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201.
R. R. Paul J. Chatterjee A. K. Das S. K. Dutta D. Roy 《Biological trace element research》1996,54(3):213-230
Oral Submucous Fibrosis (OSF) is a precancerous condition of oral cavity and oropharynx. Its etiopathogenesis is still obscure.
Epithelial dysplasia is considered an important indicator of it. In the present study, the authors try to ascertain bioinorganic
parameters as alternate indicators of malignant potential of OSF along with other clinicopathological attributes. They also
try to identify causative factors. Thirty-six OSF patients, showing different degrees of epithelial dysplasia, and 12 normal
individuals are studied with special reference to trace metal contents (Zn and Fe) in oral tissues. Statistical analyses of
data indicate that trace metal contents can be regarded as an alternate indicator of the precancerous nature of OSF. Some
clinicopathological attributes that are easier and cheaper to measure may also indicate OSF. 相似文献
202.
Medicinal plants described in the Indian “Ayurvedic” literature viz. Tulsi (Ocimum sanctum), Gulvel (Tinospora cardifolia), bitter Neem (Azadirachta indica), Kanher (Nerium Åndicum), Vekhand (Acorus calamus), and Peacock's feather (ash) were analyzed for minor and trace elements by instrumental neutron activation analysis. The samples and the standards from the National Institute of Standards and Technology, USA and IAEA, Vienna were irradiated for 5 min, 1 h, 5 h, and 10 h with thermal neutrons at a flux of 1012–1013 n cm?2s?1 in APSARA and CIRUS reactor at BARC Bombay. High resolution γ ray spectrometry was performed using a 45 cm3 HPGe detector and a 4096 MCA system. Concentrations of 13 elements were determined. Zinc, manganese, and sodium were significantly higher in Tulsi leaves while zinc is higher in Neem leaves. Peacock's feathers were found to be rich in manganese, iron, copper, and zinc. A high concentration of mercury was also found in the peacock's feather ash. The therapeutic significance in restoring ionic balance is discussed. 相似文献
203.
Cu, Zn, Cd and Pb have been analysed in suspendedmatter and water samples from the Scheldt estuary,collected during five cruises
between May 1982 and May1983. In order to evaluate the overall metal behaviourin the estuary, continuous longitudinal profiles
ofthe total, the particulate and the dissolved metalconcentrations are discussed in relation to variousspecific physico-chemical
parameters. By means ofcorrelation and multi-regression techniques, severalestuarine processes could be identified which dominateand/or
control the behaviour of the individual tracemetals in three distinct areas of the Scheldt estuary.
The behaviour of the four selected metals was foundto show some common features, but is besides this alsocharacterised by
many individual and specificproperties. The total metal concentrations seem toco-vary well with the turbidity in the maximumturbidity
zone between salinities 2 and 10 psu. In thedownstream area a dilution profile is observed for thetotal metal concentrations
of Cu and Cd as well as forthe dissolved concentrations of all metals.
Dissolved metal production rates are high for Cu andCd, but much lower for Zn and Pb, confirming thedifferent longitudinal
dissolved metal profiles. ForCu and Cd these dissolved metal profiles arecharacterised by a broad mobilisation area, coveringthe
whole middle estuary. Pb on the other hand, showsa more confined mobilisation area, and for Zn no sucharea was found. During
winter the dissolved metalproduction rates seem to be controlled, predominantly,by desorption processes. During summer dissolved
metalproduction is correlated mainly to the dissolvedoxygen content, suggesting the domination of redoxprocesses solely or
in combination with desorptionprocesses. In some cases, co-existent with nearly zerooxygen concentrations, removal of dissolved
metals wasobserved, possibly reflecting precipitation reactions.
Longitudinal particulate metal profiles all show anegative deviation versus the dilution profile. Cu andCd provide the higher
deviations, characterised by anarrow enrichment zone preceding a broad mobilisationarea. Finally, all particulate metal profiles
appearedto correlate well with POC, when expressed involumetric units.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
204.
Maeda-Martínez Alejandro M. Belk Denton Obregón-Barboza Hortencia Dumont Henri J. 《Hydrobiologia》1997,366(1-3):45-62
Cu, Cd, Zn and Pb concentrations in both dissolved andparticulate phase were assessed during 1995. DataQuality Assurance was
an integral part of this studyand involved all major steps of the analysis proceduresuch as sampling, sample handling, preconcentrationand
determination.
Desorption and redox processes clearly control thedissolved Cu and Cd profiles. Mobilisation ofdissolved Zn is small and essentially
restricted tothe low salinity area and the late spring survey.Dissolved Pb shows the clearest dilution pattern. Theparameters
representative of these processes(dissolved oxygen and salinity) also correlate verywell with the particulate metal profiles.
In addition, the plankton activity (expressed by thechlorophyll-a levels) may influence the dissolved andparticulate metal
profiles. In combination withdesorption and redox processes, seasonal variationswere induced.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
205.
Lida Xing Hao Ran Cecilia A. Pirrone Eric M. Roberts Jianping Zhang 《Historical Biology》2016,28(8):1108-1117
We report the oldest fossil evidence of osteophagia by terrestrial invertebrates on both the Asian and African continents. Bones attributable to the Middle Jurassic dinosaur Chuanjiesaurus (Dinosauria: Sauropoda) were found with post-mortem insect modification in the Chuanjie Formation, Yunnan Province, China. The morphology of the borings closely matches the ichnogenus Cubiculum. Based on the lack of bioglyphs observed in Cubiculum ornatus, a new ichnospecies is proposed here. The new trace fossil, Cubiculum inornatus isp. nov., is interpreted to have been constructed for pupation by an unknown taxon of insect. Additionally, we report even older borings from Early Jurassic dinosaur bones of the Elliott Formation in the Karoo Basin, which represent the second oldest occurrence of insect traces in bone from continental settings. Both trace fossils sites have palaeogeographic implications for the origins and dispersal of osteophagia amongst terrestrial invertebrates during the Mesozoic. These discoveries push back the antiquity of pupation in animal bones by more than 100 million years to the Middle Jurassic, indicating that this behaviour, and osteophagy more generally, originated early in the Mesozoic, roughly comparable with the origination of insect pupation in woody substrates (Late Triassic). 相似文献
206.
