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31.
The gene encoding the 49-kilodalton protein that undergoes light-induced phosphorylation in the Drosophila photoreceptor has been isolated and characterized. The encoded protein has 401 amino acid residues and a molecular mass of 44,972 daltons, and it shares approximately 42 percent amino acid sequence identity with arrestin (S-antigen), which has been proposed to quench the light-induced cascade of guanosine 3',5'-monophosphate hydrolysis in vertebrate photoreceptors. Unlike the 49-kilodalton protein, however, arrestin, which appears to bind to phosphorylated rhodopsin, has not itself been reported to undergo phosphorylation. In vitro, Ca2+ was the only agent found that would stimulate the phosphorylation of the 49-kilodalton protein. The phosphorylation of this arrestin-like protein in vivo may therefore be triggered by a Ca2+ signal that is likely to be regulated by light-activated phosphoinositide-specific phospholipase C.  相似文献   
32.
Many salmonids have become at risk of extinction. For teleosts whose eggs cannot be cryopreserved, developing techniques other than egg cryopreservation to save genetic resources is imperative. In this study, spermatogonia from rainbow trout were intraperitoneally transplanted into newly hatched sterile triploid masu salmon. Transplanted trout spermatogonia underwent spermatogenesis and oogenesis in male and female recipients, respectively. At 2 years after transplantation, triploid salmon recipients only produced trout sperm and eggs. With use of these salmon as parents, we successfully produced only donor-derived trout offspring. Thus, by transplanting cryopreserved spermatogonia into sterile xenogeneic recipients, we can generate individuals of a threatened species.  相似文献   
33.
Feline immunodeficiency virus (FIV) induces a disease similar to acquired immunodeficiency syndrome (AIDS) in cats, yet in contrast to human immunodeficiency virus (HIV), CD4 is not the viral receptor. We identified a primary receptor for FIV as CD134 (OX40), a T cell activation antigen and costimulatory molecule. CD134 expression promotes viral binding and renders cells permissive for viral entry, productive infection, and syncytium formation. Infection is CXCR4-dependent, analogous to infection with X4 strains of HIV. Thus, despite the evolutionary divergence of the feline and human lentiviruses, both viruses use receptors that target the virus to a subset of cells that are pivotal to the acquired immune response.  相似文献   
34.
A new disease was found in Japan, on celery (Apium graveolens var. dulce) having severe chlorotic leaf spot, stunt, and dwarf with leaf curl. A spore suspension from the fungus isolated from affected plants induced identical symptoms 14 days after plants were sprayed. Identification and molecular characterization showed that the causal agent is Colletotrichum simmondsii. This report is the first of stunt anthracnose on celery caused by C. simmondsii. We propose the name “stunt anthracnose” for the new disease. Colletotrichum acutatum sensu lato, as reference pathogen of celery anthracnose, should be changed to C. fioriniae based on morphological and molecular characteristics.  相似文献   
35.
Screening for brassinosteroid biosynthesis inhibitors was performed to find azole derivatives that induced dwarfism, to resemble brassinosteroid-deficient mutants in Arabidopsis, and which could be rescued by brassinosteroid. Through this screening experiment, propiconazole fungicide was selected as a likely inhibitor of brassinosteroid biosynthesis and, thus, propiconazole derivatives with optimized activity and selectivity were synthesized. The biological activity of these compounds was evaluated by examining cress stem elongation. Among the compounds tested, 2RS,4RS-1-[2-(4-trifluoromethylphenyl)-4-n-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazole (12) showed the most potent capability to retard cress stem elongation in the light. The compound-induced hypocotyl dwarfism was restored by the coapplication of 10 nM brassinolide but not by 1 microM gibberellin. These results suggest that 12 should affect brassinosteroid biosynthesis. The potency and specificity of 12 were greater than those of brassinazole, a previously reported brassinosteroid biosynthesis inhibitor.  相似文献   
36.
ABSTRACT

The fertilizer absorption characteristics of strawberries are not clear, although appropriate fertilization is definitely necessary to ensure produce quality and quantity. This study aimed to determine the amounts of macro- and micronutrients absorbed during cultivation of strawberries and their biodistribution and utilization in the plant body. We cultivated Japanese strawberries ‘Benihoppe’ and ‘Kirapika’ in small hydroponic equipment containing a nutrient solution and determined the amounts of N, P, K, Ca, Mg, Fe, Mn, B, Zn, Cu, and Mo absorbed during and at the end of cultivation. The results revealed the adsorption levels of these elements during the cultivation period. The nutrient concentrations varied greatly among plant organs. In particular, P and B accumulated at high levels in the leaves and stem, K, Ca, Mg, Mn, Zn, and Cu accumulated in the crown, and N, Fe, and Mo accumulated in the roots. In addition, the uptake levels of N, P, K, Mg, Mn, Zn, and Cu differed between Benihoppe and Kirapika. Our results provide useful information for determining fertilizer application rates in strawberry cultivation.  相似文献   
37.
A simple and rapid analytical method for strigolactones, germination stimulants for the root parasitic weeds witchweed (Striga spp.) and broomrape (Orobanche spp.), has been developed using high-performance liquid chromatography connected to tandem mass spectrometry (LC/MS/MS). The natural strigolactones (strigol, sorgolactone, orobanchol, and alectrol) were clearly separated and identified by LC/MS/MS. As low as 0.1 pg/microL of strigol and 0.5 pg/microL of sorgolactone could be quantified, whereas 1 pg/microL was needed for the quantification of orobanchol (S/N > 10). Using this method, it was found that red clover produces orobanchol and alectrol but not strigol. The roots of red clover seedlings were found to produce 13, 70, 58, and 65 pg of orobanchol/plant 1, 2, 3, and 4 weeks after germination, respectively.  相似文献   
38.
Precipitation chemistry in Japan was discussed on a wet-only sample database obtained in a nationwide survey from April 1989 to March 1993. Wet-only samples were collected at 29 stations over Japan on a biweekly basis. Commonly determined chemical parameters were measured in laboratories. The volume-weighted annual mean pH at each site ranged from 4.50 to 5.83 with a mean of 4.76. Concentration ranges and means (parenthesized) on an equivalent basis for major ions were as follows: nss-SO4 2–; 5.2–58.9 (38.6), NO3 ; 1.8–25.0 (14.1), NH4 +; 0.55–29.8 (18.3), nss-Ca2+; 2.0–34.5(14.2), Na+; 6.4–275.3 (49.1), Cl; 13.7–322.4 (63.5) eq L–1. Acid-base relationships for Phase-II records were quantitatively discussed in terms of three measures: pH, fractional acidity, and our proposed pAi.  相似文献   
39.
The extracellular proteases of Staphylococcus hyicus subsp. hyicus were assayed by a zymogram showing caseinolysis and gelatinolysis. Four bands were associated with caseinolysis or with gelatinolysis. The patterns shown by strains isolated from pigs, chickens and cows were compared; isolates from pigs differed from those isolated from chickens or cows but strains isolated from diseased and healthy pigs could not be differentiated.  相似文献   
40.
A new of performing cerebral sinus venography was developed that opacivies both the ventral and most of the dorsal venous sinus systems. A pediatric angiographic catheter was introduced into the external jugular vein and advanced to the level of the temporal sinus. Iodinated contrast medium was injected manually and radiographs were made. Subtraction radiography was used to visualize vessels field wit contast medium. Venography was simple and relatively non-invasive and was considered safe. The technique was used to confirm occlusion of the transverse venous sinus in healthy dogs that had undergone radical craniectomies.  相似文献   
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