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   436篇
  免费   44篇
林业   17篇
农学   10篇
基础科学   1篇
  44篇
综合类   80篇
农作物   20篇
水产渔业   14篇
畜牧兽医   250篇
园艺   11篇
植物保护   33篇
  2022年   6篇
  2020年   11篇
  2019年   8篇
  2018年   7篇
  2017年   8篇
  2016年   7篇
  2015年   6篇
  2014年   5篇
  2013年   12篇
  2012年   14篇
  2011年   20篇
  2010年   17篇
  2009年   12篇
  2008年   18篇
  2007年   10篇
  2006年   15篇
  2005年   18篇
  2004年   13篇
  2003年   14篇
  2002年   14篇
  2001年   9篇
  2000年   8篇
  1999年   5篇
  1998年   4篇
  1995年   4篇
  1993年   6篇
  1992年   10篇
  1991年   14篇
  1990年   11篇
  1989年   6篇
  1988年   9篇
  1987年   7篇
  1986年   9篇
  1985年   9篇
  1984年   6篇
  1983年   9篇
  1981年   7篇
  1980年   7篇
  1979年   5篇
  1978年   7篇
  1977年   5篇
  1976年   4篇
  1975年   6篇
  1973年   8篇
  1972年   5篇
  1971年   10篇
  1970年   6篇
  1969年   4篇
  1967年   6篇
  1886年   4篇
排序方式: 共有480条查询结果,搜索用时 0 毫秒
51.
The morphological and biochemical consequences of transplanting affected bone marrow from donor BALB/c mice with a lysosomal storage disorder (BALB/c LSD) into normal recipient mice were studied. Bone marrow was removed from normal BALB/c and BALB/c LSD mice and transfused into normal BALB/c recipient mice four hours after the mice received 850 rads of irradiation. Tissues of the recipient mice were examined 240 days later. This study revealed that the defective cells that constituted the visceral lesions of BALB/c LSD could be transplanted to normal BALB/c mice by the use of bone marrow from affected BALB/c LSD homozygote; that the defective cells of BALB/c LSD proliferated and disseminated throughout the mononuclear phagocytic system of the recipient; that there were increases in cholesterol, sphingolipids, and cystine with decreases in sphingomyelinase and glucocerebrosidase activity in tissues of the recipients; and that the recipients survived substantially longer than BALB/c LSD homozygotes and their lifespan was compromised mainly by the secondary effects of irradiation. These lesions, although not as extensive as in homozygous BALB/c LSD, paralleled the lesions which develop in BALB/c LSD. Since the recipient mice were not compromised by the short life span (70 days) of the BALB/c LSD mice, they may be used to study the long-term chronic effects of these metabolic lesions.  相似文献   
52.
Twelve horses with traumatic arthritis were treated with intraarticular injection of hyaluronic acid mixed with cortisone and the results compared with 6 horses treated only with cortisone. There was a significantly better improvement in the group injected with a mixture of hyaluronic acid and cortisone. Further studies have given the same results in traumatic arthritis in horses if hyaluronic acid alone is injected.After injection of hyaluronic acid a large number of granulated monocytes appeared in the synovial fluid, but no inflammatory signs were observed. It is possible that this macrophage invasion is instrumental in producing improvement in the condition of the joint. The injected hyaluronic acid may also adhere to the surface of articular cartilage producing an “clastic cushion” protecting the cartilage surface.Experimental mechanical damage was also inflicted on the surface of articular cartilage in dogs and monkeys, and smoother healing was achieved if hyaluronic acid was injected into the joints after the damage.Injections of hyaluronic acid seem to be of value in treating traumatic arthritis or similar conditions.  相似文献   
53.
54.
