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   492737篇
  免费   31021篇
  国内免费   22864篇
耳鼻咽喉   4138篇
儿科学   9967篇
妇产科学   7873篇
基础医学   55565篇
口腔科学   7080篇
临床医学   57498篇
内科学   78651篇
皮肤病学   3747篇
神经病学   34099篇
特种医学   20817篇
外国民族医学   214篇
外科学   61195篇
综合类   52518篇
现状与发展   78篇
一般理论   20篇
预防医学   37007篇
眼科学   12296篇
药学   42099篇
  354篇
中国医学   18325篇
肿瘤学   43081篇
  2024年   905篇
  2023年   4637篇
  2022年   11662篇
  2021年   16729篇
  2020年   12352篇
  2019年   11053篇
  2018年   32430篇
  2017年   26721篇
  2016年   28235篇
  2015年   15453篇
  2014年   18806篇
  2013年   16286篇
  2012年   29685篇
  2011年   46179篇
  2010年   34067篇
  2009年   23490篇
  2008年   36061篇
  2007年   38263篇
  2006年   17565篇
  2005年   18880篇
  2004年   13883篇
  2003年   13956篇
  2002年   10831篇
  2001年   7730篇
  2000年   8675篇
  1999年   9152篇
  1998年   5629篇
  1997年   5662篇
  1996年   4420篇
  1995年   4023篇
  1994年   3306篇
  1993年   2154篇
  1992年   2864篇
  1991年   2497篇
  1990年   2238篇
  1989年   1933篇
  1988年   1614篇
  1987年   1341篇
  1986年   1110篇
  1985年   940篇
  1984年   544篇
  1983年   393篇
  1982年   266篇
  1981年   238篇
  1980年   227篇
  1979年   223篇
  1978年   90篇
  1977年   92篇
  1974年   121篇
  1973年   84篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
心包膜移植在结膜囊成形术中的应用   总被引:1,自引:1,他引:0  
目的:探讨保存人心包膜移植治疗结膜囊狭窄的临床效果及安全性。方法:对眼球摘除术后伴有结膜囊狭窄综合征的26例26眼,利用心包膜移植行部分结膜囊成形术,术后随访观察3~12个月,平均8个月。结果:24眼(92.31%)在术后30~60天移植的心包膜被结膜覆盖,感染1例(3.85%),结膜囊狭窄1例(3.85%)。结论:保存心包膜移植治疗结膜囊狭窄取材方便,疗效显著,操作简单。  相似文献   
992.
993.
994.
Aims and Objectives The significance of beaten copper appearance (BCA) on skull radiographs in children following surgery for isolated sagittal craniosynostosis has not been studied. This study was designed to look for any correlation between BCA and symptoms suggestive of intracranial hypertension in this group of patients. Materials and Methods Forty-eight consecutive children, who were operated for isolated sagittal synostosis from1987 to 2000 and had postoperative skull radiographs, were included. Patients were divided into: (a) BCA group (n = 20), consisting of children who had beaten copper appearance on skull radiographs at last follow up, and (b) Non-BCA group (n = 28), consisting of children who did not have this finding. Records were reviewed to look for symptoms suggestive of intracranial hypertension, such as headache, head banging, and irritability. Results Median age at surgery was 4.8 months for BCA group and 4 months for the non-BCA group. Follow up ranged from 4 to 156 months with a mean of 36.2 months. Total of 28.6% (n = 6) of the children with follow up radiographs done at ≤18 months of age had BCA. The incidence of BCA increased to 83.3% in children with skull radiographs performed after 48 months of age. In 18 (90%) children, the BCA was ‘diffuse’ with 5 (25%) children having the maximum possible score of 8. In the BCA group, 45% (n = 9) had symptoms compared to 10.7% (n = 3) in the control group (p = 0.0068). Conclusions This study suggests a significant number of children with BCA on radiographs develop symptoms suggestive of raised ICP following surgical treatment in infancy and prolonged follow up may be warranted in this group of patients.  相似文献   
995.
996.
关节镜下人工韧带重建前交叉韧带的临床初步体会   总被引:6,自引:0,他引:6  
目的探讨关节镜下应用LARS人工韧带重建前交叉韧带的可行性及近期疗效. 方法用法国产LARS人工韧带对16例前交叉韧带(anterior cruciate ligament,ACL)损伤行关节镜下ACL重建术.等距点钻胫骨、股骨骨道,将肌腱拉入骨道,韧带游离部分位于关节腔内,拉紧后2枚螺钉固定韧带,合并损伤同期处理. 结果手术时间51~86 min,平均64 min.术后无滑膜炎、韧带断裂、活动明显受限等并发症.16例均随访1.5~6个月,平均3.8月.按照IKDC评分标准:术前C级6例,D级10例;术后A级6例,B级9例, C级1例(χ2=6.264,P<0.05).Lysholm膝关节功能评分术前36~76分,(63.7±7.3)分;术后86~97分,(94.8±9.6)分(t=10.356,P<0.05). 结论关节镜下LARS人工韧带重建ACL,操作简便,可使膝关节获得即时稳定性,早期康复锻炼,最大限度的防止关节功能受限,近期疗效满意.  相似文献   
997.
