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   55797篇
  免费   4890篇
  国内免费   3284篇
耳鼻咽喉   538篇
儿科学   536篇
妇产科学   648篇
基础医学   7147篇
口腔科学   1094篇
临床医学   6900篇
内科学   8717篇
皮肤病学   756篇
神经病学   2993篇
特种医学   2485篇
外国民族医学   37篇
外科学   6155篇
综合类   7838篇
现状与发展   9篇
一般理论   2篇
预防医学   3461篇
眼科学   1561篇
药学   5555篇
  44篇
中国医学   2731篇
肿瘤学   4764篇
  2024年   150篇
  2023年   799篇
  2022年   2182篇
  2021年   2914篇
  2020年   1948篇
  2019年   1828篇
  2018年   1960篇
  2017年   1673篇
  2016年   1790篇
  2015年   2596篇
  2014年   3228篇
  2013年   2912篇
  2012年   4644篇
  2011年   4743篇
  2010年   3009篇
  2009年   2460篇
  2008年   3197篇
  2007年   3073篇
  2006年   2848篇
  2005年   2594篇
  2004年   1865篇
  2003年   1716篇
  2002年   1513篇
  2001年   1209篇
  2000年   1237篇
  1999年   1164篇
  1998年   655篇
  1997年   693篇
  1996年   547篇
  1995年   457篇
  1994年   370篇
  1993年   256篇
  1992年   335篇
  1991年   250篇
  1990年   216篇
  1989年   189篇
  1988年   149篇
  1987年   136篇
  1986年   106篇
  1985年   90篇
  1984年   51篇
  1983年   50篇
  1982年   22篇
  1981年   24篇
  1980年   13篇
  1979年   23篇
  1978年   11篇
  1973年   11篇
  1971年   9篇
  1969年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
目的 总结可吸收内固定材料自身增强聚丙交脂(SR-PLLA)的临床应用体会。方法 采用波兰进口SR-PLLA螺钉、棒、线治疗四肢松质骨骨折22例,随访摄片观察骨折愈合情况,检查关节活动功能。结果 术后有两侧出现并发症,一例局部少量积液,经2次穿刺抽液加压包扎痊愈;一例患者过早去除石膏功能锻炼,螺钉松动滑出,经手术复位石膏外固定治愈,无感染或过敏等情况发生。结论 掌握可吸收材料的生物力学特点,并选择适当的病例,可以最大限度地发挥可吸收内固定材料的优势。  相似文献   
102.
We have previously isolated a drug-resistant, [PC3(R)], variant of human prostate PC3 cell line, which showed significant resistance (>10-fold) to adriamycin. No known mechanisms of drug resistance were found; however, resistant cells expressed more bcl2, c-myc, and ms oncogenes compared to the sensitive cells. In this study, we found that buthionine sulfoximine (BSO), an inhibitor of gamma-glutamyl-cysteine synthetase, decreased glutathione levels by 80-90% in both cell lines. BSO treatment down-modulated Ras protein only in PC3(R) cells and caused a 4-fold sensitization of PC3(R) cells to adriamycin without affecting PC3(W) cells. Farnesol treatment also inhibited expression of Ras protein and concomitantly reversed adriamycin resistance in PC3(R) cells, indicating that altered levels of ras expression plays an important role in drug resistance in PC3(R) cells.  相似文献   
103.
A 23-year-old male involved in a high-speed collision acquired, among other injuries, a wide fracture distraction at C2/C3. Reduction was delayed by an enlarging vertebral artery pseudo-aneurysm at the site of injury which was successfully treated by proximal endovascular occlusion with a detachable polymer-filled balloon. A traumatic arachnoid cyst or pseudomeningocele was also demonstrated at the injury site but intervention was not required. The treatment and outcome of these three uncommon injuries in the literature is reviewed and discussed. Given the severity of the injury, the absence of severe long-term neurological disability is notable.  相似文献   
104.
105.
