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排序方式: 共有224条查询结果,搜索用时 15 毫秒
71.
Y Deng J Zhao D Sakurai KM Kaufman JC Edberg RP Kimberly DL Kamen GS Gilkeson CO Jacob RH Scofield CD Langefeld JA Kelly ME Alarcón-Riquelme BIOLUPUS GENLES Networks JB Harley TJ Vyse BI Freedman PM Gaffney KM Sivils JA James TB Niewold RM Cantor W Chen BH Hahn EE Brown PROFILE BP Tsao 《Arthritis research & therapy》2012,14(Z3):A5
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Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin
lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed
from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and
their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly
treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group
UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August
due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move
to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better
weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the
value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture
infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better
despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments
of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without
dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where
routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed. 相似文献
75.
MR Scrochi CN Zanuzzi N Fuentealba F Nishida ME Bravi ME Pacheco 《Biotechnic & histochemistry》2017,92(8):560-568
Many viruses alter different stages of apoptosis of infected cells as a strategy for successful infection. Few studies have addressed mechanisms of equine herpesvirus 1 (EHV-1) strain-induced cell death. We investigated the effect of an abortigenic strain (AR8 strain) on heterologous Madin–Darby bovine kidney cells and homologous equine dermis (ED) cells cell lines. We compared morphologic and biochemical features of early and late apoptosis at different postinfection times. We investigated translocation of phosphatidylserine to the cell surface, nuclear fragmentation and changes in the cytoskeleton using flow cytometry and annexin V/propidium iodide staining, DNA laddering, terminal deoxynucleotidyl transferase UTP nick-end labeling assay and immunofluorescence staining of cytokeratin 18 cleavage. AR8 EVH-1 strain interfered with apoptosis in both cell lines, particularly during the middle stage of the replication cycle; this was more evident in ED cells. Although this antiapoptotic effect has been reported for other alpha herpesviruses, our findings may help elucidate how EHV-1 improves its infectivity during its cycle. 相似文献
76.
在中国应用垂直波束雷达监测褐飞虱和其他水稻害虫迁飞的可行性 总被引:1,自引:0,他引:1
J.R.Riley A.D.Smith D.R.Reynolds 《Entomologia Sinica》2003,10(1):1-19
近年来,可用于昆虫迁飞研究且可自动运行的垂直波束雷达(vertical-looking radar,VLR)的发展使得对迁飞性害虫的周年长期自动监测成为可能。本文提供了我们对能否将这种雷达应用于中国的褐飞虱和其他水稻害虫的监测与预测体系以改善其综合治理的可行性研究结果。以往的研究已经表明,这些害虫一般在300—2000m高度迁飞;而我们根据褐飞虱的雷达和射有效截面的计算结果表明,目前使用的3.2cm波长的VLR对褐飞虱个体目标的最大可检测高度仅约240m;虽然建造一部8.8mm波长的VLR即可覆盖褐飞虱迁飞高度的绝大部分,但其造价和维护费用均过于昂贵。为此,一个更可行的解决方案是,以3.2cm波长的VLR作为包括大多数水稻害虫在内的个体较大的迁飞性害虫的监测工具。 相似文献
77.
The black rat, Rattus rattus, consists of five karyotypic forms—2n = 42 (high C-banding); 2n = 42 (low C-banding); 2n = 40; 2n = 38; 2n = 42 Mauritius. Here, we use isozyme electrophoresis and microcomplement fixation to elucidate the genetic distance and phylogenetic relationship among each of the various karyotypic forms of R. rattus and R. norvegicus . The results show that (1) the 2n = 42 Mauritius black rat (2n = 42Mau) is genetically very similar to the 2n = 38 form, suggesting that this island population has undergone very rapid chromosomal evolution; (2) the 2n = 40 form from the highlands of Sri Lanka is genetically distinct from the 2n = 38 form from the lowlands; the genetic difference is probably insufficient, however, to prevent future introgression; (3) the level of genetic differentiation occurring between the 2n = 42 forms on the one hand and the 2n = 38, 2n = 40 and 2n = 42 Mau forms on the other support the hybrid incompatability data in suggesting that the two groups are either full species or incipient species; (4) in contrast to data from amino acid composition of transferrin and from restriction endonuclease digests of mtDNA, the present data suggest that the various karyotypic forms of R. rattus are phylogenetically more closely related to each other than any is to R. norvegicus, and that they are related by a series 2n = 42 → 2n = 40 → 2n = 38; (5) the R. rattus/R. norvegicus divergence occurred 2–8 million years ago, whereas the various chromosomal forms of R. rattus diverged over the last 4 million years. 相似文献
78.
Molecular probes of phylogeny and biogeography in toads of the widespread genus Bufo 总被引:1,自引:0,他引:1
L R Maxson 《Molecular biology and evolution》1984,1(4):345-356
Genetic relationships among 25 species of Central and South American Bufo
and among representative North, Central, and South American, Asian, and
African Bufo were probed, using the quantitative immunological technique of
microcomplement fixation (MC'F) which indicated a clear separation of
North, Central, and South American lineages of Bufo. The South American
lineage likely diverged from the Central and North American lineages in the
Eocene; the latter two lineages diverged later, probably in the
mid-Oligocene. Some species groups of South American toads, defined on the
basis of traditional morphological studies, are genetically quite similar
within groups, whereas others are genetically divergent. The amount of
albumin evolution does not appear to parallel the amount of karyotypic,
morphological, ecological, or behavioral evolution documented. Comparisons
suggest that the African lineages separated from the American and Asian
lineages in the late Cretaceous, corresponding to the time of the final
separation of Gondwanaland, the southern supercontinent including the
modern continents of South America, Africa, Australia, Antarctica, and
India. The Asian lineages diverged from the lineage giving rise to all of
the American species in the early Paleocene.
相似文献
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Functional changes in human leukemic cell line HL-60. A model for myeloid differentiation 总被引:12,自引:0,他引:12 下载免费PDF全文
Polar solvents induce terminal differentiation in the human promyelocytic leukemia cell line HL-60. The present studies describe the functional changes that accompany the morphologic progression from promyelocytes to bands and poly-morphonuclear leukocytes (PMN) over 9 d of culture in 1.3 percent dimethylsulfoxide (DMSO). As the HL-60 cells mature, the rate of O(2-) production increase 18-fold, with a progressive shortening of the lag time required for activation. Hexosemonophosphate shunt activity rises concomitantly. Ingestin of paraffin oil droplets opsonized with complement or Ig increases 10-fold over 9 d in DMSO. Latex ingestion per cell by each morphologic type does not change significantly, but total latex ingestion by groups of cells increases with the rise in the proportion of mature cells with greater ingestion capacities. Degranulation, as measured by release of β-glucuronidase, lysozyme, and peroxidase, reaches maximum after 3-6 d in DMSO, then declines. HL-60 cells contain no detectable lactoferrin, suggesting that their secondary granules are absent or defective. However, they kill staphylococci by day 6 in DMSO. Morphologically immature cells (days 1-3 in DMSO) are capable of O(2-) generation, hexosemonophosphate shunt activity, ingestion, degranulation, and bacterial killing. Maximal performance of each function by cells incubated in DMSO for longer periods of time is 50-100 percent that of normal PMN. DMSO- induced differentiation of HL-60 cells is a promising model for myeloid development. 相似文献