全文获取类型
收费全文 | 256篇 |
免费 | 15篇 |
专业分类
271篇 |
出版年
2022年 | 5篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 12篇 |
2014年 | 10篇 |
2013年 | 13篇 |
2012年 | 18篇 |
2011年 | 21篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 5篇 |
2003年 | 10篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1996年 | 1篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 10篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1974年 | 5篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 6篇 |
1967年 | 4篇 |
1966年 | 2篇 |
1965年 | 4篇 |
1964年 | 5篇 |
1963年 | 1篇 |
排序方式: 共有271条查询结果,搜索用时 15 毫秒
101.
102.
The cytotoxic necrotizing factor 1 (CNF1) from Escherichia coli activates members of the Rho family by deamidation of glutamine 61/63. Because this amino acid is crucial for GTP hydrolysis, deamidation of glutamine 61/63 results in constitutively active Rho proteins. Recently, it was shown that the level of CNF1-activated Rac is rapidly diminished in CNF1-treated cells by proteolytic degradation. Here, we studied the requirements for CNF1-induced Rac degradation. By overexpressing His-tagged activated Rac mutants we show that constitutive activation is necessary for degradation of Rac. However, permanent activation is not sufficient for degradation, because Rac that is constitutively activated by transamidation at glutamine 61 by the Bordetella dermonecrotic toxin is not degraded. Overexpression of His-tagged Rac mutants deficient in interaction with GTPase-activating protein (Rac(N92D) and Rac(Y64H)) and guanosine nucleotide dissociation inhibitor (Rac(H103E)) were degraded after activation by CNF1, whereas Rac(Y40C), which is not able to interact with CRIB domain effectors or plenty of SH3, was not degraded. Isoprenylation and the presence of a putative mitotic destruction box are essential for CNF-induced degradation. In contrast to Rac1, Rac2, and Rac3 were not degraded following constitutive activation by CNF1. Using site-directed mutagenesis, we defined the polybasic region and amino acids 90, 107, 147, and 151 as responsible for isotype-specific degradation. 相似文献
103.
Majstorov V Pop Gjorceva D Vaskova O Vavlukis M Peovska I Maksimović J 《Prilozi / Makedonska akademija na naukite i umetnostite, Oddelenie za biolo?ki i medicinski nauki = Contributions / Macedonian Academy of Sciences and Arts, Section of Biological and Medical Sciences》2005,26(1):93-102
There are some specifics in the presentation of coronary artery disease (CAD) in women compared with men that may cause diagnostic pitfalls. The accuracy of noninvasive diagnostic testing in women tends to be lower than that in men. Stress myocardial perfusion imaging with 99m-Tc sestamibi gated SPECT is an accurate technique for detecting CAD. Only a few studies have compared dipyridamole stress imaging according to gender. The aim of the study was to compare the diagnostic value of dipyridamole myocardial perfusion imaging with 99m-Tc sestamibi gated SPECT in detecting CAD among patients of both sexes. We studied 62 consecutive patients (38 men, 24 women) using 99m-Tc sestamibi gated SPECT and dipyridamole stress to detect CAD. All the patients also underwent coronary angiography. Overall regional sensitivity was significantly lower in women compared with men (71.4% vs. 92.7%, p=0.039). There were no significant differences for detecting CAD in individual coronary arteries, although regional sensitivity in all three vascular territories was higher in men compared to women. The lowest sensitivity in women was found in the LAD territory (66.6%). Overall regional specificity in men and women was similar and did not reach statistical significance (88.7% vs. 94.7%). Significantly lower specificity in men was found only in the RCA territory (79.1%), compared with that in women (100%). Our results confirmed that there are certain gender differences in the diagnostic performance of dipyridamole stress myocardial perfusion imaging with 99-Tc sestamibi gated SPECT which are assigned to the characteristics of the female population. However, the diagnostic accuracy is also quite high in women, which makes this technique efficient enough in detecting CAD among this population. 相似文献
104.
