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281.
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283.
To establish a relation between biologically effective erythemal radiation (EER) and global solar radiation, the hourly and
daily clear-sky broadband (310–2,800 nm) global solar radiation (G) and spectral ultraviolet radiation incident on a horizontal
surface at Esfahan, Iran (32°37′N, 51°40′E) were measured during the period 2001–2005. Good correlations at statistically
significant levels between the daily values of EER and the daily G were found. The seasonal variability of EER/G is also discussed
and the correction factors are determined for inclusion of vertical column ozone and solar zenith angle (SZA) cycles. The
comparison of the estimated daily EER against the independent observed EER revealed that under clear sky conditions the estimations
are accurate to 10% or better over SZA of 10–60° and column ozone of 250–350 Dobson. The comparison of the results with the
similar works that have used shorter period of experimental data showed more accurate estimates. The deduced relations could
be used to a rough estimate of the daily EER from G in arid climate regions, where there is no measured UV radiation or there
are instrumental and other difficulties encountered in measuring UV radiation. 相似文献
284.
Linear-dichroism spectra of Anacystis nidulans at 77 K were determined for whole cells chemically fixed in light State 1 and light State 2. Whole cells were oriented by the squeezed gel technique using 5% gelatin 2.2 M sucrose gels. Peaks with positive dichroism were observed at 638 nm and 688 nm with shoulders at approx. 650 nm and 700 nm. The amplitude of the 650 nm shoulder was greater for cells in State 2 than those in State 1, and the State-2-minus-State 1 difference spectrum had a single peak at 656 nm. The linear dichroism spectrum of phycobilisomes isolated from A. nidulans showed peaks at 635 nm (phycocyanin) and 656 nm (allophycocyanin). The spectrum for thylakoid membranes free of phycobilisomes had one peak at 685 nm with a shoulder at 698 nm. We suggest that the change in dichroism at 656 nm between cells in State 1 and State 2 results from a change in orientation of the allophycocyanin core of the phycobilisome. This result is discussed in the context of our model for the light-state transition in phycobilisome-containing organisms. 相似文献
285.
Miho Inoue Akiko Takenaka Shoji Tanaka Ryo Kominami Osamu Takenaka 《Primates; journal of primatology》1990,31(4):563-570
Recently developed DNA fingerprinting techniques employing “minisatellite” hypervariable regions of DNA proved useful for
investigating male reproductive success in Japanese macaques (Macaca fuscata), for which other conventional behavioral or biochemical methods were impracticable. The identified paternity in a captive
group indicated that inbreeding was avoided within the same maternal lineage and that females did not tend to give birth to
offspring fathered by the same males during their life. It also revealed the possibility of a correlation between male dominance
rank and number of offspring. 相似文献
286.
S. Halle 《Oecologia》1988,75(3):451-455
Summary Pellets of diurnal avian predators (mainly kestrels and buzzards) were analysed to prove the hypothesis of selective predation for a mixed population of small rodents. It was found that voles heavily predominated as prey over mice (up to a factor of 19 during winter). Within both prey species, predation focussed on distinct parts of the populations: during winter the heaviest specimens were preferentially captured, during summer the subadults were in an exposed position. In the voles, an additional predominance of males occurred (up to a factor of 5.2 during summer). These findings verify the assumption of Errington (1956) that speciments of a low social rank are susceptible to the highest risk of predation. 相似文献
287.
288.
Silvia Giovanelli Marinella De Leo Claudio Cervelli Barbara Ruffoni Daniela Ciccarelli Luisa Pistelli 《化学与生物多样性》2018,15(5)
Helichrysum genus consists of about 600 species widespread throughout the world, especially in South Africa and in the Mediterranean area. In this study the aroma profile (HS‐SPME) and the EO compositions of seven Helichrysum species (H. cymosum, H. odoratissimum, H. petiolare, H. fontanesii, H. saxatile, H. sanguineum, and H. tenax) were evaluated. All the plants were grown in Italy under the same growth conditions. The volatile constituents, particularly monoterpenes, depended by the plant's genotype and ecological adaptation. This study represents the first headspace evaluation on the selected plants and the results evidenced that monoterpenes represented the main class of constituents in five of the seven species analysed (from 59.2% to 95.0%). The higher content in sesquiterpene hydrocarbons was observed in the Mediterranean species of H. sanguineum (68.0%). Only H. saxatile showed relative similar abundance of monoterpenes and sesquiterpene hydrocarbons. The essential oil composition of the majority of examined species are characterised by high percentage of sesquiterpenes (especially β‐caryophyllene and δ‐cadinene) ranging from 51.3% to 92.0%, except for H. cymosum, H. tenax, and H. sanguineum leaves where monoterpenes predominated (from 51.7% to 74.7%). 相似文献
289.
PurposeInterlaced beams have previously been proposed for delivering proton grid therapy. This study aims to assess dose-averaged LET (LETd) and RBE-weighted dose (DRBE) distributions of such beam geometries, and compare them with conventional intensity modulated proton therapy (IMPT).MethodsIMPT plans and four different interlaced proton grid therapy plans were generated for five patient cases (esophagus, lung, liver, prostate, anus). The constant RBE = 1.1 was assumed for optimization. The LETd was subsequently Monte Carlo calculated for each plan and used as input for two LET-dependent variable RBE models. The fulfilment of clinical goals, along with DVH and spatial distribution evaluations, were then assessed and compared.ResultsAll plans fulfilled the clinical target goals assuming RBE = 1.1. The target coverage was slightly compromised for some grid plans when assuming the variable RBE models. All IMPT plans, and 18 of 20 grid plans, fulfilled all clinical goals for the organs at risk when assuming RBE = 1.1, whereas most plans failed at least one goal when assuming the variable RBE models. Compared with the IMPT plans, the grid plans demonstrated substantially different LETd distributions due to the fundamentally different beam geometries. However, DRBE distributions in the target were similar.ConclusionsDespite the unconventional beam geometries of interlaced proton grid plans, with resulting alternating dose and LETd patterns, the fulfillment of realistic clinical goals seems to be comparable to regular IMPT plans, both assuming RBE = 1.1 and variable RBE models. In addition, the alternating grid patterns do not seem to give rise to unexpected DRBE hot-spots. 相似文献
290.