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排序方式: 共有311条查询结果,搜索用时 15 毫秒
251.
Tetsushi HIRANO Shogo YANAI Takuya OMOTEHARA Rie HASHIMOTO Yuria UMEMURA Naoto KUBOTA Kiichi MINAMI Daichi NAGAHARA Eiko MATSUO Yoshiko AIHARA Ryota SHINOHARA Tomoyuki FURUYASHIKI Youhei MANTANI Toshifumi YOKOYAMA Hiroshi KITAGAWA Nobuhiko HOSHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(10):1207-1215
Neonicotinoids, some of the most widely used pesticides in the world, act as agonists to
the nicotinic acetylcholine receptors (nAChRs) of insects, resulting in death from
abnormal excitability. Neonicotinoids unexpectedly became a major topic as a compelling
cause of honeybee colony collapse disorder, which is damaging crop production that
requires pollination worldwide. Mammal nAChRs appear to have a certain affinity for
neonicotinoids with lower levels than those of insects; there is thus rising concern about
unpredictable adverse effects of neonicotinoids on vertebrates. We hypothesized that the
effects of neonicotinoids would be enhanced under a chronic stressed condition, which is
known to alter the expression of targets of neonicotinoids, i.e.,
neuronal nAChRs. We performed immunohistochemical and behavioral analyses in male mice
actively administered a neonicotinoid, clothianidin (CTD; 0, 10, 50 and 250 mg/kg/day),
for 4 weeks under an unpredictable chronic stress procedure. Vacuolated seminiferous
epithelia and a decrease in the immunoreactivity of the antioxidant enzyme glutathione
peroxidase 4 were observed in the testes of the CTD+stress mice. In an open field test,
although the locomotor activities were not affected, the anxiety-like behaviors of the
mice were elevated by both CTD and stress. The present study demonstrates that the
behavioral and reproductive effects of CTD become more serious in combination with
environmental stress, which may reflect our actual situation of multiple exposure. 相似文献
252.
Yuria UMEMURA Ryosuke MIYAMOTO Rie HASHIMOTO Kyoko KINOSHITA Takuya OMOTEHARA Daichi NAGAHARA Tetsushi HIRANO Naoto KUBOTA Kiichi MINAMI Shogo YANAI Natsumi MASUDA Hideto YUASA Youhei MANTANI Eiko MATSUO Toshifumi YOKOYAMA Hiroshi KITAGAWA Nobuhiko HOSHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(12):1587-1598
Mammalian sexual fate is determined by the presence or absence of sex determining
region of the Y chromosome (Sry) in the “bipotential” gonads.
Recent studies have demonstrated that both male and female sexual development are induced
by distinct and active genetic pathways. Breeding the Y chromosome from Mus m.
domesticus poschiavinus (POS) strains into C57BL/6J (B6J) mice
(B6J-XYPOS) has been shown to induce sex reversal (75%: bilateral ovary, 25%:
true hermaphrodites). However, our B6N-XYPOS mice, which were generated by
backcrossing of B6J-XYPOS on an inbred B6N-XX, develop as males (36%: bilateral
testis with fertility as well as bilateral ovary (34%), and the remainder develop as true
hermaphrodites. Here, we investigated in detail the expressions of essential sex-related
genes and histological features in B6N-XYPOS mice from the fetal period to
adulthood. The onsets of both Sry and SRY-box 9 (Sox9) expressions as determined
spatiotemporally by whole-mount immunohistochemistry in the B6N-XYPOS gonads
occurred 2–3 tail somites later than those in B6N-XYB6 gonads, but earlier than
those in B6J-XYPOS, respectively. It is possible that such a small difference
in timing of the Sry expression underlies testicular development in our
B6N-XYPOS. Our study is the first to histologically show the expression and
ectopic localization of a female-related gene in the XYPOS testes and a
male-related gene in the XYPOS ovaries. The results from these and previous
experiments indicate that the interplay between genome variants, epigenetics and
developmental gene regulation is crucial for testis development. 相似文献
253.
Masaya IGASE Kenji BABA Takako SHIMOKAWA MIYAMA Shunsuke NOGUCHI Takuya MIZUNO Masaru OKUDA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(11):1507-1510
A 6-year-old spayed female Jack Russell Terrier presented with a 1-month
history of lethargy, anorexia, vomiting and weight loss. The dog was fed beef and chicken
jerky treats daily in addition to a commercial diet. Laboratory tests revealed azotemia,
hypokalemia, hyperchloremia, metabolic acidosis and glucosuria with normoglycemia. Urine
amino acid analysis showed significant amino acid loss into the urine. Thus, Fanconi
syndrome was diagnosed, and based on the case history and extensive diagnostic testing,
excessive consumption of jerky treats was strongly suspected as the cause. Glucosuria
resolved 7 days after the withdrawal of jerky treats and fluid therapy. Aminoaciduria was
substantially, but not completely, improved 3 months after diagnosis. Mild azotemia
remained, suggesting chronic renal disease. To the best of our knowledge, this is the
first reported case of Fanconi syndrome following the consumption of jerky treats in
Japan. 相似文献
254.
