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991.
Imran Sajid Clarisse Blandine Fotso Fondja Yao Khaled Attia Shaaban Shahida Hasnain Hartmut Laatsch 《World journal of microbiology & biotechnology》2009,25(4):601-610
A culture collection of 110 indigenous Streptomyces strains originally isolated from saline farmlands (Punjab, Pakistan) using stringent methods was screened biologically and
chemically to investigate their potential for the production of bioactive secondary metabolites. In a biological screening
the crude extracts obtained from the culture broth of selected strains were analysed for their activity against a set of test
organisms, including Gram-positive, Gram-negative bacteria, fungi and microalgae using the disk diffusion bioassay method.
Additionally a cytotoxicity test was performed by means of the brine shrimp microwell cytotoxicity assay. In a chemical screening
each of the crude extracts was analysed by TLC using various staining reagents and by HPLC-MS/MS measurements. The results
depicted an impressive chemical diversity of crude extracts produced by these strains. The taxonomic status of the selected
strains was confirmed by preliminary physiological testing and 16S rRNA gene sequencing. 相似文献
992.
Christian Cortés-Rojo Elizabeth Calderón-Cortés Mónica Clemente-Guerrero Mirella Estrada-Villagómez Salvador Manzo-Avalos Ricardo Mejía-Zepeda Istvan Boldogh Alfredo Saavedra-Molina 《Journal of bioenergetics and biomembranes》2009,41(1):15-28
Lipoperoxidative damage to the respiratory chain proteins may account for disruption in mitochondrial electron transport chain
(ETC) function and could lead to an augment in the production of reactive oxygen species (ROS). To test this hypothesis, we
investigated the effects of lipoperoxidation on ETC function and cytochromes spectra of Saccharomyces cerevisiae mitochondria. We compared the effects of Fe2+ treatment on mitochondria isolated from yeast with native (lipoperoxidation-resistant) and modified (lipoperoxidation-sensitive)
fatty acid composition. Augmented sensitivity to oxidative stress was observed in the complex III-complex IV segment of the
ETC. Lipoperoxidation did not alter the cytochromes content. Under lipoperoxidative conditions, cytochrome c reduction by succinate was almost totally eliminated by superoxide dismutase and stigmatellin. Our results suggest that lipoperoxidation
impairs electron transfer mainly at cytochrome b in complex III, which leads to increased resistance to antimycin A and ROS generation due to an electron leak at the level
of the QO site of complex III. 相似文献
993.
Soltani F Mosaffa F Iranshahi M Karimi G Malekaneh M Haghighi F Behravan J 《Cell biology and toxicology》2009,25(3):291-296
The protective properties of a prenylated coumarin, umbelliprenin (UMB), on the human lymphocytes DNA lesions were tested.
Lymphocytes were isolated from blood samples taken from healthy volunteers. DNA breaks and resistance to H2O2-induced damage were measured using a single-cell microgel electrophoresis technique under alkaline conditions (comet assay).
Human lymphocytes were incubated in UMB (10, 25, 50, 100, 200, and 400 μM) alone or a combination of different concentrations
of UMB (10, 25, 50, 100, 200, and 400 μM) and 25 μM H2O2. Untreated cells, ascorbic acid (AA; 25, 50, 100, 200, and 400 μM) and H2O2 (25 μM) were considered as negative control, positive control, and the standard antioxidant agent for our study, respectively.
Single cells were analyzed with “TriTek Cometscore version 1.5” software. The DNA damage was expressed as percent tail DNA.
UMB exhibited a concentration-dependent increase in protection activity against DNA damage induced by 25 μM H2O2 (from 67.28% to 39.17%). The antigenotoxic activity of AA, in the range 0–50 μM, was greater than that of UMB. However, no
significant difference (p > 0.05) in the protective activity was found between UMB and AA at concentrations of approximately higher than 50 μM. 相似文献
994.
Tetsuro Tamaki Yoshiyasu Uchiyama Yoshinori Okada Kayoko Tono Masahiro Nitta Akio Hoshi Akira Akatsuka 《Histochemistry and cell biology》2009,132(1):59-70
Tissue inflammation and multiple cellular responses in the compensatory enlarged plantaris (OP Plt) muscle induced by surgical
ablation of synergistic muscles (soleus and gastrocnemius) were followed over 10 weeks after surgery. Contralateral surgery
was performed in adult Wistar male rats. Cellular responses in muscle fibers, blood vessels and nerve fibers were analyzed
by immunohistochemistry and electron microscopy. Severe muscle fiber damage and disappearance of capillaries associated with
apparent tissue edema were observed in the peripheral portion of OP Plt muscles during the first week, whereas central portions
were relatively preserved. Marked cell activation/proliferation was also mainly observed in peripheral portions. Similarly,
activated myogenic cells were seen not only inside but also outside of muscle fibers. The former were likely satellite cells
and the latter may be interstitial myogenic cells. One week after surgery, small muscle fibers, small arteries and capillaries
and several branched-muscle fibers were evident in the periphery, thus indicating new muscle fiber and blood vessel formation.
