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101.
Seed protein electrophoresis of four chromosomes races ofFestuca arundinacea, F. mairei and their progenitors showed variation in banding patterns. High protein similarities betweenF. arundinacea, F. mairei, F. scariosa, andF. pratensis indicate close phylogenetic relationships of these species. The ancestry ofF. arundinacea cytotypes could be narrowed to three diploid species:F. scariosa, F. pratensis, andF. rubra or to their close relatives. 相似文献
102.
The incidental catch of northern sea lions ( Eumetopias jubatus ) in the walleye pollock ( Theragra chalcogramma ) joint-venture fishery in Shelikof Strait, Alaska, was studied during 1982–1984 to assess the nature and magnitude of the catch. Data were obtained by placing U.S. observers on foreign processing vessels. Dead sea lions recovered from trawl nets were counted, sexed and measured, teeth were removed for age determination by dental laminae; and stomach contents were analyzed. Although the fishery has continued to expand both in number of boats and estimated total catch (74,136 metric tons [t] in 1982 to 171,539 t in 1984), the estimated incidental catch of northern sea lions has declined (ranging from 958 to 1,436 in 1982, 216 to 324 in 1983 and 237 to 355 in 1984). Of the sea lions processed, 73 percent were caught between 2000 and 0500 h, probably during net retrieval. Most caught sea lions were females ranging in age from 1–25 yr with a mean age of 6.43 yr; 79 percent of the females were sexually mature and probably part of the reproducing population. Males had a mean age of 4.8 yr and only 12 percent were old enough to obtain and defend territories. Analysis of stomach contents showed that the sea lions consumed pollock the same size as that taken by the commercial fishery. The impact of the incidental catch on the Gulf of Alaska sea lion population is unknown. 相似文献
103.
R. BREGMAN F. BOUMAN 《Botanical journal of the Linnean Society. Linnean Society of London》1983,86(4):357-374
The mode of germination of representatives of 89 genera of the Cactaceae, 4 genera of Portulacaceae and 1 genus of Phytolaccaceae was studied. Most of the species of the Cactaceae germinate by means of a seed lid (operculum). In the Cactaceae studied 11 kinds of germination could be distinguished, 3 of which were with, and 8 without, operculum formation.
Opercula are restricted in their occurrence to the subfamilies Cactoideae (Cereoideae) and Pereskioideae and are not found in the subfamily Opuntioideae. Within the subfamily Cactoideae operculum formation was found to occur in all tribes and in all investigated subtribes. Opercula were also found in two genera of the related family of the Portulacaceae. In the Phytolaccaceae no operculum formation was observed. 相似文献
Opercula are restricted in their occurrence to the subfamilies Cactoideae (Cereoideae) and Pereskioideae and are not found in the subfamily Opuntioideae. Within the subfamily Cactoideae operculum formation was found to occur in all tribes and in all investigated subtribes. Opercula were also found in two genera of the related family of the Portulacaceae. In the Phytolaccaceae no operculum formation was observed. 相似文献
104.
A hitherto unknown hydroxy acid has been isolated from Blepharis sindica seed oil has been characterized as 9-hydroxydodecanoic acid by IR, NMR and mass spectral studies. The structure of this acid was further supported by its chemical transformations. 相似文献
105.
The fat of the seeds from the West African tree Pycnanthus kombo contains ca 20% of a hitherto undescribed compound. This compound was identified as 16(2′,5′-dihydroxy-3′-methylphenyl)-2,6,10,14-tetramethyl-2,6,10,14-hexadecatetraenoic acid, for which the name kombic acid is proposed. 相似文献
106.
The influence of kairomones on the numerical response of the parasitoidTrioxys indicus against its hostAphis craccivora at its varying density was studied. The kairomones (applied as aqueous extract of the host) significantly enhanced the rate
of parasitisation and multiplication and the area of discovery of the parasitoid and also the K-values of mortality of the
host at all parasitoid densities introduced (1, 2, 4, 8, 12 and 16 parasitoids) into troughs having about 200 hosts. The sex-ratio
of F1 offspring decreased at lower parasitoid densities and remained more or less unchanged at higher parasitoid densities after
the application of kairomones. The present findings indicate that if kairomones are applied properly, the number of hosts
destroyed by a stimulated parasitoid will be about 200, twice the number reported earlier, thus fewer parasitoids will be
needed to regulate an estimated population of the hosts.
