全文获取类型
收费全文 | 1057篇 |
免费 | 55篇 |
国内免费 | 2篇 |
专业分类
林业 | 40篇 |
农学 | 46篇 |
基础科学 | 5篇 |
158篇 | |
综合类 | 137篇 |
农作物 | 54篇 |
水产渔业 | 56篇 |
畜牧兽医 | 534篇 |
园艺 | 19篇 |
植物保护 | 65篇 |
出版年
2022年 | 5篇 |
2021年 | 18篇 |
2020年 | 23篇 |
2019年 | 24篇 |
2018年 | 19篇 |
2017年 | 26篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 51篇 |
2012年 | 46篇 |
2011年 | 46篇 |
2010年 | 41篇 |
2009年 | 21篇 |
2008年 | 43篇 |
2007年 | 46篇 |
2006年 | 48篇 |
2005年 | 50篇 |
2004年 | 46篇 |
2003年 | 44篇 |
2002年 | 60篇 |
2001年 | 27篇 |
2000年 | 28篇 |
1999年 | 24篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 16篇 |
1991年 | 23篇 |
1990年 | 19篇 |
1989年 | 9篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 9篇 |
1980年 | 5篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1974年 | 13篇 |
1972年 | 5篇 |
1969年 | 5篇 |
1967年 | 5篇 |
1943年 | 5篇 |
排序方式: 共有1114条查询结果,搜索用时 15 毫秒
101.
Whole blood re-calcification time in equine colic 总被引:3,自引:0,他引:3
Whole blood re-calcification times were evaluated as a measure of endotoxin-associated coagulopathy in horses. First, the effects of endotoxin concentration and duration of in vitro incubation of citrated whole blood with endotoxin on the whole blood re-calcification time of blood collected from healthy horses were determined. Increasing concentrations or incubation times of endotoxin accelerated the whole blood re-calcification time. This effect was attributed mainly to increased monocyte thromboplastin activity. Second, whole blood re-calcification time, a clotting profile, plasma factor VII activity and plasma endotoxin concentration on blood samples obtained from 35 equine colic patients and 10 healthy horses were determined. Compared with healthy horses, colic patients had a longer mean whole blood re-calcification and prothrombin time, lower per cent factor VII activity and higher mean fibrin degradation products concentration. Within the colic patient group, horses that did not survive had detectable endotoxin in plasma, longer whole blood re-calcification and prothrombin times, and lower plasma factor VII activity, compared with colic patients that survived. These data indicate that colic patients with endotoxaemia experience hypercoagulable states, followed by consumptive coagulopathy. Although the cause of endotoxin-associated coagulopathy is likely multi-factorial, increased expression of monocyte thromboplastin activity may be involved in the pathogenesis of coagulopathy. The whole blood recalcification time is a simple, fast and inexpensive way to detect coagulopathy during endotoxaemia and determine the prognosis for survival. 相似文献
102.
C Collatos D Allen J Chambers M Henry 《Journal of the American Veterinary Medical Association》1991,198(5):877-879
An 8-year-old Arabian stallion had signs of severe tailhead pruritus and slowly progressive loss of tail tone for 3 months. Palpation per rectum and radiography of the sacrocaudal region revealed a transverse, ventrally displaced fracture of the caudal portion of the sacrum. Surgical decompression and tail amputation resulted in complete recovery of athletic and reproductive function. Evidence of cauda equina neuritis was not seen on histologic examination of nerve roots obtained at surgery. 相似文献
103.
