全文获取类型
收费全文 | 16122篇 |
免费 | 1397篇 |
国内免费 | 1278篇 |
专业分类
耳鼻咽喉 | 159篇 |
儿科学 | 188篇 |
妇产科学 | 141篇 |
基础医学 | 2148篇 |
口腔科学 | 255篇 |
临床医学 | 2122篇 |
内科学 | 2495篇 |
皮肤病学 | 118篇 |
神经病学 | 976篇 |
特种医学 | 560篇 |
外国民族医学 | 15篇 |
外科学 | 1631篇 |
综合类 | 2590篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 1131篇 |
眼科学 | 534篇 |
药学 | 1555篇 |
22篇 | |
中国医学 | 717篇 |
肿瘤学 | 1437篇 |
出版年
2024年 | 44篇 |
2023年 | 255篇 |
2022年 | 592篇 |
2021年 | 846篇 |
2020年 | 607篇 |
2019年 | 520篇 |
2018年 | 553篇 |
2017年 | 515篇 |
2016年 | 477篇 |
2015年 | 768篇 |
2014年 | 832篇 |
2013年 | 762篇 |
2012年 | 1121篇 |
2011年 | 1288篇 |
2010年 | 736篇 |
2009年 | 649篇 |
2008年 | 895篇 |
2007年 | 924篇 |
2006年 | 837篇 |
2005年 | 955篇 |
2004年 | 554篇 |
2003年 | 502篇 |
2002年 | 448篇 |
2001年 | 365篇 |
2000年 | 426篇 |
1999年 | 404篇 |
1998年 | 288篇 |
1997年 | 243篇 |
1996年 | 183篇 |
1995年 | 183篇 |
1994年 | 158篇 |
1993年 | 143篇 |
1992年 | 129篇 |
1991年 | 122篇 |
1990年 | 91篇 |
1989年 | 86篇 |
1988年 | 69篇 |
1987年 | 64篇 |
1986年 | 51篇 |
1985年 | 40篇 |
1984年 | 15篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 3篇 |
1979年 | 9篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1960年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
β-内酰胺酶抑制短肽SIPIS04-01的表达、纯化与抑制作用测定 总被引:2,自引:0,他引:2
通过酵母双杂交系统从一个随机DNA片段文库中筛选到一个编码能与β-内酰胺酶结合的短肽SIPIS04—01的DNA序列,将它克隆到pGEX-4T-1的多克隆位点中,得到重组质粒pYG205。当用适量的IPTG诱导后,携带pYG205的E.coli DH5α能表达短肽SIPIS04-01-GST融合蛋白。利用谷胱甘肽Sepharose 4B亲和层析介质分离纯化短肽SIPIS04-01-GST融合蛋白,经凝血酶切割并分离纯化后,体外试验表明短肽SIPIS04-01具有抑制β-内酰胺酶的作用。 相似文献
53.
Choi SI Jiang CZ Lim KH Kim ST Lim CH Gong GY Lim TH 《Journal of magnetic resonance imaging : JMRI》2000,11(5):476-480
The purpose of this study was to correlate the abnormal signal area on various magnetic resonance (MR) images to the infarct area on pathologic examination and to assess the myocardial viability on the basis of MR images. T2-weighted, first-pass perfusion, and delayed gadolinium-enhanced T1-weighted images were used as "one-stop examinations" in a pig model of reperfused myocardial infarction. The results of each MR image were compared with those of 2,3, 5-triphenyltetrazolium chloride (TTC) staining. The abnormal signal areas on T2-weighted and Gd-enhanced T1-weighted images were larger than the infarct areas on TTC staining (34.7% and 32.3% vs. 28.3%; P< 0.05), whereas the nonperfused areas on perfusion images were correlated (25.6% vs, 28.3%; P = 0.139). Electron microscopic examination showed severely distorted ultrastructures in the infarct areas and mildly damaged ultrastructures in the peri-infarct areas. Perfusion images probably reflected the infarct areas, whereas T2-weighted and Gd-enhanced T1-weighted images seemed to include peri-infarct as well as infarct areas. 相似文献
54.
55.
56.
57.
