全文获取类型
收费全文 | 974篇 |
免费 | 57篇 |
国内免费 | 4篇 |
专业分类
林业 | 48篇 |
农学 | 63篇 |
基础科学 | 5篇 |
146篇 | |
综合类 | 86篇 |
农作物 | 111篇 |
水产渔业 | 87篇 |
畜牧兽医 | 433篇 |
园艺 | 17篇 |
植物保护 | 39篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 35篇 |
2021年 | 17篇 |
2020年 | 25篇 |
2019年 | 19篇 |
2018年 | 23篇 |
2017年 | 33篇 |
2016年 | 27篇 |
2015年 | 43篇 |
2014年 | 34篇 |
2013年 | 67篇 |
2012年 | 57篇 |
2011年 | 94篇 |
2010年 | 59篇 |
2009年 | 52篇 |
2008年 | 62篇 |
2007年 | 46篇 |
2006年 | 65篇 |
2005年 | 42篇 |
2004年 | 39篇 |
2003年 | 46篇 |
2002年 | 36篇 |
2001年 | 25篇 |
2000年 | 21篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1983年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有1035条查询结果,搜索用时 15 毫秒
101.
Comparative effects of organic and inorganic selenium on selenium transfer from sows to nursing pigs
To investigate the effects of supplemental Se on the transfer of Se to nursing pigs when sows are fed diets containing a Se level above the NRC recommendation (0.15 ppm), sows were fed diets containing no supplemental Se or supplemental (0.3 ppm) Se from sodium selenite or Se yeast. A nonSe-fortified corn-soybean meal basal diet with a high endogenous Se content served as the negative control (0.20 to 0.23 ppm Se). Fifty-two sows were fed diets from 60 d prepartum until 14 d of lactation. Six sows per treatment were bled at 60 and 30 d prepartum, at farrowing, and at 14 d postpartum to measure serum Se concentrations. Colostrum was collected within 12 h postpartum, and milk was collected at 14 d of lactation. Blood was obtained from 3 pigs each from 12 litters per treatment at birth and at weaning (d 14), and pooled serum was analyzed for Se and immunoglobulin G concentrations and glutathione peroxidase activity. Regardless of treatment, serum Se in sows declined throughout gestation and gradually increased during lactation. Sows fed Se yeast tended (P < 0.06) to have greater serum Se at farrowing than sows fed unsupplemented diets. Colostrum and milk (d 14) Se concentrations increased (P < 0.01) when sows were fed Se from yeast but not from sodium selenite. At birth, serum Se was increased (P < 0.01) for pigs whose dams were fed Se yeast compared with pigs from sows fed the basal diet. At 14 d of age, there was no difference in serum Se concentration of pigs from dams fed any of the treatments. Pig serum immunoglobulin G concentrations and glutathione peroxidase-1 activity were unaffected by dietary Se source. Supplementation of gestating and lactating sow diets with Se (0.3 ppm) from an organic or inorganic source reduced the number of stillbirths per litter. However, only pigs born to sows fed organic Se (Se yeast) had greater serum Se at birth. Organic Se increased Se concentration of colostrum and 14-d milk to a greater degree than inorganic Se. 相似文献
102.
103.
The veA or velvet gene is necessary for biosynthesis of mycotoxins and other secondary metabolites in Aspergillus species. In addition, veA has also been demonstrated to be necessary for normal seed colonization in Aspergillus flavus and Aspergillus parasiticus. The present study shows that veA homologues are broadly distributed in fungi, particularly in Ascomycetes. The Fusarium verticillioides veA orthologue, FvVE1, is also required for the synthesis of several secondary metabolites, including fumonisin and fusarins. This study also shows that maize plants grown from seeds inoculated with FvVE1 deletion mutants did not show disease symptoms, while plants grown from seeds inoculated with the F. verticillioides wildtype and complementation strains clearly showed disease symptoms under the same experimental conditions. In this latter case, the presence of lesions coincided with accumulation of fumonisins in the plant tissues, and only these plant tissues had elevated levels of sphingoid bases and their 1-phosphate derivatives, indicating inhibition of ceramide synthase and disruption of sphingolipid metabolism. The results strongly suggest that FvVE1 is necessary for pathogenicity by F. verticillioides against maize seedlings. The conservation of veA homologues among ascomycetes suggests that veA could play a pivotal role in regulating secondary metabolism and associated pathogenicity in other fungi. 相似文献
104.
