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   17346篇
  免费   1032篇
  国内免费   78篇
耳鼻咽喉   104篇
儿科学   412篇
妇产科学   435篇
基础医学   2531篇
口腔科学   544篇
临床医学   1398篇
内科学   4089篇
皮肤病学   346篇
神经病学   1632篇
特种医学   372篇
外国民族医学   2篇
外科学   1598篇
综合类   435篇
一般理论   7篇
预防医学   1647篇
眼科学   390篇
药学   1278篇
中国医学   94篇
肿瘤学   1142篇
  2023年   113篇
  2022年   295篇
  2021年   484篇
  2020年   286篇
  2019年   429篇
  2018年   572篇
  2017年   325篇
  2016年   440篇
  2015年   483篇
  2014年   666篇
  2013年   826篇
  2012年   1296篇
  2011年   1367篇
  2010年   669篇
  2009年   628篇
  2008年   1115篇
  2007年   1182篇
  2006年   1071篇
  2005年   955篇
  2004年   827篇
  2003年   799篇
  2002年   710篇
  2001年   282篇
  2000年   259篇
  1999年   238篇
  1998年   145篇
  1997年   123篇
  1996年   110篇
  1995年   80篇
  1994年   85篇
  1993年   89篇
  1992年   143篇
  1991年   120篇
  1990年   110篇
  1989年   117篇
  1988年   89篇
  1987年   89篇
  1986年   98篇
  1985年   70篇
  1984年   63篇
  1983年   47篇
  1982年   40篇
  1981年   46篇
  1980年   38篇
  1979年   51篇
  1978年   26篇
  1976年   27篇
  1974年   37篇
  1972年   27篇
  1966年   25篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
81.
Quality of Life Research - Neck pain tends to persist for periods of 1 to 4 years of follow-up in adolescents, and a high percentage of them report disability. However, studies assessing...  相似文献   
82.
Maternal and Child Health Journal - This study aims to explore association between maternal depressive symptoms and infant feeding practice at hospital discharge. Data were obtained from a birth...  相似文献   
83.
During the peri-coronavirus disease 2019 pandemic, the need of special care has raised, not only for our patients but also for health care workers. These needs are different regarding the procedure and the approach performed. This is a dynamic review in the use of robotics and transanal approaches for colorectal diseases. We searched PubMed and KSREvidence.com for studies related to coronavirus disease and robotic surgery/transanal mesorectal excision/transanal surgery(primary and systematic reviews). From 147 results in PubMed, 11 were selected for full text screening, and 11 were included in this paper. From 3 results in KSREvidence, no relevant systematic reviews were identified. We also checked the references in identified papers for further relevant studies. European Society of Coloproctology guidelines were including as part of the recommendations available. Robotic and transanal MIS can be performed safely during the pandemic, but particular characteristics of these procedure need to be taken into consideration.  相似文献   
84.
Nucleotide sequences coding for the full-length envelope (E) glycoprotein gene of dengue virus type 4 was amplified using an RT-PCR method from infected C6/36 cells and cloned into pPROEx-Hta expression vector. The expression of the recombinant E protein in Escherichia coli was confirmed by Western blot using a polyclonal anti-dengue polyclonal antibody. The His-tagged fusion protein was obtained from the bacterial cellular extracts in almost pure form by immobilized metal affinity chromatography and the recombinant protein retained its ability to bind to 40 and 45 kDa proteins, previously described as putative receptors for dengue virus in C6/36 cells. To purify the 40 and 45 kDa molecules, a total protein extract from C6/36 cells was passed through an affinity chromatography column using immobilized recombinant E protein. After washing with isotonic buffer, elution was accomplished using a high salt buffer. The two proteins obtained, with molecular weights of 40 and 45 kDa, were recognized by dengue 4 virus, in virus overlay protein binding assay. This procedure allows further characterization of molecules that could be involved in dengue binding and entry.  相似文献   
85.
Electron microscopy has been the ‘gold standard’ of spatial resolution for studying the structure of the cell nucleus. Electron spectroscopic imaging (ESI) offers advantages over conventional transmission electron microscopy by eliminating the need for heavy-atom contrast agents. ESI also provides mass-dependent and element-specific information at high resolution, permitting the distinguishing of structures that are primarily composed of protein, DNA, or RNA. The technique can be applied to understand the structural consequences of epigenetic modifications, such as modified histones, on chromatin fiber morphology. ESI can also be applied to elucidate the multifunctional behavior of subnuclear ‘organelles’ such as the nucleolus and promyelocytic leukemia nuclear bodies. The authors dedicate this paper to the memory of Ying Ren (1961–2007). We all benefited from knowing her. Our research advanced through the technical creativity she provided.  相似文献   
86.
Summary An immunoconjugate composed of natural interferon (nIFN) bound in a noncleavable fashion to a monoclonal antibody (MoAb) recognizing a breast epithelial membrane mucin (Mc5) was used to treat xenografts of a human mammary carcinoma cell line (MCF-7) growing in nude mice. The immunoconjugate (nIFN/Mc5) was administered as 20 intralesional (i.l.) injections to 1 of 2 xenografts in each animal. It was found that nIFN/Mc5 produced a significant enhancement of the growth inhibitory actions of nIFN on the injected tumors. Further enhancement was obtained when nIFN or nIFN together with Mc5 (at a dose 10 times larger than that present in nIFN/Mc5) were added to the immunoconjugate. Biodistribution experiments showed that the uptake of125I-nIFN/Mc5 by the tumors was greater and its elimination slower than for125I-nIFN alone or conjugated to irrelevant mouse IgG1. In addition, the immunoconjugate up-regulated the antigenic expression of a breast epithelial membrane mucin by the carcinoma cells, an up-regulation which was not significantly different from that produced by nIFN alone. The contralateral noninjected tumors exposed to systemic levels of the immunoconjugate showed an enhancement of antitumor effects, but to a lesser extent than the injected tumors. These findings suggest that the enhancement of the growth inhibitory action of the immunoconjugate was related to the specific binding of Mc5 which targeted the IFN to the carcinoma cells and impeded its elimination. It is likely that the targeting was favored by the IFN-mediated up-regulation of antigenic expression by the carcinoma cells, thereby producing a cascade of interrelated effects. The results of this study point out the feasibility and potential usefulness of IFN treatment by means of immunoconjugates as well as the worth of pursuing and improving this form of therapy.  相似文献   
87.
