全文获取类型
收费全文 | 12428篇 |
免费 | 1085篇 |
国内免费 | 355篇 |
专业分类
耳鼻咽喉 | 75篇 |
儿科学 | 168篇 |
妇产科学 | 283篇 |
基础医学 | 1651篇 |
口腔科学 | 233篇 |
临床医学 | 1179篇 |
内科学 | 1761篇 |
皮肤病学 | 149篇 |
神经病学 | 658篇 |
特种医学 | 375篇 |
外国民族医学 | 3篇 |
外科学 | 1507篇 |
综合类 | 1451篇 |
现状与发展 | 3篇 |
预防医学 | 1216篇 |
眼科学 | 93篇 |
药学 | 1061篇 |
8篇 | |
中国医学 | 399篇 |
肿瘤学 | 1595篇 |
出版年
2024年 | 19篇 |
2023年 | 184篇 |
2022年 | 299篇 |
2021年 | 461篇 |
2020年 | 430篇 |
2019年 | 405篇 |
2018年 | 377篇 |
2017年 | 418篇 |
2016年 | 468篇 |
2015年 | 457篇 |
2014年 | 914篇 |
2013年 | 968篇 |
2012年 | 671篇 |
2011年 | 803篇 |
2010年 | 609篇 |
2009年 | 610篇 |
2008年 | 627篇 |
2007年 | 658篇 |
2006年 | 559篇 |
2005年 | 447篇 |
2004年 | 390篇 |
2003年 | 332篇 |
2002年 | 276篇 |
2001年 | 266篇 |
2000年 | 228篇 |
1999年 | 190篇 |
1998年 | 176篇 |
1997年 | 138篇 |
1996年 | 129篇 |
1995年 | 132篇 |
1994年 | 137篇 |
1993年 | 118篇 |
1992年 | 97篇 |
1991年 | 92篇 |
1990年 | 81篇 |
1989年 | 62篇 |
1988年 | 58篇 |
1987年 | 59篇 |
1986年 | 45篇 |
1985年 | 77篇 |
1984年 | 60篇 |
1983年 | 58篇 |
1982年 | 52篇 |
1981年 | 43篇 |
1980年 | 30篇 |
1979年 | 38篇 |
1978年 | 28篇 |
1977年 | 20篇 |
1976年 | 24篇 |
1975年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
81.
82.
成骨细胞与血管内皮细胞联合培养的生物学特性 总被引:7,自引:1,他引:6
目的探讨成骨细胞与血管内皮细胞联合培养的生物学特性. 方法取2周龄乳兔颅盖骨及肾脏皮质传代培养制备成骨细胞(A组)、血管内皮细胞(B组)及成骨细胞与血管内皮细胞联合培养(C组),用Ⅰ型胶原和血管Ⅷ因子免疫细胞化学染色鉴定成骨细胞和血管内皮细胞,倒置相差显微镜和组织学染色观察细胞的生长特性和细胞相容性,检测碱性磷酸酶 (alkaline phosphatase,ALP)活性,观察血管内皮细胞对成骨细胞产生的ALP活性有无影响,MTT法检测细胞活力,分析细胞生长和增殖情况. 结果免疫细胞化学染色证实,培养的细胞为成骨细胞和血管内皮细胞.倒置相差显微镜、HE和Masson染色均显示两种细胞混合生长良好.ALP检测结果:C组ALP活性明显高于A组和B组(P<0.01),A组高于B组(P<0.05).MTT检测结果表明:C组细胞早期增殖较慢,而后期增殖较快. 结论成骨细胞与血管内皮细胞具有良好的相容性,血管内皮细胞能够增强成骨细胞的ALP活性,提高成骨细胞的增殖能力.联合培养细胞具有很强的增殖潜能. 相似文献
83.
84.
