全文获取类型
收费全文 | 61232篇 |
免费 | 5763篇 |
国内免费 | 4231篇 |
专业分类
耳鼻咽喉 | 699篇 |
儿科学 | 616篇 |
妇产科学 | 637篇 |
基础医学 | 6216篇 |
口腔科学 | 922篇 |
临床医学 | 7884篇 |
内科学 | 8225篇 |
皮肤病学 | 603篇 |
神经病学 | 2833篇 |
特种医学 | 2391篇 |
外国民族医学 | 39篇 |
外科学 | 6545篇 |
综合类 | 11389篇 |
现状与发展 | 17篇 |
一般理论 | 5篇 |
预防医学 | 4331篇 |
眼科学 | 1660篇 |
药学 | 6661篇 |
63篇 | |
中国医学 | 4381篇 |
肿瘤学 | 5109篇 |
出版年
2024年 | 290篇 |
2023年 | 926篇 |
2022年 | 2485篇 |
2021年 | 3207篇 |
2020年 | 2593篇 |
2019年 | 1989篇 |
2018年 | 2108篇 |
2017年 | 2112篇 |
2016年 | 1868篇 |
2015年 | 3021篇 |
2014年 | 3781篇 |
2013年 | 3471篇 |
2012年 | 5012篇 |
2011年 | 5359篇 |
2010年 | 3741篇 |
2009年 | 3008篇 |
2008年 | 3516篇 |
2007年 | 3253篇 |
2006年 | 3153篇 |
2005年 | 2899篇 |
2004年 | 1887篇 |
2003年 | 1802篇 |
2002年 | 1502篇 |
2001年 | 1242篇 |
2000年 | 1154篇 |
1999年 | 1102篇 |
1998年 | 688篇 |
1997年 | 611篇 |
1996年 | 502篇 |
1995年 | 477篇 |
1994年 | 359篇 |
1993年 | 271篇 |
1992年 | 321篇 |
1991年 | 315篇 |
1990年 | 212篇 |
1989年 | 163篇 |
1988年 | 184篇 |
1987年 | 156篇 |
1986年 | 105篇 |
1985年 | 80篇 |
1984年 | 60篇 |
1983年 | 32篇 |
1982年 | 29篇 |
1981年 | 31篇 |
1980年 | 23篇 |
1979年 | 38篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1975年 | 11篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
肉毒碱治疗TPN大鼠肝脂肪变性的研究 总被引:4,自引:1,他引:3
目的 探讨在全胃肠外营养(TPN)中补充肉毒碱减轻肝脂肪变性的作用。方法 18只正常Wistar大鼠和19只肝硬化Wistar大鼠分别随机分为6组,A1组、A2组,自由进食和进水(各6只);B1组、B2组,TPN(分别6只、7只);C1组、 ,TPN加肉毒碱(各6只)。各组实验结束后测肝功能,肝脂肪及行肝脏的组织学检查。结果 TPN组肝内脂肪显著2,TPN+肉毒碱组肝内脂肪明显减少。结论 在TPN 相似文献
102.
目的:了解血液透析病人透析过程中红细胞免疫功能指标的动态改变及不同生物相容性的透析膜对其变化的影响。方法:分别采用铜仿膜(Cu膜)、聚砜膜(PS膜)、聚甲基丙烯酸甲酯膜(PMMA膜),观察了透析过程中不同时相的红细胞免疫功能指标RBC-C3b和RBC-IC的变化。结果:尿毒症病人的 RBC-C3b显著下降, RBC-IC显著增高。透析开始后,早期 RBC-C3b进一步下降,其后逐渐上升;而 RBC-IC早期逐渐增加,其后逐渐稳定。结论:Cu膜能明显地影响红细胞的免疫功能; Ps膜次之; PMMA膜对其影响最小。 相似文献
103.
