全文获取类型
收费全文 | 521篇 |
免费 | 40篇 |
专业分类
林业 | 69篇 |
农学 | 18篇 |
基础科学 | 1篇 |
104篇 | |
综合类 | 22篇 |
农作物 | 43篇 |
水产渔业 | 33篇 |
畜牧兽医 | 196篇 |
园艺 | 21篇 |
植物保护 | 54篇 |
出版年
2023年 | 3篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 37篇 |
2017年 | 25篇 |
2016年 | 36篇 |
2015年 | 16篇 |
2014年 | 27篇 |
2013年 | 27篇 |
2012年 | 36篇 |
2011年 | 53篇 |
2010年 | 22篇 |
2009年 | 16篇 |
2008年 | 28篇 |
2007年 | 30篇 |
2006年 | 28篇 |
2005年 | 26篇 |
2004年 | 15篇 |
2003年 | 20篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 3篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1963年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1932年 | 1篇 |
1926年 | 2篇 |
1918年 | 2篇 |
排序方式: 共有561条查询结果,搜索用时 31 毫秒
541.
Milovanović V Radulović N Todorović Z Stanković M Stojanović G 《Plant foods for human nutrition (Dordrecht, Netherlands)》2007,62(3):113-119
The hydro-alcoholic extracts of five Equisetum species, E. arvense L., E. sylvaticum L., E. fluviatile L., E. palustre L. and E. telmateia Ehrh., growing-wild in Serbia were evaluated for their genotoxicity, antimicrobial activity, antioxidant capacity and the results
related to the total phenol content and HPLC flavonoid profiles. The total phenol content was 92–349 μmol expressed as equivalents
of chlorogenic acid per g of dried plant material. Main identified compounds were kaempferol-, quercetin- glycosides and caffeic
acid derivatives. E. telmateia extract showed the greatest antioxidant capacity. Almost all tested microorganisms demonstrated some degree of sensitivity
to the examined extracts. All tested extracts at 62.5 μg/ml showed higher incidence of micronucleus formation than in the
control sample. The obtained data allowed mutual comparison of examined species and their assessment as possible sources of
antioxidants, antimicrobials and/or genotoxic substances. 相似文献
542.
Belovari T Stević N Gajović S Kostović-Knezević L 《Anatomia, histologia, embryologia》2004,33(2):90-95
Different experimental systems are used to study developmental processes in mammals. In this study, three experimental models were analysed and correlated: (1) cultivation of rat embryos in vitro; (2) cultivation in vitro and then transplantation in vivo; (3) direct transplantation in vivo. When embryos were cultivated in vitro and then transplanted in vivo, after the initial in vitro restriction, developmental potential was recovered. The in vitro restriction depended on medium used and duration of culture. Pre-cultivation in serum-free medium for 7 days restricted developmental potential for nervous tissue, and for 14 days restricted developmental potential for skeletal muscles, adipose tissue and glandular epithelia. Transferrin addition improved in vitro differentiation of neuroblasts, cartilage and columnar epithelium. In the combined in vitro and in vivo method, transferrin preserved developmental potential in comparable extent to the addition of the serum. Even in serum-free conditions in vitro, the subsequent in vivo wide expression of developmental potential was possible. Therefore, the combination of in vitro and in vivo methods turned to be advantageous than the isolated approaches (in vitro or in vivo only), and enabled testing in more detail the influence of a single substance on developmental course and potential. 相似文献
543.
544.
Nicotiana wuttkei Clarkson and Symon discovered in the 1990s in Australia may be of potential interest to breeders as it carries resistance
to Peronospora hyoscyami de Bary. The crossability between N. wuttkei (2n = 4x = 32) and three N. tabacum (2n = 4x = 48) cultivars (‘Puławski 66’, ‘Wiślica’ and ‘TN 90’) and the morphology and cytology of their amphihaploid hybrids (2n = 4x = 40) were studied. Seeds were produced only when N. wuttkei was used as the maternal parent, but under normal germination all seedlings died. Viable F1 hybrids of N. wuttkei × N. tabacum cv. ‘Puławski’ and N. wuttkei × N. tabacum cv. ‘Wiślica’ were obtained only by in vitro cotyledon culture. The amphihaploid plants were intermediate between the parents
for most morphological traits. In 46.4% of the PMC’s, only univalents were present. The remainder of the cells had 1–5 bivalents
and 1–2 trivalents. In spite of a detectable frequency of monads (2.6%), dyads (2.6%) and triads (4.5%), the hybrids were
self and cross sterile. 相似文献
545.
546.
The allelic polymorphism and inheritance of MdACS1 and MdACO1 genes were analysed in 28 apple cultivars, which were derived from reciprocal crosses of the following parental pairs: ‘Golden Delicious’ × ‘James Grieve’, ‘Golden Delicious’ × ‘Jonathan’, ‘Cox's Orange Pippin’ × ‘Golden Delicious’, ‘Cox's Orange Pippin’ × ‘Jonathan’. Polymorphisms were detected by PCR and the use of two restriction enzymes (BamH1 and RsaI). In addition, new primers were designed for the further discrimination of MdACO1 alleles. Two alleles of MdACS1 gene (MdACS1‐1 and MdACS1‐2) and three alleles of MdACO1 gene (a, b and c) were detected. Cloning and sequencing of MdACO1 alleles confirmed a high conservation and some differences within the coding regions and helped to reconcile between different numbering systems. Observed segregations confirmed that alleles a, b and c belonged to the MdACO1 gene. It is apparent that polymorphisms within the MdACS1 and MdACO1 genes could aid cultivar genotyping and identification and, furthermore, that the MdACS1‐2/2 genotype is correlated with a long apple storage life. 相似文献
547.