乙型和丙型肝炎病毒血清学标志与原发性肝癌关系的研究 总被引:4,自引:0,他引:4
目的:研究原发性肝齐(PHC)病人中乙型肝炎病毒(HBV)和丙型肝炎病毒(HCV)血清学标志的分布状况。方法:选择全市40家医院收治住院确诊PHC患者100例,用ELISA法进行HBsAg、抗-HBs、HBeAg、抗-HBe和抗-HBc和抗-HCV检测。结果:PHC组HBV和抗-HCV的感染率分别为89.0%和8.0%,明显高于对照组(P<0.001),两者的ARP(归因危险度百分比)分别为93.0%和88.0%。HBV血清学标志在PHC的分布较高的是HBsAg、抗-HBc和HBsAg、HBeAg、抗-HBc组合。协同作用分析结果显示HBsAg、抗-HCV同时阳性者的OR值为46.28,较单一指标阳性的OR为高,也高于两者单独阳性的OR值之和。结论:HBV和HCV感染均是PHC发生的主要病原学因素。HBV是肝癌发生的主要因素。 相似文献
85.
目的:观察代谢综合征(MS)患者血管内皮损伤标志物血管性假性血友病因子抗原(vWF:Ag)、凝血酶调节蛋白(TM)及超敏C反应蛋白(Hs-CRP)的水平变化及其与胰岛素抵抗的关系。方法:测定67例MS患者(其中合并冠心病31例)及35例健康对照组TM、vWF:Ag、Hs-CRP、空腹胰岛素(Fins)水平,计算胰岛素抵抗指数(IR)。结果:单纯MS组(B组)TM、vWF:Ag、Hs-CRP水平明显高于对照组(A组),P<0.05;MS合并冠心病组(C组)TM、vWF:Ag、Hs-CRP水平均高于A组和B组,差异有显著性统计学意义(P<0.05)。单因素直线相关分析表明TM、vWF:Ag、Hs-CRP与IR显著正相关(r分别为0.32、0.36、0.38)。结论:MS患者血管内皮损伤标志物、CRP水平升高,且与IR抵抗有关。 相似文献
86.
本文报道人精液抑制素的制备及其生物学特性。收集的新鲜人精液经乙醇沉淀和丙酮冲洗,获得的粗提物经Sephadex G100处理,产生具有高活性抑制素hP2组分。应用hP2测定使去势雄性大鼠增高的血清FSH水平降低。其生物特性:hP2的生物活性按单位重量计算为粗提物的10倍以上,包含16种氨基酸,通过SDS-PAGE计算分子量为11,500道尔顿。 相似文献
87.
V. EVANGELISTA G. DE BERARDIS† L. TOTANI F. AVANZINI‡ C. B. GIORDA§ L. BRERO¶ G. LEVANTESI G. MARELLI†† M. PUPILLO‡‡ G. IACUITTI‡ G. POZZOLI‡ P. DI SUMMA¶ E. NADA§ G. DE SIMONE G. DELL'ELBA C. AMORE S. MANARINI R. PECCE A. MAIONE† G. TOGNONI† A. NICOLUCCI† 《Journal of thrombosis and haemostasis》2007,5(11):2197-2203
BACKGROUND: The percentage of diabetic patients who do not benefit from the protective effect of aspirin is larger than in other populations at cardiovascular risk. OBJECTIVE: We compared the ability of aspirin to suppress TxA2 and platelet activation in vivo, in type-2 diabetics vs. high-risk non-diabetic patients. METHODS: Urinary 11-dehydro-TXB2, plasma sCD40 L, and sP-selectin were measured, together with indices of low-grade inflammation, glycemic control, and lipid profile, in 82 patients with type-2 diabetes and 39 without diabetes, treated with low doses of aspirin. RESULTS: Urinary 11-dehydro-TxB2, plasma sCD40L and sP-selectin were significantly higher in diabetics than in controls: [38.9 (27.8-63.3) vs. 28.5 (22.5-43.9) ng mmol(-1) of creatinine, P = 0.02], [1.06 (0.42-3.06) vs. 0.35 (0.22-0.95) ng mL(-1); P = 0.0001], [37.0 (16.8-85.6) vs. 20.0 (11.2-35.6) ng mL(-1), P = 0.0001], respectively. The proportion of individuals with diabetes increased across quartiles of 11-dehydro-TxB2, sCD40L, and sP-selectin, with the highest quartiles of 11-dehydro-TxB2, sCD40L and sP-selectin, including 66%, 93.3%, and 93.3% of individuals with diabetes. Markers of platelet activation positively correlated with indices of glycemic control but not with markers of low-grade inflammation. CONCLUSIONS: Platelet dysfunction associated with insufficient glycemic control, may mediate persistent platelet activation under aspirin treatment. 相似文献
88.