Chung KM  Kim YH  Song DK  Huh SO  Suh HW 《Neuropeptides》1999,33(6):534-541
Our previous studies have demonstrated that supraspinal GABAergic receptors are differentially involved in the antinociception induced by morphine and beta-endorphin given intracerebroventricularly (i.c.v.) in the tail-flick and hot-plate tests. These two models employed a phasic, thermal nociceptive stimulus. The present study was designed to examine the possible involvement of supraspinal GABAergic receptors in opioid-induced antinociception in the formalin test. Morphine (1 microg) and beta-endorphin (1 microg) given i.c.v. displayed the almost complete inhibitory effects against the hyperalgesic response in both phases. Muscimol (75-100 ng) and baclofen (5-10 ng) injected i.c.v. produced the hypoalgesic response in the both phases. The hypoalgesic response induced by muscimol and baclofen observed during the second phase was more pronounced than that observed during the second phase. Baclofen (2.5 ng), at the dose which did not affect the hyperalgesic response, resulted in a significant reversal of the i.c.v. administered beta-endorphin-induced hypoalgesic response observed during the second, but not the first, phase. However, the hypoalgesic response induced by i.c.v. administered morphine was not changed by the same dose of muscimol or baclofen injected i.c.v. Our results indicate that, at the supraspinal level, GABA(B)receptors appear to be involved in the modulation of antinociception induced by supraspinally administered beta-endorphin, but not morphine, in the formalin test model.  相似文献   
106.
We investigated the association between schizophrenic psychosis and an intronic polymorphism of the presenilin-1 (PS1) gene in a Chinese population. Schizophrenic and control groups had similar PS1 genotype distributions and allele frequencies, indicating that this polymorphism may not be involved in the development of schizophrenia.  相似文献   
107.
108.
We implanted bone harvest chambers (BHCs) bilaterally in ten mature male New Zealand white rabbits. Polyethylene particles (0.3+/-0.1 microm in diameter, 6.4 x 10(12) particles/ml) were implanted for two, four or six weeks bilaterally in the BHCs, with subsequent removal of the ingrown tissue after each treatment. In addition to the particles, one side also received 1.5 microg of recombinant transforming growth factor beta1 (TGFbeta1). At two weeks, the bone area as a percentage of total area was less in chambers containing TGFbeta compared with those with particles alone (7.8+/-1.3% v 16.9+/-2.7% respectively; 95% confidence interval (CI) for difference -14.0 to -4.30; p = 0.002). At four weeks, the percentage area of bone was greater in chambers containing TGFbeta compared with those with particles alone (31.2+/-3.4% v 22.5+/-2.0% respectively; 95% CI for difference 1.0 to 16.4; p = 0.03). There were no statistical differences at six weeks, despite a higher mean value with TGFbeta treatment (38.2+/-3.9% v 28.8 +/-3.5%; 95% CI for difference -4.6 to 23.3; p = 0.16). The number of vitronectin-receptor-positive cells (osteoclast-like cells) was greater in the treatment group with TGFbeta compared with that with particles alone; most of these positive cells were located in the interstitium, rather than adjacent to bone. TGFbeta1 is a pleotropic growth factor which can modulate cellular events in the musculoskeletal system in a time- and concentration-dependent manner. Our data suggest that there is an early window at between two and six weeks, in which TGFbeta may favourably affect bone ingrowth in the BHC model. Exogenous growth factors such as TGFbeta may be a useful adjunct in obtaining osseointegration and bone ingrowth, especially in revisions when there is compromised bone stock and residual particulate debris.  相似文献   
109.
家族性腺瘤性息肉病的诊断与治疗   总被引:1,自引:0,他引:1  
Li Y  Song S  Jiang Y 《中华外科杂志》1999,37(6):328-330
目的 总结家族性腺瘤性息肉病(FAP)的诊断和治疗经验。方法 回顾性分析13例FAP的临床病理资料。结果 本组13例患者,男5例,女8例,平均年龄31.5岁。其中良性5例,平均年龄25岁;癌变8例,平均年龄36岁。8例有家族史者源于6个家系,3代中共发现19例患者其中4个家系中有7例2死于大肠癌。本组患者病史2-20年,每例息肉数均超过100个。最多达3-9个/cm^2。全部病例均施行了全结肠切除  相似文献   
110.
急性非淋巴细胞白血病中MGMT与p53基因突变的研究   总被引:1,自引:0,他引:1  
目的 探讨肿瘤抑制基因p53、MGMT在急性非淋巴细胞白血病(ANLL)中的改变。方法 用聚合酶链反应-单链构象多态性(PCR-SSCP)技术对31例ANLL患者、22例正常人p53基因第5、6、7、8外显子和MGMT基因第1、4外显子进行突变分析。结果 31例ANLL中5例存在p53基因突变、4例存在MGMT基因突变,其中2例p53与MGMT同时发生突变。结论 p53基因突变在白血病发生中起一定  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