Hyun Cheol Soh Ae Ran Park Sangkyu Park Kyoungwhan Back Jae Bok Yoon Hyo Guen Park Young Soon Kim 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):37-48
To elucidate the functional roles of PR10 genes from two pepper species during plant-pathogen interactions, PR10 genes were isolated from fungal-resistant (Capsicum baccatum var. PBC80) and fungal-susceptible (C. annuum var. Yeoju) pepper fruits infected with anthracnose fungus (Colletotrichum acutatum). Despite strong nucleotide sequence identity, there were significant differences in the patterns of gene expression and
protein accumulation between the genes from the two host species. Induced expression of the PR10 mRNA in PBC80 (bacPR10) was highly maintained from 24 h after infection (HAI) rather than that in Yeoju (annPR10). These mRNA expression patterns were correlated with the level of respective protein that was detected as two or three
bands in each species. Substantial induction of bacPR10 proteins was confirmed by 2D-gel analysis followed by immunoblotting. Immunolocalization study showed that deposition
of bacPR10 was exclusively observed in the pericarp of PBC80 fruits after fungal infection, suggesting functional significance
in defence. Additionally, in vitro analysis of the enzymatic properties of PR10 proteins revealed that recombinant bacPR10 had higher ribonucleolytic activity
and exhibited less sensitivity to proteinase treatment than did annPR10. Taken together, these results support the idea that
relative abundance and prolonged longevity of bacPR10 in PBC80 fruits may contribute to their increased resistance in response
to the anthracnose fungus, as compared with Yeoju fruit. 相似文献
105.
Price DC Chan CX Yoon HS Yang EC Qiu H Weber AP Schwacke R Gross J Blouin NA Lane C Reyes-Prieto A Durnford DG Neilson JA Lang BF Burger G Steiner JM Löffelhardt W Meuser JE Posewitz MC Ball S Arias MC Henrissat B Coutinho PM Rensing SA Symeonidi A Doddapaneni H Green BR Rajah VD Boore J Bhattacharya D 《Science (New York, N.Y.)》2012,335(6070):843-847
106.
Le Dinh Kha Chris E. Harwood Nguyen Duc Kien Brian S. Baltunis Nguyen Dinh Hai Ha Huy Thinh 《New Forests》2012,43(1):13-29
Field trials testing a total of 27 clones of the interspecific hybrid Acacia mangium × A.
auriculiformis and seedling controls of the parental species were established at Ba Vi and Yen Thanh in the north of Vietnam and Long Thanh
in the south. At both Ba Vi and Yen Thanh there were significant (P < 0.001) differences in height and diameter at breast height (DBH) among 22 tested clones at 4 years. At Long Thanh, twelve
hybrid clones did not differ significantly in DBH at age 3 years, but did (P < 0.001) at age 5 years. At the two northern sites the acacia hybrid clones had significantly greater DBH than control seedlots
of the parental species. At Long Thanh, DBH of the hybrid clones and A. mangium was similar, with a genetically improved seedlot of A. mangium displaying the best DBH. Mean wood basic density at breast height of the acacia hybrid clones was 539 kg m−3 at Yen Thanh at age 8 years, and 473 kg m−3 at Long Thanh at age 5 years; density for A. mangium at Long Thanh was only slightly lower than the hybrid clones at 461 kg m−3. Linear regressions of Pilodyn penetration (PP) at breast height on wood basic density explained 60% of the variance in density
of treatments (clones and control seedlots) at Yen Thanh and 36% at Long Thanh. There were significant differences between
hybrid clones in PP at all three trial sites. Clonal DBH performance was not strongly correlated across the three trial sites;
Pearson correlations of clone mean DBH between pairs of sites ranged from −0.47 to 0.20. Clonal rankings for PP were more
stable, with Pearson correlations between pairs of sites ranging from r = 0.71 to 0.78. 相似文献
107.
Type 2 diabetes mellitus is a multisystem disease that is characterized by hyperglycemia and is associated with the dysfunction and failure of various organs. The control of postprandial hyperglycemia is important in the prevention and intervention of type 2 diabetes. Fucoidan has several biological activities in vitro and in vivo. However, the effect of fucoidan on hyperglycemia in non-diabetic and diabetic mice has not been investigated. This study was undertaken to study the effects of different molecular weight forms (5 kilodalton (k), 5-30 k and crude) of fucoidan on oral glucose tolerance tests in non-diabetic mice and on food intake, weight gain, fasting blood glucose and blood biochemistry of db/db mice. Treatment with 200 mg/mL 5 k, 5-30 k and crude fucoidan substantially prevented hyperglycemia according to oral glucose tolerance tests in non-diabetic mice. In addition, fucoidan fractions significantly reduced blood glucose levels in diabetic mice. 相似文献
108.