The effects of brisk walking on markers of bone and calcium metabolism in postmenopausal women 总被引:5,自引:0,他引:5
Weight-bearing exercise has been shown to maintain or increase bone mass in younger as well as older individuals but the mechanisms
by which mechanical loading affects bone metabolism are not known in detail. Twelve postmenopausal women participated in a
single bout of brisk walking (50% of VO2 max) for 90 minuttes. Calciotropic hormones and markers of type I collagen formation (PICP) and degradation (ICTP) were measured
before the exercise, and 1, 24, and 72 hours following the exercise. Total body bone mineral content (BMC) and density (BMD)
were measured by dual energy X-ray absorptiometry (DXA). Brisk walking did not induce any significant changes in the concentrations
of ionized calcium, parathyroid hormone (PTH), calcitonin, or osteocalcin. A significant increase of PICP was noted 24 and
72 hours (P<0.01) after exertion and a significant decrease in the concentration of serum ICTP at 1 hour (P<0.05) was followed by an increase at 72 hours (P<0.001). There was no significant difference between the increases in the concentrations of PICP and ICTP at 72 hours. Strong
inverse correlations between the basal levels of PTH and BMD (r=−0.78;P<0.01) as well as between osteocalcin and BMD (r=−0.83;P<0.01) were noticed. The changes in serum levels of bone collagen markers indicate an altered bone collagen turnover due to
this moderate endurance exercise. The results also support the fact that serum levels of PTH as well as those of osteocalcin
are associated with total body BMD in postmenopausal women. 相似文献
89.
目的研究多方法、多生物学标志在产肠毒素性大肠埃希菌同源克隆鉴定中的作用。方法在毒力基因检测和分型基础上,首次采用质粒分析法结合多位点酶电泳法,对ETEC同源克隆进行了综合研究。结果7个毒力基因型的206株散发ETEC菌株经质粒图谱分型后,共可分成93个质粒型,有140株ETEC具有独特的基因型;进一步用多位点酶电泳分型,206株ETEC可被分成148个ET型,3种方法综合,共有190株ETEC具有独特的基因型。结论多方法、多生物学标志在同源克隆鉴定中能提供更多、更可靠的信息。 相似文献
90.
Alexandros GERAKIS Angeliki BARBATSI Sophia SARANTI Theodora STROGYLOU Dimitrios VALIS 《Nephrology (Carlton, Vic.)》1998,4(5-6):403-406
SUMMARY: We studied the effect of haemodialysis on the serum levels of tumour markers in 78 patients, 49 men and 29 women with a mean age of 61 ± 2 years, who had been undergoing haemodialysis for 39 ± 10 months. No patient had any clinical evidence of malignancy. Serum values of carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), squamous-cell-carcinoma-related antigen (SCC), neuron-specific enolase (NSE), tissue polypeptide antigen (TPA), CA 15-3, CA 19–9, and among males prostate-specific antigen (PSA) were determined before and after dialysis. Postdialysis values, after being corrected for haemoconcentration, were compared with predialysis values. A significant increase of 32% was observed in NSE levels ( P <0.001) and of 21% in CA 15-3 ( P <0.001) after haemodialysis. A lesser, but still statistically significant, increase (8-12%) was observed in SCC, AFP and CEA levels ( P <0.05), while the values of the remaining three markers remained unchanged. In conclusion, an increase in some tumour markers was found in our patients after dialysis, a finding which requires further investigation. 相似文献