全文获取类型
收费全文 | 249篇 |
免费 | 21篇 |
专业分类
林业 | 20篇 |
农学 | 17篇 |
42篇 | |
综合类 | 25篇 |
农作物 | 9篇 |
水产渔业 | 8篇 |
畜牧兽医 | 128篇 |
园艺 | 3篇 |
植物保护 | 18篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 13篇 |
2013年 | 7篇 |
2012年 | 18篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 4篇 |
2008年 | 13篇 |
2007年 | 20篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1960年 | 1篇 |
排序方式: 共有270条查询结果,搜索用时 15 毫秒
61.
Exogenous N-secretion of the pancreas was investigated with growing pigs with fistulae in the pancreas. For this purpose the two protein sources toasted and untoasted soybean oilmeal were used. After the feeding of untoasted soybean oilmeal a significant increase of the secretion volume and of protein outpour could be observed in contrast to toasted soybean oilmeal within 24 h. The heat-labile soybean trypsin inhibitor also caused an activity increase of the pancreatic enzymes. 相似文献
62.
Angelika M. Vollmar Ursula Preusser AIexander L. Gerbes Wilfried Kraft Rüdiger Schulz 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1995,9(2):105-111
Plasma concentrations of endothelin (ET)-1 and -3 were determined simultaneously in dogs with various pathophysiological conditions, because these peptides may display different pharmacological profiles. The study pays special attention to the characterization of plasma ET immunoreactivity (ET-IR), using high-pressure liquid chromatography (HPLC) analysis with off-line detection by radioimmunoassay (RIA). In most sick dogs evaluated total plasma ET-1-IR concentration did not differ from that of healthy dogs. However, HPLC analysis of their total plasma ET-1 -IR revealed distinct ET-IR profiles. Big-ET-1, which is barely detectable in control dogs, does represent the predominant ET in sick dogs. Regardless of the pathophysiological conditions, considerable amounts of high-molecular weight ET-1-IR, most likely aggregated ET-material, was found consistently. With respect to ET-3, we constantly observed moderately increased concentrations, though no major difference of molecular pattern was evident between healthy and sick dogs. The data show a distinct regulation of ET-1 and ET-3 in dogs. Furthermore, specific molecular forms of ET-IR were found to occur in various diseases. The endothelins may therefore prove to be of diagnostic importance in the pathophysiology of vascular diseases. 相似文献
63.
Rheinhardt Scholtz Gregory A Kiker Gregory D Duckworth Ursula M Scharler Henry G Mwambi Frederick J Venter 《African Journal of Range and Forage Science》2016,33(2):91-100
Important drivers of woody cover in African savannas are rainfall, soil and nutrients, and disturbance factors, such as fire and herbivory. However, very little is known about how these drivers influence woody cover at specific height classes. The main aim of this study was to identify which of these drivers are the best predictors of woody cover at three height classes: shrub (0.75–2.5 m), brush (2.5–5.5 m) and tree (>5.5 m). Percent woody cover estimates were collected using a rapid monitoring technique over 1 700 sites in Kruger National Park, South Africa. Geology (basalt and granite), mean annual rainfall, fire frequency and elephant density were analysed as potential drivers of woody cover. Results indicate that mean annual rainfall was negatively associated with shrub cover, fire frequency was negatively associated with brush cover, and elephant density was negatively associated with tree cover. Patterns of woody cover show that while geology influences the spatial distribution of horizontal woody cover, variation in vertical vegetation structure is created and maintained by top-down disturbance. This provides the first documentation of drivers associated with structurally differentiated woody cover at regional scales. Future studies on woody cover in disturbance-driven environments should not ignore vegetation structure. 相似文献
64.
Effect of the Proximal Abducting Ulnar Osteotomy on Intra‐Articular Pressure Distribution and Contact Mechanics of Congruent and Incongruent Canine Elbows Ex Vivo 下载免费PDF全文
65.
