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991.
Abstract. Using the unusually well-documented butterfly fauna of Davis, Yolo County, California, it is shown that the mainly native species commonly observed in gardens breed mostly or entirely on alien plants, especially naturalized weeds. Over 40% of the fauna has no known native hosts in the urban–suburban environment. Were certain alien weeds to be eradicated or their abundance greatly reduced, the urban-suburban butterfly fauna would disappear. This might be regarded as an unfortunate, and perhaps intolerable, side-effect of such programs. 相似文献
992.
Pollination and phenology of flowers in the canopy of two contrasting rain forest types in Amazonia,Colombia 总被引:3,自引:0,他引:3
The main objective of this investigation was to study the pollination characteristics of two types of Amazonian rain forest at plant community level. Seasonally inundated forest was compared with upland (tierra firme) forest. The study focused on plant species in the canopy. The pollination spectra show that in both forests most canopy trees and lianas are pollinated by small bees, large bees, butterflies or by small, relatively unspecialized insects. In the upland forest small bees are the most important pollinators (32% of all species of trees and lianas are pollinated by them), whereas large bees are predominant in the floodplain (22%). Other pollinators, like hummingbirds, bats, moths, and beetles are less common (>10%), but always somewhat more important in the flood plain than in the upland forest. Bees are the most common pollinators of epiphytes. In the flood plain forest, flies are also important as epiphyte pollinators (19%), whereas in the upland forest hummingbirds pollinate more epiphytes. The phenological patterns are quite similar in both the upland and the flood plain. We found a peak in flowering in the transition period between the wet and the dry season. Flowering activity was lowest during the wet season. Differentiation in sexual systems was correlated with life form. Dioecy and monoecy were found mostly among tree species. Most species of all life forms though were hermaphroditic. No difference with respect to the relative importance of sexual systems was found between the two forest types. 相似文献
993.
Differences in Composition and Mucosal Adhesion of Bifidobacteria Isolated from Healthy Adults and Healthy Seniors 总被引:8,自引:0,他引:8
Fang He Arthur C. Ouwehand Erika Isolauri Masataka Hosoda Yoshimi Benno Seppo Salminen 《Current microbiology》2001,43(5):351-354
Fifty-one Bifidobacterium strains were isolated from the feces of healthy adults (30–40 years old) and seniors (older than 70 years of age). B. adolescentis, B. breve, B. infantis, and B. longum were isolated from the healthy adults and B. adolescentis and B. longum from elderly subjects. The tested bacteria bound, in vitro, to intestinal mucus in a strain dependent manner. The strains
isolated from healthy adults, and especially B. adolescentis, bound better to intestinal mucus than those isolated from seniors. These results indicate that the mucosal adhesive properties
of the human Bifidobacterium flora were reduced with the aging of the host. This shift to a Bifidobacterium flora with reduced adhesive abilities may explain the decrease in bifidobacteria levels in the intestinal microflora of aging
people.
Received: 7 February 2001 / Accepted: 3 April 2001 相似文献
994.
CYP2E1-dependent toxicity and oxidative stress in HepG2 cells 总被引:11,自引:0,他引:11
Arthur I. Cederbaum Defeng Wu Montserrat Mari Jingxiang Bai 《Free radical biology & medicine》2001,31(12):80-1543
995.
Arthur Bob Karnuah Hirohide Uenishi Sachiko Kiuchi Misaki Kojima Akira Onishi Hiroshi Yasue Tadayoshi Mitsuhashi 《Mammalian genome》2001,12(7):518-523
A swine resource family was constructed at the National Institute of Animal Industry, Japan, in order to determine the genetic
regions responsible for economically important traits, including fetus development. To identify genes expressed in the early
stage of embryo development, we cataloged and mapped genes expressed in a 28-day-old normal pig embryo. In this effort, we
have mapped 64 genes, which have map information in human genome onto a swine radiation hybrid (RH) map, IMpRH. These mappings
provided additional chromosomal homologies between swine and human to improve the comparative map between the two species.
The distribution of the genes assigned to swine chromosomes are as follows: 9 genes were assigned on SSC6; 6 genes each assigned
on SSC5 and SSC14; 5 genes each assigned on SSC3, SSC4, and SSC8; 4 genes each assigned on SSC1, SSC7, SSC9, and SSC15; 3
genes each assigned on SSC2, SSC13 and SSCX; and 1 gene each assigned on SSC10, SSC11, and SSC16. Moreover, the present findings
revealed 18 new chromosomal homologies between pig and human. Briefly, SSC3 regions were indicated to correspond with HSA1
and HSA10; SSC4 with HSA6; SSC5 with HSA2, HSA15, and HSA16; SSC6 with HSA3, HSA6, and HSA20; SSC7 with HSA11; SSC8 with HSA3,
HSA6, and HSA7; SSC9 with HSA8; SSC13 with HSA1; SSC14 with HSA13; SSC15 with HSA19; SSC16 with HSA9.
Received: 19 December 2000 / Accepted: 13 March 2001 相似文献
996.
Lead poisoning was produced in suckling rats by lead fed to lactating mother rats being transmitted to newborns maternal milk. The brain of 25 day old lead poisoned rats contained 6.0 to 12.5 ppm lead. Zinc was depressed 56% (cerebral cortex), 45% in cerebellum and 43% (caudate nucleus) whereas copper was depressed 52% in the cerebellum. Inhibition of monoamine oxidase (pargyline) or partial depletion of serotonin and norepinephrine did not alter the concentration of Fe, Cu, Zn, or Mn in brain. 相似文献
997.
998.
999.
Michael A. Harkey Arthur H. Whiteley 《In vitro cellular & developmental biology. Plant》1985,21(2):108-113
Summary A procedure is described for large-scale isolation of micromeres from 16-cell stage sea urchin embryos. One to two grams of
>99% pure, viable micromeres (2.3 to 4.6 × 108 cells) are routinely isolated in a single preparation. In culture, these cells uniformly proceed through their normal development,
in synchrony with micromeres in whole embryos, ultimately differentiating typical larval skeletal structures. The attributes
of this procedure are: (a) the very early time of isolation of the cells, directly after the division that establishes the
cell line; (b) the large yield of cells; (c) the purity of the preparation of cell; and (d) their synchronous development
in culture through skeletogenesis. The procedure greatly aids in making sea urchin micromeres a favorable material for molecular
analysis of development.
This work was supported in part by the following grants from the National Institutes of Health: Grant HL-10312 to A.H.W.,
Grant GM-20784 to Helen R. Whiteley, Grant ES-02190 to N. Karle Mottet, M.D., and Training Grants ES-07032 and HD-00266. 相似文献
1000.