全文获取类型
收费全文 | 714篇 |
免费 | 79篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 66篇 |
妇产科学 | 6篇 |
基础医学 | 94篇 |
口腔科学 | 30篇 |
临床医学 | 74篇 |
内科学 | 144篇 |
皮肤病学 | 19篇 |
神经病学 | 23篇 |
特种医学 | 128篇 |
外科学 | 43篇 |
综合类 | 42篇 |
预防医学 | 25篇 |
眼科学 | 29篇 |
药学 | 13篇 |
肿瘤学 | 62篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 21篇 |
2017年 | 7篇 |
2016年 | 21篇 |
2015年 | 24篇 |
2014年 | 26篇 |
2013年 | 41篇 |
2012年 | 19篇 |
2011年 | 14篇 |
2010年 | 44篇 |
2009年 | 44篇 |
2008年 | 16篇 |
2007年 | 26篇 |
2006年 | 12篇 |
2005年 | 17篇 |
2004年 | 10篇 |
2003年 | 14篇 |
2002年 | 9篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 40篇 |
1997年 | 43篇 |
1996年 | 44篇 |
1995年 | 37篇 |
1994年 | 22篇 |
1993年 | 28篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 20篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 5篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 2篇 |
1884年 | 1篇 |
排序方式: 共有801条查询结果,搜索用时 15 毫秒
91.
92.
93.
Jansen PM; Pixley RA; Brouwer M; de Jong IW; Chang AC; Hack CE; Taylor FB Jr; Colman RW 《Blood》1996,87(6):2337-2344
In previous studies, we have shown that administration of monoclonal antibody (MoAb) C6B7 against human factor XII to baboons challenged with a lethal dose of Escherichia coli abrogates activation of the contact system and modulates secondary hypotension. To evaluate the contribution of activated contact proteases to the appearance of other inflammatory mediators in this experimental model of sepsis, we studied the effect of administration of MoAb C6B7 on activation of complement and fibrinolytic cascades, stimulation of neutrophil degranulation, and release of the proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Activation of the complement system, as reflected by circulating C3b/c and C4b/c levels, was significantly reduced in five animals that had received MoAb C6B7 before a lethal dose of E coli as compared with five control animals that had been given a lethal challenge only. Inhibition of contact activation also modulated the fibrinolytic response, since the release of tissue-type plasminogen activator (t-PA) and the appearance of plasmin-alpha2-antiplasmin (PAP) complexes into the circulation was significantly attenuated upon pretreatment with anti-factor XII MoAb. In contrast, plasma levels of plasminogen activator inhibitor (PAI) were modestly enhanced in the treatment group. Degranulation of neutrophils, as assessed by circulating elastase-alpha1-protease inhibitor complexes, and release of IL-6 but not of TNF-alpha was decreased in anti-factor XII-treated animals. Observed differences in the inflammatory response between treatment and control groups were not likely due to different challenges, since the number of E coli that had been infused, as well as circulating levels of endotoxin after the challenge, were similar for both groups. These data suggest that activation of the contact system modulates directly or indirectly various mediator systems involved in the inflammatory response during severe sepsis in nonhuman primates. 相似文献
94.
Pecorara M; Casarino L; Mori PG; Morfini M; Mancuso G; Scrivano AM; Boeri E; Molinari AC; De Biasi R; Ciavarella N 《Blood》1987,70(2):531-535
In this study, we used DNA polymorphisms for carrier detection and prenatal diagnosis of hemophilia A in a large group of Italian families. The restriction fragment length polymorphisms (RFLPs) investigated were the intragenic polymorphic Bc/I site within the factor VIII gene; the extragenic multiallelic Taq I system at the St14 locus; and the extragenic Bg/II site at the DX13 locus. The factor VIII probe was informative in 30%, St14 in 82%, and DX13 in 60% of obligate carriers. The combination of factor VIII-Bc/I and St14-Taq I showed that 91% of obligate carriers were heterozygotes for one or both; with all three probes, only 4% of obligate carriers were noninformative. In families clearly segregating for hemophilia A, RFLP analysis allowed us to define the carrier status for the hemophilia A gene in all 27 women tested. RFLP analysis allowed us to exclude the carrier status in 39 of 45 female relatives of sporadic patients. The combination of RFLP analysis and biological assay of factor VIII allowed us to identify a de novo mutation in the maternal grandfather in 7 of 12 of the families with sporadic cases, for which members of three generations were available for study. Nine of 10 couples requesting prenatal diagnosis provided informative RFLP DNA pattern. Carrier status was excluded in two women, two fetuses were shown to be female, and prenatal diagnosis was carried out in five pregnancies by DNA analysis. Prenatal testing was successful in three instances and failed in two because a sufficient amount of chorionic villous DNA was not obtained for the analysis. 相似文献
95.
Nonhomogeneous distribution of leukemia in the bone marrow during minimal residual disease 总被引:2,自引:0,他引:2
In a rat model (BNML) for human acute myelocytic leukemia the distribution of leukemic cells in bone marrow samples from various sites was investigated, using monoclonal antibodies (MoAbs) and flow cytometry. Rats were studied before chemotherapy as well as thereafter, ie, in the "minimal residual disease" (MRD) phase. Bone marrow from different types of bones was analyzed from each animal. Before treatment, the ratio of the measured extreme values (ie, highest/lowest value) for leukemic cell frequencies in bones from individual rats ranged from 3.7 to 11.7. During the MRD phase the ratios of the extremes ranged from a factor of 36 to more than 13,000 from one rat to another. The variability between bones of comparable size was estimated by studying the ribs from each individual animal. Within individuals the extremes differed by a factor of 1.2 to 4.0 before chemotherapy and from 2.4 to greater than 320 after chemotherapy. The variability within the marrow cavity of a single bone was determined by analyzing multiple samples from femoral bones cut into slices. The leukemic cell frequency appeared to vary considerably, ie, before treatment from 1.7 to 7.3 and during MRD from 4 to 28,000. The presented data may contribute to understanding the sometimes conflicting observations in leukemic patients. Improvement of methods for detecting MRD will not automatically lead to a more accurate estimation of the total tumor burden. The reliability of diagnoses based on the analysis of single bone marrow aspirates appears to be highly questionable. 相似文献
96.
