首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   440篇
  免费   13篇
林业   10篇
农学   14篇
基础科学   2篇
  199篇
综合类   39篇
农作物   9篇
水产渔业   9篇
畜牧兽医   157篇
园艺   8篇
植物保护   6篇
  2021年   4篇
  2018年   7篇
  2017年   7篇
  2016年   7篇
  2015年   6篇
  2014年   9篇
  2013年   11篇
  2012年   13篇
  2011年   16篇
  2010年   13篇
  2009年   11篇
  2008年   20篇
  2007年   26篇
  2006年   12篇
  2005年   12篇
  2004年   12篇
  2003年   15篇
  2002年   4篇
  2001年   8篇
  2000年   7篇
  1999年   4篇
  1998年   7篇
  1996年   5篇
  1995年   5篇
  1994年   6篇
  1993年   3篇
  1992年   7篇
  1991年   6篇
  1990年   22篇
  1989年   13篇
  1988年   8篇
  1987年   16篇
  1986年   13篇
  1985年   12篇
  1984年   14篇
  1983年   9篇
  1982年   7篇
  1981年   6篇
  1980年   5篇
  1979年   6篇
  1978年   6篇
  1977年   7篇
  1976年   5篇
  1975年   9篇
  1974年   3篇
  1973年   4篇
  1972年   3篇
  1971年   5篇
  1968年   4篇
  1967年   5篇
排序方式: 共有453条查询结果,搜索用时 265 毫秒
61.
Although a multitude of effective liver function tests are avaiable for use in animals, a variety of modifications of currently used tests have been recently reported. In addition, newer procedures now used in human medicine may also provide unique insights into assessing and detecting acquired hepatic disorders in animals. Examples of new procedures are: assessing microsomal mixed function oxidase activity by plasma caffeine clearance; estimating the extent of active hepatic fibrogenesis through serum procollagen-III peptide levels; determining hepatic blood flow and functional mass by the galactose elimination capacity; detecting primary hepatocellular cancer through serum or urinary ligandin levels; and to estimate the liver's maximal capacity to excrete indocyanine green independent of blood flow. In evaluating drugs as to their hepatotoxicity, function tests should be included in the liver profile which measure specific metabolic alterations unique to the compound under study.This work was supported by USPHS-NIH grants RR00169 and AM32297.  相似文献   
62.
Acute gastric dilatation and volvulus with dilatation were produced in 11 dogs anesthetized with halothane. Blood samples were taken during these procedures for biochemical analyses. Serum potassium did not change significantly during the experimental procedure, but there was a significant increase (p<0.05) after release of the dilatation with volvulus. Renal function was impaired with significant increases (p<0.05) in the serum concentration of urea nitrogen, phosphorus, and creatinine. Evidence of cellular damage was reflected by a significant elevation (P<0.05) in glutamic-oxaloacetic transaminase activity. Serum glucose concentration increased significantly (P<0.05) during experimental gastric dilatation and dilatation with volvulus.  相似文献   
63.
Glycosylated albumin and glycosylated protein in serum were measured in 4 well-controlled diabetic dogs, 4 poorly controlled diabetic dogs, and 21 nondiabetic dogs. Concentrations of both glycosylated components in the well-controlled dogs were similar to those in nondiabetic dogs. Serum concentrations of glycosylated albumin and protein in the poorly controlled diabetic dogs were higher (P less than 0.001) than those of the nondiabetic and well-controlled diabetic dogs. Because of the essentially irreversible nature of the glycosylation reaction and the relatively short turnover time of albumin and other serum proteins, measurements of glycosylated serum components may provide an index of glycemia during the preceding days or weeks.  相似文献   
64.
65.
66.
67.
Arterial and venous blood gas tensions and pH were determined in 8 dogs during a control interval, while adrenal deficient, and following replacement therapy with corticosteroids. Additionally, erythrocyte 2,3-diphosphoglycerate (DPG) values were measured, and oxygen tension (mm of Hg) when hemoglobin is half-saturated with oxygen (P50) values were calculated. Mixed venous oxygen tension (PVO2), but not arterial oxygen tension (Pao2), decreased significantly (P less than 0.001) during adrenal insufficiency. This change was reflected in a significantly decreased (P less than 0.001) venous oxygen content and a significant increase (P less than 0.001) of the arterial-venous oxygen content difference. Other changes during adrenal insufficiency were nonsignificant decreases in DPG and P50 values. Treatment with corticosteroids for 2 to 3 days resulted in a significant (P less than 0.001) increase in DPG concentrations, a significant (P less than 0.025) increase in P50, and a reduction in the arterial-venous oxygen content difference compared with those values found in the adrenal-deficient dog.  相似文献   
68.
