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   367篇
  免费   2篇
  国内免费   1篇
林业   41篇
农学   7篇
基础科学   3篇
  47篇
综合类   12篇
农作物   2篇
水产渔业   44篇
畜牧兽医   196篇
园艺   3篇
植物保护   15篇
  2020年   2篇
  2019年   1篇
  2018年   2篇
  2016年   5篇
  2014年   7篇
  2013年   25篇
  2012年   19篇
  2011年   27篇
  2010年   8篇
  2009年   18篇
  2008年   29篇
  2007年   28篇
  2006年   30篇
  2005年   28篇
  2004年   22篇
  2003年   25篇
  2002年   19篇
  2001年   18篇
  2000年   14篇
  1999年   12篇
  1998年   3篇
  1997年   1篇
  1996年   2篇
  1992年   2篇
  1991年   4篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1985年   3篇
  1984年   3篇
  1983年   1篇
  1981年   1篇
  1978年   1篇
  1966年   1篇
排序方式: 共有370条查询结果,搜索用时 15 毫秒
121.
Herpesvirus papio 2 (HVP2), which infects baboons, is much more closely related genetically and antigenically to monkey B virus (BV) than to human herpes simplex virus 1(HSV1) and other related herpes viruses. The usefulness of HVP2 as an alternative test antigen in immunoblotting assays to detect BV-antibody in macaque monkey sera was assessed. Six HVP2 proteins reacted with BV-positive sera in immunoblotting. No specific bands could be detected with BV-negative sera. These results show the usefulness of HVP2 antigen as an alternative and safer antigen than authentic BV antigen in detecting BV antibody in immunoblotting.  相似文献   
122.
Retinoids, all-trans-retinoic acid (ATRA) and 9-cis-retinoic acid (9-cis-RA), induced morphological changes and apoptosis-like cell death characterized by cell shrinkage, chromatin condensation and nuclear disintegration in three canine osteosarcoma cells, OOS, HOS and POS, at a concentration of 10(-5) M. Both retinoid receptors, RARs and RXRs, were identified in these cells. 9-cis-RA bound to both the RXRs and the RARs, whereas ATRA bound to only the RARs in these cells. Those results indicate that the induction of apoptosis in canine osteosarcoma cells may be mediated by the specific control of RARs and RXRs.  相似文献   
123.
The monoclonal antibody AM-3K, which was developed using human pulmonary macrophages as the immunogen, immunocytochemically labels most human macrophages except for blood monocytes and dendritic cell populations. AM-3K also shows cross-reactivity in some animal species. To evaluate the usefulness of AM-3K, the present study investigated the detailed distribution of AM-3K-immunopositive macrophages in normal and diseased tissues of dogs, cats, horses, cattle, pigs, and rabbits. Zamboni's solution-fixed, paraffin-embedded sections were the most available for the immunocytochemistry with AM-3K. In all animal species examined, AM-3K labeled most macrophages in splenic red pulp, lymph node sinuses and thymus, and tissue macrophages in the interstitium of various organs and sites such as the kidneys, lungs, heart, pancreas, intestines, and skin. Alveolar macrophages and perivascular microglial cells were also immunoreactive for AM-3K. Interestingly, Kupffer cells of dogs, cats, and horses were labeled for AM-3K, but those of cattle, pigs, and rabbits were not. Furthermore, in tumor tissues and inflammatory lesions such as liver fibrosis and encephalomalacia that were obtained from dogs, infiltrating macrophages were stained with AM-3K, but not all infiltrating macrophages reacted to AM-3K. In addition, only 30-50% of pulmonary and peritoneal macrophages obtained from cats and dogs were reactive for AM-3K. AM-3K did not react with blood monocytes, dendritic cell populations, and osteoclasts. These observations indicate that AM-3K specifically labels most exudate and tissue macrophages in the animal species examined. However, the expression of antigens recognized by AM-3K on macrophages may be dependent on differential maturation stages or different functions evoked by some conditions. AM-3K immunoreaction products were seen on the cytoplasmic membrane of macrophages by immunoelectron microscopy. AM-3K would be useful for detection of macrophage populations in the animal species examined here.  相似文献   
124.
中华绒螯蟹线粒体DNA 12S rRNA基因片段的序列研究   总被引:4,自引:0,他引:4  
首次进行了中华绒螯蟹(Eriocheir sinensis)线粒体DNA12SrRNA的序列分析。参考果蝇、蚤状序列对中华绒螯蟹线粒体DNA12SrRNA基因片段做了引物设计、PCR扩增及序列测定,结果得到457bp的碱基序列,其A、T、G、C含量分别为159bp(34.79%)、177bp(38.73%)、51bp(11.16%)、70bp(15.32%)、与果蝇、蚤状的相同基因片段的序列含量基  相似文献   
125.
126.
