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661.
In field trials in 1976 and 1977 various granular formulations of aldicarb (2–8 to 12.8 kg a.i. ha-1 ) were applied to sugar-beet fields infested with Heterodera schachtii . The levels of toxic residues of aldicarb and of H. schachtii populations in the soil were monitored at intervals throughout the sugar-beet season.
A severe drought in 1976 seriously affected the field trials and although aldicarb levels were maintained in the soil no aldicarb treatment proved effective in controlling H. schachtii; this was probably due to lack of mobility of the pesticide in the soil. In 1977, the final nematode populations in plots treated with 2.8 or 11.2 kg a.i. ha-1 added incrementally through the growing season to simulate the effect of a controlled release formulation were not significantly different from those of untreated plots. In contrast treatment at drilling with fast-releasing formulations at all application rates did promote control of H. schachtii populations. No significant increase in yield was found on any trial after treatment with aldicarb.
The value of controlled release formulations of aldicarb for the control of H. schachtii populations over the growing season has not been proven. 相似文献
A severe drought in 1976 seriously affected the field trials and although aldicarb levels were maintained in the soil no aldicarb treatment proved effective in controlling H. schachtii; this was probably due to lack of mobility of the pesticide in the soil. In 1977, the final nematode populations in plots treated with 2.8 or 11.2 kg a.i. ha
The value of controlled release formulations of aldicarb for the control of H. schachtii populations over the growing season has not been proven. 相似文献
662.
663.
In 1967 and 1968 respectively 10450 and 8665Salmonella strains were screened for resistance to ampicillin, chloramphenicol and tetracycline. It was found that in 1967, 17.8% and in 1968, 14.6% of the isolated strains were resistant to one or more antibiotics. Most strains appeared to be only tetracycline-resistant. Strains from human sources that were only ampicillin-resistant increased from 0.8 % in 1965 to 3.2% in 1967, and then decreased in 1968 to 1.3%. Resistance to chloramphenicol remained low (1.4% and lower). 相似文献
664.
Reinout Heijungs Jeroen Guinée René Kleijn Vera Rovers 《The International Journal of Life Cycle Assessment》2007,12(4):211-216
Introduction Normalization is an optional step in LCIA that is used to better understand the relative importance and magnitude of the impact
category indicator results. It is used for error checking, as a first step in weighting, and for standalone presentation of
results. A normalized score for a certain impact category is obtained by determining the ratio of the category indicator result
of the product and that of a reference system, such as the world in a certain year or the population of a specific area in
a certain year.
Biased Normalization In determining these two quantities, the numerator, the denominator, or both can suffer from incompleteness due to a lack
of emission data and/or characterisation factors. This leads to what we call a biased normalization. As a consequence. the
normalized category indicator result can be too low or too high. Some examples from hypothetical and real case studies demonstrate
this.
Consequences of Biased Normalization Especially when for some impact categories the normalized category indicator result is right, for others too low, and for
others too high, severe problems in using normalized scores can show up. It is shown how this may affect the three types of
usage of normalized results: error checking, weighting and standalone presentation.
Detection and Remedies of Biased Normalization Some easy checks are proposed that at least alert the LCA practitioner of the possibility of a biased result. These checks
are illustrated for an example system on hydrogen production. A number of remedies of this problem is possible. These are
discussed. In particular, casedependent normalization is shown to solve some problems, but on the expense of creating other
problems.
Discussion It appears that there is only one good solution: databases and tables of characterisation factors must be made more completely,
so that the risk of detrimental bias is reduced. On the other hand, the use of the previously introduced checks should become
a standard element in LCA practice, and should be facilitated with LCA software.
ESS-Submission Editor: Duane A. Tolle (tolled@battelle.org) 相似文献
665.
A phage-typing scheme forSalmonella panama has been established. This was done according to the method of Craigie and Yen by means of phage preparations which are all derived from a single phage. So far, eight phage types and a restgroup Z could be demonstrated by means of phage 47 and seven adaptations derived from it. 相似文献
666.
GAËL LE PENNEC MARCEL LE PENNEC PETER BENINGER SUZANNE DUFOUR 《Invertebrate reproduction & development.》2013,57(1-3):13-19
Summary Bathypecten vulcani is considered a relict species from the Paleozoic, based on shell characteristics such as the presence of calcite prisms. To date, it is the only pectinid species reported from hydrothermal ecosystems. Histological and ultrastructural studies show that spermatogenesis is identical to that of littoral pectinids. The spermatozoon has a 2.7 μm long pyriform head and a 40 μm flagellum. The four mitochondria of the mid-piece are about 1.2 μm in diameter. The nucleus contains dense chromatin fibres and possesses a wide, shallow (0.1 μm) anterior fossa and a narrow, deeper (0.2 μm) posterior nuclear fossa. Comparison of the ultrastructural characteristics of the spermatozoon of B. vulcani with those of littoral pectinids shows that they can be used as a diagnostic feature of this species. In particular, its acrosome characters will be a useful complement to the shell characters in the study of the phylogenetic position of this species in relation to other pectinids. 相似文献
667.
668.
In this study, we have analyzed the melanogenic potential of Schwann cells using in vitro cell cultures of embryonic quail peripheral nerves. It is shown that in Schwann cells, two factors, 12‐O‐tetradecanoylphorbol‐13 acetate (TPA) and endothelin 3, trigger a differentiation pathway toward melanocytes, and that Steel factor has no effect on these cells unless treated simultaneously with TPA. In these cultures, TPA induces the expression of c‐kit, whereas Steel factor enhances the development of melanocytes. In the assay system we employed, neither neuronal nor catecholaminergic phenotypes were obtained, regardless of various combinations of related factors added to the culture medium. These data support our previous observations indicating the existence of bipotent progenitors that are capable of differentiating into Schwann cells or into melanocytes, and the regulatory role of endothelin 3 on those precursors, as revealed by the clonal culture of neural crest cells. 相似文献
669.
670.
An assessment of a method based on intrinsic antibiotic resistance for identifying Rhizobium strains
A method based on intrinsic antibiotic resistance (IAR) for identifying large numbers of Rhizobium strains was assessed and found to be unsatisfactory for R. phaseoli and isolates from Cicer arietinum (Rhizobium spp.). Our data showed that the number of different IAR patterns always exceeded the number of strains tested. With 90 nodule isolates from plants inoculated with a mixture of three strains of R. Phaseoli, the technique gave 18 different resistance patterns. When 24 strains of Rhizobium spp., each replicated three times, were examined 68 different resistance patterns were obtained. Single colony isolates from one strain also gave several different IAR patterns. All strains tested with fluorescent“ antibody were readily identified. Attempts to obtain correct strain identification with IAR by simplifying the scoring systems or allowing up to two differences in the resistance patterns were unsuccessful. We were unable to define the source of this variation although incubation time and inoculum concentration were shown to affect the IAR patterns 相似文献