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951.
A flow injection chemiluminescence method is described for the determination of subnanomolar concentrations of vanadium in environmental water samples. The procedure is based on the oxidation of luminol in the presence of dissolved oxygen catalyzed by vanadium(IV). Vanadium(V) reduction and preconcentration of vanadium(IV) was carried out using in‐line silver reductor and 8‐hydroxyquinoline chelating columns at pH 3.15, respectively. The calibration graph for vanadium(IV) was linear in the concentration range of 0.025–10 µg/L with relative standard deviation in the range of 0.4–5.58%. The detection limit (3s blank) was 3.8 × 10?3 µg/L without preconcentration; when the vanadium(IV) was preconcentrated with an 8‐HQ column for 1 min (2.0 mL of sample loaded), the detection limit of 5.1 × 10?4 µg/L was achieved. One analytical cycle can be completed in 2.0 min. The analysis of certified reference materials (CASS‐4, NASS‐5 and SLRS‐4) by the proposed method showed good agreement with the certified values. The method was successfully applied to the determination of total dissolved vanadium in environmental water samples. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
952.
953.
Colletotrichum gloeosporioides is a facultative plant pathogen: it can live as a saprophyte on dead organic matter or as a pathogen on a host plant. Different patterns of conidial germination have been recognized under saprophytic and pathogenic conditions, which also determine later development. Here we describe the role of CgRac1 in regulating pathogenic germination. The hallmark of pathogenic germination is unilateral formation of a single germ tube following the first cell division. However, transgenic strains expressing a constitutively active CgRac1 (CA-CgRac1) displayed simultaneous formation of two germ tubes, with nuclei continuing to divide in both cells after the first cell division. CA-CgRac1 also caused various other abnormalities, including difficulties in establishing and maintaining cell polarity, reduced conidial and hyphal adhesion, and formation of immature appressoria. Consequently, CA-CgRac1 isolates were completely nonpathogenic. Localization studies with cyan fluorescent protein (CFP)-CgRac1 fusion protein showed that the CgRac1 protein is abundant in conidia and in hyphal tips. Although the CFP signal was equally distributed in both cells of a germinating conidium, reactive oxygen species accumulated only in the cell that produced a germ tube, indicating that CgRac1 was active only in the germinating cell. Collectively, our results show that CgRac1 is a major regulator of asymmetric development and that it is involved in the regulation of both morphogenesis and nuclear division. Modification of CgRac1 activity disrupts the morphogenetic program and prevents fungal infection. 相似文献
954.
Allografting and autografting of osteochondral tissues is a promising strategy to treat articular cartilage lesions in damaged joints. We developed a new model of fresh osteochondral allografting using the entire rabbit trochlea. The objective of the current study was to demonstrate that this model would achieve reproducible graft-host healing and maintain normal articular cartilage histologic, immunolocalization, and biochemical characteristics after transplantation under diverse storage and transplantation conditions. New Zealand white (n = 8) and Dutch belted (n = 8) rabbits underwent a 2-stage transplantation operation using osteochondral grafts that had been stored for 2 or 4 wk. Trochlear grafts harvested from the left knee were transplanted to the right knee as either autografts or allografts. Grafts were fixed with 22-gauge steel wire or 3-0 nylon suture. Rabbits were euthanized for evaluation at 1, 2, 4, 6, and 12 wk after transplantation. All grafts that remained in vivo for at least 4 wk demonstrated 100% interface healing by microCT. Trabecular bridging was present at the host-graft interface starting at 2 wk after transplantation, with no significant difference in cartilage histology between the various groups. The combined histology scores indicated minimal evidence of osteoarthritis. Immunostaining revealed that superficial zone protein was localized at the surface of all transplants. The rabbit trochlear model met our criteria for a successful model in regard to the ease of the procedure, low rate of surgical complications, relatively large articular cartilage surface area, and amount of host-graft bone interface available for analysis. 相似文献
955.
