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   409篇
  免费   21篇
  国内免费   15篇
耳鼻咽喉   7篇
儿科学   32篇
妇产科学   7篇
基础医学   59篇
口腔科学   7篇
临床医学   41篇
内科学   64篇
皮肤病学   19篇
神经病学   8篇
特种医学   43篇
外科学   33篇
综合类   35篇
预防医学   17篇
眼科学   6篇
药学   22篇
肿瘤学   45篇
  2023年   2篇
  2022年   2篇
  2021年   3篇
  2020年   3篇
  2019年   5篇
  2018年   6篇
  2017年   7篇
  2016年   6篇
  2015年   9篇
  2014年   11篇
  2013年   15篇
  2012年   10篇
  2011年   11篇
  2010年   17篇
  2009年   23篇
  2008年   13篇
  2007年   16篇
  2006年   16篇
  2005年   11篇
  2004年   3篇
  2003年   5篇
  2002年   7篇
  2001年   9篇
  2000年   8篇
  1999年   15篇
  1998年   35篇
  1997年   28篇
  1996年   14篇
  1995年   14篇
  1994年   15篇
  1993年   13篇
  1992年   7篇
  1991年   6篇
  1990年   3篇
  1989年   7篇
  1988年   5篇
  1987年   6篇
  1986年   3篇
  1985年   12篇
  1984年   2篇
  1983年   8篇
  1982年   4篇
  1981年   5篇
  1980年   5篇
  1978年   2篇
  1977年   3篇
  1976年   4篇
  1975年   3篇
  1967年   2篇
  1955年   1篇
排序方式: 共有445条查询结果,搜索用时 15 毫秒
91.
92.
93.
OBJECTIVE: Three founder alleles of the CHEK2 gene have been associated with predisposition to a range of cancer types in Poland. Two founder alleles (1100delC and IVS2 + 1G >A) result in a truncated CHEK2 protein and the other is a missense substitution, leading to the replacement of a threonine with an isoleucine (I157T). METHODS: To establish if these variants play a role in the etiology of ovarian tumors, we genotyped 1108 Polish women with various types of ovarian tumors and 4000 controls for the three CHEK2 variants. We included 539 Polish women with benign ovarian cystadenomas, 122 women with borderline ovarian malignancies and 447 women with invasive ovarian cancer. RESULTS: Positive associations were seen with the CHEK2 I157T missense variant and ovarian cystadenomas (OR = 1.7; P = 0.005), with borderline ovarian cancers (OR = 2.6; P = 0.002) and with low-grade invasive cancers (OR = 2.1; P = 0.04). There was no association with ovarian cancer of high grade (OR = 1.0). The association between the I157T missense variant was then confirmed in a second sample of Russian patients with borderline ovarian cancers (OR = 2.7; P = 0.06). CONCLUSION: These data indicate that CHEK2 variants may predispose to a range of ovarian tumor types of low malignant potential, but not to aggressive cancers.  相似文献   
94.
Esophagectomy,the surgical removal of all or part of the esophagus,is a surgical procedure that is associated with high morbidity and mortality.Pulmonary complications are an especially important postoperative problem.Therefore,many perioperative strategies to prevent pulmonary complications after esophagectomy have been investigated and introduced in daily clinical practice.Here,we review these strategies,including improvement of patient performance and technical advances such as minimally invasive surgery that have been implemented in recent years.Furthermore,interventions such as methylprednisolone,neutrophil elastase inhibitor and epidural analgesia,which have been shown to reduce pulmonary complications,are discussed.Benefits of the commonly applied routine nasogastric decompression,delay of oral intake and prophylactic mechanical ventilation are unclear,and many of these strategies are also evaluated here.Finally,we will discuss recent insights and new developments aimed to improve pulmonary outcomes after esophagectomy.  相似文献   
95.
Virtually all known tumor predisposing genes have been identified via the analysis of familial cancer cases. Here we argue that this approach is likely to miss recessively acting cancer genes and suggest the analysis of family history-negative patients with multiple primary malignancies for identifying homozygous at-risk genotypes. We performed calculations showing that the homozygous carriers of rare recessive cancer predisposing alleles are unlikely to report a family history of the disease. We further revealed that the c.2515_2519delAAGTT homozygous mutation in a Holliday junction resolvase, GEN1, was overrepresented in women with bilateral breast cancer (BC) as compared to healthy controls [11/360 (3.1 %) vs. 18/1305 (1.4 %); odds ratio (OR) = 2.25 (1.02–4.75); p = 0.031], although this trend was not maintained in unilateral BC patients [23/1851 (1.2 %)]. Noticeably, presence of biallelic c.2515_2519delAAGTT mutation was associated with the absence of BC in mother both in bilateral and unilateral BC cases [7/239 (3.0 %) vs. 0/41 (0 %) and 21/1,558 (1.3 %) vs. 0/215 (0 %), respectively; Mantel–Haenszel p = 0.041]. Thus, this study suggests that identification of dominant and recessive cancer predisposing genes may require distinct study groups.  相似文献   
96.

