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991.
Based on more than 4000 km 2D seismic data and seismic stratigraphic analysis, we discussed the extent and formation mechanism of the Qiongdongnan deep sea channel. The Qiongdongnan deep sea channel is a large incised channel which extends from the east boundary of the Yinggehai Basin, through the whole Qiongdongnan and the Xisha trough, and terminates in the western part of the northwest subbasin of South China Sea. It is more than 570 km long and 4–8 km wide. The chaotic (or continuous) middle (or high) a... 相似文献
992.
To reconstruct the formation and evolution process of the warm current system within the East China Sea (ECS) and the Yellow
Sea (YS) since the last deglaciation, the paleoceangraphic records in core DGKS9603, core CSH1 and core YSDP102, which were
retrieved from the mainstream of the Kuroshio Current (KC), the edge of the modern Tsushima Warm Current (TWC) and muddy region
under cold waters accreted with the Yellow Sea Warm Current (YSWC) respectively, were synthetically analyzed. The results
indicate that the formation and evolution of the modern warm current system in the ECS and the YS has been accompanied by
the development of the KC and impulse rising of the sea level since the last deglaciation. The influence of the KC on the
Okinawa Trough had enhanced since 16 cal kyr BP, and synchronously the modern TWC began to develop with the rising of sea
level and finally formed at about 8.5 cal kyr BP. The KC had experienced two weakening process during the Heinrich event 1
and the Younger Drays event from 16 to 8.5 cal kyr BP. The period of 7–6 cal kyr BP was the strongest stage of the KC and
the TWC since the last deglaciation. The YSWC has appeared at about 6.4 cal kyr BP. Thus, the warm current system of the ECS
and the YS has ultimately formed. The weakness of the KC, indicated by the occurrence of Pulleniatina minimum event (PME) during the period from 5.3 to 2.8 cal kyr BP, caused the main stream of the TWC to shift eastward to
the Pacific Ocean around about 3 cal kyr BP. The process resulted in the intruding of continent shelf cold water mass with
rich nutrients. Synchronously, the strength of the YSWC was relatively weak and the related cold water body was active at
the early-mid stage of its appearance against the PME background, which resulted in the quick formation of muddy deposit system
in the southeastern YS. The strength of the warm current system in the ECS and the YS has enhanced evidently, and approached
to the modern condition gradually since 3 cal kyr BP.
Supported by the National Natural Science Foundation of China (Nos. 90411014 and 40506015), the National major Fundamental
Research and Development Project (No. 2007CB815903) and the CAS Pilot Project of the National Knowledge Innovation Program
(No. KZCFX3-SW-233) 相似文献
993.
The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual
reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar
to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population
increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species.
Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.
Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-208), National Natural Science
Foundation of China (No. 40821004, U0733006) and National Basic Research Program of China (973 Program, No. 2001CB409700) 相似文献
994.
A full length amphioxus cDNA, encoding a novel phosducin-like protein (Amphi-PhLP), was identified for the first time from the gut cDNA library of Branchiostoma belcheri. It is comprised of 1 550 bp and an open reading frame (ORF) of 241 amino acids, with a predicted molecular mass of approximately
28 kDa. In situ hybridization histochemistry revealed a tissue-specific expression pattern of Amphi-PhLP with the high levels in the ovary, and at a lower level in the hind gut and testis, hepatic caecum, gill, endostyle,
and epipharyngeal groove, while it was absent in the muscle, neural tube and notochord. In the Chinese Hamster Ovary (CHO)
cells transfected with the expression plasmid pEGFP-N1/Amphi-PhLP, the fusion protein was targeted in the cytoplasm of CHO cells, suggesting that Amphi-PhLP is a cytosolic protein. This work may provide a framework for further understanding of the physiological function of
Amphi-PhLP in B. belcheri.
Supported by the Pilot Projects of Knowledge Innovation Project of Chinese Academy of Sciences (No. KZCX2-YW-211-03 and MGE2008KG06) 相似文献
995.
