全文获取类型
收费全文 | 5764篇 |
免费 | 485篇 |
国内免费 | 329篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 108篇 |
妇产科学 | 134篇 |
基础医学 | 668篇 |
口腔科学 | 97篇 |
临床医学 | 662篇 |
内科学 | 1078篇 |
皮肤病学 | 36篇 |
神经病学 | 245篇 |
特种医学 | 141篇 |
外国民族医学 | 2篇 |
外科学 | 593篇 |
综合类 | 926篇 |
预防医学 | 358篇 |
眼科学 | 123篇 |
药学 | 512篇 |
1篇 | |
中国医学 | 298篇 |
肿瘤学 | 525篇 |
出版年
2024年 | 18篇 |
2023年 | 58篇 |
2022年 | 189篇 |
2021年 | 229篇 |
2020年 | 179篇 |
2019年 | 198篇 |
2018年 | 175篇 |
2017年 | 160篇 |
2016年 | 170篇 |
2015年 | 283篇 |
2014年 | 338篇 |
2013年 | 282篇 |
2012年 | 451篇 |
2011年 | 436篇 |
2010年 | 311篇 |
2009年 | 245篇 |
2008年 | 291篇 |
2007年 | 335篇 |
2006年 | 322篇 |
2005年 | 319篇 |
2004年 | 186篇 |
2003年 | 189篇 |
2002年 | 183篇 |
2001年 | 153篇 |
2000年 | 133篇 |
1999年 | 146篇 |
1998年 | 72篇 |
1997年 | 84篇 |
1996年 | 46篇 |
1995年 | 42篇 |
1994年 | 53篇 |
1993年 | 27篇 |
1992年 | 37篇 |
1991年 | 35篇 |
1990年 | 28篇 |
1989年 | 26篇 |
1988年 | 40篇 |
1987年 | 27篇 |
1986年 | 17篇 |
1985年 | 16篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1975年 | 2篇 |
1970年 | 3篇 |
1964年 | 2篇 |
1962年 | 3篇 |
排序方式: 共有6578条查询结果,搜索用时 46 毫秒
1.
Bone morphogenetic protein (BMP) was isolated from the bone matrix of swine and partially purified by means of differential precipitation and molecular sieve chromatography. The molecular weight of BMP estimated by SDS-gel electrophoresis was 19,000 dalton. Bioassay by implanting two milligrams of BMP fraction into thigh muscles of mice resulted in bone formation in 100% of the experimental animals.
相似文献
2.
Jing‐Long Huang Liang‐Shiou Ou Ching‐Hsiung Tsao Li‐Chen Chen Ming‐Ling Kuo 《Pediatric allergy and immunology》2002,13(6):426-433
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
3.
外周血及移植肾内嗜酸性粒细胞变化的临床意义 总被引:2,自引:0,他引:2
为了解移植肾在急性排斥时外周血和移植肾内嗜酸性粒细胞(EO)变化的意义,动态观察31例同种异体肾脏移植病人的外周血和移植肾内EO的变化。结果发现在急性排斥反应时,移植肾内EO数>2%者占80.9%,明显高于肾功能稳定时,P<0.01;重度排斥中血EO数>4%者占82.6%,明显高于肾功能稳定时和中度以下排斥者,P<0.01。结果认为,测定移植肾内的EO变化可以做为监测急性排斥反应的可靠指标,外周血中的EO明显增多常提示排斥反应较为严重。 相似文献
4.
5.
K Shinozaki T Kawasaki J Kambayashi M Sakon E Shiba M Ou T Mori 《Methods and findings in experimental and clinical pharmacology》1992,14(9):663-665
Species differences in platelet aggregation induced by platelet-activating factor (PAF) were investigated by using the same procedure of platelet preparation and biological assay. Washed platelets of six different species (horses, dogs, rats, rabbits, sheep and guinea pigs) were prepared employing the same method and platelet aggregation was induced by C16-PAF. Horse platelets were most sensitive to PAF (8.0 x 10(-12) M) and rabbit platelets activated by 5.0 x 10(-11) M PAF were also sensitive enough to detect PAF in clinical samples. 相似文献
6.
