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   432838篇
  免费   35214篇
  国内免费   12597篇
耳鼻咽喉   3203篇
儿科学   7544篇
妇产科学   6173篇
基础医学   66503篇
口腔科学   7557篇
临床医学   32996篇
内科学   75309篇
皮肤病学   6011篇
神经病学   27728篇
特种医学   12081篇
外国民族医学   62篇
外科学   31869篇
综合类   58644篇
现状与发展   55篇
一般理论   16篇
预防医学   28204篇
眼科学   5387篇
药学   57110篇
  126篇
中国医学   22150篇
肿瘤学   31921篇
  2024年   876篇
  2023年   6444篇
  2022年   14557篇
  2021年   19525篇
  2020年   15502篇
  2019年   14312篇
  2018年   14365篇
  2017年   14928篇
  2016年   15190篇
  2015年   16005篇
  2014年   22260篇
  2013年   28127篇
  2012年   23479篇
  2011年   27312篇
  2010年   20600篇
  2009年   20815篇
  2008年   21881篇
  2007年   21843篇
  2006年   19863篇
  2005年   17836篇
  2004年   15191篇
  2003年   13481篇
  2002年   10774篇
  2001年   9512篇
  2000年   7997篇
  1999年   6977篇
  1998年   6066篇
  1997年   5869篇
  1996年   5332篇
  1995年   4795篇
  1994年   4455篇
  1993年   3739篇
  1992年   3190篇
  1991年   2922篇
  1990年   2564篇
  1989年   2146篇
  1988年   2015篇
  1987年   1704篇
  1986年   1611篇
  1985年   2390篇
  1984年   2141篇
  1983年   1488篇
  1982年   1644篇
  1981年   1319篇
  1980年   1219篇
  1979年   965篇
  1978年   670篇
  1977年   550篇
  1976年   537篇
  1975年   365篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area.  相似文献   
42.
Transient stress hyperglycemia in the setting of acute myocardial infarction is a frequent phenomenon. Its transient nature should not dissuade the clinician from management of elevated blood glucose in a patient after an ST-elevation myocardial infarction. This case presents an adult patient after an ST-elevation myocardial infarction with transient stress hyperglycemia and the evidence used to identify optimal pharmacologic management and secondary prevention.  相似文献   
43.
44.
《Pancreatology》2022,22(8):1175-1180
BackgroundHepatic steatosis has been described as a common finding in adults following total pancreatectomy with islet autotransplantation (TPIAT) but it is unknown if this occurs in children and adolescents.ObjectivesTo define the frequency of post-TPIAT hepatic steatosis in a sample of children and adolescents and to identify clinical predictors of incident steatosis post-TPIAT.MethodsIn this prospective study, consecutive participants at least 1-month post-TPIAT underwent a liver MRI with proton density fat fraction (PDFF) and blood draw at our pediatric academic medical center between April 2021 and January 2022. Comparison clinical pre-TPIAT liver MRI or ultrasound and insulin use and graft function data were extracted from the medical record. T-tests were used for the comparison of means across continuous variables between participants with and without post-TPIAT steatosis.ResultsA total of 20 participants (mean: 13 ± 4 years; 12 female) were evaluated. Mean liver PDFF at research MRI was 7.4 ± 6.2% (range: 2–25%). Seven participants (35%) had categorical hepatic steatosis (PDFF>5%) post-TPIAT, five of whom had pre-TPIAT steatosis, reflecting a 13% (2/15; 95% CI: 2–40%) incidence of post-TPIAT steatosis. Participant characteristics were not significantly different between subgroups with and without post-TPIAT steatosis. Mean PDFF at research MRI was not different between graft function subgroups (7.5% optimal/good vs. 7.3% marginal/failure; p = .96).ConclusionOur study shows a moderate prevalence but low incidence of hepatic steatosis in a small sample of children and adolescents post-TPIAT. This study raises questions about a causal relationship between TPIAT and hepatic steatosis.  相似文献   
45.
