全文获取类型
收费全文 | 2674篇 |
免费 | 180篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 254篇 |
妇产科学 | 80篇 |
基础医学 | 323篇 |
口腔科学 | 63篇 |
临床医学 | 291篇 |
内科学 | 501篇 |
皮肤病学 | 36篇 |
神经病学 | 141篇 |
特种医学 | 493篇 |
外科学 | 174篇 |
综合类 | 43篇 |
预防医学 | 128篇 |
眼科学 | 56篇 |
药学 | 140篇 |
中国医学 | 3篇 |
肿瘤学 | 149篇 |
出版年
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 18篇 |
2018年 | 23篇 |
2017年 | 22篇 |
2016年 | 34篇 |
2015年 | 41篇 |
2014年 | 47篇 |
2013年 | 77篇 |
2012年 | 73篇 |
2011年 | 65篇 |
2010年 | 91篇 |
2009年 | 70篇 |
2008年 | 60篇 |
2007年 | 75篇 |
2006年 | 71篇 |
2005年 | 73篇 |
2004年 | 66篇 |
2003年 | 52篇 |
2002年 | 47篇 |
2001年 | 45篇 |
2000年 | 64篇 |
1999年 | 57篇 |
1998年 | 153篇 |
1997年 | 141篇 |
1996年 | 143篇 |
1995年 | 101篇 |
1994年 | 92篇 |
1993年 | 101篇 |
1992年 | 61篇 |
1991年 | 50篇 |
1990年 | 48篇 |
1989年 | 81篇 |
1988年 | 70篇 |
1987年 | 79篇 |
1986年 | 69篇 |
1985年 | 67篇 |
1984年 | 38篇 |
1983年 | 45篇 |
1982年 | 42篇 |
1981年 | 27篇 |
1980年 | 44篇 |
1979年 | 29篇 |
1978年 | 25篇 |
1977年 | 28篇 |
1976年 | 31篇 |
1975年 | 33篇 |
1974年 | 10篇 |
1973年 | 14篇 |
1971年 | 11篇 |
排序方式: 共有2877条查询结果,搜索用时 0 毫秒
31.
Huisman JA; Paulussen RJ; Geurts TB; Odink J; Rekers H 《Human reproduction (Oxford, England)》1997,12(1):34-38
The objective was to demonstrate bioequivalence between s.c. and i.m.
administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio
3:1). In two randomized, single-centre, cross-over studies, 18 healthy
volunteers on each formulation were assigned to one of the two
administration sequences. Subjects were given single doses of one of the
above gonadotrophins after endogenous gonadotrophin production had first
been suppressed using high-dose oral contraceptive. Subsequently, rate
(Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone
(FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax
and AUC, analysis of variance (ANOVA) was performed on log-transformed data
and for tmax ANOVA was performed on ranks. Intramuscular and s.c.
injections of Humegon were bioequivalent with respect to the main
pharmacokinetic parameters, being AUC and Cmax of FSH absorption.
Intramuscular and s.c. injections of Normegon were bioequivalent with
respect to the AUC of FSH and not bioequivalent with respect to the Cmax of
FSH. For tmax of FSH as well as for most LH variables of both preparations,
bioequivalence could not be proven due to the high intra- and
interindividual variability and/or concentrations being close to the
detection limit. Thus, the main pharmacokinetic FSH variables after i.m.
and s.c. administration of Humegon and Normegon were bioequivalent.
相似文献
32.
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
33.
34.
Reduced hippocampal insulin-degrading enzyme in late-onset Alzheimer's disease is associated with the apolipoprotein E-epsilon4 allele 总被引:5,自引:0,他引:5 下载免费PDF全文
Cook DG Leverenz JB McMillan PJ Kulstad JJ Ericksen S Roth RA Schellenberg GD Jin LW Kovacina KS Craft S 《The American journal of pathology》2003,162(1):313-319
Abeta is the major component of amyloid plaques characterizing Alzheimer's disease (AD). Abeta accumulation can be affected by numerous factors including increased rates of production and/or impaired clearance. Insulin-degrading enzyme (IDE) has been implicated as a candidate enzyme responsible for the degradation and clearance of Abeta in the brain. We have previously shown that AD patients exhibit abnormalities in insulin metabolism that are associated with apoliprotein E (APOE) status. The possible association of IDE with AD, as well as the link between APOE status and insulin metabolism, led us to examine the expression of IDE in AD. We report that hippocampal IDE protein is reduced by approximately 50% in epsilon4+ AD patients compared to epsilon4- patients and controls. The allele-specific decrease of IDE in epsilon4+ AD patients is not associated with neuronal loss since neuron-specific enolase levels were comparable between the AD groups, regardless of APOE status. Hippocampal IDE mRNA levels were also reduced in AD patients with the epsilon4 allele compared to AD and normal subjects without the epsilon4 allele. These findings show that reduced IDE expression is associated with a significant risk factor for AD and suggest that IDE may interact with APOE status to affect Abeta metabolism. 相似文献
35.
