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921.
Taxonomic consensus is lacking on the Oxytropis arctica and O. campestris species complexes, two polyploid complexes found in the interior and arctic areas of Alaska. One classification has emphasized flower size, whereas flower color is considered a key diagnostic character in another classification. Our analyses of internal transcribed spacer (ITS) sequences and random amplified polymorphic DNA (RAPD) markers provided no support for either classification system. The trees generated from ITS sequences and the phenogram derived from RAPD markers suggest that most recognized taxa in the two complexes are probably polyphyletic, including O. arctica var. barnebyana, which is listed as threatened in Alaska. The only consistent pattern detected by both types of molecular markers was a geographic split dividing the northeastern arctic populations from most other populations (48.60-55.03% in AMOVA analyses). This genetic subdivision probably reflects a Pleistocene barrier formed by the northern coastal ice shield. Our molecular data, in conjunction with the previously reported variation of ploidy levels in these groups, suggest a scenario of recent and multiple origins of polyploidy. It is possible that most Alaskan populations of these two complexes are best referred to as a single taxonomic species despite morphological differentiation within the complexes.  相似文献   
922.
Some effects of perinatal hypoxia on pulmonary circulation are permanent. Since pulmonary vascular sensitivity to hypoxia in adults differs between sexes, we hypothesized that gender-based variability also exists in the long-term effects of perinatal hypoxia. Rats spent 1 wk before and 1 wk after birth in hypoxia (12% O2) and then lived in normoxia. When adult, females, but not males, with the perinatal experience of hypoxia had right ventricle hypertrophy. To assess the role of sex hormones, some rats were gonadectomized in ether anesthesia as newborns. Compared with intact, perinatally normoxic controls, muscularization of peripheral pulmonary vessels in adulthood was augmented in perinatally hypoxic, neonatally gonadectomized males (by 85%) and much more so in females (by 533%). Pulmonary artery pressure was elevated in perinatally hypoxic, neonatally gonadectomized females (24.4 +/- 1.7 mmHg) but not males (17.2 +/- 0.6 mmHg). Gonadectomy in adulthood had no effect. We conclude that female pulmonary circulation is more sensitive to late effects of perinatal hypoxia, and these effects are blunted by the presence of ovaries during maturation.  相似文献   
923.
Kostić I  Li S  Roy R 《Developmental biology》2003,263(2):242-252
The formation of a complex multicellular organism requires the precise specification of many diverse cell types at the correct time and position throughout development. This may be achieved by coordinating cell fate specification processes with progression through the cell cycle. Here, we show that the extra distal tip cells (DTCs) associated with the loss of cki-1, a Caenorhabditis elegans homologue of the cyclin-dependent kinase inhibitor p27, do not arise from duplications of pre-existing DTCs, but that they are formed from another cell type within the somatic gonad. Results from our laser microsurgery experiments suggest that the extra DTCs are caused by aberrant somatic gonadal precursor cell divisions in the absence of cki-1, resulting in abnormal daughter cell fates. cki-1(RNAi) animals also possess extra anchor cells and ectopic gonad arms with variable sheath cell numbers and positioning. In addition, cki-1(RNAi) animals display an endomitotic oocyte (Emo) phenotype. Our results uncover a novel role of this CKI in cell fate acquisition, either by directly influencing specification, or through a more conventional role in appropriately linking cell cycle phase with this process.  相似文献   
924.
The aim of this study was to confirm the role of screening by determining the percentage of clinically localized prostate cancer (stage A and B) in patients with prostate cancer detected on screening and in those presenting to urologic clinic for the symptoms of urination impairment or ostalgia. During the study, 1,000 men aged > or = 50 from the community of Cepin and village of Josipovac near Osijek were examined. The subjects with elevated concentration of total prostate specific antigen and/or digital rectal examination suspect of carcinoma underwent transperineal biopsy of the prostate. Clinical staging was performed in patients with prostate cancer detected on screening, and data on clinical staging for prostate cancer patients treated during the 1996-1997 period were retrieved from patient files of the Department of Urology, University Hospital "Osijek". On screening, 28 (80%) patients with localized prostate cancer and seven (20%) patients with metastases were detected. In the group of patients examined on an outpatient basis for the signs and symptoms of prostatism, there were 30 (83.4%) patients with metastases and only six (16.6%) patients with localized prostate cancer. Study results indicated that an early diagnosis of prostate cancer could be made by use of noninvasive and inexpensive methods that cause no major discomfort to the patient. Accordingly, these results appear to strongly support such screening in men, if not in all those aged over 50, then at least in the otherwise healthy, 50-70 age group.  相似文献   
925.
The aim of this study is to determine the differences in sexual life of women with cervical cancer after surgery and radiation therapy. A total of 210 patients treated for cervical cancer at the Department of Obstetrics and Gynecology, School of Medicine, University of Zagreb, Croatia between March 2001 and March 2003 were asked to fill in the questionnaire. Sexual life had worsened in 42.86% of the surgical patients, as had in 25.00% of irradiated patients (p < 0.01). The main reason of sex life impairment was fear of pain (55.55% and 42.86%, respectively (p > 0.05)). More than 80% of patients didn't notice any changes in their partner's behavior. Almost every third woman felt certain change in her "body image", similar in both groups (p > 0.05). Need for consultations regarding sex life after diagnosis were recognized by 71.43% of patients. In conclusion we can say that considerable amount of attention should be given to psychological and sexual aspects of recovery of patients, because those aspects can significantly influence patients rehabilitation and prognosis.  相似文献   
926.