Yam starch films, formulated with yam starch (4.00 g/100 g of solution) and glycerol (1.30 and 2.00 g/100 g of solution) in filmogenic solution, were employed as packaging to extend storage life of strawberries stored at 4 degrees C and 85% RH. The effects of yam starch films on fruits were compared to the effect of PVC (poly(vinyl chloride)) packaging. Starch and PVC films significantly reduced decay of the fruits compared to control. Compared to starch films, PVC presented the better behavior on weight and firmness retention of fruits, especially in the last 7 days of storage. Considering microbiological counts, the shelf life of control fruits was 14 days, and of all packaged samples, stored at same conditions, was 21 days. Two different formulations of yam starch film were tested and had different mechanical properties as a function of glycerol content (1.30 and 2.00 g/100 g of solution) but showed no difference when employed as strawberries packaging. 相似文献
548.
Mato Drenjančević Vladimir Jukić Krunoslav Zmaić Toni Kujundžić 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(8):705-711
The aim of this study was to determine the impact of two different treatments of early defoliation performed before blooming on: grape yield, chemical parameters, polyphenols content, and antioxidant activity of grape and red wine cv. Cabernet Sauvignon from the vineyard located in Ilok, the eastern continental region of Croatia. Two different treatments of leaf removal (LR) were performed: removal of 3 leafs (T1) and 6 leafs (T2) before blooming, together with control (no leaf removal) (T3) during two years (2013 and 2014). Crop yield and average cluster weights per vine were determined. Density, pH and titratable acidity were measured in must, while the total phenols, total anthocyanins and antioxidant activity were measured in the extract of grape skin and produced wine. The analysis of individual anthocyanins in wine was performed by HPLC method. T2 treatment significantly lowered the crop yield and the average cluster weights, and increased total phenols, total anthocyanins, antioxidant activity and most abundant individual anthocyanins in wine. Defoliation did not affect the other chemical parameters in must, grape skin extract and wine. Vintage year is statistically the most significant source of variability for density of must, antioxidant activity in grape skin extract, as well as pH and titratable acidity in wine. This study has showed that the early leaf removal treatment in eastern continental part of Croatia could be used for the production of smaller quantity of high quality Cabernet Sauvignon red wine abundant with anthocyanins. 相似文献
549.
Rafał Strachel Jadwiga Wyszkowska Małgorzata Baćmaga 《Water, air, and soil pollution》2018,229(7):235
Zinc exerts negative effects on soil and contributing to the degradation of soil ecosystems. New solutions for restoring healthy soil activity are therefore needed. The aim of this study was to evaluate the effectiveness of sorbents in the biological remediation of soil contaminated with zinc. A pot experiment was conducted on loamy sand. The tested plant was maize (Zea mays). Soil was contaminated with zinc chloride doses of 0, 100, 300, and 900 mg Zn2+ kg?1 DM soil (dry matter of soil). Alginate, biochar, sepiolite, calcined halloysite, and a molecular sieve were added to soil in amounts corresponding to 2.5% of soil weight to minimize zinc’s potentially toxic effects on the biological properties of soil. The application of zinc stimulated the proliferation of all analyzed microbial groups. Zinc exerted negative effects on the ecophysiological diversity (EP) of fungi and the activity of dehydrogenases, catalase, and acid phosphatase. The applied sorbents modified the microbiological and biochemical properties of soil. In zinc-contaminated soil, alginate, biochar, and molecular sieve increased the counts of organotrophic, oligotrophic, and actinobacteria. Sorbents were not highly effective in promoting fungal growth and exerted varied effects on the activity of soil enzymes. The molecular sieve stimulated the activity of all soil enzymes, excluding β-glucosidase. Alginate minimized the negative influence of zinc on dehydrogenases and acid phosphatase, and biochar—on catalase, sepiolite, and calcined halloysite —on acid phosphatase. By modifying the biological properties of soil, the tested sorbents contributed to an increase in maize yields and a decrease in zinc uptake by maize plants. 相似文献
550.
Neda Tešan Tomić Slavko Smiljanić M. Jović M. Gligorić D. Povrenović A. Došić 《Water, air, and soil pollution》2018,229(9):303
As a result of the destruction of ammunition, mines, and explosive devices by the method of open detonation, the increased concentration of heavy metals is often recorded in the soil of military polygons, which is a serious ecological problem. However, in order to determine the potential risk of such locations to the environment, it is necessary to determine, in addition to the total content, the forms in which the metals are present. In this paper, a sequential extraction method was used to analyze the six fractions of five heavy metals (cadmium, lead, nickel, copper, and zinc) in the soil of the polygon for destruction of ammunition, mines, and explosive devices. Samples were collected from the place of direct detonation (so-called pits) and from the edge of the pit. The aim of this research is determination of metal speciation in order to obtain a better insight in their mobility and risk arising from this. The results showed that heavy metals are predominantly present in the residual, oxide, and organic fractions. Cd and Cu were also significantly present in the mobile fractions due to conducted activities on the polygon. To assess the potential environmental risk of soil, the risk assessment code (RAC) and individual (ICF) and global (GCF) contamination factors were used. According to the RAC, the mobility and bioavailability of the analyzed heavy metals decreases in the following order: Cd?>?Cu?>?Zn?>?Pb?>?Ni. ICF results show low to moderate risk, while GCF results show low risk in terms of heavy metal contamination in the examined area. 相似文献