Nasir F Iqbal Z Khan A Ahmad L Shah Y Khan AZ Khan JA Khan S 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(30):3434-3443
A novel HPLC-UV method was developed for the simultaneous determination of timolol (TM), rosuvastatin (RST), and diclofenac sodium (DS) in pharmaceuticals, human plasma and aqueous humor using naproxen sodium as internal standard (IS). The target compounds were analyzed on Hypersil BDS C(18) column (250 mm × 4.6 mm, 5 μm), applying 0.2% triethylamine (TEA) and acetonitrile (ACN) (40:60, v/v), in isocratic mode as mobile phase, pH 2.75 adjusted with 85% phosphoric acid at a flow rate of 1 ml/min. The column oven temperature was kept at 45°C and the peak response was monitored at 284 nm after injecting a 50 μl sample into HPLC system. The direct liquid-liquid extraction procedure was applied to human plasma and bovine aqueous humor samples using mobile phase as an extraction solvent after deproteination with methanol. The different HPLC experimental parameters were optimized and the method was validated according to standard guidelines. The recoveries of the suggested method in human plasma were 98.72, 96.04, and 95.14%, for TM, RST, and DS, while in aqueous humor were 94.99, and 98.23%, for TM, and DS, respectively. The LOD values were found to be 0.800, 0.500, and 0.250 ng/ml, for TM, RST, and DS, respectively, while their respective LOQ values were 2.00, 1.50, and 1.00 ng/ml. The co-efficient of variation (CV) were in the range of 0.1492-1.1729% and 1.0516-4.0104%, for intra-day and inter-day studies, respectively. The method was found accurate in human plasma and bovine aqueous humor and will be applied for the quantification of these compounds in plasma, and aqueous humor samples using animal models and in pharmaceuticals. 相似文献
956.
957.
Maude RJ Hoque G Hasan MU Sayeed A Akter S Samad R Alam B Yunus EB Rahman R Rahman W Chowdhury R Seal T Charunwatthana P Chang CC White NJ Faiz MA Day NP Dondorp AM Hossain A 《PloS one》2011,6(11):e27273
Background
Early start of enteral feeding is an established treatment strategy in intubated patients in intensive care since it reduces invasive bacterial infections and length of hospital stay. There is equipoise whether early enteral feeding is also beneficial in non-intubated patients with cerebral malaria in resource poor settings. We hypothesized that the risk of aspiration pneumonia might outweigh the potential benefits of earlier recovery and prevention of hypoglycaemia.Method and Findings
A randomized trial of early (day of admission) versus late (after 60 hours in adults or 36 hours in children) start of enteral feeding was undertaken in patients with cerebral malaria in Chittagong, Bangladesh from May 2008 to August 2009. The primary outcome measures were incidence of aspiration pneumonia, hypoglycaemia and coma recovery time. The trial was terminated after inclusion of 56 patients because of a high incidence of aspiration pneumonia in the early feeding group (9/27 (33%)), compared to the late feeding group (0/29 (0%)), p = 0.001). One patient in the late feeding group, and none in the early group, had hypoglycaemia during admission. There was no significant difference in overall mortality (9/27 (33%) vs 6/29 (21%), p = 0.370), but mortality was 5/9 (56%) in patients with aspiration pneumonia.Conclusions
In conclusion, early start of enteral feeding is detrimental in non-intubated patients with cerebral malaria in many resource-poor settings. Evidence gathered in resource rich settings is not necessarily transferable to resource-poor settings.Trial Registration
Controlled-Trials.com ISRCTN57488577 相似文献958.
Allard M Oger R Vignard V Percier JM Fregni G Périer A Caignard A Charreau B Bernardeau K Khammari A Dréno B Gervois N 《PloS one》2011,6(6):e21118
Background
Tumor-derived soluble factors, including soluble HLA molecules, can contribute to cancer immune escape and therefore impact on clinical course of malignant diseases. We previously reported that melanoma cells produce, in vitro, soluble forms of the non-classical MHC class I molecule HLA-E (sHLA-E). In order to investigate sHLA-E production by various tumors and to address its potential value as a tumor-associated marker, we developed a specific ELISA for the quantification of sHLA-E in biological fluids.Methodology/Principal Findings
We developed a sHLA-E specific and sensitive ELISA and we showed that serum sHLA-E levels were significantly elevated (P<0.01) in melanoma patients (n = 127), compared with healthy donors (n = 94). sHLA-E was also detected in the culture supernatants of a wide variety of tumor cell lines (n = 98) including melanomas, kidney, colorectal and breast cancers. Cytokines regulation of sHLA-E production by tumor cells was also carried out. IFN-γ, IFN-α and TNF-α were found to upregulate sHLA-E production by tumor cells.Conclusions/Significance
In view of the broad tumor tissue release of HLA-E and its up-regulation by inflammatory cytokines, sHLA-E should be studied for its involvement in immune responses against tumors. Interestingly, our results demonstrated a positive association between the presence of serum sHLA-E and melanoma. Therefore, the determination of sHLA-E levels, using ELISA approach, may be investigated as a clinical marker in cancer patients. 相似文献959.