The elicitation of contact sensitivity (CS) to local skin challenge with the hapten trinitrophenyl (TNP) chloride requires an early process that is necessary for local recruitment of CS-effector T cells. This is called CS initiation and is due to the B-1 subset of B cells activated at immunization to produce circulating IgM Ab. At challenge, the IgM binds hapten Ag in a complex that locally activates C to generate C5a that aids in T cell recruitment. In this study, we present evidence that CS initiation is indeed mediated by C-activating classic IgM anti-TNP pentamer. We further demonstrate the involvement of IgM subunits derived either from hybridomas or from lymphoid cells of actively immunized mice. Thus, reduced and alkylated anti-TNP IgM also initiates CS, likely due to generated H chain-L chain dimers, as does a mixture of separated H and L chains that still could weakly bind hapten, but could not activate C. Remarkably, anti-TNP kappa L chains alone mediated CS initiation that was C-independent, but was dependent on mast cells. Thus, B-1 cell-mediated CS initiation required for T cell recruitment is due to activation of C by specific IgM pentamer, and also subunits of IgM, while kappa L chains act via another C-independent but mast cell-dependent pathway.  相似文献   
927.
The susceptibility of a fourth generation Ouh strain (Paranapanema Valley, S?o Paulo, Brazil) of Schistosoma mansoni to oxamniquine (OXA) and praziquantel (PZQ) was studied. Ten groups of 13 female albino mice each were infected with 70 cercariae per animal. These mice were medicated orally on the 50th day after infection. Five groups were given OXA doses of 0, 100, 200, 300 and 400 mg/kg (single doses) and the rest were treated with PZQ doses of 0, 100, 200, and 250 mg/kg/5 days. Each group was sub-divided: 8 animals underwent perfusion after 15 days treatment, 5 mice followed up for oviposition and their feces were tested every 15 days for miracidia hatching. The efficacy of the OXA doses of 100 and 200 mg/kg was 66% and 91.4%, respectively and for the 100 mg/kg PZQ dose it was 90.1%. The follow-up groups with 100 and 200 mg/kg of OXA and PZQ, 100 and 150 mg/kg, showed that they re-established the oviposition after a period of 60 to 75 days of treatment. The ED50 was 69.6 mg/kg OXA and 39.4 mg/kg PZQ. The results show the tolerance of the Ouh strain to a dose of 100 mg with both drugs and they appoint the need for a dose review during the follow up of the oviposition and in monitoring phenomena in the field.  相似文献   
928.
The therapeutic value of DNA-damaging antineoplastic agents is dependent upon their ability to induce tumor cell apoptosis while sparing most normal tissues. Here, we show that a component of the apoptotic response to these agents in several different types of tumor cells is the deamidation of two asparagines in the unstructured loop of Bcl-xL, and we demonstrate that deamidation of these asparagines imports susceptibility to apoptosis by disrupting the ability of Bcl-xL to block the proapoptotic activity of BH3 domain-only proteins. Conversely, Bcl-xL deamidation is actively suppressed in fibroblasts, and suppression of deamidation is an essential component of their resistance to DNA damage-induced apoptosis. Our results suggest that the regulation of Bcl-xL deamidation has a critical role in the tumor-specific activity of DNA-damaging antineoplastic agents.  相似文献   
929.
We have identified and sequenced the genes encoding the aggregation-promoting factor (APF) protein from six different strains of Lactobacillus johnsonii and Lactobacillus gasseri. Both species harbor two apf genes, apf1 and apf2, which are in the same orientation and encode proteins of 257 to 326 amino acids. Multiple alignments of the deduced amino acid sequences of these apf genes demonstrate a very strong sequence conservation of all of the genes with the exception of their central regions. Northern blot analysis showed that both genes are transcribed, reaching their maximum expression during the exponential phase. Primer extension analysis revealed that apf1 and apf2 harbor a putative promoter sequence that is conserved in all of the genes. Western blot analysis of the LiCl cell extracts showed that APF proteins are located on the cell surface. Intact cells of L. johnsonii revealed the typical cell wall architecture of S-layer-carrying gram-positive eubacteria, which could be selectively removed with LiCl treatment. In addition, the amino acid composition, physical properties, and genetic organization were found to be quite similar to those of S-layer proteins. These results suggest that APF is a novel surface protein of the Lactobacillus acidophilus B-homology group which might belong to an S-layer-like family.  相似文献   
930.
An occurrence of the toxigenic fungi producing aflatoxins and ochratoxin A in food was investigated in the study (“MYCOMON”) in years 1999–2001. Twenty five commodities were purchased from retail in twelve collection places in the Czech Republic (300 food samples together). The presence of potentially toxigenic fungiAspergillus flavus was observed in 28% of the sampled food (black pepper, black tea, caraway seeds, fine flour, fruit tea, oat flakes) in the year 1999, in 17% of the sampled food (black pepper, black tea, caraway seeds, fine flour, fruit tea, oat flakes) in the year 2000 and in 18% of the sampled food (black pepper, black tea, caraway seeds, fine flour, fruit tea, oat flakes) in the year 2001.Aspergillus tamarii (aflatoxins producer) was found in black pepper samples (25%) in year 1999, in black pepper samples and black tea (25%) in year 2000 and in black pepper samples and black tea (21%) in year 2001.Aspergillus parasiticus andAspergillus nomius were not isolated.Aspergillus sectionNigri (potential producer of ochratoxin A) was detected in some food (black pepper, black tea, caraway seeds, fine flour, fruit tea, raisins, sweet red pepper).Penicillium verrucosum and Aspergillus ochraceus were not isolated from the tested food.  相似文献   
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