全文获取类型
收费全文 | 686篇 |
免费 | 61篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 15篇 |
2017年 | 17篇 |
2016年 | 28篇 |
2015年 | 29篇 |
2014年 | 31篇 |
2013年 | 49篇 |
2012年 | 61篇 |
2011年 | 50篇 |
2010年 | 27篇 |
2009年 | 18篇 |
2008年 | 43篇 |
2007年 | 43篇 |
2006年 | 39篇 |
2005年 | 44篇 |
2004年 | 43篇 |
2003年 | 39篇 |
2002年 | 31篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 9篇 |
1993年 | 3篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1952年 | 1篇 |
1949年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有747条查询结果,搜索用时 15 毫秒
31.
Cortés-Ortiz Liliana Baiz Marcella D. Hermida-Lagunes Javier García-Orduña Francisco Rangel-Negrín Ariadna Kitchen Dawn M. Bergman Thore J. Dias Pedro A. D. Canales-Espinosa Domingo 《International journal of primatology》2019,40(1):114-131
International Journal of Primatology - Interspecific hybridization allows the introgression or movement of alleles from one genome to another. While some genomic regions freely exchange alleles... 相似文献
32.
33.
INTEGRATE: Model-based multi-omics data integration to characterize multi-level metabolic regulation
34.
Macrophage migration inhibitory factor in the human endometrium: expression and localization during the menstrual cycle and early pregnancy 总被引:10,自引:0,他引:10
Arcuri F Ricci C Ietta F Cintorino M Tripodi SA Cetin I Garzia E Schatz F Klemi P Santopietro R Paulesu L 《Biology of reproduction》2001,64(4):1200-1205
35.
36.
37.
38.
Messori L Marcon G Cinellu MA Coronnello M Mini E Gabbiani C Orioli P 《Bioorganic & medicinal chemistry》2004,12(23):6039-6043
The solution behaviour of some novel organogold(III) compounds was investigated, and their cytotoxic properties evaluated against a few human tumour cell lines (A2780/S, A2780/R, MCF7, HT29 and A549). Specifically, the following compounds were considered: [Au(bipy(dmb)-H)(2,6-xylidine-H)][PF(6)] (AuXyl) and [Au(bipy(dmb)-H)(p-toluidine-H)][PF(6)] (AuTol) (in which bipy(dmb)=6-(1,1-dimethylbenzyl)-2,2'-bipyridine), [Au(py(dmb)-H)(AcO)(2)] (AuPyAcO) (in which py(dmb)=2-(1,1-dimethylbenzyl)-pyridine) and [Au(pz(Ph)-H)Cl(3)]K (AuPzCl) (in which pz(Ph)=1-phenylpyrazole). The solution chemistry of these compounds, under physiological-like conditions, was investigated through UV-vis absorption and (1)H NMR spectroscopies. Significant cytotoxic effects in vitro were observed in selected cases. 相似文献
39.
Ghelli S Rinaldi M Barlocco D Gelain A Pecorari P Tondi D Rastelli G Costi MP 《Bioorganic & medicinal chemistry》2003,11(6):951-963
Thymidylate synthase (TS) (EC 2.1.1.45), an enzyme involved in the DNA synthesis of both prokaryotic and eukaryotic cells, is a potential target for the development of anticancer and antinfective agents. Recently, we described a series of phthalein and naphthalein derivatives as TS inhibitors. These compounds have structures unrelated to the folate (Non-Analogue Antifolate Inhibitors, NAAIs) and were selective for the bacterial versus the human TS (hTS). In particular, halogen-substituted molecules were the most interesting. In the present paper the halogen derivatives of variously substituted 3,3-bis(4-hydroxyphenyl)-1H,3H-naphtho[2,3-c]furan-1-one (1-5) and 3,3-bis(4-hydroxyphenyl)-1H,3H-naphtho[1,8-c,d]pyran-1-one (6-14) were synthesized to investigate the biological effect of halogen substitution on the inhibition and selectivity for the TS enzymes. Conformational properties of the naphthalein series were explored in order to highlight possible differences between molecules that show species-specific biological profile with respect to non species-specific ones. With this aim, the conformational properties of the synthesized compounds were investigated by NMR, in various solvents and at different temperatures, and by computational analysis. The apparent inhibition constants (K(i)) for Lactobacillus casei TS (LcTS) were found to range from 0.7 to 7.0 microM, with the exception of the weakly active iodo-derivatives (4, 10, 13); all] the compounds were poorly active against hTS. The di-halogenated compounds 7, 8, 14 showed the highest specificity towards LcTS, their specificity index (SI) ranging between 40 and >558. The di-halogenated 1,8-naphthalein derivatives (7-10) exhibited different conformational properties with respect to the tetra-haloderivatives. Though a clear explanation for the observed specificity by means of conformational analysis is difficult to find, some interesting conformational effects are discussed in the context of selective recognition of the compounds investigated by the LcTS enzyme. 相似文献
40.
Manna L Neglia G Marino M Gasparrini B Di Palo R Zicarelli L 《Zygote (Cambridge, England)》2003,11(1):17-22
The aim of this study was to identify a simple, rapid method for sex determination of in vitro produced buffalo embryos, amplifying Y-chromosome-specific repeat sequences by polymerase chain reaction (PCR). Buffalo oocytes collected from slaughtered animals were matured, fertilised and cultured in vitro for 7 days. On day 7 embryos were evaluated and divided in to six groups according to developmental stage (2, 4, 8, 16 cells, morulae and blastocyst). Each embryo was stored singly in phosphate-buffered saline at -20 degrees C until PCR. Two different methods of extraction of DNA were compared: a standard procedure (ST), using a normal extraction by phenol-chloroform, isoamyl alcohol and final precipitation in absolute ethanol and a direct procedure (DT), using a commercial kit (Qiaquik-Qiagen mini blood). A pair of bovine satellite primers and two pairs of different bovine Y-chromosome-specific primers (BRY4.a and BRY.1) were used in the PCR assay on embryos and on whole blood samples collected from male and female adult buffaloes, used as control. The trial was carried out on 359 embryos (193 for ST and 166 for DT). When DNA samples from blood were amplified, the sex determined by PCR always corresponded to the anatomical sex. Embryo sexing was not possible in two embryos in ST and one embryo in DT. Both extraction protocols recovered sufficient quantities of target DNA at all developmental stages, but the time required for the ST (24 h) limits its use in embryo sexing and supports the use of commercial extraction kits (5 h). 相似文献