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排序方式: 共有211条查询结果,搜索用时 31 毫秒
41.
Suarez Luz Angelica Robson Andrew McPhee John O’Halloran Julie van Sprang Celia 《Precision Agriculture》2020,21(6):1304-1326
Precision Agriculture - Proximal and remote sensors have proved their effectiveness for the estimation of several biophysical and biochemical variables, including yield, in many different crops.... 相似文献
42.
Lopez-Rodriguez Norma A. Gaytán-Martínez Marcela de la Luz Reyes-Vega María Loarca-Piña Guadalupe 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(4):447-457
Plant Foods for Human Nutrition - Alternative therapies, such as phytotherapy, are considered to improve the health status of people with chronic non-communicable diseases (CNCDs). In this regard,... 相似文献
43.
Welliene M. Santos Leandro S. Costa Jose F. Lpez‐Olmeda Natlia Cristina S. Costa Fabio A. C. Santos Pedro G. Gamarano Walisson S. Silva Priscila V. Rosa Ronald K. Luz Paula A. P. Ribeiro 《Aquaculture Research》2020,51(7):2973-2984
While some studies have investigated the effects of dietary protein on the activities of protease in Nile tilapia, little information exists about these enzymes and hormones regulating appetite at the molecular level. Therefore, we investigated the performance, protease activities and expression of genes related to protein intake and digestion in juvenile tilapia fed with diets containing different levels of crude protein (CP): 25.14, 31.12, 36.60 and 42.05%. The fish were fed to apparent satiation three times a day for 65 days. The animal performance and the retention rates of protein and energy linearly decreased with an increase in dietary CP content. A positive quadratic effect of CP on pepsinogen was observed, although the acid protease activity was not affected. Trypsinogen and trypsin activity in the intestine presented similar patterns, showing a positive quadratic response to dietary protein levels. A linear increase in intestinal chymotrypsinogen expression was observed, but the activity of chymotrypsin showed a positive quadratic response. In addition, the expression of cholecystokinin (cck) and peptide yy (pyy) increased linearly with increasing CP. Dietary protein modulates the activity of alkaline proteases as well as the expression of these protease genes and hormones involved in appetite regulation. These changes can help expand our understanding of feed intake and digestion control, thereby improving feed formulations for this species. 相似文献
44.
A study was made of the growth and survival of postlarvae and spat of Argopecten nucleus and Nodipecten nodosus produced in the laboratory and exposed to different conditions of settlement and culture. An evaluation was made of the different types of collection substrates (onion-bags, artificial-grass, fibreglass-plates), two types of settlement inducers (epinephrine, low temperature), and two culture environments (sea, laboratory). The results showed that larger numbers of postlarvae were obtained in artificial-grass collectors than on fibreglass-plates or in the onion-bags. The growth of the A. nucleus postlarvae was not affected by the collector type, while that of N. nodosus was higher on fibreglass-plates, and lesser in the onion-bags. Both thermal and chemical stimulation of the competent larvae resulted in recovery of a greater percentage of postlarvae. The growth of postlarvae of A. nucleus was better in groups exposed to the two methods of settlement induction, while those of N. nodosus remained unaffected by this treatment. The survival of the postlarvae and spat was greater in the laboratory than at sea except in the case of A. nucleus postlarvae attached to collectors, whose survival was similar in both environments. The growth of postlarvae and spat was greater in the sea than in the laboratory. 相似文献
45.
Several experiments were performed examining the effect of different culture variables on the growth and survival of Argopecten nucleus and Nodipecten nodosus larvae. Higher growth and survival values were obtained at a low density (1 larvae mL?1) than at a high density (5 larvae mL?1), except for N. nodosus's survival, which was not affected by density. Higher growth was obtained when feeding the larvae a diet of Isochrysis galbana, similar results occurred with the diet of Isochrysis galbana+Chaetoceros calcitrans in A. nucleus and with I. galbana combined with the lipid emulsion EmDHA in N. nodosus. Higher survival was obtained when the diet included a mixture of microalgae than when EmDHA was supplemented. Growth and survival of the larvae of A. nucleus were greater when fed continuously, while N. nodosus grew and survived better when food was given discontinuously. Higher growth and survival values were recorded at lower food concentrations ranging from 20 to 40 cells μL?1 of I. galbana. Higher growth was observed with increasing temperature between 22 and 28 °C, although there was a simultaneous decrease in survival. No significant effects on larval production parameters were found when the culture water was changed totally or partially, but higher larval growth of N. nodosus was verified when a partial renewal of water was performed. 相似文献
46.
47.
