全文获取类型
收费全文 | 546篇 |
免费 | 33篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 32篇 |
妇产科学 | 8篇 |
基础医学 | 81篇 |
口腔科学 | 9篇 |
临床医学 | 37篇 |
内科学 | 82篇 |
皮肤病学 | 21篇 |
神经病学 | 11篇 |
特种医学 | 139篇 |
外科学 | 63篇 |
综合类 | 20篇 |
预防医学 | 30篇 |
眼科学 | 6篇 |
药学 | 22篇 |
肿瘤学 | 30篇 |
出版年
2021年 | 6篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 13篇 |
2014年 | 8篇 |
2013年 | 11篇 |
2012年 | 4篇 |
2011年 | 16篇 |
2010年 | 25篇 |
2009年 | 31篇 |
2008年 | 16篇 |
2007年 | 24篇 |
2006年 | 20篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2001年 | 18篇 |
2000年 | 9篇 |
1999年 | 2篇 |
1998年 | 20篇 |
1997年 | 36篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 16篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 17篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 13篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1966年 | 4篇 |
1965年 | 2篇 |
排序方式: 共有592条查询结果,搜索用时 0 毫秒
101.
102.
PK Tran A Haworth F Foroudi A Paneghel AG Herschtal KH Tai SG Williams S Soteriou M Laferlita GM Duchesne 《Journal of Medical Imaging and Radiation Oncology》2009,53(6):574-580
The aim of this study is to prospectively evaluate and model surrogate explanatory variables (SEVs) of target coverage and rectal dose pertaining to soft tissue anatomy visualised on cone beam computed tomography (CBCT) for incorporation into post‐prostatectomy treatment coverage verification protocols. Twenty post‐prostatectomy patients treated with conformal prostate bed radiotherapy (64–74 Gy) underwent CBCT daily at fractions 1 to 5, and then weekly. Treatment coverage was defined on each CBCT using ‘PTV95’, percentage of the CBCT PTV covered by original treatment fields, and ‘RECTD50’, dose delivered to 50% of CBCT rectal volume by original treatment fields. Three candidate SEVs for treatment coverage were defined for each scan: anterior rectal wall movement, change in bladder length and bladder base movement. Both anterior rectal wall movement and increase in bladder length predicted for the decreased PTV95 (P < 0.001 for each). Anterior movement of the anterior rectal wall predicted for increased RECTD50 (P < 0.001). Predictive models for the PTV95 and RECTD50 that accept the significant SEVs as inputs were developed. We developed simple CBCT‐acquired soft tissue anatomic surrogate measures that signal changes in target coverage and rectal dose during post‐prostatectomy radiotherapy. Conventional bony anatomy patient position verification protocols were inadequate in accounting for soft tissue target and organ variation seen with CBCT. 相似文献
103.
BackgroundNational Institute for Health and Clinical Excellence guidelines (CG87) recommend neutral protamine hagedorn (NPH) insulin for the provision of basal insulin in type 2 diabetes, but use of analogue insulin is as much as 40%. Where residual endogenous insulin secretory capacity is present there is no evidence that analogue insulins provide any additional benefit over human insulins, and they come at an expensive premium. Anecdotally, however, there is a reluctance to switch people back to NPH insulin, partly because of a perceived risk of pancreatic failure and potential ketosis. Urinary C-peptide creatinine ratio (UCPCR) has been validated as a method for evaluating residual endogenous insulin secretion in type 1 and type 2 diabetes, with a UCPCR of no more than 0·2 nmol/mmol suggestive of absolute insulin deficiency. We aimed to evaluate the prevalence of true insulin deficiency among patients with type 2 diabetes with UCPCR, and confirm findings with the gold standard mixed meal tolerance test (MMTT).Methods191 insulin-treated patients with a clinical diagnosis of type 2 diabetes (diagnosed at or after age 45 years and who did not start insulin within the first year of diagnosis) collected a 2-h post-prandial urine sample for UCPCR measurement. Nine patients from two subgroups (UCPCR ≤0·2 nmol/mmol and UCPCR >0·2) completed a standard MMTT.Findings11 (5·8%) of 191 patients had two consistent UCPCRs of less than or equal to 0·2 nmol/mmol. Nine were able to do the MMTT, of whom five were confirmed to have absolute insulin deficiency (stimulated serum c-peptide <0·2 nmol/L). Three of these five patients were glutamic acid decarboxylase antibody-negative. Nine of nine patients with UCPCR of more than 0·2 nmol/L had confirmed endogenous insulin secretion in their MMTT. Those with insulin deficiency had a shorter time to starting insulin (median 2·5 years [IQR 1·5–3·0] vs 6·0 [3·0–10·75], p=0·005) and lower body-mass index (25 kg/m2 vs 29, p=0·04) but no other significant differences in clinical characteristics.InterpretationWe have demonstrated a very low prevalence of true pancreatic failure in this population of insulin-treated patients with type 2 diabetes. This requires further exploration by comparison of a population being treated with NPH insulin with one on analogue insulin, and then determining whether UCPCR could act as a clinical decision support tool to safely switch from analogue insulin to NPH insulin.FundingNational Institute for Health Research. 相似文献
104.
