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   24572篇
  免费   1451篇
  国内免费   134篇
耳鼻咽喉   161篇
儿科学   463篇
妇产科学   393篇
基础医学   4082篇
口腔科学   647篇
临床医学   1910篇
内科学   4614篇
皮肤病学   916篇
神经病学   2731篇
特种医学   1673篇
外科学   3241篇
综合类   122篇
一般理论   8篇
预防医学   957篇
眼科学   402篇
药学   2226篇
中国医学   31篇
肿瘤学   1580篇
  2023年   84篇
  2021年   226篇
  2020年   259篇
  2019年   320篇
  2018年   359篇
  2017年   339篇
  2016年   430篇
  2015年   564篇
  2014年   722篇
  2013年   922篇
  2012年   1358篇
  2011年   1525篇
  2010年   979篇
  2009年   971篇
  2008年   1540篇
  2007年   1647篇
  2006年   1611篇
  2005年   1603篇
  2004年   1570篇
  2003年   1631篇
  2002年   1585篇
  2001年   310篇
  2000年   233篇
  1999年   332篇
  1998年   349篇
  1997年   300篇
  1996年   241篇
  1995年   261篇
  1994年   236篇
  1993年   229篇
  1992年   177篇
  1991年   159篇
  1990年   141篇
  1989年   138篇
  1988年   144篇
  1987年   143篇
  1986年   103篇
  1985年   117篇
  1984年   125篇
  1983年   120篇
  1982年   131篇
  1981年   130篇
  1980年   138篇
  1979年   76篇
  1978年   96篇
  1977年   105篇
  1976年   100篇
  1975年   83篇
  1974年   105篇
  1973年   77篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
The prospective, multicenter, noninterventional TACTIC study assessed effectiveness and safety of trifluridine/tipiracil (FTD/TPI) in patients with metastatic colorectal cancer (mCRC) in a real-world setting in Germany, thus evaluating the external validity of the findings from the pivotal RECOURSE trial. Primary endpoint was overall survival (OS). Secondary objectives included progression-free survival (PFS), safety, and quality of life (QoL). Subgroups comprised patients with good (<3 metastatic sites at inclusion, ≥18 months from diagnosis of first metastasis to inclusion) or poor (remaining patients) prognostic characteristics (GPC/PPC). GPC without liver metastases was considered best prognostic characteristics (BPC). In total, 307 eligible patients (pretreated or not suitable for other available therapies) were treated with FTD/TPI. Overall, median [95%-CI] OS was 7.4 months [6.4-8.6], median PFS was 2.9 months [2.8-3.3]. In BPC (n = 65) and GPC (n = 176) compared to PPC (n = 124) subgroup, median OS (13.3 [9.1-17.6] vs 8.9 [7.6-9.8] vs 5.1 [4.4-7.0] months) and median PFS (4.0 [3.3-5.3] vs 3.4 [3.0-3.7] vs 2.6 [2.4-2.8] months) were longer. Patient-reported QoL, assessed by validated questionnaires (EQ-5D-5L, PRO-CTCAE), was stable throughout FTD/TPI treatment. Predominant FTD/TPI-related adverse events of grades 3 or 4 were neutropenia (13.0%), leukopenia (7.5%), and anemia (5.2%). Altogether, palliative FTD/TPI therapy in patients with pretreated mCRC was associated with prolonged survival, delayed progression, maintained health-related QoL, and manageable toxicity. Low metastatic burden and indolent disease were favorable prognostic factors for survival. TACTIC confirms the effectiveness and safety of FTD/TPI, highlighting its value in routine clinical practice.  相似文献   
2.
Frameworks for deriving occupational exposure limits (OELs) and OEL-analogue values (such as derived-no-effect levels [DNELs]) in various regulatory areas in the EU and at national level in Germany were analysed. Reasons for differences between frameworks and possible means of improving transparency and harmonisation were identified. Differences between assessment factors used for deriving exposure limits proved to be one important reason for diverging numerical values. Distributions for exposure time, interspecies and intraspecies extrapolation were combined by probabilistic methods and compared with default values of assessment factors used in the various OEL frameworks in order to investigate protection levels. In a subchronic inhalation study showing local effects in the respiratory tract, the probability that assessment factors were sufficiently high to protect 99% and 95% of the target population (workers) from adverse effects varied considerably from 9% to 71% and 17% to 87%, respectively, between the frameworks. All steps of the derivation process, including the uncertainty associated with the point of departure (POD), were further analysed with two examples of full probabilistic assessments. It is proposed that benchmark modelling should be the method of choice for deriving PODs and that all OEL frameworks should provide detailed guidance documents and clearly define their protection goals by stating the proportion of the exposed population the OEL aims to cover and the probability with which they intend to provide protection from adverse effects. Harmonisation can be achieved by agreeing on the way to perform the methodological steps for deriving OELs and on common protection goals.  相似文献   
3.
4.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Um Menschen eine informierte Entscheidung über die Teilnahme an Krebsfrüherkennungsuntersuchungen zu ermöglichen,...  相似文献   
5.
6.
