全文获取类型
收费全文 | 153712篇 |
免费 | 12807篇 |
国内免费 | 6991篇 |
专业分类
耳鼻咽喉 | 1182篇 |
儿科学 | 4606篇 |
妇产科学 | 3296篇 |
基础医学 | 19588篇 |
口腔科学 | 5919篇 |
临床医学 | 15254篇 |
内科学 | 22737篇 |
皮肤病学 | 2437篇 |
神经病学 | 10325篇 |
特种医学 | 3954篇 |
外国民族医学 | 44篇 |
外科学 | 15014篇 |
综合类 | 23549篇 |
现状与发展 | 27篇 |
预防医学 | 11518篇 |
眼科学 | 3726篇 |
药学 | 13160篇 |
48篇 | |
中国医学 | 5269篇 |
肿瘤学 | 11857篇 |
出版年
2024年 | 418篇 |
2023年 | 1996篇 |
2022年 | 4095篇 |
2021年 | 5395篇 |
2020年 | 4920篇 |
2019年 | 4625篇 |
2018年 | 4500篇 |
2017年 | 4981篇 |
2016年 | 5275篇 |
2015年 | 5398篇 |
2014年 | 9383篇 |
2013年 | 11312篇 |
2012年 | 9083篇 |
2011年 | 10296篇 |
2010年 | 8461篇 |
2009年 | 8123篇 |
2008年 | 8447篇 |
2007年 | 8574篇 |
2006年 | 7645篇 |
2005年 | 6942篇 |
2004年 | 5874篇 |
2003年 | 5092篇 |
2002年 | 4190篇 |
2001年 | 3710篇 |
2000年 | 3093篇 |
1999年 | 2679篇 |
1998年 | 2274篇 |
1997年 | 2070篇 |
1996年 | 1874篇 |
1995年 | 1676篇 |
1994年 | 1438篇 |
1993年 | 1162篇 |
1992年 | 1077篇 |
1991年 | 908篇 |
1990年 | 845篇 |
1989年 | 676篇 |
1988年 | 555篇 |
1987年 | 494篇 |
1986年 | 422篇 |
1985年 | 610篇 |
1984年 | 486篇 |
1983年 | 338篇 |
1982年 | 444篇 |
1981年 | 342篇 |
1980年 | 297篇 |
1979年 | 208篇 |
1978年 | 177篇 |
1977年 | 142篇 |
1976年 | 154篇 |
1975年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
环氧合酶-2和血管内皮生长因子共表达与肝细胞癌血管形成的关系 总被引:7,自引:6,他引:1
目的 探讨环氧合酶 (COX) 2与肝细胞癌血管形成的关系。方法 利用免疫组织化学、Westernblot方法检测 48例肝癌组织中COX 2和血管内皮生长因子 (VEGF)蛋白及逆转录 聚合酶链反应法 (RT PCR)检测COX 2和VEGFmRNA的共表达 ,对共表达COX 2和VEGF蛋白和mRNA的肝癌组织进行微血管记数。结果 免疫组织化学检测中 ,48例肝癌组织 3 6例共表达COX 2和VEGF蛋白。类似结果见于蛋白电泳分析。RT PCR显示 ,48例肝癌组织 3 6例共表达COX 2mRNA和VEGFmRNA。两者之间的表达明显相关 (γ =0 .845 )。共表达COX 2和VEGF蛋白和mRNA的肝癌组织中 ,平均微血管数 (5 6.8± 17.5 )个 ,明显高于阴性表达组。结论 COX 2可能与肝细胞癌的血管形成有关 ,且其作用之一可能是通过上调VEGF通道来发挥的 相似文献
132.
