全文获取类型
收费全文 | 264241篇 |
免费 | 24443篇 |
国内免费 | 16576篇 |
专业分类
耳鼻咽喉 | 2453篇 |
儿科学 | 2765篇 |
妇产科学 | 3993篇 |
基础医学 | 33741篇 |
口腔科学 | 4899篇 |
临床医学 | 34458篇 |
内科学 | 41292篇 |
皮肤病学 | 3072篇 |
神经病学 | 15727篇 |
特种医学 | 9737篇 |
外国民族医学 | 144篇 |
外科学 | 28088篇 |
综合类 | 38531篇 |
现状与发展 | 56篇 |
一般理论 | 24篇 |
预防医学 | 15543篇 |
眼科学 | 7943篇 |
药学 | 26809篇 |
192篇 | |
中国医学 | 12957篇 |
肿瘤学 | 22836篇 |
出版年
2024年 | 535篇 |
2023年 | 3303篇 |
2022年 | 8009篇 |
2021年 | 11906篇 |
2020年 | 8785篇 |
2019年 | 8033篇 |
2018年 | 8957篇 |
2017年 | 7764篇 |
2016年 | 7330篇 |
2015年 | 11020篇 |
2014年 | 13599篇 |
2013年 | 12058篇 |
2012年 | 17875篇 |
2011年 | 19762篇 |
2010年 | 11584篇 |
2009年 | 9303篇 |
2008年 | 12737篇 |
2007年 | 12821篇 |
2006年 | 12860篇 |
2005年 | 12678篇 |
2004年 | 8264篇 |
2003年 | 7860篇 |
2002年 | 6682篇 |
2001年 | 9091篇 |
2000年 | 9458篇 |
1999年 | 9220篇 |
1998年 | 4709篇 |
1997年 | 4365篇 |
1996年 | 3380篇 |
1995年 | 3082篇 |
1994年 | 2573篇 |
1993年 | 1773篇 |
1992年 | 3657篇 |
1991年 | 3151篇 |
1990年 | 2698篇 |
1989年 | 2459篇 |
1988年 | 2218篇 |
1987年 | 1931篇 |
1986年 | 1672篇 |
1985年 | 1353篇 |
1984年 | 875篇 |
1983年 | 664篇 |
1982年 | 366篇 |
1981年 | 303篇 |
1980年 | 233篇 |
1979年 | 405篇 |
1978年 | 126篇 |
1975年 | 118篇 |
1974年 | 131篇 |
1973年 | 141篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Whole-body inflammation in trauma patients. An autopsy study 总被引:8,自引:0,他引:8
H K Nuytinck X J Offermans K Kubat J A Goris 《Archives of surgery (Chicago, Ill. : 1960)》1988,123(12):1519-1524
In a review of autopsy specimens and reports in 35 trauma cases, we found signs of generalized inflammation and tissue damage with increases in organ weights in organs not primarily injured. These abnormalities occurred independent of the time of death and were also found in patients who died of brain injury alone. The most pronounced signs of inflammation and increases in organ weights were found when the adult respiratory distress syndrome, hypovolemic shock, or multiple organ failure were the causes of death. These findings are similar to those found in several organs of rabbits after four hours of complement activation in combination with 20 minutes of hypoxia. Therefore, the autopsy findings in this series of trauma patients might represent the morphologic features of adult respiratory distress syndrome and multiple organ failure in an early, preclinical stage. 相似文献
993.
竹黄颗粒剂Ⅱ号对应激小鼠皮肤肥大细胞影响的实验研究 总被引:6,自引:0,他引:6
目的:阐明竹黄颗粒剂Ⅱ号治疗现的作用机制。方法:应用形态学方法观察竹黄Ⅱ号对应激小鼠皮肤肥大细胞的影响。结果:束缚应激诱导小鼠皮肤肥大细胞脱颗粒,竹黄Ⅱ号抑制了此效应。结论:提示竹黄颗粒剂Ⅱ号可抑制心理应激诱导的皮肤肥大细胞脱颗粒,可能是其治疗银屑病的疗效机制之一。 相似文献
994.
黄连细胞二步法悬浮培养生产黄连生物碱类成分的探索 总被引:6,自引:0,他引:6
为提高用植物细胞培养生产镒生代谢产物的单位产量,作者对黄连细胞采用二步法悬浮培养生产黄连生物碱进行了探索。结果显示:黄连细胞采用一步法悬浮培养6周,细胞干,鲜重产率分别为20.96g/L和174.92g/L,增重约700%,细胞中总生物碱含量为14.79mg/g.cell dw,培养基中生物碱量为12.96mg/L,每升培养液共可收获生物碱323mg。采用先在生长培养基中培养3周,在合成碱量为12 相似文献
995.
小儿疳证源流考 总被引:1,自引:0,他引:1
刘书奎 《Zhonghua yi shi za zhi (Beijing, China : 1980)》1997,27(4):218-221
疳作为一个病名,最早见于隋《诸病源候论》。首先将疳证作为儿科专有疾病者,为宋初《太平圣惠方》。本病分类最全面,收集方剂最丰富当推宋《幼幼新书》。南宋出版的《小儿卫生总微论方》首次将疳证归类为五疳。本草文献中对本病贡献最大的为明《本草纲目》。清《温病条辨》首次将本病治法作全面总结。1994年国家中医药管理局颁布的《中医病证诊断疗效标准》首次以法规的形式将本病作了统一规范 相似文献
996.