Ursula Bechert J Mark Christensen C Nguyen R Neelkant E Bendas 《Journal of zoo and wildlife medicine》2008,39(2):188-200
The pharmacokinetic parameters of phenylbutazone were determined in 18 elephants (Loxodonta africana and Elephas maximus) after single-dose oral administration of 2, 3, and 4 mg/kg phenylbutazone, as well as multiple-dose administrations with a 4-wk washout period between trials. After administration of 2 mg/kg phenylbutazone, mean serum concentrations peaked in approximately 7.5 hr at 4.3 +/- 2.02 microg/ml and 9.7 hr at 7.1 +/- 2.36 microg/ml for African and Asian elephants, respectively, while 3 mg/kg dosages resulted in peak serum concentrations of 7.2 +/- 4.06 microg/ml in 8.4 hr and 12.1 +/- 3.13 microg/ml in 14 hr. The harmonic mean half-life was long, ranging between 13 and 15 hr and 39 and 45 hr for African and Asian elephants, respectively. There was evidence of enterohepatic cycling of phenylbutazone in Asian elephants. Significant differences (P < 0.0001) in pharmacokinetic values occurred between African and Asian elephants for clearance (27.9 and 7.6 ml/hr/kg, respectively), terminal half-life (15.0 and 38.7 hr, respectively), and mean residence time (22.5 and 55.5 hr, respectively) using 2-mg/kg dosages as an example. This suggests that different treatment regimens for Asian and African elephants should be used. There were no apparent gender differences in these parameters for either elephant species. 相似文献
66.
Dr. Ursula Köhler 《Journal of pest science》1986,59(8):145-147
Zusammenfassung Um Grundlagen für die Behandlung von Kiefernbeständen mit Stehendbefall durch den Großen Waldgärtner zu erarbeiten, wurden im Juli 1984 im Kirchenstiftswald Lindenhardt bei Bayreuth 3 Beobachtungsflächen angelegt. In diesen Flächen wiesen 53% der untersuchten Kiefern Einbohrungen auf. An 19 befallenen Bäumen wurde die vertikale Verteilung der Einbohrungen am Stamm erfaßt. Bestandsbildende Kiefern wurden häufiger als unterdrückte und zurückgebliebene Kiefern befallen; Bäume mit gebrochenem Wipfel wurden nicht bevorzugt attackiert. Von den 105 Kiefern der 3 Flächen wurde bis zum Herbst 1985 kein Baum durch den Großen Waldgärtner zum Absterben gebracht; der durchschnittliche Benadelungszustand der Kiefern veränderte sich über den Beobachtungszeitraum nicht. Anhand der erhobenen Daten wird die waldbauliche Behandlung von Kiefernbeständen bei Waldgärtner-Stehendbefall diskutiert.
Mit einer Abbildung und 4 Tabellen 相似文献
Problems of infesting standing trees byBlastophagus piniperda L.
Since July 1984 three plots of pine forest attacked byBlastophagus piniperda were studied near Bayreuth in Northern Bavaria. 53% of the examined trees were infested; in 19 of the trees the verticale distribution of the bore-holes was studied. The stand forming pines were more often infested than the suppressed ones (and the laggards), and trees with broken crowns were not preferred to others by the bark beetles. Up to autumn 1985 none of the 105 trees in the three plots were killed byB. piniperda. The average state of foliation of the pines did not change during the observation period. Based on the results of this study silvicultural measures in the management of pine forests attacked byB. piniperda are discussed.
Mit einer Abbildung und 4 Tabellen 相似文献
67.