P S Madsen 《Nordisk veterinaermedicin》1979,31(11):449-454
Milk somatic cell counting was carried out by Fossomatic and microscopically. In unpreserved milk samples Fossomatic counts increased by up to 100% during the first 24 hours after milking. During the next 24 hours the counts increased by 5% whereafter they remained stable until at least 80 hours after milking, when the samples were stored at 5 degress C. On microscopical counting using methylene blue for staining, the results were stable from shortly after milking. In counting, attention had to be paid to the fact that within the first 24 hours a certain part of the cells would stain but faintly. After preservation with potassium bichromate the Fossomatic counts increased more rapidly. Stable results were found 5--8 hours after preservation. The final level of the Fossomatic counts was found to be app. 10% higher in preserved than in unpreserved samples. A smaller increase was found by microscopic counting. The rise of the cell counts during the first 24 hours after milking is probably due to inadequate stainability of living cells with ethidium bromide, resulting in a certain part of them being recorded by the Fossomatic. During the first day the vitality of the cells diminishes whereby they become stainable and countable. This process in hastened by potassium bichromate treatment. 相似文献
104.
J D Olsen T E Anderson J C Murphy G Madsen 《Journal of the American Veterinary Medical Association》1983,183(5):538-543
Bur buttercup (Ceratocephalus testiculatus) has not been considered to be poisonous, but the sudden death loss of 150 ewes while grazing it prompted study of the plant. It was found that bur buttercup can be highly toxic to sheep, with a lethal dose being as little as 500 g of green plant for a 45-kg sheep. Clinical signs of bur buttercup poisoning are weakness, depression, diarrhea, labored breathing, anorexia, and occasional fever. Postmortem findings include inflammation and edema of the rumen; hemorrhage in the left ventricle of the heart; congestion of the lungs, liver, and kidneys; and excessive fluid in the thoracic and abdominal cavities. 相似文献
105.
G A Henry 《Veterinary Clinics of North America: Small Animal Practice》1992,22(3):559-578
The radiographic changes observed in the development of CHD in the dog are complex and not fully understood despite years of research. Moderate to severe CHD is relatively easy to diagnose using standard radiographic views and evaluation techniques. However, early detection of mild or borderline CHD continues to be difficult to reliably detect radiographically. Efforts continue to be made to develop new views, techniques, and evaluation methods that will improve the radiographic evaluation of CHD. Until better methods are proven, the standard ventrodorsal leg extended view, evaluated by an experienced reviewer, will remain the method of choice for radiographic detection of CHD. 相似文献
106.
Eight field isolates of bovid herpesvirus type 4 (BHV-4) were examined by restriction analysis and Southern blot hybridization with respect to their relatedness to one another and to the BHV-4 prototype strain DN-599. Isolates were obtained from cattle exhibiting a range of disease states including abortion, pneumonia, enteritis, metritis, and vaginal blisters. Initial growth studies of all 9 viruses were performed and revealed that the overall rate of virus growth was slow when compared with that of other herpesviruses. Infection with each virus also resulted in the formation of large fused cells, which in addition to the slow growth rate, indicated that the isolates were of the cytomegalovirus type. Further studies to characterize and compare the various BHV-4 isolates were undertaken by obtaining cell-free virus from infected cell populations. Viral isolates were purified and used as a source of BHV-4 DNA. Purified DNA, representing each of the 8 field isolates and the prototype strain DN-599, were each cleaved with 3 restriction enzymes and were separated by agarose-gel electrophoresis, and the resultant fragment patterns were compared. In general, genomic fragments of the field isolates corresponded to those generated by cleavage of DN-599 DNA, with the exception of the abortion-associated isolate 83-3572. Additional minor differences were also seen between DN-599 DNA and DNA from the other field isolates, but the overall restriction patterns were similar. To confirm that all isolates were members of the BHV-4 type, hybridization studies were performed using DN-599.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
107.
108.
Henry R. Fell 《Pest management science》1977,8(4):377-379
The period since 1945 has been one of extraordinary development in British agriculture. A period during which the science of Crop Protection has advanced from practically nothing to where it is today—an accepted and essential part of everyday farming. The speed of these developments has put pressure on the industry and on the individual farmer. At the same time the economic climate of the 1960's has sharpened the search for efficient, low-cost production. The farmer has no choice but to use every weapon in his armoury. Safeguards against misuse of chemicals seem to be basically satisfactory up to the point of sale. There is, however, the basic point of whether the food producer has grown to be too dependent on chemical control, whilst neglecting good husbandry, which may be both cheaper and more effective. 相似文献
109.
110.