Childhood acute lymphoblastic leukaemia (ALL) is suggested to result from a dysregulated immune response to infections in children with a preleukaemic state. Childcare in early life supposedly may protect against childhood ALL by facilitating sufficient exposure to infections to stimulate and ensure normal maturation of the immune system. We assessed the association between childcare attendance before age 2 years and risk of childhood ALL in a register-based cohort study, including all children aged 2 to 14 years born in Denmark during 1991 to 2014 with available childcare information recorded in the Danish Childcare Database (n = 1 116 185). Cox regression was used to estimate hazard ratios (HRs) comparing children enrolled in childcare and children not enrolled before age 2 years. Further, we assessed the association according to age at enrolment, type of childcare facility and specific ALL subtypes. During 10 460 811 person-years of follow-up, 460 children developed ALL at ages 2 to 14 years. Of these, 57 (12.4%) never attended childcare before age 2 years compared with 10.6% in the total cohort. Compared with homecare, childcare attendance before age 2 years was associated with a statistically non-significantly, marginally decreased risk of childhood ALL with adjusted HR = 0.87 (95% confidence interval [CI]: 0.65-1.16). Risk estimates did neither vary statistically significantly by age at enrolment nor by type of childcare facility and also not between childhood ALL subtypes, including frequently prenatally initiated ALL subtypes. Results from this large, nationwide register-based study provided no evidence that childcare attendance in the first years of life protects against childhood ALL.  相似文献   
7.
Accurate modeling of intratumor heterogeneity presents a bottleneck against drug testing. Flexibility in a preclinical platform is also desirable to support assessment of different endpoints. We established the model system, OHC-NB1, from a bone marrow metastasis from a patient diagnosed with MYCN-amplified neuroblastoma and performed whole-exome sequencing on the source metastasis and the different models and passages during model development (monolayer cell line, 3D spheroid culture and subcutaneous xenograft tumors propagated in mice). OHC-NB1 harbors a MYCN amplification in double minutes, 1p deletion, 17q gain and diploid karyotype, which persisted in all models. A total of 80–540 single-nucleotide variants (SNVs) was detected in each sample, and comparisons between the source metastasis and models identified 34 of 80 somatic SNVs to be propagated in the models. Clonal reconstruction using the combined copy number and SNV data revealed marked clonal heterogeneity in the originating metastasis, with four clones being reflected in the model systems. The set of OHC-NB1 models represents 43% of somatic SNVs and 23% of the cellularity in the originating metastasis with varying clonal compositions, indicating that heterogeneity is partially preserved in our model system.  相似文献   
8.
MALT1 is a key mediator of NF-κB signaling and a main driver of B-cell lymphomas. Remarkably, MALT1 is expressed in the majority of pancreatic ductal adenocarcinomas (PDACs) as well, but absent from normal exocrine pancreatic tissue. Following, MALT1 shows off to be a specific target in cancer cells of PDAC without affecting regular pancreatic cells. Therefore, we studied the impact of pharmacological MALT1 inhibition in pancreatic cancer and showed promising effects on tumor progression. Mepazine (Mep), a phenothiazine derivative, is a known potent MALT1 inhibitor. Newly, we described that biperiden (Bip) is a potent MALT1 inhibitor with even less pharmacological side effects. Thus, Bip is a promising drug leading to reduced proliferation and increased apoptosis in PDAC cells in vitro and in vivo. By compromising MALT1 activity, nuclear translocation of c-Rel is prevented. c-Rel is critical for NF-κB-dependent inhibition of apoptosis. Hence, off-label use of Bip or Mep represents a promising new therapeutic approach to PDAC treatment. Regularly, the Anticholinergicum Bip is used to treat neurological side effects of Phenothiazines, like extrapyramidal symptoms.  相似文献   
9.
ABSTRACT

Objectives: The consequences of polypharmacy (intake of ≥ 5 drugs) are diverse, including drug interactions, rising costs and side effects. Risk groups for polypharmacy are multimorbid and chronically ill people, such as patients with multiple sclerosis (MS). MS is the most common neuroimmunological disease in young adults worldwide. We aimed to provide a systematic overview of the current research status regarding frequency and predictors of polypharmacy in MS patients.

Methods: A systematic literature search in the databases PubMed, Cochrane Library and Scopus was carried out according to the PRISMA guidelines. English and German original research articles were included.

Results: Seven studies fulfilled the inclusion criteria of this review, while the research objectives and methods were very heterogenous. The polypharmacy rates in these studies ranged from 15% to 59%. Polypharmacy correlated with comorbidities, increased disability, cognitive deficits, increased hospitalization, higher relapse rate and lower quality of life.

Conclusions: In MS patients, polypharmacy is common and closely associated with health issues. There is a great need for research in this area, especially regarding longitudinal changes in drug utilization. Effective networks between physicians and pharmacists are needed to optimize medication management for patients and to achieve the best possible therapy results.  相似文献   
10.
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