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   100654篇
  免费   6137篇
  国内免费   437篇
耳鼻咽喉   1113篇
儿科学   2514篇
妇产科学   1782篇
基础医学   12467篇
口腔科学   1755篇
临床医学   10656篇
内科学   20248篇
皮肤病学   1339篇
神经病学   10083篇
特种医学   3900篇
外国民族医学   3篇
外科学   16359篇
综合类   1089篇
一般理论   131篇
预防医学   8227篇
眼科学   2080篇
药学   6489篇
中国医学   105篇
肿瘤学   6888篇
  2023年   563篇
  2022年   935篇
  2021年   2097篇
  2020年   1325篇
  2019年   2098篇
  2018年   2550篇
  2017年   1825篇
  2016年   1986篇
  2015年   2274篇
  2014年   3443篇
  2013年   4726篇
  2012年   7563篇
  2011年   7976篇
  2010年   4583篇
  2009年   4131篇
  2008年   7125篇
  2007年   7450篇
  2006年   7178篇
  2005年   6892篇
  2004年   6717篇
  2003年   6052篇
  2002年   5710篇
  2001年   838篇
  2000年   557篇
  1999年   889篇
  1998年   1220篇
  1997年   924篇
  1996年   749篇
  1995年   682篇
  1994年   589篇
  1993年   579篇
  1992年   443篇
  1991年   399篇
  1990年   325篇
  1989年   291篇
  1988年   277篇
  1987年   278篇
  1986年   241篇
  1985年   277篇
  1984年   305篇
  1983年   252篇
  1982年   333篇
  1981年   282篇
  1980年   221篇
  1979年   93篇
  1978年   128篇
  1977年   107篇
  1976年   78篇
  1975年   66篇
  1973年   69篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
132.
Objectives/Hypothesis: Vocal rehabilitation of patients who have undergone laryngectomy is best accomplished by a tracheoesophageal puncture. Optimal function of the prosthesis requires an adequate stoma. Patients with tracheostomal stenosis require revision of the stoma if vocal rehabilitation is to take place. Revision and tracheoesophageal placement are usually done as two separate procedures. Creating a tracheoesophageal fistula at the time of stomal revision has not been addressed in the literature. Study Design: Prospective analysis and follow-up of 10 patients undergoing simultaneous tracheoesophageal puncture and stomal revision for tracheostomal stenosis between 1991 and 1996. Methods: Ten patients were reviewed. An inferiorly based V-Y advancement flap was used so as not to interfere with the tracheoesophageal puncture. All patients had received radiation prior to revision and tracheoesophageal puncture. Patients were followed for a minimum of 2 years (range, 2–6 y; median, 3 y). Results: All patients maintained an adequate stoma without stenting. Eight of ten patients (80%) developed and maintained good tracheoesophageal speech. Two patients had their speech fistulas removed. There were no intraoperative or postoperative complications. Conclusions: Creation of a tracheoesophageal fistula at the time of stomal revision allows for vocal rehabilitation with a single visit to the operating room. Laryngoscope, 108:1509-1513, 1998  相似文献   
133.
The purpose of this study was to evaluate the influence of composition and deformation of biomedical stainless steels on mechanical properties, magnetic properties, and MRI artifacts. Type 304 and Type 316L samples were prepared using standard wire-drawing techniques. Mechanical properties were determined using standard test methods. The amount of ferromagnetic phase present was estimated using a Severn Gage and x-ray diffraction. Magnetic field attraction and artifacts were determined using previously described techniques. The strength of both steels increased significantly with increasing deformation. None of the type 316L wires transformed to the magnetic phase. The amount of magnetic phase in the type 304 wires increased with increasing deformation. There was no magnetic field attraction, and artifacts were minimal for all of type 316L wires and the undeformed type 304 wire. Deflection and artifacts were significant for the deformed type 304 stainless steel. These results provide guidance regarding the use of type 304 and type 316L stainless steels for bioimplants. In this regard, type 316L stainless steel seems to be a more acceptable material with respect to MR compatibility.  相似文献   
134.
135.
136.
137.
During a 26-year period (1961-1987), a total of 18 patients with primary non-Hodgkin's lymphoma (NHL) of the paranasal sinuses and nasal cavity received radiation therapy at (University of California at Los Angeles) UCLA Medical Center. At the time of diagnosis and using the available diagnostic methods, none of these patients had clinically detectable disease beyond the paranasal sinuses. All 18 patients were staged IE by the Ann-Arbor system. When the patients were staged according to the AJC staging system from epithelial tumors, half presented with advanced T3-4 disease. Diffuse histiocytic lymphoma was the most common histology (eight cases) and maxillary sinus, the most common site of origin (11 cases). All nine T1-2 tumors received radiation therapy alone, while radiation and chemotherapy was used in seven of nine advanced T3-4 staged tumors. The mean follow-up was 71 months. At last follow-up, eight of nine T1-2 patients were rendered disease-free. In contrast, only four of nine T3-4 patients had long-term disease-free survival. Seventy-five percent of the failure occurred within 2 years. Radiation therapy alone achieves high local control in small tumors (T1-2), while large tumors (T3-4) require aggressive combined treatment, i.e., radiation and chemotherapy.  相似文献   
138.
Psychophysical functions are used to characterize both normal perception and altered perception among patients with neglect, yet the reliability of these functions is rarely examined. The present study examined two-week, test-retest reliability for power functions derived from line bisection data among 58 normal, young and old, male and female subjects. Power function exponents and constants were, at best, moderately reliable over time. The size of the exponent tended to decrease at retesting. Reliability coefficients varied by age and gender; they were highly significant for young men, marginally significant for older men, and non-significant for women. Race influenced reliability as coefficients were significant for Caucasian subjects but not for African American subjects. Age and gender effects in this study parallel those in the literature on pseudoneglect, and they may reflect hemispheric differences in visuo-spatial processing, magnitude estimation, or both.  相似文献   
139.
140.
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