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81.
L. A. Lacey D. H. Ross C. M. Lacey A. Inman H. T. Dulmage 《Journal of industrial microbiology & biotechnology》1988,3(1):39-47
Summary Four experimental formulations ofBacillus sphaericus Neide (2362 isolate) were evaluated for larvicidal activity against culicine and anopheline larvae in several natural and artificial habitats. A granular formulation (5% primary powder) was tested against natural populations of mosquitoes in two simulated habitats in Florida and in maturing and reflooded rice fields in Louisiana. Larvae ofCulex quinquefasciatus Say were reduced by 97 and 99% after application of the granules at the rate of 10 kg/ha to polluted tanks and 2.5 kg/ha to sod-lined potholes, respectively. Anopheline andPsorophora columbiae (Dyar and Knab) larvae were reduced by 68 and 92–100%, respectively, after application of 5 kg granules/ha to rice fields. A flowable concentrate (12.8% primary powder) applied to unpolluted and organically enriched habitats in Florida at 0.25 kg/ha reduced populations ofCulex spp. by 93–100% and 99%, respectively. Sustained-release briquets (5% primary powder) applied at the rate of one half briquet/1.8 m2 sod-lined potholes reduced larval populations ofCx. quinquefasciatus by 88–95% for up to 2 weeks in open sunlight. Sustained-release pellets (30% primary powder) applied to small woodland pools in Memphis, TN at the rate of four pellets/pool virtually eliminated larval populations ofCx. restuans Theobald for over 8 days. Variable persistance of larvicidal activity was noted for the other treatments depending on the formulation, target species and habitat. 相似文献
82.
Differences in responsiveness to potential prey and pollen were tested in the facultative predator,Euseius tularensis Congdon. Following isolation without food for 16 h, adult female mites were observed with one of the following potential foods: pollen ofMalephora crocea (Jacquin) Schwantes,Scirtothrips citri (Moulton) 2nd instar larvae,Tetranychus pacificus McGregor nymphs and ♂,Panonychus citri (McGregor) nymphs and ♂,E. hibisci (Chant) larvae, andE. tularensis larvae. Responses were compared using the proportion of encounters that resulted in consumption. This proportion was highest when pollen was encountered, followed byS. citri andT. pacificus. Consumption was much lower in response toP. citri and congeneric larvae. WhenS. citri larvae were encountered a 2nd time, 1 to 2 h after the initial capture and consumption, responsiveness increased to a level equal to the response observed with pollen. These results suggest thatE. tularensis is a more effective biological control agent of citrus thrips (S. citri) than of citrus red mite (P. citri). 相似文献
83.
Lise Stengård Hansen 《BioControl》1988,33(1):33-42
The phytoseiid miteAmblyseius barkeri (Hughes) (=Amblyseius mckenziei Sch. & Pr.) was used for biological control ofThrips tabaci Lind. in 7 commercial glasshouses with cucumber (a total of 5780 m2). Predatory mites were introduced 3–4 times in densities ranging from 40 to 300/m2 at each release. In 6 of the 7 glasshouses, control of thrips was satisfactory throughout the growing season. Thrips densities
were kept below 15 individuals per leaf. In 1 glasshouse, thrips damage was seen on the fruits at densities of 25 thrips per
leaf, but the thrips population was quickly reduced and remained at low densities for the next 3 months.
相似文献
84.
M. J. Gormally 《BioControl》1988,33(4):387-395
The effect of 5 constant temperatures (10, 14, 17, 20 and 23°C) on the oviposition and longevity ofIlione albiseta was investigated. Most eggs were laid at 14–17°C and mean oviposition period declined progressively above and below 14°C.
There was no significant difference between oviposition rates or preoviposition periods at each constant temperature, but
the mean number of days between egg laying for each female was significantly greater at 10 °C than at 17, 20 and 23 °C than
at 20 °C. The percentage of infertile eggs laid ranged from 9.2% at 23 °C to 17.9 % at 20 °C and these eggs tended to be laid
at the beginning and end of each oviposition period. A possible association between sex ratio of the emergent adult and temperature
is also discussed.
相似文献
85.
The biology of the noctuid,Tyta luctuosa (Denis & Schiffermüller) (Lep.: Noctuidae), a defoliator of field bindweed,Convolvulus arvensis L., was studied in southern Europe.T. luctuosa is widely distributed and feeds on both thick stands and scattered host populations growing in a diversity of habitats. It
undergoes 2 and perhaps a partial 3rd generation/year in southern Europe and is active during most of the growing season ofC. arvensis. In the laboratory the total time from egg to adult averages 45.6 days. There are 5 larval instars. Adult females deposit
on average over 400 eggs. The larvae being able to feed and develop on native North AmericanCalystegia spp. in the laboratory, there are some reservations about its release in North America. However, the moth has potential value
as a biological control agent for field bindeed in the western USA where it would fill an almost unoccupied niche.
相似文献
86.
