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   7322篇
  免费   446篇
  国内免费   21篇
耳鼻咽喉   34篇
儿科学   211篇
妇产科学   193篇
基础医学   1225篇
口腔科学   166篇
临床医学   690篇
内科学   1557篇
皮肤病学   287篇
神经病学   686篇
特种医学   213篇
外科学   616篇
综合类   45篇
一般理论   3篇
预防医学   690篇
眼科学   69篇
药学   536篇
中国医学   26篇
肿瘤学   542篇
  2023年   60篇
  2022年   92篇
  2021年   159篇
  2020年   166篇
  2019年   210篇
  2018年   217篇
  2017年   167篇
  2016年   201篇
  2015年   233篇
  2014年   288篇
  2013年   368篇
  2012年   560篇
  2011年   558篇
  2010年   321篇
  2009年   266篇
  2008年   463篇
  2007年   482篇
  2006年   465篇
  2005年   435篇
  2004年   369篇
  2003年   354篇
  2002年   307篇
  2001年   85篇
  2000年   70篇
  1999年   61篇
  1998年   64篇
  1997年   50篇
  1996年   46篇
  1995年   36篇
  1994年   30篇
  1993年   26篇
  1992年   32篇
  1991年   40篇
  1990年   39篇
  1989年   24篇
  1988年   29篇
  1987年   21篇
  1986年   29篇
  1985年   27篇
  1983年   15篇
  1982年   26篇
  1981年   22篇
  1979年   21篇
  1978年   17篇
  1977年   14篇
  1976年   18篇
  1974年   16篇
  1971年   16篇
  1967年   15篇
  1966年   13篇
排序方式: 共有7789条查询结果,搜索用时 0 毫秒
21.
Facially amphiphilic polymers carrying cationic and hydrophobic groups on the same repeat unit have shown promising antimicrobial activity and biocompatibility, yet they are prone to suffer from protein adhesion which may induce biofilm formation. To overcome this problem, poly(diitaconate)-based copolymers with cationic/hydrophobic and protein-repellent/charge-neutral repeat units are synthesized. The bioactivity profile of surface-attached polymer networks made from these copolymers depends on the ratio of the cationic and charge-neutral repeat units. In all cases, the protein adhesion is substantially reduced compared to purely cationic polymers. At a 50:50 ratio, the polymer coatings are partially protein-repellent and antimicrobial, yet slightly cell toxic. At an intermediate composition of 30:70, they are still antimicrobial and the cell compatibility is substantially improved. The long-term stability of these materials still has to be determined to judge their suitability for medical applications.  相似文献   
22.
Polish abortions     
Rich V 《Lancet》1994,343(8905):1090
  相似文献   
23.
Chromosome 11q13 markers and D-type cyclins in breast cancer   总被引:7,自引:0,他引:7  
Summary One in six primary human breast cancers has DNA amplification centered on the cyclin D1 gene (CCND1) on chromosome 11q13. This genetic abnormality is preferentially associated with estrogen-receptor positive tumors and may define a sub-class of patients with an adverse prognosis. AlthoughCCND1 has the credentials of a cellular oncogene, being a target for chromosomal translocation and retroviral integration, the 11q13 amplicon encompasses several other markers andCCND1 is not the only candidate for the key gene on the amplified DNA. To assess their relative importance, we have constructed a physical map of the amplified DNA and compared the extent and frequency of amplification across the region. Since it is likely that the gene providing the selective force for amplification will be expressed at elevated levels, we have also examined expression of both RNA and protein. By these criteria, cyclin D1 remains the strongest candidate for the key oncogene on the amplicon and we are currently investigating the functional consequences of its over-expression.Presented by Gordon Peters at the 16th Annual San Antonio Breast Cancer Symposium, San Antonio TX, USA, November 4, 1993; Minisymposium on Molecular Genetics in Breast Cancer.  相似文献   
24.
25.
Octreotide as first-line treatment for women with metastatic breast cancer   总被引:1,自引:0,他引:1  
Summary Octreotide is a synthetic somatostatin analogue which has shown inhibitory activity against human breast cancer cells in culture. Ten patients with metastatic breast cancer and no prior hormonal therapy exposure received octreotide at 150 g subcutaneously thrice daily. No objective responses were observed and the median time to treatment failure was short at 57 days.  相似文献   
26.
