全文获取类型
收费全文 | 908篇 |
免费 | 156篇 |
国内免费 | 215篇 |
专业分类
化学 | 1256篇 |
晶体学 | 2篇 |
综合类 | 13篇 |
物理学 | 8篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 58篇 |
2021年 | 55篇 |
2020年 | 62篇 |
2019年 | 33篇 |
2018年 | 31篇 |
2017年 | 39篇 |
2016年 | 70篇 |
2015年 | 59篇 |
2014年 | 58篇 |
2013年 | 98篇 |
2012年 | 65篇 |
2011年 | 55篇 |
2010年 | 52篇 |
2009年 | 60篇 |
2008年 | 50篇 |
2007年 | 57篇 |
2006年 | 59篇 |
2005年 | 47篇 |
2004年 | 38篇 |
2003年 | 67篇 |
2002年 | 18篇 |
2001年 | 24篇 |
2000年 | 18篇 |
1999年 | 7篇 |
1998年 | 13篇 |
1997年 | 21篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有1279条查询结果,搜索用时 15 毫秒
91.
92.
《中国化学快报》1999,(6)
HowiinolAI',anovellactoneisolatedfromtheethanolicextractsoftherootandsternbarkofGoniolhanlush()TI)iiMerr.(Annoaceae)inourlaboratory.hasbeenshowntopossesssignificantantitullloractivitiestowardhumantumor117vilroandI,71'if'oandfoxytoxlcit}.Recently.wehavesynthesized1anditsderivativeswitllditTerentestergroupsstartingfromcommerciallyavailablea-D-glucoheptonic-y-lactone.Inordertotindtheirrelationshipofstructureandactivityandtosearchfordrugswithmorepotentantitumoractivity.wehavesynthesized( )8-O-… 相似文献
93.
94.
95.
Lubov' V. Snegur Yury S. Nekrasov Nataliya S. Sergeeva Zhanna V. Zhilina Vera V Gumenyuk Zoya A. Starikova Alexander A. Simenel Nataliya B. Morozova Irina K. Sviridova Valery N. Babin 《应用有机金属化学》2008,22(2):139-147
The toxicity of ferrocenylethyl benzotriazole ( 1 ) and other ferrocene compounds including ferrocenylmethyl benzimidazoles ( 4,5,6,11 ), ferricenium salts ( 3,9,10 ) and ferrocenylmethyl adenine ( 7 ), was studied. All ferrocene complexes under investigation showed low or medium toxicities. On the basis of an earlier model of chemical carcinogenesis, the antitumor activity of ferrocenylalkyl azoles 1, 8 and ferricenium salts 9, 10 was studied in vivo in the so‐called sub‐capsular test on human tumors. This effectiveness was compared with that of cisplatin. A series of ferrocenylalkyl azoles were synthesized by interacting azoles either with α‐hydroxyalkyl ferrocenes FcC(OH)R1R2 in organic solvent in the presence of aqueous HBF4 in quantitative yields or with trimethyl(aminomethyl)ferrocene iodide in an aqueous‐basic medium in good yields. The X‐ray determinations of molecular and crystal structures of α‐(1‐benzotriazolyl)ethylferrocene ( 1 ) and α‐(1‐naphthatriazolyl)ethylferrocene ( 12 ) were performed. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
96.
97.
A series of novel tetraphenylantimony derivatives of exo‐7‐oxa‐bicyclo[2,2,1] heptane (ene)‐3‐arylamide‐2‐acid of the general formula Ph4SbO2CCHCHCH2CH2CH(O)HCONHAr (Ar = Ph,4‐ClC6H4, 4‐BrC6H4, 3‐BrC6H4, 4‐F‐3‐ClC6H3 and 4‐MeC6H4) have been synthesized and characterized by elemental analysis, IR, 1H NMR and mass spectra. The crystal structure of Ph4SbO2CCHCHCH2CH2CH(O)HCONHC6H4CH3·CHCl3 was determined by X‐ray diffraction. Five human neoplastic cell lines (HL‐60, KB, Bel‐7402, BGC‐823 and HCT‐8) were used to screen these compounds. The results indicate that these compounds at 10 µM show certain in vitro antitumor activities. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
98.
Knoevenagel condensate Schiff base ligands [L = 3‐cinnamalideneacetylacetone‐thiosemicarbazone (CAT)/3‐cinnama‐ lideneacetylacetoneethylthiosemicarbazone (CAET)/3‐cinnamalideneacetylacetonephenylthiosemicarbazone (CAPT)] and their copper/zinc complexes were synthesized. They were characterized by analytical and spectral techniques. From these data it was found that the ligands adopt square‐planar geometry on metalation with Cu2+ and Zn2+. To evaluate the antitumor and cytotoxic activity of the synthesized complexes in mice and human cancer cell lines, the antitumor activity of the complexes was evaluated against an Ehrlich ascites carcinoma (EAC) tumor model. The activity was assessed using survival time and short‐term in vitro cytotoxic activity. Oral administration of complexes (100 mg/kg) increased the survival time. The cytotoxic activity of complexes was evaluated using human breast cancer (MDA‐MB‐231), colon cancer (HCT‐116) and nonsmall lung cancer (NCI‐H‐23) cell lines. Both the complexes possessed significant antitumor and cytotoxic activity on EAC and human cancer cell lines. The in vitro antimicrobial screening effect of the investigated compounds was also tested against the various organisms by well diffusion method. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
99.
100.
Anserinones A and B are natural products that have been shown to have potential anticancer, antifungal, and antibacterial properties. This work entails the novel synthesis of these natural products. 相似文献