《Vaccine》2022,40(30):4038-4045
PurposeAs protection from COVID-19 following two doses of the BNT162b2 vaccine showed a time dependent waning, a third (booster) dose was administrated. This study aims to compare the antibody response following the third dose versus the second and to evaluate post-booster seroconversion.MethodsA prospective observational study conducted in Maccabi Healthcare Services. Serial SARS-CoV-2 Spike IgG tests, 1,2,3 and 6 months following the second vaccine dose and one month following the third were obtained. Neutralizing antibody levels were measured in a subset of participants. Per individual SARS-CoV-2 Spike IgG titer ratios were calculated one month after the booster administration compared to titers one month following the second dose and prior to booster.ResultsAmong 110 participants, 56 (51%) were women. Mean age was 61.7 ± 1.9 years and 66 (60%) were immunocompromised. One month after third dose, IgG titers were induced 7.83 (95 %CI 5.25–11.67) folds and 2.40 (95 %CI 1.90–3.03) folds compared to one month after the second, in the immunocompromised and immunocompetent groups, respectively. Of the 17 immunocompromised participants who were seronegative after the second dose, 4 (24%) became seropositive following the third. Comparing the titers prior to the third dose, an increase of 50.7 (95 %CI 32.5–79.1) fold in the immunocompromised group and 25.7 (95 %CI 19.1–34.7) fold in and immunocompetent group, was observed.ConclusionA third BNT162b2 vaccine elicited robust humoral response, superior to the response observed following the second, among immunocompetent and immunocompromised individuals.  相似文献   
46.
BackgroundOverweight and obesity have been observed in children with type 1 diabetes (T1D). This further increases their future risk of Cardiovascular Disease (CVD) as well as the development of other risk factors, such as dyslipidemia.AimsTo compare lipid profiles in children and adolescents with Type 1 diabetes and lean mass (T1L), Type 1 diabetes and overweight or obese (T1OW/OB), and type 2 diabetes (T2D).MethodsThis was a cross-sectional study of 669 patients with T1D or T2D aged 2–19 years using retrospective data collected from 2003 to 2014. Included patients were categorized into lean (BMI < 85th ile and overweight or Obese (BMI ≥ 85th ile). Patients were subcategorized into three age groups: < 10 years, 10–14 years, and 15–19 years.Results7.6% of patients had T2D. Of the patients with T1D, 58.9% were lean, 26.4% were overweight, and 14.7% were obese. Total Cholesterol (TC), Low-density lipoprotein cholesterol (LDL-C) and Non-HDL-C levels were similar across groups. In the 15–19 years group, Triglycerides (TG) levels were significantly higher in T1OW/OB and similar to T2D. High-density lipoprotein Cholesterol (HDL-C) was significantly lower in T2D. Weight status significantly correlated with TG and HDL-C levels in T1D and T2D groups.ConclusionsT1OW/OB constitutes a significant proportion of the T1D population. Patients with obesity and T1D, especially if in their late adolescence, have an adverse lipid profile pattern that is comparable to adolescents with T2D. Based on these findings, risk for future CVD in T1OW/OB and T2D may be equivalent.  相似文献   
47.
48.
49.
目的:探讨健脾益肾方对非小细胞肺癌(NSCLC)细胞体外增殖凋亡的作用。方法:人NSCLC细胞系A549分为四组:空白对照组(仅加入细胞培养液)、阴性对照组(加入细胞,不进行中药处理)、实验组(加细胞加中药处理)。荧光定量PCR和Western blot分别检测Survivin、Bcl-2和Caspase-3的mRNA和蛋白表达。MTT检测细胞增殖;流式细胞术检测细胞凋亡。结果:与空白对照组相比,阴性对照组细胞在24、48、72 h的吸光度值明显升高,细胞凋亡率下降,Survivin和Bcl-2 mRNA和蛋白相对表达量上调,Caspase-3 mRNA和蛋白相对表达量下调,组间比较差异有统计学意义(P<0.05);而健脾益肾方处理的实验组24、48、72 h的吸光度值均显著降低,细胞凋亡率显著上升,Survivin和Bcl-2 mRNA和蛋白相对表达量下调,Caspase-3 mRNA和蛋白相对表达量上调,与空白对照组相比差异有统计学意义(P<0.05)。结论:健脾益肾方可通过下调Survivin和Bcl-2、上调Caspase-3表达诱导NSCLC细胞凋亡,并抑制肿瘤细胞的增殖,进而抑制NSCLC的发展。  相似文献   
50.
MicroRNAs (miRNAs) play important roles in prostate cancer development. However, it remains unclear how individual miRNAs contribute to the initiation and progression of prostate cancer. Here we show that a basal layer‐enriched miRNA is required for prostate tumorigenesis. We identify miR‐205 as the most highly expressed miRNA and enriched in the basal cells of the prostate. Although miR‐205 is not required for normal prostate development and homeostasis, genetic deletion of miR‐205 in a Pten null tumor model significantly compromises tumor progression and does not promote metastasis. In Pten null basal cells, loss of miR‐205 attenuates pAkt levels and promotes cellular senescence. Furthermore, although overexpression of miR‐205 in prostate cancer cells with luminal phenotypes inhibits cell growth in both human and mouse, miR‐205 has a minimal effect on the growth of a normal human prostate cell line. Taken together, we have provided genetic evidence for a requirement of miR‐205 in the progression of Pten null‐induced prostate cancer.  相似文献   
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