全文获取类型
收费全文 | 212篇 |
免费 | 12篇 |
专业分类
林业 | 31篇 |
农学 | 10篇 |
基础科学 | 1篇 |
50篇 | |
综合类 | 15篇 |
农作物 | 11篇 |
水产渔业 | 22篇 |
畜牧兽医 | 48篇 |
园艺 | 9篇 |
植物保护 | 27篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 9篇 |
2020年 | 13篇 |
2019年 | 19篇 |
2018年 | 16篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 20篇 |
2013年 | 12篇 |
2012年 | 20篇 |
2011年 | 17篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有224条查询结果,搜索用时 46 毫秒
151.
Grzegorz Pasternak Piotr Rutkowski Ewa ?liwka Barbara Ko?wzan Justyna Rybak 《Water, air, and soil pollution》2011,214(1-4):599-608
Coal carbonization by-products contain up to 10,000 aliphatic and aromatic compounds. Many of them show toxic, mutagenic, and carcinogenic character. In this study, we examined 51 pure bacterial cultures of their ability of coal tar constituent biodegradation. Bacterial cultures were isolated from both explosives and coal tar-contaminated areas. Among all of the investigated strains, 19 showed biodegradative activity. One of the isolates degraded 40% of the substrate in 14 days at a temperature of 15°C. The most active strain was identified by both classic and 16S ribosomal DNA sequencing methods and designated Rhodococcus erythropolis B10. The biodegradation of coal tar constituents, performed by identified strain, was assessed by GC/MS technique. The comparison of samples analyzed by GC/MS before and after biodegradation indicated high degradative potential of the chosen strain. It was able to degrade n-paraffins, n-olefins, benzene, alkylbenzenes, cadalene, and other PAHs, as well as recalcitrant heterocyclic compounds dibenzofuran and its methyl-substituted derivative. The B10 strain isolated and tested in this research shows promising possibilities to be used in field conditions. The biodegradation experiments indicated that satisfactory results may be obtained even in pure bacterial cultures. 相似文献
152.
The parallel coordinate plot is proposed as an efficient tool for visualization of 13 traits of "stay-green" maize(Zea mays L.) cultivar exposed to different methods of magnesium application. The field experiment was conducted in the Department of Agronomy, Poznań University of Life Sciences, on the fields of the Department of Teaching and Experimental Station in Swadzim in 2006–2008. Experiment was conducted as a single-factor experiment with seven applications of magnesium in a randomized complete block design with four replicates. The highest mean values of grain yield and 1 000-grain weight were obtained after application of variant T3 of magnesium(10 kg MgO ha–1 soil) in the all three years of study. 相似文献
153.
Mazmanian SK Skaar EP Gaspar AH Humayun M Gornicki P Jelenska J Joachmiak A Missiakas DM Schneewind O 《Science (New York, N.Y.)》2003,299(5608):906-909
The cell wall envelope of Gram-positive pathogens functions as a scaffold for the attachment of virulence factors and as a sieve that prevents diffusion of molecules. Here the isd genes (iron-regulated surface determinant) of Staphylococcus aureus were found to encode factors responsible for hemoglobin binding and passage of heme-iron to the cytoplasm, where it acts as an essential nutrient. Heme-iron passage required two sortases that tether Isd proteins to unique locations within the cell wall. Thus, Isd appears to act as an import apparatus that uses cell wall-anchored proteins to relay heme-iron across the bacterial envelope. 相似文献
154.
Agnieszka Noszczyk-Nowak Józef Nicpoń Marcin Nowak Piotr Slawuta 《Acta veterinaria Scandinavica》2009,51(1):6
The study aimed at defining reference values for electrocardiographic (ECG) and echocardiographic parameters as well as macroscopic dimensions of the heart and microscopic dimensions of cardiomyocytes in the European brown hare. The studies were conducted on 30 adult, clinically healthy hares of either sex caught in Poland. ECG and echocardiography were performed supravitally on anaesthetized hares. After euthanasia, gross and microscopic myocardial and cardiomyocyte dimensions were determined. Heart rate amounted to 140 ± 37.5 beats/min, the leading rhythm involved the sinus rhythm. P wave time was 26 ± 5 ms, PQ time was 80 ms, QRS time was 29 ± 3.5 ms, and ST was 97.5 ± 7 ms. Echocardiography determined a left ventricular wall end-diastolic diameter of 8.6 ± 2.0 mm and an intraventricular septum end-diastolic diameter of 5.75 ± 1.0 mm. The thickness of the interventricular septum corresponded to that of the free wall of the left ventricle, a finding consistent with physiological hypertrophy. Preliminary reference values were established for echocardiography. The findings were similar to those obtained at necropsy. The ECG and echocardiographic studies represent the first supravital examination of cardiac function in the hare. The obtained results illustrate adaptation of hare''s myocardium to its mode of life. The cardiac findings resemble the athlete''s heart syndrome described in humans. The findings may prove useful in further studies on the physiology of the cardio-vascular system in the hare. 相似文献
155.
