Dear Sir, We read with interest ‘Chlamydia trachomatis in infertilewomen undergoing uterine instrumentation: Screen or treat’(Land et al., 2002), proposing that prophylactic antibioticsshould be given to all infertile women undergoing uterine instrumentationinstead of screening for C. trachomatis and treating positivecases only. Universal screening was not considered by the authorsto be cost-effective in view of the low incidence of detectionof C. trachomatis in the endocervix  相似文献   
74.
New alleles in the B44 family including B*44022, B*44032, B*4411, B*4420, B*4421, B*4424, and B*8301     
Steiner NK  Gans CP  Kosman C  Bradshaw D  Koester R  Menchaca EM  Mitton W  Ng J  Hartzman RJ  Hurley CK 《Tissue antigens》2001,57(4):376-379
Seven new HLA-B locus alleles have been described. B*44022 and B*44032 are silent substitutions altering known alleles. B*4411 carries a unique Bw4-like epitope. B*4420, B*4421, and B*4424 carry new combinations of motifs previously observed in other alleles. B*8301 appears to be the result of the replacement of exon 2 from B*4402 with exon 2 from B*5603.  相似文献   
75.
Systemic autoimmune disease induced by dendritic cells that have captured necrotic but not apoptotic cells in susceptible mouse strains   总被引:1,自引:0,他引:1  
Ma L  Chan KW  Trendell-Smith NJ  Wu A  Tian L  Lam AC  Chan AK  Lo CK  Chik S  Ko KH  To CK  Kam SK  Li XS  Yang CH  Leung SY  Ng MH  Stott DI  MacPherson GG  Huang FP 《European journal of immunology》2005,35(11):3364-3375
Systemic lupus erythematosus (SLE) is an autoimmune disorder of a largely unknown etiology. Anti-double-stranded (ds) DNA antibodies are a classic hallmark of the disease, although the mechanism underlying their induction remains unclear. We demonstrate here that, in both lupus-prone and normal mouse strains, strong anti-dsDNA antibody responses can be induced by dendritic cells (DC) that have ingested syngeneic necrotic (DC/nec), but not apoptotic (DC/apo), cells. Clinical manifestations of lupus were evident, however, only in susceptible mouse strains, which correlate with the ability of DC/nec to release IFN-gamma and to induce the pathogenic IgG2a anti-dsDNA antibodies. Injection of DC/nec not only accelerated disease progression in the MRL/MpJ-lpr/lpr lupus-prone mice but also induced a lupus-like disease in the MRL/MpJ-+/+ wild-type control strain. Immune complex deposition was readily detectable in the kidneys, and the mice developed proteinuria. Strikingly, female MRL/MpJ-+/+ mice that had received DC/nec, but not DC/apo, developed a 'butterfly' facial lesion resembling a cardinal feature of human SLE. Our study therefore demonstrates that DC/nec inducing a Th1 type of responses, which are otherwise tightly regulated in a normal immune system, may play a pivotal role in SLE pathogenesis.  相似文献   
76.
Evaluation of a Selective Transport Medium for Gastric Biopsy Specimens To Be Cultured for Helicobacter pylori   总被引:1,自引:0,他引:1       下载免费PDF全文
L. K. Siu  W. K. Leung  A. F. B. Cheng  J. Y. Sung  T. K. W. Ling  J. M. L. Ling  E. K. W. Ng  J. Y. W. Lau    S. C. S. Chung 《Journal of clinical microbiology》1998,36(10):3048-3050
Since the means of culturing Helicobacter pylori may not be available in some laboratories, prolonging the survival of this organism during transportation is a major concern in terms of improving detection rates. A selective transport medium was evaluated for the preservation of H. pylori from 254 gastric biopsy specimens collected from a rural area in China where culturing is not feasible. Gastric biopsy specimens were inoculated in sterile broth consisting of brain heart infusion (BHI) broth, horse serum, and yeast extract supplemented with vancomycin, amphotericin B, and nalidixic acid (VAN). Of the 254 biopsy specimens, 238 were identified by histology to have H. pylori infection. Total rates of recovery of H. pylori from the H. pylori-positive gastric biopsy specimens stored in the BHI-VAN broth ranged from 76 to 46% after storage of specimens for 5 to 9 days. In conclusion, the selective medium is useful for prolonging the survival of H. pylori in gastric biopsy specimens for which immediate culture is not feasible.  相似文献   
77.
