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   110篇
  免费   7篇
林业   6篇
农学   3篇
  4篇
综合类   14篇
农作物   3篇
水产渔业   5篇
畜牧兽医   75篇
园艺   2篇
植物保护   5篇
  2021年   2篇
  2020年   3篇
  2019年   1篇
  2018年   2篇
  2017年   1篇
  2016年   3篇
  2015年   2篇
  2014年   3篇
  2013年   4篇
  2012年   3篇
  2011年   2篇
  2010年   2篇
  2009年   3篇
  2008年   5篇
  2007年   4篇
  2006年   4篇
  2005年   4篇
  2004年   6篇
  2003年   10篇
  2002年   1篇
  2001年   10篇
  2000年   1篇
  1999年   4篇
  1998年   6篇
  1997年   2篇
  1996年   1篇
  1992年   5篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1984年   1篇
  1979年   1篇
  1978年   1篇
  1975年   1篇
  1973年   1篇
  1972年   3篇
  1971年   2篇
  1969年   1篇
  1967年   1篇
  1960年   2篇
排序方式: 共有117条查询结果,搜索用时 31 毫秒
1.
Two serological tests (indirect immunofluorescence and enzyme-linked immunosorbent assay) were developed for the detection of fetal antibody to Chlamydia psittaci. Fetal blood and thoracic fluid from 126 field cases of suspected ovine chlamydial abortion were examined using both tests. Placenta and fetal tissues (lung, liver, and kidney) from the same animals were also examined by the following conventional diagnostic methods: isolation in McCoy cells, detection of chlamydial lipopolysaccharide (LPS), modified Ziehl-Nielsen staining, and direct fluorescent antibody staining of chlamydia in frozen cryostat sections. Seventy cases were positive by fetal serology, and of these, 68 were also positive by isolation and/or LPS detection. The remaining 56 cases had negative fetal serology, and of these, 39 were positive by isolation and/or LPS detection. Results indicate that fetal serology, although less sensitive than either isolation in McCoy cells or detection of chlamydial LPS antigen, may be of particular use when placenta is not available.  相似文献   
2.
Objective: To correlate the sodium chloride dosage and the serum sodium concentration to clinical signs, to determine if the dosage of homemade play dough (and, therefore, sodium chloride) is the most reliable way to predict clinical signs and prognosis, and to review previously reported treatment options. Design: Retrospective case series. Animals: Fourteen dogs with a history of homemade play dough ingestion. Procedure: Cases were examined for each animal's signalment including body weight, age, approximate amount of play dough ingested, the estimated sodium chloride dosage, clinical signs, serum sodium concentration, and outcome when available. The literature was reviewed to determine pathophysiology and treatment regimens. Results: Twelve of 14 dogs (86%) that ingested homemade play dough showed clinical signs. Vomiting (9 of 14, 64%), polydipsia, and seizures (4 of 14 each, 29%) were the most common signs followed by polyuria, tremors (3 of 14 each, 21%), and hyperthermia (2 of 14, 14%). The lowest calculated dosage associated with objective clinical signs was 1.9 g/kg. Seizures were reported in all animals with serum sodium levels greater than 180 mEq/L. Conclusions and clinical relevance: Homemade play dough ingestion can be a serious and life‐threatening problem. Many factors can contribute to the toxicity of homemade play dough. This study indicates that the serum sodium concentration is a more reliable indicator of the clinical course of the toxicity rather than the amount of play dough and, therefore, the dosage of sodium chloride ingested. Treatment should be based on a clinical evaluation of the patient and laboratory results, and consists of controlling seizures, reducing serum sodium concentrations slowly, and supportive care.  相似文献   
3.
Cholera toxin (Ctx) is a powerful mucosal adjuvant with potential applications for oral vaccination of swine. Dendritic cells (DC) play a key role in the decision between immunity and tolerance, and are likely target cells for mediating Ctx functions in vivo. Therefore, we examined the capacity of Ctx to enhance stimulatory activity of porcine monocyte-derived DC (MoDC). Ctx promoted the development of a semi-mature DC phenotype, with decreased levels of MHC class II and CD40, but increased CD80/86 expression. These changes were associated with activation of extracellular signal-regulated kinase (ERK), but not NFkappaB or c-Jun N-terminal kinase (JNK). Functionally, Ctx-priming greatly diminished T cell stimulatory capacity both in antigen-specific and superantigen-induced proliferation assays. The lower proliferation rate was not due to increased apoptosis of either DC or T cells. Ctx suppressed TNFalpha secretion by MoDC, but induced IL-10 production. The observed effects on T cell proliferation could only be partially mimicked by IL-10 alone. However, addition of recombinant TNFalpha to co-cultures of Ctx-primed MoDC and lymphocytes restored lymphocyte proliferation in a concentration-dependent manner. Ctx-primed DC were not actively tolerogenic, since they could not suppress proliferative T cell reactions induced by untreated DC.  相似文献   
4.
5.