Marsicano G Goodenough S Monory K Hermann H Eder M Cannich A Azad SC Cascio MG Gutiérrez SO van der Stelt M López-Rodriguez ML Casanova E Schütz G Zieglgänsberger W Di Marzo V Behl C Lutz B 《Science (New York, N.Y.)》2003,302(5642):84-88
Abnormally high spiking activity can damage neurons. Signaling systems to protect neurons from the consequences of abnormal discharge activity have been postulated. We generated conditional mutant mice that lack expression of the cannabinoid receptor type 1 in principal forebrain neurons but not in adjacent inhibitory interneurons. In mutant mice,the excitotoxin kainic acid (KA) induced excessive seizures in vivo. The threshold to KA-induced neuronal excitation in vitro was severely reduced in hippocampal pyramidal neurons of mutants. KA administration rapidly raised hippocampal levels of anandamide and induced protective mechanisms in wild-type principal hippocampal neurons. These protective mechanisms could not be triggered in mutant mice. The endogenous cannabinoid system thus provides on-demand protection against acute excitotoxicity in central nervous system neurons. 相似文献
48.
Isela Lavilla A. V. Filgueiras F. Valverde J. Millos A. Palanca C. Bendicho 《Water, air, and soil pollution》2006,172(1-4):273-293
Depth concentration profiles of 26 elements, i.e. trace elements (As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, Rb, Sr, V and Zn), lithophiles (Si, Al, Fe, Mn, Na, K, Mg, Ca and Ti) and nutrients (C, P, N, S) have been established in a sediment core collected at the Respomuso Lake (Pyrenees, Spain). This high altitude lake of glacier origin was transformed into reservoir in the fifties of last century. Correlations among the depth profiles of the above elements were established. HCl-extractable elements, which are better related to bioavailability, followed the profiles of total contents. Principal component analysis was applied to establish the binding behaviour of trace elements in the sediment matrix and, in turn, to search for their anthropogenic or natural sources. It was seen that Cu, Ni, Pb, Sr and Zn clustered together, and with exception of Sr, they were not clearly associated with any major component of the sediment. Their depth profiles correlate well with each other, hence indicating their presence as a result of atmospheric pollution. Redox-sensitive elements such as Fe and Mn follow a similar trend along the vertical profile. Depth profiles of As an Co correlate well with those of Fe and Mn. Principal component analysis showed that As, Co, Fe and Mn clustered together, which confirms the close association of As and Co with Fe-Mn oxyhydroxides. As concentrations in many strata exceed the ERM value, and therefore, significant biological effects are expected. Dissolution of minerals such as pyrite, chalcopyrite and galena taking part in the mineralogy of this area accounts for the As concentration found. Ba, Cr, Rb and V were associated with the sediment matrix (aluminosilicates), hence showing low mobility. 相似文献
49.
Maria Luz George Ellen Regalado Marilyn Warburton Surinder Vasal David Hoisington 《Euphytica》2004,135(2):145-155
A major emphasis in maize breeding in Asian countries has been the improvement for resistance to downy mildew, a serious disease
that causes significant yield losses. A total of 102 inbred lines, including lines from Asian breeding programs, Mexico, USA
and Germany, were analyzed with 76 SSR markers to measure diversity and investigate the effect of selection for downy mildew
resistance. A mean polymorphism information content of 0.59, with a range of 0.14 to 0.83, was observed. Diversity at the
gene level showed an average of 5.4 alleles per locus and a range of two to 16 alleles per locus, with a total of 409 alleles.
About half of the alleles in the Asian lines had frequencies of 0.10 or less, and only 2% had frequencies > 0.80, indicating
the presence of many alleles, and thus a high level of diversity. Some of the high-frequency alleles were in chromosomal regions
associated with disease resistance. However, the frequencies of alleles in three SSR loci that are linked to a QTL for resistance
to downy mildews in Asia were not significantly different in the subtropical/tropical Asian lines as compared to all the lines
in the study. Lines from the US, Germany, and China, comprised three clusters of temperate maize(GS = 0.31), while those from
India, Indonesia, Philippines, Thailand, Vietnam and CIMMYT comprised seven indistinct clusters of subtropical and subtropical
maize (GS = 0.29). We conclude that maize breeding activity in Asia has not caused a decline in the overall amount of diversity
in the region.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
50.
Kuzumitsu Matsumoto Milena Luz Barbosa Luiz Augusto Copati Souza João Batista Teixeira 《Euphytica》1995,84(1):67-71
Summary The selection of tolerant variants to race 1 fusarium wilt of banana was carried out through the effects of fusaric acid onin vitro banana multiple bud clumps (MBCs). The MBCs of Maçã cultivar (Musa sp., AAB, Silk), which is susceptible to the race 1 fusarium wilt, were used. And, Nanicão cultivar (AAA, Cavendish subgroup) was used in the tolerant tests as control of a disease tolerant variety. Firstly, to aim at determining an appropriate concentration of the toxin for the tolerant selection, the MBCs were cultured on the Modified Murashige & Skoog medium supplemented with 0.05 to 1.6 mM fusaric acid. The growth on both cultivars was completely inhibited on the medium containing 0.1 mM fusaric acid.Tolerant variants of Maçã were, then, selected with 0.1 mM fusaric acid after chemical mutagen treatment. The results showed an increased tolerance of the selected Maçã plants to the race 1 fungus in greenhouse tests.
In vitro selection by fusaric acid is a very useful method for obtaining fusarium disease tolerance, although the tolerance mechanism of the selected plants may be different from that of existing tolerant cultivars. 相似文献