Formulation of business plans by National Health hospitals requires information on likely demands for the services they provide. Two cohorts of patients admitted to the Nottingham hospitals in 1983 and 1989 with suspected myocardial infarction were sampled to determine the workload implications due to initial in-hospital tests, subsequent readmission and outpatient investigations. The results show that attendance in the first year after discharge related principally to cardiac problems, while in subsequent years non-cardiac problems predominated. An estimation of the total workload, based upon 1,000 patients admitted in 1989, suggests that demands for hospital services in the following year include over 4,000 electrocardiographs, 1,400 chest X-rays and 18,000 laboratory tests, and only 118 exercise tests and 37 cardiac catheterisations. Admission with suspected myocardial infarction makes great demand on hospital services in the year after discharge. Any change in practice, which increases the potential demand for cardiac investigations, could have important financial implications for Nottingham hospitals.  相似文献   
88.
A study is made in the Intensive Care Unit of "José L. Miranda" Provincial Pediatric Teaching Hospital in Santa Clara in order to know the sequence with which the father occupies the place of the mother in the care of hospitalized children. With this objective, 54 male companions are surveyed in the first trimester of 1987. The prevailing occupational profile was that of worker. A higher number of the respondents were between 17 and 25 years of age. The school level of secondary school prevailed among patient companions. Most of them reported no economic inconveniences during the child's disease. The desire to remain at the bedside and the inability of the mother to do so were the major reasons for their stay. The advantages recognized by the nursing personnel in male companions are made known.  相似文献   
89.
The aim of the present study was to investigate the nature and prevalence of nonspecific somatic symptoms, pain and catastrophizing in children with Heritable Connective Tissue Disorders (HCTD), and to determine their association with disability. This observational, multicenter study included 127 children, aged 4–18 years, with Marfan syndrome (MFS) (59%), Loeys-Dietz syndrome (LDS) (8%), Ehlers-Danlos syndromes (EDS) (12%) and hypermobile Ehlers-Danlos syndrome (hEDS) (23%). The assessments included the Children's Somatization Inventory or parent proxy (CSI, PCSI), pain visual-analogue scale (VAS), SUPERKIDZ body diagram, Pain Catastrophizing Scale Child or parent proxy (PCS-C, PCS-P) and Childhood Health Assessment Questionnaire (CHAQ-30). Data from children aged ≥8 years were compared to normative data. In children ≥ 8 years (n = 90), pain was present in 59%, with a median of 4 (IQR = 3–9) pain areas. Compared to normative data, the HCTD group reported significantly higher on the CSI (p ≤ 0.001, d = 0.85), VAS pain intensity (p ≤ 0.001, d = 1.22) and CHAQ-30 (p ≤ 0.001, d = 1.16) and lower on the PCS-C (p = 0.017, d = −0.82) and PCS-P (p ≤ 0.001, d = −0.49). The intensity of nonspecific somatic symptoms and pain explained 45% of the variance in disability (r2 = 0.45 F(2,48) = 19.70, p ≤ 0.001). In children ≤ 7 years (n = 37), pain was present in 35% with a median of 5(IQR = 1–13) pain areas. The mean(SD) VAS scores for pain intensity was 1.5(2.9). Functional disability was moderately correlated to the number of pain areas (r = 0.56, p ≤ 0.001), intensity of nonspecific somatic symptoms (r = 0.63, p ≤ 0.001) and pain (r = 0.83, p ≤ 0.001). In conclusion, this study supports the need for comprehensive assessment of nonspecific somatic symptoms, pain, and disability in children with HCTD to allow tailored treatment.  相似文献   
90.
Nonpuerperal breast infection   总被引:1,自引:1,他引:0       下载免费PDF全文
Objective: We undertook a microbiological study of purulent specimens from women with symptomatic breast abscesses.Methods: Fifty-one purulent samples were collected in 2 periods (December 1991-April 1992 and January 1994-June 1994) from nonpuerperal breast abscesses in 44 patients attending our hospital.Results: One of the most frequently isolated microorganisms was Proteus mirabilis (9 patients, 20.4%), present as a pure culture in all but 1 specimen (isolated together with Peptostreptococcus spp.). Staphylococcus aureus was isolated in 10 specimens, 6 of which were post-tumorectomy abscesses. Polymicrobial anaerobic flora were isolated in 11 specimens (21.5%); Staphylococcus epidermidis in 4 (8%); and Streptococcus milleri,Alcaligenes sp., and mixed aerobic-anaerobic flora in 1 specimen each. The 7 remaining samples (13.7%) were negative bacteriological cultures.Conclusions: We draw attention to the frequent isolation of P. mirabilis in recurrent and torpid breast abscesses in 4 women in whom surgery was necessary in addition to antibiotic treatment.  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