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991.
药材甲发育起点温度和有效积温 总被引:1,自引:0,他引:1
在恒温条件下用新鲜药材甘遂饲养药材甲Stegobium paniceum(L.),测定药材甲各虫态(龄)的发育历期,结果表明,该虫卵、幼虫、蛹、产卵前期及世代发育起点温度分别是5.05,8.45,9.06,8.36和8.01℃,有效积温分别是177.9,745.5,127.9,37.8和1094.1日.度。 相似文献
992.
993.
994.
T. R. McClanahan M. Ateweberhan C. Ruiz Sebastián N. A. J. Graham S. K. Wilson J. H. Bruggemann M. M. M. Guillaume 《Coral reefs (Online)》2007,26(3):695-701
Satellite and compiled in situ observations of sea surface temperatures have greatly increased the ability to detect anomalous
and persistent warm water and are being widely used to predict climate change, coral bleaching and mortality. A field-based
synoptic view of coral bleaching spanning eight countries and ∼35° of latitude in the western Indian Ocean tested the accuracy
of synoptic temperature data derived from satellites and shipboard data to detect and predict bleaching during 2005. The ability
to predict the degree of bleaching based on degree heating weeks data was moderate, but increased when past temperature anomalies
and coral community susceptibility were included. It is estimated that slightly more than half of the bleaching response is
due to anomalous warm water and nearly half due to taxa and community level acclimation or adaptation, where these two factors
have opposing effects. Cumulative temperature anomalies do identify general areas with bleaching but both large over and underestimates
of bleaching intensity were observed. Consequently, field observations are needed to confirm the synoptic satellite predictions
for particular reefs, particularly where acclimation and reorganization of the coral community have occurred due to past bleaching
events. 相似文献
995.
Ecological forecasts predict the immigration of boreal species into Arctic waters as one consequence of rising sea temperatures.
Here, we report the finding of Atlantic snake pipefish (Entelurus aequoreus) off the western coast of Spitsbergen at 79°N in August 2006. This syngnathid fish species, which was presumed to be confined
to waters south of Iceland, has dramatically increased in population size in its core distribution area in the northeastern
Atlantic since 2002, probably in response to greater reproduction success due to higher water temperatures. We conclude that
our finding is an indication of the predicted northward extension of the distribution range of boreal species. 相似文献
996.
Diurnal variation in temperature, mental and physical performance, and tasks specifically related to football (soccer) 总被引:1,自引:0,他引:1
Reilly T Atkinson G Edwards B Waterhouse J Farrelly K Fairhurst E 《Chronobiology international》2007,24(3):507-519
Football (soccer) training and matches are scheduled at different times throughout the day. Association football involves a variety of fitness components as well as psychomotor and game-related cognitive skills. The purpose of the present research, consisting of two separate studies, was to determine whether game-related skills varied with time of day in phase with global markers of both performance and the body clock. In the first study, eight diurnally active male association football players (19.1+/-1.9 yrs of age; mean+/-SD) with 10.8+/-2.1 yrs playing experience participated. Measurements were made on different days at 08:00, 12:00, 16:00, and 20:00 h in a counterbalanced manner. Time-of-day changes in intra-aural temperature (used as a marker of the body clock), grip strength, reaction times, flexibility (markers of aspects of performance), juggling and dribbling tasks, and wall-volley test (football-specific skills) were compared. Significant (repeated measures analysis of variance, ANOVA) diurnal variations were found for body temperature (p<0.0005), choice reaction time (p<0.05), self-rated alertness (p<0.0005), fatigue (p<0.05), forward (sit-and-reach) flexibility (p<0.02), and right-hand grip strength (p<0.02), but not left-hand grip strength (p=0.40) nor whole-body (stand-and-reach) flexibility (p=0.07). Alertness was highest and fatigue lowest at 20:00 h. Football-specific skills of juggling performance showed significant diurnal variation (p<0.05, peak at 16:00 h), whereas performance on the wall-volley test tended to peak at 20:00 h and dribbling showed no time-of-day effect (p=0.55). In a second study, eight diurnally active subjects (23.0+/-0.7 yrs of age) completed five test sessions, at the same times as in the first study but with a second session at 08:00 h. Test-re-test comparisons at 08:00 h for all components indicated good reliability. Intra-aural temperature showed a significant time-of-day effect (p<0.001) with mean temperature at 16:00 h (36.4 degrees C) higher than at 08:00 h (35.4 degrees C). There was no significant effect of chronotype on the temperature acrophase (peak time) (p>0.05). Diurnal variation was found for performance tests, including sit-and-reach flexibility (p<0.01) and spinal hyper-extension (p<0.05). Peaks occurred between 16:00 and 20:00 h and the daytime changes paralleled the temperature rhythm. Diurnal variation was also found for football-specific tests, including dribbling time (p<0.001, peak at 20:00 h) and chip test performance (p<0.01), being more accurate at 16:00 h (mean error=0.75 m) than at 08:00 h (mean error=1.01 m). Results indicate football players perform at an optimum between 16:00 and 20:00 h when not only football-specific skills but also measures of physical performance are at their peak. Body temperature peaked at a similar time, but positive mood states seemed to peak slightly earlier. While causal links cannot be established in these experiments, the results indicate that the diurnal variation of some aspects of football performance is affected by factor(s) other than body temperature alone. 相似文献
997.
