全文获取类型
收费全文 | 5006篇 |
免费 | 368篇 |
国内免费 | 58篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 286篇 |
妇产科学 | 102篇 |
基础医学 | 613篇 |
口腔科学 | 75篇 |
临床医学 | 370篇 |
内科学 | 1106篇 |
皮肤病学 | 93篇 |
神经病学 | 266篇 |
特种医学 | 291篇 |
外科学 | 476篇 |
综合类 | 332篇 |
一般理论 | 5篇 |
预防医学 | 405篇 |
眼科学 | 98篇 |
药学 | 387篇 |
中国医学 | 75篇 |
肿瘤学 | 410篇 |
出版年
2023年 | 43篇 |
2022年 | 74篇 |
2021年 | 144篇 |
2020年 | 77篇 |
2019年 | 78篇 |
2018年 | 98篇 |
2017年 | 115篇 |
2016年 | 125篇 |
2015年 | 128篇 |
2014年 | 188篇 |
2013年 | 241篇 |
2012年 | 284篇 |
2011年 | 265篇 |
2010年 | 217篇 |
2009年 | 193篇 |
2008年 | 205篇 |
2007年 | 259篇 |
2006年 | 207篇 |
2005年 | 192篇 |
2004年 | 175篇 |
2003年 | 171篇 |
2002年 | 125篇 |
2001年 | 127篇 |
2000年 | 106篇 |
1999年 | 92篇 |
1998年 | 109篇 |
1997年 | 89篇 |
1996年 | 85篇 |
1995年 | 67篇 |
1994年 | 67篇 |
1993年 | 63篇 |
1992年 | 74篇 |
1991年 | 62篇 |
1990年 | 64篇 |
1989年 | 66篇 |
1988年 | 69篇 |
1987年 | 44篇 |
1986年 | 63篇 |
1985年 | 58篇 |
1984年 | 31篇 |
1983年 | 37篇 |
1982年 | 24篇 |
1979年 | 33篇 |
1977年 | 25篇 |
1976年 | 30篇 |
1975年 | 31篇 |
1973年 | 31篇 |
1972年 | 36篇 |
1970年 | 27篇 |
1968年 | 26篇 |
排序方式: 共有5432条查询结果,搜索用时 15 毫秒
71.
This is the case of an Indian woman who was hospitalized after a diagnosis of chronic inversion of the uterus with a vesicovaginal fistula. She suffered from urinary incontinence for 40 years, the condition having developed following a difficult labor. Ultimately, she proved to have a complete inversion of the bladder through a vesicovaginal fistula. 相似文献
72.
S. K. Bandyopadhyay R. K. Tiwari A. Mitra B. Mukherjee A. Banerjee G. C. Chatterjee 《Archives of toxicology》1982,50(3-4):227-232
Chronic dieldrin administration to rats (5 mg/kg/day) produced pathological changes in liver and kidney tissues. Dieldrin treated rats showed high levels of liver ascorbic acid and increased activities of inorganic pyrophosphatase in brain and glucose-6-phosphatase in liver. The activities of Mg2+-ATPase in liver and acetylcholinesterase in brain were decreased under toxic doses of dieldrin. L-Ascorbic acid supplements in treated animals could partially prevent the pathological alterations, as observed histologically in liver and kidney tissues. Administration of this vitamin could also prevent alterations in some enzyme activities produced by toxic dieldrin doses. 相似文献
73.
74.
75.
Formal retrospective case review and sudden infant death 总被引:2,自引:0,他引:2
A review of 24 consecutive sudden infant deaths was undertaken to evaluate the importance of the various stages in the postmortem assessment of such cases. Death in three cases was caused by obvious trauma. Of the remainder, 16 were attributed to sudden infant death syndrome (SIDS), 4 to accidental asphyxia (identified by death scene examination and/or formal case review) and 1 to a lingual thyroglossal duct cyst. Three (14%) of 21 deaths thought to be SIDS after postmortem examination were attributed to asphyxia following subsequent formal case review. 相似文献
76.
It is widely believed that the improved survival of young people with chronic diseases will be associated with the development of appropriate services within the adult healthcare domain. There is, however, little evidence to suggest that this is happening at a rate commensurate with clinical requirements. This paper highlights the multiplicity of barriers that impede the development of transition services to facilitate the transfer of medical care from the paediatric to the adult domain. Different models of transition care are described, and the terms 'transfer' and 'transition' are differentiated. The clinical demand for service development is highlighted, as well as the need for specific research in this area of healthcare delivery. 相似文献
77.
SK Roy AM Tomkins SM Akramuzzaman RH Behrens R Haider D Mahalanabis G Fuchs 《Archives of disease in childhood》1997,77(3):196-200
OBJECTIVE: To evaluate the impact of zinc supplementation on the clinical course, stool weight, duration of diarrhoea, changes in serum zinc, and body weight gain of children with acute diarrhoea. DESIGN: Randomised double blind controlled trial. Children were assigned to receive zinc (20 mg elemental zinc per day) containing multivitamins or control group (zinc-free multivitamins) daily in three divided doses for two weeks. SETTING: A diarrhoeal disease hospital in Dhaka, Bangladesh. PATIENTS: 111 children, 3 to 24 months old, below 76% median weight for age of the National Center for Health Statistics standard with acute diarrhoea. Children with severe infection and/or oedema were excluded. MAIN OUTCOME MEASURES: Total diarrhoeal stool output, duration of diarrhoea, rate of weight gain, and changes in serum zinc levels after supplementation. RESULTS: Stool output was 28% less and duration 14% shorter in the zinc supplemented group than placebo (p = 0.06). There were reductions in median total diarrhoeal stool output among zinc supplemented subjects who were shorter (less than 95% height for age), 239 v 326 g/kg (p < 0.04), and who had a lower initial serum zinc (< 14 mmol/l), 279 v 329 g/kg (p < 0.05); a shortening of mean time to recovery occurred (4.7 v 6.2 days, p < 0.04) in those with lower serum zinc. There was an increase in mean serum zinc in the zinc supplemented group (+2.4 v -0.3 mumol/l, p < 0.001) during two weeks of supplementation, and better mean weight gain (120 v 30 g, p < 0.03) at the time of discharge from hospital. CONCLUSIONS: Zinc supplementation is a simple, acceptable, and affordable strategy which should be considered in the management of acute diarrhoea and in prevention of growth faltering in children specially those who are malnourished. 相似文献
78.
