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   327篇
  免费   11篇
儿科学   8篇
妇产科学   8篇
基础医学   21篇
口腔科学   2篇
临床医学   6篇
内科学   27篇
皮肤病学   4篇
神经病学   34篇
特种医学   4篇
外科学   58篇
预防医学   4篇
眼科学   150篇
药学   5篇
肿瘤学   7篇
  2021年   35篇
  2020年   13篇
  2019年   3篇
  2018年   7篇
  2017年   5篇
  2016年   7篇
  2015年   8篇
  2014年   15篇
  2013年   19篇
  2012年   21篇
  2011年   26篇
  2010年   12篇
  2009年   10篇
  2008年   17篇
  2007年   17篇
  2006年   16篇
  2005年   18篇
  2004年   16篇
  2003年   12篇
  2002年   14篇
  2001年   14篇
  2000年   9篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   5篇
  1991年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
排序方式: 共有338条查询结果,搜索用时 15 毫秒
1.
2.
PURPOSE: The lumbosacral cerebrospinal fluid (CSF) volume, as assessed by magnetic resonance imaging, is a major determinant of the intrathecal spread of local anesthetics. Ultrasound imaging of the lumbar spine allows measurement of dural sac dimensions, which we hypothesize can be used to estimate CSF volume. The purpose of this study was to investigate whether the dural sac antero-posterior diameter correlates with sensory levels of spinal anesthesia during elective Cesarean delivery (CD). METHODS: After Research Ethics Board approval and informed consent, a prospective observational study enrolled 41 patients scheduled for elective CD under spinal anesthesia. With ultrasound imaging (transverse approach, 2-5 MHz curved array probe), we measured the antero-posterior diameter of the lumbar dural sac (dural sac diameter, DSD). Spinal anesthesia was administered with 0.75% hyperbaric bupivacaine 1.6 mL, fentanyl 10 microg and morphine 100 microg, with the patient in the sitting position. Sensory block levels were assessed with ice and pinprick every five minutes until peak sensory levels (PSL) were attained. Spearman's rank correlation was used to correlate DSD with PSL and time to attain PSL. RESULTS: There were no significant correlations between DSD and PSL assessed with ice (P = 0.474) or pinprick (P = 0.583). Similarly, there was no significant correlation between DSD and time to reach PSL, and between DSD and patient demographics. CONCLUSION: The lumbar DSD, as determined by ultrasound, is not a predictor of spinal anesthesia spread. Further research is necessary to understand if ultrasound findings can be used to predict intrathecal spread of local anesthetics.  相似文献   
3.
4.
Sixty-four elderly patients who had been admitted to the St. George's Hospital Alzheimer's disease evaluation project during 1981-1989 were followed up to postmortem examination. Comparison between clinical diagnoses and neuropathological diagnoses indicated positive predictive values for the antemortem diagnoses of 50-67%. Existing clinical criteria may not be accurate enough to permit firm antemortem diagnosis of older people for either research or clinical purposes.  相似文献   
5.
The ultrastructure of the cells and capillaries of the frontal cortex and hippocampus was studied in marmosets to assess age-related changes. The appearances in the brains of four marmosets, more than 12 years of age, were compared with those of two young marmosets aged 26 and 21 months. There was widespread accumulation of lipofuscin in neurons, glial cells, perivascular macrophages and pericytes, but not in endothelial cells. Many of the nerve cell nuclei showed marked membrane infolding, alteration of nuclear morphology and occasional inclusions. A few degenerated and dystrophic axons containing abnormal organelles were seen. The capillaries displayed irregularly thickened and split basal laminae. No neurofibrillary tangles, neuritic plaques, amyloid deposits or granulovacuoles were present. These changes are compared to those occurring in other animal species and in man during ageing.  相似文献   
6.
Granulosa Cell Tumors (GCT) constitutes 1.5% to 3.5% of all primary ovarian neoplasms. They may be solid, cystic or both. Unilocular cystic GCT are very rare. We report here a case of 32 years female with unicystic GCT in which the distinction from follicular cyst was difficult and was made by carefully examining the lining of the cyst,which showed occasional multiple layers of granulosa cells with a few Call-Exner bodies.  相似文献   
7.
