全文获取类型
收费全文 | 36035篇 |
免费 | 1803篇 |
国内免费 | 1203篇 |
专业分类
耳鼻咽喉 | 284篇 |
儿科学 | 650篇 |
妇产科学 | 670篇 |
基础医学 | 4793篇 |
口腔科学 | 1020篇 |
临床医学 | 3758篇 |
内科学 | 4028篇 |
皮肤病学 | 441篇 |
神经病学 | 2896篇 |
特种医学 | 786篇 |
外国民族医学 | 2篇 |
外科学 | 3060篇 |
综合类 | 6266篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 3776篇 |
眼科学 | 981篇 |
药学 | 2686篇 |
20篇 | |
中国医学 | 1346篇 |
肿瘤学 | 1575篇 |
出版年
2024年 | 43篇 |
2023年 | 439篇 |
2022年 | 1037篇 |
2021年 | 1159篇 |
2020年 | 1051篇 |
2019年 | 958篇 |
2018年 | 1005篇 |
2017年 | 913篇 |
2016年 | 1059篇 |
2015年 | 1025篇 |
2014年 | 2192篇 |
2013年 | 2432篇 |
2012年 | 1903篇 |
2011年 | 2156篇 |
2010年 | 1733篇 |
2009年 | 1684篇 |
2008年 | 1717篇 |
2007年 | 1772篇 |
2006年 | 1654篇 |
2005年 | 1479篇 |
2004年 | 1306篇 |
2003年 | 1124篇 |
2002年 | 989篇 |
2001年 | 780篇 |
2000年 | 720篇 |
1999年 | 678篇 |
1998年 | 541篇 |
1997年 | 462篇 |
1996年 | 463篇 |
1995年 | 467篇 |
1994年 | 392篇 |
1993年 | 309篇 |
1992年 | 331篇 |
1991年 | 317篇 |
1990年 | 275篇 |
1989年 | 252篇 |
1988年 | 246篇 |
1987年 | 189篇 |
1986年 | 195篇 |
1985年 | 262篇 |
1984年 | 231篇 |
1983年 | 159篇 |
1982年 | 200篇 |
1981年 | 159篇 |
1980年 | 162篇 |
1979年 | 117篇 |
1978年 | 107篇 |
1977年 | 58篇 |
1976年 | 49篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Michael J. Rutten 《Methods in Cell Science》1992,14(4):235-245
Summary The adherence, growth, and electrophysiologic properties of guinea pig gastric mucous epithelial cells were investigated using porous membrane filters. We also tested three commercially available Ussing-type chambers that were designed to be used with the various porous membrane supports. Overall, the 0.45-µm Falcon-Cyclopore porous membrane was found to be very favorable for the consistent attachment and growth of our cells. This same filter also gave good results in the detection of periodic acid Schiff-positive mucous glycoprotein and Nile red neutral lipid fluorescence in the gastric mucous cells. Our cells grew poorly on collagen-coated Costar-Snapwells and Millipore Millicell-CM porous filters. For measurement of transepithelial potential difference resistance, and short-circuit current, the Costar-Snapwell with the Costar-Snapwell Diffusion-chamber system was superior in design and operation when compared to the Costar Transwell-COL, Falcon-Cyclopore, or Anotec-Anocell porous inserts used with conventional Ussing-chambers. The gastric mucous cells grew best on ICN-Cellagen membranes, but these filters routinely detached from their plastic holder and therefore could not be used for Ussing-chamber studies. The large 24.5-mm, 0.40-µm pore size Costar-Transwell-COL and the 24.1-mm, 0.45-µm Falcon-Cyclopore membranes gave good results when used in a modified horizontal-chamber for microelectrode analysis of membrane potentials and resistances of the gastric mucous cell monolayers. 相似文献
52.
53.
急性左半结肠癌梗阻一期切除吻合治疗39例 总被引:1,自引:0,他引:1
魏云志 《天津医科大学学报》2003,9(1):106-107
目的:探讨左半结肠癌致急性肠梗阻的手术处理方法。方法:回顾分析1995-2001年间39例左半结肠癌致肠梗阻一期切除吻合术的外科临床效果。结果:全组39例病人均采用梗阻近端肠管减压灌洗,并留置盲肠造瘘管术后接负压吸引,术后均一期愈合,未出现吻合口漏。随访2例中,1例存活率58%,3年存活率16%,5年存活率8%。结论:严格掌握手术适应症和基本操作,在病情允许时,对左半结肠癌急性肠梗阻行一期切除吻合手术是可行的。 相似文献
54.
补肾活血方药对慢性再生障碍性贫血患者骨髓细胞体外影响的实验研究 总被引:3,自引:0,他引:3
目的 研究补肾活血方药对慢性再生障碍性贫血 (CAA)患者骨髓细胞体外增殖的影响 ,探讨其治疗CAA的机制。方法 采用细胞培养 ,光镜下观察补肾活血中药作用于CAA患者骨髓细胞后的形态学 ;3 H TdR掺入和液体闪烁技术方法 ,检测补肾活血中药对CAA患者骨髓细胞的增殖变化。结果 加入补肾活血中药组 ,CAA患者骨髓细胞培养第 4 8小时见细胞丛明显增多 ,72h见大量集落形成 ;3 H TdR掺入法显示 ,补肾活血中药组骨髓细胞的增殖 ,以每孔 75g L最有效。在 5 0~ 10 0g L范围内 ,与对照组比较差异有显著性 (P <0 .0 1) ;2 5g L和 12 5g L组与对照组比较差异无显著性 (P <0 .0 5 )。结论 补肾活血方药在体外有促进CAA患者骨髓细胞增殖的作用 ,为补肾活血中药治疗CAA提供了实验与理论依据 相似文献
55.
