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41.
Responses of soil microbial communities to prescribed burning in two paired vegetation sites in southern China 总被引:4,自引:0,他引:4
Sun Yuxin Wu Jianping Shao Yuanhu Zhou Lixia Mai Bixian Lin Yongbiao Fu Shenglei 《Ecological Research》2011,26(3):669-677
Prescribed burning is a common site preparation practice for forest plantation in southern China. However, the effects of
prescribed burning on soil microbial communities are poorly understood. This study examined changes in microbial community
structure, measured by phospholipid fatty acids (PLFAs), after a single prescribed burning in two paired vegetation sites
in southern China. The results showed that the total amount of PLFA (totPLFA) was similar under two vegetation types in the
wet season but differed among vegetation type in the dry season, and was affected significantly by burning treatment only
in the wet season. Bacterial PLFA (bactPLFA) and fungal PLFA (fungPLFA) in burned plots all decreased compared to the unburned
plots in both seasons (P = 0.059). Fungi appeared more sensitive to prescribed burning than bacteria. Both G+ bacterial PLFA and G− bacterial PLFA were decreased by the burning treatment in both dry and wet seasons. Principal component analysis of PLFAs
showed that the burning treatment induced a shift in soil microbial community structure. The variation in soil microbial community
structure was correlated significantly to soil organic carbon, total nitrogen, available phosphorus and exchangeable potassium.
Our results suggest that prescribed burning results in short-term changes in soil microbial communities but the long-term
effects of prescribed burning on soil microbial community remain unknown and merit further investigation. 相似文献
42.
Ghani FI Yamazaki H Iwata S Okamoto T Aoe K Okabe K Mimura Y Fujimoto N Kishimoto T Yamada T Xu CW Morimoto C 《Biochemical and biophysical research communications》2011,(2):735-742
Malignant mesothelioma (MM) is an aggressive and therapy-resistant neoplasm arising from the pleural mesothelial cells and usually associated with long-term asbestos exposure. Recent studies suggest that tumors contain cancer stem cells (CSCs) and their stem cell characteristics are thought to confer therapy-resistance. However, whether MM cell has any stem cell characteristics is not known. To understand the molecular basis of MM, we first performed serial transplantation of surgical samples into NOD/SCID mice and established new cell lines. Next, we performed marker analysis of the MM cell lines and found that many of them contain SP cells and expressed several putative CSC markers such as CD9, CD24, and CD26. Interestingly, expression of CD26 closely correlated with that of CD24 in some cases. Sorting and culture assay revealed that SP and CD24+ cells proliferated by asymmetric cell division-like manner. In addition, CD9+ and CD24+ cells have higher potential to generate spheroid colony than negative cells in the stem cell medium. Moreover, these marker-positive cells have clear tendency to generate larger tumors in mouse transplantation assay. Taken together, our data suggest that SP, CD9, CD24, and CD26 are CSC markers of MM and could be used as novel therapeutic targets. 相似文献
43.
West M Mhatre M Ceballos A Floyd RA Grammas P Gabbita SP Hamdheydari L Mai T Mou S Pye QN Stewart C West S Williamson KS Zemlan F Hensley K 《Journal of neurochemistry》2004,91(1):133-143
Familial forms of amyotrophic lateral sclerosis (ALS) can be caused by mutations in copper, zinc-superoxide dismutase (SOD1). Mice expressing SOD1 mutants demonstrate a robust neuroinflammatory reaction characterized, in part, by up-regulation of tumor necrosis factor alpha (TNFalpha) and its primary receptor TNF-RI. In an effort to identify small molecule inhibitors of neuroinflammation useful in treatment of ALS, a microglial culture system was established to identify TNFalpha antagonists. Walker EOC-20 microglia cells were stimulated with recombinant TNFalpha, with or without inhibitors, and the cell response was indexed by NO2- output. Three hundred and fifty-five rationally selected compounds were included in this bioassay. The arachidonic acid 5-lipoxygenase (5LOX) and tyrosine kinase inhibitor nordihydroguaiaretic acid (NDGA), a natural dicatechol, was one of the most potent non-cytotoxic antagonists tested (IC50 8 +/- 3 microm). Investigation of the G93A-SOD1 mouse model for ALS revealed increased message and protein levels of 5LOX at 120 days of age. Oral NDGA (2500 p.p.m.) significantly extended lifespan and slowed motor dysfunction in this mouse, when administration was begun relatively late in life (90 days). NDGA extended median total lifespan of G93A-SOD1 mice by 10%, and life expectancy following start of treatment was extended by 32%. Disease-associated gliosis and cleaved microtubule-associated tau protein, an indicator of axon damage, were likewise reduced by NDGA. Thus, TNFalpha antagonists and especially 5LOX inhibitors might offer new opportunities for treatment of ALS. 相似文献
44.
