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   99篇
  免费   1篇
农学   5篇
  2篇
综合类   16篇
水产渔业   1篇
畜牧兽医   72篇
植物保护   4篇
  2020年   1篇
  2016年   2篇
  2013年   3篇
  2012年   2篇
  2011年   5篇
  2010年   3篇
  2009年   5篇
  2008年   4篇
  2007年   2篇
  2006年   1篇
  2004年   1篇
  2001年   1篇
  1999年   1篇
  1998年   9篇
  1997年   3篇
  1996年   7篇
  1995年   2篇
  1994年   4篇
  1993年   9篇
  1992年   5篇
  1991年   5篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   3篇
  1985年   2篇
  1983年   2篇
  1980年   1篇
  1979年   3篇
  1974年   1篇
  1957年   4篇
  1956年   2篇
  1948年   1篇
排序方式: 共有100条查询结果,搜索用时 15 毫秒
61.
Pore fluids from the upper 60 meters of sediment 3000 meters below the surface of the tropical Atlantic indicate that the oxygen isotopic composition (delta18O) of seawater at this site during the last glacial maximum was 0.8 ± 0.1 per mil higher than it is today. Combined with the delta18O change in benthic foraminifera from this region, the elevated ratio indicates that the temperature of deep water in the tropical Atlantic Ocean was 4°C colder during the last glacial maximum. Extrapolation from this site to a global average suggests that the ice volume contribution to the change in delta18O of foraminifera is 1.0 per mil, which partially reconciles the foraminiferal oxygen isotope record of tropical sea surface temperatures with estimates from Barbados corals and terrestrial climate proxies.  相似文献   
62.
Sheep were immunised with Corynebacterium pseudotuberculosis toxoid formulated as a monocomponent vaccine with aluminium adjuvant or in combination with 5 clostridial antigens, and also in the combined form with sodium selenate. Immunised and control sheep were experimentally infected 16 days after vaccination and slaughtered and inspected after a further 3 months to determine their resistance to infection. All 3 vaccines afforded an equal and high level of protection; 91% of vaccinated sheep exhibiting no lesions of caseous lymphadenitis compared with 51.5% affected sheep in the control group. Average lesion counts were 1.2 per affected vaccinated sheep and 4.5 per affected control sheep. Antitoxin responses to the clostridial toxoids incorporated in the combined vaccines were not affected by inclusion of the C pseudotuberculosis toxoid or the sodium selenate.  相似文献   
63.
Effects of neodymium:yttrium aluminum garnet (Nd:YAG) laser irradiation on equine endometrium were evaluated In vitro and in six mares with endometrial cysts. The Nd:YAG laser was applied to six endometrial sites, in each of five uterine specimens, with power densities of 5659 to 33,954 J/cm2. Depth of tissue ablation was measured and graded on histologic sections of the tissue lesions. Power density had a significant effect on the depth of tissue ablation (p < .001). Grade 3 lesions (full-thickness ablation of the endometrium) were created with energy densities of 16,977 to 33,954 J/cm2. Six mares had endometrial cysts treated by photoablation. Two of the four mares that were reproductively sound but barren, despite appropriate breeding, produced foals after treatment. One mare remained reproductively unsound after treatment, and another mare that was treated postpartum was bred successfully.  相似文献   
64.
The magnetometer and electron reflectometer experiment on the Lunar Prospector spacecraft has obtained maps of lunar crustal magnetic fields and observed the interaction between the solar wind and regions of strong crustal magnetic fields at high selenographic latitude (30 degreesS to 80 degreesS) and low ( approximately 100 kilometers) altitude. Electron reflection maps of the regions antipodal to the Imbrium and Serenitatis impact basins, extending to 80 degreesS latitude, show that crustal magnetic fields fill most of the antipodal zones of those basins. This finding provides further evidence for the hypothesis that basin-forming impacts result in magnetization of the lunar crust at their antipodes. The crustal magnetic fields of the Imbrium antipode region are strong enough to deflect the solar wind and form a miniature (100 to several hundred kilometers across) magnetosphere, magnetosheath, and bow shock system.  相似文献   
65.