Hiroaki Maeda Takuya Yamaguchi Motoyasu Omoteno Takeshi Takarada Kenji Fujita Kazumasa Murata Yukihide Iyama Yoichiro Kojima Makiko Morikawa Hidenobu Ozaki Naoyuki Mukaino Yoshinori Kidani Takeshi Ebitani 《Breeding Science》2014,64(2):134-141
Rice (Oryza sativa L.) can produce black grains as well as white. In black rice, the pericarp of the grain accumulates anthocyanin, which has antioxidant activity and is beneficial to human health. We developed a black rice introgression line in the genetic background of Oryza sativa L. ‘Koshihikari’, which is a leading variety in Japan. We used Oryza sativa L. ‘Hong Xie Nuo’ as the donor parent and backcrossed with ‘Koshihikari’ four times, resulting in a near isogenic line (NIL) for black grains. A whole genome survey of the introgression line using DNA markers suggested that three regions, on chromosomes 1, 3 and 4 are associated with black pigmentation. The locus on chromosome 3 has not been identified previously. A mapping analysis with 546 F2 plants derived from a cross between the black rice NIL and ‘Koshihikari’ was evaluated. The results indicated that all three loci are essential for black pigmentation. We named these loci Kala1, Kala3 and Kala4. The black rice NIL was evaluated for eating quality and general agronomic traits. The eating quality was greatly superior to that of ‘Okunomurasaki’, an existing black rice variety. The isogenicity of the black rice NIL to ‘Koshihikari’ was very high. 相似文献
255.
The diameter growth of trees may vary depending on the tree size, species and other tree-related factors. However, such variation is challenging to consider while estimating the growth response to weather conditions. This study investigated the effects of the weather conditions and variations in tree factors on diameter growth in a mature forest. In particular, we focused on diameter growth in June, the month of active diameter growth. We recorded the monthly diameter growth of 6 tree species for 7 years and constructed a generalized linear mixed model in which the mean growth was dependant on tree size, weather conditions, and the interaction between tree size and weather. 相似文献
256.
Masatake G. Araki Hajime Utsugi Takuya Kajimoto Qingmin Han Tatsuro Kawasaki Yukihiro Chiba 《Journal of Forest Research》2010,15(2):115-122
We examined vertical and seasonal variations in stem respiration rates in a 50-year-old plantation of Japanese cypress, Chamaecyparis obtusa (Sieb. et Zucc.) Endl., in central Japan, and discuss a practical and precise method to scale a point-measured stem CO2 efflux rate up to whole-stem respiration. For five selected trees, stem CO2 efflux rates were measured at breast height (1.3 m) and at five or six points above breast height (at approximately 2 m intervals)
every 1 or 2 months over two consecutive years. Daily total stem respiration rate (surface area basis) was greater inside
the crown than below the crown, especially during the growing season. By incorporating the vertical profile of the respiration
rate, annual whole-stem respiration was estimated for each sample tree (R
y). We then compared this estimate (R
y) with another estimate of annual whole-stem respiration (R′y) obtained using a conventional method; it is assumed that the area-based respiration rate at breast height is constant throughout
the stem. The ratio of these two estimates (R′y/R
y) was usually less than 1, indicating that the assumptions used to calculate R′y underestimate annual whole-stem respiration. We found that R′y/R
y was negatively correlated with the ratio of crown length to tree height (crown ratio). These results suggest that annual
whole-stem respiration in this C. obtusa plantation is substantially affected by the relative proportion of within-crown stem with higher respiratory activity. Methodologically,
our results imply that incorporating the crown ratio into the conventional method would improve the accuracy of annual whole-stem
respiration estimates. 相似文献
257.
258.
Yasuyuki Matsushita Takuya Sekiguchi Ryoichi Ichino Kazuhiko Fukushima 《Journal of Wood Science》2009,55(5):344-349
Electropolymerization of coniferyl alcohol was carried out in an aqueous system (0.2 M NaOH) and in an organic solvent system
[CH2Cl2/methanol (4:1 v/v) in the presence of 0.2 M LiClO4] to produce a dehydrogenation polymer (DHP) - artificial lignin. In both systems, the polymerization of coniferyl alcohol
was visually confi rmed. In the aqueous system, no dimer was detected in the reaction medium after electropolymerization,
suggesting that endwise polymerization occurred on the electrode surface. Thioacidolysis degradation revealed that the obtained
polymers had numerous 8-O-4′ linkages. The electropolymerization products obtained in the organic solvent system also had numerous 8-O-4′ linkages; in particular, the polymers obtained in the initial polymerization stage. This was probably because of the limited
area available for reaction and the orientation of coniferyl alcohol on the electrode surface controlled the polymerization. 相似文献
259.
Tomonori KAMEDA Hideyuki NAKASHIMA Takumi TAKIZAWA Fumihito MIURA Takashi ITO Kinichi NAKASHIMA Takuya IMAMURA 《The Journal of reproduction and development》2021,67(6):369
Post-mitotic neurons do exhibit DNA methylation changes, contrary to the longstanding belief that the epigenetic pattern in terminally differentiated cells is essentially unchanged. While the mechanism and physiological significance of DNA demethylation in neurons have been extensively elucidated, the occurrence of de novo DNA methylation and its impacts have been much less investigated. In the present study, we showed that neuronal activation induces de novo DNA methylation at enhancer regions, which can repress target genes in primary cultured hippocampal neurons. The functional significance of this de novo DNA methylation was underpinned by the demonstration that inhibition of DNA methyltransferase (DNMT) activity decreased neuronal activity-induced excitatory synaptogenesis. Overexpression of WW and C2 domain-containing 1 (Wwc1), a representative target gene of de novo DNA methylation, could phenocopy this DNMT inhibition-induced decrease in synaptogenesis. We found that both DNMT1 and DNMT3a were required for neuronal activity-induced de novo DNA methylation of the Wwc1 enhancer. Taken together, we concluded that neuronal activity-induced de novo DNA methylation that affects gene expression has an impact on neuronal physiology that is comparable to that of DNA demethylation. Since the different requirements of DNMTs for germ cell and embryonic development are known, our findings also have considerable implications for future studies on epigenomics in the field of reproductive biology. 相似文献
260.
Fisheries Science - Larvae of Auxis rochei and Auxis thazard are commonly found in tropical to temperate waters around the world; however, their identification is difficult due to their similar... 相似文献