全文获取类型
收费全文 | 16775篇 |
免费 | 813篇 |
国内免费 | 71篇 |
专业分类
林业 | 1798篇 |
农学 | 423篇 |
基础科学 | 143篇 |
2783篇 | |
综合类 | 2283篇 |
农作物 | 592篇 |
水产渔业 | 1151篇 |
畜牧兽医 | 6796篇 |
园艺 | 485篇 |
植物保护 | 1205篇 |
出版年
2023年 | 107篇 |
2022年 | 161篇 |
2021年 | 244篇 |
2020年 | 336篇 |
2019年 | 272篇 |
2018年 | 400篇 |
2017年 | 380篇 |
2016年 | 408篇 |
2015年 | 358篇 |
2014年 | 401篇 |
2013年 | 845篇 |
2012年 | 896篇 |
2011年 | 1030篇 |
2010年 | 583篇 |
2009年 | 489篇 |
2008年 | 923篇 |
2007年 | 960篇 |
2006年 | 889篇 |
2005年 | 822篇 |
2004年 | 844篇 |
2003年 | 785篇 |
2002年 | 706篇 |
2001年 | 238篇 |
2000年 | 233篇 |
1999年 | 204篇 |
1998年 | 116篇 |
1997年 | 89篇 |
1996年 | 102篇 |
1995年 | 101篇 |
1994年 | 83篇 |
1993年 | 82篇 |
1992年 | 148篇 |
1991年 | 155篇 |
1990年 | 184篇 |
1989年 | 186篇 |
1988年 | 155篇 |
1987年 | 143篇 |
1986年 | 134篇 |
1985年 | 126篇 |
1984年 | 125篇 |
1983年 | 113篇 |
1979年 | 123篇 |
1978年 | 90篇 |
1977年 | 76篇 |
1975年 | 88篇 |
1974年 | 97篇 |
1973年 | 106篇 |
1971年 | 84篇 |
1970年 | 76篇 |
1969年 | 85篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
Evaluation of the cationic trypsinogen gene for potential mutations in miniature schnauzers with pancreatitis
下载免费PDF全文
![点击此处可从《Canadian journal of veterinary research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Micah A. Bishop J?rg M. Steiner Lisa E. Moore David A. Williams 《Canadian journal of veterinary research》2004,68(4):315-318
The purpose of this study was to evaluate the cationic trypsinogen gene in miniature schnauzers for possible mutations. Genetic mutations have been linked with hereditary pancreatitis in humans. Four miniature schnauzers were selected on the basis of a clinical history of pancreatitis. One healthy miniature schnauzer and 1 healthy mixed breed canine were enrolled as controls. DNA was extracted from these canines using a commercial kit. Primers were designed to amplify the entire canine cationic trypsinogen cDNA sequence. A polymerase chain reaction (PCR) was performed and products were purified and sequenced. All sequences were then compared. The healthy control canine, a healthy miniature schnauzer, and the 4 miniature schnauzers with pancreatitis showed identical sequences of the cationic trypsinogen gene to the published sequence. We conclude that, in contrast to humans with hereditary pancreatitis, mutations of the cationic trypsinogen gene do not play a major role in the genesis of pancreatitis in the miniature schnauzer. 相似文献
82.
Adrian Mutlow Ramiro Isaza James W Carpenter David E Koch Robert P Hunter 《Journal of zoo and wildlife medicine》2004,35(4):489-496
Using a crossover study design, the pharmacokinetics of carfentanil and naltrexone after i.v., i.m., and s.c. administration were determined in eight domestic goats (Capra hircus). Serial blood samples were taken up to 120 hr after carfentanil administration, and the plasma drug concentrations were determined using liquid chromatography and mass spectroscopy. All goats were immobilized with 40 microg/kg carfentanil i.m., although the resulting neurologic effects varied considerably. Plasma profiles showed rapid carfentanil absorption and a simple biphasic decline for 12-48 hr. Naltrexone given at 100 mg naltrexone/mg carfentanil 30 min after carfentanil administration produced rapid reversal of immobilization after all routes of administration. Variable fluctuations in the naltrexone plasma concentrations during the first 2.5-3.5 hr were observed, followed by a more consistent biphasic decline. The time to standing was significantly shorter after i.v. compared with s.c. naltrexone, although the time difference (1 min) had little clinical relevance. No statistically significant differences between the naltrexone pharmacokinetic parameters measured for the three routes of naltrexone administration were identified, although the recoveries after i.m. administration were, subjectively, the smoothest. The carfentanil half-life did not differ significantly in the goats given naltrexone by different routes. Although it is currently recommended that the naltrexone dose be divided into s.c. and i.v. portions, this practice does not appear to offer any benefit. 相似文献
83.
Tropical Animal Health and Production - 相似文献
84.
