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991.
Cycloxygenase-2 catalyzes the synthesis of prostaglandins from arachidonic acid and this enzyme has been implicated in the
metastasis of gastric cancer. In order to examine the significance of cycloxygenase-2 (Cox-2) in the survival and proliferation
of gastric cancer cells, we have stably overexpressed an antisense Cox-2 in two gastric cancer cell lines, SGC7901 and AGS,
in order to reduce the expression of this protein. The sense and antisense Cox-2 expression vectors were created by cloning
COX-2 cDNA, in pIRES2-EGFP plasmid. Cox-2 gene expression was monitored by RT-PCR and Western blotting and the results indicated that cells with antisense
Cox-2 construct had significantly reduced Cox-2 expression in comparison to the cells that received sense-Cox-2 plasmid. Reduction
of Cox-2 expression in SGC7901 and AGS gastric cancer cells led to markedly decreased proliferation. The metastatic capability
of the two cell lines, as assessed by in vitro colony formation assay, is also significantly compromised by lowered Cox-2
expression. Thus, this study demonstrates that Cox-2 activity is necessary for the proliferation and metastasis of gastric
cancer cells. 相似文献
992.
Inflammatory responses are an important element in the atherosclerotic process. Therefore, inflammatory markers can potentially
serve as predictors of cardiovascular risk. However, the existing data are limited and controversial. We conducted a prospective
cohort study with 263 patients with first acute ST-segment elevation myocardial infarction (STEMI) who were admitted to our
Hospital within 6 h after the symptoms onset. Clinical data were recorded and serum admission levels of interleukin-6 (IL-6),
soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble P-selectin
(sP-selectin) were determined. The patients were then followed up for 3 years to document cardiovascular mortality. During
the follow-up, 34 patients died from cardiovascular causes. The admission levels of IL-6 were significantly higher in these
patients, whereas sICAM-1, sVCAM-1, and sP-selectin were comparable between these and the survived patients. The Kaplan–Meier
plots revealed a significant increase in cardiovascular mortality with increasing levels of IL-6 (P = 0.0002, χ2 test). The logistic regression analysis indicated that IL-6 was an independent predictor for cardiovascular mortality. To
conclude, our findings indicate that elevated admission levels of IL-6, but not soluble adhesion molecules, provide valuable
information for risk assessment of long-term cardiovascular mortality in patients with STEMI. 相似文献
993.
The molecular architecture of centromere-specific nucleosomes containing histone variant CenH3 is controversial. We have biochemically reconstituted two distinct populations of nucleosomes containing Saccharomyces cerevisiae CenH3 (Cse4). Reconstitution of octameric nucleosomes containing histones Cse4/H4/H2A/H2B is robust on noncentromere DNA, but inefficient on AT-rich centromere DNA. However, nonhistone Scm3, which is required for Cse4 deposition in?vivo, facilitates in?vitro reconstitution of Cse4/H4/Scm3 complexes on AT-rich centromere sequences. Scm3 has a nonspecific DNA binding domain that shows preference for AT-rich DNA and a histone chaperone domain that promotes specific loading of Cse4/H4. In live cells, Scm3-GFP is enriched at centromeres in all cell cycle phases. Chromatin immunoprecipitation confirms that Scm3 occupies centromere DNA throughout the cell cycle, even when Cse4 and H4 are temporarily dislodged in S phase. These findings suggest a model in which centromere-bound Scm3 aids recruitment of Cse4/H4 to assemble and maintain an H2A/H2B-deficient centromeric nucleosome. 相似文献
994.
Zichen?Zhang Jianghua?Li Long?LiuEmail author Jun?Sun Zhaozhe?Hua Guocheng?Du Jian?Chen 《Biotechnology and Bioprocess Engineering》2011,16(1):107-113
The study aimed to produce 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) via the transglycosylation reaction by α-cyclodextrin glucanotransferase (α- CGTase) from recombinant Escherichia coli with L-ascorbic acid (AA) and β-cyclodextrin (β-CD) as the substrates. Liquid chromatography-tandem mass spectrometry analysis
was conducted for AA-2G identification, and the glucoamylase treatment was carried out to produce AA-2G from AA-2-oilgosaccharides.
