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   119407篇
  免费   10319篇
  国内免费   7092篇
耳鼻咽喉   1262篇
儿科学   1805篇
妇产科学   2394篇
基础医学   13851篇
口腔科学   2260篇
临床医学   15829篇
内科学   18246篇
皮肤病学   1022篇
神经病学   6360篇
特种医学   4107篇
外国民族医学   45篇
外科学   12607篇
综合类   17858篇
现状与发展   24篇
一般理论   20篇
预防医学   7661篇
眼科学   3125篇
药学   12347篇
  74篇
中国医学   6048篇
肿瘤学   9873篇
  2024年   360篇
  2023年   1747篇
  2022年   4451篇
  2021年   5813篇
  2020年   4166篇
  2019年   3744篇
  2018年   4059篇
  2017年   3449篇
  2016年   3307篇
  2015年   5202篇
  2014年   6479篇
  2013年   5925篇
  2012年   8807篇
  2011年   9595篇
  2010年   5982篇
  2009年   4622篇
  2008年   6256篇
  2007年   6424篇
  2006年   6211篇
  2005年   6442篇
  2004年   4290篇
  2003年   3765篇
  2002年   3363篇
  2001年   2693篇
  2000年   2845篇
  1999年   2858篇
  1998年   1659篇
  1997年   1542篇
  1996年   1373篇
  1995年   1220篇
  1994年   1027篇
  1993年   663篇
  1992年   1030篇
  1991年   838篇
  1990年   705篇
  1989年   624篇
  1988年   621篇
  1987年   551篇
  1986年   430篇
  1985年   342篇
  1984年   217篇
  1983年   166篇
  1982年   92篇
  1981年   103篇
  1980年   86篇
  1979年   123篇
  1978年   60篇
  1977年   61篇
  1975年   49篇
  1974年   52篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
41.
42.
Amyloidosis is a systemic disease that usually occurs in the gastrointestinal tract or in muscular or adipose tissue. Primary amyloidosis of the urinary bladder is a rare disease that can mimic bladder cancer on cystoscopic examination as well as in its clinical presentation of painless gross hematuria. This report describes a 49-year-old male with repeated painless gross hematuria, who underwent transurethral resection of a suspected bladder tumor. Pathologic examination revealed papillary urothelial hyperplasia with vascular ectasia and no signs of malignancy. Massive gross hematuria occurred 2.5 years later. Cystoscopy showed multiple papillary lesions with yellowish-brown submucosal plaques on the posterior bladder wall. A second transurethral tumor resection was performed and histologic examination revealed plasma cell infiltration and eosinophilic amorphous deposits in the subepithelial stroma and vascular wall. The deposits were positive for Congo red and apple-green birefringence under polarized light examination but negative for Masson's trichrome stain, indicating that they were not fibrotic in nature. Hence, the diagnosis of amyloidosis of the urinary bladder was confirmed. Screening for amyloidosis was negative in other organ systems and the patient has remained disease-free up to the last follow-up 4 years after the second transurethral resection. Amyloidosis should be considered in the differential diagnosis of patients with recurrent hematuria who have symptoms characteristic of bladder cancer but negative pathologic study for malignancy. Correct diagnosis relies on clinical alertness and the use of a special staining technique during pathologic examination.  相似文献   
43.
目的了解初级护士资格考试通过情况。方法采用历史性研究方法,对我校近3年参加护士资格考试的188名学生考试情况进行调查。结果护士资格考试通过率低,其中基础知识通过率在4个科目中最低。结论有必要对参加考试的考生进一步强化基础知识的训练,从而提高护士资格考试的过线率。  相似文献   
44.
45.
T lymphocytes play a fundamental role in the initiation and regulation of chronic inflammatory responses in patients with asthma. CD69 is an early marker of T‐cell activation. The levels of intercellular adhesion molecule‐1 (ICAM‐1, CD54) and L ‐selectin have been reported to increase in patients with allergic diseases and asthma. The present study was therefore undertaken to investigate the expression of CD69, CD54, and L ‐selectin by T lymphocytes of children with asthma, before and after immunotherapy. Eighteen children newly diagnosed with asthma, 11 good and nine poor responders to immunotherapy, and 16 normal subjects, were enrolled in this study. The percentages of CD69+, CD54+, and CD62L+ cells in T lymphocytes were measured by using flow cytometry. The levels of CD69, CD54, and CD62L in serum and culture supernatants were determined by using enzyme‐linked immunosorbent assay (ELISA). The expression of CD69 and CD54 on CD3+ T lymphocytes was significantly higher in children with asthma than in control patients. All the patient groups expressed (spontaneously and following stimulation with phorbol myristate acetate and ionomycin together with mite‐extract proteins) greater amounts of CD69 and CD54 than did control subjects. With long‐term immunotherapy, the percentages of CD69+ and CD54+ T lymphocytes were significantly lower in patients with a good response to immunotherapy. Our results also showed significantly lower serum L ‐selectin levels following immunotherapy. In conclusion, successful immunotherapy resulted in decreased expression and production of CD69 and CD54. These results may explain, in part, the clinical efficacy of immunotherapy.  相似文献   
46.
The effects of an externally applied direct-current electric field on the movement of cultured rabbit corneal epithelial cells and stromal fibroblasts were studied. After a latency of approximately 20 minutes in an electric field, both epithelial cells and stromal fibroblasts became spindle shaped and underwent galvanotropism by aligning their long axes perpendicular to the applied electric field. The electric field stimulus thresholds for galvanotropic movements in epithelial cells and stromal fibroblasts were 4V/cm and 6 V/cm, respectively. After an additional latency of 30 minutes, both cell types manifested galvanotaxic movements: epithelial cells commenced migration in the cathodal (downfield) direction and stromal fibroblasts in the anodal (upfield) direction. For both types of cells, ruffled membranes and lamellipodia were abundant at the leading edges of migrating cells and cell processes underwent retraction at the trailing edges. At field strengths of above 10 V/cm, evidence of cellular damage (manifested by cellular rounding and detachment), attributable to the electric field treatment, was observed after 4 hours. These preliminary results suggest that galvanotaxic responses could be exploited clinically in the enhancement of corneal wound healing.  相似文献   
47.
48.
小切口胆囊切除术108例临床观察   总被引:1,自引:0,他引:1  
本文报告腹部切口5-8cm的小切口胆囊切除术108例,与同期大切口胆囊切除术相比,具有创伤较小、恢复较快、并发症少、切口疤痕小的优点,虽不如腹腔镜胆囊切除术(LC)的疼痛轻、恢复快,但并症比LC少,只要适应症选择得当,在术者的经验和技术较成熟的情况下,不昔为一种可供选择的方法。  相似文献   
49.
50.
本文报告了1990年5月以来脑干区大型、复杂占位病变15例.其中,位于脑干内3例,脚间窝2例,岩尖部4例,全岩骨区1例,全斜坡区2例,第四脑室内3例.本组采用以扩大了的岩骨入路为主的联合入路,行肿瘤全切除8例,次全切除5例.2例仅作了活检加减压术.除1例死亡外,均恢复良好.本文结合文献,对脑干区手术入路进行了讨论.  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