全文获取类型
收费全文 | 598篇 |
免费 | 42篇 |
出版年
2022年 | 4篇 |
2021年 | 6篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 18篇 |
2015年 | 37篇 |
2014年 | 32篇 |
2013年 | 36篇 |
2012年 | 37篇 |
2011年 | 20篇 |
2010年 | 25篇 |
2009年 | 24篇 |
2008年 | 23篇 |
2007年 | 25篇 |
2006年 | 29篇 |
2005年 | 22篇 |
2004年 | 19篇 |
2003年 | 19篇 |
2002年 | 7篇 |
2001年 | 17篇 |
2000年 | 17篇 |
1999年 | 18篇 |
1998年 | 15篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 9篇 |
1973年 | 4篇 |
1972年 | 10篇 |
1971年 | 3篇 |
1969年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有640条查询结果,搜索用时 15 毫秒
81.
Bergh A Gradén H Pera NP Olsson T Nilsson UJ Kann N 《Carbohydrate research》2008,343(10-11):1808-1813
Cationic iron carbonyl cyclohexadiene complexes were employed in the derivatization of the 3-OH position of unprotected and protected methyl beta-D-galactopyranosides using two different approaches, giving access to galactopyranosides with an aromatic or cyclohexadienoic functionality in this position. 相似文献
82.
The effect of food deprivation on ova transport, hormonal profiles and metabolic changes was studied in 20 crossbred multiparous
sows during their second oestrus after weaning. To determine the time of ovulation, transrectal ultrasonographic examination
was performed. The sows were divided into 2 groups, one control group (C-group), which was fed according to Swedish standards,
and one experimental group (E-group). The E-group sows were deprived of food from the first morning meal after ovulation until
slaughter. Blood samples were collected every second hour from about 12 h before expected ovulation in the second oestrus
after weaning until slaughter and were analysed for progesterone, prostaglandin F2α-metabolite, insulin, glucose, free fatty acids and triglycerides. All sows were slaughtered approximately 48 h after ovulation
and the genital tract was recovered. The isthmic part of the oviduct was divided into 3 equally long segments and flushed
separately with phosphate buffered saline (PBS). Uterine horns were also flushed with PBS. A significantly greater number
of ova were found in the first and second part of the isthmus in the E-group (p = 0.05) while in the C-group most of the ova
were found in the third part of the isthmus or the uterus (p = 0.01). The level of prostaglandin F2α-metabolite was significantly higher in the E-group compared with the C-group. The concentration of progesterone increased
in both groups after ovulation but there were no significant differences between the groups. The other blood parameters showed
that the food-deprived sows were in a catabolic state. The 48 h period of fasting results, directly or indirectly in an delayed
ova transport, which may be due to a delayed relaxation in the smooth circular muscle layer of the isthmus. 相似文献
83.
Martinus AM van Boekel Erik R Vossenaar Frank HJ van den Hoogen Walther J van Venrooij 《Arthritis research & therapy》2001,3(2):1-7
This review focuses on the mechanisms of stress response in the synovial tissue of rheumatoid arthritis. The major stress factors, such as heat stress, shear stress, proinflammatory cytokines and oxidative stress, are discussed and reviewed, focusing on their potential to induce a stress response in the synovial tissue. Several pathways of stress signalling molecules are found to be activated in the synovial membrane of rheumatoid arthritis; of these the most important examples are heat shock proteins, mitogen-activated protein kinases, stress-activated protein kinases and molecules involved in the oxidative stress pathways. The expression of these pathways in vitro and in vivo as well as the consequences of stress signalling in the rheumatoid synovium are discussed. Stress signalling is part of a cellular response to potentially harmful stimuli and thus is essentially involved in the process of synovitis. Stress signalling pathways are therefore new and promising targets of future anti-rheumatic therapies. 相似文献
84.
This investigation examined the exposure of Egyptian infants to Aflatoxin M1 (AfM1) and of lactating mothers to Aflatoxin B1, using AfM1 in human milk as a biomarker for exposure to AfB1. The presence of ochratoxin A (OA) in human milk was also investigated to determine the levels of infants exposure to OA
from human milk. The results indicated that AfM1 was found in 66 (55 %) of 120 human milk samples with a mean of 0.3 ± 0.53 ng/mL (range 0.02 to 2.09 ng/mL). OA was found
in 43 (35.8 %) of 120 human milk samples with a mean of 21.1 ± 13.7 ng/mL (range 5.07 to 45.01 ng/mL), which will cause a
daily intake of OA from human milk exceeding the suggested tolerable dose of 5 ng/kg-1 of OA body weight. On the other side AfM1 was found in 25 % of blood samples (5 out of 20 samples), at a mean of 1.18 ng/mL, but it was detected only in one urine
sample (1 out of 20 samples). OA was detected only in 2 out of 13 blood samples (15.4 %) with an average 3.67 ng/mL. Whereas
OA was not detected in all analyzed urine samples. 相似文献
85.
86.
Synthesis of novel paclitaxel prodrugs designed for bioreductive activation in hypoxic tumour tissue. 总被引:2,自引:0,他引:2
Eric W P Damen Tapio J Nevalainen Toine J M van den Bergh Franciscus M H de Groot Hans W Scheeren 《Bioorganic & medicinal chemistry》2002,10(1):71-77
The syntheses and preliminary evaluation of the first potential bioreductive paclitaxel prodrugs are described. These prodrugs were designed as potential candidates in more selective chemotherapy by targeting hypoxic tumour tissue. Aromatic nitro and azide groups were used as the bioreductive trigger. Generation of paclitaxel occurs after reduction and subsequent 1,6-elimination or 1,8-elimination. All prodrugs are stable in buffer and indeed give paclitaxel after chemical reduction of the aromatic nitro or azide functionality. In aerobic cytotoxicity assays several prodrugs exhibit diminished cytotoxicity. These compounds are interesting candidates for further biological evaluation. 相似文献
87.
Yannick Willemen Johan M. J. Van den Bergh Eva Lion Sébastien Anguille Vicky A. E. Roelandts Heleen H. Van Acker Steven D. I. Heynderickx Barbara M. H. Stein Marc Peeters Carl G. Figdor Viggo F. I. Van Tendeloo I. Jolanda de Vries Gosse J. Adema Zwi N. Berneman Evelien L. J. Smits 《Cancer immunology, immunotherapy : CII》2015,64(7):831-842
88.
Belinda Strydom Jacobus J. Bergh Jacobus P. Petzer 《Bioorganic & medicinal chemistry letters》2013,23(5):1269-1273
Based on recent reports that the small molecules, isatin and phthalimide, are suitable scaffolds for the design of high potency monoamine oxidase (MAO) inhibitors, the present study examines the MAO inhibitory properties of a series of phthalide [2-benzofuran-1(3H)-one] analogues. Phthalide is structurally related to isatin and phthalimide and it is demonstrated here that substitution at C6 of the phthalide moiety yields compounds endowed with high binding affinities to both human MAO isoforms. Among the nineteen homologues evaluated, the lowest IC50 values recorded for the inhibition of MAO-A and -B were 0.096 and 0.0014 μM, respectively. In most instances, C6-substituted phthalides exhibit MAO-B specific inhibition. Among a series of 6-benzyloxyphthalides bearing substituents on the para position of the phenyl ring the general order of potency was CF3 > I > Br > Cl > F > CH3 > H. The results also show that the binding modes of representative phthalides are reversible and competitive at both MAO isoforms. Based on these data, C6-substituted phthalides may serve as leads for the development of therapies for neurodegenerative disorders such as Parkinson’s disease. 相似文献
89.