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841.
Four species of cyclomorphic Daphnia (D.pulex, D.galeata mendotae,D.retrocurva, D.lumholtzi) were exposed to the insecticide carbarylfor a short term (84 h) from the final embryonic stageto the first instar. Daphnia pulex formed neckteeth, and theremaining three Daphnia species developed high helmets and longtailspines. The results suggest that the development of suchprotuberant structures (anti-predator morphologies) in responseto the insecticide exposure is a general phenomenon in Daphnia,and that stimuli on the nervous system of Daphnia may inducethe morphological changes, which originally evolved as a responseto predator kairomone. Two clones of D.pulcx were examined anda clone which was more sensitive to the predator Chaobonts kairomonethan another developed more marked neckteeth in response tocarbaryl, suggesting that the sensitivity in morphological responseto the insecticide may be related to the sensitivity to thekairomone.
1Present and permanent address: Regional Environment Division,National Institute for Environmental Studies Onogawa, Tsukuba,Ibaraki 305, Japan 相似文献
842.
Takayuki Nagakubo Akitsu Nagasawa Hideo Ohkawa 《Plant Cell, Tissue and Organ Culture》1993,32(2):175-183
We developed a novel micropropagation method for garlic (Allium sativum L.) by the combination of initial shoot-tip culture, shoot multiplication and in vitro bulblet formation. Garlic shoot-tips were cultured on LS medium containing 1 M indole-3-acetic acid (IAA) and 1 M 6-benzyladenine (BA) to regenerate proliferative shoots. These shoot-tips produced multiple shoots when transferred to modified LS medium containing 5 M 1-naphthaleneacetic acid (NAA) and 10 M BA, and cultured at 20°C under 12-h light conditions. Higher ratios of KNO3/NH4Cl in the media promoted multiple shoot formation, together with suppressing vitrification of these shoots. The proliferated shoots of early maturing cultivars produced bulblets by culture on LS growth regulator-free medium at 25°C under 16-h light. On the other hand, the late maturing cultivar, Howaito-roppen, formed bulblets after a low temperature treatment of the proliferated shoots for 6 months followed by culture on LS medium containing 6 to 12% sucrose for two months. The dormancy of the bulblets of cv. Howaito-roppen was broken by successive treatments at a high (35°C), a middle (20°C), and then a low (5°C) temperature.Abbreviations IAA
indole-3-acetic acid
- NAA
1-naphthaleneacetic acid
- BA
6-benzyladenine
- LS
Linsmaier and Skoog macro- and microelements 相似文献
843.
用1例日本滑膜肉瘤(SS)患者的瘤组织标本接种裸鼠,获得了肿瘤生长。亲本肿瘤与裸鼠肿瘤在病理组织形态上存在一定差异,但两者的免疫组织化学特征相同。染色体分析表明,SS细胞株存在染色体数目和结构异常,患者外周血淋巴细胞染色体核型为正常女性,46,XX。 SS细胞株巴氏小体检出率低于对照,其正常X染色体比易位X染色体晚复制17小时。DNA印迹实验表明,SS DNA存在D2S3座位等位片段丢失,D1S57,D17S5和D13S30座位基因的部分缺失,但无DXS7,DXS14,和D2S44座位基因改变。 相似文献
844.
The mycofloral succession on the needles ofPinus sylvestris was investigated in Tübingen, southwest Germany. Dead needles attached to the branches (D-type), those caught on branches (C-type) and three types of fallen needles, i.e., freshly fallen (L-type), slightly discolored (OL-type) and almost black needles (F-type) were examined for their fungal flora. Common primary saprophytes were rich on the dead needles on the tree, and on the L-type needles. They were replaced by successive species that contained the well-known species preferring pine needles as their substratum, such asVerticicladium trifidum orSympodiella acicola. Their ecological niches in pine leaf litter and their distribution patterns from a biogeographical viewpoint were discussed. 相似文献
845.
The biotransformation of foreign substrates with suspension cells of Nicotiana tabacum was tested with (4R)-(?)- and (4S)-(+)-carvones, ( 相似文献
846.
