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991.
Heat shock protein 27 (HSP27), an intracellular molecular chaperone, is involved in the pathogenesis of cancer by promoting both tumor cell proliferation and resistance to therapy. HSP27 is also present in the circulation and circulating HSP27 (sHSP27) can elicit an autoimmune response with production of antibodies. Levels of sHSP27 are enhanced in patients with hepatocellular carcinoma (HCC); it is, however, unknown whether changes in HSP27 antibody levels occur in patients with HCC and can be exploited as a circulating biomarker of HCC. Our aim was to assess the potential association between newly diagnosed HCC and serum anti-HSP27 antibody levels. In this cross-sectional study, anti-HSP27 antibody levels were measured in serum samples from 71 HCC patients, 80 subjects with chronic liver disease, and 38 control subjects by immunoenzymatic assay. Anti-HSP27 antibody levels did not differ significantly among groups. However, in patients with chronic active hepatitis/cirrhosis, anti-HSP27 levels were significantly higher in subjects with a positive history of alcoholism (p = 0.03). Our data do not support the hypothesis that anti-HSP27 antibody levels may help identify patients with HCC among subjects with chronic liver disease. However, our finding that alcohol-related liver disease is associated with higher anti-HSP27 levels is novel and deserves further investigations.  相似文献   
992.
C反应蛋白(C-reaction protein,CRP)是反映机体炎症的有效标志物,早期检测是判断炎症相关疾病的关键,因此,研制CRP新型检测制剂具有重要意义。利用噬菌体表面展示技术对CRP特异性亲和配体进行了筛选,采用固相肽合成技术对目标配体进行了合成,并经生物标记、高效液相色谱法(high performance liquid chromatography,HPLC)分析及质谱(mass spectrometry,MS)鉴定,成功制得检测CRP的荧光探针。经3轮筛选、ELISA检测、重组噬菌体测序及序列比对后得到1个目标配体肽:S-P-H-N-R-S-N-L-V-Q-E-L;经肽合成及生物标记获得1种CRP荧光探针:FITC-(Acp)-S-P-H-N-R-SN-L-V-Q-E-L。研究结果为CRP的有效检测提供了一种新型制剂。  相似文献   
993.
The human cardiovascular system has adapted to function optimally in Earth''s 1G gravity, and microgravity conditions cause myocardial abnormalities, including atrophy and dysfunction. However, the underlying mechanisms linking microgravity and cardiac anomalies are incompletely understood. In this study, we investigated whether and how calpain activation promotes myocardial abnormalities under simulated microgravity conditions. Simulated microgravity was induced by tail suspension in mice with cardiomyocyte-specific deletion of Capns1, which disrupts activity and stability of calpain-1 and calpain-2, and their WT littermates. Tail suspension time-dependently reduced cardiomyocyte size, heart weight, and myocardial function in WT mice, and these changes were accompanied by calpain activation, NADPH oxidase activation, and oxidative stress in heart tissues. The effects of tail suspension were attenuated by deletion of Capns1. Notably, the protective effects of Capns1 deletion were associated with the prevention of phosphorylation of Ser-345 on p47phox and attenuation of ERK1/2 and p38 activation in hearts of tail-suspended mice. Using a rotary cell culture system, we simulated microgravity in cultured neonatal mouse cardiomyocytes and observed decreased total protein/DNA ratio and induced calpain activation, phosphorylation of Ser-345 on p47phox, and activation of ERK1/2 and p38, all of which were prevented by calpain inhibitor-III. Furthermore, inhibition of ERK1/2 or p38 attenuated phosphorylation of Ser-345 on p47phox in cardiomyocytes under simulated microgravity. This study demonstrates for the first time that calpain promotes NADPH oxidase activation and myocardial abnormalities under microgravity by facilitating p47phox phosphorylation via ERK1/2 and p38 pathways. Thus, calpain inhibition may be an effective therapeutic approach to reduce microgravity-induced myocardial abnormalities.  相似文献   
