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   1523篇
  免费   99篇
  国内免费   3篇
耳鼻咽喉   23篇
儿科学   82篇
妇产科学   45篇
基础医学   195篇
口腔科学   66篇
临床医学   130篇
内科学   249篇
皮肤病学   47篇
神经病学   78篇
特种医学   43篇
外科学   97篇
综合类   27篇
一般理论   1篇
预防医学   138篇
眼科学   44篇
药学   118篇
中国医学   3篇
肿瘤学   239篇
  2023年   16篇
  2022年   18篇
  2021年   46篇
  2020年   19篇
  2019年   50篇
  2018年   56篇
  2017年   48篇
  2016年   41篇
  2015年   47篇
  2014年   75篇
  2013年   74篇
  2012年   135篇
  2011年   119篇
  2010年   78篇
  2009年   50篇
  2008年   96篇
  2007年   90篇
  2006年   82篇
  2005年   73篇
  2004年   53篇
  2003年   57篇
  2002年   54篇
  2001年   13篇
  2000年   20篇
  1999年   17篇
  1998年   7篇
  1997年   7篇
  1996年   7篇
  1995年   5篇
  1994年   7篇
  1991年   11篇
  1990年   6篇
  1989年   12篇
  1988年   8篇
  1986年   7篇
  1985年   6篇
  1984年   6篇
  1983年   7篇
  1981年   7篇
  1979年   6篇
  1978年   5篇
  1977年   10篇
  1974年   4篇
  1973年   7篇
  1972年   6篇
  1971年   8篇
  1970年   5篇
  1968年   6篇
  1967年   4篇
  1966年   12篇
排序方式: 共有1625条查询结果,搜索用时 31 毫秒
31.
Correctly folded virus-like particles (VLPs) of papillomavirus (PV) display conformationally dependent epitopes that are type specific, maintained on authentic virions, and induce neutralizing antibodies. Alignment of the L1 amino acid (aa) sequences of 84 PVs revealed that the lengths of their N-termini are diverse and that multiple, possible initiation methionine (met) codons exist. The L1 gene of MusPV (MmuPV1), that naturally infects immunodeficient laboratory mouse strain (NMRI-Foxn1nu/Foxn1nu), has four met codons at the 1st, 2nd, 28th, and 30th aas from its N-terminus. Of these, the 3rd and 4th mets, that are at the 28th and 30th aa position from the N-termius, respectively, are located at the position where most PVs have their first met. These two mets, located at the 9th and 11th from the YLPP conserved aas of most PVs, should be considered as consensus initiation codons of PV L1s. Three L1 proteins of MusPV, starting from the 2nd, 3rd, and 4th mets, were expressed using a baculovirus expression system and characterized for their ability to self-assemble into VLPs. While MusPV L1 proteins starting from the 2nd met expressed an L1 protein that did not fold into VLPs, the L1s starting from the 3rd and 4th mets generated correct VLPs in abundant quantities. We now conclude that the highest quantity and best quality VLPs are made from the consensus L1 met of MusPV.  相似文献   
32.
33.
It is clear that the widespread and injudicious use of antimicrobials has greatly increased the presence of MDROs that threaten the health of all. There is worldwide acknowledgement that this threat is growing, and that prudent use of antimicrobials combined with infection prevention can prevent harm and improve patient safety. Antimicrobial stewardship programs must harness the talents of all members of the health care team to effectively identify the organism, determine its susceptibility, institute any precautions required, and prescribe the narrowest-acting antibiotic that will destroy it. IPs/HEs play a pivotal role in this approach, by assisting with early organism and infected patient identification, by promoting compliance with standard and transmission-based precautions and other infection prevention strategies such as care bundle practices, hand hygiene, and by educating staff, patients, and visitors.  相似文献   
34.
35.
A venue-based HIV prevention study which included Voluntary Counseling and Testing (VCT) was conducted in three diverse areas of Kenya-Malindi, Nanyuki and Rachounyo. Aims of the study were to: (1) assess the acceptability of VCT for the general population, men who have sex with men (MSM), and injecting drug users (IDUs) within the context of a venue-based approach; (2) determine if there were differences between those agreeing and not agreeing to testing; and (3) study factors associated with being HIV positive. Approximately 98% of IDUs and 97% of MSM agreed to VCT, providing evidence that populations with little access to services and whose behaviors are stigmatized and often considered illegal in their countries can be reached with needed HIV prevention services. Acceptability of VCT in the general population ranged from 60% in Malindi to 48% in Nanyuki. There were a few significant differences between those accepting and declining testing. Notably in Rachuonyo and Malindi those reporting multiple partners were more likely to accept testing. There was also evidence that riskier sexual behavior was associated with being HIV positive for both men in Rachounyo and women in Malindi. Overall HIV prevalence was higher among the individuals in this study compared to individuals sampled in the 2008-2009 Kenya Demographic and Health Survey, indicating the method is an appropriate means to reach the highest risk individuals including stigmatized populations.  相似文献   
36.
37.
To study the association between vitamin D receptor (VDR) gene polymorphisms and bone mass indices in adolescent girls, a cross-sectional study was conducted in 120 post-menarchal girls aged 15–18 years in Pune city, India. Serum levels of ionised calcium, inorganic phosphorous, parathyroid hormone and 25-hydroxy vitamin-D were measured. Bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) were measured at total body (TB), lumbar spine (LS) and left femoral neck (FN) using dual energy X-ray absorptiometry. Polymorphisms of the VDR gene at the Fok1 and Bsm1 loci were detected using SYBR Green quantitative polymerase chain reaction. The overall distribution of genotypes at the Bsm1 locus in this study was 33.3 % Bb, 29.2 % bb and 37.5 % BB while that for the Fok1 locus was 44.2 % Ff, 7.5 % ff and 48.3 % FF. There were no significant differences in the blood parameters when classified according to Bsm1 or Fok1 genotypes. Subjects with BB genotype have significantly higher mean TBBMC, TBBA, TBBMD and LSBMD than Bb and bb (p < 0.05) and showed a tendency for association with LSBMC and LSBA (p < 0.1). Subjects with Ff genotype showed a tendency for association with left FNBMC and FNBA (p < 0.1). Bsm1 genotype did not show an association with FN bone indices whereas Fok1 genotype did not show association with TB or LS bone indices. In conclusion, the present study demonstrates VDR gene polymorphism, defined by Bsm1 genotype, has an influence on total body and lumbar spine bone mass indices in post-menarchal Indian girls.  相似文献   
38.
Malignant transformation of the epithelial component of Warthin's tumor is extremely rare. We describe our experience of mucoepidermoid carcinoma arising in Warthin's tumor of the parotid gland in a 35 year old female. The tumor removed from the parotid region was well encapsulated and histologically comprised ofmucoepidermoid carcinoma along with areas of Warthin's tumor. The pathogenesis and differential diagnosis of this rare occurrence have been discussed.  相似文献   
39.
40.