Objective To investgate the effects of TGF β 3 on rat hepatic fibrosis. Methods The TGF β 3 cDNA was cloned into rAAV2 vector. Rats were randomly divided into four groups: normal control group, model group, negative control group and TGF β 3 group. Hepatic fibrosis was induced by hypodermic injection of 40% CCI4. Recombinant AAV2-TGF β 3 viral particles were injected via the vena caudalis one week before CCh treatment. Rats were executed 8 weeks after CCI4 treatment, global histological change was observed after HE staining, the distribution of the collagen fibers was observed after masson staining, his-tochemistry was done to observe the expression of collagen Ⅰ; The positive area rate of the collagen fibers and the average optical rate of collagen Ⅰ were quantified. Results HE staining indicated that collagen fibers were reduced in the TGF β 3 group. Masson staining shown that the collagen fibers were distributed around the blood vessel, in the portal area and disse space. Compared to the model group (13.2%±2.2%) and negative control group (12.3%±1.5%), the collagen fibers in liver tissues of TGF β3 group (7.7% ± 1.5%) were significantly decreased (q = 9.456, P < 0.01; q = 8.217, P < 0.01). Histochemistry indicated that the collagen fibers of liver tissues of TGF 15 3 group (0.185±0.033) were significantly higher than those in the model group (0.252±0.042) and the negative control group (0.230±0.029), (q = 6.228, P < 0.01; q = 4.346, P < 0.01). Conclusion TGF β 3 alleviates the damage to hepatic cell and the level offibrosis in CCI4 treated rats and inhibits the expression of collagen Ⅰ. 相似文献
133.
脱细胞尿道及其海绵体基质制备的实验研究 总被引:1,自引:0,他引:1
目的 探索脱细胞尿道及其海绵体基质的制备方法。方法取健康壮年兔完整尿道及其海绵体组织,以Triton-X100与NH3H2O联合提取法进行脱细胞处理。标本做HE染色,组织学观察分析脱细胞效果。结果脱细胞处理11天后,成功获得脱细胞及其海绵体基质,所得基质外观良好。HE染色观察无细胞存在。弹力纤维排列规整,间隙较大,结构无破坏。结论利用Triton-X100与NH3H2O联合提取法可成功制备完整无细胞尿道及其海绵体基质,为尿道再造修复提供崭新思路。 相似文献
134.
Knut A. Selvig Ulf M. E. Wikesjö Gary C. Bogle Richard D. Finkelman 《Journal of clinical periodontology》1994,21(6):380-385
Abstract. Effects of a topically applied growth factor combination on fibroblast migration, collagen fiber formation and bone regeneration were studied in standardized periodontal defects in 4 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and into the dentin of maxillary and mandibular teeth. Collagen sponges, impregnated with 200 ng insulin-like growth factor II, 20 ng basic fibroblast growth factor and 6 ng transforming growth factor beta 1 were fitted to defects randomly in right or left quadrants and the flaps repositioned and sutured. Contralateral control defects received the collagen with vehicle only. Experimental procedures were staggered to allow observations of healing 3, 7, 10, and 14 days after surgery. Histometric analysis showed no differences in fibroblast and collagen density between control and growth factor defects. Bone regeneration was significantly greater in control than in growth factor defects 10 and 14 days after surgery. The rate of healing generally appeared more affected by intra-dog variations or procedural variations than by the growth factor combination. 相似文献
135.
The morphologic effects of androgen deprivation in the different lobes of the rat prostate were examined by light microscopic morphometry. The prostates of Wistar male rats (260-340 g) were fixed in situ by glutaraldehyde perfusion in castrated animals 1 week after gonadectomy and in intact animals. The ventral (VP), dorsal (DP), and lateral (LP) lobes as well as the coagulating gland (CG) were dissected out, weighed, and processed for light microscopy. Using stereologic methods the following parameters were estimated for each lobe: volume fraction of connective tissue, epithelium and glandular lumina, average epithelial height, average epithelial cell volume, and total number of epithelial cells. Castration leads to a 58-76% reduction of the wet weight of all prostatic lobes. The decrease of glandular tissue is greater in VP than in LP, DP, and CG. In VP and LP, there is a 39-45% reduction of the epithelial height, and this effect is less pronounced in DP and CG. For all lobes, the shrinkage of average epithelial cell volume is in the same range (25-30%). Moreover, in VP and LP, there is a 70% reduction of the total number of cells, whereas the reduction is less in DP and CG. It thus seems that the reduction of prostatic epithelial tissue mass upon castration is due to a reduction of the number of cells as well as a reduction of the volume of individual cells. VP and LP appear to be more androgen-dependent than DP and CG. 相似文献
136.