Lead exposure and intelligence in 7-year-old children: the Yugoslavia Prospective Study. 总被引:5,自引:1,他引:4 下载免费PDF全文
G A Wasserman X Liu N J Lolacono P Factor-Litvak J K Kline D Popovac N Morina A Musabegovic N Vrenezi S Capuni-Paracka V Lekic E Preteni-Redjepi S Hadzialjevic V Slavkovich J H Graziano 《Environmental health perspectives》1997,105(9):956-962
For a prospective study of lead exposure and early development, we recruited pregnant women from a lead smelter town and from an unexposed town in Yugoslavia and followed their children through 7 years of age. In this paper we consider associations between lifetime lead exposure, estimated by the area under the blood lead (BPb) versus time curve (AUC7), and intelligence, with particular concern for identifying lead's behavioral signature. The Wechsler Intelligence Scales for Children-Version III (WISC-III) was administered to 309 7-year-old children, 261 of whom had complete data on intelligence, blood lead, and relevant sociodemographic covariates (i.e., Home Observation for the Measurement of the Environment (HOME), birth weight, gender, sibship size, and maternal age, ethnicity, intelligence, and education). These showed anticipated associations with 7-year intelligence, explaining 41-4% of the variance in Full Scale, Performance, and Verbal IQ. Before covariate adjustment, AUC7 was unrelated to intelligence; after adjustment, AUC7 explained a significant 2.8%-4.2% of the variance in IQ. After adjustment, a change in lifetime BPb from 10 to 30 micro/dl related to an estimated decrease of 4.3 Full Scale IQ points; estimated decreases for Verbal and Performance IQ were 3.4 and 4.5 points, respectively. AUC7 was significantly and negatively related to three WISC-III factor scores: Freedom from Distractibility, Perceptual Organization, and Verbal Comprehension; the association with Perceptual Organization was the strongest. Consistent with previous studies, the IQ/lead association is small relative to more powerful social factors. Findings offer support for lead's behavioral signature; perceptual-motor skills are significantly more sensitive to lead exposure than are the language-related aspects of intelligence. 相似文献
997.
头孢氨苄缓释片在健康人体内的生物利用度和药物动力学 总被引:2,自引:0,他引:2
目的:比较头孢氨苄缓释片和普通胶囊的生物利用度和药物动力学。方法:10例健康志愿者分别单剂量口服500mg头孢氨苄缓释片和普通胶囊,血药浓度测定方法为HPLC法。结果:两种剂型体内过程均符合一室开放模型,缓释片的达峰时间(Tmax)为(2.58±0.59)h,峰浓度(Cmax)为(10.08±1.68)μg/ml.吸收速率常数(Ka)为(0.90±0.53)/h,消除速率常数(Ke)为(0.26±0.02)/g,半衰期(T1/2)为(2.67±0.23)h,清除率(Cl)为(6.93±1.71)L/h,分布容积(Vd)为(26.66±6.72)L,药一时曲线下面积(AUC)为(48.31±9.32)μg·h/ml。两种剂型T一C一Ka、Ke、T1/2和Cl均存在显著性差异(P<0.01),Vd、AUC无显著性差异(P>0.05);缓释片的相对生物利用度为(104.90±8.35)%。结论:缓释片的吸收减慢,Tmax推迟,T1/2延长,可减少服药次数,提高药物治疗的顺应性。 相似文献
998.
999.
葛根对小白鼠免疫功能的影响 总被引:8,自引:1,他引:7
从免疫学方面探讨中药葛根的强身健体作用。方法 :用 10 0 %葛根水浸出液定期给小鼠灌胃 ,然后检测小鼠抗体产生能力、淋巴细胞转化率、巨噬细胞吞噬的功能。结果 :用药组小白鼠以上免疫学指标均有显著增强作用 ,与对照组相比有非常显著性差异 (P <0 .0 1)。未见有副作用。结论 :口服葛根可明显增强机体免疫功能。 相似文献
1000.
N Verbruggen X J Hua M May M Van Montagu 《Proceedings of the National Academy of Sciences of the United States of America》1996,93(16):8787-8791
In many plants, osmotic stress induces a rapid accumulation of proline through de novo synthesis from glutamate. This response is thought to play a pivotal role in osmotic stress tolerance [Kishor, P. B. K., Hong, Z., Miao, G.-H., Hu, C.-A. A. and Verma, D. P. S. (1995) Plant Physiol. 108, 1387-1394]. During recovery from osmotic stress, accumulated proline is rapidly oxidized to glutamate and the first step of this process is catalyzed by proline oxidase. We have isolated a full-length cDNA from Arabidopsis thaliana, At-POX, which maps to a single locus on chromosome 3 and that encodes a predicted polypeptide of 499 amino acids showing significant similarity with proline oxidase sequences from Drosophila and Saccharomyces cerevisiae (55.5% and 45.1%, respectively). The predicted location of the encoded polypeptide is the inner mitochondrial membrane. RNA gel blot analysis revealed that At-POX mRNA levels declined rapidly upon osmotic stress and this decline preceded proline accumulation. On the other hand, At-POX mRNA levels rapidly increased during recovery. Free proline, exogenously added to plants, was found to be an effective inducer of At-POX expression; indeed, At-POX was highly expressed in flowers and mature seeds where the proline level is higher relative to other organs of Arabidopsis. Our results indicate that stress- and developmentally derived signals interact to determine proline homeostasis in Arabidopsis. 相似文献