This paper analyses the effect of microclimatic factors (internal soil temperature, surface temperature and surface relative
humidity) on surface activity of Messor barbarus harvester ants. We selected 44 colonies in an area of Mediterranean grassland
near Madrid (Central Spain), which were monitored for activity between March 1998 and September 1999. Results indicate that
microclimatic factors are good predictors of colony activation and intensity of activity. Colonies became active above certain
critical values of internal soil temperature and relative humidity. For active colonies, surface temperature was the main
regulatory factor for worker departure rate, which peaked at around 25–30°C. Worker speed was positively correlated with surface
temperature, although the relationship was weaker for large-sized workers. Microclimatic factors were not enough, however,
to predict task allocation outside the nest. The explanation for this aspect of ant behavior probably requires the inclusion
of biotic factors in the models. 相似文献
998.
Female Tabanus nigrovittatus were field collected and used in laboratory experimentation to explore physiological and behavioral factors that affect engorgement. Previous studies showed sulfakinins act as feeding satiety factors in insects. This study demonstrates that sulfakinins have differing effects on engorgement that is dependent on the feeding technique used in the laboratory. The satiety effect of sulfakinin on flies engorging using the blood-soaked Kimwipe® feeding technique is not in agreement with previous experiments using an alternate feeding technique with artificial membranes. This study is the first to demonstrate that the temperature of blood is a significant factor for engorgement in this species. Also, the percentage of flies engorging is significantly different depending on the feeding technique used. 相似文献
999.
夏眠是刺参最重要的生理特征;水温升高是其夏眠的主要诱发因子,而夏眠的临界温度与刺参体重密切相关。为揭示刺参夏眠对其能量利用对策的影响,测定了2种体重规格(134.0±13.5)g和(73.6±2.2)g刺参在10、15、20、25℃和30℃5个温度梯度下的能量收支。结果表明,温度和体重及其交互作用对刺参能量的摄入均有显著影响;而温度是影响其摄食能分配的主要因素。研究发现,刺参在非夏眠期、夏眠临界期和完全夏眠期的能量利用对策有所不同:在非夏眠期,刺参摄食能支出的最大组分是粪便能,占摄食能的比例超过50%,其次为呼吸耗能,占19.8%~39.4%,而生长能和排泄能占的比例较小,分别为5.7%~10.7%和2.9%~3.7%;在夏眠临界温度下,呼吸和排泄耗能占摄食能的比例均显著增大(分别为88.3%和13.6%),而生长能所占比例降为负值(-55.3%),刺参表现为负生长;而在夏眠期,刺参的摄食能和排粪能为零,为维持其基本生理活动,不得不动用以往贮存于体内的能量,消耗于呼吸和排泄等生理过程,供维持生命之用。总之,从能量生物学的角度看,夏眠的主要生态学意义在于刺参长时间处于相对高温环境,进而导致摄食受阻条件下的一种能量节约方式。 相似文献
1000.
West Coast prairies in the US are an endangered ecosystem, and effective conservation will require an understanding of how
changing climate will impact nutrient cycling and availability. We examined how seasonal patterns and micro-heterogeneity
in edaphic conditions (% moisture, total organic carbon, % clay, pH, and inorganic nitrogen and phosphorus) control carbon,
nitrogen, and phosphorus cycling in an upland prairie in western Oregon, USA. Across the prairie, we collected soils seasonally
and measured microbial respiration, net nitrogen mineralization, net nitrification, and phosphorus availability under field
conditions and under experimentally varied temperature and moisture treatments. The response variables differed in the degree
of temperature and moisture limitation within seasons and how these factors varied across sampling sites. In general, we found
that microbial respiration was limited by low soil moisture year-round and by low temperatures in the winter. Net nitrogen
mineralization and net nitrification were never limited by temperature, but both were limited by excessive soil moisture in
winter, and net nitrification was also inhibited by low soil moisture in the summer. Factors that enhanced microbial respiration
tended to decrease soil phosphorus availability. Edaphic factors explained 76% of the seasonal and spatial variation in microbial
respiration, 35% of the variation in phosphorus availability, and 29% of the variation in net nitrification. Much of the variation
in net nitrogen mineralization remained unexplained (R
2 = 0.19). This study, for the first time, demonstrates the complex seasonal controls over nutrient cycling in a Pacific Northwest
prairie. 相似文献