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   119篇
  免费   21篇
耳鼻咽喉   1篇
妇产科学   2篇
基础医学   17篇
临床医学   9篇
内科学   37篇
神经病学   1篇
特种医学   1篇
外科学   5篇
综合类   6篇
预防医学   29篇
眼科学   23篇
药学   6篇
肿瘤学   3篇
  2005年   5篇
  2004年   5篇
  2003年   4篇
  2002年   3篇
  2000年   4篇
  1999年   2篇
  1996年   2篇
  1995年   4篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1989年   2篇
  1988年   3篇
  1987年   2篇
  1986年   2篇
  1985年   6篇
  1983年   6篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1977年   5篇
  1974年   3篇
  1972年   2篇
  1965年   1篇
  1960年   1篇
  1959年   1篇
  1956年   1篇
  1954年   1篇
  1949年   1篇
  1948年   1篇
  1945年   1篇
  1944年   1篇
  1943年   2篇
  1940年   3篇
  1937年   1篇
  1936年   1篇
  1935年   1篇
  1934年   1篇
  1933年   1篇
  1932年   1篇
  1931年   1篇
  1930年   3篇
  1929年   2篇
  1928年   6篇
  1927年   4篇
  1925年   2篇
  1923年   4篇
  1922年   5篇
  1920年   1篇
排序方式: 共有140条查询结果,搜索用时 15 毫秒
1.
Human cartilage link protein exists as three native components, while equine, bovine, and porcine cartilage link protein exist as two and Swarm rat chondrosarcoma link protein exists as only one component. These nonhuman link protein components represent intact protein structures, and there is little evidence for proteolytically modified forms in nonhuman tissues. In human cartilage, the proteolytic production of modified link proteins increases with age, whereas high amounts of such products were not seen in the nonhuman tissues. However, the small amounts of link protein fragments that were observed in the nonhuman cartilages were of a similar size to their human counterparts. On digestion of human proteoglycan aggregate with stromelysin, rapid modification of the link protein components occurred, whereas the aggregates from nonhuman cartilages showed incomplete cleavage of their link protein components. The relative resistance of nonhuman link protein to stromelysin may in part be due to a unique amino acid substitution present near the enzymic cleave site.  相似文献   
2.
3.
The conventional structure of undergraduate medical education makes the implicit assumption that a "sound basis" in the understanding of the basic science disciplines is an essential prerequisite for starting clinical studies. It further assumes that the context within which the facts are presented is appropriate to this purpose and that demonstration of basic science knowledge is sufficient for the commencement of clinical studies. The precise structure of the preclinical phase of the medical course varies slightly from medical college to medical college but in general remains not unlike that described by Abraham Flexner more than 70 years ago, with the exception that it now packs many more facts and details into a similar space. The time has come to question the assumptions and to review the objectives of studying the basic medical sciences and the competencies that a student needs in order to progress to clinical studies. The author in this article reviews the available data and concludes that there is a substantial need for reform of the aims, content, and context of the learning in medical school preceding the clinical years.  相似文献   
4.
Increasing use of electronic data storage and exchange is inevitable. Although of considerable benefit to all concerned, they pose a potential threat to personal privacy. Measures to protect personal privacy in national information networks are essential. These and related security issues require the highest priority in strategic planning because experience shows that poor handling of security is the single factor most likely to lead to rejection of a system. It is increasingly important to be able to identify individuals uniquely for health-related purposes, and implementation of an on-line master index is the approach that has been adopted in New Zealand to address this need. Such an index, however, contains personal information, the privacy of which must be respected. Substituting the unique identifier for all personal details in electronic messages can provide a degree of security as long as access to the index is controlled and usage is monitored. The article outlines the measures, technical and otherwise, implemented to manage security concerns successfully in that context.  相似文献   
5.
Intraobserver and interobserver reproducibility of the FAB classification was assessed for two independent observers whose decisions are acted on for treatment of patients with acute leukemia in the Hamilton region. Intraobserver reproducibility was assessed for Wright-stained preparations that were examined independently on two consecutive occasions at least 2 weeks apart. A third reading was performed with Wright stain and cytochemical data, and the fourth reading was done with addition of immunophenotype data. Concordance was calculated using a statistic that corrects for chance-expected agreement (k), and a weighted statistic that takes into account the seriousness of disagreements was used. Samples were available for morphological and cytochemical assessment on 105 patients, and immunophenotype data were available on 93 specimens. Intraobserver concordance was 64.8% and 70.5% for observers A and B, respectively, with kappa values of .56 and .62. There were 37 discordant readings for observer A and 31 for observer B, with each observer discordant between lymphocytic:nonlymphocytic phenotypes in ten cases. Concordance between observers was 63% (k = .54) and 72% (k = .65) for each of two separate readings for Wright-stained preparations only. Reproducibility improved to 89% (k = .86) when cytochemistry was added. When immunophenotype information was provided in addition to Wright-stained and cytochemical preparations, the agreement was 99%. Lymphocytic:nonlymphocytic discordance between observers occurred on nine occasions when Wright-stained preparations only were available and four times when cytochemistry was added; it did not occur with immunophenotyping. The study suggests that immunophenotyping, when added to morphological assessment of acute leukemia, may contribute substantially to agreement between observers.  相似文献   
6.

