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   2721篇
  免费   213篇
  国内免费   11篇
耳鼻咽喉   21篇
儿科学   101篇
妇产科学   112篇
基础医学   411篇
口腔科学   88篇
临床医学   346篇
内科学   551篇
皮肤病学   117篇
神经病学   153篇
特种医学   42篇
外科学   187篇
综合类   52篇
一般理论   4篇
预防医学   226篇
眼科学   71篇
药学   223篇
中国医学   50篇
肿瘤学   190篇
  2024年   8篇
  2023年   53篇
  2022年   169篇
  2021年   223篇
  2020年   164篇
  2019年   190篇
  2018年   188篇
  2017年   107篇
  2016年   140篇
  2015年   115篇
  2014年   156篇
  2013年   187篇
  2012年   245篇
  2011年   233篇
  2010年   115篇
  2009年   81篇
  2008年   113篇
  2007年   103篇
  2006年   87篇
  2005年   90篇
  2004年   59篇
  2003年   31篇
  2002年   30篇
  2001年   4篇
  2000年   1篇
  1999年   6篇
  1998年   2篇
  1997年   3篇
  1996年   2篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1991年   1篇
  1990年   1篇
  1988年   5篇
  1987年   7篇
  1986年   2篇
  1985年   5篇
  1984年   2篇
  1980年   1篇
  1979年   4篇
  1977年   1篇
  1976年   1篇
  1973年   2篇
  1936年   1篇
排序方式: 共有2945条查询结果,搜索用时 15 毫秒
21.
Immunotherapy has been recently considered as a promising alternative for cancer treatment. Indeed, targeting of immune checkpoint (ICP) strategies have shown significant success in human malignancies. However, despite remarkable success of cancer immunotherapy in pancreatic cancer (PCa), many of the developed immunotherapy methods show poor therapeutic outcomes in PCa with no or few effective treatment options thus far. In this process, immunosuppression in the tumor microenvironment (TME) is found to be the main obstacle to the effectiveness of antitumor immune response induced by an immunotherapy method. In this paper, the latest findings on the ICPs, which mediate immunosuppression in the TME have been reviewed. In addition, different approaches for targeting ICPs in the TME of PCa have been discussed. This review has also synopsized the cutting-edge advances in the latest studies to clinical applications of ICP-targeted therapy in PCa.KEY WORDS: Immune checkpoint, Pancreatic cancer, Tumor microenvironment, Immunotherapy, Clinical development  相似文献   
22.
23.
Medicinal plants have been widely investigated for their various effects. Dracocephalum kotschyi Boiss (Labiatae) is used in Iranian traditional medicine for the treatment of rheumatoid diseases. The inhibitory effect of D. kotschyi on the lectin-induced cellular immune response has been demonstrated previously. In this study, mitogen-treated lymphocytes were exposed to the extract of D. kotschyi and analysed for the induction of apoptosis using flow cytometry and gel electrophoresis. The data obtained indicated a dose-dependent increase of cells in the sub-G1 phase of cell cycle. Study of internucleosomal DNA fragmentation showed a typical DNA laddering in agarose gels. A bioactivity-guided fractionation assay to find the active components responsible for the inhibitory effect of D. kotschyi on mitogen-induced lymphocyte proliferation led to the isolation of calycopterin from the ethyl acetate extract of D. kotschyi. Its structure was identified by spectroscopic methods including( 1)H-NMR, (13)C-NMR, MS and UV spectra. Calycopterin inhibited lymphocyte proliferation in a dose-dependent manner with an IC(50) value of 1.7 microg/mL. In conclusion, the results of this study suggest that D. kotschyi extract has the capacity to induce apoptosis in the lymphocytes and that isolated calycopterin is responsible for the inhibitory effect of D. kotschyi on lymphocyte proliferation.  相似文献   
24.
ObjectiveCOVID-19 has recently emerged as a serious threat to global health. This study examined the laboratory investigations of patients with COVID-19, with an emphasis on liver enzymes.MethodsThis retrospective, single-center study was performed on patients with COVID-19 who were admitted to Imam Reza Hospital, Iran from March 2020 to February 2021. Laboratory tests included a complete blood cell count, white blood cell (WBC) count, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), lymphocyte/monocyte ratio, and levels of aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase. Patient survival was among the outcome measures investigated in association with laboratory findings.ResultsWe enrolled 77 patients with COVID-19 and 63 healthy controls. In comparison with the control group, patients with COVID-19 showed COVID-19 increased ALT, WBC, neutrophils, NLR, and PLR, and decreased platelet counts and lymphocytes.ConclusionAlthough elevated levels of AST, NLR, PLR, and LMR were found in patients with COVID-19, they were not linked to mortality. Given the presence of AST in other tissues, the influence of SARS-CoV-2 on the liver should be interpreted with caution.  相似文献   
25.