Proliferating cells were also detected in the nerve bundles in the Schwann cell position. These results indicate that the
compensatory stimulated/enlarged muscle is a suitable model for analyzing multiple physiological cellular responses in muscle–nerve–blood
vessel units under continuous stretch stimulation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
995.
Cho H Hur HW Kim SW Kim SH Kim JH Kim YT Lee K 《Cancer immunology, immunotherapy : CII》2009,58(1):15-23
Purpose Inflammatory cells can both suppress and stimulate tumor growth, and the influence of inflammatory cells on clinical outcome
has been the focus of many studies. The purpose of this study was to evaluate the effectiveness of the neutrophil to lymphocyte
ratio (NLR), a measure of the systemic inflammatory response, as an additional discriminative biomarker in epithelial ovarian
cancer and to determine whether it predicts survival and recurrence.
Methods We studied 192 patients with epithelial ovarian cancer, 173 with benign ovarian tumors, 229 with benign gynecologic disease,
and 405 healthy controls. Serum CA125 levels and leukocyte counts according to subtypes were recorded prior to treatment in
all study subjects. In epithelial ovarian cancer, the diagnostic usefulness of NLR, in combination with CA125, was evaluated.
The correlation between NLR and overall and disease-free survival was analyzed using both univariate and multivariate analyses
adjusting for the known prognostic factors (age, stage, cell type, and grade).
Results Preoperative NLR in ovarian cancer subjects (mean 6.02) was significantly higher than that in benign ovarian tumor subjects
(mean 2.57), benign gynecologic disease subjects (mean 2.55), and healthy controls (mean 1.98) (P < 0.001). The sensitivity and specificity of NLR in detecting ovarian cancer was 66.1% (95% CI, 59.52–72.68%) and 82.7% (95%
CI, 79.02–86.38%), respectively (cutoff value: 2.60). In early stage ovarian cancer, CA125 was not elevated in 19 out of 49
patients. Seven (36.8%) of these 19 patients were NLR positive. On Cox multivariate analysis, NLR positive, stage III/IV,
and older age were independent poor prognostic factors, and being NLR positive was the most powerful predictive variable (Hazard
Ratio = 8.42 [95% CI: 1.09–64.84], P = 0.041).
Conclusions Our findings provide evidence for the association between NLR and epithelial ovarian cancer. Preoperative NLR, in combination
with CA125, may represent a simple and cost-effective method of identifying ovarian cancers, and an elevated NLR may predict
an adverse outcome in ovarian cancer. 相似文献
996.
During CNS development, oligodendrocyte progenitor (OP) cells migrate from germinal zones to presumptive white matter tracts
to generate myelinating oligodendrocytes. In vitro and in vivo studies indicate that platelet-derived growth factor-A (PDGF-A)
is a potent chemoattractant for OP cells and important for normal distribution throughout the developing CNS. However, PDGF-A
does not localize in concentration gradients corresponding to OP migratory pathways, as would be expected for a chemoattractant
to direct migration. Therefore, the mechanism by which PDGF-A regulates OP distribution remains to be clarified. Here we show
that PDGF-A induces OP migration and continuous exposure to PDGF-A is not required to maintain migration. Using pharmacological
inhibitors, we show that a self-sustaining extracellular-regulated-kinase signaling pathway drives OP migration for up to
72 hours after the initial PDGF stimulus. These findings indicate PDGF-A may act to mobilize OP cells that then respond to
distinct directional signals to distribute appropriately within the CNS.
Special issue article in honor of Dr. George DeVries. 相似文献
997.
Klára Řeháková Eliška Zapomělová Ondřej Prášil Jana Veselá Hana Medová Aharon Oren 《Hydrobiologia》2009,636(1):77-88
There are several conflicting hypothesis that deal with the influence of flooding in the natural river–floodplain systems.
