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81.
82.
A new arbovirus from Aedes albopictus, an Asian mosquito established in the United States 总被引:3,自引:0,他引:3
D B Francy N Karabatsos D M Wesson C G Moore J S Lazuick M L Niebylski T F Tsai G B Craig 《Science (New York, N.Y.)》1990,250(4988):1738-1740
Ten strains of a new arbovirus belonging to the Bunyamwera group (Bunyaviridae) were recovered from field-collected Aedes albopictus mosquitoes in Potosi, Missouri. This evidence indicates that this species may serve as an arbovirus vector in the United States. The urban-suburban distribution, aggressive biting behavior, and broad viral susceptibility of Ae. albopictus may lead to the transmission of viruses of known public health importance and perhaps of viruses hitherto not transmitted to humans because of the feeding pattern of their usual vectors. 相似文献
83.
Oncogenicity by methyl methanesulfonate in male RF mice 总被引:1,自引:0,他引:1
The incidences of lung tumors and thymic lymphomas were increased in young adult male RF mice receiving 30 milligrams of methyl meth anesulfonate per kilogram of body weight daily in the drinking water throughout life. Differences in oncogenicity between treatment with methyl methanesulfonate and with dimethylnitrosamine or diethylnitrosamine suggest a qualitative difference between the site (or sites) of alkylation by methyl methanesulfonate and by dimethylnitrosamine or diethylnitrosamine within the nucleic acids. 相似文献
84.
Inversion of the measurements obtained by the infrared limb scanner on the Nimbus 6 satellite has demonstrated that the stratospheric and mesospheric temperatures and ozone concentrations may be obtained remotely from space with accuracy and precision comparable to in situ methods. Such global data have many applications in middle atmospheric research and operational temperature sounding. 相似文献
85.
Nicotine in breast fluid of nonlactating women 总被引:2,自引:0,他引:2
N L Petrakis L D Gruenke T C Beelen N Castagnoli J C Craig 《Science (New York, N.Y.)》1978,199(4326):303-305
Using a combination of gas chromatography, mass spectrometry, and selected ion recording techniques, we have identified nicotine and its major metabolite, continine, in the breast fluid of nonlactating women smokers. As little as 25 picograms could be measured by using the deuterated variants, [5',5'-2H]nicotine and [3,3-2H]cotinine, both as internal standards and as carriers in an inverse isotope dilution method. 相似文献
86.
Multilineage potential of adult human mesenchymal stem cells 总被引:7,自引:0,他引:7
Pittenger MF Mackay AM Beck SC Jaiswal RK Douglas R Mosca JD Moorman MA Simonetti DW Craig S Marshak DR 《Science (New York, N.Y.)》1999,284(5411):143-147
Human mesenchymal stem cells are thought to be multipotent cells, which are present in adult marrow, that can replicate as undifferentiated cells and that have the potential to differentiate to lineages of mesenchymal tissues, including bone, cartilage, fat, tendon, muscle, and marrow stroma. Cells that have the characteristics of human mesenchymal stem cells were isolated from marrow aspirates of volunteer donors. These cells displayed a stable phenotype and remained as a monolayer in vitro. These adult stem cells could be induced to differentiate exclusively into the adipocytic, chondrocytic, or osteocytic lineages. Individual stem cells were identified that, when expanded to colonies, retained their multilineage potential. 相似文献
87.
88.
Double-stranded RNA-mediated gene interference (RNAi) in Caenorhabditis elegans systemically inhibits gene expression throughout the organism. To investigate how gene-specific silencing information is transmitted between cells, we constructed a strain that permits visualization of systemic RNAi. We used this strain to identify systemic RNA interference-deficient (sid) loci required to spread gene-silencing information between tissues but not to initiate or maintain an RNAi response. One of these loci, sid-1, encodes a conserved protein with predicted transmembrane domains. SID-1 is expressed in cells sensitive to RNAi, is localized to the cell periphery, and is required cell-autonomously for systemic RNAi. 相似文献
89.
Rational design of peptide-based HIV proteinase inhibitors 总被引:48,自引:0,他引:48
N A Roberts J A Martin D Kinchington A V Broadhurst J C Craig I B Duncan S A Galpin B K Handa J Kay A Kr?hn 《Science (New York, N.Y.)》1990,248(4953):358-361
A series of peptide derivatives based on the transition-state mimetic concept has been designed that inhibit the proteinase from the human immunodeficiency virus (HIV). The more active compounds inhibit both HIV-1 and HIV-2 proteinases in the nanomolar range with little effect at 10 micromolar against the structurally related human aspartic proteinases. Proteolytic cleavage of the HIV-1 gag polyprotein (p55) to the viral structural protein p24 was inhibited in chronically infected CEM cells. Antiviral activity was observed in the nanomolar range (with one compound active below 10 nanomolar) in three different cell systems, as assessed by p24 antigen and syncytium formation. Cytotoxicity was not detected at 10 and 5 micromolar in C8166 and JM cells, respectively, indicating a high therapeutic index for this new class of HIV proteinase inhibitors. 相似文献
90.
Erlandson JM Rick TC Braje TJ Casperson M Culleton B Fulfrost B Garcia T Guthrie DA Jew N Kennett DJ Moss ML Reeder L Skinner C Watts J Willis L 《Science (New York, N.Y.)》2011,331(6021):1181-1185
Three archaeological sites on California's Channel Islands show that Paleoindians relied heavily on marine resources. The Paleocoastal sites, dated between ~12,200 and 11,200 years ago, contain numerous stemmed projectile points and crescents associated with a variety of marine and aquatic faunal remains. At site CA-SRI-512 on Santa Rosa Island, Paleocoastal peoples used such tools to capture geese, cormorants, and other birds, along with marine mammals and finfish. At Cardwell Bluffs on San Miguel Island, Paleocoastal peoples collected local chert cobbles, worked them into bifaces and projectile points, and discarded thousands of marine shells. With bifacial technologies similar to those seen in Western Pluvial Lakes Tradition assemblages of western North America, the sites provide evidence for seafaring and island colonization by Paleoindians with a diversified maritime economy. 相似文献