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991.
Many predatory arthropods occur naturally in turfgrass, and they provide adequate control of lepidopteran pests, such as fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), and black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae). Recording predation is challenging under field conditions because predators rarely leave any evidence. Clay models were successfully employed for studying predation, and this technique is underutilized in turfgrass. Little is known about whether the characteristics of clay models, such as color, shape, and size, influence arthropod interactions in turfgrass. To improve the utility of clay models in turfgrass, the influence of the color, shape, and size of clay models on arthropod interactions was studied by exposing clay models during daytime and nighttime in a turfgrass field. The results showed that arthropods interacted with clay models, and various types of impressions were recorded, including paired marks, scratches, cuts, and pricks. Although the color of the clay model had no significant effects on arthropod interactions during the night, significantly greater numbers of impressions were noticed on the blue and green models than on the yellow models during the daytime. The caterpillar-shaped models captured significantly greater densities of impressions than the beetle-shaped models. Additionally, the number of impressions significantly increased with an increase in the size of the model regardless of shape. 相似文献
992.
993.
Shannon RR Ceccon C Smith WS Metheny W Philbrick R 《Science (New York, N.Y.)》1979,206(4424):1267-1272
An experiment has been performed to measure directly the effect of atmospheric turbulence on spherical wave propagation of light on a vertical path. The results permit determination of the magnitude of the effect at a variety of locations and under different conditions. Agreement is found with the functional form predicted by the inertial theory of turbulence. General agreement is found with scattering data obtained by a low-frequency radar and with predictions of some turbulence profile models. The results also demonstrate some reasons for poor agreement with time integrating sensors. 相似文献
994.
R.L. Blevins G.W. Thomas M.S. Smith W.W. Frye P.L. Cornelius 《Soil & Tillage Research》1983,3(2):135-146
Soil properties were evaluated after 10 years of continuous non-tilled and conventionally tilled corn (Zea mays L.) production on a Maury silt loam (Typic Paleudalfs) soil, which had been in bluegrass (Poa pratensis L.) for 50 years. On limed and nonlimed plots soil samples from 0, 84, 168 and 336 kg/ha N treatments were taken in the 0–5, 5–15 and 15–30 cm layers for determination of organic C and N, soil pH, and exchangeable Al, Mn, Ca, Mg, K.Tillage treatments had no effect on soil bulk density in the 0–15 cm layer. In the 0–5 cm surface layer, organic C and N were approximately twice as high with no-tillage as with conventional tillage; N fertilizer induced a high level of both organic C and organic N. No-tillage decreased soil pH for unlimed plots as compared to conventional tillage, especially at high N-rates, which produced an increase in exchangeable Al and Mn and a decrease in exchangeable Ca down to the 30 cm depth. When lime was applied, the pH of the surface soil was slightly higher under no-tillage. On treatments receiving lime, exchangeable Al and Mn levels were very low with no significant difference in tillage systems. At low rates of N fertilization the 10-year average corn yield was higher for conventional tillage than for no-tillage, but at high rates of N fertilization it was equal or higher for no-tillage treatments receiving lime. Unlimed no-tillage treatments produced lower yields at all N levels during 1975–1979. Deterioration of soil physical properties was not observed. 相似文献
995.
Abbott RJ Smith LC Milne RI Crawford RM Wolff K Balfour J 《Science (New York, N.Y.)》2000,289(5483):1343-1346
The arctic flora is thought to have originated during the late Tertiary, approximately 3 million years ago. Plant migration routes during colonization of the Arctic are currently unknown, and uncertainty remains over where arctic plants survived Pleistocene glaciations. A phylogenetic analysis of chloroplast DNA variation in the purple saxifrage (Saxifraga oppositifolia) indicates that this plant first occurred in the Arctic in western Beringia before it migrated east and west to achieve a circumpolar distribution. The geographical distribution of chloroplast DNA variation in the species supports the hypothesis that, during Pleistocene glaciations, some plant refugia were located in the Arctic as well as at more southern latitudes. 相似文献
996.
997.
Joseph Ku 《Crop Protection》2000,19(8-10):859-861
998.
Rajangam Udayakumar Sampath Kasthurirengan Ayyappan Vasudevan Thankaraj Salammal Mariashibu Jesudass Joseph Sahaya Rayan Chang Won Choi Andy Ganapathi Sei Chang Kim 《Plant foods for human nutrition (Dordrecht, Netherlands)》2010,65(2):91-98
The phenolic compounds and flavonoids were determined from the extracts of Withania somnifera root (WSREt) and leaf (WSLEt). The WSREt has 28.26 mg/g total phenolic compounds and 17.32 mg/g flavonoids, whereas WSLEt
has 5.4 mg/g total phenolic compounds and 5.1 mg/g flavonoids. The WSREt, WSLEt and glibenclamide were orally administered
daily to diabetic rats for 8 weeks. After the treatment, the levels of urine sugar, blood glucose, liver glycogen, and antioxidants
like vitamin C and E in plasma and superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS),
glutathione peroxidase (GPx), glutathione-S-transferase (GST) and reduced glutathione (GSH) in liver, kidney and heart were
determined. Diabetic rats showed a significant (p < 0.05) elevation in glucose and TBARS and a significant (p < 0.05) reduction in glycogen, vitamin C and E, SOD, CAT, GPx, GST, and GSH levels when compared to normal control rats. Administration
of WSREt, WSLEt and glibenclamide to diabetic rats restored the levels to normal. In the light of aforesaid facts, it is suggested
that the presence of phenolic compounds including flavonoids in W. somnifera root and leaf extracts and their antioxidant activity may play a vital role in reduction of blood glucose level in alloxan-induced
diabetic rats. 相似文献
999.
M.L. Wall H.L. Wheeler M.P. Huebsch J.C. Smith D. Figeys I. Altosaar 《Journal of Cereal Science》2010
The starch granule surface is a frontline of microbial attack and defence, operating in the background of normal starch granule metabolism. Puroindoline, a wheat protein which binds starch granule surfaces, contains a unique tryptophan-rich domain likely responsible for this property, though direct evidence is lacking. To test puroindoline’s tight association, prime starch granule extracts were water-washed 8 or 20 times and residual puroindoline removed using a solution of 50% isopropanol/50 mM NaCl. We found that this solvent was consistent in the amount of protein extracted from wheat flour and washed starch, regardless of initial protein content. Relative quantification of puroindoline following water-washing was performed using dot blot. Washing more than 8 times did not further reduce puroindoline content of starch granules suggesting a strong association with the starch granule surface. To identify the tryptophan-rich domain tightly associated with the starch granule surface, a combination of in situ tryptic digestion and mass spectrometry was used. Following digestion and water-washing, 50% isopropanol/50 mM NaCl was used to remove tightly-associated peptides for identification by mass spectrometry. Using this method, we identified the tryptophan-rich domain of puroindoline directly bound to the starch granule surface of wheat. 相似文献
1000.
Summary A numerical model has been produced to predict the distribution of deposits of the sprout suppressant isopropyl N-(3-chlorophenyl)
carbamate [CIPC] in box potato stores. The model considers the movements of the CIPC by forced convection, sedimentation,
natural convection and diffusion. Measurements have mostly shown high levels of CIPC on the top of the uppermost box, with
levels decreasing towards the floor of the store. The model predicts this pattern and indicates that particle size, the temperature
difference between the air inside and around the boxes, and the application rate of the chemical have a large effect on the
levels and uniformity of CIPC deposits. Smaller particles (2 μm) can lead to better uniformity of distribution, but they are
prone to natural convection effects which are difficult to control and they are slow to deposit which could lead to greater
losses from the store. 相似文献