Heithem Ben Abdallah Hans-Jörg Mai Ana Álvarez-Fernández Javier Abadía Petra Bauer 《Plant and Soil》2017,413(1-2):45-57
Aims
Urban soils are the basis of many ecosystem services in cities. Here, we examine formerly residential vacant lot soils in Cleveland, Ohio and Detroit, Michigan, USA for their potential to provide multiple ecosystem services. We examine two key contrasts: 1) differences between cities and 2) differences within vacant lots created during demolition, specifically pre-existing (i.e., prior to demolition) soils outside of the building footprint and fill soils added within the former building’s footprint.Methods
Deep soil cores were collected from vacant lots in Cleveland and Detroit. Soil properties that are proxies for three ecosystem services were measured: hydraulic conductivity for stormwater retention, topsoil depth and soil nitrogen (N) level for support for plant growth, and soil carbon (C) content for C storage.Results
Both city and soil group contrasts created distinct ecosystem service provisioning based on proxy measures. Cleveland soils had greater hydraulic conductivity and greater soil C and N levels but thinner topsoil layers than Detroit. Within vacant lots of both cities, pre-existing soils had greater soil C and N levels, but lower hydraulic conductivity values than fill soils.Conclusions
Soil properties of vacant lots were generally suitable for providing multiple ecosystem services. City-level differences in soil properties created differences in ecosystem service potential between cities and these differences were evident in pre-existing and fill soils. When comparing between cities, though, fill soils were more similar than pre-existing soils indicating some homogenization of ecosystem service potential with greater redistribution of soil.45.
46.
Toshiyuki Takahashi Mayuko Sato Kiminori Toyooka Ryo Matsuzaki Kaoru Kawafune Mai Kawamura Kazuo Okuda Hisayoshi Nozaki 《Journal of phycology》2014,50(6):1058-1069
Cyanophora is an important glaucophyte genus of unicellular biflagellates that may have retained ancestral features of photosynthetic eukaryotes. The nuclear genome of Cyanophora was recently sequenced, but taxonomic studies of more than two strains are lacking for this genus. Furthermore, no study has used molecular methods to taxonomically delineate Cyanophora species. Here, we delimited the species of Cyanophora using light and electron microscopy, combined with molecular data from several globally distributed strains, including one newly established. Using a light microscope, we identified two distinct morphological groups: one with ovoid to ellipsoidal vegetative cells and another with dorsoventrally flattened or broad, bean‐shaped vegetative cells containing duplicated plastids. Our light and scanning electron microscopy clearly distinguished three species with ovoid to ellipsoidal cells (C. paradoxa Korshikov, C. cuspidata Tos.Takah. & Nozaki sp. nov., and C. kugrensii Tos.Takah. & Nozaki sp. nov.) and two species with broad, bean‐shaped cells (C. biloba Kugrens, B.L.Clay, C.J.Mey. & R.E.Lee and C. sudae Tos.Takah. & Nozaki sp. nov.) based on differences in cell shape and surface ornamentations of the vegetative cells under the field‐emission scanning electron microscope. Molecular phylogenetic analyses of P700 chl a apoprotein A2 (psaB) genes and internal transcribed spacer (ITS) regions of nuclear ribosomal DNA (rDNA), as well as a comparison of secondary structures of nuclear rDNA ITS‐2 and genetic distances of psaB genes, supported the delineation of five morphological species of Cyanophora. 相似文献
47.