The molecular adapter Fyb/Slap regulates signaling downstream of the T cell receptor (TCR), but whether it plays a positive or negative role is controversial. We demonstrate that Fyb/Slap-deficient T cells exhibit defective proliferation and cytokine production in response to TCR stimulation. Fyb/Slap is also required in vivo for T cell-dependent immune responses. Functionally, Fyb/Slap has no apparent role in the activation of known TCR signaling pathways, F-actin polymerization, or TCR clustering. Rather, Fyb/Slap regulates TCR-induced integrin clustering and adhesion. Thus, Fyb/Slap is the first molecular adapter to be identified that couples TCR stimulation to the avidity modulation of integrins governing T cell adhesion.  相似文献   
127.
128.
It is essential to analyze chemical properties including the amount of various materials and the soil colloid characteristics in forest soils to forecast wood production and the distribution of and variations in the environmental functions of forest soils, such as conservation of stream water and carbon sequestration. Approximately 70% of the forest soils in Japan consists of Brown Forest Soils (BFS), which are considered to be typical zonal soils under the humid-temperate and warm-temperate regime of Japan. BFS were subclassifled into several groups according to the soil moisture environment along the slope and morphological properties. However, even the same type of soil may display different properties depending on the climatic conditions, parent materials and vegetation types. In the present study, the variations in the carbon content, nitrogen content, cation exchange capacity and some properties depending on the parent materials, were clarified by using 34 sola of BFS, and 3 sola of black soils (BLS) for comparison, which were distributed in the submontane zone of the Kanto and Chubu districts in central Japan under the same climatic conditions. We observed differences in the pH, cation exchange capacity, base saturation and clay content among BFS samples derived from various parent materials. The BFS derived from volcanic ash contained obviously larger amounts of carbon and nitrogen than the BFS derived from other parent materials. However, the BFS derived from volcanic ash differed from the BLS derived from volcanic ash in the vertical distribution pattern of carbon and nitrogen. Thus, even in the submontane zone of the Kanto and Chubu districts, the chemical properties of BFS varied considerably with the parent materials. It was concluded that the classification of BFS by the parent materials was useful for evaluating the ability of the BFS, that cover 70% of the forests in Japan, to store various materials.  相似文献   
129.
A unique lipoprotein profile was found in the plasma of cultured Japanese eel,Anguilla japonica which accumulated more lipid in its muscle than in its liver. The plasma lipoprotein level of Japanese eels was in excess of 54 mg ml1, a concentration considered to be hyperlipoproteinemic in relation to other teleosts. The plasma lipoproteins consisted of very low density lipoprotein (VLDL, density (d)<1.006 g ml1) low density lipoprotein (LDL, 1.0061), high density lipoprotein 2 (HDL2, 1.0851), and HDL3 (1.1001). VLDL, but not HDL, was the main component in the plasma of Japanese eels, unlike most teleosts where HDL is the main component. An additional lipoprotein, vitellogenin (1.2101), was induced by the injection of estradiol-17ß (E2), but VLDL was the main plasma component even in the E2-treated eels. VLDL was a triacylglycerol (TG)-rich lipoprotein and possessed two apolipoprotein (apo) B-like proteins of molecular weights (Mr) 260K and 230K as main components.LDL, HDL2, and HDL3 were revealed to consist of heterogeneous components by a density gradient ultracentrifugation. LDL was separated into three subclasses of LDL1 (1.0301), LDL2 (1.0431), and LDL3 (1.0671). LDL1 with apo B-like protein of Mr 230K was a TG-rich lipoprotein, while both LDL2 and LDL3 were cholesterol ester-rich lipoproteins with apo A-I-and A-II-like proteins of Mr 25K and 14K. The particle sizes of HDL2 and HDL3 subclasses differed, although all of HDL2 and HDL3 subclasses possessed apo A-I-and A-II-like proteins of Mr 25K and 14K as main components. To our knowledge, this is the first report of detailed plasma lipoprotein profile in Japanese eels.Corresponding author: till August 18, 1996 and after April 19, 1997: at the above address. From August 19, 1996 till April 18. 1997: c/o Dr. N.H. Haunerland, Department of Biological Sciences. Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.  相似文献   
130.
To elucidate the effects of an exogenous calcitriol (1,25-dihydroxyvitamin D3) on plasma bone markers, the formation item osteocalcin (OC), undercarboxylated OC (ucOC) and bone-specific alkaline phosphatase (BALP), and the resorption parameter tartrate-resistant acid phosphatase isoform 5b (TRAP5b) and hydroxyproline (HYP) were measured in conjunction with plasma calcitriol and calcium (Ca) concentrations in dairy cows receiving calcitriol or its vehicle according to a 2 × 2 crossover design. Calcitriol (0.5 μg/kg, i.m.) increased significantly its plasma level during 6 h to day 2 and plasma Ca concentration during 12 h to day 7 compared to the vehicle. Also, plasma OC and ucOC started to rise from day 3 and 1, respectively, and remained elevated until day 7. No change in plasma BALP, TRAP5b or HYP associated with calcitriol treatment was noted. These results demonstrate that exogenous calcitriol stimulates osteoblasts to biosynthesise OC, a determinant of the bone formation in cows.  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