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81.
Hirata H Yamamura I Yasuda K Kobayashi A Tada N Suzuki M Hirayoshi K Hosokawa N Nagata K 《The Journal of biological chemistry》1999,274(50):35703-35710
HSP47 is a collagen-binding heat shock protein and is assumed to act as a molecular chaperone in the biosynthesis and secretion of procollagen. As the synthesis of HSP47 is closely correlated with that of collagen in various cell lines and tissues, we performed a promoter/reporter assay using HSP47-producing and nonproducing cells. 280 base pairs (bp(s)) of upstream promoter were shown to be necessary for the basal expression but not to be enough for the cell type-specific expression. When the first and the second introns were introduced downstream of this 280-bp region, marked up-regulation of the reporter activity was observed in HSP47-producing cells but not in nonproducing cells. This was confirmed in transgenic mice by staining the lacZ gene product under the control of the 280-bp upstream promoter and the introns. Staining was observed in skin, chondrocytes, precursor of bone, and other HSP47/collagen-producing tissues. A putative Sp1-binding site at -210 bp in the promoter, to which Sp3 and an unidentified protein bind, was shown to be responsible for this up-regulation when combined with the introns. However no difference in the binding to this probe was observed between HSP47-producing and nonproducing cells. The responsible region for cell type-specific up-regulation was found to be located in a 500-bp segment in the first intron. On electrophoresis mobility shift assay using this 500-bp probe, specific DNA-protein complexes were only observed in HSP47-producing cell extracts. These results suggest that two separate elements are necessary for the cell type-specific expression of the hsp47 gene; one is a putative Sp1-binding site at -210 bp necessary for basal expression, and the other is a 500-bp region within the first intron, required for cell type-specific expression. 相似文献
82.
Tanaka Y Kasai M Taneichi M Naito S Kato H Mori M Nishida M Maekawa N Yamamura H Komuro K Uchida T 《Bioconjugate chemistry》2004,15(1):35-40
We previously reported that liposomes having differential lipid components displayed differential adjuvant effects when antigen was coupled with liposomes via glutaraldehyde. In the present study, antigen-liposome conjugates prepared using liposomes having differential lipid components were added to the macrophage culture, and phagocytosis and the antigen digest of liposome-coupled antigen by macrophages were then investigated. Antigen presentation by macrophages to an antigen-specific T-cell clone was further investigated using the same conjugates. Antigen-liposome conjugates which induced higher levels of antibody production in vivo were recognized more often, and the liposome-coupled antigen was digested to a greater degree by macrophages than antigen-liposome conjugates which induced lower levels of antibody production. These results correlated closely with those regarding antigen presentation by macrophages; when antigen was coupled to liposomes showing higher adjuvant effect, macrophages cocultured with antigen-liposome conjugates activated antigen-specific T-cells at a higher degree. The concentration of OVA in the macrophage culture added as antigen-liposome conjugates was approximately 32 microg/mL. However, the extent of T-cell activation was almost equal to that when 800 microg/mL of soluble OVA was added to the culture. The results of the present study demonstrated that the adjuvant activity of liposomes observed primary in vivo correlated closely with the recognition of antigen-liposome conjugates and antigen presentation of liposome-coupled antigen by macrophages, suggesting that the adjuvant effects of liposomes are exerted at the beginning of the immune response, i.e., recognition of antigen by antigen-presenting cells. 相似文献
83.
Kurosaka Y Ishida Y Yamamura E Takase H Otani T Kumon H 《Microbiology and immunology》2001,45(1):9-15
This study established a rat model of foreign body-associated urinary tract infection. A spiral polyethylene tube (PT) was placed transurethrally into the bladder without surgical manipulation, followed by transurethral inoculation with Pseudomonas aeruginosa. The persistence of P. aeruginosa in the kidneys and bladder was significantly enhanced by placement of the PT, whereas the bacteria were eliminated rapidly from the urinary tract in the animals without the PT. Scanning electron microscopy revealed a thick biofilm on the surface of the PT from the early stage of infection. Histopathologically, acute pyelonephritis was followed by chronic renal inflammation as well as continuous and sporadic polymorphonuclear leukocyte accumulation and hemorrhage in the pelvis and adjacent tissues, suggesting continuous ascending introduction of the bacteria from the biofilm adhering to the PT. We believe our model simulates the pathophysiology of foreign body-associated urinary tract infection characterized by biofilm formation on the surface of a foreign body. 相似文献
84.