Ghosh D; Stewart DR; Nayak NR; Lasley BL; Overstreet JW; Hendrickx AG; Sengupta J 《Human reproduction (Oxford, England)》1997,12(5):914-920
The present study was undertaken to assess the temporal association between
the profiles of serum concentrations of oestradiol-17beta, progesterone,
chorionic gonadotrophin (CG) and relaxin in pregnancies established
naturally, and after embryo transfer, as well as in failed pregnancies in
rhesus monkeys. In naturally mated cycles (group 1) a conception rate of
75% was obtained. In group 1, the mean day of CG detection in serum was
11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day
post-ovulation. In group 2, embryo transfer to synchronous, non-mated
surrogate recipients was performed; seven embryo transfer cycles yielded
three pregnancies which were allowed to continue to term and normal infants
were delivered. In embryo transfer cycles the mean day of CG detection was
14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day
post-ovulation. A delay of about 3 days was observed in the appearance in
circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between
natural mated and embryo transfer conception cycles. Significant
differences (P < 0.05 for progesterone and P < 0.03 for oestradiol)
were obtained for the areas under the curves for progesterone and
oestradiol between days 12 and 16 in conception cycles compared with failed
pregnancies. These data provide the first observation of the normal
hormonal signals associated with maternal recognition of transferred
embryos during the peri- implantation period, and suggest that the use of
such an experimental primate embryo transfer model may help to elucidate
components of maternal and embryonic signal-response mechanisms during
embryo implantation.
相似文献
105.
Laassri M Bidzhieva B Speicher J Pletnev AG Chumakov K 《Journal of medical virology》2011,83(5):910-920
Genetic stability is an important characteristic of live viral vaccines because an accumulation of mutants can cause reversion to a virulent phenotype as well as a loss of immunogenic properties. This study was aimed at evaluating the genetic stability of a live attenuated West Nile (WN) virus vaccine candidate that was generated by replacing the pre-membrane and envelope protein genes of dengue 4 virus with those from WN. Chimeric virus was serially propagated in Vero, SH-SY5Y human neuroblastoma and HeLa cells and screened for point mutations using hybridization with microarrays of overlapping oligonucleotide probes covering the entire genome. The analysis revealed several spontaneous mutations that led to amino acid changes, most of which were located in the envelope (E) and non-structural NS4A, NS4B, and NS5 proteins. Viruses passaged in Vero and SH-SY5Y cells shared two common mutations: G(2337) C (Met(457) Ile) in the E gene and A(6751) G (Lys(125) Arg) in the NS4A gene. Quantitative assessment of the contents of these mutants in viral stocks indicated that they accumulated independently with different kinetics during propagation in cell cultures. Mutant viruses grew better in Vero cells compared to the parental virus, suggesting that they have a higher fitness. When tested in newborn mice, the cell culture-passaged viruses did not exhibit increased neurovirulence. The approach described in this article could be useful for monitoring the molecular consistency and quality control of vaccine strains. 相似文献
106.
Z Kibar S Salem CM Bosoi E Pauwels P De Marco E Merello AG Bassuk V Capra P Gros 《Clinical genetics》2011,80(1):76-82
Kibar Z, Salem S, Bosoi CM, Pauwels E, De Marco P, Merello E, Bassuk AG, Capra V, Gros P. Contribution of VANGL2 mutations to isolated neural tube defects. Vangl2 was identified as the gene defective in the Looptail (Lp) mouse model for neural tube defects (NTDs). This gene forms part of the planar cell polarity (PCP) pathway, also called the non‐canonical Frizzled/Dishevelled pathway, which mediates the morphogenetic process of convergent extension essential for proper gastrulation and neural tube formation in vertebrates. Genetic defects in PCP signaling have strongly been associated with NTDs in mouse models. To assess the role of VANGL2 in the complex etiology of NTDs in humans, we resequenced this gene in a large multi‐ethnic cohort of 673 familial and sporadic NTD patients, including 453 open spina bifida and 202 closed spinal NTD cases. Six novel rare missense mutations were identified in seven patients, five of which were affected with closed spinal NTDs. This suggests that VANGL2 mutations may predispose to NTDs in approximately 2.5% of closed spinal NTDs (5 in 202), at a frequency that is significantly different from that of 0.4% (2 in 453) detected in open spina bifida patients (p = 0.027). Our findings strongly implicate VANGL2 in the genetic causation of spinal NTDs in a subset of patients and provide additional evidence for a pathogenic role of PCP signaling in these malformations. 相似文献
107.
Dr. M. Wojcinski U. Freitag C. Hösemann H. Perlitz AG Impfen in der Gynäkologie des Berufsverbandes der Frauenärzte e. V. 《Der Gyn?kologe》2014,47(10):791-814
Diseases which can be prevented by vaccination and the indications for vaccination are described in detail with a special focus on aspects relevant for the gynecological and obstetric practice. The article also gives the billing numbers for Germany which are necessary for the remuneration. With this vaccinations can be implemented in the routine daily practice. The gynecologist entrusted by the patient can provide vaccination protection in all phases of life, if necessary even during pregnancy and provide neonates with maternal passive immunity. 相似文献
108.
109.
The ability of the monocyte monolayer assay (MMA) and the chemiluminescence test (CLT) to predict the clinical significance of alloantibodies associated with hemolytic disease of the newborn (HDN) was assessed by the use of 22 well-characterized antisera– predominantly anti-D–from alloimmunized pregnant women. Seventeen sera were obtained before delivery from women whose infants were antigen positive for the antibody specificities identified in the maternal serum. With testing of these 17 sera by MMA, 10 results were in agreement with the presence or absence of HDN, but there were 5 false- positive and 2 false-negative results. With the CLT, 16 results were in agreement with the presence or absence of HDN, and there was 1 false- negative result. Five sera were obtained from women whose infants were antigen negative for the antibody specificities identified in the maternal serum. The CLT and the MMA were both subject to false-positive results with these sera. These results suggest that the CLT may be more valuable than the MMA as a noninvasive test for predicting the clinical significance of alloantibodies in HDN. 相似文献
110.
Interpretation of CT scans with PACS image display in stack mode 总被引:4,自引:0,他引:4