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Li J  Liu Y F  Yang X G  Li J 《农业工程》2006,26(8):2449-2456
Water-vapor flux over a planted coniferous forest ecosystem near Qianyanzhou, Jiangxi Province, China, was continuously measured with the eddy covariance technique for 2004. How environmental variables, including net radiation, air temperature, and soil moisture, affected water-vapor flux variation was studied in detail. Results showed that winter had the lowest monthly water-vapor flux value, whereas summer had the highest. The diurnal variation of water-vapor flux showed different patterns for clear and cloudy days. The annual total evapotranspiration was 736.1 mm. Regression analysis showed that daily water-vapor flux was significantly correlated with net radiation, air temperature, soil temperature, and soil heat flux on both clear and cloudy days, all in quadratic relationships. Stepwise regression analysis demonstrated that a different set of environmental factors controlled water-vapor flux on days with different weather conditions. From this study, it was clear that these environmental variables, especially net radiation and soil temperature, regulated water-vapor flux over the planted coniferous ecosystem.  相似文献   
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Exact locations of glacial refugia are relevant for the study of contemporary biodiversity, not only as places less disturbed during the climatic changes but also as sources of rapid expansion of the biota after the Last Glacial cycle. If continuously inhabited over several of the Quaternary glacial cycles, the refugia are readily identifiable by the accumulated genetic diversity. However, the sources of the Holocene range expansion, particularly important for the emergence of present-day bio- and phylogeographic patterns and for realistic estimation of species’ expansion rates, might have been located at the fringes of the glacial species ranges and lack unique lineages. This problem is pertinent when the variation is explored at slowly evolving genetic markers. We suggest that the location of such source refugia may be approximated by reconstructing the geographic location as a continuous trait evolving along the branches of a phylogenetic tree. We applied this approach, using the BEAST software, on two large southeast European land snail species: Caucasotachea vindobonensis and Helix thessalica. We found evidence for C. vindobonensis refugia in the western Balkans; notable is an apparently old refugium in Bosnia and Herzegovina. The plausible sources of the species’ Holocene range expansion, however, were located around the south-western end of the Carpathians. Although the source areas were likely similar in H. thessalica, some expansion sources suggested by the analyses (e.g., Podolia, Ukraine) appeared implausible and driven by sampling clustered in that area. The applied approach allows for additional exploitation of the mitochondrial data gathered during the past two decades of animal phylogeography studies.  相似文献   
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Human oral squamous cell carcinoma (OSCC) is the common head and neck malignancy in the world. While surgery, radiotherapy and chemotherapy are emerging as the standard treatment for OSCC patients, the outcome is limited to the recurrence and side effects. Therefore, patients with OSCC require alternative strategies for treatment. In this study, we aimed to explore the therapeutic effect and the mode of action of the novel curcumin analog, HO‐3867, against human OSCC cells. We analysed the cytotoxicity of HO‐3867 using MTT assay. In vitro mechanic studies were performed to determine whether MAPK pathway is involved in HO‐3867 induced cell apoptosis. As the results, we found HO‐3867 suppressed OSCC cells growth effectively. The flow cytometry data indicate that HO‐3867 induce the sub‐G1 phase. Moreover, we found that HO‐3867 induced cell apoptosis by triggering formation of activated caspase 3, caspase 8, caspase 9 and PARP. After dissecting MAPK pathway, we found HO‐3867 induced cell apoptosis via the c‐Jun N‐terminal kinase (JNK)1/2 pathway. Our results suggest that HO‐3867 is an effective anticancer agent as its induction of cell apoptosis through JNK1/2 pathway in human oral cancer cells.  相似文献   
