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   6729篇
  免费   345篇
  国内免费   37篇
耳鼻咽喉   210篇
儿科学   155篇
妇产科学   219篇
基础医学   932篇
口腔科学   370篇
临床医学   511篇
内科学   1533篇
皮肤病学   115篇
神经病学   511篇
特种医学   141篇
外科学   1059篇
综合类   28篇
预防医学   526篇
眼科学   145篇
药学   341篇
中国医学   35篇
肿瘤学   280篇
  2023年   51篇
  2022年   112篇
  2021年   205篇
  2020年   120篇
  2019年   200篇
  2018年   207篇
  2017年   125篇
  2016年   173篇
  2015年   240篇
  2014年   312篇
  2013年   346篇
  2012年   534篇
  2011年   599篇
  2010年   350篇
  2009年   269篇
  2008年   454篇
  2007年   474篇
  2006年   451篇
  2005年   389篇
  2004年   349篇
  2003年   290篇
  2002年   266篇
  2001年   81篇
  2000年   71篇
  1999年   61篇
  1998年   45篇
  1997年   30篇
  1996年   22篇
  1995年   17篇
  1994年   18篇
  1993年   14篇
  1992年   20篇
  1991年   29篇
  1990年   20篇
  1989年   15篇
  1988年   17篇
  1987年   13篇
  1986年   13篇
  1985年   8篇
  1984年   12篇
  1983年   8篇
  1982年   10篇
  1981年   9篇
  1980年   13篇
  1979年   9篇
  1978年   6篇
  1976年   5篇
  1974年   4篇
  1973年   6篇
  1970年   4篇
排序方式: 共有7111条查询结果,搜索用时 15 毫秒
51.
The aims of the present study were (i) to assess the in vitro genetic stability of S19 and RB51 Brucella abortus vaccines strains and (ii) to evaluate the ability of multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) as a tool to be used in the quality control of live vaccines against brucellosis. Sixty-three batches of commercial S19 (n = 53) and RB51 (n = 10) vaccines, produced between 2006 and 2009, were used in this study. S19 and RB51 vaccines were obtained from, respectively, seven and two different manufacturers. Ten in vitro serial passages were performed on reference strains and on selected batches of commercial vaccines. All batches, reference strains and strains of serial passages were typed by the MLVA16. The results demonstrated that B. abortus S19 and RB51 vaccine strains are genetically stable and very homogeneous in their respective groups. Anyway, batches of S19 from one manufacturer and batches of RB51 from another presented genotypes distincts from the reference vaccine strains. In both cases, differences were found on locus Bruce07, which had addition of one repeat unit in the case of S19 batches and the deletion of one repeat unit in the case of RB51 batches. In summary, MLVA16 proved to be a molecular tool capable of discriminating small genomic variations and should be included in in vitro official tests.  相似文献   
52.
Various factors have been described as phenotypic modulators of sickle cell disease, such as levels of fetal hemoglobin (Hb F), presence of α-thalassemia (thal), and haplotypes of the β-globin genes. In order to characterize and determine the frequency of the βS and βC mutations and the prevalence of ?α3.7-thal, 74 patients with sickle cell disease detected during neonatal screening in the State of Pernambuco, Brazil, were studied. The haplotypes of the β gene and ?α3.7-thal were determined using polymerase chain reaction (PCR), and specific restriction endonucleases were used to establish the polymorphic sites of the haplotypes. The results showed the high frequency of the Central African Republic (CAR) or Bantu haplotype in the State of Pernambuco, Brazil. The low frequency of the Benin haplotype recorded in this study, in comparison with other states in northeast Brazil, suggests the diversity of origins of Afro-Brazilians in this region.  相似文献   
53.
54.