WG Mitchell H Lynn JF Bale MA Maeder SM Donfield B Garg AH Tilton JK Willis TP Bohan 《Pediatrics》1997,100(5):817-824
BACKGROUND: Boys and young men with hemophilia treated with factor infusions before 1985 had a substantial risk of acquiring the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome. This study was designed to assess the effects of HIV and hemophilia per se on neurological function in a large cohort of subjects with hemophilia, and to investigate the relationships between neurological disease and death during follow-up. METHODS: Three hundred thirty-three boys and young men (207 HIV seropositive and 126 HIV seronegative) were evaluated longitudinally in a multicenter, multidisciplinary study. Neurological history and examination were conducted at baseline and annually for 4 years. The relationship between neurological variables, HIV serostatus, CD4+ cell counts, and vital status at the conclusion of the study was examined using logistic regression models. RESULTS: The risks of nonhemophilia-associated muscle atrophy, behavior change, and gait disturbance increased with time in immune compromised HIV-seropositive subjects compared with HIV seronegative or immunologically stable HIV-seropositive subjects. The risk of behavior change in immune compromised HIV-seropositive hemophiliacs, for example, rose to 60% by year 4 versus 10% to 17% for the other study groups. Forty-five subjects (13.5%), all of whom were HIV seropositive, died by year 4. Subjects who died had had increased risks of hyperreflexia, nonhemophilia-associated muscle atrophy, and behavior change. CONCLUSIONS: These results indicate that immune compromised, HIV-seropositive hemophiliacs have high rates of neurological abnormalities over time and that neurological abnormalities were common among subjects who later died. By contrast, immunologically stable HIV-seropositive subjects did not differ from the HIV-seronegative participants. Hemophilia per se was associated with progressive abnormalities of gait, coordination, and motor function. 相似文献
79.
Kangaroo Care with a ventilated preterm infant 总被引:4,自引:0,他引:4
80.
The hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in 6-
thioguanine (TG) resistant T-lymphocytes is a useful target for the study
of somatic in vivo mutagenesis, since it provides information about a broad
spectrum of mutation. Mutations in the hprt coding region were studied in
124 TG-resistant T-cell clones from 38 healthy, non- smoking male donors
from a previously studied population of bus maintenance workers,
fine-mechanics and laboratory personnel. Their mean age was 43 years (range
23-64) and their hprt mutant frequency was 9.3 +/- 5.2 x 10(-6) (mean +/-
SD, range 1.4-22.6 x 10(-6)). Sequence analysis of hprt cDNA identified 115
unique mutations; 76% were simple base substitutions, 10% were +/-1 bp
frameshifts, and 10% were small deletions within exons (3-52 bp). In
addition, two tandem base substitutions and one complex mutation were
observed. Simple base substitutions were observed at 55 (20%) of 281 sites
known to be mutable in the hprt coding sequence. The distribution of these
mutations was significantly different than would be expected based upon a
Poisson distribution (P < 0.0001), suggesting the existence of
'hotspots'. All of the 87 simple base substitutions occurred at known
mutable sites, but eight were substitutions of a kind that have not
previously been reported at these sites. The most frequently mutated sites
were cDNA positions 197 and 146, with six and five independent mutations
respectively. Four mutations were observed at position 131, and three each
at positions 143, 208, 508 and 617. Transitions (52%) were slightly more
frequent than tranversions (48%), and mutations at GC base pairs (56%) more
common than mutations at AT base pairs (44%). GC > AT was the most
common type of base pair substitution (37%). The majority of the mutations
at GC base pairs (78%) occurred at sites with G in the non-transcribed
strand. All but one of eight mutations at CpG- sites were of the kind
expected from deamination of methylated cytosine. Deletion of a single base
pair (-1 frameshift) was three times more frequent than insertion of a
single bp (+1 frameshift). Almost half (6/13) of the small (3-52 bp)
deletions within the coding sequence clustered in the 5' end of exon 2.
Short repeats and other sequence motifs that have been associated with
replication error were found in the flanking regions of most of the
frameshifts and small deletions. However, several differences in the local
sequence context between +/-1 frameshift and deletion mutations were also
noticed. The present results identify positions 197, 146 and possibly 131
as hotspots for base substitution mutations, and confirm previously
reported hotspots at positions 197, 508 and 617. In addition, the earlier
notion of a deletion hotspot in the 5'end of exon 2 was confirmed. The
observations of these mutational cluster regions in different human
populations suggest that they are due to endogeneous mechanisms of
mutagenesis, or to ubiquitous environmental influences. The emerging
background spectrum of somatic in vivo mutation in the human hprt gene
provides a useful basis for comparisons with radiation or chemically
induced mutational spectra, as well as with gene mutations in human tumors.
相似文献