首页 | 官方网站   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   10188篇
  免费   484篇
  国内免费   63篇
医药卫生   10735篇
  2023年   48篇
  2022年   82篇
  2021年   183篇
  2020年   100篇
  2019年   169篇
  2018年   210篇
  2017年   174篇
  2016年   189篇
  2015年   198篇
  2014年   245篇
  2013年   290篇
  2012年   506篇
  2011年   540篇
  2010年   287篇
  2009年   254篇
  2008年   413篇
  2007年   475篇
  2006年   408篇
  2005年   461篇
  2004年   456篇
  2003年   434篇
  2002年   464篇
  2001年   351篇
  2000年   386篇
  1999年   354篇
  1998年   134篇
  1997年   119篇
  1996年   104篇
  1995年   89篇
  1994年   68篇
  1993年   60篇
  1992年   238篇
  1991年   227篇
  1990年   202篇
  1989年   191篇
  1988年   159篇
  1987年   182篇
  1986年   155篇
  1985年   146篇
  1984年   104篇
  1983年   85篇
  1979年   86篇
  1978年   61篇
  1977年   55篇
  1971年   57篇
  1970年   40篇
  1969年   44篇
  1968年   53篇
  1967年   43篇
  1966年   44篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Interest in quality assurance(QA) in clinical laboratories in Japan has increased over the past 30 years. We have however been lagging behind countries such as the USA, Canada and the UK in QA of clinical microbiology. The main problem of QA in Japan is human resources. There are only about 400 laboratory physicians certified by the Japanese Society of Laboratory Medicine(JSLM). Almost no academics in microbiology are interested in QA and they mostly lack clinical competence. There is a small number of faculty positions, and promotions are mostly based on research productivity while medical graduates are increasingly drawn to bench work for basic, short-term research. The Japanese Society for Clinical Microbiology (JSCM) was established in 1990 in order to promote the development of clinical microbiology and its relevant fields in Japan. And 2001 was a milestone in sustained efforts of the JSLM to initiate qualifying examinations of medical technologists(MT) in clinical microbiology. 105 MT in clinical microbiology were newly certified by the Joint Committee of JSCM, JSLM, Japanese Association of Medical Technologists (JAMT) and College of Clinical Pathology of Japan(CCPJ). The certified MTs have appropriate educational background and are well motivated. With good on-the-job training, they are expected to perform effectively various tasks, including laboratory management. Recent radical changes in the health care delivery system have also had serious implications on laboratory services and QA of microbiological tests. The primary goal of the clinical microbiology laboratory is to provide accurate diagnostic testing and high-quality service at a low cost for its customers. It is believed that the Joint Committee and the newly certified MTs will contribute to narrowing the gap between Japan and other countries in clinical microbiology.  相似文献   
52.
Dysfunction of the dopaminergic system has been suggested as a pathogenic mechanism in neuroleptic malignant syndrome. Therefore, we examined the complete coding sequences of the dopamine D2 receptor (DRD2) gene for structural abnormalities in 12 patients with a history of NMS, including two cases of familial NMS. Mutational analysis was performed by denaturing gradient gel electrophoresis (DGGE), a highly sensitive technique for detecting sequence differences. We found in one patient with a history of NMS a nucleotide substitution at codon 310 (CCG→TCG) of exon 7 of the DRD2 gene which predicts the replacement of proline to serine in the third cytoplasmic loop of the receptor, a part of the receptor that interacts with G-proteins. A larger series of patients with NMS needs to be investigated to establish whether this allele is associated with an increased susceptibility to NMS. © 1995 Wiley-Liss, Inc.  相似文献   
53.
54.
BACKGROUND: Tachykinins are involved in the development of bronchial inflammation and airway hyperresponsiveness (AHR); however, the role of the neurokinin-1 (NK(1)) receptor in acid-aerosol-induced bronchial impairment in asthmatic patients remains controversial. METHODS: To investigate the effects on the NK(1) receptor antagonist FK888 the neurokinin-2 (NK(2)) receptor antagonist SR48968 on sulfuric-acid (H(2)SO(4))-induced AHR in guinea pigs, specific airways resistance (sRaw) and airways responsiveness to methacholine (MCh) were measured before and after 6 h of exposure to H(2)SO(4) aerosol (pH 1.7, 82 mg/m(3)) in ovalbumin-sensitized guinea pigs. RESULTS: Airway responsiveness to MCh significantly increased (p<0. 05) after the exposure, however sRaw did not. Treatment with FK888 significantly inhibited (p<0.05) H(2)SO(4)-induced AHR in a dose-dependent manner, as did SR48968. CONCLUSIONS: These results suggest that not only NK(2) but also NK(1) receptors might have important roles in the development of acid-aerosol-induced AHR.  相似文献   
55.
