全文获取类型
收费全文 | 628篇 |
免费 | 40篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 32篇 |
妇产科学 | 10篇 |
基础医学 | 83篇 |
口腔科学 | 23篇 |
临床医学 | 53篇 |
内科学 | 101篇 |
皮肤病学 | 21篇 |
神经病学 | 16篇 |
特种医学 | 139篇 |
外科学 | 75篇 |
综合类 | 22篇 |
预防医学 | 27篇 |
眼科学 | 7篇 |
药学 | 30篇 |
肿瘤学 | 40篇 |
出版年
2024年 | 2篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 10篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 22篇 |
2014年 | 15篇 |
2013年 | 13篇 |
2012年 | 13篇 |
2011年 | 28篇 |
2010年 | 30篇 |
2009年 | 36篇 |
2008年 | 17篇 |
2007年 | 30篇 |
2006年 | 25篇 |
2005年 | 28篇 |
2004年 | 35篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 22篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 21篇 |
1997年 | 38篇 |
1996年 | 24篇 |
1995年 | 22篇 |
1994年 | 17篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 15篇 |
1986年 | 9篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 1篇 |
排序方式: 共有681条查询结果,搜索用时 15 毫秒
671.
Embryo morphology or cleavage stage: how to select the best embryos for transfer after in-vitro fertilization 总被引:11,自引:15,他引:11
Ziebe S; Petersen K; Lindenberg S; Andersen AG; Gabrielsen A; Andersen AN 《Human reproduction (Oxford, England)》1997,12(7):1545-1549
This retrospective study of 1001 in-vitro fertilization (IVF) cycles
included a consecutive series of single transfers (n = 341), dual transfers
(n = 410) and triple transfers (n = 250) where all the transferred embryos
in each cycle were of identical quality score and identical cleavage stage.
In our 2 day culture system, transfer of 4- cell embryos resulted in a
significantly higher implantation rate and pregnancy rate (23 and 49%)
compared with 2-cell embryos (12 and 22%) and 3-cell embryos (7 and 15%).
Furthermore, the transfer of 4-cell embryos resulted in a significantly
higher pregnancy rate compared with embryos that had cleaved beyond the
4-cell stage (28%). The implantation rate (21%) and pregnancy rate (43%)
after transfer of embryos of score 1.0 were significantly higher than after
transfer of embryos of score 2.0 (14 and 32% respectively). Transferring
embryos of score 2.1 resulted in significantly higher implantation rates
(26%) and similar pregnancy rates compared with score 1.0. Transferring
embryos of score 2.2-3.0 resulted in a significantly lower implantation
rate (5%) and pregnancy rate (15%). A striking finding was that embryos of
quality score 2.0 had a significantly lower implantation rate compared with
embryos of quality score 1.0 and 2.1 and a significantly lower pregnancy
rate compared to embryos of quality score 1.0. We also found a lower
implantation rate and pregnancy rate when transferring 3-cell embryos.
These findings may indicate periods of increased sensitivity to damage
during the cell cycle. In conclusion, these results substantiate the idea
of the superiority of 4-cell embryos and demonstrate that minor amounts of
fragments in the embryo may not be of any importance. These findings may
call for a shift when weighing the two main morphological components
(quality score and cleavage stage) in the sense that reaching a 4-cell
cleavage stage even with the presence of a minor amount of fragments should
be preferred to a 2-cell embryo with no fragments.
相似文献
672.