Porcine Alv-Mphi from bronchoalveolar lavages were tested for their function in an in vitro foot-and-mouth disease virus (FMDV)-specific lymphoproliferative recall response. The Alv-Mphi were seen to be poor accessory cells when compared with peripheral blood monocytes. This poor capacity was evident despite an efficient expression of SLA-DR region antigens, and other co-stimulatory adhesion molecules. It was noted that Alv-Mphi secrete relatively little interleukin 1 (IL-1beta), with or without LPS induction, even though mRNA for the cytokine could be detected. In contrast, blood monocytes with their effective accessory activity were potent secretors of IL-1. Although this IL-1beta would be important with respect to the accessory capacity of monocytic cells, it was noted that the absence of bioactive IL-1 from the Alv-Mpi cultures was not solely responsible for their poor accessory function. In fact, the Alv-Mphi produced factors which not only inhibited IL-1 bioactivity, but were also responsible for a clear suppression of lymphoproliferation. This suppressor activity was dependent on the type of monocytic cell present in the culture, being more prominent when "scavenger" phagocytes were present. Thus, the major role of Alv-Mphi s not as an accessory cell akin to monocytes, but as both a scavenger cell, related to Mphi derived from monocytes in the absence of inflammatory signals, and an immunoregulatory cell.  相似文献   
6.
This article analyzes the relationship between forest resources, refugees, and the host population. The findings of the research suggest that the host population are heavily dependent on the local forest for their daily needs such as fuelwood, timber, grazing area, fodder for domestic animals, foods, and medicine in addition to cultural and esthetic needs. The forest has also been relied upon for agricultural needs such as manufacture of agricultural tools, maintenance of irrigation water systems, erosion control, and fertilizer needs. The forest was under a sustained demand as any other Terai forest of Nepal. After the arrival of refugees in 1992, the demand for forest resources increased substantially. Initially, the construction of the refugee camps decreased the total forest area and also required some felling of trees. More significantly, the refugees themselves became active users of the forest resource, which generated extra pressure on the forest and created scarcity of forest resources. Before the arrival of the refugees, forest management and monitoring of illegal use of the forest resources were carried out by the government through its local forester office. The local residents were active users of the forest resources, but were passive in managing and maintaining the forest resource. However, competition from the refugees instilled a desire in the local population to safeguard and protect the dwindling resource against the external threat by creating the Humse Dumse Community Forest.  相似文献   
7.
Wood Science and Technology - Tension wood, when kiln-dried, is likely to deform hugely, which is probably caused by a gelatinous layer of the gelatinous fiber. To elucidate the mechanism behind...  相似文献   
8.
Tanger  S. M.  Blazier  M. A.  Holley  A. G.  McConnell  T. E.  Vanderschaaf  C.  Clason  T. R.  KC  Dipesh 《New Forests》2021,52(2):217-235
New Forests - Competition suppression within loblolly pine plantations (Pinus taeda L.) is typically carried out within the first 2 years of a plantation, but competition control for longer...  相似文献   
9.
The objective was to compare populations of antral and pre‐antral ovarian follicles in Bos indicus and Bos indicustaurus cows with high and low antral follicle counts. Nelore (Bos indicus, n = 20) and Nelore X Angus (1/2 Bos indicus‐taurus, n = 20) cows were subjected to follicular aspiration without regard to the stage of their oestrous cycle (day of aspiration = D0) to remove all follicles ≥3 mm and induce growth of a new follicular wave. Ovaries were examined by ultrasonography on D4, D19, D34, D49 and D64, and antral follicles ≥3 mm were counted. Thereafter, cows were assigned to one of two groups: high or low antral follicular count (AFC, ≥30 and ≤15 antral follicles, respectively). After D64, ovaries were collected after slaughter and processed for histological evaluation. There was high repeatability in the numbers of antral follicles for all groups (range 0.77–0.96). The mean (±SD) numbers of antral follicles were 35 ± 9 (Bos indicus) and 38 ± 6 (Bos indicustaurus) for the high AFC group and 10 ± 3 (Bos indicus) and 12 ± 2 (Bos indicus‐taurus) follicles for the low AFC. The mean number of preantral follicles in the ovaries of Bos indicustaurus cows with high AFC (116 226 ± 83 156 follicles) was greater (p < 0.05) than that of Bos indicus cows (63 032 ± 58 705 follicles) with high AFC. However, there was no significant correlation between numbers of antral and preantral follicles.  相似文献   
10.
The aim of the present study was to compare the lipid profile in oocytes of indicus and 1/2 indicus × taurus cows with high and low antral follicle count (AFC)/oocyte yields. After an OPU procedure (D0), antral follicles ≥3 mm were counted by ultrasonography (D4, 19, 34, 49, 64), and cows were assigned to groups with either high AFC (≥30 follicles; indicus, NH group; 1/2 indicus × taurus, AH group) or low AFC (≤15 antral follicles; indicus, NL group; 1/2 indicus × taurus, AL group). The lipid profiles of the oocytes were determined by MALDI‐MS. For GI, GII and GIII oocytes, the indicus samples tend to cluster separately from the 1/2 indicus × taurus samples. The lipid species [PC (P‐38:5) + H]+ and/or [PC (P‐36:2) + Na]+, [PC (38:2) + H]+, [PC (38:5) + Na]+ and [TAG (60:8) + NH4]+ were more abundant in indicus (NH and NL groups) than 1/2 indicus × taurus. The higher lipid content in the indicus oocytes likely reflects differences in the rate of lipid metabolism and may contribute to oocyte competence and embryo development.  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