首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9755篇
  免费   865篇
  国内免费   444篇
耳鼻咽喉   152篇
儿科学   209篇
妇产科学   154篇
基础医学   1123篇
口腔科学   132篇
临床医学   1244篇
内科学   1420篇
皮肤病学   85篇
神经病学   402篇
特种医学   472篇
外国民族医学   1篇
外科学   883篇
综合类   1382篇
现状与发展   5篇
一般理论   3篇
预防医学   812篇
眼科学   243篇
药学   1013篇
  12篇
中国医学   540篇
肿瘤学   777篇
  2024年   45篇
  2023年   140篇
  2022年   396篇
  2021年   463篇
  2020年   392篇
  2019年   341篇
  2018年   339篇
  2017年   328篇
  2016年   342篇
  2015年   443篇
  2014年   570篇
  2013年   544篇
  2012年   743篇
  2011年   821篇
  2010年   492篇
  2009年   408篇
  2008年   461篇
  2007年   506篇
  2006年   475篇
  2005年   439篇
  2004年   315篇
  2003年   292篇
  2002年   257篇
  2001年   176篇
  2000年   175篇
  1999年   210篇
  1998年   115篇
  1997年   108篇
  1996年   76篇
  1995年   84篇
  1994年   66篇
  1993年   51篇
  1992年   47篇
  1991年   55篇
  1990年   48篇
  1989年   52篇
  1988年   30篇
  1987年   33篇
  1986年   31篇
  1985年   31篇
  1984年   14篇
  1983年   10篇
  1981年   12篇
  1980年   7篇
  1979年   6篇
  1978年   7篇
  1975年   6篇
  1974年   14篇
  1973年   6篇
  1971年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
急性脑梗死患者血浆神经肽Y的动态变化及临床意义   总被引:7,自引:0,他引:7  
目的 观察急性脑梗死(acute cerebral infarction,ACI)患者血浆神经肽Y(neuropeptide Y,NPY)含量的动态变化及临床意义。方法 选择ACI患者51例,采用放射免疫分析法检测血浆NPY浓度,并以50例健康人作为对照。结果 ACI组血浆NPY水平于发病7d时显著高于对照组(P<0.01),3周后降至正常;病情严重组显著高于轻、中型组(P<0.05);大病灶组显著高于小病灶组(P<0.05)。结论 NPY不仅参与了急性脑梗死的病理生理过程,而且与病情轻重有关。  相似文献   
72.
目的 探讨输尿管镜下尿道会师术治疗尿道骑跨伤的临床价值.方法 对17例尿道骑跨伤患者采用输尿管镜引导放置导尿管,随访观察手术的效果.结果 17例中,3例因尿道完全断裂,镜下会师失败后,2例改行开放会师术,1例行耻骨上膀胱穿刺造瘘术;其余14例采用输尿管镜下尿道会师术均1次成功.术后均获随访 0.5~1年,除2例排尿明显变细、需定期尿道扩张外,其余患者未出现尿道狭窄、尿失禁、性功能障碍等并发症.结论 输尿管镜下尿道会师术手术时间短、创伤小、恢复快、效果好,是治疗尿道骑跨伤的有效方法.  相似文献   
73.
目的:观察“长骨液”对下肢骨延长术后的治疗效果。方法:56例患者分为长骨液组和对照组进行配对对照观察。于术后第3天开始口服长骨液。观察骨延长区新骨生长情况、肢体伤后肿胀及并发症发生的情况。结果:①对照组平均骨延长愈合指数为41.797±3.5862(d/cm),治疗组平均骨延长愈合指数为36.291±2.8969(d/cm)(P<0.01)。②治疗组的46例病例平均骨延长愈合指数为37.121±2.2176(d/cm),明显低于国内报道指数。结论:“长骨液”有明显促进骨延长区新骨再生与成熟及减少并发症的作用。  相似文献   
74.
对沙土鼠(gerbil)进行单侧颈总动脉结扎,做成单侧脑缺血的动物模型,运用高效液相色谱电化学检测仪测定,研究额叶皮质区、尾状核区、海马区内神经递质多巴胺及5羟色胺在恢复过程中不同存活期内的含量变化,其中下降最显著的在海马组内,损伤侧DA下降到仅占对照侧的33%,P<0.01(第七天);在尾状核组内,5HT下降到仅占对照侧的38%,P<0.01(第七天),但额叶皮质组内二者变化不显著,为防治脑血管疾患提供了客观指标。  相似文献   
75.
BackgroundThis study aimed to examine the prognostic significance of sarcopenia combined with systemic inflammation in patients who underwent curative hepatectomy for hepatocellular carcinoma (HCC).MethodsBetween January 2010 and July 2019, we identified 159 patients with HCC who underwent curative hepatectomy at three institutional centers. We retrospectively analyzed clinicopathological outcomes, surgical outcomes, platelet lymphocyte ratio (PLR) as a systemic inflammatory marker, and computed tomography (CT)-assessed sarcopenia at the third lumbar vertebra level (L3).ResultsSarcopenia was noted in 74 (46.5%) of 159 patients and was significantly associated with male sex, low body mass index (BMI), and high PLR. In the multivariate analysis, sarcopenia [hazard ratio (HR): 2.127, P=0.026] and high PLR (HR: 1.971, P=0.038) were associated with a decrease in overall survival (OS) but not in recurrence-free survival (RFS). The combination of sarcopenia and PLR status stratified the 5-year OS into 82.0% (non-sarcopenia and a low PLR), 68.3% (sarcopenia or a high PLR), and 44.4% (sarcopenia and a high PLR) (P=0.001). In the multivariate analysis, “sarcopenia and a high PLR” and “sarcopenia or a high PLR” were revealed to be significant predictors of OS (HR: 4.300, P=0.001 and HR: 2.723, P=0.010, respectively).ConclusionsSarcopenia and high PLR were significantly associated with poor OS. The combination of these two factors may be useful for predicting survival of patients with HCC undergoing curative hepatectomy.  相似文献   
76.