Adherence of Actinobacillus pleuropneumoniae serotype 1 to swine buccal epithelial cells involves fibronectin
下载免费PDF全文
![点击此处可从《Canadian journal of veterinary research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roberto Hamer-Barrera Delfino Godínez V. Idalia Enríquez Sergio Vaca-Pacheco Rodrigo Martínez-Zú?iga Patricia Talamás-Rohana Francisco Suárez-Güemez Mireya de la Garza 《Canadian journal of veterinary research》2004,68(1):33-41
The swine pathogen Actinobacillus pleuropneumoniae serotype 1 was investigated for its ability to adhere to swine, rat, and human buccal epithelial cells (BEC). The highest number of bacteria adhered was to swine BEC. This binding ability was affected by heating, extreme pH, treatment with sodium dodecyl sulfate, ethylenediamine tetraacetate, or periodate, and proteolysis, suggesting that cell-surface glycoproteins participate in adherence and that adherence is based mostly on ionic interactions. Mannose and swine fibronectin may play a direct role in this interaction. Convalescent-phase serum from naturally infected pigs inhibited the adhesion. There was a correlation between bacterial pathogenicity as well as host specificity and the capacity for adherence to swine BEC. Adhesion to swine BEC provides a convenient method to study in vitro the adherence of A. pleuropneumoniae and other pathogens of the pig respiratory tract. 相似文献
85.
Dr. Petra Müller Dorothee Abdel-Kader Joachim Kakau Karl-Heinz Pastrik Luitgardis Seigner 《Gesunde Pflanzen》2004,56(4-5):129-141
Microcosm studies were carried out to test the survival of Ralstonia solanacearum biovar 2 (race 3) in soil at the permanent wilting point (wp) water content and at field capacity (fc) water content and on various material. Soils were placed at permanent ?5°C, 4°C, 15°C and 20°C and weekly fluctuating ?10/0/+10°C and the material at 5, 15 °C, 20°C with relative humidity (rh) uncontrolled or at constant 10% or 90%. In soil, survival was clearly dependent on temperature independent of water content. At 20°C Ralstonia solanacearum could be reisolated up to 364 days, at 15°C up to 290 days, at 4°C up to 209 days and at fluctuating temperatures (?10/0/+10°C) only up to 18 days. The lower the temperature, the more the population declined. At 15°C and 20°C appr. 107 cfu/g soil were detected after 100 days, whereas at ?5°C only 102 cfu/g soil were detected after only 18 days. The pathogen was longer detectable in sandy-clay loam than in lighter sandy soil. It could be longer reisolated at wilting point and the populations did not decline as rapidly as at field capacity. Ralstonia solanacearum could best survive on material surfaces like rubber, plastic and varnished metal with maximum survival of 40 days at 5°C and 10% rh. In general there is a low risk of Ralstonia solanacearum overwintering under European climatic conditions when the fields are cleared of plant debris and the soil is frozen. Contamined material surfaces pose the risk of pathogen transmission to healthy tubers. 相似文献
86.
Identification of irisin immunoreactivity in porcupine (Hystrix cristata) adrenal glands and kidneys
下载免费PDF全文
![点击此处可从《Anatomia, histologia, embryologia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sema Timurkaan Fatih M. Gür Berrin Gençer Tarakçı Mehmet H. Yalçın Mustafa Girgin 《Anatomia, histologia, embryologia》2018,47(5):405-409
Irisin, a novel peptide, was initially been shown to be expressed explicitly in the muscle tissues. We studied the presence of irisin immunoreactivity in porcupine adrenal glands and kidneys. Immunocytochemistry showed that irisin was localised both in the adrenal cortex and adrenal medulla. In organs, irisin immunoreactivity was found in the tubular and collecting system of the nephron. The functional role of irisin in the adrenal gland and kidney has not been precisely yet. However, irisin might have a paracrine and autocrine function as do other locally produced peptides. 相似文献
87.
Radiographic,computed tomographic,and arthroscopic diagnosis of radioulnar incongruence in dogs with medial coronoid disease
下载免费PDF全文
![点击此处可从《Veterinary surgery : VS》网站下载免费的PDF全文](/ch/ext_images/free.gif)
88.