Allelic frequency and genotypes of prion protein at codon 136 and 171 in Iranian Ghezel sheep breeds
Siamak Salami Reza Ashrafi Zadeh Mir Davood Omrani Fatemeh Ramezani Amir Amniattalab 《朊病毒》2011,5(3):228-231
PrP genotypes at codons 136 and 171 in 120 Iranian Ghezel sheep breeds were studied using allele-specific PCR amplification and compared with the well-known sheep breeds in North America, the United States and Europe. The frequency of V allele and VV genotype at codon 136 of Ghezel sheep breed was significantly lower than AA and AV. At codon 171, the frequency of allele H was significantly lower than Q and R. Despite the similarities of PrP genotypes at codons 136 and 171 between Iranian Ghezel sheep breeds and some of the studied breeds, significant differences were found with others. Planning of effective breeding control and successful eradication of susceptible genotypes in Iranian Ghezel sheep breeds will not be possible unless the susceptibility of various genotypes in Ghezel sheep breeds to natural or experimental scrapie has been elucidated.Key words: scrapie, Ghezel sheep breed, PrP genotyping, allele specific amplification, codon 136, codon 171Scrapie was first described in England in 1732,1 and it is an infectious neurodegenerative fatal disease of sheep and goats belonging to the group of transmissible subacute spongiform encephalopathies (TSEs), along with bovine spongiform encephalopathy (BSE), chronic wasting disease and Creutzfeldt-Jakob disease.2,3 The term prion, proteinaceous infectious particles, coined by Stanley B. Prusiner, was introduced, and he presents the idea that the causal agent is a protein.4 Prion proteins are discovered in two forms, the wild-type form (PrPc) and the mutant form (PrPSc).5 Although scrapie is an infectious disease, the susceptibility of sheep is influenced by genotypes of the prion protein (PrP) gene.2,6 Researchers have found that the PrP allelic variant alanine/arginine/arginine (ARR) at codons 136, 154 and 171 is associated with resistance to scrapie in several breeds.7–14 Most of the sheep populations in the Near East and North African Region (84% of the total population of 255 million) are raised in Iran, Turkey, Pakistan, Sudan, Algeria, Morocco, Afghanistan, Syria and Somalia.15 In 2003, the Iranian sheep population was estimated at 54,000,000 head. The Ghezel sheep breed, which also is known as Kizil-Karaman, Mor-Karaman, Dugli, Erzurum, Chacra, Chagra, Chakra, Gesel, Gezel, Kazil, Khezel, Khizel, Kizil, Qezel, Qizil and Turkish Brown, originated in northwestern Iran and northeastern Turkey. By considering sheep breeds as one of the main sources of meat, dairy products and related products, a global screening attempt is started in different areas. In compliance with European Union Decision 2003/100/EC, each member state has introduced a breeding program to select for resistance to TSEs in sheep populations to increase the frequency of the ARR allele. A similar breeding program is established in United States and Canada. The Near East and North African Region still needs additional programs to help the global plan of eradication of scrapie-susceptible genotypes. The current study was the first to assess the geographical and molecular variation of codons 136 and 171 polymorphism between Iranian Ghezel sheep breed and well-known sheep breeds.Polymorphism at codon 136 is associated with susceptibility to scrapie in both experimental and natural models.10,11,13,16 17 and Austrian Carynthian sheep.18 Swiss White Alpine showed higher frequency of allele V at position 136 than Swiss Oxford Down, Swiss Black-Brown Mountain and Valais Blacknose.19 Comparison of polymorphism at codon 136 in the current study with some of other breeds (20 some flock of Hampshire sheep21 with current study, but the frequency of it is higher than that of some other breeds.