Retinoblastoma is the most common primary intraocular malignancy in children, caused by inactivation of the RB1 gene on chromosome 13. We carried out a mutational screen of the exons and promoter of the RB1 gene in Indian patients with retinoblastoma in order to determine the range of mutations giving rise to disease. Forty-seven patients were screened for mutations in all exons and promoter of the RB1 gene by single strand conformation polymorphism followed by sequencing. Tumors were available from 27 patients (12 bilateral and 15 unilateral retinoblastoma) while only peripheral blood was available from 20 patients, all with bilateral disease. Mutations were found in 22 patients, 9 from the analysis of tumors and 13 from peripheral blood. Eight novel mutations were identified, including 4 single base changes, 2 small deletions and 1 duplication. These are g.64365T>G (Tyr325Ter), g.78131G>A (Trp515Ter), g.150061G>T (Glu587Ter), g.170383C>G (S834X), g.41924A>C (IVS3-2A>C), g.150064ins4, g.160792del22, and g.76940del14 (IVS15 del +20-33). Almost all mutations produced nonsense codons or frameshifts. Recurrent mutations, especially at CpG sites were seen predominantly. Detectable mutations in exons were found in 46% of patients tested. Large deletions, epigenetic changes as well as mutations in non-coding regions may be the cause of disease in the remainder of patients. Knowledge of the full range of mutations can aid in the design of screening tests for individuals at risk.  相似文献   
8.
Lasers in Medical Science - Antimicrobial photodynamic therapy (APDT) is a promising approach for treatment of wounds infected with antibiotic-resistant bacteria. In this approach, delivery of...  相似文献   
9.
BackgroundNo Indian studies have assessed the implementation of recent policy on pharmacy based surveillance and its contribution in TB notification. So, this study was conducted with objectives to describe: a) pharmacy based TB surveillance and TB notification, and b) experiences of pharmacy based surveillance implementation from the programme managers and pharmacists perspective.MethodsA mixed methods study—quantitative (cross-sectional) and qualitative (in-depth interviews) in two selected districts Dharmapuri and Salem districts of Tamil Nadu State, India.ResultsIn 2018, 45 (11%) of 397 pharmacies in Dharmapuri and 90 (6%) of 1457 pharmacies in Salem districts reported sale of anti-TB drugs to 1307 and 1673 persons respectively. Upon validation through direct patient contact 942 (72%) persons in Dharmapuri and 863 (52%) persons were identified as previously ‘un-notified’ TB patients. These patients constituted 20% and 29% of the total TB cases notified in Dharmapuri and Salem respectively. The enablers for implementing this activity were: understanding the importance of notification, availability of resources (manpower, computers) to record, report and validate the patient data, repeated trainings and partnerships. The barriers were: patients' hesitancy to share their details to pharmacists (confidentiality), cumbersome recording and reporting process, difficulties in recording patient details during high workload busy business hours.ConclusionThis process contributed about one-fourth of the TB patients notified in these districts. Its implementation needs to be strengthened and should be scaled up in other parts of the country.  相似文献   
10.
E. coli AlkB, a repair enzyme of the dioxygenase family, catalyses the removal of mutagenic methylated nucleotides from the genome. Known for substrate promiscuity, AlkB''s catalytic mechanism and conformational changes accompanying substrate binding have been extensively dissected. However, the structural parameters of various substrates governing their recognition by AlkB still remain elusive. In this work, through solution-state vibrational spectra of methylated substrates bound to AlkB in combination with computational analysis, we show that the recognition specificity is dictated by the protonation states of the substrates. Specificity is conferred predominantly through hydrogen bonding and cation–π interactions. Furthermore, we report on the interaction of AlkB with normal, unmodified nucleotides, wherein the presence of an exocyclic amino group serves as an essential criterion for the initial process of substrate recognition. Taken together, these results provide a rationale for structural determinants of substrate specificity as well as mode of lesion discrimination employed by AlkB.

Positive charge on methylated nucleotides is a prime criterion for substrate recognition by E. coli AlkB.  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