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排序方式: 共有487条查询结果,搜索用时 15 毫秒
91.
Katarina?R.?NeufeldEmail author Sue?J.?Grayston Shabtai?Bittman Maja?Krzic Derek?E.?Hunt Sean?M.?Smukler 《Biology and Fertility of Soils》2017,53(6):613-626
Removing solids from liquid dairy manure slurry reduces manure phosphorus (P) and increases the available (mineral) fraction of nitrogen (N) but also decreases the organic matter content of the manure. While this novel treatment reduces environmental concerns associated with excess N and P application to soils, it may also reduce microbial biomass and activity in soil. This study evaluated the long-term effects of this alternative manure treatment compared to more typical nutrient applications in a perennial grass sward (tall fescue, Festuca arundinacea Schreb.) on soil microbial biomass, community composition, hydrolytic enzyme activity, and forage yield. Nutrient treatments for this long-term field experiment in Agassiz, British Columbia, Canada were started in 2003. The treatments included liquid dairy manure slurry, liquid dairy manure with solids removed, commercial fertilizer, a combination of fertilizer and dairy manure, and a control. All treatments were applied at 400–600 kg total N ha?1 year?1 in four equal doses. Soil microbial community composition (phospholipid fatty acid analysis) and activity (hydrolytic enzyme activity) were determined several times during the 2013 and 2014 growing seasons to a depth of 15 cm. Time of sampling (date) had a strong influence on microbial biomass, community composition, and activity, while the response to soil properties and yield was more varied. All manure treatments (dairy manure slurry, liquid fraction, and the combination) increased microbial biomass (by 19–32%) and the potential activity of cellulose-degrading enzymes (by 31–47%) compared to commercial fertilizer and unamended plots. The commercial fertilizer and liquid fraction lowered fungal/bacterial ratios compared with both whole manure and unamended plots. Our results indicate that separating the solid from the liquid fraction of manure, to improve crop yield and reduce P loading, did not reduce microbial community size and activity and that all manure treatments increased microbial biomass and activity compared to mineral fertilizer application. 相似文献
92.
Cotton RG Auerbach AD Axton M Barash CI Berkovic SF Brookes AJ Burn J Cutting G den Dunnen JT Flicek P Freimer N Greenblatt MS Howard HJ Katz M Macrae FA Maglott D Möslein G Povey S Ramesar RS Richards CS Seminara D Smith TD Sobrido MJ Solbakk JH Tanzi RE Tavtigian SV Taylor GR Utsunomiya J Watson M 《Science (New York, N.Y.)》2008,322(5903):861-862
An ambitious plan to collect, curate, and make accessible information on genetic variations affecting human health is beginning to be realized. 相似文献
93.
Dietary protein level and ruminal degradability for mohair production in Angora goats. 总被引:1,自引:0,他引:1
Twenty-eight Angora goat doelings (average BW 22.1 kg) were used in a 150-d study to examine the effects of dietary CP level and degradability on mohair fiber production. A 2 x 2 factorial arrangement was instituted using conventional, solvent-extracted soybean meal (high degradability) or expelled, heat-treated soybean meal (low degradability) incorporated into low- (12%) or high- (19%) CP diets. Grease and clean mohair weights were greater (P less than .05) in goats fed the diets containing 19% CP. Mohair fiber diameter was not affected (P greater than .10) by dietary CP level. Clean mohair weight tended (P less than .08) to be higher in the goats fed diets containing expelled, heat-treated soybean meal. Body weight gains were not affected (P greater than .10) by CP level or degradability, whereas DMI increased (P less than .01) with increasing CP level. Ruminal fluid pH and total VFA concentrations were not affected (P greater than .10) by diet. Ruminal ammonia N concentration increased (P less than .05) as CP level in the diet increased, and postprandial changes in concentrations were less noticeable in the group fed expelled, heat-treated soybean meal. Plasma urea N (P less than .001) and total protein (P less than .01) concentration increased as dietary CP level increased. Plasma glucose was elevated (P less than .001) 2 h after feeding in the goats fed conventional, solvent-extracted soybean meal, whereas glucagon concentrations were greater at 0 and 4 h in the group fed expelled, heat-treated soybean meal.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
94.
95.
Volatile organic compound (VOC) emissions from Sitka spruce (Picea sitchensis Bong.) growing in a range of controlled light and temperature regimes were monitored online with a proton transfer reaction-mass spectrometer (PTR-MS) operating at a temporal resolution of approximately 1 min. Isoprene emissions accounted for an average of more than 70% of measured VOCs and up to 3.5% of assimilated carbon. Emission rates (E) for isoprene correlated closely with photosynthetic photon flux (PPF) and temperature, showing saturation at a PPF of between 300 and 400 micromol m(-2) s(-1) and a maximum between 35 and 38 degrees C. Under standard conditions of 30 degrees C and 1000 micromol m(-2) s(-1) PPF, the mean isoprene E was 13 microg gdm(-1) h(-1), considerably higher than previously observed in this species. Mean E for acetaldehyde, methanol and monoterpenes at 30 degrees C were 0.37, 0.78 and 2.97 microg gdm(-1) h(-1), respectively. In response to a sudden light to dark transition, isoprene E decreased exponentially by > 98% over about 3 h; however, during the first 7 min, this otherwise steady decay was temporarily but immediately depressed to approximately 40% of the pre-darkness rate, before rallying during the following 7 min to rejoin the general downward trajectory of the exponential decay. The sudden sharp fall in isoprene E was mirrored by a burst in acetaldehyde E. The acetaldehyde E maximum coincided with the isoprene E minimum (7 min post-illumination), and ceased when isoprene emissions resumed their exponential decay. The causes of, and linkages between, these phenomena were investigated. 相似文献
96.
