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171.
Food distribution and predation pressure are considered to be the main ecological factors that influence the use of forest strata (basically arboreality vs. terrestriality) in non-human primates. Here, we investigate ground use of wild, unprovisioned black-and-white snub-nosed monkeys Rhinopithecus bieti by means of the scan sampling method. The results show that the monkeys spent 15.0% of the day time on the ground; 16.6%, 12.7%, and 15.6% for adult males, adult females and juveniles, respectively. Adult males and juveniles of both sexes showed significantly higher rates of terrestrial time than adult females. Females without clinging infants spent significantly more time on the ground than expected, while females with clinging infants spent significantly less time on the ground than expected. These results suggest that the higher degree of terrestrial behavior for males and juveniles may be due to their higher agility in comparison with females. Our study showed that the monkeys fed more on lichens relative to other food items when in the trees, but more on buds/leaves, flowers, fruits/nuts, resin/bark, and herbs when on the ground. According to our investigation, the ecological significance of the species' terrestriality lies mainly in the utilization of terrestrial food resources [ Current Zoology 55 (3) : 180 - 187, 2009]. 相似文献
172.
I. G. Syasina 《Russian Journal of Marine Biology》2003,29(1):23-30
The content of persistent organochlorine pesticides (DDT and its metabolites, -, - and -isomers of hexachlorocyclohexane, HCH) were studied in the tissues and organs of some fish and molluskan species from the lower reaches of the Tumen River and the contiguous part of Peter the Great Bay (Sivuchya Bay and Zapadnaya Bay of the Furugelm Isl.) and Amursky bay. The highest total content of HCHs (785.60 ng/g of gross mass) was revealed in the digestive gland of the Japanese scallop Mizuhopecten yessoensis from Zapadnaya Bay and in the brain and the liver of the starry flounder Platichthys stellatus from the Tumen River (390.80 and 340.29 ng/g of gross mass). The maximum total content of DDT (270.70 ng/g of gross mass) was recorded in the brain of the dark plaice Pleuronectes obscurus from Zapadnaya Bay and in the liver of the far eastern smooth flounder Pleuronectes pinnifasciatus, caught in Amursky Bay to the west of Skrebtsov Isl. (212.80 ng/g of gross mass). The level of HCHs and DDT in mollusks and flounders from Zapadnaya Bay was higher than that in the same species from Sivuchya Bay. The concentration of organochlorine pesticides (OCP) in P. pinnifasciatus from the inner part of Amursky Bay at Skrebtsov Isl. was higher than in individuals of that species from the open part of the Bay at Peschany Pen. The DDT/DDE and DDT/DDT ratios evidenced the recent entry of DDT into the ecosystem of Peter the Great Bay. The southwest part of Peter the Great Bay, from the mouth of the Tumen River up to Furugelm Isl, was contaminated by HCHs to a greater extent than Amursky Bay. OCPs accumulated in appreciable quantities in the organs of fishes and mollusks of Peter the Great Bay, though their present content does not exceed sanitary–hygienic standards, a subsequent monitoring of their concentrations in biota is necessary. 相似文献
173.
Penelope Hollick Tissa Senaratna Jen McComb Eric Bunn Kingsley Dixon 《Plant Growth Regulation》2002,36(1):31-39
The effects of the triazole compound paclobutrazol on the mycorrhizalfungi and production of droppers (tuber stalks) in three species of terrestrialorchids of southwestern Australia were investigated. Seedlings ofDiuris laxiflora Lindley (bee orchid), Microtismedia R. Br. (common mignonette orchid), and Pterostylissanguinea D. Jones & M. Clements (dark banded greenhood orchid)were cultured symbiotically with specific mycorrhizal fungi invitro. The mycorrhizal fungi of the study species were grown on mediacontaining paclobutrazol at 0, 1.7, 3.4, 10.2, or 17.0 M(corresponding to 0, 0.5, 1.0, 3.0, or 5.0 mgL–1). Paclobutrazol at all concentrations evaluateddecreased the growth rates of the mycorrhizal fungi of M.media and P. sanguinea below that of thecontrol. However, paclobutrazol did not adversely affect the growth of themycorrhizal fungus of D. laxiflora, and low concentrations(1.7 or 3.4 M) stimulated the growth of this fungus. Symbiotic seedlings of the study species were exposed to paclobutrazolat 0, 1.7, 3.4, 10.2, or 17.0 M. Paclobutrazol at allconcentrations evaluated increased dropper (tuber stalk) production inD. laxiflora, but had no effect on M.media and P. sanguinea.This suggests that, for species in which paclobutrazol has no fungicidaleffect on mycorrhizal fungi, it has the potential to stimulate early andefficient tuberization of symbiotic orchid seedlings. 相似文献
174.
