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771.
772.
The evolution of the number of genera in animal groups such as families, orders etc. is studied using paleontological data. The aim is to estimate birth-rates and mean existence-times of genera, which are here parameters of a birth-and-death process model. Two examples illustrate the method. 相似文献
773.
Comparative mapping in farm animals. 总被引:2,自引:0,他引:2
David W Burt 《Briefings in Functional Genomics and Prot》2002,1(2):159-168
This paper summarises the current status of comparative mapping in farm animals. For most of the major farm animal species, a wide range of genomic tools are now available to create high-resolution genetic and physical maps of the genome. For many farm animals, the use of radiation hybrid panels and sequence data from expressed sequence tag (EST) projects has accelerated the development of high-resolution comparative maps, with human--the model species for farm animals. These tools and comparative maps are being used to map and identify the genes at the loci for simple and complex traits. The development of detailed physical maps in farm animals based on radiation hybrid panels and bacterial artificial chromosome (BAC) contigs provides a direct link between the 'information-poor' maps of farm animals and the 'information-rich' genomes of human and other model organisms. 相似文献
774.
Alfredo D. Cuarn 《Zoo biology》2005,24(2):115-124
The role of zoos in conservation has evolved. Additional roles that zoos can play in conservation include monitoring live wildlife use (one of the main threats for many species). Zoos in many parts of the world are offered animals by the public and are required to receive animals confiscated by the authorities. By quantifying these animals, zoos can monitor live wildlife use rates and trends and obtain relevant information on the environment of a region which can assist in situ conservation management. Zoos are sometimes forced to receive unwanted animals from the public or the authorities. Receiving these animals is a burden for zoos. Agreements between zoos and governments are important to take care of these animals and to optimize the use of conservation resources. It is not possible or desirable to maintain all donated and seized animals. The International Union for Conservation of Nature and Natural Resources provides useful guidelines on what to do with them. In all cases, species conservation should take precedence over individual animal welfare. These issues are illustrated with data collected at Zoológico Regional Miguel Alvarez del Toro (ZOOMAT) in Chiapas, southern Mexico. Zoo Biol 24:115–124, 2005. © 2005 Wiley‐Liss, Inc. 相似文献
775.
Cheryl A. Logan 《Journal of the history of biology》2001,34(2):287-314
In America by the 1930s, albino rats had become a kind of generic standard in research on physiology and behavior that de-emphasized
diversity across species. However, prior to about 1915, the early work of many of the pioneer rat researchers in America and
in central Europe reflected a strong interest in species differences and a deep regard for diversity. These scientists sought
broad, often medical, generality, but their quest for generality using a standard animal did not entail a de-emphasis of organic
diversity. They chose white rats as test animals for two primary reasons. First, rats develop very slowly. They therefore
made features of physiological, neural and psychological development accessible to the experimental method at a time when
its application to the phenomena of development remained controversial. Secondly, rats were thought to have unusually strong
sex drives. For this reason they became central to the experimental study of sexuality and, in the work of the reproductive
physiologist Eugen Steinach, sexual development. Connections among three research institutes that stressed experimental approaches
to the study of brain and development demonstrate the importance of the rat's institutional role. As the emphasis on experimentation
in the study of development grew, two of these institutes bred rats to provide uniform materials. Eventually, however, their
reasons for selecting rats were lost; and the ready availability of a uniform test animal led to a shift in scientists' presumptions
about diversity, as the standard rat became a tool for assuring generality.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
776.
777.
The synuclein family and particularly α-synuclein takes a central part in aetiology and pathogenesis of Parkinson’s disease—one of the most common human neurodegenerative diseases. The pathological changes in certain other neurodegenerative diseases are also linked to changes in the metabolism and function of α-synuclein, hence comprising a new group of diseases—synucleinopathies. The molecular and cellular mechanisms that are involved in the development of neurodegeneration in synucleinopathies are still largely unknown. As a result, the therapeutic approaches to the treatment of synucleinopathies are inadequately tampered. The development of models of neurodegenerative process in laboratory animals plays a crucial role in the study of these molecular mechanisms. Recently a special emphasis was placed on transgenic animal models with modified expression of genes, whose mutations are associated with inherited forms of human neurodegenerative diseases. The current review is devoted to the analysis of different models of synucleinopathies as a result of genetic modifications of α-synuclein expression. 相似文献
778.
Catherine A. Lindell 《Restoration Ecology》2008,16(2):197-203
Animals are key members of ecosystems, contributing to processes like pollination, seed dispersal, and herbivory. Incorporating measures of animal behavior into evaluations of restoration success will provide critical information that is not available from animal species composition and richness estimates derived from the documentation of species presence and absence. Behavioral studies will (1) allow comparisons of the habitat quality of target and reference sites based on behaviors that have fitness consequences for organisms; (2) provide valuable information about reasons for differences in habitat quality; (3) identify critical resources that make a site suitable or not for particular species; and/or (4) provide information on the mechanisms through which species contribute to ecosystem functions. When resources for the evaluation of restoration success are available, practitioners should carefully consider the costs and benefits of the different variables they could quantify. In some cases, it may be more important to compare the behavior of one or a few critical animal species that contribute to ecosystem function rather than try to document the presence or absence of all species. 相似文献