Macrophage-like cells from explant cultures of rat sciatic nerve produce apolipoprotein E 总被引:3,自引:0,他引:3
Apolipoprotein E is synthesized and secreted by degenerating peripheral nerve, but the role of resident endoneurial cells in this process is not clear. To exclude the involvement of nonresident cells, we examined the cellular source of endoneurial apolipoprotein E in explant cultures of rat sciatic nerve. The cellular outgrowth from these explant cultures released apolipoprotein E into the culture medium. The cellular outgrowth contained fibroblasts, Schwann cells, and a population of cells with many phenotypic characteristics of macrophages, including the production of apolipoprotein E. No other cell type in the cultures appeared to contribute to this production. These data suggest that apolipoprotein E is produced by resident endoneurial cells in explant cultures and that these cells are macrophages. 相似文献
137.
138.
139.
MN Tabrizi† C Chams-Davatchi† N Esmaeeli† P Noormohammadpoor† F Safar† H Etemadzadeh† HA Ettehadi‡ F Gorouhi† 《Journal of the European Academy of Dermatology and Venereology》2007,21(1):79-84
BACKGROUND: Pemphigus vulgaris (PV) is a severe blistering disease involving the skin and mucous membranes. The most common causes of death in these patients are adverse effects of drugs, and infection. Skin lesions are one of the important sources of infection. Thus, any local treatment that could reduce healing time of lesions and consequently reduce the total dosage of drugs needed to treat is favourable. OBJECTIVE: To evaluate the efficacy of epidermal growth factor (EGF) in reducing healing time of lesions in patients with pemphigus vulgaris. METHODS: In this randomized, double-blind, within-patient, left/right, controlled trial, 20 hospitalized patients with pathologial and immunohistologial (direct and indirect immunoflourecence) proven pemphigus vulgaris (PV) were chosen. In addition, all patients had at least one appropriate pemphigus lesion on each side of the body that had not healed after 2-week systemic therapy and sterile saline washing. EGF (10 microg/g) in 0.1% silver sulfadiazine cream vs. 0.1% silver sulfadiazine cream alone was applied randomly on one side of the body. RESULTS: Kaplan-Meier survival analysis suggested that median time to heal with application of EGF plus silver sulfadiazine cream was 9 days, in comparison with 15 days for silver sulfadiazine cream alone (log-rank test, P=0.0003). No intervention-related adverse effect was observed during the study. CONCLUSIONS: EGF can significantly reduce healing time of skin lesions in patients with pemphigus vulgaris, at least when this cream base is applied (Cochrane skin group identifier: CSG20). 相似文献
140.
急性脑卒中患者应激性高血糖危险因素分析 总被引:1,自引:0,他引:1
目的 探讨重症监护室(ICU)急性脑卒中患者应激性高血糖的危险因素。方法对50例急性(发病5d内1非糖尿病脑卒中患者监测血糖7-14d,比较高血糖及正常血糖两组患者年龄、糖皮质激素、临床肺部感染评分等对血糖的影响。结果高血糖组临床肺部感染评分(CPIS)为4.77±2.11,显著高于正常血糖组的3.36±2.36(P〈0.05),急性生理学及慢性健康状况评分(APACHEⅡ)高血糖组为16.23+5.40,也显著高于正常血糖组的12.43±3.83,有显著性差异(P〈0.01)。结论CHS和APACHEⅡ升高可能是ICU非糖尿病卒中后应激性高血糖的危险因素。 相似文献