To better understand carbon (C) cycling in arctic tundra we measureddissolved C production and export rates in mesocosms of three tundra vegetationtypes: tussock, inter-tussock and wet sedge. Three flushing frequencies wereused to simulate storm events and determine potential mass export of dissolved Cunder increased soil water flow scenarios. Dissolved C production and exportrates differed between vegetation types (inter-tussock < tussock < wetsedge). In the absence of flushing, dissolved organic C (DOC) dominatedproduction in tussock and inter-tussock soils but was consumed in wet sedgesoils (8.3, 32.7, and –0.4 g C g soil–1day–1). Soil water dissolved C concentrations declined over time when flushedat high and medium frequencies but were variable at low flushing frequency.Total yield of dissolved C and DOC increased with increased flushing frequency.The ratio of DOC to dissolved inorganic C exported dropped with increasedflushing under tussock but not inter-tussock or wet sedge vegetation. Massexport per liter of water added declined as flushing frequency increased intussock and inter-tussock mesocosms. Export and production of dissolved C werestrongly correlated with above ground biomass, but not with photosynthetic ratesor below ground biomass. DOC quality was examined by measuring production ofToolik Lake bacteria fed mesocosm soil water. When normalized for DOCconcentration, wet sedge soil water supported significantly higher bacterialproduction. Our results indicate that arctic tundra soils have high potentialsfor dissolved C export, that water flow and vegetation type mainly controldissolved C export, and that responses of aquatic microbes to terrestrial inputsdepend on the vegetation type in the watershed. 相似文献
175.
Cutting straight line transects through dense forest is time consuming and expensive when large areas need to be surveyed for rare or highly clustered species. We argue that existing paths or game trails may be suitable as transects for line transect sampling even though they will not, in general, run straight. Formulas and software currently used to estimate local density using perpendicular distance data can be used with closest approach distances measured from curving transects. Suitable paths or trails are those for which the minimum radius of curvature is rarely less than the width of the shoulder in the detection probability function. The use of existing paths carries the risk of bias resulting from unrepresentative sampling of available habitats, and this must be weighed against the increase in coverage available. 相似文献
176.
Christina?J.?CampbellEmail author Filippo?Aureli Colin?A.?Chapman Gabriel?Ramos-Fernández Kim?Matthews Sabrina?E.?Russo Scott?Suarez Laura?Vick 《International journal of primatology》2005,26(5):1039-1051
Spider monkeys (Ateles spp.) are well known for their highly arboreal lifestyle, spending much of their time in the highest levels of the canopy
and rarely venturing to the ground. To investigate terrestriality by Ateles and to illuminate the conditions under which spider monkeys venture to the ground, we analyzed ad libitum data from 5 study sites, covering 2 species and 5 subspecies. Three of the sites are in Central/North America: Barro Colorado
Island (BCI), Panama (Ateles geoffroyi panamensis), Santa Rosa National Park, Costa Rica (A. g. frontatus), and Punta Laguna, Mexico (A. g. yucatanensis). The 2 remaining sites are in South America: Cocha Cashu Biological Station, Perú (A. belzebuth chamek) and Yasuni National Park, Ecuador (A. b. belzebuth). Terrestrialism by Ateles at all sites is rare; however, it is more restricted at the 2 South American sites. In South America, ground use only occurred
in the contexts of eating soil or rotten wood and visiting salt licks. In contrast at the 3 sites with Ateles geoffroyi it rarely occurred in a feeding context, but instead more frequently while drinking from streams during the dry season, by
adult females escaping attack by adult males, and as part of a chase game. In addition, on BCI adult males were on the ground
before attacking adult females. We discuss potential explanations, e.g., climate, species differences, predation pressure,
for the differences between the Central/North and South American observations. 相似文献
177.