By combining Argos drifter buoys and TOPEX/POSEIDON altimeter data, the time series of sea-surface velocity fields in the
Kuroshio Current (KC) and adjacent regions are established. And the variability of the KC from the Luzon Strait to the Tokara
Strait is studied based on the velocity fields. The results show that the dominant variability period varies in different
segments of the KC: The primary period near the Luzon Strait and to the east of Taiwan Island is the intra-seasonal time scale;
the KC on the continental shelf of the ECS is the steadiest segment without obvious periodicity, while the Tokara Strait shows
the period of seasonal variability. The diverse periods are caused by the Rossby waves propagating from the interior ocean,
with adjustments in topography of island chain and local wind stress.
Supported by the National Basic Research Program of China (973 Program, Nos. 2007CB411804, 2005CB422303), the NSFC (No. 40706006),
the Key Project of International Science and Technology Cooperation Program of China (No. 2006DFB21250) and the “111 Project”
(B07036), the Program for New Century Excellent Talents in University (NECT-07-0781) 相似文献
996.
Immunostimulants may improve disease resistance of aquaculture animals by promoting the nonspecific immunity response of the
organisms. Five types of saccharides, including chitosan, yeast polysaccharide, burdock oligosaccharide, seaweed polysaccharide
and lentinus edodes polysaccharide, were screened for potential use as immunostimulants by using spectrophotometry. The saccharides
were injected into Apostichopus japonicus, a sea cucumber, and the lysozyme and superoxide dismutase (SOD) activities of the coelomic fluid and epidermal slime were
monitored in six consecutive days. The results show that the lysozyme activity of the animal’s coelomic fluid was significantly
stimulated on day 2, day 4 and day 6 after the injection of the saccharides (P<0.05). The effects of chitosan and yeast polysaccharide were the most notable. The lysozyme activity of the epidermal slime
was significantly increased by chitosana, yeast polysaccharide, seaweed polysaccharide, and burdock oligosaccharide on day
1 and day 2 after the injection (P<0.05). The SOD activity of the coelomic fluid was significantly promoted by the saccharides on day 2 and day 4 post-injection
(P<0.05), while the SOD activity of the epidermal slime increased on day 2. These findings indicate that chitosan and yeast
polysaccharide are the most effective immunostimulants and potential healthy anti-disease feedstuff for A. japonicus.
Supported by the National Key Technology Research and Development Program (863 Program, No. 2006BAD09A06) and the Special
Fund of Chinese Central Government for Basic Scientific Research Operations in Commonweal Research Institutes (No. 02-2007B03) 相似文献
997.
The Mekong supports one of the richest inland fisheries in the world, with many of the fish migrating long distance to spawn.
Little is known about the fisheries and migration strategies of the Upper Mekong whilst it is supposed that many fish species
move between the Lower and Upper Mekong. Most likely, natural fish migration in the river has been altered by dam construction
across the mainstream of the Upper Mekong. In this paper, the interconnectivity of fish species between different sections
of the Mekong and negative impacts of dams on migratory fish are studied. Of the 162 fish species in the Upper Mekong and
the 869 species in the Lower Mekong, 61 species are common. Results show that there is no significant difference at order
level between the UM and LM. Similarity coefficients are used to evaluate interconnectivity at species, genus and family levels
among four different sections of the Upper Mekong with each other and with the Lower Mekong as a whole. The highest similarity
is found between the middle and lower reach of the Upper Mekong at species and genus levels and the middle and upper reach
at family level. Of the eight cascade dams, Mengsong Dam in planning is considered as the biggest threat to migratory fish
from the Lower Mekong and should be particularly concerned.
Supported by National Natural Science Foundation of China (No. 40601096) 相似文献
998.
In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role
in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth
and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass
of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as
inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited
by C. oryzetorum, but no significant effect is found in this study.
Supported by the Innovation Project of CAS (No.KZCX2-YW-426), a Provincial Project of Hubei (No. 2006AA305A0402) and the National
Basic Research Program of China (973 Program, No. 2002CB 412306) 相似文献
999.
1000.
收集了宁夏固原2007年5月至2008年4月的12个降尘样品,陕西安塞2007年5—8月、2008年3—11月的13个降尘样品,并分别在两个降尘采样点附近采集了2个自然表土样品,对样品进行了总有机碳、粒度、磁化率分析,结果发现两地降尘的总有机质含量在1.029%~6.634%之间。粒度特征显示近源搬运占主导地位,同时,工业污染产生的PM10以下颗粒物贡献较小。降尘磁化率比自然表土明显偏高,但季节变化不明显。 相似文献