RG Lee K Nakamura AC Tsamandas K Abu-Elmagd H Furukawa WR Hutson J Reyes JS Tabasco-Minguillan S Todo AJ Demetris 《Gastroenterology》1996,110(6):1820-1834
BACKGROUND & AIMS: Intestinal transplantation is a developing therapeutic option for patients with irreversible intestinal failure or short bowel syndrome. The aim of this study was to delineate the histopathology of human intestinal allografts and to define the features of intestinal rejection. METHODS: The histological features of 3015 endoscopic biopsy specimens and 23 allograft specimens from 62 intestinal recipients were analyzed retrospectively and correlated with clinical findings. RESULTS: Acute allograft rejection was characterized by a varying combination of crypt injury, mucosal infiltration primarily by mononuclear cells (including blastic lymphocytes), and increased crypt cell apoptosis (more than 2 per 10 crypts). It represented a patchy, often ileal-centered process that could progress to mucosal ulceration; later episodes (more than 100 days posttransplant) tended to show lesser cellular infiltration and greater apoptosis than earlier episodes. Correlation with clinical rejection was good (false-positive rate of 9%; false-negative rate of 26%). Two resected specimens showed obliterative arteriopathy indicative of chronic rejection. In other specimens, preservation injury, cytomegalovirus infection, post-transplant lymphoproliferative disorder, and nonspecific features of active or past mucosal injury could be recognized. CONCLUSIONS: Mucosal biopsy specimens are a useful means of monitoring intestinal allografts. Based on features validated by clinical correlation, acute rejection can be identified reliably and can be differentiated from the other pathological processes affecting the intestinal allograft. (Gastroenterology 1996 Jun;110(6):1820-34) 相似文献
97.
AC Chambers AV Patil R Alves JC Hopkins J Armstrong RN Lawrence 《Annals of the Royal College of Surgeons of England》2012,94(8):548-551
INTRODUCTION
Vernix caseosa peritonitis (VCP) is a rare and poorly recognised condition resulting from a sustained foreign body reaction to the vernix caseosa of the baby. This case-based review aims to highlight its importance for any medical team managing patients with peritonitis who have undergone a recent Caesarean section.CASE REPORT
A 31-year-old woman presented 5 weeks after a Caesarean section with symptoms and signs of peritonitis.CONCLUSIONS
Laparotomy and peritoneal lavage is the mainstay of treatment for VCP. Knowledge of the condition may stop inadvertent resection of normal intra-abdominal organs. Greater awareness of VCP is required to ensure earlier recognition as patients can recover well following timely operative intervention. 相似文献98.
99.
Selective transfer of cryopreserved human embryos with further cleavage after thawing increases delivery and implantation rates 总被引:6,自引:10,他引:6
Van der Elst J; Van den Abbeel E; Vitrier S; Camus M; Devroey P; Van Steirteghem AC 《Human reproduction (Oxford, England)》1997,12(7):1513-1521
We investigated whether further in-vitro culture of human multicellular
embryos that survive cryopreservation can select the viable embryos for
transfer. Embryos for cryopreservation were supernumerary multicellular
embryos obtained after in-vitro fertilization (IVF) and intracytoplasmic
sperm injection (ICSI) treatments, with <20% of their volume filled with
anucleate fragments. These had been cryopreserved using a slow-freezing and
slow-thawing protocol with 1.5 M dimethylsulphoxide as the cryoprotectant.
From the start of our cryopreservation programme until September 12, 1994,
the thawing strategy was to thaw frozen embryos up to the exact number
needed for transfer. Embryos for transfer were selected on the basis of
their morphological appearance and embryo transfer to the patient was done
on the day of thawing. From September 12, 1994 onwards we used a more
selective thawing strategy where a cohort of up to a maximum of 12 frozen
embryos per patient is thawed from which embryos of the best morphological
quality, and which are furthest advanced in terms of cleavage after a 24 h
in-vitro culture period in Menezo B2 medium, are selected. We took delivery
rates, embryo implantation rates and birth rates into account to see if
there is any difference between the following three types of transfers
used: 187 transfers exclusively of embryos having continued to cleave after
thawing, 107 mixed transfers of embryos with and without further cleavage
and 53 transfers exclusively of embryos with no further cleavage. The
overall outcome in terms of delivery rate and embryo implantation and birth
rates were not different between the new and the earlier thawing policies
(6.6, 5.2 and 3.6% versus 6.0, 4.1 and 2.7% respectively). Only when a
distinction was made between transfers on the basis of the presence of
embryos with further cleavage, did the advantage of selection on the basis
of cleavage capacity become evident. Significantly higher delivery and
embryo implantation and birth rates (11.2, 7.7 and 6.5% respectively) were
recorded with transfers exclusively of embryos with further cleavage versus
mixed transfers of embryos with and without further cleavage (1.9, 2.9 and
0.6% respectively). Fifty-three transfers exclusively of embryos with no
further cleavage did not lead to any delivery. Our results demonstrate that
selection of human multicellular embryos which survive cryopreservation and
continue to cleave in vitro can significantly improve the delivery rate per
transfer and the implantation rate per transferred embryo.
相似文献
100.