7.
1 Introduction
Defensins are small cationic antimicrobial peptides that function in the host's innate immune system. The human defensin family includes three small peptides from the azurophil granules of polymorphonuclear cells named human neutrophil peptide (HNP)-1, HNP-2, HNP-3,which consist 5%-7% of the protein of human neutrophil. HNP-4 is approximately one hundred times less abundant. They demonstrate antibacterial, antifungal and antiviral properties in vitro. HNPs are important component of nonoxidative mechanism in macrophages, and can direct inactivate the enveloped viruses. Because only special cells express defensins. And it is hard to extract them naturally and the production is few. So researcher expect to obtain defensins highly through heterogenous expression by gene engineering technology. In order to express HNP-1, we cloned the cDNA of HNP-1 from human polymorphonuclear cells in peripheral blood, and constructed its eukaryotic expression vector, which provided a base for the further study on its mechanism of antimicrobial effect. 相似文献
8.
将15只大鼠左侧第11或12肋间神经从根部向外,自周围组织完全分离出20~35mm,并于此处剪断。再将其近端改向植入脊髓左侧半 L_(1~2) 之间的髓节内。在存活57~413天后解剖观察,发现自移植神经的干上发出1~3条新分支,分布于原去神经的肋间肌。经光、电镜观察证实是成活的再生神经纤维。于移植神经干注射 CB-HRP 后,发现这些神经纤维来源于原肋间神经髓节的前角和移植部髓节内的神经细胞。故认为外周神经缺损,不作神经对接或桥接,不经断离神经的远段,在一定条件下可以由近段发出再生纤维组成新支,分布于去神经的靶组织。 相似文献
9.
目的:研制抗人喉癌/抗血管内皮因子(VEGF)双功能克隆抗体,用于喉癌抗血管生成治疗。方法:采用二次杂交瘤技术制备抗人喉癌/抗VEGF双功能抗体。经酶联免疫吸附试验法和SP法检测喉癌及癌前病患者血清及癌组织中VEGF的含量表达。结果:获得6株分泌抗人喉癌/抗VEGF双功能抗体的杂交瘤,经免疫组化证实与喉癌细胞特异性结合率为93%,而与血管内皮细胞结合率为89%。血清中VEGF含量表达,喉癌组与癌前病组及正常对照组相比差异均显著。IgG亚型鉴定为IgG2aBSAb抗体效价为1:25 600倍(ELISA法)。结论:二次杂交瘤法制备的双功能抗体具有均匀性、可控性、效价高、稳定性好,可用于喉癌抗血管生成治疗,动态检测可作为判断喉癌预后的客观指标。 相似文献
10.
The amino-terminus of mCAT1 and homologous proteins is predicted to form a positively charged, amphipathic alpha helix on the cytoplasmic side of the plasma membrane. Peptides with similar sequence motifs often provide membrane anchors, protein-protein interaction domains, or intracellular transport-targeting signals. Deleting most of the cytoplasmic N-terminal sequence of mCAT1 led to reduced expression on the cell surface and accumulation in the endoplasmic reticulum but did not abrogate receptor function. Surprisingly, when the N-terminal 36 or 18 amino acids of mCAT1 were fused to green fluorescent protein (gfp), gfp accumulated almost exclusively in mitochondria. Mitochondrial targeting depended on arginines at positions 15 and 16 and was inhibitable by downstream transmembrane sequences. Although the full-length mCAT1 was not detected in mitochondria, the mitochondrial-targeting property of the N-terminal sequence fused to gfp is conserved in orthologous and paralogous proteins that diverged approximately 80 million years ago, suggesting a conserved biological function. We propose that the conserved N-terminal motif of CAT proteins provides a regulatable signal for transport to, or retention in, different cell membrane compartments. 相似文献