An immunohistochemical study of neuronal and glial cell reactions in retinae of rats with experimental glaucoma   总被引:5,自引:0,他引:5  
Wang X  Tay SS  Ng YK 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2000,132(4):476-484
Glaucoma is a common disease seen in the eye clinic, but its associated pathological processes, especially the role of glial cells in glaucomatous retinae, are still under debate. The aim of the present work was to study the responses of astrocytes, Müller cells and microglia in retinae of rats with experimental glaucoma. Glaucoma was induced in adult male Wistar rats by cauterizing limbal-derived veins and the changes in glial fibrillary acidic protein (GFAP), OX42, OX18, OX6 and EDI expression were studied by immunohistochemical staining. Neuronal cell viability was studied by immunostaining with the neuronal nuclei (NeuN) antibody. In the experimental glaucomatous eyes, a significant drop in the number of NeuN-positive neurons was observed from 7 days postoperation and beyond in both the ganglion cell layer and inner nuclear layer. The expression of GFAP and OX42 was increased during the first 2 months after operation and reduced in rats at 3 and 4 months. OX6 and OX18 immunoreactivity was induced in some microglia of both glaucomatous and sham-operated control eyes. Possible mechanisms of the reaction of astrocytes, Müller cells and microglia in neuronal degeneration following glaucoma are discussed.  相似文献   
78.
Ontogeny of the transition from killer to caregiver in dwarf hamsters (Phodopus campbelli) with biparental care     
Vella ET  Evans CC  Ng MW  Wynne-Edwards KE 《Developmental psychobiology》2005,46(2):75-85
Biparental Phodopus campbelli and uniparental P. sungorus juvenile litters (2 males, 2 females) both consumed amniotic fluid and placenta during the birth of younger siblings. Three days later, P. campbelli juveniles were most responsive to a displaced younger sibling. Thus, P. campbelli are responsive to pups as juvenile alloparents and as new parents; however, at intervening ages, infanticidal attack (bite) was seen. At 5, 7, 9, 11, or 13 weeks of age, male and female P. campbelli were given a 5-min test with an unrelated, 3-day-old, anesthetized pup. Females attacked more often than males, yet pup-retrieval rates did not differ. Female aggression increased with age and was replaced by retrieval behavior 3 days after parturition. Male attack ceased after a birth, but parental behavior did not increase, remaining below the rate for new fathers tested with their own awake pup. Over repeated testing, behavior in one test did not predict behavior in another. Transitions from caregiving alloparent to infanticidal adult and back to parental care were clear in females, but less discrete with this stimulus paradigm in these highly paternal males.  相似文献   
79.
Eighty consecutive cases of gamete intra-Fallopian transfer     
Wong  P.C.; Ng  S.C.; Hamilton  M.P.R.; Anandakumar  C.; Wong  Y.C.; Ratnam  S.S. 《Human reproduction (Oxford, England)》1988,3(2):231-233
Eighty patients with the main problems of unexplained infertility,oligospermia and endometriosis were treated with gamete intraFallopiantransfer (GUT). From 80 treatment cycles, 29 women conceived(36.3%). Of these, four were biochemical pregnancies and thereforethe clinical pregnancy rate (25/80) was 31.2%. There were sixsets of multiple pregnancies, a multiple pregnancy rate of 24%.Three women (12%) miscarried. The pregnancy rates in the patientswith unexplained infertility, oligospermia and endometriosiswere 33.3, 16.7 and 38.5%, respectively. The transfer of fouroocytes appears to increase the pregnancy rate without increasingthe risk of multiple pregnancy. The presence of in-vitro fertilizationof excess oocytes after GIFT did not correlate with the finaloutcome of GIFT  相似文献   
80.
