全文获取类型
收费全文 | 79328篇 |
免费 | 6904篇 |
国内免费 | 4563篇 |
专业分类
耳鼻咽喉 | 925篇 |
儿科学 | 992篇 |
妇产科学 | 789篇 |
基础医学 | 9853篇 |
口腔科学 | 1378篇 |
临床医学 | 8726篇 |
内科学 | 11531篇 |
皮肤病学 | 1413篇 |
神经病学 | 3934篇 |
特种医学 | 3905篇 |
外国民族医学 | 21篇 |
外科学 | 7977篇 |
综合类 | 12112篇 |
现状与发展 | 28篇 |
一般理论 | 7篇 |
预防医学 | 5387篇 |
眼科学 | 2349篇 |
药学 | 8656篇 |
67篇 | |
中国医学 | 3944篇 |
肿瘤学 | 6801篇 |
出版年
2024年 | 189篇 |
2023年 | 973篇 |
2022年 | 2469篇 |
2021年 | 3449篇 |
2020年 | 2476篇 |
2019年 | 2260篇 |
2018年 | 2451篇 |
2017年 | 2321篇 |
2016年 | 2461篇 |
2015年 | 3694篇 |
2014年 | 4585篇 |
2013年 | 4541篇 |
2012年 | 6636篇 |
2011年 | 7068篇 |
2010年 | 4670篇 |
2009年 | 4024篇 |
2008年 | 5012篇 |
2007年 | 4734篇 |
2006年 | 4470篇 |
2005年 | 3939篇 |
2004年 | 2980篇 |
2003年 | 2965篇 |
2002年 | 2475篇 |
2001年 | 1679篇 |
2000年 | 1403篇 |
1999年 | 1252篇 |
1998年 | 791篇 |
1997年 | 703篇 |
1996年 | 598篇 |
1995年 | 542篇 |
1994年 | 519篇 |
1993年 | 345篇 |
1992年 | 375篇 |
1991年 | 343篇 |
1990年 | 288篇 |
1989年 | 262篇 |
1988年 | 173篇 |
1987年 | 188篇 |
1986年 | 141篇 |
1985年 | 96篇 |
1984年 | 55篇 |
1983年 | 39篇 |
1982年 | 38篇 |
1981年 | 27篇 |
1980年 | 27篇 |
1979年 | 16篇 |
1978年 | 6篇 |
1975年 | 7篇 |
1973年 | 10篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Bone morphogenetic protein (BMP) was isolated from the bone matrix of swine and partially purified by means of differential precipitation and molecular sieve chromatography. The molecular weight of BMP estimated by SDS-gel electrophoresis was 19,000 dalton. Bioassay by implanting two milligrams of BMP fraction into thigh muscles of mice resulted in bone formation in 100% of the experimental animals.
相似文献
32.
γ射线照射对血小板活化的影响 总被引:4,自引:0,他引:4
目的:探讨γ射线照射对单采血小板保存过程中血小板活化的影响.方法:用细胞分离机单采血小板20人份,以27Gyy射线照射,标准条件下保存5天,间隔取样分别用RIA,ELISA方法检测血小板表面P-选择素(P-Selectin)、血浆中可溶性P-选择素(sP-Selectin)及β-血小板球蛋白(β-TG)含量.结果:在保存3d,5d后,照射组及对照组中血小板表面P-Selectin含量、血浆中sP-Selectin及β-TG含量与保存前比较差异显著(P<0.05),但是两组间比较无统计学差异(P>0.05),结论:γ射线照射不会促进血小板的活化. 相似文献
33.
铜绿假单胞菌全细胞脂肪酸气相色谱分析及应用 总被引:5,自引:0,他引:5
本研究用计算机控制,可程序升温的毛细管柱气相色谱(GC)仪分析48株铜绿假单胞菌标准株和临床株、部分常见假单胞菌、肠杆菌的细胞脂肪酸。结果表明:月桂烯酸(C12:1),月桂酸(C12:0)、十三碳烯酸(C13:1)、十三碳酸(C13:0)、肉豆劳动脑酸(C14:1)、十七碳稀酸(C17:1)、十七碳酸(C17:0)、硬脂酸(C18:0)和花生四烯酸(C20:4)是铜绿包菌有鉴别意义的脂肪酸,组成与 相似文献
34.