Fukuda M; Fukuda K; Andersen CY; Byskov AG 《Human reproduction (Oxford, England)》1998,13(6):1590-1594
The present study was undertaken to evaluate whether the site of ovulation
affects the following follicular phase length and pre-embryo development
during infertility treatment with ovarian stimulation using clomiphene
citrate. A total of 363 cycles in 97 patients undergoing infertility
treatment (182 intrauterine insemination (IUI) cycles in 60 patients and
181 in-vitro fertilization (IVF) cycles in 52 patients) were studied. The
cycles were divided into two main groups: preceding unilateral ovulation
(PUO) and preceding bilateral ovulation (PBO). In the PUO group, the cycles
were subdivided into contralateral ovulation, bilateral ovulation and
ipsilateral ovulation. In IVF cycles alone, bilateral ovulations were
further divided into bilateral ovulation- contralateral side and bilateral
ovulation, ipsilateral side. Contralateral ovulations were seen in 134 of
240 cycles (56%), excluding bilateral ovulation and PBO. The follicular
phase length in contralateral ovulation (16.2 +/- 2.6 days, mean +/- SD)
was significantly (P < 0.05) shorter than that of ipsilateral ovulation
(16.9 +/- 2.8). There were no significant differences of follicular phase
length among contralateral ovulation, bilateral ovulation and PBO. Of IVF
cycles including contralateral ovulation-ipsilateral ovulation and
bilateral ovulation a total of 107 preovulatory follicles was assessed in
the contralateral side (contralateral ovulation + bilateral
ovulation-contralateral side) and 97 in the ipsilateral side (ipsilateral
ovulation + bilateral ovulation, ipsilateral side). The oocyte retrieval
rate (88%), fertilization rate (84%), cleavage rate (95%), embryo transfer
rate (70%) of contralateral follicles were higher than those of ipsilateral
follicles (71, 62, 86, 38% respectively) and those of PBO (76, 62, 87, 41%
respectively). The total pregnancy rate of both IUI and IVF did not differ
among contralateral ovulation (15%), ipsilateral ovulation (8%), bilateral
ovulation (11%) and PBO (10%). The results confirm and extend our previous
findings in natural cycles, suggesting that local ovarian factors, e.g.
from corpus luteum, affect the health of preovulatory follicle and the
enclosed oocyte in the same ovary (ipsilateral) negatively. Contralateral
selection of preovulatory follicles in the succeeding cycle shortens the
follicular phase length and favours pre- embryo development. The chance of
conceiving during ovarian stimulation with clomiphene citrate may thus be
affected by the site of ovulation in the previous cycle.
相似文献
673.
674.
Laina Knorr Julie D Fox Peter AG Tilley Jasmine Ahmed-Bentley 《BMC infectious diseases》2006,6(1):62-12
Background
Nucleic acid amplification of the IS481 region by PCR is more sensitive than culture for detection and diagnosis of Bordetella pertussis but the assay has known cross-reactivity for Bordetella holmesii and its use as a routine diagnostic assay has not been widely evaluated. 相似文献675.
676.
RP Jones NA Stylianides AG Robertson VSK Yip G Chadwick 《Annals of the Royal College of Surgeons of England》2015,97(5):386-389
IntroductionGastrointestinal (GI) endoscopy is an important skill for both gastroenterologists and general surgeons but concerns have been raised about the provision and delivery of training. This survey aimed to evaluate and compare the delivery of endoscopy training to gastroenterology and surgical trainees in the UK.MethodsA nationwide electronic survey was carried out of UK gastroenterology and general surgery trainees.ResultsThere were 216 responses (33% gastroenterologists, 67% surgeons). Gastroenterology trainees attended more non-training endoscopy lists (mean: 3.0 vs 1.2) and training lists than surgical trainees (mean: 0.9 vs 0.5). A significantly higher proportion of gastroenterologists had already achieved accreditation in gastroscopy (60.8% vs 28.9%), colonoscopy (66.7% vs 1.4%) and flexible sigmoidoscopy (33.3% vs 3.0%). More gastroenterology trainees aspired to achieve accreditation in gastroscopy (97.2% vs 79.2%), flexible sigmoidoscopy (91.7% vs 70.1%) and colonoscopy (88.8% vs 55.5%) by completion of training. By completion of training, surgeons were less likely than gastroenterologists to have completed the required number of procedures to gain accreditation in gastroscopy (60.3% vs 91.3%), flexible sigmoidoscopy (64.6% vs 68.6%) and colonoscopy (60.3% vs 70.3%).ConclusionsThis survey highlights marked disparities between surgical and gastroenterology trainees in both aiming for and achieving accreditation in endoscopy. Without changes to the delivery and provision of training as well as clarification of the role of endoscopy training in a surgical training programme, future surgeons will not be able to perform essential endoscopic assessment of patients as part of their management algorithm. 相似文献
677.