J. C. Onillon 《BioControl》1988,33(4):481-494
Les problèmes posés par les ravageurs des Citrus ont pris une importance considérable au cours de ces 3 dernières décennies
et cela pour plusieurs raisons:
Le potentiel de ces ravageurs, pour la plupart plurivoltins, est souvent très important et les conditions climatiques favorables
jointes à la persistance pendant toute l'année de la frondaison assurent des niveaux de populations très élevés. 相似文献
– | - dans un 1er temps, l'on peut invoquer l'introduction accidentelle de ravageurs,Dialeurodes citri Ashm en 1945 (Pussard, 1953),Unaspis yanonensis Kuw. en 1963 (Commeau & Sola, 1964) etAleurothrix floccosus Mask. en 1967 (Onillon, 1969). Ces 3 espèces démunies de leur cortège d'ennemis naturels et trouvant dans leur nouvelle aire de répartition des conditions favorables de développement, ont très rapidement présenté d'importantes pullulations. Ces ravageurs nouveaux sont venus compléter une liste déjà longue d'une dizaine de phytophages majeurs au niveau des plantations d'agrumes du Bassin Méditerranéen; |
– | - un 2ème facteur non négligeable est présenté par un vieillissement des plantations et l'importance du co?t des méthodes culturales d'entretien qui sont comme la taille souvent négligées notamment pour les Citrus d'ornement ou de jardins familiaux. Ces facteurs ont alors pour corollaire le maintien d'arbres à frondaison dense assurant un développement optimum du ravageur; |
– | - enfin le développement d'une lutte chimique d'assurance, génératrice de déséquilibres fauniques particulièrement sensibles au niveau des acariens par élimination d'une partie de l'entomofaune prédatrice ou au niveau des cochenilles telles queAspidiotus nerii Bouché ouParlatoria pergandei Comst. par destruction de l'entomofaune parasitaire utile. |
87.
Gordon A. Fox 《Evolutionary ecology》1992,6(6):482-499
Summary Much of life history theory follows from the idea that natural selection acts on the allocation of resources to competing and independent demographic functions. This paradigm has stimulated much research on the life histories of annual plants. Models of whole-plant resource budgets that use optimal control theory predict periods of 100% vegetative and 100% reproductive growth, sometimes with periods of mixed growth. I show here that this prediction follows from the assumption of independence of the competing vegetative and reproductive compartments. The prediction is qualitatively unchanged even after relaxing important simplifying assumptions used in most models. Although it follows naturally from the assumptions of the models, this kind of allocation pattern is unlikely to occur in many plants, because it requires that (1) leaf and flower buds can never simultaneously be carbon sinks; and (2) organs that accompany flowers, such as internodes and bracts, can never be net sources of photosynthate. Thus while resources are doubtless important for annual plants, an exclusively resource-based perspective may be inadequate to understand the evolution of their life histories. Progress in research may require models that incorporate, or are at least phenomenologically consistent with, the basic developmental reles of angiosperms. 相似文献
88.
Gordon A. Fox 《Evolutionary ecology》1992,6(6):500-518
Summary Models of optimal carbon allocation schedules have influenced the way plant ecologists think about life history evolution, particularly for annual plants. The present study asks (1) how, within the framework of these models, are their predictions affected by within-season variation in mortality and carbon assimilation rates?; and (2) what are the consequences of these prediction changes for empirical tests of the models? A companion paper examines the basic assumptions of the models themselves. I conducted a series of numerical experiments with a simple carbon allocation model. Results suggest that both qualitative and quantitative predictions can sometimes be sensitive to parameter values for net assimilation rate and mortality: for some parameter values, both the time and size at onset of reproduction, as well as the number of reproductive intervals, vary considerably as a result of small variations in these parameters. For other parameter values, small variations in the parameters result in only small changes in predicted phenotype, but these have very large fitness consequences. Satisfactory empirical tests are thus likely to require much accuracy in parameter estimates. The effort required for parameter estimation imposes a practical constraint on empirical tests, making large multipopulation comparisons impractical. It may be most practical to compare the predicted and observed fitness consequences of variation in the timing of onset of reproduction. 相似文献
89.
Control and Response Coefficients of transition time have been determined in a rat liver glycolytic system under different glucose concentrations. Results have been compared with the Flux Control and Flux Response Coefficients measured in the same conditions, showing that transition time and flux are different responses of the system, subject to different regulation and control. Control Coefficients of flux and transition time show a very different profile in each condition of glucose concentration assayed. Ratio of Flux Control coefficients of glucokinase over phosphofructokinase at 5 and 20 mM glucose concentration changes from 3.2 to 0.5, while the same ratio in the case of Transition Time Control Coefficients moves from 0.6 to 0.93. Moreover, the absolute values of Transition Time Control Coefficients in glycolytic conditions are one order of magnitude bigger than in gluconeogenic conditions. Values of Response Coefficients also show that the transition time has a bigger sensitivity to changes in glucose concentration than the flux in all conditions assayed, but particularly in glycolytic ones. 相似文献
90.
Sasha N. Zill S. Faith Frazier John Lankenau Karen Jepson-Innes 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1992,170(6):761-772
Summary The use of the locust (Schistocerca americana) hindleg in postural control was examined in animals that stood on a repeatedly swayed vertical substrate. Myograms were recorded from leg muscles and the angle of the femoro-tibial joint was monitored photographically. Two discrete strategies were observed,; in compensatory reactions the hindleg was held in place, while in flexion reactions, the leg was moved, most often to complete flexion of the femoro-tibial joint. Tightly coupled, rhythmic bursting occurred in the flexor and levator muscles of the leg during compensatory reactions. Bursting was initiated repeatedly when the substrate was being pulled away from the animal. Bursting was correlated with subsequent decreases in the rate of change of the femorotibial joint angle. Compensatory and flexion reactions occurred preferentially in different ranges of joint angles: most often, compensatory reactions occurred in the midrange, while flexion reactions were elicited in the extremes of joint angle. These differences may be due to the mechanical advantages of the tibial muscles and the leg may be moved to full flexion because of a locking mechanism of the flexor muscle tendon. These reactions are compared with known reflexes of hindleg proprioceptors and contrasted with similar responses of vertebrates. 相似文献