Background

Cutaneous manifestations are early and easily identifiable markers of human immunodeficiency virus (HIV) infection. They can help in predicting severity and progress of the disease and can be correlated well with CD4 counts. This study was undertaken to study the cutaneous manifestations of HIV infection and to correlate them with CD4 counts. It also aimed to study the changing spectrum of these manifestations and describe cutaneous manifestations seen in advanced disease.

Method

A total of 234 HIV-positive patients not on anti-retroviral therapy, who attended the outpatient department or were admitted as inpatients at Military Hospital, Shillong during the period between May 2008 and October 2009 were included. Cutaneous, mucosal, and genitourinary manifestations in these patients were studied in detail and were correlated with CD4 counts.

Results

Infections were the most common group of mucocutaneous manifestations, while onychomycosis was the commonly observed individual manifestation. A different set of cutaneous markers for advanced HIV disease was observed and new parameters for therapy were also arrived at.

Conclusion

Specific morphological variants of cutaneous markers may provide a better clue to early diagnosis of HIV and can help in diagnosing advanced stages of the disease. Fresh cutaneous markers are required for indicating cut-off levels of CD4 count at 350/μL for starting therapy.  相似文献   
97.
98.
HPLC分离测定格列齐特片及其有关物质   总被引:6,自引:0,他引:6  
目的:建立新的HPLC法分离测定格列齐特征及其有关物质。方法:色谱条件为:Shim-Pack VP-ODS(5um,150mm*4.6mm i.d.)色谱柱;甲醇-0.02mol/L磷酸(用三乙胺调节PH至3.5),(70:30)为流动相;检测波长为229nm。结果:在50-300ug;/ml的浓度范围内线性关系良好。r=0.9999(n=6);平均回收率为100.5%,RSD为0.17%(n=6),重复进样RSD为0.12%(n=6),格列齐特及其有关物质得到基线分离。结论:本法简便,快速,准确,适用于格列齐特及其制剂的质量控制。  相似文献   
99.
Modeling the growth of Yersinia enterocolitica in donated blood   总被引:4,自引:0,他引:4  
BACKGROUND: Sepsis and death subsequent to the transfusion of blood containing Yersinia enterocolitica is an increasing problem. The organisms probably originate from bacteremia in the donor and can subsequently multiply at low temperature. STUDY DESIGN AND METHODS: Reported here are experiments with a strain of Y. enterocolitica associated with a case of transfusion-associated bacteremia. RESULTS: It was found that the rapid early killing of Y. enterocolitica injected into donated blood does not require viable phagocytes and can be explained by complement-mediated killing. Complement resistance in Y. enterocolitica is known to be plasmid-coded. It is expressed at 37 degrees C, but not at 20 degrees C, and is favored by calcium-deficient culture media. Y. enterocolitica organisms induced to express complement resistance were still killed in donated blood, though the initial rate was slower. Such organisms multiplied in plasma at 37 degrees C, but were killed after 6 hours of incubation at 20 degrees C, presumably because complement resistance genes are switched off at this temperature. CONCLUSION: This experiment is thought to reflect the natural history of Y. enterocolitica contamination of blood, in which complement-resistant organisms in the donor blood encounter lower temperatures after donation. These observations suggest that the practice of plasma depletion may have contributed to the increased incidence of mortality due to Y. enterocolitica contamination of donated blood.  相似文献   
100.
OBJECTIVE: To compare the incidence, symptomatology and course of mastocytosis with onset in childhood and in adults. DESIGN: Retrospective study of 101 patients with mastocytosis who were referred from 1980 to 1998. PATIENTS: Medical records of 65 cases of mastocytosis with onset in childhood and 36 in adulthood were analysed. The clinical course was assessed in a subgroup consisting of 33 subjects with childhood onset who were followed up until at least adolescence and 12 subjects with adult onset who were followed up for at least 10 years. RESULTS: The onset of the disease occurred before the age of 2 years in 50% and between the ages of 2 and 15 years in 14% of cases (childhood onset). In 36% of patients onset occurred at the age of 16 years and older (adult onset). An incidence peak of 60% was noted in the first year of life. Mast cell-mediated symptoms were not experienced by 21 of 36 adult onset mastocytosis patients nor by 27 of 65 childhood onset mastocytosis patients. Complete resolution was observed in five of 33 children. The majority of childhood onset cases (21 of 33) showed some improvement. Complete resolution was achieved in three of 12 adults. The majority of the remaining adults (eight of 12) showed no improvement. CONCLUSIONS: We confirm the incidence of onset of mastocytosis previously reported in the literature. We conclude that childhood onset mastocytosis is much less transitory than generally is assumed, although improvement occurs in the majority of cases. Symptomatology and clinical course of adult onset mastocytosis is less severe than suggested in the literature.  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