BackgroundPregnancy is a major concern among women with the sickle cell disease (SCD), and it is associated with increased adverse outcomes. The aim of the present meta-analysis is to report the fetomaternal outcomes in different sickle cell genotypes.MethodsIn this systematic review and meta-analysis, a comprehensive search of databases and search engines such as PubMed, Scopus, Web of Science, ProQuest, Cochrane Library, Science Direct and Google Scholar were performed. Any observational studies that had compared at least one outcome such as maternal outcomes, fetal outcomes, and morbidity between two groups of pregnant women with different types of sickle cell genotypes and pregnant women without SCD were evaluated.ResultsA total number of 9,827 pregnant women with SCD were examined. The results showed that pregnancy in SCD increased the risk of adverse outcomes for the mothers (including postpartum hemorrhage, prematurity, pregnancy-induced hypertension, pre-eclampsia, eclampsia, cesarean section, lower segment cesareansection, maternal death), fetus (including live births, low birth weight, intrauterine growth restriction, APGAR score at 5 min <7, stillbirth, neonatal death, perinatal mortality, acute fetal distress, intrauterine fetal death) and morbidity among the SCD(severe anemia, urinary tract infection, blood transfusion, painful crisis, acute chest syndrome, vaso-occlusive crises).ConclusionAccording to the results of this meta-analysis, pregnancy in the SCD is associated with an increased risk of maternal outcomes, fetal outcomes, and morbidity among SCD patients with different genotypes. Pregnancy in sickle cell hemoglobinopathies needs careful multidisciplinary management and cautious caring so as to decrease maternal and fetal morbidity and mortality.  相似文献   
26.
Sarcoidosis is a multisystem inflammatory disorder of unknown cause. It most commonly affects the pulmonary system but can also affect the musculoskeletal system, albeit less frequently. In patients with sarcoidosis, rheumatic involvement is polymorphic. It can be the presenting symptom of the disease or can appear during its progression. Articular involvement is dominated by nonspecific arthralgia, polyarthritis, and Löfgren''s syndrome, which is defined as the presence of lung adenopathy, arthralgia (or arthritis), and erythema nodosum. Skeletal manifestations, especially dactylitis, appear mainly as complications of chronic, multiorgan sarcoidosis. Muscle involvement in sarcoidosis is rare and usually asymptomatic. The diagnosis of rheumatic sarcoidosis is based on X-ray findings and magnetic resonance imaging findings, although the definitive diagnosis is made by anatomopathological study of biopsy samples. Musculoskeletal involvement in sarcoidosis is generally relieved with nonsteroidal anti-inflammatory drugs or corticosteroids. In corticosteroid-resistant or -dependent forms of the disease, immunosuppressive therapy, such as treatment with methotrexate or anti-TNF-α, is employed. The aim of this review was to present an overview of the various types of osteoarticular and muscle involvement in sarcoidosis, focusing on their diagnosis and management.  相似文献   
27.
28.
29.
BackgroundInvolvement of distal fibula by benign aggressive and malignant tumors usually necessitates resection of the involved segment of fibula. Numerous techniques have been proposed to reconstruct the ankle joint after this procedure, which can result in complications. We introduce reconstruction of ankle joint by fibular osteoarticular allograft.MethodsReconstruction of the distal fibula after wide resection of tumor was carried out in four patients. There were two cases of Ewing sarcoma, one case of osteosarcoma and one giant cell tumor. After wide resection of tumor, we reconstructed the lateral side of the ankle joint by osteoarticular fibular allograft, which was applied and internally fixed with semitubular plate and screws. In the follow up period, we did assessment of complications, pain and ankle joint instability.ResultsThe mean age of our patients was 24.2 years (12–31). The mean follow-up was 3.2 years (1.5–6.7). In follow up visits there were no signs of infection or wound healing problems. Union was achieved in all patients.ConclusionIn cases of benign aggressive and malignant tumors involving the distal fibula, we can recommend resection of the distal fibula and reconstruction of the ankle with osteoarticular allograft of the distal fibula.Level of evidenceCase series level IV.  相似文献   
30.
We aimed to determine the prevalence and determinants of depression using mobile based mental health Global Action Programme Intervention guide (mhGAP-IG) in remote health care settings where most priority mental health problems are managed by non-mental health specialists and evaluate the feasibility of the application. Adult patients were recruited from four rural public health facilities in Kenya using systematic random sampling and screened for depression. There were no missing items since the application prevented saving of data unless all the items were answered. The prevalence of depression was 25% with suicidal behavior being the most significant comorbid problem. Older age, personal and a family history of a mental disorder were significantly correlated with depression. Exploring the use of health-related mobile applications in identification of priority mental health problems is useful notably in low-resource settings; and also forms a basis for prevention of mental disorders and intervention at acute stages.  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