barS1, a gene for biosynthesis of a gamma-butyrolactone autoregulator,a microbial signaling molecule eliciting antibiotic production in Streptomyces species 下载免费PDF全文
From Streptomyces virginiae, in which production of streptogramin antibiotic virginiamycin M(1) and S is tightly regulated by a low-molecular-weight Streptomyces hormone called virginiae butanolide (VB), which is a member of the gamma-butyrolactone autoregulators, the hormone biosynthetic gene (barS1) was cloned and characterized by heterologous expression in Escherichia coli and by gene disruption in S. virginiae. The barS1 gene (a 774-bp open reading frame encoding a 257-amino-acid protein [M(r), 27,095]) is situated in the 10-kb regulator island surrounding the VB-specific receptor gene, barA. The deduced BarS1 protein is weakly homologous to beta-ketoacyl-acyl carrier protein/coenzyme A reductase and belongs to the superfamily of short-chain alcohol dehydrogenase. The function of the BarS1 protein in VB biosynthesis was confirmed by BarS1-dependent in vitro conversion of 6-dehydro-VB-A to VB-A, the last catalytic step in VB biosynthesis. Of the four possible enantiomeric products from racemic 6-dehydro-VB-A as a substrate, only the natural enantiomer of (2R,3R,6S)-VB-A was produced by the purified recombinant BarS1 (rBarS1), indicating that rBarS1 is the stereospecific reductase recognizing (3R)-isomer as a substrate and reducing it stereospecifically to the (6S) product. In the DeltabarS1 mutant created by homologous recombination, the production of VB as well as the production of virginiamycin was lost. The production of virginiamycin by the DeltabarS1 mutant was fully recovered by the external addition of VB to the culture, which indicates that the barS1 gene is essential in the biosynthesis of the autoregulator VBs in S. virginiae and that the failure of virginiamycin production was a result of the loss of VB production. 相似文献
85.
The inhibitory effect of Citrus junos peel on plant growth using lettuce (Lactuca sativa L.) as a bioassay material was investigated, since the powder of the peel had been found to inhibit growth of weeds. Basic, neutral and acidic fractions were separated from the aqueous fraction obtained from the methanol extract of C. junos peel. All fractions inhibited the growth of lettuce seedlings, but by far the greatest inhibition was observed with the neutral fraction. Thus, the latter was further purified and an allelopathically active substance was isolated. The structure of the substance was determined from high-resolution MS and 1H and 13C NMR spectral data as abscisic acid-beta-D-glucopyranosyl ester (ABA-GE). ABA-GE inhibited hypocotyl and root growth of lettuce seedlings at concentrations greater than 0.3 microM, and the concentrations for 50% inhibition of hypocotyl and root growth were 2.3 and 1.4 microM, respectively. The effectiveness of ABA-GE on inhibition of growth and the occurrence of ABA-GE in the peel itself suggested that ABA-GE may play an important role in the allelopathic potential of C. junos peel. The peel may be potentially useful for weed management in a field setting. 相似文献
86.
87.
Sakaguchi T Kitagawa K Ando T Murakami Y Morita Y Yamamura A Yokoyama K Tamiya E 《Biosensors & bioelectronics》2003,19(2):115-121
A biochemical oxygen demand (BOD) sensing system based on bacterial luminescence from recombinant Escherichia coli containing lux A-E genes from Vibrio fischeri has been developed. It was possible to use frozen cells of luminescent recombinants of E. coli as the bacterial reagents for measurement. Steady bioluminescence was observed during the incubation time between 90 and 150 min in the presence of a sole carbon source such as glucose, acetate, L-glutamate and BOD standard solution (GGA solution). This disposable bacterial reagent was applied to measure and detect organic pollution due to biodegradable substances in various wastewaters. The obtained values of this study showed a similar correlation with that of the conventional method for BOD determination (BOD5). Bacterial luminescence that was visualized with an imaging system using a charge coupled device (CCD) camera and a photomulti-counter demonstrated that this method could also be used for multi-sample detection of organic pollution due to biodegradable substances by using a microtiter plate. These results suggested for successful achievement of high-though-put detection of BOD in practical. 相似文献
88.
