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21.
小鼠皮肤超氧化物歧化酶活性与枸杞多糖的干预 总被引:1,自引:0,他引:1
目的:观察枸杞多糖对皮肤胶原代谢和自由基产生的影响,探讨其抗皮肤衰老的作用。方法:实验于2005-06/2006-05在广东医学院整形外科研究所完成。①实验材料:清洁级昆明小鼠60只,月龄2个月,体质量16~24g,雌雄各半。②实验分组:将小鼠随机分为正常对照组、衰老模型组和抗衰老模型组,每组20只。③实验干预:模型组每日用D-半乳糖溶液皮下注射制造衰老模型,用量和时间为80mg/(kg·d)7d,120mg/(kg·d)14d,140mg/(kg·d)14d,180mg/(kg·d)7d。正常对照组每日注射同体积的生理盐水。抗衰老模型组在注射D-半乳糖期间以枸杞多糖灌胃,剂量为20mg/(kg·d),正常对照组和衰老组则以同体积的生理盐水代之灌胃。④实验评估:42d后切取小鼠颈背部皮肤,测定超氧化物歧化酶活力、羟脯氨酸和丙二醛含量。结果:56只小鼠进入结果分析(4只死亡)。①小鼠皮肤超氧化物歧化酶活力:与正常对照组相比,衰老组和抗衰老组小鼠皮肤超氧化物歧化酶活力降低,差异有显著性意义(P<0.01);抗衰老组与衰老模型组比较,超氧化物歧化酶活力增加,差异有显著性意义(P<0.01)。②与正常对照组相比,衰老组和抗衰老组小鼠皮肤羟脯氨酸和丙二醛含量增加,差异有显著性意义(P<0.01);抗衰老组与衰老组比较,羟脯氨酸和丙二醛含量均降低,差异有显著性意义(P<0.01)。结论:枸杞多糖改善皮肤老化的作用与提高小鼠皮肤超氧化物歧化酶活力,降低羟脯氨酸、丙二醛含量,影响胶原代谢有关。 相似文献
22.
Aven‐mediated checkpoint kinase control regulates proliferation and resistance to chemotherapy in conventional osteosarcoma 下载免费PDF全文
Zuzanna Baranski Tijmen H Booij Anne‐Marie Cleton‐Jansen Leo S Price Bob van de Water Judith VMG Bovée Pancras CW Hogendoorn Erik HJ Danen 《The Journal of pathology》2015,236(3):348-359
Conventional high‐grade osteosarcoma is the most common primary bone sarcoma, with relatively high incidence in young people. In this study we found that expression of Aven correlates inversely with metastasis‐free survival in osteosarcoma patients and is increased in metastases compared to primary tumours. Aven is an adaptor protein that has been implicated in anti‐apoptotic signalling and serves as an oncoprotein in acute lymphoblastic leukaemia. In osteosarcoma cells, silencing Aven triggered G2 cell‐cycle arrest; Chk1 protein levels were attenuated and ATR–Chk1 DNA damage response signalling in response to chemotherapy was abolished in Aven‐depleted osteosarcoma cells, while ATM, Chk2 and p53 activation remained intact. Osteosarcoma is notoriously difficult to treat with standard chemotherapy, and we examined whether pharmacological inhibition of the Aven‐controlled ATR–Chk1 response could sensitize osteosarcoma cells to genotoxic compounds. Indeed, pharmacological inhibitors targeting Chk1/Chk2 or those selective for Chk1 synergized with standard chemotherapy in 2D cultures. Likewise, in 3D extracellular matrix‐embedded cultures, Chk1 inhibition led to effective sensitization to chemotherapy. Together, these findings implicate Aven in ATR–Chk1 signalling and point towards Chk1 inhibition as a strategy to sensitize human osteosarcomas to chemotherapy. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 相似文献
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24.
Apoptotic and proliferative indexes in esophageal cancer: predictors of response to neoadjuvant therapy [corrected]. 总被引:6,自引:0,他引:6
Duncan M Beardsmore Caroline S Verbeke Claire L Davies Pierre J Guillou Geoffrey W B Clark 《Journal of gastrointestinal surgery》2003,7(1):77-86; discussion 86-7
Altered expression of the genes that control apoptosis and proliferation may influence the response of cancer cells to cytotoxic agents. The primary aim of this study was to determine the role of the novel antiapoptotic and cell cycle gene, survivin, in apoptotsis and proliferation in esophageal cancer and to evaluate whether the survivin, p53, and bcl-2 status were able to predict a patient's response to neoadjuvant therapy. A total of 104 patients with esophageal tumors were studied. Tumor tissue was immunostained for survivin, p53, and bcl-2 proteins. Proliferative and apoptotic activity was measured using ki-67 immunohistochemical analysis and the TUNEL method, respectively. Forty-eight patients whose pretreatment biopsies were analyzed received neoadjuvant chemoradiation therapy or chemotherapy followed by surgery. Outcome was graded as a complete response, a partial response, or no response according to the results of histologic examination and CT imaging. Expression of survivin was found to correlate significantly with the proliferative index but not the apoptotic index. Patients who received neoadjuvant treatment were more likely to achieve a complete response if their tumors had high proliferative activity, and p53 positive tumors were more likely to contain residual tumor after treatment. In conclusion, survivin expression appears to foster proliferative activity in esophageal cancer, and tumors with a high proliferative index or a functioning p53 gene are more responsive to neoadjuvant chemoradiation therapy. 相似文献
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26.
