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排序方式: 共有1604条查询结果,搜索用时 31 毫秒
31.
毛细管水解及反相高效液相色谱分析蛋白质的氨基酸组成陈平,梁宋平(湖南师范大学生物研究所,长沙410006)氨基酸组成的分析是阐明蛋白质和多肽化学特性的基础,在蛋白质与多肽的氨基酸组成分析中,常采用对水解管反复充氮并抽真空的方法使蛋白质和多肽在隔绝氧气... 相似文献
32.
Summary The monoclonal antibody (MAb) JIM5, marking acidic pectins, was used to localize ultrastructurally pectin molecules in the pollen tube wall ofNicotiana tabacum. Longitudinal sections of LR-White embedded pollen tubes were exposed to antibody treatment; accumulations of pectins were identified by counting the density of the gold particles representing the pectin epitopes along the pollen tube wall. Significant accumulations of gold grains were marked and the distances between them were measured. In many pollen tubes a more or less regular distribution of the accumulations was observed along the tube indicating a periodical deposition of pectin. The distances between the accumulations were 4–6 m. Most of the label was found in the inner part of the outer layer of the bilayered cell wall. These findings correspond to and confirm the earlier observation by our group reporting ring-shaped periodical deposits in pollen tubes after immunofluorescence labelling with the MAb JIM5 under the confocal laser scanning microscope.Abbreviations Ab
antibody
- MAb
monoclonal antibody 相似文献
33.
Effects of heavy metals on pollen tube growth and ultrastructure 总被引:3,自引:0,他引:3
Summary The influence of different concentrations of the heavy metals cadmium (Cd2+), cobalt (Co2+), copper (Cu2+), iron (Fe2+ and Fe3+), mercury (Hg2+), manganese (Mn2+), and zinc (Zn2+), plus aluminium (Al3+) (a toxic metal in polluted areas), on pollen germination and tube growth ofLilium longiflorum was investigated using light microscopy. Effects could be observed with 3 M and 100 M of heavy metal, added as chloride salts to the medium. Cd2+, Cu2+, and Hg2+, showed the greatest toxicity, whereas germination and growth rate was less affected by Mn2+. Affected tubes showed swelling of the tip region. Tubes treated with Cd2+, Co2+, Fe2+, Fe3+, Hg2+, and Mn2+ were also prepared for ultrastructural studies. In all cases, the main effect was abnormal cell wall organization, mostly at the tip, where round, fibrillar aggregates, the shape and size of secretory Golgi vesicles were formed. They built up a loose network which could be up to 10 m thick compared to untreated tubes where the cell wall was composed of thin layers of long fibrils and about 100 nm thick. Cd2+ was the only metal which produced effects at the intracellular level: organelle distribution within the tip region appeared disorganized. A general mechanism of heavy metal action on pollen tube growth is discussed. 相似文献
34.
A. Chandran 《Hydrobiologia》1995,304(3):169-174
The structure and musculature of the mouth tube of the lernaeopodidIsobranchia appendiculata Heegaard is described in detail. Situated on the median eminence, the mouth tube appears to be lodged inside a median longitudinal
groove on the ventral wall of the cephalothorax. The components of the mouth tube, the labrum and the labium are loosely held
together along their lateral edges. The thin, transparent walls of both the labrum and the labium are reinforced by chitinous
rods. The musculature of the mouth tube consists of two pairs ofretractores oris, four pairs ofcompressores labri and two pairs oflevatores labii. The mandibles are operated by a pair of antagonistic muscles, theroto adductor mandibulae androto abductor mandibulae. Like other lernaeopodids,I. appendiculata resorts to a browsing type of feeding. 相似文献
35.
M. G. M. Van Creij D. M. F. J. Kerckhoffs J. M. Van Tuyl 《Sexual plant reproduction》1997,10(2):116-123
Pollen tube growth in the pistil and pollen tube penetration of ovules have both been studied in crosses between cultivars
from Tulipa gesneriana L. and 12 tulip species from all eight sections of the genus Tulipa to identify pre-fertilization barriers. Depending on the cross, pollen tubes grew as far as the stigma or the style or continued
growing down into the ovary. Pollen tubes penetrated none or only a few percent of the ovules of some crosses, despite the
presence of many pollen tubes in the ovary. In other crosses, from which no or only a few hybrids have been obtained after
seed maturation on the plant, pollen tube penetration was found in up to 79% of the ovules. Apparently, various kinds of barriers
preventing fertilization or normal embryogenesis occur in interspecific tulip crosses.
Received: 26 July 1996 / Revision accepted: 31 January 1997 相似文献
36.
