全文获取类型
收费全文 | 155206篇 |
免费 | 6651篇 |
国内免费 | 511篇 |
专业分类
耳鼻咽喉 | 2594篇 |
儿科学 | 4632篇 |
妇产科学 | 3524篇 |
基础医学 | 20879篇 |
口腔科学 | 5588篇 |
临床医学 | 9783篇 |
内科学 | 37754篇 |
皮肤病学 | 4994篇 |
神经病学 | 12458篇 |
特种医学 | 3711篇 |
外国民族医学 | 2篇 |
外科学 | 18726篇 |
综合类 | 982篇 |
一般理论 | 43篇 |
预防医学 | 15161篇 |
眼科学 | 3360篇 |
药学 | 10896篇 |
1篇 | |
中国医学 | 871篇 |
肿瘤学 | 6409篇 |
出版年
2023年 | 995篇 |
2022年 | 1668篇 |
2021年 | 4149篇 |
2020年 | 2061篇 |
2019年 | 3933篇 |
2018年 | 5649篇 |
2017年 | 3337篇 |
2016年 | 3193篇 |
2015年 | 3598篇 |
2014年 | 4798篇 |
2013年 | 6895篇 |
2012年 | 10797篇 |
2011年 | 11627篇 |
2010年 | 6138篇 |
2009年 | 4765篇 |
2008年 | 8960篇 |
2007年 | 9484篇 |
2006年 | 8775篇 |
2005年 | 8746篇 |
2004年 | 7808篇 |
2003年 | 7273篇 |
2002年 | 6737篇 |
2001年 | 4390篇 |
2000年 | 4953篇 |
1999年 | 3887篇 |
1998年 | 903篇 |
1997年 | 709篇 |
1996年 | 581篇 |
1995年 | 513篇 |
1994年 | 406篇 |
1993年 | 345篇 |
1992年 | 1493篇 |
1991年 | 1257篇 |
1990年 | 1133篇 |
1989年 | 961篇 |
1988年 | 831篇 |
1987年 | 758篇 |
1986年 | 759篇 |
1985年 | 655篇 |
1984年 | 463篇 |
1983年 | 394篇 |
1979年 | 428篇 |
1975年 | 306篇 |
1974年 | 380篇 |
1973年 | 386篇 |
1972年 | 328篇 |
1971年 | 357篇 |
1970年 | 323篇 |
1969年 | 345篇 |
1968年 | 304篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Mamo Gebrezgiabher Sren Schlittenhardt Cyril Rajnk Juraj Kuchr Assefa Sergawie Juraj ernk Mario Ruben Madhu Thomas Roman Bo
a 《RSC advances》2022,12(33):21674
The triangulo-{Er3} complex [Er3Cl(o-van)3(OH)2(H2O)5]Cl3·nH2O (n = 9.4; H(o-van) = o-vanillin) (1) was generated by an in situ method. The isolated Er(iii) complex 1 was characterized by elemental analysis and molecular spectroscopy. The results of single crystal X-ray diffraction studies have shown that 1 is built up of trinuclear [Er3Cl(o-van)3(OH)2(H2O)5]3+ complex cations, chloride anions and water solvate molecules. Within the complex cation the three Er(iii) central atoms are placed at the apexes of a triangle which are bridged by three (o-van)− ligands with additional chelating functions and two μ3-OH− ligands. Additionally five aqua and one chlorido ligands complete the octa-coordination of the three Er(iii) atoms. AC susceptibility measurements reveal that the compound exhibits slow magnetic relaxation with two relaxation modes.The triangulo-{Er3} complex [Er3Cl(o-van)3(OH)2(H2O)5]Cl3·nH2O (n = 9.4; H(o-van) = o-vanillin) (1) was generated by an in situ method. 相似文献
994.
Prada Diddier Baccarelli Andrea A. Terry Mary Beth Valdéz Leonora Cabrera Paula Just Allan Kloog Itai Caro Haydee García-Cuellar Claudia Sánchez-Pérez Yesennia Cruz Rodrigo Diaz-Chávez Jose Cortés Carlo Pérez Delia Meneses-García Abelardo Cantú-de-León David Herrera Luis A. Bargalló Enrique 《Breast cancer research and treatment》2021,187(2):525-533
Breast Cancer Research and Treatment - Many patients seek breast reconstruction following mastectomy. Debate exists regarding the best reconstructive option. The authors evaluate outcomes comparing... 相似文献
995.
996.
997.
The new cembrane diterpenes leptodienone A (2) and leptodienone B (3) and the known compounds lopholide, lophodiol B, lophodione, and lophotoxin (1) have been isolated from the gorgonian Leptogorgia laxa collected in the Gulf of California. The structures of the new metabolites have been established by spectroscopic techniques. The in vitro cytotoxicity of the new compounds has been tested against three human tumor cell lines. 相似文献
998.
Cerda-García-Rojas CM Catalán CA Muro AC Joseph-Nathan P 《Journal of natural products》2008,71(6):967-971
The agreement between theoretical and experimental vibrational circular dichroism curves of (4R,9R,10R)-(+)-african-1(5)-ene-2,6-dione (1) and (4R,9S,10R)-lippifoli-1(6)-en-5-one (2), isolated from the widely used plant Lippia integrifolia, allowed the determination of the conformation and absolute configuration of 1 and confirmed both structural features for 2. Molecular modeling of 1 and 2 was carried out by means of a systematic and a Monte Carlo search protocol followed by geometry optimization employing density functional theory calculations with the B3LYP/6-31G(d), B3LYP/DGDZVP, and/or B3PW91/DGDZVP2 functionals/basis sets. Validation of the minimum energy conformations for both tricyclic substances was achieved by comparison of the experimental and theoretical vicinal (1)H-(1)H NMR coupling constants obtained by DFT-GIAO calculations. 相似文献
999.
Grance SR Teixeira MA Leite RS Guimarães EB de Siqueira JM de Oliveira Filiu WF de Souza Vasconcelos SB do Carmo Vieira M 《Journal of ethnopharmacology》2008,117(1):28-33
AIM OF THE STUDY: This investigation evaluated the effect of a hydroethanolic extract of Baccharis trimera on pregnant Wistar rats, once the plant is well-known consumed in pregnancy and little is known on its potentially toxic effects on pregnant women. MATERIAL AND METHODS: Thirty-five female rats were distributed into three groups. Those in treatments 1 and 2 were given 8.4 mg/kg of the extract orally from gestational day (GD) 1 to 19 and from GD 6 to 15, respectively, whereas those in the control group received distilled water orally from GD 1 to 19. Body weights were recorded on GD 1, 6, 15, and 20. On GD 20 animals were anesthetized, blood samples were collected and maternal livers, kidneys, and spleens were weighed and processed for histological studies. RESULTS: No clinical signs of maternal toxicity and no changes in hematological parameters were observed. Urea levels and kidney weights differed significantly between animals receiving treatment 1 and controls. Histopathological alterations were found in kidneys and livers in both treatment groups. CONCLUSIONS: The hydroethanolic extract of Baccharis trimera administered to pregnant rats at 8.4 mg/kg was toxic to maternal kidney and liver cells, although such alterations are reversible once administration is discontinued. 相似文献
1000.