Yutaka SUZUKI Sang‐Houn SONG Katsuyoshi SATO Kyoung‐Ha SO Astrid ARDIYANTI Shun KITAYAMA Yeon‐Hee HONG Sung‐Dae LEE Ki‐Choon CHOI Akihiko HAGINO Kazuo KATOH Sang‐gun ROH 《Animal Science Journal》2012,83(3):263-267
Accumulating data suggest a relationship between chemerin and energy metabolism. Our group previously described gene cloning, expression analysis and the regulatory mechanism of chemerin and its own receptor in mice and cattle. The objective of the present study was to investigate the physiological effect of chemerin on endocrine changes and energy metabolism in sheep using a biologically stable chemerin analog. The chemerin analog was intravenously administrated (100 or 500 µg/head) to sheep, and plasma insulin and metabolites (glucose, nonesterified fatty acids (NEFA), triglyceride, total cholesterol and high‐density lipoprotein (HDL) cholesterol) were analyzed. The chemerin analog dramatically increased the insulin levels, and glucose levels were decreased. NEFA levels were slightly decreased at 20 min but then increased gradually from 60 to 180 min after analog administration. In addition, injection of the chemerin analog immediately increased triglyceride and total cholesterol but not HDL levels. These results suggested that chemerin analog regulated insulin secretion related to glucose metabolism and the release of triglycerides in sheep in vivo. This study provides new information about endocrine and metabolic changes in response to chemerin in sheep. 相似文献
109.
Breadmaking is a complex process that involves a series of parameters that must be controlled. Rheological measurements are often used to predict the behavior of wheat dough during processing and the quality of the final product. There are many different dietary fiber sources that can be used to enhance the nutritional quality of bread. However, they will affect processing and final product quality. Response surface methodology (RSM) was employed to study the effects of adding different dietary fiber sources (wheat bran, resistant starch, and locust bean gum) on farinographic parameters of wheat flour. The experiments were conducted according to a 23 central composite rotational design (CCRD). With the experimental results or responses (farinographic parameters), the effect of each variable was calculated and the interactions between them were determined. Models that explain the effects of the different fiber sources on water absorption, arrival time, dough development time, and mixing tolerance index of wheat flour were established. The fiber sources interacted for some of the parameters analyzed, demonstrating that if two or more sources of dietary fiber are present in the mix, they might act different to what would be expected of the sum of them. It was also noticed that for most parameters, wheat bran and locust bean gum had a greater influence on farinographic parameters than resistant starch. The simultaneous presence of the three fibers, within the ranges studied, contributed to an increase in water absorption, arrival time, and mixing tolerance index, and to a reduction in departure time and dough stability. 相似文献
110.
Kwon HJ Kim TE Cho SH Seol JG Kim BJ Hyun JW Park KY Kim SJ Yoo HS 《Veterinary microbiology》2002,89(4):303-309
Fowl typhoid caused by Salmonella enterica subsp. enterica serotype Gallinarum biotype Gallinarum is the most important chicken disease in Korea. Due to appearance of new or multiple antibiotics resistances in the recently isolated strains, it was difficult to control the disease using antibiotics in our country. Therefore, the prevalence and genetic contents of class 1 integrons in biotype Gallinarum isolated between 1992 and 2001 were investigated by PCR and direct sequencing, respectively. Out of 90 strains, 35 (39%) carried class 1 integrons. The 1.0, 1.6 and 2.0kbp amplicons were amplified in 32 strains (36%), 2 strains (2%) and 1 strain (1%), respectively. The 1.0, 1.6 and 2.0 kbp amplicons contained one (aadA1a), two (aadB-aadA1b) and three cassettes (dhfrXII-orfF-aadA2), respectively, providing resistances against aminoglycosides (aadA1a, aadA1b, aadB, and aadA2) and trimethoprim (dhfrXII). The integron-carrying strains of biotype Gallinarum appeared in 1996 and acquired additional cassettes in 2000. Although the resistances to ampicillin, tetracycline and chloramphenicol are unrelated to class 1 integrons, relatively high prevalence of integron in biotype Gallinarum may be a dormant threat to the chemotherapy of the disease in the near future because of potency to acquire additional antibiotics resistances. 相似文献