Nanna?von der LippeEmail author B?rd?Waldum Fredrik?B?Brekke Amin?AG?Amro Anna?Varberg?Reis?ter Ingrid?Os 《BMC nephrology》2014,15(1):191
Background
Little is known how health related quality of life (HRQOL) change in the transition from dialysis to renal transplantation (RTX). Longitudinal data addressing the patient-related outcomes are scarce, and particularly data regarding kidney-specific HRQOL are lacking. Thus, the aim of the current study was to assess HRQOL in patients followed from dialysis to RTX. Furthermore, to compare HRQOL in RTX patients and the general population.Methods
In a prospective study, HRQOL was measured in a cohort of 110 patients (median age 53.5 (IQR 39–62) years, GFR 54 (45–72) ml/min/1.73 m2) in dialysis and after RTX using the self-administered Kidney Disease and Quality of Life Short Form version 1.3 (KDQOL-SF). Generic HRQOL in the RTX patients was compared to that of the general population (n?=?5903) using the SF-36. Clinical important change after RTX was defined as difference in HRQOL of SD/2.Results
Follow-up time was 55 (IQR 50–59) months, and time after RTX was 41 (34–51) months. Four of nine domains in kidney-specific HRQOL improved after RTX, i.e. burden of kidney disease, effect of kidney disease, symptoms and work status. In SF-36, general health, vitality, social function and role physical improved after RTX, but none of the domains improved sufficiently to be regarded as clinically relevant change. There were highly significant differences in HRQOL between RTX patients and the general population after adjustment for age and gender for all items of SF-36 except for bodily pain and mental health.Conclusions
HRQOL improved in the transition from dialysis to transplantation, but clinical relevant change was only obtained in the kidney specific domains. HRQOL was perceived considerably poorer in RTX patients than in the general population. Our observations point to the need of improving HRQOL even after RTX, and should encourage further longitudinal research and clinical attention during treatment shift.678.
679.
Interleukin-3 and interleukin-7 are alternative growth factors for the same B-cell precursors in the mouse 总被引:3,自引:0,他引:3
Clones and lines of precursor (pre) B cells can be established by limiting dilutions of unseparated cell suspensions of fetal liver or bone marrow on stromal cells in the presence of interleukin (IL)-7. When IL-3 is used instead of IL-7, cultures are regularly overgrown by different precursor cells of the myeloid lineage, as well as by adherent cells that inhibit pre-B-cell expansion. However, in the presence of either IL-7 or IL-3, clones of pre-B cells can be established on stroma cells at frequencies near one in one when the cultures are initiated with cell sorter purified CD45RO (B220)+/c-kit+ fetal liver or bone marrow derived pre-B cells. Clones grown on stromal cells in the presence of IL-7 can be regrown in IL-3, and vice versa. Pre-B cells that proliferate on stromal cells in the presence of IL-7 or IL-3 have the same phenotype, ie, are B220+ c-kit+, CD43+, and surrogate light chain+. Removal of the growth factors (IL-7, respectively IL-3) from the cultures results in differentiation to surface immunoglobulin (slg) positive, c-kit-, CD43-, surrogate light chain- B cells, a fraction of which is lipopolysaccharide (LPS) responsive as shown by IgM secretion. These results show that IL-7 and IL-3 stimulate largely overlapping populations of precursor B cells from bone marrow to proliferate for long periods of time in the presence of stromal cells. Thus, IL-7 and IL-3 are alternative growth factors for the same pre-BI cell. 相似文献
680.