BACKGROUND: Increased rates of overweight/obesity have been reported in recent years in developed countries. This population study of healthy subjects evaluated the changes in overweight/obesity prevalence in 2003, compared with 1993, and determined the association of age, sex and leisure-time activity with body mass index (BMI), fat-free mass index (FFMI) and fat mass index (FMI). DESIGN: Two transversal samples of convenience. PARTICIPANTS: Healthy volunteers (1993, n = 802; 2003, n = 1631). METHODS: Fat-free mass was determined using the bioelectrical impedance multiple regression equation. Multivariable linear regression, including confounding variables (age, sex, leisure-time activity), was used to model the body composition evolution between the 1993 and the 2003 subjects. RESULTS: BMI and FMI were higher in 2003 than in 1993, P < 0.001. FFMI was not higher in 2003 than in 1993, P = 0.38. More subjects were overweight/obese in 2003 than in 1993 (27.5 versus 17.2%, chi-square P < 0.001), and had a high FFMI (30.2 versus 21.8%, chi-square P < 0.001) and high FMI (28.0 versus 20.3%, chi-square P < 0.001). Multivariate linear regressions showed that leisure-time activity was negatively, and sex, age and inclusion year were positively associated with BMI, FFMI and FMI (the exception was a negative association with sex) (P < 0.001). CONCLUSION: Overweight prevalence increased between 1993 and 2003 in a Swiss city, and was associated with a higher fat mass. This observation remained statistically significant after adjustment for age, sex and leisure-time activity. 相似文献
68.
69.
Speltoid spikes are characterized by pyramidal spike morphology featuring an elongated rachis and tenacious glumes. Speltoids
are considered undesirable spike aberrants in wheat breeding leading to increased heterogeneity within a cultivar candidate.
As a consequence, the presence of speltoids may result in rejection of a cultivar candidate during official field trials or
denial of cultivar certification during seed multiplication. A reliable method is, thus, required to assess the occurrence
of speltoids, early on in a wheat breeding program. The domestication gene Q located on the long arm of wheat chromosome 5A is known to suppress the speltoid phenotype in wheat. Here, a quantitative
pyrosequencing assay was developed to distinguish between normal wheat plants, which possess two copies of the Q allele, and aberrants, which are either aneuploids lacking the correct number of chromosome 5A copies or plants which carry
the primitive q allele. An accurate and reproducible determination of the Q gene copy number was achieved for different wheat genotypes based on homoeologous sequence quantification with two primer
combinations at the Q locus. Single plants with one to four copies of the Q allele could be detected by quantitative pyrosequencing which corresponded to the occurrence of speltoid (1 Q allele), normal (2 Q alleles), and compact (more than 2 Q alleles) spikes. Q and q specific alleles could be differentiated at SNP position 2299 of the Q gene. This SNP is assumed to be related to the emergence of free-threshing wheat forms. To our knowledge this is the first
report for detection of aneuploids and differentiation of Q alleles in bread wheat using pyrosequencing technology. In future, quantitative pyrosequencing assay can be applied in wheat
breeding programs to carry out marker-assisted selection against the presence of speltoid spike aberrants. 相似文献
70.
Discoid lupus erythematosus (DLE) is a common canine autoimmune disease that usually manifests as a localized ulcerative and scarring nasal dermatitis. We report herein a generalized variant of canine DLE successfully treated with the antimalarial immunomodulator hydroxychloroquine (HCQ). A 9-year-old hairless Chinese crested dog was presented with annular and polycyclic hyperpigmented and scaly skin lesions with central erosions, hypopigmentation and/or scarring on the trunk, neck and lateral extremities. Associated systemic signs were not seen. The clinical diagnosis of generalized DLE was supported by the demonstration of lymphocyte-rich interface dermatitis with epidermal atrophy and dermo-epidermal deposition of immunoglobulins and activated complement. As for human DLE, treatment was initiated with HCQ at 5 mg/kg once daily along with 2 weeks of 0.1% tacrolimus ointment and restriction of sun exposure. Over the following year, complete remission was maintained with HCQ at 5 mg/kg orally once daily with the exception of three relapses; two occurred during treatment induction and the third arose when the frequency of HCQ administration was reduced to every other day. Disease flares were controlled with 0.1% tacrolimus ointment alternating with 0.1% prednicarbate cream once daily for 5-10 days. Altogether, adverse drug events were not seen with this regimen. In summary, clinically, histologically and immunologically, this dog's disease mirrored the generalized discoid variant of chronic cutaneous lupus erythematosus of humans. The apparent benefit of HCQ, its safety and low cost warrant future investigations of its use for treatment of canine cutaneous lupus variants. 相似文献