全文获取类型
收费全文 | 265篇 |
免费 | 16篇 |
专业分类
林业 | 24篇 |
农学 | 7篇 |
基础科学 | 1篇 |
31篇 | |
综合类 | 9篇 |
农作物 | 19篇 |
水产渔业 | 31篇 |
畜牧兽医 | 152篇 |
植物保护 | 7篇 |
出版年
2022年 | 3篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 18篇 |
2012年 | 14篇 |
2011年 | 17篇 |
2010年 | 7篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 17篇 |
2006年 | 20篇 |
2005年 | 6篇 |
2004年 | 17篇 |
2003年 | 4篇 |
2002年 | 9篇 |
2001年 | 16篇 |
2000年 | 11篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有281条查询结果,搜索用时 125 毫秒
81.
Binocular Dissecting Microscopic Studies on the Density of Toruli Tactile in the La Mancha Goat 总被引:1,自引:0,他引:1
Hidekazu Wakuri Michael J. Guinan Ralph L. Kitchell 《Anatomia, histologia, embryologia》1990,19(3):255-263
The Merkel cells and associated nervous terminal plates have been called toruli tactiles (TT). These structures can be ubiquitously seen on the shaved hairy skin after staining with a methylene blue solution. Four La Mancha goats of both sexes were examined for the density of TT. TT were visually located under a binocular dissecting microscopic (14x) and then the number of TT in the field was directly counted. The density of TT in different corporal areas of the body surface was estimated from the mean of several two-cm square samples of skin. The results obtained are as follows: The mean number per two-cm square on the whole body surface ranged from 10.06-11.36 in the male specimen and from 12.98-14.32 in the female specimen. The density of TT was rather high in the temporal and buccal areas, on the neck, chin and cranial breast, and on the lateral surface of the arm, thigh and leg. Density was moderate in the fronto-parieto-occipital area (female), on the loin and buttocks, in the upper costal, lower caudo-costal, xiphoid-umbilical and umbilical-pubic areas, and on the lateral surface of the forearm. TT were absent or very few in number on the nose and chin, the scrotum, caudal-pubic area of males, the udder, the vulva, and the digitorum manus et pedis. 相似文献
82.
T Kuramochi M Takeishi T Ishida K Kato M Ishida 《American journal of veterinary research》1987,48(2):186-188
A murine monoclonal antibody HLA-D.m1 produced against human Ia antigens which react with 10% to 30% of human peripheral-blood mononuclear cells was found to react with greater than 90% of feline mononuclear cells. The antigen was not expressed on granulocytes. By direct immunofluorescence, 7% to 41% of feline lymphocytes expressed surface immunoglobulins. In mixed-lymphocyte reaction, the addition of antibody HLA-D.m1 to cultures abolished proliferation. These studies indicate that most feline peripheral-blood mononuclear cells express Ia-like antigens. 相似文献
83.
Effects of oestrogen and anti-oestrogen on the cells of the endosteal surface of male Japanese quail 总被引:1,自引:0,他引:1
1. The endosteal cellular response occurring in the early stages of medullary bone formation was histologically examined in the femurs of male Japanese quail treated with oestrogen and antioestrogen. 2. The numbers of endosteal cells decreased, and preosteoblasts and osteoblasts increased, on the endosteal surface following oestrogen treatment. 3. After oestrogen and anti-oestrogen treatment the numbers of preosteoblasts and osteoblasts on the endosteal surface did not increase. However, endosteal cells slowly decreased in number and osteoclasts increased. 4. This study demonstrates that differentiation of osteoblasts is induced by oestrogen stimulation and suggests that osteoclasts occur by oestrogen inhibition on the endosteal surface. 相似文献
84.
85.