Sue Aenishaenslin Kate Convery Basil Gua Mia Spain Lee Tunstall 《Small-Scale Forestry》2007,6(2):141-155
Private native forests in Australia perform a dual production and conservation role, providing an important source of timber,
and complementing formal conservation reserves. A comparison of policies for private native forests in New South Wales, Queensland,
Victoria and Tasmania illustrates the scope for timber harvesting, the provision for environmental values, and initiatives
for responsible and sustainable forest management. The sustainable management of Australia’s forests requires initiatives
by both government and landowners to accommodate changes in community attitudes, new management strategies, integrated catchment
management principles and both commercial and non-commercial opportunities for forest use. Of all of the Australian states,
New South Wales has the most restrictive laws in terms of forest management and harvesting. Queensland and Victorian legislation
have a more commercial focus, while Tasmania has a balance of both environmental and commercial objectives. The duty of care
for private native forests is a responsibility that falls to the landholder, and while this should be enforced by legislation,
the private provision of community benefits requires both recognition and reward. The presence or absence of incentives potentially
determines the effectiveness of forest codes of practice. 相似文献
97.
98.
Mellor PJ Haugland S Murphy S Smith KC Holloway A Archer J Powell RM Polton GA Tasker S McCormick D Tempest ME McNeil PE Scase TJ Knott CD Bonfanti U Villiers EJ Argyle DJ Herrtage ME Day MJ 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(6):1376-1383
BACKGROUND: Myeloma-related disorders (MRD) are rare neoplasms of plasma cells. Published case reports describe a diversity of clinical presentations with confusing terminology and diagnostic criteria as a consequence of the assumption that MRD in cats are analogous to those in dogs or humans. OBJECTIVE: The aim of the study was to describe clinical, clinicopathologic and imaging findings, response to treatment, survival and possible associations with other diseases or vaccination in a large case series. A priori hypotheses were that cats with MRD commonly present with extramedullary involvement and uncommonly have radiographic bone lesions, in contrast to human patients. ANIMALS: Twenty-four cats with MRD confirmed by cytology or histopathology and immunohistochemistry. METHOD: A multicenter retrospective study was performed. RESULTS: Two types of clinical presentation were observed. The first group (n = 17) had neoplasia involving abdominal organs, bone marrow, or both. All developed systemic clinical signs and paraproteinemia. Five of 7 cats that received chemotherapy improved clinically or had decreased serum globulin concentration (median survival, 12.3 months; range, 8.5-22 months). The second group comprised 7 cats with skin masses, 2 of which were paraproteinemic and developed rapidly worsening systemic signs. In cats without systemic signs, excision of the skin masses appeared to be associated with prolonged survival (up to 2.4 years). Cats with MRD commonly presented with extramedullary involvement (67%), versus humans with MRD (5%) (P < .001), and uncommonly presented with radiographic bone lesions (8%) versus humans with MRD (80%) (P < .001). CONCLUSIONS: Radiographic bone lesions are uncommon in cats with MRD and extramedullary presentation is common, relative to human myeloma. 相似文献
99.
Booth S 《Public health nutrition》2006,9(2):212-218
OBJECTIVE: The aim of this study was to determine the food sources and acquisition practices used by homeless youth in Adelaide. This work is part of a larger study that aimed to examine the extent and nature of food insecurity among homeless youth. DESIGN: Cross-sectional design involving quantitative and qualitative methods. SETTING: Four health and welfare inner-city agencies serving homeless youth in Adelaide, South Australia. SUBJECTS: A sample of 150 homeless youth aged between 15 and 24 years recruited from these agencies. Fifteen were selected via snowball sampling for interview. RESULTS: Use of welfare food sources was high (63%). Food from welfare agencies was supplemented by unorthodox food acquisition methods such as theft (65%), begging for money for food (61%), begging for food items (44%) and asking for help from friends and relatives (34%). Reasons given for non-usage of welfare food services included affordability, access, being too busy, shame or embarrassment. CONCLUSIONS: Food insecurity is a salient issue for some homeless youth in Adelaide. Clarifying food acquisition practices of food-insecure homeless youth is essential for rational planning and improvement of food-related services to meet their needs. Such an understanding also underpins the development of broader public policy responses that improve individual and household skills and resources to acquire food and ensure food security. Nutrition professionals, welfare professionals and policy-makers need to work sensitively with welfare food agencies and others to improve food access and food security for homeless youth. 相似文献
100.
Rhee SG 《Science (New York, N.Y.)》2006,312(5782):1882-1883