To clarify the correlation of genomic alterations with clinical and histological features, we performed metaphase comparative genomic hybridization analysis on 20 primary cutaneous melanomas, which were obtained by laser capture or manual microdissection, and 16 melanoma cell lines. There were no differences in the average number of aberrations between acral melanomas (AM) and non-AM, although gains of 5q and 11q13 were more frequent (P=0.05) and 10q loss was less frequent (P=0.01) in AM than in non-AM. Although tumor thickness is considered a measurable estimate of clinical expression, there were no differences in the average number of aberrations among 4 groups, classified by thickness of the tumor. While the majority of aberrations were equally distributed among the 4 groups, 6p gains were found only in the thickest tumors. Patients with 6p or 1q gains had a lower overall survival rate than those without them (P=0.0002 or P=0.013). While gains of 1q, 2q, 3p, 3q, 7q, 20p, and 20q were more frequent in the cell lines than in the primary tumors (P<0.01), losses of 6q, 9p, 10p, and 10q were equally found in both cell lines and primary tumors. The present study showed that chromosomal aberrations had already occurred in the thinner tumors, and that 6p and 1q gains may be a prognostic factor.  相似文献   
56.
Ossifying fibromyxoid tumor (OFMT) of soft parts is a recently described, rare but morphologically distinctive soft tissue tumor. The histogenesis of this lesion remains uncertain, although several immunohistochemical and ultrastructural features suggest that it is an unusual neural tumor, possibly of Schwann cell origin. We report here a case of a malignant variant of OFMT that occurred in the foot of a 52-year-old man. The karyotype of a pulmonary metastasis exhibited the following complex numeric and structural aberrations:72 approximately 74,XXY,-5,+6,+del(8)(p21),del(9)(p22),+10,der(11)t(3;11)(p21;p15),del(12) (q13),der(13)t(5;13)(q13;q34),+18,+19,+20,-22 [cp10]. A kidney metastasis exhibited the following karyotypic abnormalities: 46,XY,add(3)(p11),+der(3)t(3;?;11)(3qter-->3p11::?::11q13-->11qter), -5,del(8)(p21),add(9)(q22),del(9)(p22),der(11)t(3;11)(p21;p15),del(12)(q13),+der(13)t(5;13) (q13;q34),-22. To our knowledge, this is the first reported case of OFMT in which clonal chromosomal aberrations have been shown.  相似文献   
57.
58.
The cytogenetic and morphologic characteristics of a case with a primitive neuroectodermal tumor (PNET) arising from the left kidney in a 22 year old man are presented. The patient was detected as having a left renal mass with a tumor embolus In the inferior vena cava and multiple pulmonary metastases. A radical nephrectomy with tumor embolectomy of the Inferior vena cava, along with a resection of the pulmonary nodules were performed. Histologic examination revealed a dense proliferation of small round cells with many Homer-Wright type rosettes and perlvascular pseudo-rosettes. Immunohlstochemically, the tumor cells stained strongly positive for HBA71(p30/32M IC2), a surface glycopro-teln specific to PNET and Ewlng's sarcoma. In addition, the tumor cells expressed several neural markers (neuron specific enolase, neurofilament, synaptophysin, and Leu-7) and vimentin, while the epithelial, muscular, and lymphocytlc markers were negative in the tumor cells. Cytogenetic analysis of cultured tumor cells showed a reciprocal translocation t(11; 22)(q24; q12) that is considered to be specific to PNET and Ewing's sarcoma. In conclusion, this case suggested that a karyotyping analysis is a useful diagnostic tool for renal PNET, and it may therefore be utilized to help distinguish between difficult cases of small round cell tumors and Wilms' tumor of the kidney.  相似文献   
59.
60.
The authors examined 10 patients with Gerstmann-Sträussler syndrome or Creutzfeldt-Jakob disease and 10 with Alzheimer''s disease (AD). Immunohistochemistry using anti-prion protein (PrP) and anti-beta/A4 protein (beta/A4) coupled with formic acid pretreatment could detect Congophilic and non-Congophilic deposits. Prion protein deposits were classified into five types and compared with types of beta/A4 deposits. Kuru plaques with multicentric cores and fine granular deposits were a characteristic feature of PrP deposits. Some types of PrP or beta/A4 deposits depend on the anatomic sites. To clarify the relationship of microglia and astrocytes to PrP or beta/A4 deposits, double-immunostaining method was performed. In both kuru and senile plaques, microglia were closely linked to the Congophilic plaques. Astrocytes, however, extended their processes toward the plaques even in the non-Congophilic plaques. These observations strongly suggest that similar glial association with plaque formation may be involved in both kuru and senile plaques, although the amyloid core proteins differ.  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-23

京公网安备 11010802026262号