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1.
2.
The uvsC gene of Aspergillus nidulans is a homolog of the RAD51 gene of Saccharomyces cerevisiae. However, with respect to its effects on UV mutagenesis, it differs from the yeast gene, since it seems to be required for
UV mutagenesis; however, this conclusion is based only on data from resting conidia. To further clarify the functional role
of the uvsC gene, we tested the UV mutability of strains bearing a uvsC mutation in resting as well as in germinating conidia, by the p-fluoro-phenyl-alanine resistance test. We also evaluated the mutability of the uvsE mutant which belongs to the same epistatic group. Our results show that the uvsC and uvsE genes do not have a significant role in the mutagenic UV-repair pathway.
Received: 20 January 1998 / Accepted: 22 April 1998 相似文献
3.
The Mg2+ ion-assisted activation mechanism of the active site Tyr8 of a human hematopoietic prostaglandin D2 synthase (H-PGDS) was studied by ultraviolet resonance Raman (UVRR) spectroscopy. Addition of Mg2+ to the native H-PGDS at pH 8.0 resulted in the Y8a Raman band of Tyr8 shifting from 1615 cm−1 to 1600 cm−1. This large shift to lower energy of the tyrosine Y8a vibrational mode is caused by the deprotonation of the tyrosine phenol group promoted by binding of Mg2+. Upon subsequent addition of glutathione (GSH), the Mg2+/H-PGDS solution showed the Tyr8 Raman band shifted to 1611 cm−1, which is 11 cm−1 higher than the frequency of the Mg2+ complex of H-PGDS, but 4 cm−1 lower than the Mg2+ free enzyme. These UVRR observations suggest that the deprotonated Tyr8 in the presence of Mg2+ is re-protonated by the abstraction of H+ from the thiol group of GSH, and that the re-protonated Tyr8 species forms a hydrogen bond with the thiolate anion of GSH. Density functional theory calculations on several model complexes of p-cresol were also performed, which suggested that the pKa and vibrational frequencies of the Tyr8 phenol group are affected by the degree and structure of hydration of the Tyr8 residue. 相似文献
4.
5.
《Current biology : CB》2020,30(11):2051-2067.e5
6.
Monocotyledons of 104 species in 52 families were divided into two groups depending on the UV fluorescence behaviour of their cell walls. The unlignified cell walls of the first group, fluoresced blue, which changed to green with increased intensity after treatment with NH3 due to the presence of bound ferulic acid. The isolated cell walls of members of the first group were shown to contain bound ferulic, p-coumaric and diferulic acids. These acids were absent from cell walls of the second group. The first group contained families of the Commelinidae of Cronquist, the Palmae (part of the Arecidae), and the Philydraceae, Pontederiaceae, and Haemodoraceae (all part of Liliidae). The other families of the latter two subclasses and those of the Alismatidae belonged to the second group. 相似文献
7.
Ian M. Morrison 《Phytochemistry》1974,13(7):1161-1165
Lignin-carbohydrate and lignin-hemicellulose complexes were extracted sequentially from four varieties of Lolium perenne which had previously been 相似文献
8.
Measurement of the UV spectra in 12·7 M H2SO4 at 30° and 70° provides a simple, quantitative and specific method for the identification of variously substituted, naturally occurring plant indoles in μg quantities. 相似文献
9.
Gerald H. Jacobs 《International journal of primatology》2007,28(4):729-759
The visual worlds of most primates are rich with potential color signals, and many representatives of the order have evolved
the biological mechanisms that allow them to exploit these sources of information. Unlike the catarrhines, platyrrhines typically
have sex-linked polymorphic color vision that provides individuals with any of several distinct types of color vision, including
both trichromatic and dichromatic variants. In recent years, this polymorphism has been the target of an expanding range of
research efforts. As a result, researchers now reasonably understand the proximate biology underlying the polymorphisms, and
a number of ideas have emerged as to their evolution. Progress has also been made in illuminating how color vision capacities
may be related to the particular visual tasks that New World monkeys face. 相似文献
10.
We describe here simple techniques for increasing the frequency of UV-induced mutations in a DNA fragment cloned in plasmid pBR322. Irradiation of both the host and the plasmid DNA before transformation is necessary to produce new mutations in the plasmid DNA, presumably because the UV-damaged pBR322 replicon cannot efficiently induce the error-prone repair pathway of Escherichia coli. In contrast, U V irradiation of the plasmid DNA alone before transformation primarily causes the transfer of preexisting mutations from the host chromosome to homologous DNA present in the plasmid. The only other kind of mutants obtained were large deletions of the plasmid DNA. Two chromosomal mutations from the host galK gene and one from the lacZ gene have been transferred to the plasmid by UV irradiation of the plasmid DNA alone. The technique can thus be of general use. 相似文献