The optimal temperature and pH for the enzymatic AA-2G production were 37°C and 5.5, respectively, and the optimal α-CGTase
concentration and substrate mass ratio (AA:β-CD) for AA-2G synthesis were 160 U/mL and 1:1, respectively. At these optimal
process conditions, maximal AA-2G production reached 13 g/L. This is the first report regarding the process optimization of
enzymatic AA-2G production by α-CGTase from recombinant E. coli. The results may be useful for the industrial scale production of AA-2G. 相似文献
995.
Manganese superoxide dismutase (MnSOD) is over-expressed in most brain tumours, and high MnSOD expression is associated with poor prognosis. The mechanisms still remain largely unknown. In the present study, the elevation of hydrogen peroxide (H(2)O(2)) level and the enhancement of glioma migration/invasion by over-expression of MnSOD were demonstrated. Subsequent studies showed that over-expression of MnSOD significantly increased the activation of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-3-kinases (PI3Ks), including AKTs, s6-ribosomal protein, ERKs and JNKs. Over-expression of MnSOD was also associated with elevations of matrix metalloproteinases-1(MMP-1) and MMP-9 protein. The promotion of migration/invasion, activation of PI3Ks and MAPKs and up-regulation of MMPs were inhibited by the general reactive oxygen species scavenger N-acetyl-l-cysteine (NAC), over-expression of the H(2)O(2)-detoxifying enzyme mitochondrial catalase (mCat) and specific inhibitors of AKTs or ERKs. Collectively, our study indicated that H(2)O(2) would contribute to the MnSOD-promoted migration/invasion in glioma cells through activation of AKTs and ERKs. This study provided new molecular insights into the understanding of glioma migration and invasion. 相似文献
996.
Wang H Liu H Zheng ZM Zhang KB Wang TP Sribastav SS Liu WS Liu T 《Apoptosis : an international journal on programmed cell death》2011,16(10):990-1003
Intervertebral disc (IVD) cell apoptosis has been suggested to play an important role in promoting the degeneration process.
It has been demonstrated that IVD cell apoptosis occurs through either death receptor, mitochondrial or endoplasmic reticulum
(ER) pathway. Our study aimed to explore the relationship among these three pathways and grade of IVD degeneration (IVDD).
IVDs were collected from patients with lumbar fracture, vertebral tumor, disc herniation or spondylolisthesis. IVDs were distinguished
by MRI and histomorphological examination, cell apoptosis was detected by TUNEL staining. Biomarkers of these three apoptosis
pathways were detected by RT-PCR and Western blot. Furthermore, the correlation between apoptosis pathways biomarkers and
disc pathology were analyzed. Nucleus pulposus cell density decreased with degeneration process, and increased apoptotic ratio.
ER pathway was predominant in mild stage of IVDD (GRP78, GADD153 upregulation and caspase-4 activation), death receptor pathway
was predominant in mild and moderate stages (Fas, FasL up-regulation and caspase-8 activation) and mitochondrial pathway was
predominant in moderate and severe stages (Bcl-2 down-regulation, Bax up-regulation, cytochrome-c accumulation in cytoplasm
and caspase-9 activation). There were significant differences in the expressions of Fas, FasL, Bax, GADD153, cytochrome-c
and cleaved caspase-8/9/3 between contained and non-contained discs. In conclusion, apoptosis occurs via these three apoptosis
pathways together in IVDD. ER pathway plays a more critical role in the mild compared to moderate and severe stages, death
receptor pathway in mild and moderate, and mitochondrial pathway in moderate and severe stages of IVDD. Disc cells apoptosis
may progress rapidly after herniation, and may depend on the type of herniation. 相似文献
997.