Ng HP May K Bauman JG Ghannam A Islam I Liang M Horuk R Hesselgesser J Snider RM Perez HD Morrissey MM 《Journal of medicinal chemistry》1999,42(22):4680-4694
Ligands for the CCR1 receptor (MIP-1alpha and RANTES) have been implicated in a number of chronic inflammatory diseases, most notably multiple sclerosis and rheumatoid arthritis. Because these ligands share a common receptor, CCR1, we sought to discover antagonists for this receptor as an approach to treating these disorders. A novel series of 4-hydroxypiperidines has been discovered by high throughput screening (HTS) which potently inhibits the binding of MIP-1alpha and RANTES to the recombinant human CCR1 chemokine receptor. The structure-activity relationships of various segments of this template are described as the initial HTS lead 1 was optimized synthetically to the highly potent receptor antagonist 6s. This compound has been shown to have at least 200-fold selectivity for inhibition of CCR1 over other human 7-TM receptors, including other chemokine receptors. In addition, data obtained from in vitro functional assays demonstrate the functional antagonism of compound 6s and structurally related analogues against the CCR1 receptor in a concentration dependent manner. The discovery and optimization of potent and selective CCR1 receptor antagonists represented by compound 6s potentially represent a novel approach to the treatment of chronic inflammatory diseases. 相似文献
104.
Dam rats were given lead (0, 0.58, 1.76, and 5.27 mmol/l) containing water ad lib from day 16 of gestation to weaning of the offspring on day 21 postpartum. The pups continued drinking the same lead containing water until the postnatal day 30. At the 30th day postpartum, the pups in each lead treated group were divided into four groups. The first group contains six male pups (PN30M). The second, third, and fourth groups contain six female pups (PN30F, PN60a, PN60b), respectively. The six female pups from control group formed the fifth group (PN60c). PN60a continued drinking the same lead-containing water until the postnatal day 60. PN60b were dosed with distilled water instead of lead-containing water from the 30th day to the 60th day postpartum. PN60c began to expose to 5.27 mmol Pb/l from the 30th day to the 60th day postpartum. The rats in PN30M and PN30F were decapitated on the 30th day postartum, whereas PN60a, PN60b, and PN60c were decapitated on the 60th day postpartum. The contents of metabolites of monoamine neurotransmitters: homovanillic acid (HVA), dihydroxyphenylacetic acid (DOPAC), 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyin-doleacetic acid (5-HIAA) in striatum were determined using high performance liquid chromatography with electrochemical detection (HPLC-ECD). There were significant increases in the concentrations of HVA (1.58 ± 0.30 vs. 1.17 ± 0.12 ng/mg wet tissue in the 5.27 mmol Pb/l group of PN30M, p < 0.01; and 1.44 ± 0.08 vs. 1.17 ± 0.10 ng/mg wet tissue in the 5.27 mmol Pb/l group of PN60a, p < 0.05) and DOPAC (2.39 ± 0.25, 2.47 ± 0.28, 2.39 ± 0.44 vs. 1.82 ± 0.24 ng/mg wet tissue in three lead treated groups of PN60a, p < 0.05). The significant decreases in the concentration of MHPG (37.33 ± 5.53, 32.02 ± 6.87, 33.31 ± 2.41 vs. 43.85 ± 4.93 ng/mg wet tissue in the 0.58 mmol Pb/l group of PN60a, p < 0.05; in the 1.76 and the 5.27 mmol Pb/l group of PN60a, p < 0.01) and 5-HIAA (0.23 ± 0.04 vs. 0.38 ± 0.05 ng/mg wet tissue in the 5.27 mmol Pb/l group of PN30M, p < 0.05; 0.26 ± 0.09 vs. 0.45 ± 0.09 ng/mg wet tissue in the 5.27 mmol Pb/l group of PN30F, p < 0.05; 0.31 ± 0.08 vs. 0.44 ± 0.08 ng/mg wet tissue in the 5.27 mmol Pb/l group of PN60a, p < 0.05) were observed. No significant changes in the concentration of monoamine metabolites were observed either in rats of PN60b or PN60c. The results demonstrated the disturbances of monoamine metabolism in the striatum of developmental lead exposed rats. 相似文献
105.