Open in a separate windowIt has been found that a polymorphism at codon 171 also is associated with susceptibility to experimental scrapie in Cheviot sheep16 and natural scrapie in Suffolk sheep.22 As shown in 23 They also found that different breeds show different predominant genotypes in ewes and rams.23 Different PrP genotypes were found at codon 171 in Austrian sheep breeds, but QQ has higher frequency than others.18 In some kinds of Swiss breeds, allelic frequencies of allele Q was higher than R.19 Distribution of prion protein codon 171 genotypes in Hampshire sheep revealed that different flocks shows different patterns.21 The frequency of PrP genotypes at codon 171 in Iranian Ghezel breeds was similar to some sheep breeds, like the Suffolk breed of Oklahoma sheep, but it was completely different from others (PrP genotypes at codon 172 Breed Allelic frequency Genotypes Reference Q R H RR QR QQ QH RH HH Iranian Iranian Ghezel breeds (n = 120) 55.00 43.33 1.67 23.33 36.67 36.67 0.00 3.33 0.00 Current study Oklahoma sheep (n = 334) De Silva, et al.20 Suffolk 40.95 59.05 0.00 37.07 43.97 18.97 0.00 0.00 0.00 Hampshire 51.89 48.11 0.00 21.70 52.83 25.47 0.00 0.00 0.00 Dorset 67.75 31.25 0.00 7.95 46.59 45.45 0.00 0.00 0.00 Montadale 62.96 37.04 0.00 14.81 44.44 40.74 0.00 0.00 0.00 Hampshire (n = 201) 72.14 26.60 1.26 5.00 42.00 50.00 2.00 1.00 0.00 Youngs, et al.21 German Sheep Breeds (n = 660) Kutzer, et al.28 Bleu du Maine 37.8 62.2 0.00 46.96 30.44 22.6 0.00 0.00 0.00 Friesian Milk S. 90.45 8.9 0.65 1.27 15.3 82.8 0.00 0.00 0.64 Nolana 42.3 57.8 0.00 36.62 42.26 21.13 0.00 0.00 0.00 Suffolk 68.4 27.6 4.0 16.1 21.84 55.17 4.6 1.15 1.15 Texel 55.35 29.7 14.9 12.56 26.83 36.36 11.25 7.36 5.63 Swiss Sheep (n = 200) Gmur, et al.19 Swiss Oxford Down 32.00 68.00 - - - - - - - Swiss Black-Brown M. 70.00 30.00 - - - - - - - Valais Blacknose 85.00 15.00 - - - - - - - Swiss White Alpine 27.00 73.00 - - - - - - - Austrian Sheep (n = 112) Sipos, et al.18 Tyrolean mountain sheep 74.30 25.80 0.00 2.90 45.70 51.40 0.00 0.00 0.00 Forest sheep 77.00 19.20 3.80 11.50 15.40 69.20 0.00 0.00 3.80 Tyrolean stone sheep 81.50 14.80 3.70 0.00 29.60 62.90 7.40 0.00 0.00 Carynthian sheep 72.80 23.00 4.20 4.20 41.70 13.00 8.40 0.00 0.00
Table 1
Comparison of PrP allelic and genotype frequencies at codon 136 in different breedsBreed | A (%) | V (%) | AA (%) | AV (%) | VV (%) | Reference |
Iranian Ghezel breeds (n = 120) | 77.50 | 22.5 | 65.00 | 25.00 | 10.00 | Current study |
Oklahoma sheep (n = 334) | De Silva, et al.27 | |||||
Suffolk | 99.24 | 0.76 | 98.48 | 1.52 | 0.00 | |
Hampshire | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Dorset | 92.6 | 7.94 | 87.30 | 9.52 | 3.17 | |
Montadale | 77.66 | 22.34 | 59.57 | 36.17 | 4.26 | |
Hampshire (n = 48) | 93.75 | 6.25 | 88.00 | 12.00 | 0.00 | Youngs, et al.21 |
German Sheep Breeds (n = 660) | 92.89 | 7.11 | 87.80 | 10.47 | 1.73 | Kutzer, et al.28 |
Bleu du Maine | 83.47 | 16.53 | 69.56 | 27.83 | 2.61 | |
Friesian Milk S. | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Nolana | 90.13 | 9.87 | 85.90 | 8.46 | 5.64 | |
Suffolk | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Texel | 90.87 | 9.13 | 82.16 | 17.41 | 0.43 | |
Swiss Sheep (n = 200) | 92.5 | 7.5 | Gmur, et al.19 | |||
Swiss Oxford Down | 93.00 | 7.00 | - | - | - | |
Swiss Black-Brown M. | 99.00 | 1.00 | - | - | - | |
Valais Blacknose | 100 | 0.00 | - | - | - | |
Swiss White Alpine | 88.00 | 22.00 | - | - | - | |
Austrian Sheep (n = 112) | 98.95 | 1.05 | 98.95 | 0.00 | 1.05 | Sipos, et al.18 |
Tyrolean mountain sheep | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Forest sheep | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Tyrolean stone sheep | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Carynthian sheep | 95.80 | 4.20 | 95.80 | 0.00 | 4.20 |