The receptaculum seminis, opening into the female genital tract, is found only in the metastriate ixodid ticks. An endospermatophore that has been inserted into the female genital aperture at copulation is first stored in the receptaculum seminis, where spermiogenesis is completed before the sperm ascend the oviducts. The receptaculum seminis consists of a simple cuticularized epithelium. Epithelial cells in sexually matured females develop during feeding and become active in secretion. Secretions discharged from epithelial cells are released into the lumen of this organ through the cuticle and may act on the wall of the inserted endospermatophore. The fact that resumption of spermiogenesis (spermateleosis) has already occurred before destruction of the endospermatophore just after copulation suggests that secretions from epithelial cells of the receptaculum seminis are not the trigger of spermateleosis, but a destructive agent of the endospermatophore wall. J Morphol 231:143–147, 1997. © 1997 Wiley-Liss, Inc. 相似文献
847.
848.
Takayuki Hoson Kouichi Soga Ryuji Mori Mizue Saiki Kazuyuki Wakabayashi Seiichiro Kamisaka Shigeki Kamigaichi Sachiko Aizawa Izumi Yoshizaki Chiaki Mukai Toru Shimazu Keiji Fukui Masamichi Yamashita 《Journal of plant research》1999,112(4):477-486
Oryza sativa L.) and Arabidopsis (A. thaliana L.) were cultivated for 68.5 hr in the RICE experiment on board during Space Shuttle STS-95 mission, and changes in their
growth and morphology were analyzed. Microgravity in space stimulated elongation growth of both rice coleoptiles and Arabidopsis hypocotyls by making their cell walls extensible. In space, rice coleoptiles showed an inclination toward the caryopsis in
the basal region and also a spontaneous curvature in the same direction in the elongating region. These inclinations and curvatures
were more prominent in the Koshihikari cultivar compared to a dwarf cultivar, Tan-ginbozu. Rice roots elongated in various
directions including into the air on orbit, but two thirds of the roots formed a constant angle with the axis of the caryopsis.
In space, Arabidopsis hypocotyls also elongated in a variety of directions and about 10% of the hypocotyls grew into the agar medium. No clear
curvatures were observed in the elongating region of Arabidopsis hypocotyls. Such a morphology of both types of seedlings was fundamentally similar to that observed on a 3-D clinostat. Thus,
it was confirmed by the RICE experiment that rice and Arabidopsis seedlings perform an automorphogenesis under not only simulated but also true microgravity conditions.
Received 13 September 1999/ Accepted in revised form 12 October 1999 相似文献
849.
Kouichi Soga Keita Harada Kazuyuki Wakabayashi Takayuki Hoson Seiichiro Kamisaka 《Journal of plant research》1999,112(3):273-278
Zea mays L. cv. Cross Bantam T51) coleoptiles and mesocotyls was suppressed by hypergravity at 30 g and above. Acceleration at 300 g significantly decreased the mechanical extensibility of cell walls of both organs. Hypergravity increased the amounts of
hemicellulose and cellulose per unit length in mesocotyl walls, but not in coleoptile walls. The weight-average molecular
masses of hemicellulosic polysaccharides were also increased by hypergravity in both organs. On the other hand, the activities
of β-glucanases extracted from coleoptile and mesocotyl cell walls were decreased by hypergravity. These results suggest that
the decreased activities of β-glucanases by hypergravity cause an increase in the molecular mass of hemicellulosic polysaccharides
of both organs. The upshift of molecular mass of hemicellulosic polysaccharides as well as the thickening of cell walls under
hypergravity conditions seems to be involved in making the cell wall mechanically rigid, thereby inhibiting elongation growth
of maize coleoptiles and mesocotyls.
Received 22 February 1999/ Accepted in revised form 20 April 1999 相似文献
850.
Atsushi Kimura Junji Ohnishi Hikari Okimura Takashi Hamabata Takayuki Takahashi 《Molecular reproduction and development》1998,50(2):121-127
Prolyl endopeptidase (EC3.4.21.26) has been considered a unique intracellular enzyme catalyzing internal peptide bond hydrolysis of Pro-X. In this study, the distribution of prolyl endopeptidase activity and its mRNA was investigated in the follicles of porcine ovary. Both follicular fluid and granulosa cell fractions from small follicles showed higher activity than those from large follicles. Molecular cloning and Northern blot analysis suggested that only one species of prolyl endopeptidase gene was expressed in the ovary. In addition, in situ hybridization study revealed that the prolyl endopeptidase mRNA expresssion was more noticeable in the granulosa cell layers of small ovarian follicles than in those of large follicles, suggesting its importance in the early stage of follicular development. Mol. Reprod. Dev. 50:121–127, 1998. © 1998 Wiley-Liss, Inc. 相似文献