Effects of oral supplementation of probiotic strains of Lactobacillus rhamnosus and Enterococcus faecium on diarrhoea events of foals in their first weeks of life
下载免费PDF全文
![点击此处可从《Journal of animal physiology and animal nutrition》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Christina Ströbel Elena Günther Vladimir Urubschurov Annette Zeyner 《Journal of animal physiology and animal nutrition》2018,102(5):1357-1365
Foal first diarrhoea is one of the most prominent problems in the early life of horses. Probiotics might have the potency to prevent or at least diminish neonatal diarrhoea. We hypothesised that the treatment of foals with probiotic strains of Lactobacillus rhamnosus and Enterococcus faecium starting early after birth and then daily over 2 weeks would prevent or mitigate foal heat diarrhoea. The influence of this probiotic treatment on diarrhoea incidence and growth and health performance of young foals was investigated. Thirty‐four foals were randomly allocated to two groups. From day 1 to 14 of life, the foals received either placebo (PG, n = 16) or the probiotic treatment (TG, n = 18). Clinical examination was performed, and the faeces consistency score (FCS, 1–5; with diarrhoea defined by ≤3) was recorded once per day in weeks 1 and 2 and once weekly in weeks 3–8 of life (WL). The body height was measured at birth and after two and eight WL. Diarrhoea occurred in the 1st WL in 19% and 61% of PG and TG foals respectively. In the 1st WL, diarrhoea lasted 0.3 ± 0.8 and 1.6 ± 1.4 days in PG and TG foals respectively. In the 2nd WL, diarrhoea occurred in 94% and 84% of PG and TG foals, respectively, and lasted for 3.0 ± 1.5 and 3.7 ± 1.6 days respectively. At least two periods of diarrhoea developed in 33% and 65% of PG and TG foals respectively. The TG foals grew slightly slower than the PG foals. The results indicated that the probiotic treatment of neonatal foals as performed in this study was not suitable to reduce diarrhoea within the first two WL, because contrary to the hypothesis, the TG foals suffered more frequently and for longer periods from diarrhoea than the PG foals. 相似文献
89.
UV‐light and dietary vitamin D and their effects on ionized calcium and 25‐OH‐D plasma concentrations in captive gentoo penguins (Pygoscelis papua)
下载免费PDF全文
![点击此处可从《Journal of animal physiology and animal nutrition》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ursina Tröndle Hanspeter W. Steinmetz Simon R. Rüegg Anja Müller Annette Liesegang 《Journal of animal physiology and animal nutrition》2018,102(5):1419-1428
In this study, the effect of ultraviolet (UV) light and dietary vitamin D on calcium metabolism in permanently indoor‐housed gentoo penguins (Pygoscelis papua ) was investigated. The study consisted of three periods, each completed with blood samples to analyse plasma concentrations of 25‐OH‐D, 1,25‐(OH)2‐D, ionized (iCa) and total calcium (tCa). During the first study period (D), animals were housed under routine conditions without UV‐light and fed a diet of different fish species, supplemented with 1,000 IU vitamin D per animal and day. The following study period (Baseline) of 28‐day duration consisted of the same diet without any vitamin D supplementation and without UV‐light. During the study period (UVB) artificial UV‐light was added for 3 weeks. The vitamin D content of fish was measured by high‐performance liquid chromatography. It varied between fish species and between facilities, ranging from no measurable content in capelin (Mallotus villosus ) to 7,340 IU vitamin D/kg original matter (OM) in herring (Clupea spp). The average dietary vitamin D content was 311 IU/kg OM at facility 1 and 6,325 IU/kg OM at facility 2, resulting in a vitamin D intake per animal and day without supplementation of 130 IU (25.5 IU/kg body weight BW) and 2,454 IU (438.2 IU/kg BW) respectively. The supplementation of vitamin D elevated significantly the plasma concentrations of 25‐OH‐D by an intraindividual difference of 15 (range ?2 to 59) nmol/L and tCa by 0.1 (0.0–0.3) mmol/L only at facility 2. The exposure to UV‐light raised the blood concentrations of tCa at facility 2 by 0.15 (0.1–0.2) mmol/L, and of iCa and tCa for females at facility 1 by 0.23 (0.13–0.41) mmol/L and 1.8 (1.1–2.5) mmol/L respectively. No significant influence of the study periods (D) and (UVB) was found for the concentrations of 1,25‐(OH)2‐D at both facilities. 相似文献
90.
Food intake and energy expenditure in growing cats with and without a predisposition to overweight
下载免费PDF全文
![点击此处可从《Journal of animal physiology and animal nutrition》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Vivien Ghielmetti Brigitta Wichert Simon Rüegg Diana Frey Annette Liesegang 《Journal of animal physiology and animal nutrition》2018,102(5):1401-1410
Overweight and obesity are multifactorial diseases caused by an imbalance in energy metabolism. An underlying genetic predisposition is often a factor in these conditions. In the cat breeding family of the Institute of Animal Nutrition at the Vetsuisse Faculty, University of Zurich, a segregating overweight phenotype with a genetic contribution was observed. From this breeding family, 26 kittens were followed from birth up to 8 months of age. During this time, food intake was measured using an automatic feeding station, and energy expenditure was investigated using indirect calorimetry at the ages of 4 and 6 months. Dual‐energy X‐ray absorptiometry (DEXA) was performed and blood glucose, leptin and insulin were measured at the ages of 4, 6 and 8 months. The kittens were also weighed daily for the first 2 weeks of life, every second day until weaning and once per week until 8 months of age. The body condition score (BCS) was evaluated monthly between 2 and 8 months of age. The main finding of this study is that a predisposition to overweight is connected to a higher food intake early in life, with no significant alterations in energy expenditure. The leptin blood levels were related to body fat percentage, and insulin sensitivity did not seem to be affected. 相似文献