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   450篇
  免费   19篇
  国内免费   3篇
耳鼻咽喉   9篇
儿科学   15篇
妇产科学   19篇
基础医学   50篇
口腔科学   15篇
临床医学   68篇
内科学   83篇
皮肤病学   6篇
神经病学   58篇
特种医学   19篇
外科学   65篇
预防医学   30篇
眼科学   9篇
药学   16篇
肿瘤学   10篇
  2023年   8篇
  2022年   6篇
  2021年   7篇
  2020年   4篇
  2019年   5篇
  2018年   13篇
  2017年   10篇
  2016年   5篇
  2015年   5篇
  2014年   5篇
  2013年   16篇
  2012年   24篇
  2011年   24篇
  2010年   14篇
  2009年   13篇
  2008年   36篇
  2007年   40篇
  2006年   28篇
  2005年   18篇
  2004年   21篇
  2003年   16篇
  2002年   19篇
  2001年   17篇
  2000年   17篇
  1999年   11篇
  1998年   6篇
  1997年   3篇
  1996年   3篇
  1995年   6篇
  1993年   3篇
  1992年   9篇
  1991年   2篇
  1990年   4篇
  1989年   2篇
  1988年   5篇
  1987年   6篇
  1986年   4篇
  1985年   5篇
  1984年   4篇
  1983年   5篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1979年   2篇
  1978年   2篇
  1973年   1篇
  1972年   5篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
排序方式: 共有472条查询结果,搜索用时 15 毫秒
1.
2.
Beta-thalassemia major (TM) is caused by any of approximately 150 mutations within the beta-globin gene. To establish the degree of chimerism after bone marrow transplantation (BMT), we have performed molecular analysis of beta-globin mutations in 14 patients with TM over a period of 10 years. All patients underwent T cell-depleted allogeneic BMT from HLA-identical related donors, using either in vitro T-cell depletion with CAMPATH 1M and complement or in vivo depletion using CAMPATH 1G in the bone marrow collection bag. To date, at different time periods after BMT, seven patients have some degree of chimerism; six of these patients, all blood transfusion-independent, have donor cells in the range of 70% to 95%, with stable mixed chimerism (MC). The seventh patient has less than 10% donor cells with, surprisingly, only minimal transfusion requirements. The detection of beta-globin gene point mutation, as used here, is a highly specific and sensitive marker for engraftment and MC in patients with thalassemia. In light of its specificity, the method is applicable in all cases of TM, as it is independent of sex and other non-globin-related DNA markers. The high incidence of MC found in our patients may be a consequence of the pre- BMT T-cell depletion. Because MC was associated with transfusion independence, complete eradication of residual host cells for effective treatment of TM and possibly other genetic diseases may prove not to be essential.  相似文献   
3.
A rare case of thymic carcinoma with multiple brain metastasis is reported. In our extensive review of the literature only six of 30 reports of intracranial thymoma metastasis describe multiple metastases. A 38-year-old man presented with signs of raised intracranial pressure that had began 15 days previously. Cranial MRI revealed over 70 cystic lesions in the supra and infratentorial regions. Stereotactic biopsy was planned. On the second day of his admission he deteriorated and died the following day. The autopsy revealed a mass in the mediastinum. In the brain parenchyma were multiple cystic lesions between 0.5 and 3 cm in diameter. Histopathologically they were diagnosed as metastases from the thymic carcinoma. The mean survival with a single brain metastasis is approximately 256 days, whereas with multiple brain metastases it is only 64 days, thus treatment of this tumor demands prompt surgery whenever possible and optimal adjuvant therapy.  相似文献   
4.
OBJECTIVE: The objective of this study was to determine the prevalence of sexual dysfunction in patients with schizophrenia under antipsychotic therapy and to investigate the effect of various parameters on sexual dysfunction. METHOD: A total of 827 stabilized outpatients who met DSM-IV criteria for schizophrenia, were recruited in the study. Arizona Sexual Experience Scale (ASEX) and the subscale on sexual function of the UKU Side Effects Rating Scale were applied at a single interview. RESULTS: In total, 52.6% of the patients had sexual dysfunction, 54.2% reported a low sexual desire and 41.7% reported problems in having an orgasm. Erectile dysfunction and ejaculation problems were seen in 48.1% and 64.2% of the men, respectively; amenorrhea was seen in 24.9% of the women. ASEX score and severity of disease were found to be correlated (p=0.02). Higher ASEX scores were observed in patients who smoked (p=0.01). Men receiving atypical monotherapy had lower ASEX scores than those receiving a combination of atypical and conventional antipsychotics (p=0.017). Patients on combination therapy had more ejaculation problems than the atypical group (p=0.001). Low sexual desire was more prevalent among women using conventional drugs than those on atypical drugs (p=0.004). In linear regression analyses, ASEX was affected significantly and independently by the severity of the disease only in men (p=0.005). CONCLUSION: Our results show that sexual dysfunction is widespread among patients with schizophrenia on antipsychotic medications.  相似文献   
5.
