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93.
Carl W. Erkenbrecher L.Harold Stevenson 《Journal of experimental marine biology and ecology》1980,48(3):253-261
The temporal distribution of chlorophyll a and pheophytin at a transect monitoring the flow at a high-marsh creek was investigated. The observed fluctuations in chlorophyll a concentration consisted of complex, superimposed, tidal and diel rhythms; pheophytin variability, on the other hand, was controlled by the tides. Transport measurements and correlation analyses supported the hypothesis that tidal forces have a major influence on the temporal fluctuation of chlorophyll a and phaeophytin concentrations in high-marsh creeks. The data indicate that it is important to consider tidal flux when designing programs to study seasonal effects, primary productivity, and phytoplankton species composition. 相似文献
94.
The distribution, fluctuation, and short-term transport of total microbial biomass (measured as adenosine 5'-triphosphate [ATP]) was investigated in a large salt marsh creek. Hourly samples were collected synoptically for 25 h from 10 boats positioned across the 320-m width of the creek. Samples were collected from three depths ranging from 0.2 to 8.0 m. Hourly data obtained from each station were graphed, plotting depth against ATP. Subsequently, interpolated ATP values were generated for every one-tenth depth from the surface to the bottom with the use of an 11-point proportional divider. A total of 2,750 values were generated, and a mean value of 0.865 mg of ATP per m was determined. Maximum levels of ATP were found at high tide and minimal values were found at low tide. The distribution of ATP concentrations was found to be complex, with no suggestion of vertical stratification; however, horizontal divisions were apparent. ATP values corrected for direction of flow or velocity indicated two ebb-directed channels; however, when considered in total, there was a net import of ATP through the interface. The total import of ATP for this 25-h sampling period was calculated to be 3.58 kg, corresponding to a net transport of 39.8 mg of ATP per s through the cross section. Results suggest that detailed characterization of a creek transect in terms of ATP or any similar parameter requires the simultaneous measurements of both the concentration of the parameter in question and the velocity at the time and point from which the sample was taken. 相似文献
95.
R G Loy J R Buell W Stevenson D Hamm 《Journal of reproduction and fertility. Supplement》1979,(27):229-235
Sixty-two non-cycling mares were classified according to the size of largest follicles at the time of treatment with Prostalene, an analogue of prostaglandin (PG) F-2 alpha. Although oestrus occurred in only 77.4% of mares, 98.4% ovulated at an average of 6.8 days after treatment. Greatest variance of interval to ovulation was observed in mares having follicles greater than or equal to 40 mm at the time of treatment. This was due to regression of large follicles about one-third of the time and later ovulation of a succeeding follicle. This resulted also in greatest uncertainty of prediction of ovulation time based on ovarian palpation. Ninety foaling mares were given Prostalene at various days following the first ovulation post partum. Ovulation less than 6 days after treatment was strongly associated with the presence of a large follicle on the day of treatment. Otherwise most (72%) ovulations occurred 6--10 days after treatment. The distribution of interovulatory periods resulting from Prostalene on Day 6 after ovulation differed from that of Day 8 treatment. 相似文献
96.
The transport of microbial biomass and suspended material in a high-marsh creek was investigated during four 40-h tidal studies throughout the year. Although considerable differences were noted between successive tidal cycles, overall the creek was found to be an exporting system and transported a mean concentration of ATP (-33g), chlorophyll a (-66g), particulate organic carbon (-31kg), total suspended material (-344kg), and fixed suspended material (-195kg) during each tidal cycle. This net outward flux of materials was associated with a net flow of water out of creek, while the net import of aerobic, heterotrophic bacteria (43 x 10(12)) and volatile suspended material (238kg) was generally due to higher mean concentrations of these materials per unit volume of water during the flooding tide. Also the latter generally were associated with increased amounts of suspended material suggesting an association between bacteria and suspended matter. 相似文献
97.
Macrophage function in tumor-bearing mice: dissociation of phagocytic and chemotactic responsiveness 总被引:8,自引:0,他引:8
Infusion of CBA mice with lymphoid cells from the H-2 compatible but Mls-antigen incompatible C3H × CBA hybrid results in a specifically reduced capacity of the recipients lymphocytes to react in the MLC against C3H-cells. Although this reduction is immunologically specific the results of this investigation have shown that such mice exhibit a strongly reduced capacity to produce humoral antibodies against heterologous erythrocytes and a T-cell independent antigen (PVP). 相似文献
98.
All cases referred for pelvimetry in 1970-1 and all breech presentations referred for pelvimetry in 1972-4 were reviewed. Indications for pelvimetry fell into four main categories: high head in the antenatal clinic (47-8%); high head in labour (13-9%); breech presentation (20-9%); and previous caesarean section (14-8%). In the first two categories pelvimetry rarely if ever influenced management, and it should not be performed routinely. In breech presentation and cases of caesarean section pelvimetry seemed to be of value, but in the latter group it should be performed puerperally to avoid the known radiation hazard to the fetus. A fairly close correlation between obstetric conjugate and pelvic capacity was shown, which suggested that a 3400-g baby might pass through a pelvis of obstetric conjugate of 10 cm as a cephalic trial of labour, but would need an obstetric conjugate of 11-7 cm for safe vaginal breech delivery. 相似文献
99.
The experiments reported here found that judgments of burnintensity are affected by long-term memory (LTM). The implicationof these findings for range-frequency theory and the role ofLTM in intensity judgments are discussed. 相似文献
100.