鹅掌楸属植物引导组织和花粉管生长 总被引:9,自引:0,他引:9
应用光学显微镜和常规石蜡切片技术研究了鹅掌楸属(LiriodendronL.)两种植物雌蕊引导组织的分布和个体发育,引导组织是由心皮边缘或内表面的表皮细胞层或亚细胞层发育形成,是由一层细胞组成的连续层,覆盖干柱头、花柱道和珠柄的表面,引导组织的细胞形态学因其所在部位不同而有差异。在电境水平上研究了柱头和花柱引导组织的超微结构,引导组织细胞是分泌型的传递细胞,其分泌面发育了明显的壁内突,细胞质中富含内质网、多聚核糖体、各种小泡、高尔基体和线粒体,大液泡通常远离分泌面。文中还探讨了花粉管生长后引导组织的变化。 相似文献
37.
Pollen of Lilium longiflorum Thunb. was germinated for 12 h in growth medium containing 1·10-4 M chlorotetracycline (CTC), or growing tubes were treated with 1·10-4 M CTC for up to 2 h. These treatments have drastic effects: In the CTC-containing medium, out-growing tubes form only short tubes. Irregular wall thickenings are visible. Thirty minutes CTC-treatment cause growing tubes to bend and grow back toward the grain. Electron micrographs of CTC-treated tubes show that CTC affects the organelle distribution: The polar zonation of organelles is disturbed. Vesicle-and endoplasmic reticulum-accumulations are found in the wrong places, together with extensive wall thickenings and a very irregular plasma membrane. The structural details of most cell organelles look normal after CTC treatment, but the mitochondria possess unusual cristae, and microtubules are absent. The disoriented growth is interpreted as an effect of the ability of CTC to chelate intracellular calcium ions, to bind them to membranes, and thus to disturb the dynamics of the delicate Ca2+-equilibria thought to regulate oriented exocytosis.Abbreviations CTC
chlorotetracycline
- ER
endoplasmic reticulum 相似文献
38.
No differences have been observed in vivo between Lycopersicum peruvianum compatible and incompatible pollen during activation and pollen tube emission and organization, that is until 4 h and 30 min after pollination. During pollen activation the main events are the setting free of rough endoplasmic reticulum (RER) cisterns which were stacked in the mature pollen, the increase in the number of polysomes, and a great activity of the dictyosomes. Immediately after germination of the vegetative nucleus and the generative cell move into the tube, the generative cell diviting to form the male gametes; the tube then becomes organized in four zones. This series of changes is similar to what has already been observed in vitro except that in vitro the generative cell remains undivided and the whole process from seeding to tube organization takes 3 h instead of 4 h and 30 min after pollination, as it does in vivo. Our findings are compatible with the main models of the tube inhibition mechanism proposed till now.Abbreviations RER
rough endoplasmic reticulum
- GC
generative cell
- VN
vegetative nucleus
- GP
germinative pore
Research performed under C.N.R. (Italian National Research Council) program Biology of Reproduction 相似文献
39.
Progesterone receptors were determined in the cytosol from the ampulla, ampullaryisthmic junction and isthmus of rabbit fallopian
tube and uterus of estrus and pregnant rabbits. The receptor levels when compared among its various anatomical segments, were
the same in ampulla, isthums and uterus but maximum in ampullary-isthmic junction. Significant differences were observed in
mated animals at 14, 24, 34, 48, 70 and 144 h after coitus. The receptor concentrations in portions of the fallopian tube
showed no significant change between 14 and 24 h after coitus, except for a decrease in ampullary-isthmic junction at 24 h.
At 34 h the concentration of receptor further decreased in all parts of the tube. At 48 and 70 h after coitus, receptor concentrations
decreased gradually in ampulla and ampullary-isthmic junction, while isthmus showed a gradual increase. At 144 h, the receptor
concentration showed no further change in ampulla and ampullary-isthmic junction; however, isthmus showed a decline. The uterine
receptor concentration declined steadily from estrus till 70 h after coitus, however, it was increased at 144 h. The dissociation
constant (Kd) of cytosol receptor in all the tissues at estrus and during early pregnancy was found similar. The implications of these
changes in relation to the normal ovum transport have been correlated in this paper. 相似文献
40.
N. K. Paul 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1978,52(5):233-237
Summary The relative ability of cross- and self-pollen to achieve fertilisation in Brassica was studied by making double pollinations using cross-pollen carrying a dominant seedling marker gene. With simultaneous self- and crosspollination 12–40% self-seed was set, but when cross-pollen was applied to the stigma four hours before self-pollen, only 2–4% self-seed was obtained. In two plants to which cross-pollen was applied at various time intervals after self-pollen there was a tendency for the percentage of self-seed to increase as the time interval increased. In a third plant this trend was not apparent, probably because of a greater degree of self-incompatibility. The competitive advantage of the first pollen to arrive on the stigma is discussed in relation to the strength of the self-incompatibility and the sib problem in F1 hybrid brassicas. 相似文献