BACKGROUND: The longer term respiratory effects of massive inhalational exposure of textile printing sprayers to Acramin (the "Ardystil syndrome") are not well established. METHODS: A 12 month follow up of 27 heavily exposed textile sprayers was performed. RESULTS: Twenty one patients experienced cough, 18 dyspnoea, and 17 nose bleeding at initial exposure, with histological evidence of organising pneumonia in 13 cases, radiological abnormalities detected by computed tomographic scanning in 20 cases, and diminution of diffusion capacity to below 80% of predicted in seven cases. At one year after exposure symptoms persisted in 15 cases, radiological alterations in six, and diffusion capacity was reduced in nine. CONCLUSIONS: Whilst most of our patients showed improvement at one year, evidence of persistent lung involvement was present in an appreciable minority of exposed cases.  相似文献   
27.
We report a case of primary intraosseous pleiomorphic rhabdomyosarcoma located in the pelvis of a 21-year-old woman followed for 4 years. The lytic tumor involved the acetabulum and the isthma with moderate extension to soft tissue. First line chemotherapy was unable to arrest tumor progression. Hemipelvectomy with saddle prosthesis reconstruction was performed, but septic complications dictated a secondary inter-ilio-abdominal amputation. Recurrence-free remission was achieved for 4 years, suggesting this was indeed a primary tumor. Primary intraosseous rhabdomyosarcomas are exceptional. Bone localizations generally suggest metastasis from a primary tumor often situated in an intraperitoneal localization. When search for a primary tumor is negative, intraosseous lesions can be considered as primary tumors warranting curative treatment. Radical surgical resection is recommended within the framework of a multidiscipinary management protocol associating radiotherapy and chemotherapy to improve prognosis.  相似文献   
28.
Cytochrome P4502E1 (CYP2E1) plays an important role in ROS production thus favouring accelerated membrane lipid peroxidation. This isoform is strongly expressed in the liver but it can be also found in lymphocytes. As such, lymphocyte may provide a non-invasive accessible pool for screening CYP2E1 expression in man. We have, therefore, analysed CYP2E1 expression and activity in lymphocyte microsomes from 12 healthy controls, 11 type 1 and 12 type 2 diabetic subjects by using Western blot and enzymatic activities. Immunoblotting did not show difference among CYP2E1 protein bands in controls, type 1 and type 2 diabetics. To assess CYP2E1 activity we used the 7-ethoxy-4-trifluoromethylcoumarin (7-EFC), as a fluorescent substrate. The rate of deethylation of 7-EFC from controls did not differ from type 1 and type 2 diabetic subjects. The lack of any difference in CYP2E1 activity also was confirmed by the NADPH-dependent microsomal lipid peroxidation CCL4-induced assay showing similar peroxidation rates among controls and diabetic subjects. The results show that CYP2E1 expression/activity in lymphocytes is not enhanced in diabetes.  相似文献   
29.
30.
ObjectivesObstructive sleep apnea (OSA) is a common condition closely related to obesity, insulin resistance, dyslipidemia, and cardiovascular disease. The aim of this study was to explore the possible relationship between OSA and proprotein convertase subtilisin/kexin type 9 (PCSK9).MethodsFull-night polysomnography was performed on 150 participants who were divided into three groups: controls, OSA patients on statin therapy, and OSA patients not on statin therapy. Biochemical markers, plasma low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subclasses, and PCSK9 were determined.ResultsPCSK9 was highest in OSA patients on statins compared to the control group and to OSA patients not on statins (p = 0.036 and p = 0.039, respectively), after adjustment for body mass index (BMI). LDL diameter was greater in OSA patients not on statins compared to OSA patients on statins (p = 0.032). PCSK9 was highest in the group of patients with all three risk factors (diagnosed OSA, statins, BMI ≥25 kg/m<sup>2</sup>) compared to groups with no, one, and two risk factors (p = 0.031, p = 0.001, and p = 0.029, respectively). Presence of OSA, statin therapy, and BMI ≥25 kg/m<sup>2</sup> when combined were independently associated with higher levels of PCSK9 when adjusted for antihypertensive therapy, small dense LDL, and HDL 3c subclass (odds ratio = 2.849; interquartile range [1.026–7.912], p = 0.044).ConclusionStatin therapy was closely related to PCSK9. OSA along with obesity and statin use induces elevation of PCSK9.  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