Reactive hemophagocytic syndrome: a study of 7 fatal cases     
J K Chan  C S Ng  C K Law  W F Ng  K F Wong 《Pathology》1987,19(1):43-50
Reactive hemophagocytic syndrome is a clinico-pathologic entity characterized by systemic proliferation of non-neoplastic histiocytes showing phagocytosis of hemopoietic cells, resulting in blood cytopenia. It is best known to be associated with virus infection, but other associated diseases have also been implicated. The clinical and pathological findings of 7 fatal cases are described. The syndrome affected both sexes of a wide age range, and all patients had fever. Significant laboratory findings were blood cytopenia, abrupt drop in the blood cell counts, deranged liver function tests and abnormal coagulation profile. The associated diseases were diverse: two patients had bacterial infection; two had peripheral T-cell lymphoma; one had disseminated undifferentiated carcinoma of the ovary; one had both tuberculosis and disseminated nasopharyngeal carcinoma, and one had no obvious underlying disease. It is postulated that lymphokines secreted by lymphoid cells or tumor cells may be responsible for the systemic activation of histiocytes. The differential diagnosis from malignant histiocytosis is discussed.  相似文献   
[首页] « 上一页 [3] [4] [5] [6] [7] 8 [9] [10] [11] [12] [13] 下一页 » 末  页»
  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   13437篇
  免费   986篇
  国内免费   130篇
耳鼻咽喉   94篇
儿科学   474篇
妇产科学   407篇
基础医学   1794篇
口腔科学   281篇
临床医学   1171篇
内科学   2608篇
皮肤病学   216篇
神经病学   928篇
特种医学   530篇
外科学   2293篇
综合类   623篇
一般理论   4篇
预防医学   730篇
眼科学   342篇
药学   776篇
  1篇
中国医学   78篇
肿瘤学   1203篇
  2023年   126篇
  2022年   156篇
  2021年   340篇
  2020年   238篇
  2019年   311篇
  2018年   340篇
  2017年   272篇
  2016年   291篇
  2015年   354篇
  2014年   450篇
  2013年   555篇
  2012年   870篇
  2011年   919篇
  2010年   568篇
  2009年   487篇
  2008年   725篇
  2007年   690篇
  2006年   721篇
  2005年   709篇
  2004年   675篇
  2003年   605篇
  2002年   554篇
  2001年   522篇
  2000年   418篇
  1999年   362篇
  1998年   141篇
  1997年   130篇
  1996年   112篇
  1995年   101篇
  1994年   81篇
  1993年   66篇
  1992年   167篇
  1991年   151篇
  1990年   167篇
  1989年   166篇
  1988年   137篇
  1987年   146篇
  1986年   116篇
  1985年   91篇
  1984年   57篇
  1983年   48篇
  1982年   22篇
  1981年   38篇
  1980年   30篇
  1979年   55篇
  1978年   37篇
  1977年   35篇
  1976年   28篇
  1975年   26篇
  1973年   26篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
PURPOSE: Identification of the onset of muscle contraction with EMG signal amplitude double of the baseline value (DP-P) has been recently reported for determining the temporal parameters of muscular activity. Due to its convenience, it is suitable for clinical application. However, there is a lack of report on the reliability and comparability of this method to other established methods. Therefore, this study examined the test-retest reliability of the DP-P method and compared it with an established method that used the mean + 3 standard deviations (mean + 3 s.d.) over the baseline value for muscles of the knee. METHODS: The onset of contraction of vastus medialis obliquus (VMO) and vastus lateralis (VL) of eleven able-bodied volunteers performing isometric knee extension at 50%, 75% and 100% of MVC in 30-minute and 7-day intervals were analyzed with both the DP-P and mean + 3 s.d. methods. RESULTS: The ICC for within-day measurements of DP-P method ranged from 0.64 to 0.86 and that for between-day measurements ranged from 0.63-0.81. The ICC values were higher with submaximal than maximal contractions. There was a consistent delay of about 3 ms in EMG onset detection with the DP-P as compared to the mean + 3 s.d method. CONCLUSION: The DP-P method is a reliable method for muscle onset determination but the absolute onset time of muscle contraction obtained from this method should not be directly compared with other methods such as the mean + 3 s.d.  相似文献   
72.
Ng JC  Josefsson C  Clark AJ  Franz AW  Perry KL 《Virology》2005,332(1):397-405
The physical stability of virions of Cucumber mosaic virus (CMV) mutants was investigated to determine if relative stability correlated with efficiency of aphid transmission. Virion stability was evaluated by a urea disruption assay and by testing the infectivity of virus following purifications. All viruses were infectious when purified using a low salt buffer without organic solvent, whereas two of seven viruses were less stable and inactivated following purification with a high salt buffer and chloroform. These two viruses were both reassortants derived from the spontaneous transmission-defective mutant CMV-M (F1F2M3 and F1F2M3-L129P). F1F2M3 was relatively unstable, being disrupted between 0 and 1 M urea versus the wild-type CMV-Fny (F1F2M3) that was destabilized at 3-4 M urea. Modifications of F1F2M3 at three amino acid positions (129, 162, 168), singly or in combination, increased the relative stability of virions. A second class of transmission-defective CMVs with engineered mutations in the betaH-betaI surface loop of the CMV-Fny capsid protein (CP) exhibited near wild-type levels of stability. Lastly, a single Pro to Leu substitution at CP position 129 of CMV-Fny (F1F2M3-P129L) conferred the induction of necrosis in tobacco plants and reduced aphid transmissibility, but did not markedly alter the physical stability of virions. Thus, only among CMV-M derivatives harboring the CP mutation of Thr to Ala at position 162 were increases in stability correlated with restoration of transmissibility by the aphid Aphis gossypii.  相似文献   
73.
   Introduction
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