文章对组织文化调查问卷的认知部分进行了分析研究,并针对出现的问题,提出医院文化建设和管理方面的建议。 相似文献
56.
本实验对培养中的大鼠胎胰胰岛组织及其移植后的形态功能进行了观察。结果表明,大鼠胎胰经短期培养,不仅内分泌胰岛β细胞的活力保存良好,而且胰外分泌腺泡大大减少以致消失。21只糖尿病大鼠,同种移植经过7天培养的胎胰胰岛,未用免疫抑制剂,术后糖尿病缓解率76.2%。 相似文献
57.
Guidance of dopaminergic neuritic growth by immature astrocytes in organotypic cultures of rat fetal ventral mesencephalon. 总被引:3,自引:0,他引:3
Astrocytes, with their many functions in producing and controlling the environment in the brain, are of great interest when it comes to studying regeneration after injury and neurodegenerative diseases such as in grafting in Parkinson's disease. This study was performed to investigate astrocytic guidance of growth derived from dopaminergic neurons using organotypic cultures of rat fetal ventral mesencephalon. Primary cultures were studied at different time points starting from 3 days up to 28 days. Cultures were treated with either interleukin-1 beta (IL-1 beta), which has stimulating effects on astrocytic proliferation, or the astrocytic inhibitor cytosine arabinoside (Ara-C). Tyrosine hydroxylase (TH)-immunohistochemistry was used to visualize dopaminergic neurons, and antibodies against glial fibrillary acidic protein (GFAP) and S100 beta were used to label astrocytes. The results revealed that a robust TH-positive nerve fiber production was seen already at 3 days in vitro. These neurites had disappeared by 5 days. This early nerve fiber outgrowth was not guided by direct interactions with glial cells. Later, at 7 days in vitro, a second wave of TH-positive neuritic outgrowth was clearly observed. GFAP-positive astrocytic processes guided these neurites. TH-positive neurites arborized overlying S100 beta-positive astrocytes in an area distal to the GFAP-positive astrocytic processes. Treatment with IL-1 beta resulted in an increased area of TH-positive nerve fiber network. In cultures treated with Ara-C, neither astrocytes nor outgrowth of dopaminergic neurites were observed. In conclusion, this study shows that astrocytes play a major role in long-term dopaminergic outgrowth, both in axonal elongation and branching of neurites. The long-term nerve fiber growth is preceded by an early transient outgrowth of dopamine neurites. 相似文献
58.
E. W. Brien Joseph M. Mirra Steven Kessler M. Suen J. K. S. Ho W. T. Yang 《Skeletal radiology》1997,26(4):246-255
It is not uncommon for sarcomatous transformation of giant cell tumor (GCT) of bone to occur after radiation, but rarely
does malignant transformation occur spontaneously, with less than 15 cases reported up to 1995. Only four of these cases have
been documented in detail. We report two additional cases of GCT of bone spontaneously transforming or ”dedifferentiating”
into osteosarcoma without radiation therapy. The first case is absolutely unique and most interesting in that the dedifferentiation
process occurred in one of multiple GCT lung metastases 6 years after successful eradication of a primary tibial tumor. The
right lung was resected due to development of a large tumor, and at pathologic examination, demonstrated several small nodules
of conventional GCT and a much larger, 14-cm mass composed of a mixture of GCT and high-grade osteosarcoma. The second case
involved a physician, who had a large tumor in the sacrum with vague symptoms for 8 years. Open biopsy revealed conventional,
benign GCT of bone with a secondary aneurysmal bone cyst. Complete curettage 2 weeks later revealed, in addition to areas
of conventional, benign GCT a second component of very high grade osteosarcoma. Both patients died less than 1.5 years from
diagnosis. This report of osteosarcomatous transformation of a conventional GCT of bone strengthens the theory that there
is a mesenchymal cell line in GCT that may spontaneously tansform to sarcoma. 相似文献
59.
同型半胱氨酸对胚胎海马神经元细胞的影响 总被引:1,自引:1,他引:0
目的 观察同型半胱氨酸(homocysteine,HCY)对海马神经元细胞分化和增殖的作用机理。方法 采用大鼠胚胎海马神经元细胞进行体外培养。观察不同浓度的HCY(0.01、0.1、1.0、10.0、100.0)mmol/L对细胞分化和增殖的影响。结果 随着剂量的增加.同型半胱氨酸对胚胎海马神经元细胞分化和增殖具有抑制作用,并用流式细胞术分析证明对脂质过氧化(LPO)的影响而使得神经元蛋白质含量增高。结论 同型半胱氨酸可抑制胚胎海马神经元细胞分化和增殖的影响,HCY可能在导致神经管畸形的过程起着重要作用。 相似文献
60.
Summary. We present a case of primary plasmocytoma of the left upper bronchus. Occlusion led to atelectasis of the left upper lobe
and subsequent poststenotic pneumonia. Therapy consisted of local excision of the bronchus and postoperative radiotherapy.
This type of lung-conserving therapy in a case of primary plasmocytoma has not been described before.
相似文献