Ishida M Choi JH Hirabayashi K Matsuwaki T Suzuki M Yamanouchi K Horai R Sudo K Iwakura Y Nishihara M 《The Journal of reproduction and development》2007,53(3):499-508
In the corpus luteum of rats and mice, 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) catalyzes the conversion of progesterone to a biologically inactive metabolite, 20alpha-dihydroprogesterone (20alpha-OHP). The reduction of progesterone by 20alpha-HSD is believed to be important for functional luteolysis in these rodent species. In addition to the corpus luteum, expression of 20alpha-HSD has been demonstrated in tissues such as the placenta, endometrial epithelia, and fetal skin, although the roles it plays in the latter tissues remain to be determined. To determine the contribution of 20alpha-HSD to functional luteolysis and to the rodent reproductive system more generally, we generated a strain of mice with targeted disruption of the 20alpha-HSD gene. In the 20alpha-HSD-/- mice we obtained, which lacked the genomic region essential for catalytic reaction, neither 20alpha-HSD activity in the corpus luteum nor an increase in the serum concentrations of 20alpha-OHP during pseudopregnancy or pregnancy was detected. The durations of the estrous cycle, pseudopregnancy, and pregnancy were significantly prolonged in the 20alpha-HSD-/- mice, although the serum progesterone levels decreased to levels low enough for delivery of pups at term of pregnancy. In addition, the number of pups, especially live pups, was markedly decreased in the 20alpha-HSD-/- mice. These findings suggest that the role of 20alpha-HSD in functional luteolysis is relatively minor but that it is involved in the survival of newborn mice. 相似文献
86.
87.
88.
Katsutaka Oishi Naoki Ohkura Koji Kadota Manami Kasamatsu Kentaro Shibusawa Juzo Matsuda Kazuhiko Machida Shuichi Horie Norio Ishida 《Journal of circadian rhythms》2006,4(1):13-7
Background
Although the number of circulating immune cells is subject to high-amplitude circadian rhythms, the underlying mechanisms are not fully understood. 相似文献89.
Fucose-containing sulfated polysaccharides (FCSPs) extracted from seaweeds, especially brown macro-algae, are known to possess essential bioactive properties, notably growth inhibitory effects on tumor cells. In this work, we conducted a series of in vitro studies to examine the influence of FCSPs products from Sargassumhenslowianum C. Agardh (FSAR) and Fucus vesiculosus (FVES), respectively, on proliferation of melanoma B16 cells and to investigate the underlying apoptosis promoting mechanisms. Cell viability analysis showed that both FCSPs products, i.e., FSAR and FVES, decreased the proliferation of the melanoma cells in a dose-response fashion, with FSAR being more potent at lower dosages, and FVES being relatively more anti-proliferative than FSAR at higher dosages. Flow cytometric analysis by Annexin V staining of the melanoma cells exposed to the FCSPs products confirmed that both FSAR and FVES induced apoptosis. The FCSPs-induced apoptosis was evidenced by loss of plasma membrane asymmetry and translocation of the cell membrane phospholipids and was accompanied by the activation of caspase-3. The FCSPs bioactivity is proposed to be attributable to distinct structural features of the FCSPs, particularly the presence of sulfated galactofucans (notably in S.henslowianum) and sulfated fucans (notably in F. vesiculosus). This study thus indicates that unfractionated FCSPs may exert bioactive effects on skin cancer cells via induction of apoptosis through cascades of reactions that involve activation of caspase-3. 相似文献
90.
K. Ikeya Y. Ishida H. Ohtani S. Yamamoto & A. Watanabe 《European Journal of Soil Science》2007,58(5):1050-1061
Although condensed aromatic components are considered to be one of the major structural units of soil humic acids (HAs) and to be responsible for the dark colour of HAs, their amount and composition remain largely unknown. In ruthenium tetroxide oxidation (RTO), condensed aromatic components are detectable as their degradation products, mainly benzenepolycarboxylic acids (BPCAs). We applied this technique to soil HAs with various degrees of humification (darkening). The yields of water‐ and dichloromethane‐soluble products from HAs upon RTO after methylation ranged from 210 to 430 mg g−1 and 10–40 mg g−1, respectively. Eight kinds of BPCAs with two to six carboxyl groups, and seven kinds of BPCAs with additional side chains (tentative assignment) were obtained as methylated counterparts. The yield of each BPCA and the sum of the yields of BPCAs (12–85 mg g−1 HAs) increased with increasing degree of humification and aromatic C content. The compositions of BPCAs indicated that the degree of condensation was greater in the HAs with greater degrees of humification. The sum of the yields of aliphatic compounds ranged from 0.1 to 6.5 mg g−1, and decreased with increasing degree of humification. The C12 to C30 monocarboxylic acid methyl esters accounted for > 56% of the aliphatic compounds assigned, which may be present mainly as end alkyl groups in the HA molecules. We also obtained the methylated counterparts of C14 to C24 dicarboxylic acids; these were possibly derived from polymethylene bridges between adjacent aromatic rings. 相似文献