全文获取类型
收费全文 | 1551篇 |
免费 | 114篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 82篇 |
妇产科学 | 11篇 |
基础医学 | 158篇 |
口腔科学 | 39篇 |
临床医学 | 132篇 |
内科学 | 278篇 |
皮肤病学 | 33篇 |
神经病学 | 93篇 |
特种医学 | 138篇 |
外科学 | 158篇 |
综合类 | 171篇 |
预防医学 | 109篇 |
眼科学 | 16篇 |
药学 | 124篇 |
中国医学 | 39篇 |
肿瘤学 | 79篇 |
出版年
2023年 | 9篇 |
2022年 | 22篇 |
2021年 | 33篇 |
2020年 | 32篇 |
2019年 | 26篇 |
2018年 | 33篇 |
2017年 | 23篇 |
2016年 | 29篇 |
2015年 | 34篇 |
2014年 | 56篇 |
2013年 | 63篇 |
2012年 | 68篇 |
2011年 | 86篇 |
2010年 | 92篇 |
2009年 | 65篇 |
2008年 | 40篇 |
2007年 | 55篇 |
2006年 | 58篇 |
2005年 | 47篇 |
2004年 | 35篇 |
2003年 | 49篇 |
2002年 | 25篇 |
2001年 | 34篇 |
2000年 | 21篇 |
1999年 | 31篇 |
1998年 | 51篇 |
1997年 | 65篇 |
1996年 | 58篇 |
1995年 | 45篇 |
1994年 | 36篇 |
1993年 | 33篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 20篇 |
1989年 | 30篇 |
1988年 | 24篇 |
1987年 | 22篇 |
1986年 | 22篇 |
1985年 | 16篇 |
1984年 | 19篇 |
1983年 | 7篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 12篇 |
1979年 | 9篇 |
1977年 | 13篇 |
1976年 | 10篇 |
1975年 | 5篇 |
1974年 | 6篇 |
1958年 | 5篇 |
排序方式: 共有1683条查询结果,搜索用时 15 毫秒
51.
摘要:目的 探讨白花蛇舌草-半枝莲药对组分对结肠腺癌Lovo细胞增殖、侵袭、迁移和凋亡的影响及作用机制。方法 将白花蛇舌草、半枝莲按质量1∶1进行3次煎煮,获得水提物,后取适量浸膏用石油醚回流脱脂,再以乙酸乙酯进行多次萃取,获得白花蛇舌草-半枝莲药对组分,并计算得率。实验分为对照组(正常培养Lovo细胞)、白花蛇舌草-半枝莲药对组分低剂量组(10 mg/L)、中剂量组(30 mg/L)及高剂量组(50 mg/L)。通过噻唑蓝比色法(MTT)检测各组细胞培养24、48、72 h后的增殖抑制率。各组细胞培养48 h后,流式细胞仪检测细胞周期分布;Transwell实验检测细胞侵袭能力;划痕实验检测细胞迁移能力;TUNEL法检测细胞凋亡情况;Western blot法检测Grb2相关结合蛋白1(Gab1)、血管内皮生长因子受体2(VEGFR-2)、磷脂酰肌醇3-激酶(PI3K)、苏氨酸激酶(Akt)、基质金属蛋白酶-9(MMP-9)、B淋巴细胞瘤-2基因(Bcl-2)、Bcl-2相关X蛋白(Bax)蛋白表达情况。结果 化学萃取后的白花蛇舌草-半枝莲药对中主要含有对羟基苯乙酮、野黄芩苷、木犀草素和芹菜素4种化合物,组分得率为0.61%。与对照组相比,低、中、高剂量组细胞增殖抑制率升高,G1期肿瘤细胞比例增加,细胞凋亡指数增高,侵袭细胞数和划痕闭合率明显减小(均P<0.05),细胞中Gab1、VEGFR-2、PI3K、Akt、MMP-9、Bcl-2蛋白表达降低,Bax表达升高(均P<0.05),且存在剂量依赖性。结论 白花蛇舌草-半枝莲药对组分可抑制结肠腺癌Lovo细胞的增殖,降低其迁移和侵袭能力,诱导细胞凋亡,其机制可能与抑制Gab1/VEGFR-2/PI3K/Akt信号通路活化有关。 相似文献
52.
Xu Yaqian Surface Matthew Chan Amanda K. Halpern Joshua Vanegas-Arroyave Nora Ford Blair Feeney Megan P. Kwei Kimberly T. Katus Linn E. Kuo Sheng-Han Shah Hiral Waters Cheryl Winfield Linda M. Beck James C. Przedborski Serge Fahn Stanley Alcalay Roy N. 《Journal of neurology》2022,269(3):1107-1113
Journal of Neurology - With the explosion of COVID-19 globally, it was unclear if people with Parkinson’s disease (PD) were at increased risk for severe manifestations or negative outcomes.... 相似文献
53.