Riddick G Song H Ahn S Walling J Borges-Rivera D Zhang W Fine HA 《Bioinformatics (Oxford, England)》2011,27(2):220-224
MOTIVATION: Panels of cell lines such as the NCI-60 have long been used to test drug candidates for their ability to inhibit proliferation. Predictive models of in vitro drug sensitivity have previously been constructed using gene expression signatures generated from gene expression microarrays. These statistical models allow the prediction of drug response for cell lines not in the original NCI-60. We improve on existing techniques by developing a novel multistep algorithm that builds regression models of drug response using Random Forest, an ensemble approach based on classification and regression trees (CART). RESULTS: This method proved successful in predicting drug response for both a panel of 19 Breast Cancer and 7 Glioma cell lines, outperformed other methods based on differential gene expression, and has general utility for any application that seeks to relate gene expression data to a continuous output variable. Implementation: Software was written in the R language and will be available together with associated gene expression and drug response data as the package ivDrug at http://r-forge.r-project.org. 相似文献
998.
Several microRNAs mediate the functions of p53 family members. Here we characterize miR-1246 as a new target of this family. In response to DNA damage, p53 induces the expression of miR-1246 which, in turn, reduces the level of DYRK1A, a Down syndrome-associated protein kinase. Knockdown of p53 has the opposite effect. Overexpression of miR-1246 reduces DYRK1A levels and leads to the nuclear retention of NFATc1, a protein substrate of DYRK1A, and the induction of apoptosis, whereas a miR-1246-specific inhibitor prevented the nuclear import of NFATc1. Together, these results indicate that p53 inhibits DYRK1A expression through the induction of miR-1246. 相似文献
999.
Won-Kyung Hong Chul-Ho Kim Sun-Yeon Heo Lian Hua Luo Baek-Rock Oh Dina Rairakhwada Jeong-Woo Seo 《Bioprocess and biosystems engineering》2011,34(2):231-236
Currently, 1,3-propanediol (1,3-PD) is an important chemical widely used in polymer production, but its availability is being
restricted owing to its expensive chemical synthesis. A methylotrophic yeast Hansenula polymorpha was engineered by expression of dhaB1, dhaB2, dhaB3, dhaB
RA1
and dhaB
RA2
encoding glycerol dehydratase complex and dhaT encoding 1,3-PD oxidoreductase from Klebsiella pneumoniae under direction of promoter of glyceraldehyde-3 phosphate dehydrogenase (GAPDH). The engineered recombinant yeast strain
can produce 1,3-PD from glucose (2.4 g L−1) as well as glycerol (0.8 g L−1), which might lead to a safe and cost-effective method for industrial production of 1,3-PD from various biomass resources. 相似文献
1000.
目的:探讨黄芪皂苷Ⅳ对大鼠心肌缺血/再灌注损伤的保护作用及抗凋亡作用。方法:研究黄芪皂苷Ⅳ对大鼠收缩压和舒张压的作用;建立大鼠心肌缺血/再灌注模型,在缺血前给予黄芪皂苷Ⅳ处理,观察心律失常的改变,测定血液中乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)和丙二醛(MDA)的变化,检测计算凋亡心肌细胞百分比及对P-STAT1、P-STAT3蛋白表达的调控作用。结果:黄芪皂苷Ⅳ可降低大鼠收缩压和舒张压,心肌缺血/再灌注前,预先给予黄芪皂苷Ⅳ有抗心律失常作用,降低血液中LDH和MDA含量,提高SOD活性,降低凋亡心肌细胞百分比,显著增加P-STAT1蛋白表达而同时降低P-STAT3蛋白表达。结论:黄芪皂苷Ⅳ对心肌缺血/再灌注损伤具有一定的保护作用,减少心肌细胞凋亡,其机制可能与抑制P—STAT1,诱导P—STAT3表达有关。 相似文献