首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1035篇
  免费   71篇
  国内免费   35篇
耳鼻咽喉   3篇
儿科学   27篇
妇产科学   8篇
基础医学   99篇
口腔科学   22篇
临床医学   94篇
内科学   234篇
皮肤病学   13篇
神经病学   34篇
特种医学   128篇
外科学   125篇
综合类   89篇
预防医学   81篇
眼科学   30篇
药学   111篇
肿瘤学   43篇
  2022年   8篇
  2021年   18篇
  2020年   7篇
  2019年   16篇
  2018年   27篇
  2017年   22篇
  2016年   24篇
  2015年   20篇
  2014年   28篇
  2013年   52篇
  2012年   53篇
  2011年   59篇
  2010年   26篇
  2009年   41篇
  2008年   47篇
  2007年   67篇
  2006年   54篇
  2005年   45篇
  2004年   37篇
  2003年   27篇
  2002年   25篇
  2001年   20篇
  2000年   19篇
  1999年   25篇
  1998年   39篇
  1997年   25篇
  1996年   25篇
  1995年   21篇
  1994年   19篇
  1993年   17篇
  1992年   9篇
  1991年   20篇
  1990年   8篇
  1989年   20篇
  1988年   21篇
  1987年   16篇
  1986年   13篇
  1985年   8篇
  1984年   10篇
  1983年   14篇
  1982年   9篇
  1981年   12篇
  1980年   11篇
  1979年   4篇
  1978年   9篇
  1977年   5篇
  1975年   13篇
  1974年   9篇
  1973年   4篇
  1972年   4篇
排序方式: 共有1141条查询结果,搜索用时 15 毫秒
101.
Dipeptide-derived compounds, bearing various P2 residues and a diaryl pyrrolidin-2-yl phosphonate at the P1 position, were evaluated as dipeptidyl peptidase 8 (DPP8) inhibitors. With these products, irreversible inhibition of DPP8 was observed. To obtain inhibitors with an improved activity and selectivity profile, a set of selected analogues containing a diaryl isoindolin-1-ylphosphonate at P1 was synthesized and evaluated. Within this latter series, compound 2e was shown to be a potent, irreversible inhibitor of DPP8, demonstrating very low affinity for DPP IV and DPP II.  相似文献   
102.
103.
Wood  GS; Garcia  CF; Dorfman  RF; Warnke  RA 《Blood》1985,66(5):1092-1097
Follicle lysis is a characteristic alteration of B cell follicles described recently in lymph node biopsies from homosexual men. It consists of disruption of germinal centers by aggregates of small mature lymphocytes variably associated with erythrocyte extravasation. We studied the immunohistology of follicle lysis identified in lymph node biopsies from 11 homosexual men. The results indicate that follicle lysis has two principal immunohistologic features: (1) intrafollicular aggregates of small lymphocytes predominantly of polytypic mantle B cell phenotype (T015+/Leu-8+/mu+/delta+/k+ or lambda+), and (2) disruption of the normal, unified follicular meshwork of R4/23+ dendritic reticulum cells by these B cell aggregates. These structural alterations may affect the functional integrity of the germinal center as it pertains to the abnormal B cell effector function and the increased prevalence of B cell lymphoma recently documented in the acquired immunodeficiency syndrome and related disorders. Because dendritic reticulum cells weakly express the Leu-3 (T4) antigen, which is known to be an essential component of the receptor for human T- lymphotropic virus type III/lymphadenopathy-associated virus (HTLV- III/LAV) retrovirus infection, it is possible that retroviral infection of dendritic reticulum cells may play a role in the pathogenesis of follicle lysis.  相似文献   
104.
105.

Background

The aim of this study was to assess the role of middle cerebral artery peak systolic velocity (MCA-PSV), as measured by doppler ultrasound, in detecting foetal anaemia in Rh- isoimmunised pregnancies. Intra-uterine foetal blood transfusion was performed in such anaemic foetuses to tide over the crisis of foetal immaturity till considered fit for extra-uterine survival.

Methods

Rh-isoimmunised pregnancies reporting to a tertiary institute from 2003 to 2005, were screened by doppler ultrasound to estimate MCA-PSV to detect foetal anaemia. If the foetus developed MCA-PSV of more than 1.5 multiple of median (MoM) for the gestational age, foetal blood sampling through cordocentesis was performed to confirm foetal anaemia, followed by intrauterine foetal blood transfusion to all anaemic foetuses at the same sitting. Neonatal outcome was evaluated by recording gestational age at the time of delivery, duration of gestational time gained and need for blood transfusion in the neonatal period.