Pneumothoraces are a possible sequela of chest trauma with potential morbidity and mortality if not recognized and treated promptly. A portable supine chest radiograph is frequently the first radiologic study performed in the setting of trauma. While large pneumothoraces can be readily recognized on these radiographs, smaller pneumothoraces are missed in up to 15 % of trauma patients. There are many radiographic signs of occult pneumothoraces, and we are presenting a new radiographic sign of occult pneumothorax. The floating cardiac fat pad sign occurs when pleural air collects anteriorly and superiorly in the most non-dependent portion of the chest lifting the pericardial fat pad off the diaphragm. Lung markings are still seen surrounding the pericardial fat pad due to the inflated lower lobe of the lung resting dependently. Rapid and accurate identification of pneumothoraces is critical but often difficult on chest radiographs. Although there are many existing radiographic signs for identification of pneumothorax, prospective identification of small pneumothoraces is still relatively poor. Here, we describe an additional sign which aides in the detection of pneumothoraces, the floating cardiac fat pad. When present, this should prompt further evaluation with chest CT or upright chest radiograph. 相似文献
54.
Larimer ME Lee CM Kilmer JR Fabiano PM Stark CB Geisner IM Mallett KA Lostutter TW Cronce JM Feeney M Neighbors C 《Journal of consulting and clinical psychology》2007,75(2):285-293
The current study was designed to evaluate the efficacy of a mailed feedback and tips intervention as a universal prevention strategy for college drinking. Participants (N = 1,488) were randomly assigned to feedback or assessment-only control conditions. Results indicated that the mailed feedback intervention had a preventive effect on drinking rates overall, with participants in the feedback condition consuming less alcohol at follow-up in comparison with controls. In addition, abstainers in the feedback condition were twice as likely to remain abstinent from alcohol at follow-up in comparison with control participants (odds ratio = 2.02), and feedback participants were significantly more likely to refrain from heavy episodic drinking (odds ratio = 1.43). Neither gender nor severity of baseline drinking moderated the efficacy of the intervention in these analyses, but more conservative analyses utilizing last-observation carryforward suggested women and abstainers benefited more from this prevention approach. Protective behaviors mediated intervention efficacy, with participants who received the intervention being more likely to use strategies such as setting limits and alternating alcohol with nonalcoholic beverages. Implications of these findings for universal prevention of college drinking are discussed. 相似文献
55.
目的:观察五禽戏联合推拿治疗原发性痛经(PD)的临床疗效及对患者血清肿瘤坏死因子-α(TNF-α)、CD4+、催产素(OT)及β-内啡肽(β-EP)水平的影响。方法:选取80例PD女大学生,按随机数字表法分为对照组、五禽戏组、推拿组及五禽戏+推拿组,对照组给予田七痛经胶囊治疗,其余3组分别给予五禽戏、推拿及五禽戏+推拿治疗,治疗时间均为3个月经周期。采用中医证候积分评价临床疗效,通过血清TNF-α、CD4+、OT、β-EP表达的变化探讨五禽戏联合推拿治疗PD的作用机制。结果:与治疗前比较,4组中医证候积分治疗1个疗程、2个疗程、3个疗程后均降低(P<0.05),且随着疗程增加逐渐降低。停止治疗3个月后,4组中医证候积分均较治疗3个疗程时上升(P<0.05);五禽戏+推拿组中医证候积分低于五禽戏组和推拿组,差异均有统计学意义(P<0.05)。治疗后,4组血清TNF-α、OT水平均较治疗前降低(P<0.05),血清CD4+、β-EP水平均较治疗前升高(P<0.05)。4组治疗后CD4+、OT水平比较,差异均有统计学意义(P<0.05),而TNF-α、β-EP水平比较,差异均无统计学意义(P>0.05)。治疗后,五禽戏+推拿组OT水平均低于对照组、五禽戏组及推拿组(P<0.05),CD4+水平高于对照组(P<0.05)。经秩和检验,4组临床疗效比较,差异无统计学意义(P>0.05)。结论:五禽戏联合推拿治疗PD有较好的近期及远期疗效,其作用机制可能与调节患者的血清TNF-α、CD4+、OT、β-EP水平有关。 相似文献
56.
57.
