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101.
The recent discovery of a hyper-metal-poor (HMP) star, with a metallicity Fe/H smaller than 1/100,000 of the solar ratio, together with one earlier HMP star, has raised a challenging question whether these HMP stars are the actual first-generation, low-mass stars of the universe. We argue that these HMP stars are second-generation stars formed from gases that were chemically enriched by the first-generation supernovae. The key to this solution is the very unusual abundance patterns of these HMP stars and the similarities and differences between them. We can reproduce these abundance features with core-collapse "faint" supernova models that include extensive matter mixing and fallback during explosions. 相似文献
102.
Fuji Shin-ichi Mochizuki Tomofumi Okuda Mitsuru Tsuda Shinya Kagiwada Satoshi Sekine Ken-Taro Ugaki Masashi Natsuaki Keiko T. Isogai Masamichi Maoka Tetsuo Takeshita Minoru Yoshikawa Nobuyuki Mise Kazuyuki Sasaya Takahide Kondo Hideki Kubota Kenji Yamaji Yasuyuki Iwanami Toru Ohshima Kazusato Kobayashi Kappei Hataya Tatsuji Sano Teruo Suzuki Nobuhiro 《Journal of General Plant Pathology》2022,88(2):105-127
Journal of General Plant Pathology - An increasing number of plant viruses and viroids have been reported from all over the world due largely to metavirogenomics approaches with technological... 相似文献
103.
Background
Virus-induced gene silencing (VIGS) is an effective technology for the analysis of gene functions in plants. Though there are many reports on virus vectors for VIGS in plants, no VIGS vectors available for Rosaceae fruit trees were reported so far. We present an effective VIGS system in apple, pear, and Japanese pear using Apple latent spherical virus (ALSV) vectors.Results
Inoculation of ALSV vectors carrying a partial sequence of endogenous genes from apple [ribulose-1, 5-bisphosphate carboxylase small subunit (rbcS), alpha subunit of chloroplast chaperonin (CPN60a), elongation factor 1 alpha (EF-1a), or actin] to the cotyledons of seeds by a particle bombardment induced highly uniform knock-down phenotypes of each gene on the true leaves of seedlings from 2~3 weeks after inoculation. These silencing phenotypes continued for several months. Northern blot and RT-PCR analyses of leaves infected with ALSV containing a fragment of rbcS gene showed that the levels of rbcS-mRNA drastically decreased in the infected apple and pear leaves, and, in reverse, rbcS-siRNAs were generated in the infected leaves. In addition, some of apple seedlings inoculated with ALSV vector carrying a partial sequence of a TERMINAL FLOWER 1 gene of apple (MdTFL1) showed precocious flowering which is expected as a knock-down phenotype of the silencing of MdTFL1 gene.Conclusions
The ALSV-based VIGS system developed have provides a valuable new addition to the tool box for functional genomics in apple, pear, and Japanese pear. 相似文献104.
Tetsushi Nagano Nobuyuki Yanase Yukiko Hanzawa Morio Takada Hisayoshi Mitamura Tsutomu Sato Hirochika Naganawa 《Water, air, and soil pollution》2011,216(1-4):153-166
In order to evaluate fixation potential of schwertmannite for fluvial transport of various toxic elements, we examined bottom precipitates and stream waters collected from the rivers contaminated with acid mine drainage (AMD), which arose from the abandoned Nishinomaki mine (Shimonita, Gunma, Japan). Mineralogical and morphological observations revealed that schwertmannite was the main mineral of the precipitates. The affinity of various toxic ions to schwertmannite was evaluated on the basis of (1) apparent solid?Cliquid partition coefficients (K d??s) between precipitates and stream waters, (2) coprecipitation behaviors during schwertmannite formation in a laboratory test, and (3) consideration on coprecipitation processes using partial charge model (PCM). As a result, oxyanions of V, As, Mo and Sb, K d??s of which were relatively large (>104 (ml g?1)), were considered to be immobilized by schwertmannite precipitates. A laboratory test also demonstrated that these ions except Mo coprecipitated with schwertmannite. In addition, partial charges and average electronegativities predicted on the basis of PCM suggested that the oxyanions of V, As, Mo, and Sb could create stable inner sphere complexes with schwertmannite embryos, which results in their high affinity to schwertmannite. On the other hand, cationic ions of Mn, Cu, Zn, Sr, Cs, and U, K d??s of which were relatively small (<104 (ml g?1)), were thought to have a tendency to flow downstream without uptake by schwertmannite precipitates. All these results suggested that schwertmannite has high fixation potential for fluvial transport of various toxic oxyanions in AMD-contaminated rivers. 相似文献
105.
Haraguchi K Kato Y Ohta C Koga N Endo T 《Journal of agricultural and food chemistry》2011,59(24):13102-13109
Marine sponges collected in Palau, Micronesia, were investigated for hydroxylated or methoxylated analogues of brominated diphenyl ethers (BDEs), brominated dibenzo-p-dioxin (BDD), and brominated biphenyls. The neutral fractions of Haliclona sp. and Callyspongia sp. contained 2'-methoxy-2,3',4,5'-tetraBDE, 6-methoxy-2,2',4,4'-tetraBDE, 2',6-dimethoxy-2,3',4,5-tetraBDE 2,2'-dimethoxy-3,3',5,5'-tetrabromobiphenyl, several methoxy-triBDEs, and dimethoxy-penta-/hexaBDEs. The methoxylated BDEs in sponges were strikingly similar to those of local fish living in the western Pacific Ocean. The total concentrations of these compounds (ΣMeO-PBDE) in both sponges were 63.5 μg/g extractable organic matter (EOM) for Haliclona sp. and 36.5 μg/g EOM for Callyspongia sp., which were about 2 orders of magnitude higher than the levels seen in tropical coral reef fish (unicornfish or surgeonfish) (280-290 ng/g lipid) and groupers (550 ng/g lipid) from Okinawan coastal waters. The phenolic fractions of both sponges contained hydroxy-methoxy tetra-/pentaBDEs as well as hydroxy-tetraBDD, in addition to the corresponding phenolic tetraBDE analogues. Although the total concentrations of phenolic products (27-80 μg/g EOM) in both sponges fell within a range comparable to the methoxylated products, ΣOH-PBDE in local fish were trace level (less than 10 ng/g lipid of) or undetectable. This survey indicates that marine sponges are a possible source of the MeO-PBDE analogues that biomagnify via the food chain to the higher trophic organisms in the western Pacific, whereas the distribution of the corresponding hydroxylated analogues is limited. 相似文献
106.