放射性125I粒子组织间植入或联合放化疗治疗复发直肠癌   总被引:5,自引:1,他引:4  
目的探讨超声或CT引导下放射性125I粒子组织间植入治疗复发直肠癌的技术可行性、近期疗效和副反应.方法 15例直肠癌术后盆腔复发患者,女4例,男11例.硬膜外麻醉,2例经阴道超声引导,13例CT引导,行放射性125I粒子植入术.肿瘤匹配周边剂量为90~110 Gy,每颗粒子活度为0.50~0.70 mCi,植入33~70颗.术后24~48 h拍胸、盆腔X线片了解粒子是否发生移位.术后6例加三维适形放疗,4~6野/次,200~300 cGy/次,5次/周,总剂量为4 500~5 000 cGy,间隔4周.2例粒子治疗后加草酸铂、5-氟尿嘧啶和四氢叶酸化疗1个周期,随访3~15个月,根据CT扫描结果判断肿瘤大小. 结果术后平均7天疼痛缓解,其中12例完全缓解,2例部分缓解,1例无变化,有效率93%(14/15).9例肿瘤完全缓解,2例部分缓解,4例局部进展,局部控制率73%(11/15).2例术后6个月和12个月时死于肺转移.1例1颗粒子移位至盆壁,随访12个月无症状.无治疗相关并发症和副作用发生. 结论经超声或CT引导放射性125I粒子植入治疗复发直肠癌具有安全、微创、并发症发生率低和疗效肯定等优势,粒子治疗后应配合外放疗和全身化疗,有望进一步提高疗效.  相似文献   
998.
OBJECTIVE: To study the cellular expression of CD45RO, CD20, CD68 and proliferating cell nuclear antigen (PCNA) in nasal polyps. METHODS: Nasal polyp tissues from 50 patients were evaluated for cellular expression of CD45RO, CD20, CD68 and PCNA using immunohistochemistry SP by counting the average number in 5 chosen high-power fields, Histopathological observations were combined with HE. Analyses were performed on SPSS10.0. RESULTS: CD68+ cells were expressed more in nasal polyps dominated by eosinophils than by neutrophils(P < 0.05). There was no difference between CD45RO and CD20, but both of them had negative correlation(P = 0.05). Significant correlation was found between CD68+ cells and eosinophils or PCNA positive cells on epithelium. PCNA positive cells on epithelium had significant correlation on fibroblast (P < 0.05). CONCLUSION: Inflammatory cell infiltration (eosinophilia CD45RO, CD20, CD68) and cell proliferating in epithelium cells, glandular cell and fibroblast are strongly correlated with formation of nasal polyps. The nasal polyps are not only characteristic of eosinophilia but also by lymphocytes dominated by CD45RO and CD68 positive cells. CD68 may be stem cell of nasal polyp.  相似文献   
999.
OBJECTIVE: To investigate the clinicopathlogical significance of cyclinE, cyclinD1, P21WAF1/CIP1 and P27KIP1 expression in squamous cell carcinoma of maxillary sinus. METHODS: The expression of cyclinE, cyclinD1, P21WAF1/CIP1 and P27KIP1 was examined by the method of immunohistochemistry in inflammatory mucosa of maxillary sinus(10), inverting papilloma of maxillary sinus(20) and squamous cell carcinoma of maxillary sinus (50). RESULTS: (1) In inflammatory mucosa, inverting papilloma and squamous cell carcinoma, the positive immunostaining rates of cyclinD1 protein were 10.0%, 25.0%, 48.0% respectively (P < 0.05); cyclinE protein was 20.0%, 35.0%, 58.0% respectively (P < 0.05); P21WAF1/CIP1 protein was 80.0%, 65.0%, 40.0% respectively (P < 0.05) and P27KIP1 protein was 70.0%, 75.0%, 40.0% respectively (P < 0.05). (2) There was no significance between the clinical type, T stage and clinical stage of carcinoma of maxillary sinus and the expression of cyclinD1, cyclinE, P21WAF1/CIP1 and P27KIP1 (P > 0.05). (3) P21WAF1/CIP1 positive expression in highly, moderately and poorly differtiated carcinomas were 73.2% (11/15), 58.9% (11/19), 25.0% (4/16) respectively (P < 0.05). CONCLUSION: (1) With the development of the lesion, the positive immunostaining rate of cyclinE and cyclinD1 protein increases, while the rate of P21WAF1/CIP1 and P27KIP1 protein decreases. (2) P21WAF1/CIP1 expression is associated with tumour cell differentiation. (3) The mutual mechenism of cell cycle regulators plays an important role in the squamous cell carcinoma of maxillary sinus. The quantity and the frequency of four kinds of gene expression increase with the progression of maxillary sinus carcinogenesis.  相似文献   
1000.
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