GA Antoniou D Murray SA Antoniou G Kuhan F Serracino-Inglott 《Annals of the Royal College of Surgeons of England》2014,96(3):184-189
Introduction
The retrojugular approach for carotid endarterectomy (CEA) has been reported to have the advantages of shorter operative time and ease of dissection, especially in high carotid lesions. Controversial opinion exists with regard to its safety and benefits over the conventional antejugular approach.Methods
A systematic review of electronic information sources was conducted to identify studies comparing outcomes of CEA performed with the retrojugular and antejugular approach. Synthesis of summary statistics was undertaken and fixed or random effects models were applied to combine outcome data.Findings
A total of 6 studies reporting on a total of 740 CEAs (retrojugular approach: 333 patients; antejugular approach: 407 patients) entered our meta-analysis models. The retrojugular approach was found to be associated with a higher incidence of laryngeal nerve damage (odds ratio [OR]: 3.21, 95% confidence interval [CI]: 1.46–7.07). No significant differences in the incidence of hypoglossal or accessory nerve damage were identified between the retrojugular and antejugular approach groups (OR: 1.09 and 11.51, 95% CI: 0.31–3.80 and 0.59–225.43). Cranial nerve damage persisting during the follow-up period was similar between the groups (OR: 2.96, 95% CI: 0.79–11.13). Perioperative stroke and mortality rates did not differ in patients treated with the retrojugular or antejugular approach (OR: 1.26 and 1.28, 95% CI: 0.31–5.21 and 0.25–6.50).Conclusions
Currently, there is no conclusive evidence to favour one approach over the other. Proof from a well designed randomised trial would help determine the role and benefits of the retrojugular approach in CEA. 相似文献58.
59.
The effects of granulocyte-macrophage colony-stimulating factor (GM- CSF) are not confined to cells of the myeloid lineage. GM-CSF has been shown to have effects on mature T cells and both mature and immature T- cell lines. We therefore examined the GM-CSF responsiveness of murine thymocytes to investigate whether GM-CSF also affected normal immature T lymphocytes. The studies presented here indicate that GM-CSF augments accessory cell (AC)-dependent T-cell receptor (TCR)-mediated proliferation of unseparated thymocyte populations. To identify the GM- CSF responsive cell type, thymic AC and T cells were examined for GM- CSF responsiveness. We found that GM-CSF augmentation of TCR-induced thymocyte proliferation appears to be mediated via augmentation of AC function, and not via direct effects on mature single-positive (SP) thymocytes. Enriched double-negative (DN) thymocytes were also tested for GM-CSF responsiveness. GM-CSF induced the proliferation of adult and fetal DN thymocytes in an AC-independent and TCR-independent single- cell assay. Thus, in contrast to the SP thymocytes, a DN thymocyte population was directly responsive to GM-CSF. GM-CSF therefore may play a direct role in the expansion of DN thymocytes and an indirect role in the expansion of SP thymocytes. 相似文献
60.
Verschraegen CF; Talpaz M; Hirsch-Ginsberg CF; Pherwani R; Rios MB; Stass SA; Kantarjian HM 《Blood》1995,85(10):2705-2710
The purpose of this report was to evaluate scintigraphy analysis of Southern blot hybridization as a method to quantify the breakpoint cluster region (BCR) rearrangement of Philadelphia chromosome (Ph)+ chronic myelogenous leukemia (CML). Cytogenetic and molecular studies performed simultaneously on 474 bone marrow and/or blood samples from 300 patients treated with alpha-interferon-based therapy were compared. Molecular results were expressed as the percentage of rearranged BCR bands versus the total scintigraphic signal. The percentage of Ph+ metaphases was calculated on 25 metaphases. The results of molecular studies obtained on both peripheral blood and bone marrow samples were identical. The rank correlation between the BCR quantification and the percentage of Ph positivity in 465 samples was excellent (r = .78). However, of 99 samples with a normal karyotype, 24% had a BCR rearrangement. Of 86 samples with no BCR rearrangement, 13% showed a Ph chromosome. Of 49 samples with partial cytogenetic remission (Ph+ metaphases, 1% to 34%), 23% had no BCR rearrangement. In samples with a minor or no cytogenetic response (Ph+ metaphases, > 34%), BCR analysis overestimated the degree of response in 73 of 326 samples (22%). Nevertheless, survival analysis by BCR quantification level showed statistically better outcome for patients in complete or partial molecular response (P < .01). Molecular quantification of BCR was useful in monitoring the course of Ph+ CML. This method, which can be used on peripheral blood, detected residual disease not shown by cytogenetic analysis and was prognostically relevant as a measure of disease suppression. 相似文献