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   20243篇
  免费   1149篇
  国内免费   261篇
耳鼻咽喉   134篇
儿科学   1169篇
妇产科学   295篇
基础医学   2460篇
口腔科学   349篇
临床医学   1243篇
内科学   3472篇
皮肤病学   398篇
神经病学   1300篇
特种医学   697篇
外国民族医学   5篇
外科学   2773篇
综合类   813篇
一般理论   1篇
预防医学   1412篇
眼科学   1072篇
药学   2071篇
  5篇
中国医学   307篇
肿瘤学   1677篇
  2023年   107篇
  2022年   269篇
  2021年   409篇
  2020年   276篇
  2019年   302篇
  2018年   365篇
  2017年   294篇
  2016年   363篇
  2015年   410篇
  2014年   588篇
  2013年   773篇
  2012年   1110篇
  2011年   1130篇
  2010年   667篇
  2009年   541篇
  2008年   931篇
  2007年   970篇
  2006年   887篇
  2005年   865篇
  2004年   755篇
  2003年   757篇
  2002年   708篇
  2001年   622篇
  2000年   640篇
  1999年   571篇
  1998年   245篇
  1997年   227篇
  1996年   201篇
  1995年   183篇
  1994年   147篇
  1993年   156篇
  1992年   368篇
  1991年   392篇
  1990年   350篇
  1989年   398篇
  1988年   293篇
  1987年   307篇
  1986年   244篇
  1985年   268篇
  1984年   231篇
  1983年   206篇
  1982年   128篇
  1981年   115篇
  1979年   187篇
  1978年   123篇
  1975年   134篇
  1974年   143篇
  1973年   136篇
  1972年   123篇
  1971年   142篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
Gastrointestinal manifestations of dengue fever are mainly in the form of bleeding or liver function abnormalities. Dengue fever presenting as acute colitis-like picture is not reported to date. We report a 50-year-old man with dengue fever presenting with lower gastrointestinal bleeding and colonoscopic features of acute inflammatory colitis.  相似文献   
43.
Nine pedunculated benign synoviomata causing mechanical symptoms similar to those of a torn meniscus are described. The average age of the patients was 34.4 years. During the period of study, 2254 meniscal lesions causing mechanical symptoms were identified, giving an incidence of one benign synovioma for every 250 meniscal lesions. All the lesions were removed arthroscopically with relief of symptoms.  相似文献   
44.
Bone cells derived from human trabecular explants display osteoblastic features. We examined the modulation of alkaline phosphatase activity and cAMP production as the result of exposing trabecular explants to physiologic concentrations of dexamethasone for 4 weeks during cellular outgrowth and subculture. Cells treated with dexamethasone were observed to grow generally more slowly than control cells. Cells appeared larger and more polygonal, and staining for alkaline phosphatase was more intense in the dexamethasone-exposed cultures. There was a progressive increase in cellular PTH responsiveness with increasing duration of exposure of cells to dexamethasone. Cells grown for 6 weeks in 3 x 10(-8) M dexamethasone had a 10-fold increase in PTH-stimulated cyclic AMP accumulation. Dexamethasone-treated cells also had a significantly increased alkaline phosphatase activity. 1,25-(OH)2D3-stimulated alkaline phosphatase activity was increased approximately 20-fold. cAMP responses were significantly increased to PTH (21.7-fold), PGE1 (2.67-fold), and forskolin (4.81-fold), but not to cholera toxin. Dexamethasone-treated cells also had a mean decrease in 1,25-(OH)2D3-stimulated osteocalcin production to 26.2% of control values (p less than 0.001). Hydrocortisone treatment gave rise to similar effects but of smaller magnitude than those of dexamethasone. Testosterone did not have a significant effect on alkaline phosphatase activity or cAMP production. Skin fibroblasts showed a significant enhancement of alkaline phosphatase activity in response to dexamethasone, but of a much smaller magnitude than in bone cells. The phenotypic changes induced by long-term culture in dexamethasone are consistent with the promotion of a more differentiated osteoblastic phenotype.  相似文献   
45.
We report two full-term infants who developed repetitive focal seizures within the first 48 hours of life. Neither infant had predisposing factors and there were no abnormalities on a computed tomography (CT) scan performed on day 2 of life. Magnetic resonance imaging (MRI) performed during the second week of life showed a focal hemorrhagic infarction in both patients. We conclude that either an MRI or a contrast-enhanced CT scan should be obtained within 1 week in patients in whom the initial imaging technique failed to reveal a focal lesion, at which time a cerebral infarction can be diagnosed with greater sensitivity.  相似文献   
46.
MR appearance of two patients with large, orbital conjunctival epithelium-lined inclusion cysts are presented. Both were complications of ophthalmic surgical procedures that necessitated conjunctival incision.  相似文献   
47.
48.
Chiari I malformation (CM) associated with a cervico-thoracic syrinx due to supracerebellar arachnoid cyst has not been reported in the literature. We report such a case, managed by fenestration of the arachnoid cyst and foramen magnum decompression (FMD), aiming to reduce the inferiorly directed pressure on the cerebellum and eliminate the craniospinal pressure dissociation respectively. Imaging done post-operatively showed upward displacement of the cerebellar tonsils with a decompressed craniovertebral junction and disappearance of the syrinx.  相似文献   
49.
BACKGROUND: Twenty subjects were treated with either polidocanol (POL) or sodium tetradecyl sulfate (STS) to compare the efficacy and adverse sequelae of each agent. OBJECTIVE: To determine the safety and efficacy of two widely used sclerosing agents. METHODS: After the exclusion of saphenofemoral junction incompetency, each subject's leg veins were categorized by size (< 1, 1-3, and 3-6 mm in diameter). Each leg was then randomized to be treated with 0.5%, 1%, or 1% foam of POL or 0.25%, 0.5%, or 0.5% foam of STS according to vein size. An independent panel of four physicians, blinded to treatment, performed randomized photographic evaluations obtained pretreatment and 12 weeks post-treatment. Subject satisfaction index and overall clinical improvement assessment were also obtained. RESULTS: An average 83% improvement was noted for all vein sizes in all subjects with both POL and STS after a single treatment. Subjects were satisfied with treatment, regardless of the sclerosing agent used or the vein size treated. There was no statistically significant difference in adverse effects between each group. CONCLUSION: Both POL and STS are safe and effective sclerosing agents in the treatment of varicose and telangiectatic leg veins. Both are very tolerable and demonstrate similar post-treatment sequelae.  相似文献   
50.
We present an adenoid cystic carcinoma of the base of tongue in a 48-year-old male with a restricted chromosomal alteration by cytogenetic and spectral karyotypic analysis (SKY). SKY and G-banding analyses identified the t(6;14)(q25;q13) as the sole structural aberration in all metaphases analyzed. This finding supports a critical role for this event in the development of this tumor. The implications of chromosome 6q translocation in this case and in previously reported adenoid cystic carcinomas are highlighted and discussed.  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