Twenty-eight adults with chronic myelogenous leukemia (CML) that had relapsed after allogeneic stem cell transplantation (SCT) received imatinib mesylate (400-1000 mg/d). Disease was in chronic phase in 5 patients, accelerated in 15, and blastic in 8 (7 medullary, 1 extramedullary); median time from transplantation to relapse was 9 months (range, 1-137 months). Thirteen patients had undergone salvage donor lymphocyte infusion (DLI) (median time from DLI to imatinib mesylate therapy, 4 months [range, 2-39 months]). The overall response rate was 79% (22 of 28 patients); the complete hematologic response (CHR) rate was 74% (17 of 23 patients), and the cytogenetic response rate was 58% (15 of 26 patients; complete response in 9 [35%] patients). CHR rates were 100% for chronic phase, 83% for accelerated phase, and 43% for blastic phase. The patient with extramedullary blastic disease achieved complete response. Cytogenetic response rates were 63% (12 of 19 patients) for chronic or accelerated phases (complete cytogenetic response in 8) and 43% for blastic phase (3 of 7 patients). At median follow-up of 15 months, 19 patients were alive, 9 with no evidence of disease. The 1-year estimated survival rate was 74%. Five patients had recurrence of grade 3 (3 patients) or grades 1 to 2 (2 patients) graft-versus-host disease (GVHD). Severe granulocytopenia developed in 43% of patients and thrombocytopenia in 27%; both conditions reversed with dose adjustments of imatinib mesylate. We conclude that imatinib mesylate effectively controlled CML that recurred after allogeneic SCT, but it was associated with side effects including myelosuppression and recurrence of severe GVHD.  相似文献   
55.
We studied the value of an IgG Western blot (WB) with Paragonimus kellicotti (Pk) antigen for diagnosis of North American paragonimiasis. The test was evaluated with sera from patients with Pk and Paragonimus westermani infections, with control sera from patients with other helminth infections, and sera from healthy Americans. All 11 proven Pk infection sera and two samples from suspected cases that were negative by P. westermani WB at the Centers for Disease Control and Prevention (CDC) contained antibodies to antigens at 34 kDa and at 21/23 kDa. Seven of 7 P. westermani sera contained antibodies to the 34 kDa antigen, but only 2 recognized the 21/23 kDa doublet. No control samples were reactive with these antigens. Antibody reactivity declined after praziquantel treatment. Thus, the P. kellicotti WB appears to be superior to P. westermani WB for diagnosing Pk infections, and it may be useful for assessing responses to treatment.  相似文献   
56.
57.
58.
59.
Context  Congenital generalized lipodystrophy, or Berardinelli–Seip syndrome, is a rare autosomal recessive disease caused by mutations in either the BSCL2 or AGPAT2 genes. This syndrome is characterized by an almost complete loss of adipose tissue usually diagnosed at birth or early infancy resulting in apparent muscle hypertrophy. Common clinical features are acanthosis nigricans, hepatomegaly with or without splenomegaly and high stature. Acromegaloid features, cardiomyopathy and mental retardation can also be present.
Design  We investigated 11 kindreds from different geographical areas of Brazil (northeast and southeast). All coding regions as well as flanking intronic regions of both genes were examined. Polymerase chain reaction (PCR) amplifications were performed using primers described previously and PCR products were sequenced directly.
Results  Four AGPAT2 and two BSCL2 families harboured the same set of mutations. BSCL2 gene mutations were found in the homozygous form in four kindreds (c.412C>T c.464T>C, c.518–519insA, IVS5-2A>G), and in two kindreds compound mutations were found (c.1363C>T, c.424A>G). In the other four families, one mutation of the AGPAT2 gene was found (IVS3-1G>C and c.299G>A).
Conclusions  We have demonstrated four novel mutations of the BSCL2 and AGPAT2 genes responsible for Berardinelli–Seip syndrome and Brunzell syndrome (AGPAT2-related syndrome).  相似文献   
60.
The introduction of multidrug therapy by the World Health Organization has dramatically reduced the world prevalence of leprosy but the disease is still a public health problem in many countries, with a world prevalence of almost 600,000 cases in 2001. Damage to peripheral nerves is a key component of leprosy and the sensory and motor loss that follows is the basis for many of the classical features of this disease, such as skin wounds, cracks, plantar ulcers, clawed hands, drop foot, and incomplete closure of the eyelids. One of the most remarkable aspects of leprosy to lay persons and health care workers alike is that patients are reputed to feel no pain. However, neuropathic pain is arising as a major problem among leprosy patients. It can be nociceptive due to tissue inflammation, which mostly occurs during episodes of immune activation or neuropathic due to damage or dysfunction of the nervous system. This study, conducted among 358 leprosy patients, reveals a considerable prevalence of neuropathic pain and presents evidence that this common problem should be a high priority of those in charge of leprosy control programs.  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