Objective

To test the hypothesis that fluid resuscitation in the ED with plasmalyte-148 (PL) compared with 0.9% sodium chloride (SC) would result in a lower proportion of patients with diabetic ketoacidosis (DKA) requiring intensive care unit (ICU) admission.

Methods

We performed a prespecified nested cohort study at two hospitals within a cluster, crossover, open label, randomised, controlled trial comparing the effects of PL versus SC as fluid therapy for patients who presented to the ED with DKA. All patients presenting within a fixed recruitment period were included. The primary outcome was the proportion of patients admitted to ICU.

Results

Eighty-four patients were enrolled (SC n = 38, PL n = 46). The SC group had a lower median pH on admission (SC: 7.09 [interquartile range (IQR) 7.01–7.21], PL: 7.17 [IQR 6.99–7.26]). The median volume of intravenous fluids administered in ED was 2150 mL (IQR 2000–3200 mL; SC) and 2200 mL (IQR 2000–3450; PL); respectively. A higher proportion of patients in the SC group, 19 (50%), was admitted to ICU compared with PL group, 18 (39.1%); however, after adjustment for pH at presentation and diabetes type in a multivariable logistic regression model, the PL group did not have a significantly different rate of ICU admission compared with the SC group (odds ratio for ICU admission 0.73, 95% confidence interval 0.13–3.97, P = 0.71).

Conclusion

Patients with DKA treated with PL compared with SC in the EDs had similar rates of requiring ICU admission.  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