Jin Woo Kim M.D. Ho Shik Kim M.D. In Kyung Kim M.D. Mee Ran Kim M.D. Eun Young Cho B.S. Heung Kee Kim M.D. Joon Mo Lee M.D. Sung Eun Namkoong M.D. 《Gynecologic oncology》1998,69(3):230-236
Transforming growth factor-β1 (TGF-β1) is known to be a potent growth inhibitor for many cell types, including most epithelial cells. In skin keratinocytes, TGF-β1 has been shown to inhibit growth and to rapidly reduce c-mycexpression. However, the molecular mechanism of TGF-β1 action on cell growth of cervical carcinoma has not yet been elucidated. We thus assessed the effect of TGF-β1 on the growth of cervical carcinoma cell lines. Two cervical squamous carcinoma cell lines, CUMC-3 and CUMC-6, were incubated with varying concentrations of TGF-β1, and growth inhibition was evaluated with tetrazolium-based colorimetric assay. After culture in TGF-β1 for 24 h, inhibition of growth was detected in a dose-dependent manner at concentrations of 0.1–10 ng/ml in both cell lines. This effect of TGF-β1 on cultured carcinoma cells was associated with apoptotic process including oligonucleosomal ladder DNA and apoptotic body formations. Northern blot analysis revealed c-mycmRNA expression was suppressed by 10 ng/ml of TGF-β1 following 3 h of treatment in both cell lines. Western blot analysis showed that the level of p27Kip1protein was increased after TGF-β1 treatment in both cell lines. These results suggest that the mechanisms by which TGF-β1 inhibits the growth of cervical carcinoma are complex and may include effects on down-regulation of c-mycgene, and overexpression of p27Kip1protein. 相似文献
35.
Dr W. Q. Ge Z. C. Luo J. Jin Y. C. Huang S. Wang S. J. Lui 《Medical & biological engineering & computing》1998,36(1):22-26
A novel cardiokymograph system is introduced. The new system features a capacitance transducer with increased sensitivity
and can be used in multichannel measurements. The novelty of this technique is the injection of a current into the patient
coupled with the use of a capacitive displacement transducer and the possibility of multichannel monitoring. It provides for
the possibility of removing breath noise when some signal processing technique, such as adaptive filtering, is used. Further
investigation is needed to demonstrate clinical significance and pathologies. 相似文献
36.
37.
补肾中药对雄激素致不孕大鼠卵巢核仁组成区蛋白的影响 总被引:4,自引:0,他引:4
观察补肾中药对雄激素致不孕大鼠卵巢核仁组成区蛋白的影响。用SD雌性大鼠幼仔,出生9d龄注射丙酸睾丸酮,制成雄激素致不孕大鼠(ASR)模型。80d龄灌服补肾中药水溶液两周。100d龄心脏灌注处死。以核仁组成区蛋白嗜银染色(AgNOR)和增殖细胞核杭原(PcNA)为指标,观察卵巢颗粒细胞、间质腺细胞的形态学变化。结果:补肾中药能够使ASR卵巢颗粒细胞增殖、卵泡发育。治疗组的AgNOR和PcNA计数明显高于模型组,而与对照组之间无显著差异。结论:补肾中药的这种作用可能是通过调节了下丘脑-垂体-卵巢性腺功能的结果,从而促使卵巢颗粒细胞发育、卵泡成熟。 相似文献
38.
Effects of smoking and drinking on excretion of hippuric acid among toluene-exposed workers 总被引:1,自引:1,他引:0
Osamu Inoue Kazunori Seiji Takao Watanabe Haruo Nakatsuka Chui Jin Shi-Jie Liu Masayuki Ikeda 《International archives of occupational and environmental health》1993,64(6):425-430
Summary In order to investigate possible effects of smoking and drinking on the metabolism of toluence in occupational settings, 206 toluene-exposed men (mean age: 31.4 years) in shoemaking, painting, or surface-coating workshops together with 246 nonexposed control men (36.8 years) were studied for the time-weighted average intensities of exposure to toluene, hippuric acid concentration in shift-end urine samples, and the two social habits of smoking and drinking. The mean daily consumptions of cigarettes and ethanol were about 20 pieces and 10 g among smokers and drinkers, respectively. The geometric mean toluene concentration among the exposed subjects was about 20 ppm, with a maximum of 521 ppm. Regression analysis after classification of the subjects by smoking and drinking clearly demonstrated that the two social habits, when combined, markedly reduce the hippuric acid level in the urine of workers exposed to was a significant association between smoking and drinking habits, which hindered separate evaluation of the effects of the two habits on toluene metabolism. Comparison of the present results with the findings reported in the literature, however, suggested that the observed effects may be attributable to smoking rather than to drinking habits. 相似文献
39.
红细胞悬液中白细胞凋亡的研究 总被引:1,自引:0,他引:1
目的:研究低温和辐射对红细胞中残余自细胞凋亡及某些细胞因子水平的影响。方法:来自6名无偿献血者200ml全血分离制备悬浮红细胞,等份分装为10袋。除自身对照外均25Geyγ射线照射,然后置血库冰箱2℃-8℃保存。保存后3小时、2天、7天、14天和35天分别取样用化学法检测凋亡。保存期内第1、3、5周分别取样测定IL-1β、IL-6、IL-8和TNF-α含量。保存期末所有样品均进行血培养。结果:红细胞保存后第2天白细胞开始出现凋亡梯状条带,随时间延长而明显;对照组和照射组该持征条带差异不大,而两组的细胞因子含量都逐渐升高,且照射组升高幅度显著低于对照组;血培养呈阴性。结论:红细胞成分中的残余白细胞在体外低温环境下可发生凋亡。辐射可抑制体外成分血细胞因子增加,但辐射如何影响血液细胞的凋亡还有待进一步研究。 相似文献