Results

A total of thirteen isoimmunised pregnancies were evaluated. Three pregnancies did not require in-utero foetal blood transfusion. Twenty-one intrauterine foetal blood transfusions were performed in the remaining ten patients. Five received blood transfusion in the neonatal period. Intra uterine foetal death occurred in one grossly hydropic foetus and favourable neonatal outcome was recorded in the rest.

Conclusion

The clinical outcome of these pregnancies justifies the use of doppler studies of MCA-PSV in detecting foetal anaemia and intra uterine foetal blood transfusion is the only hope of prolonging pregnancy and salvaging such foetuses.Key Words: Rh-isoimmunisation, Middle cerebral artery peak systolic velocity, Foetal anaemia, Foetal blood transfusion  相似文献   
106.
The aim was to evaluate the effect of HTK compared to UW and Euro-Collins (EC) on the initial graft function and long term graft survival in two prospective randomized studies. Only kidneys from heart-beating, kidney-only or kidney + heart donors were eligible for entry. Initial non-function (INF) was defined as the absence of life-sustaining renal function, requiring dialysis treatment on two or more occasions, during the first week after transplantation. To evaluate the contribution of the preservation solutions on INF in relation to other factors, a multivariate, 2-step logistic regression model was used. Randomization was performed between July 1990 and September 1992. The UW-HTK study comprised 342 donors and 611 transplants (UW: 168 donors and 297 transplants, HTK: 174 donors and 314 transplants). In the EC-HTK study 317 donors and 569 transplants were included (EC: 155 donors and 277 transplants, HTK: 162 donors and 292 transplants). INF occurred in 33 % of either HTK-(n = 105) or UW-(n = 99) preserved kidneys (P = NS), and in 29 % of the HTK-(n = 85) and in 43 % of the EC-(n = 119) preserved kidneys (P = 0.001). Multivariate analysis showed no significant influence of the preservation solution on the incidence of INF in the UW-HTK study, but factors contributing to INF were donor age, cause of death, retransplantation, and cold ischemic period. The EC-HTK study showed a significantly higher risk of INF, using EC as preservation, in addition to cold ischemic period and donor quality. The 3-year graft survival of HTK-preserved kidneys was 73 %, compared to 68 % for UW-preserved kidneys in the UW-HTK study (P = NS); while the 3-year graft survival of HTK preserved kidneys was 70 % compared to 67 % for EC-preserved kidneys in the EC-HTK study (P = NS). We can conclude that HTK is comparable to UW in its preservative abilities, using kidneys from heart-beating kidney-only donors, whereas EC as renal preservation solution should be avoided. Received: 2 November 1998 Received after revision: 10 August 1999 Accepted: 16 September 1999  相似文献   
107.
IntroductionWe assessed the practice of surgeons regarding venous thromboembolism (VTE) chemical prophylaxis for total hip replacement (THR) and total knee replacement (TKR), before and after issuing of updated National Institute for Health and Care Excellence (NICE) guidance in 2018.MethodsA survey, circulated through the British Hip Society and regional trainee networks/collaboratives, was completed by 306 UK surgeons at 187 units. VTE chemical prophylaxis prescribing patterns for surgeons carrying out primary THR (n=258) and TKR (n=253) in low-risk patients was assessed after publication of 2018 NICE recommendations. Prescribing patterns before and after the NICE publication were subsequently explored.ResultsFollowing the new guidance, 34% (n=87) used low-molecular-weight heparin (LMWH) alone, 33% (n=85) aspirin (commonly preceded by LMWH) and 31% (n=81) direct oral anticoagulants (DOACs: with/without preceding LMWH) for THR. For TKR, 42% (n=105) used aspirin (usually monotherapy), 31% (n=78) LMWH alone and 27% (n=68) DOAC (with/without preceding LMWH). NICE guidance changed the practice of 34% of hip surgeons and 41% of knee surgeons, with significantly increased use of aspirin preceded by LMWH for THR (before=25% vs after=73%; p<0.001), and aspirin for TKR (before=18% vs after=84%; p<0.001). Significantly more regimens were NICE guidance compliant after the 2018 update for THR (before=85.7% vs after=92.6%; p=0.011) and TKR (before=87.0% vs after=98.8%; p<0.001).ConclusionOver one-third of surveyed surgeons changed their VTE chemical prophylaxis in response to 2018 NICE recommendations, with more THR and TKR surgeons now compliant with latest NICE guidance. The major change in practice was an increased use of aspirin for VTE chemical prophylaxis.  相似文献   
108.
EfectsofelectroacupunctureongastricmucosalbloodflowandtransmucosalpotentialdiferenceinstressratsXUGuanSun1,SUNYong1,WANGZhe...  相似文献   
109.
110.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号