OBJECTIVES:

To describe the immunogenicity and safety of a two-dose series of a quadrivalent meningococcal (serogroups A, C, Y and W) polysaccharide diphtheria toxoid conjugate vaccine (MenACYW-D) administered to toddlers.

METHODS:

Children were randomly assigned (1:1) at study entry to receive MenACYW-D at 12 and 18 months of age (group 1; n=61) or meningococcal serogroup C conjugate vaccine (MCC) at 12 months of age (group 2; n=62). All received routine childhood immunizations. A, C, Y and W antibody titres were measured in group 1 before and one month after the 18-month MenACYW-D vaccination and were measured in group 2 at one and seven months post-MCC vaccination. Antibodies elicited by diphtheria and tetanus toxoids, and acellular pertussis vaccine adsorbed combined with inactivated poliomyelitis vaccine and Haemophilus influenzae b conjugate (DTaP-IPV-Hib) vaccine coadministered at the 18-month vaccination were measured one month later. Safety data were collected.

RESULTS:

At 19 months of age, ≥96% in group 1 achieved protective titres for the four meningococcal serogroups after dose 2; 67% in group 2 exhibited protective titres against serogroup C 28 days after MCC vaccination at 12 months of age, declining to 27% seven months later. DTaP-IPV-Hib elicited high antibody concentrations/titres in groups 1 and 2, consistent with historical values. The safety profiles after each dose generated no unexpected safety signals; no serious adverse events were related to vaccination.

DISCUSSION:

A two-dose series of MenACYW-D given concomitantly with a DTaP-IPV-Hib booster dose at 18 months of age demonstrated a good immunogenicity and safety profile. A two-dose series of MenACYW-D can be used as an alternative to one dose of MCC and provides protection against additional serogroups (NCT ID: NCT01359449).  相似文献   
7.
A case of CD56/NCAM+ malignant lymphoma is reported. Only a rare malignant lymphoma cell showed azurophilic granules in the cytoplasm of Giesma-stained preparations, while electron microscopic examination revealed occasional cytoplasmic granules with paracrystalline inclusions. The most common phenotype seen in NK lymphomas, CD2+, CD3-, CD56+, CD16-, CD57-, was present in the case. Cases with this phenotype have been interpreted to represent either true NK lymphoma or T-cell lymphoma with NK expression. Genotyping, where performed, has shown TCR germline configuration. Our case showed TCRβ rearrangement indicating that the above phenotype can be associated with a peripheral T-cell lymphoma.  相似文献   
8.
The need for a patient-centered approach to health care services delivery is well recognized. Health care has become more specialized, with increasing numbers of disciplines and subdisciplines. In addition, both providers and community are increasingly mobile. As a consequence, patients see more providers, which has led to increasing fragmentation of patient-centered care and in particular of patients' personal health records. Clinicians and patients alike recognize the need to ensure that care information is patient-centered, continuous, and integrated in order to optimize the effectiveness of proactive and reactive care. Current arrangements, however, including the architecture of medical record and information management systems, are mainly provider- and service-centered and may not readily support the sharing of data to this end.  相似文献   
9.
c-Jun and the transcriptional control of neuronal apoptosis   总被引:17,自引:0,他引:17  
There has been considerable interest in the molecular mechanisms of apoptosis in mammalian neurons because this form of neuronal cell death is important for the normal development of the nervous system and because inappropriate neuronal apoptosis may contribute to the pathology of human neurodegenerative diseases. The aim of recent research has been to identify the key components of the cell death machinery in neurons and understand how the cell death programme is regulated by intracellular signalling pathways activated by the binding of neurotrophins or death factors to specific cell surface receptors. The aim of this commentary was to review research that has investigated the role of the Jun N-terminal kinase (JNK)/c-Jun signalling pathway in neuronal apoptosis, focusing in particular on work carried out with developing sympathetic neurons. Experiments with sympathetic neurons cultured in vitro, as well as with cerebellar granule neurons and differentiated PC12 cells, have demonstrated that JNK/c-Jun signalling can promote apoptosis following survival factor withdrawal. In addition, experiments with Jnk(-/-) knockout mice have provided evidence that Jnk3 may be required for apoptosis in the hippocampus in vivo following injection of kainic acid, an excitotoxin, and that Jnk1 and Jnk2 are required for apoptosis in the developing embryonic neural tube. However, in the embryonic forebrain, Jnk1 and Jnk2 have the opposite function and are necessary for the survival of developing cortical neurons. These results suggest that JNKs and c-Jun are important regulators of the cell death programme in the mammalian nervous system, but that their biological effects depend on the neuronal type and stage of development.  相似文献   
10.
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