catenin was examined by immunohistochemical staining. To evaluate the prognostic significance of these molecules, Kaplan-Meier survival curves were constructed and a statistical analysis was calculated by a log-rank test. A multivariate test (tumor stage, tumor grade, lymph node metastasis, configuration, the expression of E-cadherin, alpha-, beta- and gamma-catenin) was performed to detect prognostic markers. RESULTS: Normal expression was found in 33 cases (60.0%) for E-cadherin, 29 (52.7%) for alpha-catenin, 31 cases (56.4%) for beta-catenin, and 31 cases (56.4%) for gamma-catenin. The expression patterns for E-cadherin, alpha-, beta- and gamma-catenin were significantly correlated with each other (P < 0.01). Survival analysis showed a significant difference between normal and aberrant expression in each staining. A multivariate analysis revealed that the expression of alpha- catenin was an independent prognostic factor (P = 0.0191). In 23 patients that received adjuvant chemotherapy, there was a significant difference in survival between the normal and aberrant expression of alpha-catenin, but not other molecules. CONCLUSION: Alpha-catenin may not only be a good prognostic marker, but also one of key molecules that determine the chemosensitivities in patients with invasive bladder cancer.  相似文献   
7.
8.
9.
This report looks at outpatient treatment of nasopharyngeal inlet stenosis, a more commonly seen postoperative complication of uvulopalatopharyngoplasty (UPPP). It does not study the effectiveness of the UPPP for treatment of obstructive sleep apnea syndrome (OSAS). The authors evaluated six patients who had a UPPP for OSAS, all of whom developed stenosis in the nasopharyngeal inlet ranging from 14 mm to complete closure. Two patients had failed rotation flap repairs. The carbon dioxide laser was used to treat these patients in the office under a local anesthesia in a staged manner. We now have patients from 3 months to 12 months follow-up who have had stenosis treated successfully. We believe that the postoperative complication of nasopharyngeal inlet stenosis after UPPP can be treated in a safe and cost-effective manner in the office setting.  相似文献   
10.
The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed.  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