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981.
Protein-DNA interactions in vivo upstream of a cell cycle-regulated human H4 histone gene 总被引:23,自引:0,他引:23
Cell cycle-dependent histone genes are transcribed at a basal level throughout the cell cycle, with a three- to fivefold increase during early S phase. Protein-DNA interactions in the 5' promoter region of a cell cycle-regulated human H4 histone gene have been analyzed at single-nucleotide resolution in vivo. This region contains two sites, with four potential protein-binding domains, at which the DNA is protected from reaction with dimethyl sulfate in cells and from digestion with deoxyribonuclease I in nuclei. These protein-DNA interactions persist during all phases of the cell cycle and dissociate with 0.16 to 0.2M sodium chloride. 相似文献
982.
U Johannsen 《Archiv fuer experimentelle veterinaermedizin》1973,27(3):449-479
983.
Bartels T Krautwald-Junghanns ME Portmann S Gille U Brinkmeier J Kummerfeld N 《Veterinary pathology》2002,39(3):396-399
Four birds in a flock of 125 purebred Crested ducks (Anas platyrhynchos f. dom.) had cerebellar signs of unknown etiology. They had radiographically evident perforations of various sizes in the parieto-occipital calvaria. Gross necropsy of euthanatized ducks revealed yellow intracranial masses in the brain of each. Histologically, these masses were intracranial lipomas consisting of univacuolated fatty tissue separated into lobules by strands of connective tissue. The masses had caused serious deformation of the rostral part of the cerebellum, leading to a nearly complete flattening of cerebellar folia, and were interpreted as the cause for the central nervous clinical signs observed. These intracranial lipomas were similar to those previously reported in other animals and humans. 相似文献
984.
985.
986.
The present research was undertaken to explor the possibility of arbuscular mycorrhizal(AM) association with Asteraceae plants in the arid lands of Saudi Arabia(Al-Ghat, Buraydah, Thumamah and Huraymila). AM fungal colonization in the roots, spore numbers in the rhizosphere soil, fungal species diversity and correlation between AM properties and soil properties were determined. The highest colonization was in Conyza bonariensis(65%) from Al-Ghat, Anthemis cotula(52%) from Buraydah and C. bonariensis(53%) from Thumamah. The lowest was in Vernonia schimperi(41%) from Al-Ghat, Pulicaria undulata(25%) from Buraydah, Acanthospermum hispidum(34%) from Thumamah, Asteriscus graveolens(22%) and V. schimperi(22%) from Huraymila. Vesicular and arbuscular colonization were also presented in all plant species examined. The number of spores were 112–207 in Al-Ghat, 113–133 in Buraydah, 87–148 in Thumamah and 107–158 in Huraymila. Funneliformis mosseae, Glomus etunicatum, G. fasciculatum and G. aggregatum were identified. Relative frequency of AM fungal species varied widely and was irrespective of location and plant species. Diversity index varied with the rhizosphere soils of different plant species at various locations. Soil properties varied with locations and no distinct correlations were observed among the soil properties, root colonization and the number of spores. The results of the present study specified the association of AM fungi in different plants of Asteraceae and its significance in the ecological functioning of annual plants in the punitive environments of the rangelands in Saudi Arabia. 相似文献
987.
U. Carlsson-Granér B. E. Giles P. H. Thrall 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(3):499-511
We use data from species of the anther-smut fungi and the host plants Lychnis alpina and Silene dioica to show that spatial structuring at different scales can influence patterns of disease and host resistance. Patterns of disease and host resistance were surveyed in an archipelago subject to land-uplift where populations of S. dioica constitute an age-structured metapopulation, and in three contrasting areas within the mainland range of L. alpina, where population distributions range from continuous, through patchy but spatially connected to highly isolated demes. In S. dioica, disease levels depend on the age, size and density of local patches and populations. Disease is most predictably found in larger dense host patches and populations of intermediate age, and more frequently goes extinct in small old populations. The rate of local disease spread is affected by the level of host resistance; S. dioica populations showing an increase in disease over time are more susceptible than populations where the disease has remained at low levels. Among-population variation in resistance is driven by founding events and populations remain differentiated due to limited gene flow between islands. As observed in the L. alpina system, when populations are more connected, a greater fraction of populations have disease present. Results from a simulation model argue that, while increased dispersal in connected systems can increase disease spread, it may also favour selection of host resistance which ultimately reduces disease levels within populations. This could explain the observed lower disease prevalence in L. alpina in regions where populations are more continuous. 相似文献
988.
K. U. Sorenmo V. M. Kristiansen M. A. Cofone F. S. Shofer A.‐M. Breen M. Langeland C. M. Mongil A. M. Grondahl J. Teige M. H. Goldschmidt 《Veterinary and comparative oncology》2009,7(3):162-172
This study describes the clinical and histopathological findings in dogs with mammary gland tumours, and compares the histopathological and clinical evidence consistent with progression from benign to malignant to human breast cancer epidemiology. Clinical and histopathological data on 90 female dogs with 236 tumours was included. Dogs with malignant tumours were significantly older than dogs with benign tumours (9.5 versus 8.5 years), P = 0.009. Malignant tumours were significantly larger than benign tumours (4.7 versus 2.1 cm), P = 0.0002. Sixty‐six percent had more than one tumour, and evidence of histological progression was noted with increasing tumour size. Dogs with malignant tumours were significantly more likely to develop new primary tumours than dogs with benign tumours, P = 0.015. These findings suggest that canine mammary tumours progress from benign to malignant; malignant tumours may be the end stage of a histological continuum with clinical and histopathological similarities to human breast carcinogenesis. 相似文献
989.
990.
Gabrielle R. Carter J. Catherine Scott-Moncrieff Andrew U. Luescher George Moore 《Journal of Veterinary Behavior: Clinical Applications and Research》2009,4(6):230-236
The aim of this case controlled study was to determine whether dogs with behavioral problems have evidence of abnormal thyroid function on routine screening tests for hypothyroidism. The hypothesis of the study was that thyroid function, as assessed by serum total thyroxine (TT4) and serum thyroid stimulating hormone (thyrotropin) (TSH) concentrations, is normal in most dogs with behavioral problems. Concentrations of TT4 and TSH in 39 dogs with behavior problems presenting to a veterinary behavior referral clinic (abnormal behavior group), were compared with TT4 and TSH concentrations in 39 healthy control dogs without behavior problems presenting to 5 community veterinary practices (control group). Dogs in the control group were matched for age and breed with the abnormal behavior group. Dogs with behavioral problems had higher TT4 concentrations than dogs without behavioral problems (t-test: t = 2.77, N = 39, P = 0.009), however none of the TT4 values were outside the reference range. There was no significant difference in TSH concentration between the 2 groups. Two dogs with behavior problems and 1 dog without behavior problems had results suggestive of hypothyroidism. All other dogs were considered to be euthyroid. There was no evidence to support a diagnosis of hypothyroidism in the majority of dogs with behavior problems in this study. The higher concentration of TT4 in dogs with behavior problems suggests, however, that alteration in thyroid hormone production or metabolism may occur in some dogs with behavior problems. Further studies that include additional indicators of thyroid status such as serum total triiodothyronine, serum, free thyroxine, and anti-thyroid antibody concentrations are necessary to further evaluate the significance of this finding. 相似文献