Nanoflake‐Assembled Hierarchical Na3V2(PO4)3/C Microflowers: Superior Li Storage Performance and Insertion/Extraction Mechanism 下载免费PDF全文
Qinyou An Fangyu Xiong Qiulong Wei Jinzhi Sheng Liang He Dongling Ma Yan Yao Liqiang Mai 《Liver Transplantation》2015,5(10)
Na3V2(PO4)3 (NVP) has excellent electrochemical stability and fast ion diffusion coefficient due to the 3D Na+ ion superionic conductor framework, which make it an attractive cathode material for lithium ion batteries (LIBs). However, the electrochemical performance of NVP needs to be further improved for applications in electric vehicles and hybrid electric vehicles. Here, nanoflake‐assembled hierarchical NVP/C microflowers are synthesized using a facile method. The structure of as‐synthesized materials enhances the electrochemical performance by improving the electron conductivity, increasing electrode–electrolyte contact area, and shortening the diffusion distance. The as‐synthesized material exhibits a high capacity (230 mAh g?1), excellent cycling stability (83.6% of the initial capacity is retained after 5000 cycles), and remarkable rate performance (91 C) in hybrid LIBs. Meanwhile, the hybrid LIBs with the structure of NVP || 1 m LiPF6/EC (ethylene carbonate) + DMC (dimethyl carbonate) || NVP and Li4Ti5O12 || 1 m LiPF6/EC + DMC || NVP are assembled and display capacities of 79 and 73 mAh g?1, respectively. The insertion/extraction mechanism of NVP is systematically investigated, based on in situ X‐ray diffraction. The superior electrochemical performance, the design of hybrid LIBs, and the insertion/extraction mechanism investigation will have profound implications for developing safe and stable, high‐energy, and high‐power LIBs. 相似文献
48.
Accumulation of the proteolytic marker peptide ubiquitin in the trophoblast of mammalian blastocysts
Sutovsky P Motlik J Neuber E Pavlok A Schatten G Palecek J Hyttel P Adebayo OT Adwan K Alberio R Bagis H Bataineh Z Bjerregaard B Bodo S Bryja V Carrington M Couf M de la Fuente R Diblik J Esner M Forejt J Fulka J Geussova G Gjorret JO Libik M Hampl A Hassane MS Houshmand M Hozak P Jezova M Kania G Kanka J Kandil OM Kishimoto T Klima J Kohoutek J Kopska T Kubelka M Lapathitis G Laurincik J Lefevre B Mihalik J Novakova M Oko R Omelka R Owiny D Pachernik J Pacholikova J Peknicova J Pesty A 《Cloning and stem cells》2001,3(3):157-161
Ubiquitination is a universal protein degradation pathway in which the molecules of 8.5-kDa proteolytic peptide ubiquitin are covalently attached to the epsilon-amino group of the substrate's lysine residues. Little is known about the importance of this highly conserved mechanism for protein recycling in mammalian gametogenesis and fertilization. The data obtained by the students and faculty of the international training course Window to the Zygote 2000 demonstrate the accumulation of ubiquitin-cross-reactive structures in the trophoblast, but not in the inner cell mass of the expanding bovine and mouse blastocysts. This observation suggests that a major burst of ubiquitin-dependent proteolysis occurs in the trophoblast of mammalian peri-implantation embryos. This event may be important for the success of blastocyst hatching, differentiation of embryonic stem cells into soma and germ line, and/or implantation in both naturally conceived and reconstructed mammalian embryos. 相似文献
49.
Takeo Kishimoto Ryoko Kuriyama Hisayo Kondo Haruo Kanatani 《Experimental cell research》1982,137(1):121-126
It has been known in amphibians and starfishes that a cytoplasmic factor called maturation-promoting factor (MPF), produced in maturing oocytes under the influence of the maturation-inducing hormones, can induce germinal vesicle breakdown (GVBD) and the subsequent process of meiotic maturation. The present study revealed that injection of cytoplasm of maturing starfish oocytes (starfish MPF) into immature sea cucumber oocytes brought about maturation of the recipients. Amphibian MPF obtained from mature oocytes of Xenopus laevis or Bufo bufo was found to induce maturation of starfish oocytes following injection. Cytoplasm taken from cleaving starfish blastomeres induced maturation when injected into immature starfish oocytes. The maturation-inducing activity of cytoplasm of starfish blastomeres changed along with the mitotic cell cycle during 1- to 4-cell stages so far tested and reached a peak just before cleaving. Furthermore, an extract of mammalian cultured cells, CHO or V-79, synchronized in M phase, induced GVBD in starfish oocytes following injection, whereas S phase extract had little activity. These facts suggest that MPF generally brings about nuclear membrane breakdown in both meiosis and mitosis, and that the nature of MPF is very similar among vertebrates and invertebrates. 相似文献
50.