Zusammenfassung Die Korrelationsstruktur kultivierterSorghum-Sippen wurde mittels Berechnungen von Koeffizienten der Divergenz der Korrelationen (KDK) und Ähnlichkeitskoeffizienten (ÄK) untersucht. Dafür wurden22 Merkmale an 54 nach dem System vonJakusevkij (1969) 7 Kulturarten zugerechnetenSorghum-Sippen geprüft. Besonders wurden morphologische Merkmale der vegetativen Sphäre und ökologische Merkmale untersucht, die gewöhnlich für dieSorghum-Systematik, die sich auf Merkmale der Organe der generativen Sphäre gründet, keine große Rolle spielen.Nach den Ergebnissen von KDK und ÄK erweist sich der S.durra-Komplex, der deutlich viele Kulturpflanzenmerkmale zeigt, als besonders hoch entwickelt. Ihm sehr ähnlich ist derS. nervosum-Komplex. DerS. guineense-Komplex dagegen steht weit von diesen Artenkomplexen, die sich im Zentrum der Diagramme befinden (Abb. 3 und 4), entfernt. Seine Merkmale entsprechen im Durchschnitt auch mehr dem Wildtyp.Beim Studium der Korrelationsstruktur war es möglich, anhand der von uns gewählten Merkmale manche Artenkomplexe deutlich zu unterscheiden. Es wird festgestellt, daß einige der in neuerer Zeit zu einer Art zusammengefaßten kultiviertenSorghum- Sippen als eigenständige Arten aufgefaßt werden können.
Remarks on some cultivatedSorghum races on the basis of their correlation structure
Summary The correlation structure of cultivatedSorghum races was studied by using the coefficient of divergence of correlations (KDK) and the coefficient of similiarity (ÄK). In 54Sorghum races (table 1), which were grouped into 7 species (table 2) according toJakuevskij (1969),22 characters (table 3) were studied. Above all morphological characters from vegetative organs and ecological characters were tested, which do not play an important role for the systematics ofSorghum, because this is founded on characters from generative organs mainly. The results from KDK (fig. 3) and ÄK (fig. 4) show that theS. durra — complex is highly developed and has many characters of cultivated plants. TheS. nervosum-complex is similar to it. Whereas theS. guineense — complex can be found at the periphery of the diagrams (fig. 3 and 4) far away from the already mentioned complexes, which are located in the centres of the diagrams. The characters of theS. guineense — complex are similar to the wildSorghums mainly.From the study of the correlation structure it was possible to separate some of the species — complexes very clearly by using the above mentioned characters. We can state that some of the cultivatedSorghums, which are now often united into one species, may be regarded as good species.

Sorghum
0 ( ) (ÄK). 22 ( . 3) 54 (. 1) (1969) 7 (. 2). , , . , . ÄK , S. durra . S. nervosum. ,S. guineense (. 3 4) . . , . , .


Die Arbeit entstand während eines längerfristigen Arbeitsaufenthaltes. Mein Dank gilt dem VIR für Arbeitsmöglichkeiten und Material.  相似文献   
69.
70.
Fifteen dogs with hemangiosarcoma were treated with a combination of vincristine, doxorubicin, and cyclophosphamide after incisional or excisional biopsy. The median survival for all fifteen dogs was 172 days (mean survival = 316 days). The median survival for those dogs with splenic hemangiosarcoma was 145 days (mean survival = 271 days) as compared with previously published median survival times in dogs with splenic hemangiosarcoma treated with surgery alone of 19 to 65 days. Toxicities included neutropenia (11/15), severe gastroenteritis (4/15), cardiotoxicity (3/15), and sepsis (2/15). The authors conclude that vincristine, doxorubicin, and cyclophosphamide chemotherapy may be an efficacious treatment modality in dogs with hemangiosarcoma and is associated with acceptable toxicity.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号