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71.
The Public Trust Doctrine (PTD) vests states with a fiduciary responsibility to manage wildlife for the benefit of current and future generations. States have varied approaches to applying the PTD for wildlife management ranging from a traditional focus on hunters, anglers, and trappers to a progressive approach of broad inclusion of all potential stakeholders in their decision-making processes. We argue that states need to gather and incorporate more and better human dimensions (HD) information to fulfill their PTD responsibilities. We describe some of the barriers to increased use of HD and the changes in agency culture, staffing, data gathering, and decision-making processes necessary to integrate HD effectively and comport with the PTD. We conclude that in addition to increasing fulfillment of PTD responsibilities, increased use of HD information will help maintain agency relevance, increase political support, and secure broader agency funding. 相似文献
72.
The cultivation of fast growing trees on agricultural sites is an area undergoing a growth in interest due to the rising demand for woody biomass as a source of bioenergy. Short rotation alley cropping systems (SRACS) represent a promising possibility to combine annual crops for food, fodder or bioenergy with woody plants for biomass production, doing so through an integration of hedgerows of fast growing trees into conventional agricultural sites. Against such developments, the question has arisen as to what extent hedgerows in SRACS can act as an effective windbreak despite their management-related low height of only a few meters. On the basis of multiannual recorded wind velocity data in high resolution at two sites in Germany, it could be shown that the wind speed on crop alleys was reduced significantly by such hedgerows. At the central point of 24 m wide crop alleys, the wind speed decreased on an annual average basis by more than 50 % when compared to the wind speeds of open field. The overall amount of reduction was strongly dependent on the location within the crop alleys, the height of trees, the distance between two hedgerows, and their orientation. In reflection upon these results, it was concluded that the establishment of SRACS could lead to enhanced soil protection against wind erosion and thus to ecological and economic benefits for agricultural sites. 相似文献
73.
Mahbubul Alam Alain Olivier Alain Paquette Jérôme Dupras Jean-Pierre Revéret Christian Messier 《Agroforestry Systems》2014,88(4):679-691
This study provides the first complete framework for the valuation of ecosystem services of agroforestry and uses a tree-based intercropping (TBI) system in southern Québec, Canada, as a case study. Ten ecosystem services were estimated, all of which were of interest and directly applicable to most agricultural systems worldwide: nutrient mineralization, water quality, soil quality, pollination, biological control, air quality, windbreak, timber provisioning, agriculture provisioning, and climate regulation. A mix of mathematical models for the quantification and economic valuation of various ecosystem services were used. The results revealed a total annual margin of $2,645 ha?1 y?1 (averaged over 40 years). The economic value of combined non-market services was $1,634 ha?1 y?1, which was higher than the value of marketable products (i.e. timber and agricultural products). An analysis of the present value suggested that agricultural products ranked highest among the ecosystem services taken singularly, followed by water quality, air quality, climate regulation, and soil quality maintenance. Total economic value of all ecosystem services for the rotation period was $54,782 ha?1, only one third of which was contributed by agricultural products. Although the total value of the ecosystem services provided by TBI was high, farmers only benefited from agricultural and timber products. Thus, government incentives are needed to interest farmers in adopting practices that benefit society as a whole. 相似文献
74.
Katja Albert Peter Annighöfer Jens Schumacher Christian Ammer 《Scandinavian Journal of Forest Research》2014,29(3):210-221
With an increasing demand of sustainable raw materials for bioenergy use, coppicing as management approach to increase the biomass production of forests is becoming of greater importance. This study describes the parameterization of biomass equations for six tree species traditionally used in coppices forests, namely sycamore maple (Acer pseudoplatanus L.), field maple (Acer campestre L.), European ash (Fraxinus excelsior L.), European hornbeam (Carpinus betulus L.), downy birch (Betula pubescens Ehrh.), and common hazel (Corylus avellana L.) growing in coppice-with-standard systems in Lower Saxony, Germany. The parameterization was based on measurements of over 950 trees sampled from two forest sites. The sampled trees were felled and separated into three biomass compartments (stem, coarse branches, and fine brushwood) and weighed on site. The dry weight of sub samples from each compartment was measured. Equations were derived for total aboveground biomass, stem biomass, and crown biomass using regression analyses. We either used diameter at breast height as single independent explanatory variable or in combination with tree height. Biomass production of stump sprouts and generatively grown stems was compared for ash and sycamore maple. In the same age classes, it was found that ash stump sprouts had a slightly higher production than seed-grown stems. For sycamore maple, no difference was detected. 相似文献
75.
