全文获取类型
收费全文 | 96062篇 |
免费 | 6533篇 |
国内免费 | 4183篇 |
专业分类
耳鼻咽喉 | 385篇 |
儿科学 | 1715篇 |
妇产科学 | 973篇 |
基础医学 | 14692篇 |
口腔科学 | 1866篇 |
临床医学 | 9248篇 |
内科学 | 16419篇 |
皮肤病学 | 1148篇 |
神经病学 | 8221篇 |
特种医学 | 1810篇 |
外国民族医学 | 16篇 |
外科学 | 6465篇 |
综合类 | 16246篇 |
现状与发展 | 23篇 |
预防医学 | 5616篇 |
眼科学 | 1011篇 |
药学 | 11952篇 |
16篇 | |
中国医学 | 3105篇 |
肿瘤学 | 5851篇 |
出版年
2024年 | 203篇 |
2023年 | 1020篇 |
2022年 | 2497篇 |
2021年 | 3480篇 |
2020年 | 2807篇 |
2019年 | 2434篇 |
2018年 | 2416篇 |
2017年 | 2688篇 |
2016年 | 3045篇 |
2015年 | 3402篇 |
2014年 | 5832篇 |
2013年 | 6617篇 |
2012年 | 6093篇 |
2011年 | 6727篇 |
2010年 | 5447篇 |
2009年 | 5331篇 |
2008年 | 5466篇 |
2007年 | 5377篇 |
2006年 | 4723篇 |
2005年 | 4448篇 |
2004年 | 3679篇 |
2003年 | 3142篇 |
2002年 | 2405篇 |
2001年 | 2087篇 |
2000年 | 1797篇 |
1999年 | 1589篇 |
1998年 | 1447篇 |
1997年 | 1281篇 |
1996年 | 1114篇 |
1995年 | 929篇 |
1994年 | 845篇 |
1993年 | 710篇 |
1992年 | 610篇 |
1991年 | 572篇 |
1990年 | 488篇 |
1989年 | 386篇 |
1988年 | 373篇 |
1987年 | 350篇 |
1986年 | 304篇 |
1985年 | 445篇 |
1984年 | 398篇 |
1983年 | 262篇 |
1982年 | 306篇 |
1981年 | 241篇 |
1980年 | 224篇 |
1979年 | 150篇 |
1978年 | 137篇 |
1977年 | 106篇 |
1976年 | 99篇 |
1975年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
The cause of Alzheimer's disease is unknown. Several factors have been proposed including head trauma. At present, the link between head injury and a subsequent neurodegenerative process is largely circumstantial, except in the case of dementia pugilistica (punch drunk syndrome) found in boxers. Recent studies have shown that the brains of boxers with this syndrome contain large numbers of 'diffuse' beta-protein immunoreactive plaques. We supposed that this plaque type might be associated with trauma induced Alzheimer-like degeneration. In order to test this hypothesis we have re-investigated a previously reported case of post-traumatic premature Alzheimer's disease. Immunocytochemistry using antibodies to amyloid beta-protein revealed large numbers of 'diffuse' non-Congophilic plaques with little or no neuritic component. A similar preponderance of this plaque type is present in the brains of boxers with dementia pugilistica. Our observations support the idea of a trauma induced Alzheimer-like degenerative process and indicate that such a condition is associated with a marked preponderance of 'diffuse' plaques. 相似文献
72.
文化休克(culture shock),又译为文化震撼或文化震惊,是指生活在某一种文化环境中的人初次进入到另一种文化环境,如到了不同的民族、社会群体中或地区甚至国家时所产生的思想混乱与心理上精神紧张综合征。新入校中专护生,由于文化环境的改变,往往会出现孤独、焦虑、无助等文化休克的种种表现,这些现象若不能及时得到解决,将不利于他们的全面健康状态的成长与发展。众所周知,WHO明确规定,健康不但是没有疾病和身体缺陷,还要有完整的生理、心理状态和良好的社会适应能力。因此,新入校中专护生这一特殊群体所产生的文化休克现象应引起学校有… 相似文献
73.
George Wolf DPhil 《Nutrition reviews》2007,65(8):385-388
Retinol-binding protein (RBP) is the transport protein that carries retinol in the circulation from the liver to its target tissues. The existence of a cell-surface receptor on the target cells, which mediates the uptake of retinol from RBP, has been known since 1975. Recently, it was identified as an integral transmem-brane protein named STRA6 that is inducible by retinoic acid in certain cancer cells. The receptor was found to be highly specific for RBP, with high affinity, and to be localized in all tissues known to require retinol for their function, particularly the pigment epithelium of the eye. 相似文献
74.