Oral clindamycin disposition after single and multiple doses in normal cats   总被引:1,自引:0,他引:1  
Eighteen normal cats were randomly allocated into three treatment groups and dosed with clindamycin aqueous solution for 10 days at a dosage rate of: (1) 5.5 mg/kg b.i.d.; (2) 11 mg/kg b.i.d.; or (3) 22 mg/kg once daily. Serum disposition of clindamycin was determined after the first and last dose of clindamycin was given, and was analyzed using model-independent pharmacokinetics by both the trapezoidal rule method and the predictive equation method. Complete blood counts and clinical chemistries were determined before and after the study. The trapezoidal rule method produced similar mean results with much less variance than the predictive equation method. Mean residence time was longer (P less than 0.05) after the high dose (393 +/- 77 min) than after either the low or medium doses (276 +/- 51 and 274 +/- 45 min, respectively). Oral volume of distribution (Vd(ss)/F) after the high dose (3.06 +/- 0.92 l/kg) was larger (P less than 0.05) than that after the low or medium doses (1.62 +/- 0.30 and 1.76 +/- 0.53 l/kg, respectively). Oral Vd(ss)/F was significantly smaller (P less than 0.001) after the last dose than after the first dose when analyzed by treatment group. Significant (P less than 0.01) decreases in the leukogram and erythrogram were observed, due to the large amount of blood collected for drug analysis. No clinical signs of drug intoxication were observed, and no drug-related necropsy findings were found.  相似文献   
66.
67.
68.
Abstract A pruritic maculopapular eruption with clinical and histological features similar to urticaria pigmentosa of humans is reported in three related Sphinx cats. All cats shared the same grandsire, had a juvenile onset of disease, and demonstrated similar historical, clinical and histological findings. Physical examination revealed widespread bilaterally symmetrical, erythematous, partially coalescing, crusted macules and papules on the trunk, limbs, neck and head. A few macules exhibited a dark brown pigmentation. Dermatographism could not be elicited in any of the cats. Histological examination of papules revealed the présence of a perivascular to diffuse dermal and subcutaneous infiltrate of well-differentiated mast cells. In one cat where systemic involvement was pursued, evidence of internal disease was not found. Resumen Se describe en 3 gatos esfinge emparentados una erupción maculopapular pruritica con caracteristicas clinicas e histológicas similares a la urticaria pigmentosa en la especie humana. Todos los gatos compartian el mismo abuelo, desarrollaron la enfermedad en edad juvenil y mostraron hallazgos históricos, clinicos e histológicos similares. El examen fisico mostró pápulas y máculas costrosas, eritematosas, parcialmente unidas, generalizadas, bilaterales y simétricas localizadas en tronco, extremidades, cuello y cabeza. Algunas máculas mostraban una pigmentación marronácea oscura. No pudo provocarse dermatografismo en ninguno de los gatos. El examen histológico de las pápulas mostró la presencia de un infiltrado dérmico y subcutáneo perivascular a difuso compuesto por mastocitos bien diferenciados. No se encontró enfermedad sistémica en un animal en el que se evaluó esta posibilidad. [Vitale, C.B., Ihrke, P.J., Olivry, T., Stannard, A.A. Feline urticaria pigmentosa in three related Sphinx cats. (Urticaria pigmentosa felina en 3 gatos esfinge emparentados.) Veterinary Dermatology 1996; 7 : 227–233.] Résumé Les auteurs décrivent chez 3 chats Sphynx apparentés une eruption maculopapuleuse présentant des similitudes cliniques et histologiques avec l'urticaire pigmentaire humaine. Les 3 chats ont le même grandpère, présentent une apparition précoce des symptômes, et, une anamnèse, une clinique et une histologie similaires. L'examen clinique révèle des