全文获取类型
收费全文 | 3877篇 |
免费 | 338篇 |
国内免费 | 206篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 92篇 |
妇产科学 | 104篇 |
基础医学 | 301篇 |
口腔科学 | 46篇 |
临床医学 | 397篇 |
内科学 | 484篇 |
皮肤病学 | 52篇 |
神经病学 | 107篇 |
特种医学 | 211篇 |
外科学 | 352篇 |
综合类 | 765篇 |
预防医学 | 333篇 |
眼科学 | 46篇 |
药学 | 441篇 |
7篇 | |
中国医学 | 421篇 |
肿瘤学 | 209篇 |
出版年
2024年 | 21篇 |
2023年 | 48篇 |
2022年 | 90篇 |
2021年 | 145篇 |
2020年 | 114篇 |
2019年 | 60篇 |
2018年 | 90篇 |
2017年 | 82篇 |
2016年 | 78篇 |
2015年 | 154篇 |
2014年 | 178篇 |
2013年 | 212篇 |
2012年 | 307篇 |
2011年 | 309篇 |
2010年 | 238篇 |
2009年 | 245篇 |
2008年 | 225篇 |
2007年 | 248篇 |
2006年 | 206篇 |
2005年 | 136篇 |
2004年 | 95篇 |
2003年 | 95篇 |
2002年 | 88篇 |
2001年 | 66篇 |
2000年 | 30篇 |
1999年 | 14篇 |
1998年 | 34篇 |
1997年 | 32篇 |
1996年 | 28篇 |
1995年 | 36篇 |
1994年 | 21篇 |
1993年 | 30篇 |
1991年 | 13篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1980年 | 7篇 |
1977年 | 7篇 |
1959年 | 49篇 |
1958年 | 103篇 |
1957年 | 107篇 |
1956年 | 79篇 |
1955年 | 82篇 |
1954年 | 67篇 |
1949年 | 10篇 |
排序方式: 共有4421条查询结果,搜索用时 15 毫秒
1.
多级图像对比度放大技术在膝关节摄影中的应用 总被引:1,自引:0,他引:1
目的:分析评价膝关节摄影中多级图像对比度放大技术(MUSICA)参数设定的成像效果,为实际临床应用提供理论指导。方法:随机抽取膝关节侧位软拷贝图像70例,以骨皮质、骨小梁、肌间隙、髌上囊、皮下脂肪为比对目标,由三位观察者对其显示情况进行分析,并对结果进行统计分析。结果:MUSICA处于较小值(0~2)时,适合于软组织显示,但图像锐利度欠缺;处于较高值时(4~6)适合于观察骨皮质、小梁等细节信息,但较多地出现伪影,共25例;处于2~4时整体影像对比度适中,如实反映人体密度结构。结论:作图像处理时应将MUSICA为2~4设定为常规,实际应用通常情况下可以选择该处理方法,但应根据具体要求适当调整MUSICA参数值。 相似文献
2.
3.
4.
5.
We report the case of a 26-year-old man affected by a symmetrical keratoderma localized to the interdigital spaces of the fingers. No occupational, traumatic, or irritant factors were discovered. Clinical and histological features were consistent with the diagnosis of symmetrical interdigital hyperkeratosis, a sporadic disorder described by Frei in 1926. We believe this condition to be less rare than the few cases reported in the literature would suggest. 相似文献
6.
7.
8.
9.
目的 探讨上皮型钙粘蛋白 (E cadherin ,E cad)在子宫内膜癌中的表达意义。方法 采用免疫组织化学方法检测 16例子宫内膜癌及 10例子宫肌瘤、卵巢囊肿患者 (对照组 )的E cad表达。结果 子宫内膜癌患者的E cad表达阳性率较对照组显著增高 (P <0 .0 5 )。子宫内膜癌E cad表达水平 :①与临床分期相关 ,临床早期表达显著高于晚期 (P <0 .0 5 ) ;②与肿瘤细胞分化程度相关 ,分化越差 ,表达越低 (P <0 .0 5 ) ;③与子宫肌层浸润深度成反比 ,浸润肌层越深表达越低 (P <0 .0 5 )。结论 E cad在子宫内膜癌的侵袭转移中发挥重要的作用 ,它的丢失是癌细胞发生侵袭性生长过程中的关键环节 相似文献
10.
Suppression of human ovarian carcinoma metastasis by the metastasis-suppressor gene, BRMS1 总被引:7,自引:0,他引:7
Metastasis-suppressor genes, by definition, suppress metastasis without affecting tumorigenicity and, hence, present attractive targets as prognostic or therapeutic markers. BRMS1 (breast cancer metastasis suppressor) has recently been identified as a metastasis-suppressor gene for human breast cancer and melanoma. Expression of BRMS1 messenger RNA (mRNA) in multitissue including normal prostate, ovarian, testis, and colon has been detected by northern blot analysis. We hypothesize that the role of BRMS1 in tumor progression may not be limited to breast cancer and melanoma. We previously found that BRMS1 mRNA levels in primary ovarian epithelial carcinomas were significantly lower than that in normal ovarian and benign tumors (P < 0.05), and statistical analysis of BRMS1 mRNA levels revealed that BRMS1 mRNA levels were significantly higher in early tumor stages (I, II) compared with advanced tumor stages (III, IV) in which lymph node or distant metastases were present (P < 0.01). Our data showed that reduced BRMS1 mRNA seems to influence ovarian carcinoma metastatic ability. Therefore, we transfected BRMS1 plasmid into highly malignant ovarian carcinoma cell line, HO-8910PM, and examined cell biologic behaviors including proliferation, adhesion, invasion, and metastasis in vitro and in vivo. BRMS1 expression did not alter the proliferation of HO-8910PM cells in vitro and primary tumor formation in vivo. But, BRMS1 expression significantly suppressed the cell adhesion to extracellular matrix components and in vitro cell invasion in BRMS1-transfected HO-8910PM cells compared to parental HO-8910PM and vector-only transfectants (HO-8910PM-vect). Furthermore, motility of BRMS1 transfectants was inhibited. lung colony formation of intravenously injected BRMS1 transfectants in nude mice was significantly reduced. Also, BRMS1 transfectants form significantly less metastatic to organs of peritoneal cavity in orthotopically implanted ovarian tumor nude models. We further discovered that BRMS1 expression did downregulate expression of an actin-bundling protein associated with cell motility -fascin, which perhaps is the mechanism underlying BRMS1 suppression of metastasis. These data suggested that in addition to its already described role in breast cancer and melanoma, BRMS1 functions as a metastasis-suppressor gene in ovarian carcinoma by modifying several metastatic-associated phenotypes, offering a new target for therapeutic intervention. 相似文献