BackgroundPoor prognosis is common in gastric cancer patients due to multidrug resistance (MDR)-induced recurrence and metastasis. In the present study, we investigated the expression of microRNA (miR)-200c in gastric cancer tissues and cell lines and its relationship with the expression of the drug resistant gene ABCB1, which encodes P-glycoprotein (P-gp).MethodsThe basic characteristics of 102 patients with gastric cancer were reviewed. Real time-polymerase chain reaction (PCR), immunohistochemistry, and Western blot were employed to detect the expression levels of miR-200c and P-gp in gastric carcinoma tissues and cell lines. The correlation of miR-200c messenger RNA (mRNA) level with clinicopathological characteristics and P-gp protein expression were analyzed. SGC7901/vincristine (VCR) cells were transfected with miR-200c mimics or a specific small interfering RNA (siRNA) targeting the ABCB1 gene. The methyl thiazolyl tetrazolium (MTT) assay and flow cytometry were used to determine the role of miR-200c and ABCB1 on the viability and apoptosis of gastric carcinoma cell lines.ResultsThe level of miR-200c in carcinoma tissues was significantly lower than that in adjacent tissues, and the expression level of P-gp in carcinoma tissues was obviously higher than that in adjacent tissues (P<0.01, P=0.029). The expression levels of miR-200c and P-gp were associated with the malignant characteristics of gastric cancer, and patients with high expression of miR-200c or negative expression of P-gp had a better prognosis (P=0.006, P=0.022). MiR-200c negatively regulated the ABCB1 gene in gastric cancer cell lines. MiR-200c overexpression and ABCB1 down-regulation increased the sensitivity of SGC7901/VCR cells to VCR and reversed MDR by promoting cell apoptosis.ConclusionsThe expression level of miR-200c decreases in gastric carcinoma tissues and drug-resistant gastric cancer SGC7901/VCR cells. Overexpression of miR-200c may enhance the sensitivity of SGC7901/VCR cells to VCR by regulating the expression of P-gp.  相似文献   
77.
A pharmacokinetic study in patients with gastrointestinal stromal tumors (GIST) suggested that imatinib plasma concentration may decrease following long-term exposure. We assessed changes in imatinib plasma trough levels (C(min)) during long-term treatment. Follow-up (FU) imatinib C(min) was measured in 65 patients who received the same dose of imatinib for at least 9 months after previous (initial) tests. After exclusion of 7 patients who had been treated with imatinib for over 2 years at the time of initial testing, 58 patients were included in this analysis. The median intervals from initiation of imatinib to initial testing and from initial to FU testing were 5.5 months (range, 0.5-24.0 months) and 13.0 months (range, 9.6-17.9 months), respectively. Mean inter- and intra-subject variability values were 47.7% and 20.9%, respectively, at initial measurements, and 45.2% and 19.4%, respectively, at FU. Mean FU imatinib C(min) (1,370 ± 661 ng/mL) was significantly higher than mean initial C(min) (1,171 ± 573 ng/mL; p = 0.003). Compared with initial C(min), FU C(min) was decreased in 22 patients and increased in 36, with median changes of 13% and 32%, respectively. Multivariate analysis showed a significant correlation between the ratio of FU to initial imatinib C(min) and that of albumin (r = -0.39, p = 0.003). During long-term treatment, imatinib C(min) did not decrease significantly but remained stable or increased in most patients. Changes in imatinib C(min) were associated with changes in albumin concentration. Monitoring of imatinib C(min) only for concerns about time-dependent increases in imatinib clearance is not necessary.  相似文献   
78.
79.
The K-I and nephropathogenic K-II genotypes of infectious bronchitis virus (IBV) have been isolated since 1995 and 1990, respectively, in Korea and commercial inactivated oil-emulsion vaccines containing KM91 (K-II type) and Massachusetts 41 strains have been used in the field. To date, genomic analyses of Korean IBV strains and animal models to test the pathogenicity of Korean IBVs to the reproductive organs have been rare. In the present study, comparative genomics of SNU8067 (K-I type) and KM91 IBVs was performed, and an animal model to test the pathogenicity of SNU8067 was established and applied to vaccine efficacy test. The genome sizes of SNU8067 (27,708 nt) and KM91 (27,626 nt) were slightly different and the nucleotide and amino acid identities of the S1 (79%, 77%), 3a (65%, 52%), and 3b (81%, 72%) genes were lower than those of other genes (94%–97%, 92%–98%). A recombination analysis revealed that SNU8067 was a recombinant virus with a KM91-like backbone except S1, 3a, and 3b genes which might be from an unknown virus. An SNU8067 infection inhibited formation of hierarchal ovarian follicles (80%) and oviduct maturation (50%) in the control group, whereas 70% of vaccinated chickens were protected from lesions.  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号