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981.
Although emperors (Lethrinidae) are commercially important fisheries resources in tropical and subtropical waters, their home
range size and its spatial arrangement have not been sufficiently clarified. In the present study, the size and spatial arrangement
of the daytime home range of the thumbprint emperor Lethrinus harak were investigated by using a portable GPS receiver. In a 150 m × 200 m quadrat, 21 individuals of the species were identified
by their color pattern, and individuals were divided into four arbitrary size classes (class 1 < 20 cm TL ≤ class 2 < 25 cm
TL ≤ class 3 < 30 cm TL ≤ class 4). Fish tracking by snorkeling was conducted with the portable GPS receiver. Daytime site
fidelity of this species was high and there was a significant positive correlation between the home range size and fish total
length. Home ranges of same-sized individuals abutted each other (20.3% area overlap), whereas those of different-sized individuals
overlapped (48.3% area overlap). Agonistic behavior (attacking) occurred significantly more frequently between same-sized
individuals than between different-sized individuals. These results suggest that daytime home ranges of Lethrinus harak can be regarded as territories against same-sized individuals, but not different-sized individuals. 相似文献
982.
Changes in serum thyroxine (T4), estradiol-17β (E2) and testosterone (T) levels during the parr-smolt transformation (smoltification) were investigated in the masu salmon (Oncorhynchus masou) in 1985 and 1987. T4 showed a peak in levels at the early stage of smoltification and E2 and T levels peaked almost at the same time. There were no significant differences between the concentrations of serum hormones
in female and males. During smoltification, germ cells in the peri-nucleolus and spermatogonia stage were present in the ovary
and testis, respectively. These results suggest that E2 and T may be involved in smoltification in the masu salmon. 相似文献
983.
Yuuki Kawabata Kimio Asami Masato Kobayashi Taku Sato Koichi Okuzawa Hideaki Yamada Kenzo Yoseda Nobuaki Arai 《Fisheries Science》2011,77(1):79-85
A critical component of many releasing projects is the identification and subsequent implementation of optimal release strategies
that can decrease post-release predation mortalities. We performed laboratory experiments to investigate whether acclimation
to shelters affects the post-release survival of hatchery-reared black-spot tuskfish Choerodon schoenleinii in the presence of a reef-resident predator, the white-streaked grouper Epinephelus ongus. Tuskfish were exposed to groupers under three different experimental conditions/treatments: (1) acclimation of fish to shelters
prior to their exposure to groupers; (2) no acclimation of fish to shelters, but with shelters available during their exposure
to groupers; (3) fish not acclimated to shelters and no shelters available during their exposure to groupers. Tuskfish that
were acclimated to shelters utilized shelters more frequently than did non-acclimated fish, and the survival rate of acclimated
fish was higher than those of fish in the other treatments. These results suggest that pre-release acclimation to shelters
improves the post-release survival of hatchery-reared black-spot tuskfish. 相似文献
984.
Faruq Ahmed Masashi Yokota Seiichi Watanabe Yasuyuki Koike Susumu Segawa & Carlos Augusto Strüssmann 《Aquaculture Research》2005,36(8):799-802
The adoption of an upright posture in abalones is essential to enable them to use their foot, and hence to be able to move and seek shelter, as well as to avoid exposure of soft parts and possible predation. In mass restocking programs for abalone, juveniles are released by divers near the seabed, but without control over their posture when they reach the bottom. Thus, the time to recover the upright posture is an important consideration in abalone restocking programs as the quicker they assume this posture the higher the likelihood of survival. This study reports significant differences in the speed of recovering the upright posture between juveniles of the abalones Haliotis discus discus, H. gigantea and H. madaka and between tests conducted under stagnant and flowing water conditions. Longer times were required for recovery in all species in stagnant than flowing water. On average, juveniles of H. discus discus (17.16 and 10.43 s) and H. gigantea (22.54 and 11.89 s) recovered faster than those of H. madaka (161.13 and 49.02 s) under stagnant and flowing water conditions respectively. These results suggest that different species require different levels of care and that water flow or current at the time of release may affect post‐release survival. 相似文献
985.
Fumiaki Takakuwa Ryota Tanabe Shohei Nomura Takashi Inui Shinichi Yamada Amal Biswas Hideki Tanaka 《Aquaculture Research》2022,53(1):36-49
Black soldier fly meal (BM) is an outstanding candidate as a fish meal (FM) substitute because it contains relatively high protein and essential amino acids. In this study, we replaced FM in red sea bream diets (Pagrus major) with BM to investigate its effect on growth and feed utilization. Six isonitrogenous and isolipidic experimental diets were prepared by substituting 0%, 20%, 40%, 60%, 80% and 100% FM protein with BM (Control, BM20, BM40, BM60, BM80 and BM100, respectively). After the 8-week feeding trial, final body weight, weight gain, specific growth rate and feed efficiency decreased linearly with increasing dietary BM level (p < 0.05). Apparent digestibility of protein and fat and serum total cholesterol concentration decreased with increasing dietary BM levels (p < 0.05) Final body weight, WG, SGR and FE against dietary BM level had breaking points of 76.2%, 41.7%, 76.5% and 60.0%, respectively, in segmental regression analysis. In conclusion, the results suggest that BM can replace a maximum of 41.7% of FM in the diet of red sea bream without compromising growth performance or feed efficiency for 56 days. 相似文献
986.