Kazuhiro Maejima Eiji Uheda Nobuyuki Shiomi Shunji Kitoh 《Soil Science and Plant Nutrition》2013,59(3):447-449
The relationship between nitrogen fixation and the numbers of cyanobionts and heterocysts in the mature leaves of fifteen Azolla strains from five species was examined. The nitrogenase (acetylene reduction) activity per leaf and the numbers of cyanobionts and heterocysts in the mature region varied depending on the Azolla strains. The numbers of cyanobionts and heterocysts, particularly the number of heterocysts, were closely correlated with the nitrogenase activity per leaf. However, the nitrogenase activity per leaf was not correlated with the nitrogenase activity per heterocyst. The results indicate that the variation in the nitrogenase activity of the leaves among Azolla strains mainly resulted from the variation in the number of heterocysts and not from the variation in the nitrogenase activity per heterocyst. 相似文献
107.
108.
Youichi Ikeshita Yuri Kanamori Nobuyuki Fukuoka Jun Matsumoto Yasutaka Kano 《Scientia Horticulturae》2010
To investigate the effects of night-time temperature on cell and fruit size, and sugar accumulation in watermelon fruit, fruits were treated with high night-time temperatures in a greenhouse. The minimum night-time ambient temperature of the heating box (18 °C) was approximately 6 °C higher than that of the control. The length, diameter and weight of heat-treated fruit at the end of heating treatment, 16 days after anthesis (DAA), were significantly greater than that of control fruit, but those at harvesting, 42 DAA, were almost the same in both treatments. Mean cell size of the outer portion of heat-treated fruit at 16 DAA was significantly larger than that of the control. Cell size of the fruits at 42 DAA did not differ between heat-treated and control fruits. Sucrose, glucose and fructose content of fruit at 16 DAA did not differ between heat-treated and control fruit. However, sucrose content of the outer portion of heat-treated fruit was 162% of that of control fruit at 42 DAA. Glucose and fructose contents at 42 DAA did not differ between heat-treated and control fruit, except glucose content of outer portion. 相似文献
109.
Wakabayashi N Tsujino M Tajiri M Taki M Koshino A Ikeda H Fukushima N Tsujiuchi T 《Journal of toxicologic pathology》2010,23(1):63-66
Lysophosphatidic acid (LPA) is a bioactive phospholipid that stimulates cell proliferation and migration, and protects cells from apoptosis. It interacts with specific G protein-coupled transmembrane receptors. Recently, frequent mutations of the LPA receptor-1 (LPA1) gene were detected in rat lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP). In this study, to evaluate the involvement of other LPA receptor gene alterations during lung carcinogenesis, we investigated mutations of the LPA2, LPA3, LPA4 and LPA5 genes in lung adenocarcinomas induced by BHP in rats. Fifteen male Wistar rats, 6 weeks of age, were given 2000 ppm BHP in their drinking water for 12 weeks and then maintained without further treatment until sacrifice at 25 weeks, and 15 adenocarcinomas were obtained. Genomic DNAs were extracted from frozen tissues, and the LPA2, LPA3, LPA4 and LPA5 genes were examined for mutations, using polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. No mutations of LPA2, LPA3, LPA4 and LPA5 were detected in the 15 adenocarcinomas. These results suggest that alterations due to LPA2, LPA3, LPA4 and LPA5 gene mutations might not be involved in the development of lung adenocarcinomas induced by BHP in rats. 相似文献
110.
Hideaki Tanoue Teruhisa Komatsu Takurou Tsujino Ippei Suzuki Masayoshi Watanabe Hideki Goto Nobuyuki Miyazaki 《Fisheries Science》2012,78(3):533-538
The feeding events of wild animals have been widely researched in recent decades. The use of invasive methods to determine
stomach contents in which the fish is killed can, however, be considered to be unjustifiable in the case of an endangered
fish, such as the Japanese late. Here, we report on a method that can be used to verify feeding events of a fish species without
the need for killing the fish through the use of a high-speed video camera and a three-axis micro-acceleration data-logger.
High-quality images obtained by the video showed that the fish opens its mouth with a quick downward movement of the mandibles
and ingests prey via suction feeding. The movement of the mandibles was also simultaneously recorded by changes in the three-axis
accelerations obtained by the logger attached to the dorsum. We attached the logger with an automatic release system to the
dorsum of one captive Japanese lates and two wild fish together with an acoustic transmitter and then released the fish in
the Shimanto River in Japan. After retrieving the logger, the movement records of the fish obtained by the three-axis accelerometer
showed the same pattern of feeding events as those in captivity. A total of 13 feeding events at night and five during the
daytime were obtained for the three fish during a total 129.7 h of recording. 相似文献