This study was conducted to determine the source and number of primary sensory neurons (PSNs) innervating a mandibular molar tooth of a population of 15-18-week-old Sprague-Dawley rats. The pulpal tissue was exposed to horseradish peroxidase (HRP) pellets for 24 hours. Subsequently the animals were perfusion fixed and the following PSN structures were examined for the presence of HRP-labelled cells: trigeminal (TGs) and cervical dorsal root ganglia (DRGs) and mesencephalic nucleus (MN). Only the TGs contained labelled cells and they thus were the sole source of PSN pulpal innervation. The number of TG cells was highly variable, 49-407, but most of this variability was attributable to insufficient HRP filling of the pulp chamber or leakage of HRP into periapical tissue. Selection of TGs whose respective experimental teeth demonstrated that HRP filled and was restricted to the pulp chamber revealed a narrower range of TG cells providing pulpal innervation to the first molars, 142-288, with an average of 213. A detailed mapping of these cells indicated a somatotopic distribution within the mandibular territory of the TGs. It was concluded that these findings represent TG's contribution to the pulpal innervation of this specific population of rat first molar teeth. This suggests that from animal to animal the density of innervation may be quite variable and it is hypothesized that the sensitivity of the pulp would likewise vary. In addition, these findings may contribute to the explanation of why there is variability in the stimulus strength needed to elicit a pain response in the human dentition.  相似文献   
6.
The Health Council of the Netherlands published a report in which the best procedure and method for recommending health‐based occupational exposure limits (OELs) for inhaled allergens were identified by evaluating the scientific state of the art. Many respiratory disorders in the workplace arise from inhalation of substances which can cause allergy. To protect workers against respiratory allergy, various preventive measures are taken, one of them being reduction of exposure by setting legally binding standards. These are based on health‐based OELs that specify a level of exposure to an airborne substance, a threshold level, below which it may reasonably be expected that there is no risk of adverse health effects. The Council is of the opinion that an OEL should prevent against allergic sensitization, as sensitization plays a crucial biological role and is a prerequisite for the development of allergy. Furthermore, the Council considers it most likely that the exposure level below which no allergic sensitization develops for most allergens is so low, that OELs are difficult to set with the current knowledge and technical feasibilities. An alternative approach is to accept exposure, which carries a small predefined risk in developing allergic sensitization. In addition, it is worth considering periodic screening of exposed workers on allergic sensitization, because timely intervention can prevent worse. The feasibility of periodic screening and what else is needed to comply with the most important criteria, should however be judged case‐by‐case.  相似文献   
7.
In order to determine the positivity rate and genotype of Epstein-Barr virus (EBV) in cases with Hodgkin's disease (HD) in Turkey, 40 tissue specimens from HD patients were analysed. Ten non-lymphoid tissue samples from individuals without any evidence for lymphoma were used as controls. The cases with HD included 33 males and 7 females with a mean age of 28 years. Nodular sclerosis was the most prevalent histological subtype (16/40) followed by mixed cellularity (10/40), lymphocyte predominance (9/40), and lymphocyte depletion (5/40). After histopathological evaluation, deparafinisation and lysis of the specimens, one-stage polymerase chain reaction (PCR) and two-stage (nested) PCR assays were performed with the primers common for both EBV genotypes and the primers specific for EBV types 1 and 2, respectively. EBV DNA was detected in 22 of 40 (55%) cases with HD and in 1 of 10 (10%) control specimens. The distribution of EBV DNA positivity according to the histological subtypes was as follows: 10 of 16 (62.5%) for nodular sclerosis, 3 of 5 (60%) for lymphocyte depletion, 5 of 9 (55.6%) for lymphocyte predominance, and 4 of 10 (40%) for mixed cellularity. Although most of the HD patients were males of 15-34 years of age, there were no significant differences between EBV positivities obtained from different sex and age groups. The rates of EBV genotypes were 82% for type 1, 9% for type 2, and 9% for both types, respectively.  相似文献   
8.
CONTEXT: Apoptosis occurs in the normal placenta. The monoclonal antibody M30 is directed against a novel epitope of cytokeratin 18 (CK18) that is formed by caspase cleavage early in the apoptotic cascade, and this antibody may therefore be useful for evaluating trophoblast apoptosis. OBJECTIVE: We undertook the present study to evaluate the use of monoclonal antibody M30 to assess trophoblast apoptosis in placenta at term. METHODS: We stained paraffin-embedded placental tissues from 15 deliveries at term with M30. We compared positive M30 staining and CK18 staining (as detected by a monoclonal antibody directed against CK18) of trophoblasts in serial slides. We also compared apoptotic rates as detected by M30 and TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling) in 7 of the placentas. RESULTS: In fields of villous tissue, most M30-positive cells were CK18-positive syncytiotrophoblasts. Approximately half of M30-positive cells occurred as focal positive staining in the syncytial layer, and half occurred as abundant staining of syncytiotrophoblasts in areas with increased intervillous or perivillous fibrinoid. We found very few M30-positive cells in villous stroma. In decidual/basal plate tissues, most (two thirds) of the M30-positive cells were CK18-positive extravillous trophoblasts, whereas one third were syncytiotrophoblasts of anchoring villi. Since TUNEL detects apoptosis in both epithelial and nonepithelial cells, more cells were positively stained with TUNEL than with M30 in some tissue fields. However, our observations suggest that M30 was more sensitive than TUNEL in recognizing apoptotic trophoblasts and had less nonspecific staining than TUNEL. CONCLUSION: We recommend the use of monoclonal antibody M30 for apoptosis studies in placental tissues. This antibody is easy to handle, the staining obtained seems specific, and the nonspecific staining seems negligible.  相似文献   
9.
10.
We present a rare case of a placental teratoma found within the fetal membranes of an otherwise normal placenta. Lack of a recognizable umbilical cord and no recognizable skeletal development are used as differential diagnostic criteria for a placental teratoma. In our case, an umbilical cord was absent; nevertheless, the tumor contained two vascular channels covered only by fetal membranes without Wharton's jelly.  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