全文获取类型
收费全文 | 450篇 |
免费 | 12篇 |
出版年
2022年 | 5篇 |
2021年 | 15篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 13篇 |
2014年 | 30篇 |
2013年 | 32篇 |
2012年 | 31篇 |
2011年 | 29篇 |
2010年 | 20篇 |
2009年 | 20篇 |
2008年 | 21篇 |
2007年 | 19篇 |
2006年 | 17篇 |
2005年 | 8篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有462条查询结果,搜索用时 15 毫秒
1.
2.
Shailesh Kumar Atma P. Dwivedi Vivek Kr. Kashyap A.K. Saxena A.K. Dwivedi Ranjana Srivastava Devi P. Sahu 《Bioorganic & medicinal chemistry letters》2013,23(8):2404-2407
Synthesis of a library of novel trans 6-methoxy-1,1-dimethyl-2-phenyl-3-aryl-2,3-dihydro-1H-inden-4-yloxy alkyl amines and their antimycobacterial activity against drug sensitive and multidrug resistant strains of Mycobacterium tuberculosis have been reported. All the new compounds in the series exhibited MIC between 1.56 and 6.25 μg/ml. Two compounds 1i and 1j with low MIC and low cytotoxicity showed significant reduction in CFU in infected mouse macrophages at 1× MIC concentration. The compound 1i inhibited the growth of M. tuberculosis in mice at 100 mg/kg dose with 1.35 log10 reduction of CFU in lungs tissue and was active against non-replicating Mycobacterium tuberculosis under anaerobic condition. 相似文献
3.
A K Srivastava C Pandey K P Dwivedi V K Singh 《Indian journal of biochemistry & biophysics》1989,26(3):199-200
QSAR studies have been performed on the homologues of 3-triazines, using molecular connectivity index and van der Waal volume as structural parameters. The regression analysis has shown good correlation between antitumour activity and the two structural parameters. 相似文献
4.
High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans 总被引:1,自引:0,他引:1
We compared male-reproductive-tract polypeptides of Drosophila melanogaster
and D. simulans by using two-dimensional gel electrophoresis. Approximately
64% of male-reproductive-tract polypeptides were identical between two
randomly chosen isofemale lines from these two species, compared with 83%
identity for third-instar imaginal wing-disc polypeptides. Qualitatively
similar differences were found between reproductive tracts and imaginal
discs when D. sechellia was compared with D. melanogaster and with D.
simulans. When genic polymorphism was taken into account, approximately 10%
of male- reproductive-tract polypeptides were apparently fixed for
different alleles between D. melanogaster and D. simulans; this proportion
is the same as that found for soluble enzymes by one-dimensional gel
electrophoresis. Strikingly, approximately 20% of male-reproductive- tract
polypeptides of either D. melanogaster or D. simulans had no detectable
homologue in the other species. We propose that proteins of the Drosophila
male reproductive tract may have diverged more extensively between species
than have other types of proteins and that much of this divergence may
involve large changes in levels of polypeptide expression.
相似文献
5.
6.
7.
Different preparations of chromatin isolated from mycelia of Neurospora crassa were analyzed for DNA-associated RNA and proteins. The UV absorption spectra, the ultrastructure of chromatin, and the amino acid composition of the acid-extractable proteins were studied. The protein:DNA ratios range from 1.5 to 2.8; the RNA:DNA ratios range from 0.5 to 1.24. UV absorption shows a macimum at 259 mµ and a minimum at 238–239 mµ. The E280/E260 ranges from 0.59 to 0.70. Electron microscopy reveals a fibrous structure with individual fibers of 120–150 A average diameter. Attempts were made to study the protein by polyacrylamide gel electrophoresis and amino acid analysis. The results indicate that Neurospora chromatin does not contain basic proteins comparable to calf thymus histone. The ratios of basic to acidic amino acids range from 0.93 to 1.19. On electrophoresis, no bands are seen whose positions correspond to those of histones. Staining for basic proteins with fast green or eosin Y at pH 8.2 also shows a negative reaction, suggesting the absence of histones. 相似文献
8.
9.
Essential oils isolated from leaves and seeds of seven umbelliferous plants were tested against the growth ofAspergillus flavus. Those from seeds ofTrachyspermum ammi, Cuminum cyminum, Carum carvi, Daucus carota and from leaves ofAnethum graveolens exhibited antifungal activity against the test fungus. Amongst these, oil from seeds ofTrachyspermum ammi was most toxic. Its minimum inhibitory concentration was 300 ppm, at which it exhibited fungistatic but not phytotoxic properties, when tested at 200, 300 and 400 ppm. The fungitoxic potency ofTrachyspermum seed oil remained unchanged after a long storage period and at high inoculum density of the test fungus. The oil was thermostable and was more efficaceous than the fungicides Agrosan G.N., Benlate, Ceresan, Dithane M-45 and Thiovit commonly used for the control of plant diseases. 相似文献
10.
RS Fisher 《The Journal of general physiology》1977,69(5):571-604
When the outer surface of short-circuited frog skin was penetrated with microelectrodes, stable negative potentials that averaged near -100 mV were recorded consistently, confirming the results of Nagel (W. Nagel. 1975. Abstracts of the 5th International Biophysics Congress, Copenhagen. P-147.). The appearance of these stable potentials, V(O), concurrent with the observations that (a) a high resistance outer barrier R(O) accounting for approximately 75 percent or more of the transcellular resistance of control skins had been penetrated and that (b) 10(-5) M amiloride and reduced [Na] outside caused the values of V(O) to increase towards means value near -130 mV while the values of percent R(O) increased to more than 90 percent. It was of relationships were the same as the values of E(1) observed in studies of the current-voltage relationships were the same as the values of E’(1) defined as the values of voltage at the inner barrier when the V(O) of the outer barrier was reduced to zero by voltage clamping of the skins. Accordingly, these data are interpreted to mean that the values of E(1), approximately 130 mV, represent the E(Na) of the sodium pump at the inner barrier. 2,4-DNP was observed to decrease the values of transepithelial voltage less than E(1) the V(O) was negative. These data can be interpreted with a simple electrical equivalent circuit of the active sodium transport pathway of the frog skin that includes the idea that the outer membrane behaves as an electrical rectifier for ion transport. 相似文献