macules et des papules croûteuses à large distribution bilatérale et symétrique, érythèmateuses, partiellement coalescentes, sur le tronc, les membres, le cou et la tête. Quelques macules montrent une pigmentation brun foncé. La présence d'un dermographisme n'a pu être démontré chez aucun des chats. L'examen histologique des papules révèle la présence d'un infiltrat dermique et sous cutané périvasculaire à diffus de mastocytes bien différenciés. La recherche d'une atteinte systémique chez un des chats n'a pas montré d'atteinte interne. [Vitale, C.B., Ihrke, P.J., Olivry, T., Stannard, A.A. Feline urticaria pigmentosa in three related Sphinx cats. (Urticaire pigmentaire féline chez 3 chats Sphynx apparentés.) Veterinary Dermatology 1996; 7 : 227–233.] Zusammenfassung Es wird über eine juckende makulopapuläre Eruption mit klinischen und histologischen Befunden, die der Urticaria pigmentosa des Menschen ähneln, bei drei verwandten Sphinx-Katzen berichtet. Alle Katzen hatten den selben Großvater, zeigten einen Krankheitsbeginn im Jugendalter und wiesen ähnliche Befunde in der Vorgeschichte, Klinik und Histologie auf. Die klinische Untersuchung zeigte weit verteilte, bilateral symmetrische, erythematöse, teilweise koaleszierende verkrustete Maculae und Papeln am Rumpf, Gliedmaßen, Hais und Kopf. Einige maculae wiesen eine dunkelbraune Pigmentierung auf. Dermatographismus konnte bei keiner der Katzen ausgelöst werden. Die histologische Untersuchung der Papeln zeigte die Anwesenheit eines perivaskulären bis diffusen dermalen und subkutanen Infiltrates von gut differenzierten Mastzellen. Bei einer Katze mit systemischen Erscheinungen konnte die Ursache der inneren Erkrankung nicht gefunden werden. [Vitale, C.B., Ihrke, P.J., Olivry, T., Stannard, A.A. Feline urticaria pigmentosa in three related Sphinx cats (Feline Urticaria pigmentosa bei drei verwandten Sphinx-Katzen). Veterinary Dermatology 1996; 7 : 227–233.]  相似文献   
69.
We describe a novel application of “forensic” genetics to study a key demographic event in a population of wild gorillas. We used microsatellite genotyping and non‐invasively collected DNA samples to identify one individual western lowland gorilla as being most likely to have caused the death of another in Lopé National Park, Gabon. Data from relatively few genotypes permitted the identification of female transfer events and the interpretation of individual behavior that was previously impossible using observational methods, thus providing rare behavioral data on an elusive forest‐dwelling species. Importantly, this study highlights the need for future studies of dispersal and local population structuring in forest populations, and more accurate population census methods. Genetic studies focusing on individual identification may play a valuable role in future gorilla conservation efforts.  相似文献   
70.
Single or multiple rib resection was performed in 40 dogs for the treatment of primary osteosarcoma or chondrosarcoma. The resulting thoracic wall defect was closed with polypropylene (12 dogs), primary muscle flap (16 dogs), diaphragmatic advancement (10 dogs), or a combination (2 dogs). Few immediate (less than 2 weeks) postoperative complications were observed. Twenty dogs with osteosarcoma had a median survival time of 3.3 months (range, 0.5 to 23 months), with a 20% 6-month survival time. Metastases occurred in all the dogs. Fourteen dogs with chondrosarcoma followed up longer than 2 weeks had a median survival time of 10.7 months (range, 0.5 to 36 months) with a 64% 6-month survival time. Eight dogs developed metastases, five died from concurrent disease, and one dog is alive. Dogs with chondrosarcoma survived significantly longer than dogs with osteosarcoma. Survival time was not related to tumor size or number of ribs resected.  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