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211.
David A. Caron Christopher J. Gobler Darcy J. Lonsdale Robert M. Cerrato Rebecca A. Schaffner Julie M. Rose Nathaniel J. Buck Gordon Taylor Katie Rose Boissonneault Reyhan Mehran 《Harmful algae》2004,3(4):439
Experiments were conducted with natural plankton assemblages from two areas in Great South Bay (GSB) and the Peconic Bays Estuary System, NY, to compare the rates of growth and pelagic grazing mortality of Aureococcus anophagefferens with co-occurring phytoplankton. We hypothesized that A. anophagefferens would experience low mortality rates by microbial herbivores (relative to feeding pressure on other algae) thus providing it with a competitive advantage within the phytoplankton community. In fact, substantial rates of mortality were observed in nearly every experiment in our study. However, mortality rates of A. anophagefferens were less than intrinsic growth rates of the alga during late spring and early summer in Great South Bay, resulting in positive net growth rates for the alga during that period. This timing coincided with the development of a brown tide in this estuary. Similarly, growth rates of the alga also exceeded mortality rates during bloom development in natural plankton assemblages from the Peconic Bays Estuary System held in mesocosms. In contrast to the situation for A. anophagefferens, growth rates of the total phytoplankton assemblage, and another common picoplanktonic phytoplankter (Synechococcus spp.), were frequently less than their respective mortality rates. Mortality rates of A. anophagefferens in both systems were similar to growth rates of the alga during later stages of the bloom. Laboratory studies confirmed that species of phagotrophic protists that consume A. anophagefferens (at least in culture) are present during brown tides but preference for or against the alga appears to be species-specific among phagotrophic protists. We conclude that two scenarios may explain our results: (1) protistan species capable of consuming the brown tide alga were present at low abundances during bloom initiation and thus not able to respond rapidly to increases in the intrinsic growth rate of the alga, or (2) the brown tide alga produced substance(s) that inhibited or retarded protistan grazing activities during the period of bloom initiation. The latter scenario seems less likely given that significant mortality of A. anophagefferens was measured during our field study and mesocosm experiment. However, even a minor reduction in mortality rate due to feeding selectivity among herbivores might result in a mismatch between growth and grazing of A. anophagefferens that could give rise to significant net population growth of this HAB species. Either scenario infers an important role for trophic interactions within the plankton as a factor explaining the development of brown tides in natural ecosystems. 相似文献
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Houle Alain Chapman Colin A. Vickery William L. 《International journal of primatology》2004,25(1):237-260
Primate ecological studies can benefit from accessing the canopy to estimate intra-tree and inter-tree variation in food availability and nutrient value, patch and subpatch depletion, foraging efficiency, as well as nest structure and nesting behaviors, parasitic transmission and predator detectability. We compare several ways to access the canopy and examine their suitability for studies of primates. Two of them—the Single Rope Technique and the Climbing Spur Method—allow people to safely access almost all kinds of trees, regardless of their size, height or shape. Modern climbing gear and contemporaneous safety protocols, derived from rock climbers, speleologists, and industrial arborists, are reliable and appropriate for primate ecological studies. Climbing gear is specialized and still expensive for students, but tree climbing can be dangerous during specific maneuvres. Consequently, formal training and preliminary experience are essential before attempting to collect data. We discuss the physics of falling, risk assessment associated with a fall, knots, gear and safety precautions. Finally, we propose a Tree Climbing Safety Protocol adapted for 2 climbing methods and primate field ecology. Researchers should be aware that climbing safety depends on their own judgment, which must be based on competent instruction, experience, and a realistic assessment of climbing ability. Therefore, the information we provide should be used only to supplement competent personal instruction and training in situ. Although most primate observations have been and will mostly be done from the ground in the future, canopy information complements the observations. Canopy data will add a significant new dimension to our knowledge of primates by providing strategic information otherwise unavailable. 相似文献
215.
2-维凝胶电泳(2DE)具有高分辨率、高通量等特点,已被广泛地用于蛋白质组的研究.然而,2DE-MS在膜蛋白质组学研究方面却有其局限性,主要因为:膜蛋白具有低丰度、难溶、等电点时易沉淀、难酶解等特点.然而随着亚细胞分离技术和直接的生化方法富集等技术的发展,低丰度问题得到了极大的改善;增溶剂(尿素,硫脲),新的两性离子和非离子去垢剂,以及有机溶剂等的利用极大地改善了膜蛋白质组的溶解性能;同时,一些新的2DE技术的利用扩大了常规2DE的分离范围.在膜蛋白裂解方面,将酶解法与化学法(CNBr)相结合,另外先进的质谱技术的发展使得膜蛋白质组的研究在最近几年取得了较大的发展.现对2DE-MS途径中,膜的富集、膜蛋白的提取、分离、酶解、鉴定方面的进展进行综述. 相似文献
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Effects of post-teneral diet on foraging success of sterile male Mediterranean fruit flies 总被引:1,自引:1,他引:0
M. Maor B. Kamensky S. Shloush & B. Yuval 《Entomologia Experimentalis et Applicata》2004,110(3):225-230
Post‐teneral diets containing protein have been shown to enhance the copulatory success of sterile male Mediterranean fruit flies, Ceratitis capitata (Wied.) (Diptera: Tephritidae). However, ingesting protein was also found to negatively affect male survival, in particular when males faced starvation following release in the field. Accordingly, the objective of the present study was to determine the effects of various post‐teneral diets, presented to sterile males prior to release, on their subsequent ability to forage for carbohydrates and protein in the field. Using mark‐release recapture and analytic biochemical methods, we found that both protein‐fed and protein‐deprived males foraged successfully for protein and sugar in a field enclosure when these resources were available. We conclude that protein‐fed sterile males are able to exploit sources of nutrition in the release environment, and their inability to overcome starvation is not a concern for control operations using the sterile insect technique. 相似文献
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H. J. Barclay 《Population Ecology》2001,43(3):197-206
Models were constructed for control of a pest species by the release of sterile insects and these models explored the consequences
of incomplete sterility. This feature was then coupled with the lack of competitive ability of released insects, the immigration
of insects from outside the control area, and the mode of population regulation (density independent vs. density dependent).
Using the density-independent models, it was seen that the limits on residual fertility of treated insects become much more
stringent when incomplete sterilization is combined with a lack of competitive ability and immigration of insects into the
control area. Strong density dependence in the system has a marked moderating effect on the requirements for sterility, competitive
ability, and immigration. However, if the density-independent limits on these factors are exceeded, then suppression is possible,
but collapse of the pest population is impossible using sterile releases alone. Even suppression might not be satisfactory
if these three detrimental factors are prominent. It is suggested that one remedy is the use of the sterile release method
in combination with other control methods.
Received: January 18, 2001 / Accepted: August 7, 2001 相似文献
220.
端粒酶反义cDNA对乳腺癌细胞损伤修复能力的影响 总被引:3,自引:0,他引:3
利用反义核酸技术将端粒酶RNA的全长cDNA反向导入乳腺癌MCF 7细胞基因组中 .通过单细胞凝胶电泳实验发现 ,其DNA受H2 O2 损伤后的修复能力下降 .但端粒酶活性抑制为何引起其DNA损伤修复能力下降的原因尚待进一步研究 . 相似文献