Tyrosine hydroxylase activity and dopamine turnover of rainbow trout (Oncorhynchus mykiss) brain: the special status of the hypothalamus 总被引:1,自引:0,他引:1
Boris Linard Sanae Bennani Patrick Jego Christian Saligaut 《Fish physiology and biochemistry》1996,15(1):41-48
The dynamics of catecholamine (CA)-synthesis enzymes have been poorly studied in fish. Tyrosine hydroxylase (TH), the rate-limiting enzyme of CA synthesis has been only studied inin vitro conditions. In the present report thein vivo CA synthesis and the CA metabolism were studied in different regions of the forebrain of the rainbow trout. Levels of norepinephrine (NE), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and the rate of accumulation of 3,4-dihydroxyphenylalanine (DOPA) were determined by HPLC following a treatment with hydroxybenzylhydrazine (NSD), a potential inhibitor of DOPA decarboxylase. Kinetics of the accumulation of DOPA and of the decline of DOPAC were in agreement with those found in rat, evidencing that the accumulation of DOPA following NSD can be used in trout to quantify thein vivo enzymatic activity of tyrosine hydroxylase. Experiments using treatment with NSD or with methyl-p-tyrosine reached a same conclusion: the DA neuronal activity in trout is much higher than NE neuronal activity. However, the hypothalamus had high DA levelsvs. lowin vitro andin vivo TH activities and exhibited a low CA turnover. 相似文献
76.
Rhizoctonia solani is a complex species that is composed of different anastomosis groups (AG). Although these different AGs show differences in their host ranges, generally R. solani is a phytopathogenic species with a wide spectrum of hosts. It has the ability to grow as a saprotroph, which further complicates its behaviour as a parasite. The losses caused by R. solani are very important and need a sustainable management strategy. The patchy appearance of the disease caused by this pathogen is well-known. The patches show within and between season dynamics. The factors which affect the spread of the disease can be grouped into three main categories: host plant, pathogen and environment. However, each of the categories in its detail may depend on or react with the other categories. There are a number of factors that may be involved in dynamics of patches. These potential mechanisms are discussed. It is essential to know about the mechanisms involved to develop an effective control strategy. Although more work is needed to investigate different mechanisms of parasitism deployed by different AGs in different hosts, it seems that many mechanisms external to the host are operating at the same time which necessitates an integrative research approach to study and control the diseases caused by R. solani. 相似文献
77.
Fenaille F Visani P Fumeaux R Milo C Guy PA 《Journal of agricultural and food chemistry》2003,51(9):2790-2796
Two headspace techniques based on mass spectrometry detection (MS), electronic nose, and solid phase microextraction coupled to gas chromatography-mass spectrometry (SPME-GC/MS) were evaluated for their ability to differentiate various infant formula powders based on changes of their volatiles upon storage. The electronic nose gave unresolved MS fingerprints of the samples gas phases that were further submitted to principal component analysis (PCA). Such direct MS recording combined to multivariate treatment enabled a rapid differentiation of the infant formulas over a 4 week storage test. Although MS-based electronic nose advantages are its easy-to-use aspect and its meaningful data interpretation obtained with a high throughput (100 samples per 24 h), its greatest disadvantage is that the present compounds could not be identified and quantified. For these reasons, a SPME-GC/MS measurement was also investigated. This technique allowed the identification of saturated aldehydes as the main volatiles present in the headspace of infant milk powders. An isotope dilution assay was further developed to quantitate hexanal as a potential indicator of infant milk powder oxidation. Thus, hexanal content was found to vary from roughly 500 and 3500 microg/kg for relatively non-oxidized and oxidized infant formulas, respectively. 相似文献
78.
