全文获取类型
收费全文 | 4120篇 |
免费 | 240篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 116篇 |
妇产科学 | 65篇 |
基础医学 | 416篇 |
口腔科学 | 137篇 |
临床医学 | 462篇 |
内科学 | 1091篇 |
皮肤病学 | 129篇 |
神经病学 | 295篇 |
特种医学 | 310篇 |
外科学 | 534篇 |
综合类 | 51篇 |
一般理论 | 1篇 |
预防医学 | 319篇 |
眼科学 | 40篇 |
药学 | 239篇 |
中国医学 | 9篇 |
肿瘤学 | 163篇 |
出版年
2023年 | 21篇 |
2022年 | 37篇 |
2021年 | 74篇 |
2020年 | 44篇 |
2019年 | 48篇 |
2018年 | 73篇 |
2017年 | 82篇 |
2016年 | 74篇 |
2015年 | 94篇 |
2014年 | 126篇 |
2013年 | 185篇 |
2012年 | 204篇 |
2011年 | 202篇 |
2010年 | 145篇 |
2009年 | 164篇 |
2008年 | 159篇 |
2007年 | 193篇 |
2006年 | 180篇 |
2005年 | 151篇 |
2004年 | 134篇 |
2003年 | 130篇 |
2002年 | 149篇 |
2001年 | 106篇 |
2000年 | 83篇 |
1999年 | 98篇 |
1998年 | 106篇 |
1997年 | 98篇 |
1996年 | 98篇 |
1995年 | 59篇 |
1994年 | 78篇 |
1993年 | 59篇 |
1992年 | 59篇 |
1991年 | 61篇 |
1990年 | 66篇 |
1989年 | 83篇 |
1988年 | 64篇 |
1987年 | 66篇 |
1986年 | 54篇 |
1985年 | 56篇 |
1984年 | 44篇 |
1983年 | 22篇 |
1982年 | 28篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 38篇 |
1978年 | 24篇 |
1977年 | 20篇 |
1976年 | 30篇 |
1975年 | 24篇 |
1973年 | 20篇 |
排序方式: 共有4412条查询结果,搜索用时 812 毫秒
61.
Is the outcome of in-vitro fertilization and embryo transfer treatment improved by spontaneous or surgical drainage of a hydrosalpinx? 总被引:4,自引:7,他引:4
Sowter MC; Akande VA; Williams JA; Hull MG 《Human reproduction (Oxford, England)》1997,12(10):2147-2150
A pilot study was designed to examine whether the outcome of embryo
transfer in women with a hydrosalpinx might be improved by surgical
drainage of the hydrosalpinx at the time of oocyte collection for in- vitro
fertilization treatment. A comparative, controlled but retrospective
analysis of the results was performed of all women with infective tubal
damage aged <40 years old, who had ovulatory cycles, a normal uterus and
a partner with normal spermatozoa. A standardized treatment regimen was
used. A maximum of three embryos were transferred. Hydrosalpinx was defined
by prior hysterosalpingography and/or laparoscopy with transcervical dye
injection. A total of 237 embryo transfer cycles in women with
hydrosalpinges (tubal distension not visible in 151, visible but not
drained in 30 and drained in 56) were compared with 705 embryo transfer
cycles in women with tubal disease but no hydrosalpinx. Results were
analysed in the first three cycles but also separately in the first cycle
to check for bias. Success rates were higher in the first cycle, but did
not significantly influence overall differences. Implantation rates were
significantly reduced overall in the hydrosalpinx group (8.0 versus 13.2%
for controls; P < 0.001), being 8.3% (P < 0.01) in the subgroup
without evident tubal distension and 7.5% (not significant) in the drained
hydrosalpinx group. This study shows that tubal damage with distal
occlusion is associated with a marked reduction in embryo implantation,
even in the absence of obvious fluid distension. Surgical drainage of
distended hydrosalpinges appears to offer no benefit.
相似文献
62.
Clinical significance of serum hepatitis C virus (HCV) RNA as marker of HCV infection. 总被引:1,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M G Marin S Bresciani M Puoti A Rodella A Gussago A Ravaggi G Pizzocolo A Albertini E Cariani 《Journal of clinical microbiology》1994,32(12):3008-3012
We have evaluated the clinical significance of hepatitis C virus (HCV) RNA determination by analyzing a group of 221 hospitalized patients with abnormal liver function tests. Serum HCV RNA was detected by "nested" PCR amplification followed by nonisotopic hybridization. Of the 200 (90.5%) patients with anti-HCV-positive enzyme-linked immunosorbent assay results, 152 (76%) were RIBA reactive, 47 (23.5%) had indeterminate results, and 1 (0.5%) was nonreactive. Of the 180 (90%) patients positive for anti-HCV and HCV RNA, 138 (76.7%) were RIBA reactive and 42 (23.3%) were RIBA indeterminate. The pattern of RIBA reactivity did not correlate with the presence of HCV RNA. Elevated alanine aminotransferase levels were associated neither with the presence of viremia nor with the RIBA pattern. Histological findings consistent with non-A non-B hepatitis correlated with the presence of HCV RNA but not with the RIBA pattern. HCV RNA was detected in 11 of 21 (52.4%) anti-HCV-negative patients. These 11 patients were either immunosuppressed or in the prodromic phase of acute hepatitis C. Circulating HCV RNA can therefore be described as being predictive of virus-induced liver damage in anti-HCV-positive patients and may be useful in the diagnosis of HCV infection in anti-HCV-negative immunosuppressed patients or in those with early acute infection. 相似文献
63.