105.
Zusammenfassung Bei 20 ausgewachsenen weiblichen Ratten mit verlängertem und unregelmässigem Oestruszyklus (13 ± 10 Tage) wurde nach 25 Tagen einer täglichen einstündigen Behandlung mit negativen Luftionen die Zykluslänge auf 6 ± 3 Tage reduziert.
The irregular and prolonged oestrus cycle of 13 ± 10 days in 20 adult female rats was reduced to 6 ± 3 days after an 1-hr daily treatment with small negative ions for a period of 25 days.
Resume 20 femelles de rats dont le cycle menstruel était irrégulier et prolongé (13 ± 10 jours) ont été exposées durant 25 jours à de l'air enrichi de petits ions négatifs et cela à raison de 1 heure par jour. Leur cycle en a été réduit à 6 ± 3 jours.相似文献
106.
Tetrathiafulvalene‐[2.2]paracyclophanes: Synthesis,crystal structures,and chiroptical properties 下载免费PDF全文
Cécile Mézière Magali Allain Cristina Oliveras‐Gonzalez Thomas Cauchy Nicolas Vanthuyne Laura G. Sarbu Lucian M. Birsa Flavia Pop Narcis Avarvari 《Chirality》2018,30(5):568-575
Two racemic tetrathiafulvalene‐[2.2]paracyclophane electron donors EDT‐TTF‐[2.2]paracyclophane 1 and (COOMe)2‐TTF‐[2.2]paracyclophane 2 have been synthesized via the phosphite mediated cross coupling strategy. Chiral HPLC allowed the optical resolution of the (RP) and (SP) enantiomers for both compounds. Solid‐state structures of (RP)‐ 1 and (rac)‐ 2 have been determined by single crystal X‐ray analysis. Intermolecular π‐π and S???S interactions are disclosed in the packing. Single crystal X‐ray analysis of (RP)‐ 1 combined with experimental and theoretical circular dichroism spectra allowed the assignment of the absolute configuration of the enantiomers of 1 and 2 . 相似文献
107.
A Pop?awski M My?liwiec J Soszka 《Polski tygodnik lekarski (Warsaw, Poland : 1960)》1990,45(40-41):810-813
Ultrafiltrates obtained from the patients with chronic uremia were chromatographically separated in the column filled with Sephadex A25. "Middle" molecular weight substances were localized mainly in a single peak. Dialysis decreased their contents. Determination of the fibrinolytic activity of each chromatographic fractions with caseinolytic and fibrinplate techniques has shown activating effect of the fractions 10-12. Dialysis decreased fibrinolytic activity statistically significantly. 相似文献
108.
109.
The effects of pulsed, high frequency radio waves on rat liver (ultrastructural and biomedical observations) 总被引:1,自引:0,他引:1
L Pop M Muresan S Comorosan L Paslaru 《Physiological chemistry and physics and medical NMR》1989,21(1):45-55
The effects of a high frequency electro-magnetic field, generated by a Diapulse instrument (Diapulse Corporation of America) on rat liver has been investigated. Ultrastructural aspects are described and quantitative determinations of mitochondrial enzymes MAO, CyT-Ox, MDH, SDH and ATP-ase recorded. The standard therapeutic parameters generally used with the Diapulse instrument in medicine were found to induce a stimulation effect at the investigated level, without apparent degenerative modifications. A concordance between the qualitative ultrastructural data and quantitative subcellular enzymic determinations has been observed. 相似文献
110.
Mathieu Almeida Agnès Hébert Anne-Laure Abraham Simon Rasmussen Christophe Monnet Nicolas Pons Céline Delbès Valentin Loux Jean-Michel Batto Pierre Leonard Sean Kennedy Stanislas Dusko Ehrlich Mihai Pop Marie-Christine Montel Fran?oise Irlinger Pierre Renault 《BMC genomics》2014,15(1)