E. Y. Liang W. W. M. Lam J. K. S. Woo C. A. van Hasselt C. Metreweli 《European radiology》1996,6(4):553-556
In order to study the features of sinonasal polyposis (SNP) on CT, 100 consecutive coronasal sinus CT examinations done for chronic inflamamtory sinonasal disease were reviewed. The CT findings of the 27 fully documented SNPs were analyzed. All our SNPs were bilateral. There was a strong tendency for extensive involvement. Nasal polyps were seen in 22 of 27 (81%); bony trabecular deossification in 23 of 27 (85%); widening of infundibulum in 26 of 27(96%). We discovered a new sign truncation of the bony middle turbinate, where the bulbous part of bony middle turbinate was missing, in 51 of 26 (58 %) of SNP patients without a previous history of middle turbinectomy, 12 of 15(80%) were bilateral. The one SNP patient (1 of 27) with previous middle turbinectomy was not regarded to be real truncation. Truncation of the bony middle turbinate is a characteristic and easily recognizable ancillary sign, and is not seen in other patterns of sinusitis. Together with other features on coronal sinus CT, this adds diagnostic confidence in diagnosing sinonasal polyposis.
Correspondence to: E. Y. Liang 相似文献
106.
We studied jaws relation of 8 edentulous patients after complete denture restoration by using Digital Sirognathograph (D-SGG).The results indicated that the maximum intercuspation occlusion (i.e.CO or MCP) is not commonly coincident with the CRO,and the discrepancy is statistically significant.The CO is anterior to the CRO by 0.72+/-0.39mm,and it may vary significantly in different closures of the same patient. This implies that the termination of the occlusion with neuromusculature is not strictly precise and constant,but alters in a corresponding range.So,it seems reasonable to develop a "freedom of centric" in the range of 0.72+/-0.39mm anterior to the CRO.The physiological functional occlusion,therefore,is restricted to neither of the CO nor the CRO, but is guided between the two. 相似文献
107.
108.
Marc D. Liang M.D. Krishna Narayanan M.D. Peter L. Davis M.D. J. William Futrell M.D. 《Aesthetic plastic surgery》1991,15(1):313-319
Magnetic resonance imaging (MRI) provides noninvasive images of facial and neck fat for a variety of conditions. It accurately maps the soft tissues pre- and postoperatively, enabling surgeons to precisely and objectively assess results of soft tissue facial contouring and fat transplantation. The risks of MRI are few. It has the potential to provide aesthetic surgeons with a more scientific means of comparing various techniques of fat contouring. 相似文献
109.
B S Liang 《中华预防医学杂志》1991,25(2):99-101
The ocular refraction was measured by applying 1% atropine eye-drops for 3 days in 5,458 eyes (male 2,944, female 2,514) of the pupils aged 7-17 in rural areas. The results were as follows: the majority of the pupils had hyperopia (male 84.71%, female 80.55%); the frequency of the measurements was not in normal distribution; the degree of far-sight began to recede and gradually become converted to myopias with advancing age but varying greatly between age-groups. The myopias began to appear at the age of 9 and increased rapidly at the age of 14 for girls and 15 for boys. From then on the rate of conversion continued to increase with schoolgirls more than schoolboys and, as a result, formed "the dangerous stage of myopia", the values of physiological visual refraction were shown as follows: pupils aged 7-9 + 2.00 D- + 2.50 D, aged 10-13 + 1.50 D- + 1.75 D, aged 14-17 + 1.00 D- + 1.25 D. The possibility of pathological hyperopia was greater if the pupils aged 7-9 and the value of visual refraction over +3.75 D, aged 10-13 had the value over +3.00 D and aged 14-17 had the value +2.50 D. The possibility of developing myopia was great in those pupils aged 7-9 whose value was under +1.00 D and in those aged 10-17 whose value was under +0.50 D. The deprived vision of the pupils should be routinely corrected by skiascopy. 相似文献
110.
罗通定中降解物巴马汀限量检测方法 总被引:4,自引:0,他引:4
目的:研究解决罗通定及硫酸罗通定注射液中降解物巴马汀的检测方法。方法:用薄层色谱法和紫外分光光度法限量检查样品中的巴马汀。结果:与对照品斑点大小、荧光强度比较和用吸收度限值控制均可对样品中的巴马汀进行限量检查,结果与原标准一致。结论:两方法均灵敏,专属,简便,快速。 相似文献