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Juvenile calf oocytes represent an untapped source of germ plasm for reproduction. Reports on the developmental competence of calf oocytes have been controversial. In this research, oocytes were recovered after gonadotropin stimulation from Holstein calves (N = 10) at 2-3 mo of age (2-mo cycle) and again at 4-5 mo of age (4-mo cycle). The in vitro developmental competence was measured, and prestimulation follicle numbers (for 2-mo cycle) and poststimulation follicle numbers (both cycles) were obtained. The number of antral follicles doubled after stimulation (23.4 +/- 6.1 vs. 55.1 +/- 16.1) for the 2-mo cycle and for the 4-mo cycle (47.4 +/- 12.4). The number of follicles observed prior to stimulation in the 2-mo cycle was found to be highly correlated with the poststimulation oocyte recovery for both collection cycles (r = 0.95, 2-mo cycle; r = 0.81, 4-mo cycle). The majority (90-96%) of recovered oocytes were found to be usable for in vitro maturation and fertilization; of these, 41-42% cleaved and 10-11% developed to morulae or blastocysts. Eighty-four in vitro-produced embryos were transferred to synchronized recipients and resulted in 11 pregnancies, leading to 7 live (4 males, 3 females) and 2 dead (one male, one female) calves at full term. No significant differences were observed between the 2-mo and 4-mo collection cycles; however, 73% of the total pregnancies resulted from the 2-mo cycle. All pregnancies resulted from embryos of high-responding donors. The high correlation between the number of follicles prior to stimulation and the poststimulation response suggests the possibility of screening calves prior to stimulation for routine embryo production.  相似文献   
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A two-dimensional (2-D) liquid phase separation method, liquid isoelectric focusing followed by nonporous reversed-phase high performance liquid chromatography (HPLC), was used to separate proteins from human ovarian epithelial whole cell lysates. HPLC eluent was interfaced on-line to an electrospray ionization (ESI) time of flight (TOF) mass spectrometer to obtain accurate intact protein molecular weights (Mr). 2-D protein expression maps were generated displaying protein isoelectric point (pI) versus intact protein Mr. Resulting 2-D images effectively displayed quantitative differential protein expression in ovarian cancer cells versus non-neoplastic ovarian epithelial cells. Protein peak fractions were collected from the HPLC eluent, enzymatically digested, and analyzed by matrix-assisted laser desorption/ionization (MALDI) TOF-mass spectrometry (MS) peptide mass fingerprinting and by MALDI-quadrupole TOF tandem mass spectrometry peptide sequencing. Interlysate comparisons of differential protein expression between two ovarian adenocarcinoma cell lines, ES2 and MDAH-2774, and ovarian surface epithelial cells was performed. Five pI fractions from each sample were selected for comparative study and over 300 unique proteins were positively identified from the 2-D liquid expression maps using MS, which covered around 60% of proteins detected by on-line ESI-TOF-MS. This represents one of the most comprehensive proteomic analyses of ovarian cancer samples to date. Protein bands with significant up- or down-regulation in one cell line versus another as viewed in the 2-D expression maps were identified. This strategy may prove useful in identifying novel ovarian cancer marker proteins.  相似文献   
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Cordycepin has been shown to interfere with a myriad of molecular processes from RNA elongation to kinase activity, and prevents numerous inflammatory processes in animal models. Here we show in a mouse model of LPS-induced acute lung injury that cordycepin prevents airway neutrophilia via a robust blockade of expression of several inflammatory genes, including the adhesion molecule ICAM-1 and VCAM-1, the cytokine/chemokine MCP-1, MIP-1α, MIP-2 and KC, and the chemokine receptor CXCR2. Such a blockade appears to be related to a severe reduction in TNF-α expression. Interestingly, in an in vitro system of A549 epithelial cell inflammation, cordycepin effectively blocked LPS-induced, but not TNF-α-induced, VCAM-1 expression. Such effects correlated with a marked reduction in p65-NF-κB activation as assessed by its phosphorylation at serine-536 but without an apparent effect on its nuclear translocation. The effects of cordycepin on the expression of VCAM-1 and ICAM-1, and of NF-κB activation and nuclear translocation upon TNF-α stimulation resembled the effects achieved upon poly(ADP-ribose) polymerase (PARP) inhibition, suggesting that cordycepin may function as a PARP inhibitor. Indeed, cordycepin blocked H(2)O(2)-induced PARP activation in A549 cells. In a cell-free system, cordycepin inhibited PARP-1 activity at nanomolar concentrations. Similar to PARP inhibitors, cordycepin significantly induced killing of breast cancer susceptibility gene (BRCA1)-deficient MCF-7 cells, supporting its therapeutic use for the treatment of BRCA-deficient breast cancers. With added antiinflammatory characteristics, therapies that include cordycepin may prevent potential inflammation triggered by traditional chemotherapeutic drugs. Cordycepin, to the best of our knowledge, represents the first natural product possessing PARP inhibitory traits.  相似文献   
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