ABSTRACTThe aim of the study was to assess the effects of different forest stands (Silver fir (Abies alba) and sycamore maple (Acer pseudoplatanus) with common hornbeam (Carpinus betulus)) on the enzymes activities and microbial biomass. The objective was to explore how changes in the detritus inputs affect soil organic matter (SOM) composition. The content of SOM fraction has been compared with soil enzyme activities. The investigation was carried out in the ?wi?tokrzyskie Mountains of central Poland. Twenty investigation plots were selected, including fir stands (10 plots) and maple with hornbeam stands (10 plots). Contents of organic C, N and base cations, pH, hydrolytic acidity, and soil texture were investigated. The content of C and N in the physically separated SOM fractions was distinguished. The study indicated only small changes in soil properties and stabilization of organic matter as a result of different detritus inputs. The maple-hornbeam and fir stands have a similar influence on microbiological processes and the SOM. Acidity of soil is a major factor affecting microbial activity and therefore pH affects enzyme dynamics. Differences in soil pH confirmed the stronger acidifying effects of fir stands compared to maple-hornbeam stands. Additionally, fir stands stimulate β-glucosidase activity, probably through a simultaneous interaction of mycorrhizal fungi in the roots of fir stands. 相似文献
156.
Czubinski J Dwiecki K Siger A Kachlicki P Neunert G Lampart-Szczapa E Nogala-Kalucka M 《Journal of agricultural and food chemistry》2012,60(7):1830-1836
Lupin seed globulin proteins form complexes with flavonoids, predominantly apigenin C-glycosides. Enzymes typical for the gastrointestinal tract were used to hydrolyze lupin seed globulins. Release of native flavonoids as a result of the proteolysis reaction was observed. Different analytical methods such as size exclusion chromatography, HPLC-MS, and fluorescence spectroscopy (steady-state fluorescence, fluorescence anisotropy, fluorescence lifetimes) were used for a detailed characterization of this phenomenon. Flavonoids liberated from lupin globulin proteins as a result of pancreatin-catalyzed digestion were bound by γ-conglutin resistant to this enzyme. Two possible mechanisms of this interaction may be suggested: hydrogen bonding between oligosaccharide chains of glycoproteins and the sugar moieties of the flavonoid glycosides or electrostatic attraction between positively charged γ-conglutin and flavonoids partially ionized at pH 7.5. 相似文献
157.
158.
159.
Stanislav Koper Marek Mucha Piotr Silmanowicz Janusz Karpiski Tadeusz Zilo 《Veterinary radiology & ultrasound》1982,23(2):50-55
Difficulty in recognition of some diaphragmatic hernias in dogs have stimulated the authors to develop a diagnostic method consisting of selective angiography of the cranial mesenteric and celiac arteries. The basis for the experimen was that each herniated visceral organ is usually displaced with its vessels. The experiment was carried out on 14 mongrel dogs. Four dogs served as controls. Different kinds of diaphragmatic hernias were surgically created in 10 dogs. Survey abdominal radiographs, gastrointestinal tract contrast studies and selective abdominal angiography were performed 14 days later. In angiograms of dogs with omental diaphragmatic hernias, displacement of branches of the left gastroepiploic artery into the thorax was seen. In angiograms of dogs with hepatic diaphragmatic hernias, branches of the common hepatic artery were seen to enter the thorax. In dogs with herniated small intestine, the jejunal branches of the cranial mesenteric artery were seen entering the thorax. Potential possibilities of selective abdominal angiography for diagnosis of diaphragmatic hernias are discussed. 相似文献
160.
Piotr Duchnowicz Piotr Szczepaniak Maria Koter 《Pesticide biochemistry and physiology》2005,82(1):59-65
In the present work, we describe the effect of chlorophenoxyl herbicides 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid, and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and their metabolites (2,4-dichlorophenol, 4-chloro-2-methylphenol, 2,4-dimethylphenol, and 2,4,5-trichlorophenol) on the activity of ATPase and the corresponding protein damage (measured by loss of -SH group). Basic compounds caused an increase in the activity of the enzyme by 7-9% (at concentration 1 mM). For higher concentrations (2 and 4 mM), a decrease in the ATPase activity was observed for all investigated compounds. The increase of the free -SH group content was observed for all compounds. More profound changes in investigated parameter values were observed for metabolites (when compared to basic compounds) which may suggest their higher toxicity. 相似文献