Evans A. M. Nation R. L. Sansom L. N. Bochner F. Somogyi A. A. 《European journal of clinical pharmacology》1989,36(3):283-290
Summary We have developed a novel and reproducible method for determining the plasma protein binding of the two ibuprofen enantiomers in the presence of each other. The method involves the use of radiolabelled racemic ibuprofen, equilibrium dialysis, derivatization of the enantiomers to diastereomeric amides, high-performance liquid chromatography, and radiochemical analysis.We have determined the plasma protein binding of R(–)- and S(+)-ibuprofen in 6 healthy male volunteers after the oral administration of 800 mg racemic ibuprofen.The mean time-averaged percentage unbound of the R(–)-enantiomer, 0.419 was significantly less than that of the S(+)-enantiomer, 0.643, consistent with stereoselective plasma protein binding.The percentage unbound of each ibuprofen enantiomer was concentration-dependent over the therapeutic concentration range and was influenced by the presence of its optical antipode. 相似文献
75.
Summary The histogenesis of stromal cells in capillary hemangioblastoma has been the subject of debate. The light and electron microscopic studies of hemangioblastomas presented here showed pericytic and leiomyoblastic features in stromal cells. Cells cultured by the monolayer method showed similar features to those of the original tumors. Immunohistochemical studies for glial fibrillary acidic protein and factor VIII/von Willebrand factor indicated that stromal cells were antigenically distinct from astrocytes and endothelial cells. These findings suggest that stromal cells are closely related to pericytes and smooth muscle cells, and support Rhodin's speculation that pericytes serve as a precursor to smooth muscle cells. 相似文献
76.
Jennifer L. King Rita J. Miller James P. Blue Jr. William D. O'Brien Jr. John W. Erdman Jr. 《Nutrition Research》2009
Epidemiological studies have shown dietary magnesium (Mg) intake and serum Mg levels to be inversely correlated with the development of atherosclerosis. We hypothesized that low levels of Mg would promote atherosclerotic plaque development in rabbits. New Zealand white rabbits (4 months old, n = 22) were fed an atherogenic diet containing 0.12% (−Mg), 0.27% (control), or 0.43% (+Mg) Mg for 8 weeks. Blood samples were obtained at baseline, 2, 4, 6, and 8 weeks and were assayed for total cholesterol, high-density lipoprotein (HDL), non-HDL, triglycerides (TG), C-reactive protein, serum Mg, and erythrocyte Mg. Aortas from −Mg had significantly more plaque, with an intima thickness 42% greater than control and 36% greater than +Mg. Serum cholesterol levels rose over time, and at 8 weeks, −Mg had the highest and +Mg the lowest total and non-HDL cholesterol and TG levels, although these results did not reach significance. Over time, serum Mg levels increased, and erythrocyte Mg levels decreased. C-reactive protein significantly increased in all groups at 4 and 6 weeks but returned to baseline levels by 8 weeks. This study supports the hypothesis that inadequate intake of Mg results in an increase in atherosclerotic plaque development in rabbits. 相似文献
77.
78.
玄继昌 《中国心血管病研究杂志》2007,5(6):444-446
目的观察急性冠状动脉综合征(ACS)患者血清高敏C-反应蛋白(Hs-CRP)、血脂水平变化及血脂康的干预情况。方法69例ACS患者随机分为血脂康组(40例)和常规治疗组(29例),治疗前后分别测定Hs-CRP、总胆固醇、甘油三酯、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C);另30名健康人为对照组。结果与对照组比较,ACS患者Hs-CRP水平明显升高,且与心肌损害程度密切相关。血脂康治疗2周,能明显下调ACS患者的Hs-CRP水平。结论血清Hs-CRP水平与ACS的发生、严重程度密切相关,血脂康的抗炎作用在ACS的早期治疗中有重要意义。 相似文献
79.
以小麦(Triticum aestivum L.)品种石4185为材料,研究了45 ℃处理0~120 min对小麦未成熟籽粒谷甘胱肽转移酶(GST)、谷胱甘肽还原酶(GR)、过氧化氢酶(CAT)和过氧化物酶(POD)活性, 超微弱发光,种子萌发和愈伤组织诱导的影响.结果表明,热休克处理使未成熟籽粒萌发率、愈伤组织诱导率和GST活性明显增加,且其作用随处理时间的延长而增大;在处理过程中, CAT活性先减少后增加,热休克对GR活性无明显影响.GST的活性与蛋白质质量分数呈显著正相关. 相似文献
80.
目的改善心脑血管缺氧载氧药物是一种创新药物。由于它半径比红细胞小400~1 000倍,易于通过毛细血管,给缺血组织及时供氧,迅速缓解或纠正缺氧状态,达到治疗抢救目的。血红蛋白的纯化工艺是载氧药物研制的重要工艺步骤。方法本研究建立了一套通过热敏法分离纯化人脐带血血红蛋白的工艺以及较为完善的纯化血红蛋白质量检测指标。结果与现有的纯化方式相比,热敏法操作简便,仪器设备造价低廉,纯化与病毒灭活同时进行,得到的纯化产品损失少,纯度高,各项理化指标达到国际水平。结论本工艺适用于规模制备纯化血红蛋白,为进一步研制治疗心脑血管缺氧载氧药物创造了有利条件。 相似文献