Martijn W Heymans Dirk L Knol Willem van Mechelen Henrica CW de Vet 《BMC medical research methodology》2007,7(1):33
Background
Missing data is a challenging problem in many prognostic studies. Multiple imputation (MI) accounts for imputation uncertainty that allows for adequate statistical testing. We developed and tested a methodology combining MI with bootstrapping techniques for studying prognostic variable selection. 相似文献27.
The relationship between night cough and other indices of asthma severity was studied in 21 children with clinically stable asthma and persistent night cough. Overnight cough was quantified and related to symptom scores, oxygen saturation (SaO2) during sleep, evening and morning peak flow recordings and daytime tests of lung function. In the index group the median number of coughing episodes was 23 (range 1–158). Only 4 children had counts of <10 overnight, similar to the comparison group of 12 children all of whom had counts of <10. There was a trend towards the association of overnight cough with reduced evening peak flow (r=–0.407,P=0.07) and reduced SaO2 (r=–0.36,P=0.10). Abnormalities in daytime tests of lung function were observed in 13 children. There was no relationship between night cough and daytime indices of lung function abnormality although children with more severe daytime abnormalities also had significant night cough. Conversely, five children with chronic night cough had normal daytime function.Conclusion Night-time cough in children with asthma is not simply a reflection of daytime lung function status, whereas, overnight SaO2 correlates well. Other factors need to be explored to explain the variability of night-time cough in these children. 相似文献
28.
Kroese ED; Dortant PM; van Steeg H; van Oostrom CT; van der Houven van Oordt CW; van Kranen HJ; de Vries A; Wester PW; van Kreijl CF 《Carcinogenesis》1997,18(5):975-980
E mu-pim-1 transgenic mice are predisposed to develop lymphomas. Due to
their low spontaneous tumour incidence and their increased sensitivity
towards the lymphomagen ethylnitrosourea these mice may present an
interesting model for short-term carcinogenicity testing. Here, we report
on the further exploration of this transgenic mouse model with two
additional carcinogens known to have, among others, the
lymphohaematopoietic system as target, i.e. benzo[a]pyrene (B[a]P) and
12-O-tetradecanoylphorbol-13-acetate (TPA). B[a]P, given three times a week
(by gavage) for 13 weeks at 4.3, 13 or 39 mg/kg body weight, resulted in a
dose-related increase in lymphomas up to a 90% incidence in E(mu)-pim-1
mice during the observation period of 40 weeks. B[a]P also induced tumours
of the forestomach within this observation period, though at a lower
incidence and apparently equally effective in wildtype and transgenic mice.
TPA, on the other hand, was unable to induce lymphomas (or tumours in any
other organ) in either transgenic or wildtype animals within the
observation period of 44 weeks, when applied dermally at the maximum
tolerated dose of 3 microg/mouse, twice a week for 35 weeks. Molecular
analysis showed that B[a]P-induced lymphomas in transgenic mice were of
T-cell origin, 80% of which had elevated levels of c-myc expression. None
of the lymphomas had increased N-myc expression and mutation analysis of
the ras-gene family revealed a K-ras mutation in only one out of eight
tumours investigated. Also, none of the lymphomas showed aberrant
expression of p53 as determined by immunohistochemistry. It is concluded
that the E mu-pim-1 mouse model will not be very suitable for short-term
carcinogenicity testing in general: only genotoxic chemicals that have the
lymphohaematopoietic system as target for carcinogenesis in wild- type
mice, appear to be efficiently identified.
相似文献
29.
The effect of ketamine on the functional residual capacity (FRC) was measured in nine ASA class I children prior to elective surgery. FRC was determined by the closed-circuit helium dilution method on the day prior to surgery in the awake state and also following induction of anesthesia on the day of the operation. Anesthesia consisted of ketamine by continuous intravenous infusion following preanesthetic sedation with atropine and triclofos or flunitrazepam. There were no significant differences in FRC between the measurements in the awake state and anesthetized (392 +/- 43 SEM ml, and 411 +/- 53 SEM ml, respectively), and the authors conclude that ketamine does not affect resting lung volume in young children. 相似文献
30.