994.
995.
Some studies have shown that transplanted fat tissues usually cannot survive for long if adipose-derived stem cells (ADSCs) are removed from the tissues in advance. It is more meaningful to explore the mechanism mediating survival and differentiation of ADSCs in the transplanted microenvironment. AMP-activated protein kinase (AMPK) has been shown to be one of the energy receptors that regulate many aspects of cellular metabolism. AMPK activation has been implicated in models of adult ischemic injury, but the mechanism and the regulating effects of AMPK on survival and adipogenesis of transplanted ADSCs are still little known. In this study, we simulated the transplanted microenvironment using oxygen-glucose deprivation (OGD) to test the survival and adipogenesis of ADSCs. We found that OGD treatment triggered significant apoptosis and promoted autophagy. Simultaneously, OGD hindered the differentiation of ADSCs into mature adipocytes. After inhibiting AMPK, the OGD-induced apoptosis rate increased but autophagy was inhibited. The adipogenesis level also decreased. To show that the effects of AMPK on apoptosis and adipogenesis were autophagy-dependent, we pre-inhibited or pre-promoted autophagy with siATG7 or rapamycin while blocking AMPK. We found that inhibiting or improving autophagy exacerbated or alleviated the role of AMPK prohibition in apoptosis and adipogenesis. Furthermore, we showed that AMPK inhibition significantly lowered ULK1 activity but promoted mTOR activity, so that to inhibit autophagy. Our study shows that AMPK plays a protective role in maintaining survival and adipogenesis of OGD-challenged ADSCs partly by positively regulating autophagy. AMPK positively regulates autophagy by inhibiting mTOR but promoting ULK1 activity in OGD condition.  相似文献   
996.
Antizyme (Az) is a highly conserved key regulatory protein bearing a major role in regulating polyamine levels in the cell. It has the ability to bind and inhibit ornithine decarboxylase (ODC), targeting it for degradation. Az inhibitor (AzI) impairs the activity of Az. In this study, we mapped the binding sites of ODC and AzI on Az using Ala scan mutagenesis and generated models of the two complexes by constrained computational docking. In order to scan a large number of mutants in a short time, we developed a workflow combining high-throughput mutagenesis, small-scale parallel partial purification of His-tagged proteins and their immobilization on a tris-nitrilotriacetic-acid-coated surface plasmon resonance chip. This combination of techniques resulted in a significant reduction in time for production and measurement of large numbers of mutant proteins. The data-driven docking results suggest that both proteins occupy the same binding site on Az, with Az binding within a large groove in AzI and ODC. However, single-mutant data provide information concerning the location of the binding sites only, not on their relative orientations. Therefore, we generated a large number of double-mutant cycles between residues on Az and ODC and used the resulting interaction energies to restrict docking. The model of the complex is well defined and accounts for the mutant data generated here, and previously determined biochemical data for this system. Insights on the structure and function of the complexes, as well as general aspects of the method, are discussed.  相似文献   
997.

