全文获取类型
收费全文 | 91165篇 |
免费 | 6226篇 |
国内免费 | 4041篇 |
专业分类
耳鼻咽喉 | 357篇 |
儿科学 | 1524篇 |
妇产科学 | 877篇 |
基础医学 | 13973篇 |
口腔科学 | 1721篇 |
临床医学 | 7278篇 |
内科学 | 15329篇 |
皮肤病学 | 1121篇 |
神经病学 | 8119篇 |
特种医学 | 1472篇 |
外国民族医学 | 15篇 |
外科学 | 5029篇 |
综合类 | 14989篇 |
现状与发展 | 22篇 |
一般理论 | 1篇 |
预防医学 | 5225篇 |
眼科学 | 997篇 |
药学 | 14990篇 |
10篇 | |
中国医学 | 2841篇 |
肿瘤学 | 5542篇 |
出版年
2024年 | 189篇 |
2023年 | 952篇 |
2022年 | 2434篇 |
2021年 | 3229篇 |
2020年 | 2580篇 |
2019年 | 2211篇 |
2018年 | 2170篇 |
2017年 | 2502篇 |
2016年 | 2833篇 |
2015年 | 3230篇 |
2014年 | 5351篇 |
2013年 | 6088篇 |
2012年 | 5696篇 |
2011年 | 6402篇 |
2010年 | 5095篇 |
2009年 | 4895篇 |
2008年 | 5061篇 |
2007年 | 4913篇 |
2006年 | 4511篇 |
2005年 | 4247篇 |
2004年 | 3498篇 |
2003年 | 3011篇 |
2002年 | 2341篇 |
2001年 | 2002篇 |
2000年 | 1754篇 |
1999年 | 1517篇 |
1998年 | 1398篇 |
1997年 | 1232篇 |
1996年 | 1063篇 |
1995年 | 890篇 |
1994年 | 889篇 |
1993年 | 738篇 |
1992年 | 675篇 |
1991年 | 650篇 |
1990年 | 562篇 |
1989年 | 451篇 |
1988年 | 455篇 |
1987年 | 414篇 |
1986年 | 366篇 |
1985年 | 480篇 |
1984年 | 433篇 |
1983年 | 290篇 |
1982年 | 365篇 |
1981年 | 290篇 |
1980年 | 270篇 |
1979年 | 190篇 |
1978年 | 159篇 |
1977年 | 131篇 |
1976年 | 101篇 |
1974年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 18 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.
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
73.
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
74.
《Nutrition reviews》1989,47(7):219-221
Periportal cells synthesize twice as much glucose from lactate than do cells from the perivenous zone. 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.
Y. TRUDELLE A. BRACK A. DELMAS S. PEDOUSSAUT P. RIVAILLE 《Chemical biology & drug design》1987,30(1):54-60
Sequential poly(Arg-Thr-Lys-Pro) consisting mainly of the repeat of tuftsin Thr-Lys-Pro-Arg was synthesized by condensing the p-nitrophenyl ester of Arg(HCI)-Thr-Lys-(2-CI-Z)-Pro in the presence of HOBt . Two haptenic sequences of the Pre-S region of hepatitis B virus antigen (10–26 and 39–55) were prepared by solid phase and coupled to polytuftsin via glutaraldehyde. The peptides, either free or coupled to polytuftsin, were administrated to mice and the antisera were assayed by ELISA . Coupling the peptides to the polypeptide significantly improved the anti-peptide antibody titer in Freund complete adjuvant or in NaCI 0.9%. Cross-reaction between antibodies induced by the peptides and the native protein was also improved. Polytuftsin alone is very poorly immunogenic. 相似文献
77.
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
78.
79.
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
80.
D2-43病毒E蛋白在酵母细胞表面的展示 总被引:2,自引:0,他引:2
目的:在酵母细胞表面展示登革2型病毒43株(D2—43)的E基因,探索利用酵母表面展示系统建立DNA改组筛选平台的可行性。方法:通过RT-PCR扩增获得D2-43的E基因,将该基因亚克隆至T载体后,再克隆至酵母表面展示载体pYDI,于酿酒酵母EBY100中利用半乳糖进行诱导表达。表达产物采用间接免疫荧光法和FACS进行检测。结果:酵母表面展示产物可与D2-43的腹水抗体特异性地结合;在半乳糖诱导后24h,展示E蛋白的酵母细胞百分数达22.07%。结论:本研究为建立基于酵母表面展示系统的DNA改组筛选平台奠定了基础。 相似文献