Takafumi Fujimoto Aya Yamada Yukihiro Kodo Kohei Nakaya Michiko Okubo-Murata Taiju Saito Kazuto Ninomiya Michiko Inaba Masamichi Kuroda Katsutoshi Arai Masaru Murakami 《Fisheries Science》2017,83(5):743-756
Repetitive DNA sequences, ManDra and ManBgl, were isolated from the DraI and BglII digests of the genomic DNA of Misgurnus anguillicaudatus, respectively. A primer set of ManDra distinguished two genetically different groups (A and B) of M. anguillicaudatus by specific electrophoretograms. A primer set of ManBgl amplified the DNA of M. anguillicaudatus and M. mizolepis. The individuals of M. anguillicaudatus were divided into two groups depending on the fragment sizes, in which the groups A and B (B-1 and B-2) showed 400 and 460 bp, respectively. M. mizolepis was distinguished by a different pattern (400-, 460-, and 510-bp fragments). PCR–RFLP analyses of recombination activating gene 1 gave a clear difference between A or B-2 (443-bp fragment) and B-1 groups (296- and 147-bp fragments). Clonal lineages and hybrids between B-1 and B-2 groups could be identified by appearance of three fragments (443, 296, and 147 bp). The combined analyses using the above three nuclear markers discriminated among nuclear genomes of genetic groups (A, B-1 and B-2) of M. anguillicaudatus and M. mizolepis. In several localities, natural hybridizations between the group B-1 and B-2 loaches and introgressions of clonal mitochondrial genomes into the group B-1 loaches were detected. 相似文献
987.
Wen Jye Mok Manabu Seoka Yasuyuki Tsukamasa Ken-ichi Kawasaki Masashi Ando 《Fisheries Science》2011,77(5):823-828
In the present study, we assessed small fishes as potential feed fishes with the lowest mercury levels. The mercury levels
of four small pelagic fishes and a benthic fish from the Pacific Ocean and the Sea of Japan, i.e., spotted chub mackerel Scomber australasicus, chub mackerel Scomber japonicus, horse mackerel Trachurus trachurus, round scad Decapterus punctatus, and bastard halibut Paralichthys olivaceus, were determined. Total mercury levels in fish muscle were measured using a reduction vaporizing atomic absorption method.
There were no significant correlations between body weight and mercury levels for these species. However, significant differences
were observed in the mercury levels of these species between the two catch locations, with fish caught in the Pacific Ocean
having higher mercury levels. This difference may be due to the Pacific Ring of Fire, a highly seismically and volcanically
active zone, which is located in the Pacific Ocean. Preference for these fishes for use in aquaculture should refer to the
area where they are caught in addition to the species. 相似文献
988.
989.
Roy Bimol Chandra Ando Masashi Nakatani Masahiro Okada Tokihiko Sawada Yoshifumi Itoh Tomohiro Tsukamasa Yasuyuki 《Fisheries Science》2012,78(2):471-483
Following the successful development of Pacific bluefin tuna (PBT) aquaculture, it is of considerable importance to determine
the muscle fiber types and their growth patterns for future development. Muscle fiber profiles of dorsal ordinary, lateral
ordinary (LO) and dark muscles and their growth patterns in PBT from 3.0 to 54.3 kg body weight were studied. Muscle fibers
were histochemically stained for NADH-diaphorase and myosin adenosine triphosphatase activity (mATPase), and immunohistochemically
stained with S-58 slow-muscle myosin antibody. All muscle fibers in dorsal and LO muscles showed low NADH-diaphorase activity,
and acid-labile (pH 4.0 or 4.3) and alkali-stable mATPase activity. In LO muscle adjacent to dark muscle, three intensities
of mATPase activity were observed after acid pre-incubation at pH 4.5 or 5.0, and the activity was related to the muscle fiber
diameter. In dark muscle, all small and some large fibers stained intensely for NADH-diaphorase activity, related to their
high aerobic metabolism. The high-active fibers with NADH-diaphorase in dark muscle were positive for S-58 antibody. Some
large fibers in dark muscle showed intermediate NADH-diaphorase activity and high mATPase activity after alkali pre-incubations.
These are fast-twitch oxido-glycolytic fibers in dark muscle and transformed to red muscle fibers with increasing body weight. 相似文献
990.
Hideaki Yamada Atsushi Nanami Itaru Ohta Kouki Fukuoka Taku Sato Masato Kobayashi Narisato Hirai Masayuki Chimura Yuichi Akita Yuuki Kawabata 《Fisheries Science》2012,78(4):809-818
The recruitment patterns of black-spot tuskfish Choerodon schoenleinii were compared with those of orange-dotted tuskfish (OT) C. ancholago. Individuals at the settlement and juvenile stages were collected using a push net in the intertidal zone and a seine net in seagrass beds. Relative values of standard length to total length (TL) for the two Choerodon species indicated an inflection point at approximately 10?C20?mm TL, suggesting that both species complete metamorphosis at a similar size. However, their temporal and spatial occurrence patterns were distinct. Newly settled individuals (postflexion stage) of black-spot tuskfish were collected mainly within foliage of Sargassum plants of the intertidal zone around March?CApril, while those of OT occurred in both the intertidal zone and seagrass beds mainly in May and June. In seagrass beds, the abundances of both species increased from May or June; however, the TL of black-spot tuskfish was bigger than that of OT. Therefore, black-spot tuskfish progressively migrate to seagrass beds after settling and completing metamorphosis in the intertidal zone, indicating that they utilize two different habitats as nursery grounds. Early spawning and migration from the intertidal zone by this species contributed to the occurrence of relatively large individuals in seagrass beds. 相似文献