The heart rate (HR) was studied applying noninvasive monitoring in the blue mussel Mytilus edulis L. from the White Sea. It was shown that the sublittoral mussels had a higher cardiac activity than the littoral mussels. Mollusks responded to a drop in salinity from 25 to 15‰ with a decrease in HR, which was more pronounced in sublittoral individuals. Acclimated mollusks sharply increased their HR upon being returned to the initial salinity (deacclimation). The cardiac activity normalized completely within two days after the beginning of the deacclimation. 相似文献
178.
González-Acuña D Beldoménico PM Venzal JM Fabry M Keirans JE Guglielmone AA 《Experimental & applied acarology》2005,35(4):335-339
Ticks exotic for the Neotropical region were found on Python regius imported into Argentina and Chile. All ticks (7 males and 3 females) were classified as Amblyomma latum Koch, 1844 ( = Aponomma latum). Additionally, four lots comprising 18 males of the Argentinean tortoise tick, Amblyomma argentinae Neumann, 1904, were found on a terrestrial tortoise, Chelonoidis chilensis, and on three terrestrial tortoises (probably C. chilensis) imported to Uruguay presumably from Argentina). These findings alert us to the risk of expanding the distribution of reptile parasites and their diseases into regions previously free of these parasites. 相似文献
179.
Sperm ultrastructure was studied in two Atlantic species of bivalve mollusks Geukensia demissa and Modiolus modiolus (Mytilidae). These spermatozoa have a classic structure common for species with external fertilization: the head of the spermatozoon of G. demissa and M. modiolus consists of an acrosome, including an acrosomal vesicle and periacrosomal material, a nucleus, and a middle part with two mutually perpendicular centrioles, surrounded by a ring of spherical mitochondria. The spermatozoa of G. demissa and M. modiolus differ in the general shape and size of the head (M. modiolus, 5.8 × 4 m; G. demissa, 4.2 × 2.5 m), as well as the structure of the acrosome and the number of mitochondria (M. modiolus, 8–12; G. demissa, 5–6). The spermatozoa of the Atlantic species M. modiolus and M. modiolus (M. kurilensis) from the Sea of Japan are close in ultrastructure, but differ in the number of mitochondria. This could possibly be a reason to consider M. modiolus from the Sea of Japan as a separate subspecies, M. modiolus kurilensis. In ultrastructure, the spermatozoa of G. demissa differ significantly from the spermatozoa of M. modiolus, but are similar to the spermatozoa of species of the genus Brachidontes. 相似文献
180.
NANCY BECKVAR SUSAN M. KIDWELL 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1988,21(3):257-270
Richly fossiliferous marine sediments exposed along the Sonoran coastline of the Gulf of California near Punta Chueca provide an excellent setting in which to test (a) the strength of the association of skeletal concentrations with sedimentary hiatuses, (b) the utility of taphonomic evidence for reconstructing detailed histories of those non-depositional episodes, and thus (c) the largely unexploited potential of skeletal concentrations in the identification and interpretation of lithologically obscure unconformities and condensed sequences in shallow marine deposits. Sequence analysis based on discontinuity surfaces is possible in the complex, alluvial fan-to-shallow marine transition at Punta Chueca despite rapid facies changes. Progradation of depositional sequences that contain cobbles reworked from older terrace deposits indicates accumulation during a fall in eustatic sea level. The supratidal to subtidal conglomerates and sands contain a variety of predominantly molluscan shell concentrations that, on the basis of postmortem histories of shells, formed during periods of low net sedimentation (i.e. depositional hiatuses); the majority of these shell beds lie along discontinuity surfaces identified by independent physical stratigraphic evidence. Although not all discontinuity surfaces in the terrace are paved by shell material. and not all relative concentrations of shells indicate distinct discontinuities, the strength of the association between skeletal concentrations and stratigraphic hiatuses reveals the high degree of control on fossil occurrence by sedimentation rates, and indicates that skeletal concentrations can provide good clues to stratigraphically significant surfaces. Moreover, the detailed dynamics of non-depositional episodes are reliably revealed by taphonomic analysis of the associated fossil assemblages, improving interpretations of non-depositional episodes in local sedimentary history. 相似文献