Critical role of Caenorhabditis elegans homologs of Cds1 (Chk2)-related kinases in meiotic recombination 下载免费PDF全文
Oishi I Iwai K Kagohashi Y Fujimoto H Kariya K Kataoka T Sawa H Okano H Otani H Yamamura H Minami Y 《Molecular and cellular biology》2001,21(4):1329-1335
Although chromosomal segregation at meiosis I is the critical process for genetic reassortment and inheritance, little is known about molecules involved in this process in metazoa. Here we show by utilizing double-stranded RNA (dsRNA)-mediated genetic interference that novel protein kinases (Ce-CDS-1 and Ce-CDS-2) related to Cds1 (Chk2) play an essential role in meiotic recombination in Caenorhabditis elegans. Injection of dsRNA into adult animals resulted in the inhibition of meiotic crossing over and induced the loss of chiasmata at diakinesis in oocytes of F(1) animals. However, electron microscopic analysis revealed that synaptonemal complex formation in pachytene nuclei of the same progeny of injected animals appeared to be normal. Thus, Ce-CDS-1 and Ce-CDS-2 are the first example of Cds1-related kinases that are required for meiotic recombination in multicellular organisms. 相似文献
89.
Miyagi N Sato K Rong Y Yamamura S Katagiri H Kobayashi K Iwata H 《Bioelectromagnetics》2000,21(2):112-121
After pulsed exposure of Dunn osteosarcoma cells (nonresistant cells) to Adriamycin (ADR) at increasing concentrations and single-cell cloning of surviving cells, ADR-resistant cells were obtained. These resistant cells expressed P-glycoprotein and had resistance more than 10 times that of their nonresistant parent cells. Compared to the nonresistant cells not exposed to pulsing electromagnetic fields (PEMF) in ADR-free medium, their growth rates at ADR concentrations of 0.01 and 0.02 micrograms/ml, which were below IC50, were 83.0% and 61.8%, respectively. On the other hand, in the nonresistant cells exposed to PEMF (repetition frequency, 10 Hz; rise time, 25 microsec, peak magnetic field intensity, 0.4-0.8 mT), the growth rate was 111.9% in ADR-free medium, 95.5% at an ADR concentration of 0.01 micrograms/ml, and 92.2% at an ADR concentration of 0.02 micrograms/ml. This promotion of growth by PEMF is considered to be a result of mobilization of cells in the non-proliferative period of the cell cycle due to exposure to PEMF. However, at ADR concentrations above the IC50, the growth rate tended to decrease in the cells not exposed to PEMF. This may be caused by an increase in cells sensitive to ADR resulting from mobilization of cells in the non-proliferative period to the cell cycle. The growth rate in the resistant cells exposed to PEMF was significantly lower than that in the non-exposed resistant cells at all ADR concentrations, including ADR-free culture (P=0.0114). Therefore, this study suggests that PEMF promotes the growth of undifferentiated cells but progressively suppresses the growth of more differentiated cells, i.e., PEMF controls cell growth depending on the degree of cell differentiation. This study also shows the potentiality of PEMF as an adjunctive treatment method for malignant tumors. 相似文献
90.
Tsuchida S Yanagi S Inatome R Ding J Hermann P Tsujimura T Matsui N Yamamura H 《Journal of biochemistry》2000,127(2):321-327
Syk protein-tyrosine kinase (PTK) has been implicated in a variety of hematopoietic cell responses including immunoreceptor signaling. However, so far, there has been no evidence of the expression of Syk or Syk-related PTK in non-hematopoietic tissues. In this study, we have purified from blood cell-depleted rat liver a 72-kDa cytoplasmic PTK which shows cross-reactivity with anti-Syk antibody. Partial amino acid sequence analysis revealed that this 72-kDa PTK is identical to Syk. Immunohistochemical and RT-PCR analyses demonstrated that Syk is expressed in human hepatocytes and two rat liver-derived cell lines, JTC-27 and RLC-16. Furthermore, Syk is significantly tyrosine-phosphorylated in response to angiotensin II in JTC-27 cells, and angiotensin II-induced MAP kinase activation is blocked by the treatment of cells with a Syk-selective inhibitor, piceatannol. These results suggest that Syk plays an important role in signaling events of hepatocytes, such as signaling steps leading to MAP kinase activation by G-protein-coupled receptors. This is the first report of the expression of Syk in non-hematopoietic tissue. 相似文献