Canfield MC; Tamarappoo BK; Moses AM; Verkman AS; Holtzman EJ 《Human molecular genetics》1997,6(11):1865-1871
Congenital nephrogenic diabetes insipidus (NDI) is a rare disease caused
most often by mutations in the vasopressin V2 receptor (AVPR2). We studied
a family which included a female patient with NDI with symptoms dating from
infancy. The patient responded to large doses of desmopressin (dDAVP) which
decreased urine volume from 10 to 4 I/day. Neither the parents nor the
three sisters were polyuric. The patient was found to be a compound
heterozygote for two novel recessive point mutations in the aquaporin-2
(AQP2) gene: L22V in exon 1 and C181W in exon 3. Residue Cys181 in AQP2 is
the site for inhibition of water permeation by mercurial compounds and is
located near to the NPA motif conserved in all aquaporins. Osmotic water
permeability (Pf) in Xenopus oocytes injected with cRNA encoding C181W-AQP2
was not increased over water control, while expression of L22V cRNA
increased the Pf to approximately 60% of that for wild-type AQP2.
Co-injection of the mutant cRNAs with the wild-type cRNA did not affect the
function of the wild-type AQP2. Immunolocalization of AQP2-transfected CHO
cells showed that the C181W mutant had an endoplasmic reticulum-like
intracellular distribution, whereas L22V and wild-type AQP2 showed endosome
and plasma membrane staining. Water permeability assays showed a high Pf in
cells expressing wild-type and L22V AQP2. This study indicates that AQP2
mutations can confer partially responsive NDI.
相似文献
64.
The role of size, sequence and haplotype in the stability of FRAXA and FRAXE alleles during transmission 总被引:2,自引:5,他引:2
Murray A; Macpherson JN; Pound MC; Sharrock A; Youings SA; Dennis NR; McKechnie N; Linehan P; Morton NE; Jacobs PA 《Human molecular genetics》1997,6(2):173-184
Factors involved in the stability of trinucleotide repeats during
transmission were studied in 139 families in which a full mutation,
premutation or intermediate allele at either FRAXA or FRAXE was
segregating. The transmission of alleles at FRAXA, FRAXE and four
microsatellite loci were recorded for all individuals. Instability within
the minimal and common ranges (0-40 repeats for FRAXA, 0-30 repeats for
FRAXE) was extremely rare; only one example was observed, an increased in
size at FRAXA from 29 to 39 repeats. Four FRAXA and three FRAXE alleles in
the intermediate range (41-60) repeats for FRAXA, 31-60 for FRAXE) were
unstably transmitted. Instability was more frequent for FRAXA intermediate
alleles that had a tract of pure CGG greater than 37 although instability
only occurred in two of 13 such transmissions: the changes observed were
limited to only one or two repeats. Premutation FRAXA alleles over 100
repeats expanded to a full mutation during female transmission in 100% of
cases, in agreement with other published series. There was no clear
correlation between haplotype and probability of expansion of FRAXA
premutations. Instability at FRAXA or FRAXE was more often observed in
conjunction with a second instability at an independent locus suggesting
genomic instability as a possible mechanism by which at least some FRAXA
and FRAXE mutations arise.
相似文献
65.
Recent case control studies suggest that breast self-examination (BSE) is efficacious in the early clinical diagnosis of breast cancer. Population studies also indicate that adoption of this behavior depends largely on physicians. This pilot study was designed to determine whether physicians' attitudes on this subject could be obtained through a mail questionnaire. The results show that a self-administered mail questionnaire can be used successfully in physician studies. Although questionnaire length does affect response rates (78% one page, 69% four page, and 57% eight page), it does not affect either respondent characteristics or question response. 相似文献
66.
67.
M G Marin J Van Lieu A Yee E Bonner S Glied 《Journal of occupational and environmental medicine / American College of Occupational and Environmental Medicine》1999,41(9):754-760
We performed a cost-effectiveness analysis of a post-exposure chemoprophylaxis program for health care workers who sustained exposures to blood. We analyzed a program of (1) treatment with zidovudine alone versus no treatment and (2) treatment with three-drug therapy versus no treatment. Assuming that 35% of exposures were to HIV-positive sources, the zidovudine regimen prevented 53 HIV seroconversions per 100,000 exposures, at a societal cost of $2.0 million per case of HIV prevented. The cost per quality-adjusted life year saved was $175,222. A three-drug chemoprophylactic therapy program (postulating 100% effectiveness and 35% source HIV positivity), prevented 66 seroconversions per 100,000 exposures, at a cost of $2.1 million per case of HIV prevented and $190,392 per quality-adjusted life year saved. Treating sources known to be HIV-positive and treating severe exposures were the most cost-effective strategies. 相似文献
68.
The clinical application of endovascular grafts began with the work of Parodi in 1990, which fused intravascular stent and prosthetic graft technologies. These less invasive devices have been applied to the treatment of arterial aneurysm, long segment occlusive disease, and traumatic vascular injuries. A host of different systems have been developed that exploit the unique properties of balloon, superelastic metal, and vascular graft devices. 相似文献
69.
Traumatic spinal cord injury is a devastating condition that alters every aspect of the victim's life. Motor vehicle accidents cause about half of the cases, whereas others are the result of falls, recreational and sporting accidents, or acts of violence. We report a case of a C3 spinal fracture with a resultant Brown Sequard syndrome, which occurred in a unique manner and could have easily been prevented. There is a need for the medical community to play a more active role in educating the public to prevent accidents that lead to these catastrophic injuries. 相似文献