Piroplasmosis, a disease endemic to most tropical and subtropical areas, appears to be spreading to more temperate zones. This article gives a review of equine piroplasmosis and describes an acute case of infection with Babesia caballi in a Dutch Standard bred foal after a short stay at a stud in Normandy (France). A 3-month-old stallion foal was presented with lethargy, fever of 41 degrees C, and pale mucosal membranes. Haematology revealed a low packed cell volume (14 l/l) leucytosis (25 G/l) and a high blood urea nitrogen concentration (20.1mmol/l). Infection with B. caballi was diagnosed on the basis of Giemsa staining blood smears and was confirmed by polymerase chain reaction in combination with RLB. Treatment with imidocarb dipropionate and a blood transfusion resolved the haemolytic crisis.  相似文献   
55.
The enzyme-linked immunosorbent assay (ELISA) was evaluated for use in the quantitative measurement of bovine immunoglobulin IgG1 and IgG2 antibodies. A method for standardization was devised in which IgG1 or IgG2 was directly adsorbed to polystyrene tubes and the actual degree of binding was calculated by using different input amounts of 125I-labeled IgG1 or IgG2. Values for quantity of IgG1 antibodies to human serum albumin were only slightly higher when measured by the ELISA than when measured by quantitative precipitation although the value measured by the ELISA for IgG2 antibodies was twice that determined by quantitative precipitation. This discrepancy could result from conjugate cross reactivity, differences in affinity between antibodies of the 2 subclasses, or the occurrence of IgG2 nonprecipitating antibodies. The danger of overlooking subclass anti-globulin cross reactivity because of the failure to detect it by immunoprecipitation, also is illustrated. In addition, only enzyme-antibody conjugates prepared with specifically purified antibodies were effective, and reproducibility of individual data points required that 4 replicate determinations be performed. Advantages, pitfalls, and limitations of the ELISA are discussed.  相似文献   
56.
57.
During the 2 h following the injection of chickens (aged nine to 11 weeks) with endotoxin isolated from a pathogenic strain of Escherichia coli (O78) there was a transient rise in the activity of acid phosphatase, aryl sulphatase and beta-glucuronidase in the plasma, suggesting increased release of these enzymes from lysosomes. This was followed by a fall in their activity which may have been due largely to stabilisation of the lysosomal membrane brought about by increased secretion of adrenocortical hormones and/or accelerated removal of the enzymes from circulation by the reticuloendothelial system.  相似文献   
58.
Rectal bleeding in a 7-month-old 13-kg sexually intact female mixed-breed dog was determined to be associated with vascular ectasia of the small intestine, descending colon, rectum, and anus. Microscopically, the telangiectasia was associated with lymphangiectasia and focal ulceration. Surgical intervention resulted in incomplete resection of the lesion and only temporary amelioration of clinical signs. The dog's age was compatible with a congenital origin for the defect, but an acquired cause could not be excluded.  相似文献   
59.
A total of 567 young pigs entering one of the national testing stations were tested for sensitivity to halothane between October 1976 and May 1978. They included 443 Landrace, 76 Large White and 48 Irish Welsh. The average weight at testing was 25.6 kg. A total of 24 pigs reacted positively to the test, 21 (4.6%) of the Landrace and 3 (6.3%) of the Irish Welsh. No reactors were found in the Large White breed.Meat quality estimates in the form of the pH in the longissimus dorsi muscle 45 min post-mortem (pH1) were recorded on the 324 slaughtered pigs. Reactor pigs (ten) had significantly lower values than non-reactors, indicating a greater tendency to develop quality problems such as pale, soft, exudative (PSE) meat. There was an indication that reactor pigs might have slightly reduced daily gains and lower backfat thickness.  相似文献   
60.
Umbilical hernias are common in foals. This article provides a review of the literature and presents a case of an 1.5-year-old Friesian mare with an incarcerated umbilical hernia. After reposition of the incarcerated intestine (with a lot of effort), the practising veterinarian referred the mare to the Department of Equine Sciences. Preperforative peritonitis was diagnosed, presumed to be caused by necrotic bowel. After laparotomy, this tentative diagnosis was confirmed. The necrotic part of the small intestine was resected and intensive medical treatment was started. Initially, the mare recovered well, but seven days after surgery her general condition deteriorated and she had to be euthanized. At necropsy, impaction of the stomach and rupture of the stomach wall were found. The impaction was probably a result of the generalized peritonitis.  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