According to the Flood Pulse Concept, the flood pulses are not considered to be a disturbance, while some recent studies have
proven that floods can be a disturbance factor of phytoplankton development. In order to test whether flooding acts as a disturbance
factor in the shallow Danubian floodplain lake (Lake Sakadaš), phytoplankton dynamics was investigated during two different
hydrological years—extremely dry (2003) without flooding and usually flooded (2004). A total of 18 phytoplankton functional
groups were established. The sequence of phytoplankton seasonality can be summarized P/D → E (W1, W2) → C/P (only in potamophase) → S2/H1/SN/S1 → W1/W2 → P/D. The canonical correspondence analysis (CCA) demonstrated that the water level was a significant environmental
variable in 2004. Due to the higher total biomass of Bacillariophyceae established under potamophase conditions, floodings
in the early spring seem to be a stimulating factor for phytoplankton development. On the other hand, the flood pulses in
May and June had dilution effects on nutrients, so that a significantly lower phytoplankton biomass was established indicating
that flooding pulses can be regarded as a disturbance event. Such conditions supported diatom development (D, P, C species)
and prolonged its dominance in the total phytoplankton biomass. A long-lasting Cyanoprokaryota bloom (various filamentous
species—S1, S2, SN and H1 representatives) with very high biomass characterized the limnophase (dry conditions) in summer and autumn of both
years. In-lake variables (lake morphology, internal loadings of nutrients from sediments, light conditions) seem to be important
for the appearance of Cyanoprokaryota bloom. The equilibrium phase was found during the Cyanoprokaryota bloom only in the
extremely dry year. This study showed that depending on the time scale occurrence, flood pulses can be a stimulating or a
disturbance factor for phytoplankton development in Lake Sakadaš.
Handling editor: J. Padisak 相似文献
998.
Jérôme Lemaître Daniel Fortin Pierre-Olivier Montiglio Marcel Darveau 《Oecologia》2009,159(2):283-294
Parasites can play an important role in the dynamics of host populations, but empirical evidence remains sparse. We investigated
the role of bot fly (Cuterebra spp.) parasitism in red-backed voles (Myodes gapperi) by first assessing the impacts of the parasite on the probability of vole survival under stressful conditions as well as
on the reproductive activity of females. We then identified the main factors driving both the individual risk of infection
and the abundance of bot flies inside red-backed voles. Finally, we evaluated the impacts of bot fly prevalence on the growth
rate of vole populations between mid-July and mid-August. Thirty-six populations of red-backed voles were sampled in the boreal
forest of Québec, Canada. The presence and the abundance of parasites in voles, two host life history traits (sex and body
condition), three indices of habitat complexity (tree basal area, sapling basal area, coarse woody debris volume), and vole
abundance were considered in models evaluating the effects of bot flies on host populations. We found that the probability
of survival of red-backed voles in live traps decreased with bot fly infection. Both the individual risk of infection and
the abundance of bot flies in red-backed voles were driven mainly by vole abundance rather than by the two host life history
traits or the three variables of habitat complexity. Parasitism had population consequences: bot fly prevalence was linked
to a decrease in short-term growth rate of vole populations over the summer. We found that bot flies have the potential to
reduce survival of red-backed voles, an effect that may apply to large portions of populations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
999.
Molecular identification and dynamics of microbial communities in reactor treating organic household waste 总被引:1,自引:0,他引:1
Juliana Cardinali-Rezende Renan B. Debarry Luis F. D. B. Colturato Eduardo V. Carneiro Edmar Chartone-Souza Andrea M. A. Nascimento 《Applied microbiology and biotechnology》2009,84(4):777-789
The prokaryotic diversity associated with organic household waste (OHW), leachate (start-up inoculum), and mesophilic anaerobic
digestion processes in the degradation of OHW for 44 and 90 days was investigated using a culture-independent approach. Bacterial
and archaeal 16S rRNA and mcrA gene clone libraries were constructed from community DNA preparations. Bacterial clones were affiliated with 13 phyla, of
which Firmicutes, Proteobacteria, and Bacteroidetes were represented in all libraries, whereas Actinobacteria, Thermotogae, Lentisphaerae, Acidobacteria, Chloroflexi, Cyanobacteria, Synergistetes, Spirochaetes, Deferribacteres, and Deinococcus-Thermus were exclusively identified in a single library. Within the Archaea domain, the Euryarchaeota phylum was the only one represented. Corresponding sequences were associated with the following orders of hydrogenotrophic
methanogens: Methanomicrobiales (Methanoculleus genus) and Methanobacteriales (Methanosphaera and Methanobacterium genera). One archaeal clone was not affiliated with any order and may represent a novel taxon. Diversity indices showed greater
diversity of Bacteria when compared to methanogenic Archaea. 相似文献
1000.