相似文献
107.
本文采用反相高效液相色谱(reversedphase high-performance liquid chromatography,RP-HPLC)技术分析了中国种植的24个不同大麦品种的种子醇溶贮藏蛋白质。首先,根据所获得的色谱图的相似性可以将供试品种分成10组,每组各有自己的共同特征色谱峰;其次,再依据各组内不同品种间色谱图的定性或定量上的差异可以将它们分别区别和鉴定;这表明大麦种子醇溶贮藏蛋白质的异质性较强,其组成随基因型的不同而有所变异。因此,应用RP-HPLC技术分析大麦种子醇溶贮藏蛋白质可以准确、快速地对大麦品种进行鉴定。 相似文献
108.
Shiro Tsuyuzaki 《Ecological Research》1989,4(2):167-173
In 1987, a study on buried seed populations was conducted in the crater basin of Mt. Usu, a volcano located in northern Japan,
where the vegetation had beeen almost completely destroyed by eruptions in 1977 and 1978. The former vegetation had consisted
of grassland and broad-leaved forest. In the areas formerly occupied by this grassland and forest, 2128.0 and 1985.3 seeds
per square meter, respectively, were extracted from 12 blocks of the former topsoil using a floattion method. This revealed
that many seeds were still viable even after ten years of burial under thick volcanic deposits. The seeds were distributed
more in sandy soil than in rocky soil of the former topsoil. Twenty-five species, most of which favored grassland, were detected
in both the former grassland and forest. From comparison of α-and β-diversities between the grassland and forest, the structure
of the buried seed population was considered likely to have been more diverse in the forest than in the grassland. The determinants
of composition of the buried seed populations were discussed with reference to the former vegetation and soil characteristics. 相似文献
109.
Yaushisa Henmi 《Ecological Research》1989,4(3):261-269
Mortality of eggs during incubation was estimated for three ocypodid crabs,Scopimera globosa, Ilyoplax pusillus andMacrophthalmus japonicus, and the influence of incubation sites was discussed. These crabs all lived in isolated burrows and fed on sediments during
day time low tide.S. globosa andI. pusillus inhabited the upper intertidal sandflats, whereasM. japonicus inhabited the lower intertidal mudflats. Females of bothS. globosa andI. pusillus remained in their plugged burrows without feeding throughout incubation and the mortality of eggs was low despite large broods
relative to body size. On the other hand, females ofM. japonicus fed actively on surface mud during incubation and the mortality of eggs was high despiite small broods relative to body size.
InS. globosa andI. pusillus, the ovaries of ovigerous females were small until egg-hatching, whereas inM. japonicus, the ovaries grew rapidly during incubation and females were able to produce consecutive broods. I conclude that incubation
of eggs in burrows may be advantageous in species which inhabit the upper interidal sandflats, even though the crabs cannot
forage during incubation, since otherwise their eggs would be exposed to strong heat stress and desication during the summer.
Furthermore, such species may produce few large broods because of less frequent interruption of feeding than that associated
with production of many small broods. 相似文献
110.
Shiro Tsuyuzaki 《Journal of plant research》1989,102(4):511-520
Soon after the 1977–78 eruptions of the volcano Usu, there were created many gullies in which former topsoil, i.e., well-developed
soil accumulated before the eruptions, was eroded in the crater basin, whereas the outside of the gully was covered with thick
volcanic deposits. The short-dispersal-seed plants were the most abundant in the inside of gully where the former topsoil
was exposed, however, they have not immigrated from external environments. The germination tests of the seeds extracted from
the former topsoil demonstrated that viable seeds were buried at 1683.3/m2 for 9 years after the eruptions. At least, 12 herbaceous species, e.g.,Rumex obtusifolius, Geum macrophyllum var.sachalinense andPoa annua, were derived from the buried seeds in the former topsoil. Their contribution to revegetation was estimated to be 40.0% in
the inside of gully where the former topsoil was exposed in 1983, suggesting that buried seeds are one of the most important
seed source for revegetation even in the case of a volcano which produced pumice and ash by eruption. 相似文献