Sol Noetinger Mercedes Di Pasquo Peter Isaacson Guillermo Aceñolaza María del Milagro Vergel 《Historical Biology》2016,28(7):913-929
The Devonian System in northern Argentina has been broadly analysed, but details of its lithologies, biostratigraphy and fossil content have not been presented in a comprehensive study. We performed the first integrative analysis of the palynological and macrofossil content from the Pescado Formation at the Zenta Range, Argentina. We define a new species of cryptospore and extend the stratigraphic record of the ichnogenus Psammichnites isp. for South America. The stratigraphic ranges of the palynomorphs suggest a time span from the ?late Lochkovian to Pragian–earliest Emsian, but the co-occurrences of key invertebrates narrow the age of the beds to the late Pragian and early Emsian. Moreover, sedimentary analysis indicates a proximal shoreface–foreshore depocenter during this time range for the Zenta region. The contraction phase of the basin during the middle Pragian and Emsian is evidenced by the presence of sand bodies at the top of the column and the higher supply of terrigenous components. During this regression event, a low diversity Malvinokaffric Realm brachiopod assemblage occurs, with dominance of Australospirifer hawkinsi. The predominance of the latter species during this event is coeval with the first decline of the Malvinokaffric Realm in the neighbouring Paraná basin. 相似文献
207.
Nga T. Nguyen Samuel A. McInturf David G. Mendoza-Cózatl 《Journal of visualized experiments : JoVE》2016,(113)
Hydroponic systems have been utilized as one of the standard methods for plant biology research and are also used in commercial production for several crops, including lettuce and tomato. Within the plant research community, numerous hydroponic systems have been designed to study plant responses to biotic and abiotic stresses. Here we present a hydroponic protocol that can be easily implemented in laboratories interested in pursuing studies on plant mineral nutrition.This protocol describes the hydroponic system set up in detail and the preparation of plant material for successful experiments. Most of the materials described in this protocol can be found outside scientific supply companies, making the set up for hydroponic experiments less expensive and convenient.The use of a hydroponic growth system is most advantageous in situations where the nutrient media need to be well controlled and when intact roots need to be harvested for downstream applications. We also demonstrate how nutrient concentrations can be modified to induce plant responses to both essential nutrients and toxic non-essential elements. 相似文献
208.
The ultrastructure and metal-containing inclusions of mature cell types in the hepatopancreas of a crayfish 总被引:1,自引:0,他引:1
The ultrastructure of the hepatopancreas of the crayfish Austropotamobius pallipes (Lereboullet) is described in relation to its function in digestion. X-ray microprobe analyses of the cells of this tissue have been obtained after using a variety of fixatives and plasma oxygen etching. The distribution of metals in the digestive cells is considered in relation to the polarization of the cells and their ability to absorb materials across the apical and basal cell membranes. 相似文献
209.
The central nervous system (CNS) should be especially sensitive to disturbances in trace element concentrations because of
its high metabolic rate and low capacity for regeneration. Comparatively few studies have been made on trace elements in the
CNS, which prompted us to begin a study of trace elements in four different brain lobes of the CNS, as well as in the spinal
cord. Samples were obtained at autopsy and handled carefully in order to avoid contamination. They were freeze-dried and sealed
in quartz tubes that were irradiated in a nuclear reactor. A simple chemical separation into six fractions was performed.
The gamma spectra for these fractions was registered using a Ge(Li) detector and a computerized multichannel analyzer. Results
for the following elements were obtained: Ca, Cd, Co, Cr, Cs, Cu, Fe, Rb, Se, and Zn, as well as for Na and K (not reported).
Other elements were also detected in some samples. Using this technique, brain samples from ten patients with Alzheimer’s
disease and ten control cases were examined. 相似文献
210.
Rivelli AR De Maria S Puschenreiter M Gherbin P 《International journal of phytoremediation》2012,14(4):320-334
We investigated the effects on physiological response, trace elements and nutrients accumulation of sunflower plants grown in soil contaminated with: 5 mg kg(-1) of Cd; 5 and 300 mg kg(-1) of Cd and Zn, respectively; 5, 300, and 400 mg kg(-1) of Cd, Zn, and Cu, respectively. Contaminants applied did not produce large effects on growth, except in Cd-Zn-Cu treatment in which leaf area and total dry matter were reduced, by 15%. The contamination with Cd alone did not affect neither growth nor physiological parameters, despite considerable amounts of Cd accumulated in roots and older leaves, with a high bioconcentration factor from soil to plant. By adding Zn and then Cu to Cd in soil, significant were the toxic effects on chlorophyll content and water relations due to greater accumulation of trace elements in tissues, with imbalances in nutrients uptake. Highly significant was the interaction between shoot elements concentration (Cd, Zn, Cu, Fe, Mg, K, Ca) and treatments. Heavy metals concentrations in roots always exceeded those in stem and leaves, with a lower translocation from roots to shoots, suggesting a strategy of sunflower to compartmentalise the potentially toxic elements in physiologically less active parts in order to preserve younger tissues. 相似文献