KM Kanal NJ Hangiandreou AM Sykes HE Eklund PA Araoz JA Leon BJ Erickson 《Journal of digital imaging》2002,14(1):30-37
The aims of this work were to measure the accuracy of one continuous speech recognition product and dependence on the speaker's
gender and status as a native or nonnative English speaker, and evaluate the product's potential for routine use in transcribing
radiology reports. IBM MedSpeak/Radiology software, version 1.1 was evaluated by 6 speakers. Two were nonnative English speakers,
and 3 were men. Each speaker dictated a set of 12 reports. The reports included neurologic and body imaging examinations performed
with 6 different modalities. The dictated and original report texts were compared, and error rates for overall, significant,
and subtle significant errors were computed. Error rate dependence on modality, native English speaker status, and gender
were evaluated by performing ttests. The overall error rate was 10.3 +/- 3.3%. No difference in accuracy between men and women
was found; however, significant differences were seen for overall and significant errors when comparing native and nonnative
English speakers (P = .009 and P = .008, respectively). The speech recognition software is approximately 90% accurate, and
while practical implementation issues (rather than accuracy) currently limit routine use of this product throughout a radiology
practice, application in niche areas such as the emergency room currently is being pursued. This methodology provides a convenient
way to compare the initial accuracy of different speech recognition products, and changes in accuracy over time, in a detailed
and sensitive manner. 相似文献
36.
Lesions of the articular surfaces of the knee have been managed by various techniques over the last 50 years. Surgical management has involved: excising the damaged area, refashioning the underlying bone to produce a fibrous response, and introducing allograft, autograft and synthetic materials to encourage a repair matrix. The techniques and their pitfalls are reviewed and discussed, and suggestions made as to the direction of future studies for the repair of osteochondral lesions in the painful knee. 相似文献
37.
Immunological factors in endometriosis-associated reproductive failure: studies in fertile and infertile women with and without endometriosis 总被引:7,自引:4,他引:7
Martinez-Roman S; Balasch J; Creus M; Fabregues F; Carmona F; Vilella R; Vanrell JA 《Human reproduction (Oxford, England)》1997,12(8):1794-1799
Immunopathophysiological mechanisms in endometriosis-associated
reproductive failure were studied in appropriate populations: infertile and
fertile women with and without endometriosis. The incidence of sera
positive for any of the autoantibodies tested among infertile women with
endometriosis (n = 25) was similar to that observed in the three control
groups [unexplained infertility patients (n = 25) and fertile women with (n
= 10) and without (n = 25) endometriosis]. The mean volume of peritoneal
fluid was significantly elevated in women with endometriosis (both fertile
and infertile) as compared with patients without endometriosis (fertile or
infertile). The concentration of peritoneal fluid leukocytes and the
percentage of cells positive for macrophage markers were significantly
increased and the percentage of T lymphocytes significantly decreased in
infertile women with endometriosis but not in patients with unexplained
infertility and fertile women with endometriosis, as compared with fertile
controls without endometriosis. Macrophages from infertile patients with
endometriosis had higher sperm phagocytosis than did those from infertile
women without endometriosis or fertile subjects with or without
endometriosis. Incidences of serum and peritoneal fluid samples embryotoxic
to the in-vitro development of 2-cell mouse embryos were significantly
higher in infertile patients with endometriosis than in unexplained
infertility patients and fertile women with or without endometriosis. It is
concluded that immunological mechanisms of endometriosis-associated
infertility exist but that these peritoneal immunological factors in
infertile women with endometriosis are related to their subfertility rather
than to the presence of ectopic endometrial implants. This is supported by
the lack of immunological abnormalities observed among fertile women with
endometriosis. These immunological abnormalities are lacking in patients
with unexplained infertility.
相似文献
38.
The ileoanal J pouch: radiographic evaluation 总被引:1,自引:0,他引:1
Endorectal ileoanal pull-through offers an attractive alternative to proctocolectomy and ileostomy for patients with ulcerative colitis, Gardner syndrome, and familial polyposis. To our knowledge, a careful radiographic analysis of the ileum, ileal pouch, and ileoanal anastomosis after ileoanal pull-through has not been reported. Thirty-two patients with ulcerative colitis, Gardner syndrome, and familial polyposis underwent colectomy, mucosal proctectomy, and endorectal ileoanal pull-through of a 15-cm ileal "J" pouch and loop ileostomy. Twenty-five (78%) of 32 of all the pouches radiographically demonstrated spiral folds extending from the middle of the pouch to the pectinate line. Other radiographic features included a mesenteric mass effect, pseudopolyps, and a central lucency that indicated intrapouch sutures. Radiographs provide useful information in the postoperative management of the ileal pull-through. 相似文献
39.
Cortina Chandler S. Bergom Carmen Craft Morgan Ashley Fields British Brazauskas Ruta Currey Adam Kong Amanda L. 《Annals of surgical oncology》2021,28(10):5568-5579
Annals of Surgical Oncology - Management of axillary lymph nodes in breast cancer has undergone significant change over the past decade through landmark clinical trials. This study aimed to assess... 相似文献
40.