Ping-xian Wang Ming-qi Fan Gui-zhi Gong Hua-ying Xu Chi-bing Huang Gen-tu Zhang 《四川大学学报(医学版)》2006,37(1):112-4, 122
OBJECTIVE: To investigate the relation between TGF-beta1 in allograft and chronic allograft nephropathy (CAN). METHODS: The levels of urine TGF-beta1 were tested in 146 recipients whose renal function were normal from September 1, 2000 to January 31, 2001. Twenty recipients with the highest level of urine TGF-beta1 were classified in group A, while 20 other recipients with the lowest level of urine TGF-beta1 were classified in group B. In these two groups biopsies were carried out in 14 cases and 12 cases respectively, and TGF-beta1 mRNA in the biopsies was measured by RT-PCR. The levels of TGF-beta1 in the blood were also measured in the two groups. Three years later, the renal function was compared between the two groups. Biopsies were carried out in renal recipients whose creatinine is higher than normal. RESULTS: The level of TGF-beta1 in the blood showed no significant difference between the two groups; 3 years after transplantation, the loss of renal function in group A was severer than that in group B. The number levels of CAN cases in group A was larger than that in group B. The expression levels of TGF-beta1 and TGF-beta1 mRNA of the allografts were higher in group A than in group B; there were statistically significant differences between the two groups. CONCLUSION: The findings suggest that there is an association between TGF-beta1 in kidneys and CAN. The level of urine TGF-beta1 after renal transplantation may predict future renal function. 相似文献
58.
59.
Dongjun Lv Zilong Zhang Jiahui Zhang Xiaolei Zhang Leifang Liu Yue Gong Jianghong Zhao Yi Li 《RSC advances》2022,12(34):21859
Organic pigments are important in a range of fields, from printing ink to industrial coatings. Azo pigments are some of the most common pigments in use today, but they typically have poor solvent solubility and tend to agglomerate. Consequently, the size and crystal structure of the pigment particles has a crucial effect on their optical and physical properties, such as color strength and solvent resistance, respectively. Several technologies, such as microreactors, have been developed to control pigment particle size, but an in-depth study of the effects of modification conditions on pigment properties (color, flowability, and solvent resistance) has not been reported to date. Therefore, in this paper, we report the surface modification of C.I. Pigment Red 146 particles using anionic (Igepon T) and non-ionic surfactants (Peregal O-25) and additives (DB-60 as the second diazo component and graphene oxide) on the pigment properties. In addition, we examined the effect of hydrothermal treatment at different temperatures on the same properties. The various modifications resulted in an increase in the solvent resistance, a reduction in the particle size (from 30.581 to 12.252 μm), a narrowing of the particle size distribution, and an increase in hydrophilicity. In addition, the color brightness and brilliance were significantly improved, and the maximum color strength reached 112.6%. These findings have applications for the development of pigments having enhanced color properties, solvent resistance, and processability.The color properties and solvent resistance of modified Pigment Red 146 were obviously improved by adding surfactants and graphene oxide. 相似文献
60.
Xue Gong Xinyue Zhang Dang Liu Chao Yang Rong Zhang Zhibo Xiao Wenzhi Chen Jinyun Chen 《The Journal of international medical research》2022,50(5)
ObjectiveTo evaluate the effect of different levels of physician experience on the high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and to provide a reference for the use of non-perfused volume ratio (NPVR) standards during training.MethodsThis prospective multicentre study enrolled patients with uterine fibroids. The effect of the physician’s level of experience on the outcomes under different NPVR standards and the learning curve of six centres without HIFU experience were analysed. The impact of patient demographic and clinical characteristics were also evaluated.ResultsA total of 1352 patients from 20 centres were included in the study. The median NPVRs were 92.00%, 88.10% and 92.86% in the no experience group, inexperienced group and experienced group, respectively. Posterior wall fibroids, lateral wall fibroids and fundus fibroids were inversely correlated with NPVR, while experienced physicians were positively correlated with NPVR. With NPVR ≥ 70% and NPVR ≥ 80% standards, physicians in the no experience group completed the learning curve on the 11th and 16th procedure, respectively. Physicians under a standard of an NPVR ≥ 90% did not complete the learning curve.ConclusionsNPVR ≥ 80% is a standard that is worth using for HIFU treatment of uterine fibroids. 相似文献