Spyra Marcin Kleemann Janina Cetin Nuket Ipek Vázquez Navarrete Cesar Jesús Albert Christian Palacios-Agundez Igone Ametzaga-Arregi Ibone La Rosa Daniele Rozas-Vásquez Daniel Adem Esmail Blal Picchi Paolo Geneletti Davide König Hannes J. Koo HongMi Kopperoinen Leena Fürst Christine 《Landscape Ecology》2019,34(7):1715-1735
Landscape Ecology - Several case studies investigated the role of ecosystem services in participatory planning processes. However, no systematic study exists that cuts across a large number of... 相似文献
79.
Electromyographic activity of the longissimus dorsi muscles in horses during trotting on a treadmill
OBJECTIVE: To use electromyography (EMG) to measure physiologic activity of the longissimus dorsi muscles of horses during trotting on a treadmill. ANIMALS: 15 adult horses (5 to 20 years old that weighed 450 to 700 kg) that did not have clinical signs of back pain. PROCEDURE: Data were recorded for each horse during trotting on a treadmill at speeds of 2.6 to 4.4 m/s. Surface electromyography was recorded bilaterally from the longissimus dorsi muscles at the levels of T12, T16, and L3. RESULTS: In each motion cycle, 2 EMG maxima were found at the end of the diagonal stance phases. The EMG activity peaked slightly later at L3 than at T12 and T16. Maximum EMG amplitudes were highest at T12 and decreased caudally, with mean +/- SD values of 4.51 +/- 1.20 mV at T12, 3.00 +/- 0.83 mV at T16, and 1.78 +/- 0.67 mV at L3. Mean minimum EMG activity was 1.30 +/- 0.63 mV at T12, 0.83 +/- 0.35 mV at T16, and 0.80 +/- 0.39 mV at L3. The relative amplitudes (ie, [maximum - minimum]/maximum) were 67 +/- 11% at T12, 66 +/- 8% at T16, and 71 +/- 8% at L3. CONCLUSIONS AND CLINICAL RELEVANCE: Activity of the longissimus dorsi muscles is mainly responsible for stabilization of the vertebral column against dynamic forces. The difference between minimum and maximum activity may allow application of this method as a clinical tool. Data reported here can serve as reference values for comparison with values from clinically affected horses. 相似文献
80.
Ingrid M. Malebane Jones Wilfred Ng’ambi David Norris Christian Mbajiorgu 《Tropical animal health and production》2010,42(8):1711-1718
Two experiments were carried out to determine the effect of dietary ascorbic acid supplementation levels on productivity,
carcass characteristics, and mortality of indigenous Venda chickens. The first experiment determined the effect of dietary
ascorbic acid supplementation levels on productivity and mortality rate of 175 unsexed Venda chickens between 1 and 6 weeks
old. The second experiment determined the effect of dietary ascorbic acid supplementation levels on productivity, carcass
characteristics, and mortality rate of 140 female Venda chickens between 8 and 13 weeks old. A completely randomized design
was used in both experiments. Supplementation of grower diets with ascorbic acid ranged from 0 to 2,000 mg per kg DM feed
in both experiments. Levels of ascorbic acid supplementation for optimum feed intake, feed conversion ratio, growth rate,
live weight, and breast meat yield were determined using a quadratic equation. The optimal dietary ascorbic acid supplementation
levels for feed conversion ratio, growth rate, and live weight of Venda chickens during the starter phase were 1,050, 1,301,
and 1,500 mg/kg DM feed, while, at the grower phase, the optimal supplementation levels for feed conversion ratio, growth
rate, live weight, and breast meat yield were 1,000, 1,250, 1,482, and 769 mg/kg DM feed, respectively. Results indicate that
different levels of ascorbic acid supplementation optimized feed conversion ratio, growth rate, and live weight of Venda chickens
at each growth phase. However, levels of ascorbic acid supplementation for optimum feed conversion ratio, growth rate, and
live weight were higher than that for breast meat yield. These findings have implications on ration formulation for Venda
chickens. 相似文献