Background

Many proteins have LRR (leucine-rich repeat) units interrupted by non-LRRs which we call IR (non-LRR island region).

Methods

We identified proteins containing LRR@IRs (LRRs having IR) by using a new method and then analyzed their natures and distributions.

Results

LRR@IR proteins were found in over two hundred proteins from prokaryotes and from eukaryotes. These are divided into twenty-one different protein families. The IRs occur one to four times in LRR regions and range in length from 5 to 11,265 residues. The IR lengths in Fungi adenylate cyclases (acys) range from 5 to 116 residues; there are 22 LRR repeats. The IRs in Leishmania proteophosphoglycans (ppgs) vary from 105 to 11,265 residues. These results indicate that the IRs evolved rapidly. A group of LRR@IR proteins—LRRC17, chondroadherin-like protein, ppgs, and four Pseudomonas proteins—have a super motif consisting of an LRR block and its adjacent LRR@IR region. This indicates that the entire super motif experienced duplication. The sequence analysis of IRs offers functional similarity in some LRR@IR protein families.

General significance

This study suggests that various IRs and super motifs provide a great variety of structures and functions for LRRs.  相似文献   
998.
To gain further insights into the relationship between plasma phospholipid transfer protein (PLTP) and lipoprotein particles, PLTP mass and phospholipid transfer activity were measured, and their associations with the level and size of lipoprotein particles examined in 39 healthy adult subjects. No bivariate correlation was observed between PLTP activity and mass. PLTP activity was positively associated with cholesterol, triglyceride, apo B and VLDL particle level (rs = 0.40–0.56, p ≤ 0.01) while PLTP mass was positively associated with HDL-C, large HDL particles, and mean LDL and HDL particle sizes (rs = 0.44–0.52, p < 0.01). Importantly, plasma PLTP specific activity (SA) was significantly associated with specific lipoprotein classes, positively with VLDL, IDL, and small LDL particles (rs = 0.42–0.62, p ≤ 0.01) and inversely with large LDL, large HDL, and mean LDL and HDL particle size (rs = − 0.42 to − 0.70, p ≤ 0.01). After controlling for triglyceride levels, the correlation between PLTP mass or SA and HDL size remained significant. In linear models, HDL size explained 45% of the variability of plasma PLTP SA while triglyceride explained 34% of the PLTP activity. Thus, in healthy adults a significant relationship exists between HDL size and plasma PLTP SA (rs = − 0.70), implying that HDL particle size may modulate PLTP SA in the vascular compartment.  相似文献   
999.
Integration of living cells with novel microdevices requires the development of innovative technologies for manipulating cells. Chemical surface patterning has been proven as an effective method to control the attachment and growth of diverse cell populations. Patterning polyelectrolyte multilayers through the combination of layer‐by‐layer self‐assembly technique and photolithography offer a simple, versatile, and silicon compatible approach that overcomes chemical surface patterning limitations, such as short‐term stability and low‐protein adsorption resistance. In this study, direct photolithographic patterning of two types of multilayers, PAA (poly acrylic acid)/PAAm (poly acryl amide) and PAA/PAH (poly allyl amine hydrochloride), were developed to pattern mammalian neuronal, skeletal, and cardiac muscle cells. For all studied cell types, PAA/PAAm multilayers behaved as a cytophobic surface, completely preventing cell attachment. In contrast, PAA/PAH multilayers have shown a cell‐selective behavior, promoting the attachment and growth of neuronal cells (embryonic rat hippocampal and NG108‐15 cells) to a greater extent, while providing little attachment for neonatal rat cardiac and skeletal muscle cells (C2C12 cell line). PAA/PAAm multilayer cellular patterns have also shown a remarkable protein adsorption resistance. Protein adsorption protocols commonly used for surface treatment in cell culture did not compromise the cell attachment inhibiting feature of the PAA/PAAm multilayer patterns. The combination of polyelectrolyte multilayer patterns with different adsorbed proteins could expand the applicability of this technology to cell types that require specific proteins either on the surface or in the medium for attachment or differentiation, and could not be patterned using the traditional methods. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009  相似文献   
1000.
Amyotrophic lateral sclerosis (ALS) is an adult‐onset neurodegenerative disorder characterized by selective loss of motor neurons (MNs). Twenty percent of familial ALS cases are associated with mutations in Cu2+/Zn2+ superoxide dismutase (SOD1). To specifically understand the cellular mechanisms underlying mutant SOD1 toxicity, we have established an in vitro model of ALS using rat primary MN cultures transfected with an adenoviral vector encoding a mutant SOD1, G93A‐SOD1. Transfected cells undergo axonal degeneration and alterations in biochemical responses characteristic of cell death such as activation of caspase‐3. Vascular endothelial growth factor (VEGF) is an angiogenic and neuroprotective growth factor that can increase axonal outgrowth, block neuronal apoptosis, and promote neurogenesis. Decreased VEGF gene expression in mice results in a phenotype similar to that seen in patients with ALS, thus linking loss of VEGF to the pathogenesis of MN degeneration. Decreased neurotrophic signals prior to and during disease progression may increase MN susceptibility to mutant SOD1‐induced toxicity. In this study, we demonstrate a decrease in VEGF and VEGFR2 levels in the spinal cord of G93A‐SOD1 ALS mice. Furthermore, in isolated MN cultures, VEGF alleviates the effects of G93A‐SOD1 toxicity and neuroprotection involves phosphatidylinositol 3‐kinase/protein kinase B (PI3K/Akt) signaling. Overall, these studies validate the usefulness of VEGF as a potential therapeutic factor for the treatment of ALS and give valuable insight into the responsible signaling pathways and mechanisms involved. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009  相似文献   
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