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   2986篇
  免费   144篇
  国内免费   9篇
耳鼻咽喉   15篇
儿科学   46篇
妇产科学   57篇
基础医学   437篇
口腔科学   35篇
临床医学   207篇
内科学   830篇
皮肤病学   37篇
神经病学   168篇
特种医学   152篇
外科学   407篇
综合类   12篇
一般理论   1篇
预防医学   112篇
眼科学   208篇
药学   137篇
中国医学   1篇
肿瘤学   277篇
  2021年   29篇
  2020年   15篇
  2019年   19篇
  2018年   27篇
  2017年   20篇
  2016年   25篇
  2015年   45篇
  2014年   52篇
  2013年   74篇
  2012年   111篇
  2011年   153篇
  2010年   67篇
  2009年   75篇
  2008年   101篇
  2007年   112篇
  2006年   123篇
  2005年   137篇
  2004年   107篇
  2003年   102篇
  2002年   95篇
  2001年   123篇
  2000年   96篇
  1999年   72篇
  1998年   48篇
  1997年   51篇
  1996年   55篇
  1995年   39篇
  1994年   33篇
  1993年   43篇
  1992年   84篇
  1991年   104篇
  1990年   79篇
  1989年   106篇
  1988年   76篇
  1987年   68篇
  1986年   60篇
  1985年   61篇
  1984年   37篇
  1983年   48篇
  1982年   29篇
  1981年   35篇
  1980年   16篇
  1979年   31篇
  1978年   32篇
  1977年   20篇
  1976年   19篇
  1975年   21篇
  1974年   16篇
  1973年   21篇
  1971年   13篇
排序方式: 共有3139条查询结果,搜索用时 421 毫秒
1.
2.
Acute and chronic renal failure in liver transplantation   总被引:9,自引:0,他引:9  
We have performed a retrospective review of the incidence and etiologies of acute renal failure (ARF) in 105 adult patients receiving liver transplants. The prevalence of chronic renal failure was also determined. ARF occurred in 94.2% of these patients. Acute tubular necrosis was the leading cause of ARF and was associated with the highest mortality. Factors associated with increased mortality included: (1) peak serum creatinine greater than 3 mg/dl, (2) multiple liver transplants and (3) the need for dialysis. Pretransplant renal failure did not increase mortality. Chronic renal failure developed in 83% of patients at latest follow-up (mean: 30.5 +/- 7.9 months).  相似文献   
3.
(E)-5-(2-Bromovinyl)-2'-deoxyuridine (1; BrVUdR) inhibits the replication of herpes simplex virus type 1 (HSV-1) and of varicella-zoster virus (VZV) in vitro at concentrations of 0.01 to 0.23 mumol/l, whereas herpes simplex virus type 2 (HSV-2) is influenced only at 5.5 to 27 mumol/l. In comparison to some classical and newly developed antiherpetics, i. e. 5-iodo-2'-desoxyuridine (2; idoxuridine, IDU), 9-beta-D-arabinofuranosyladenine (4; vidarabine Ara-A), 9-(2-hydroxyethoxymethyl) guanine (5; acyclovir, ACV) and 2'-fluoro-5-iodo-1-beta-D-aracytosine (6;FIAC) the following order of decreasing activity was found:1 greater than 6 greater than 5 greater than 2 greater than 4 (against HSV-1) and 6 greater than 2 greater than 5 greater than 1 greater than 4 (against HSV-2). The high selectivity of the antiviral effect of BrVUdR towards HSV-1 and TZV is based on the fact, that proliferation of different mammalian cell lines is inhibited by 50% only at concentrations as high as 90 to 170 mumol/l, resulting in a therapeutical index of 1000 to 10,000. Successful treatment of an HSV-1 encephalitis in mice as well as an HSV-1 keratitis of rabbits confirmed the efficiency of 1 in experimental animal infections. No toxic side effects in both local and systemic applications were observed. Promising data from cell culture and animal experiments recommend 1 as a potential candidate for the local and systemic treatment of HSV-1 and VZV infections in man.  相似文献   
4.
5.
Background/aim  Theoretical considerations support the combination of cryosurgery and topical imiquimod to treat basal cell carcinomas (BCC). The aim of the present study was to test the feasibility and efficacy of 'cryosurgery during continued imiquimod application' ('immunocryosurgery') to treat 'high-risk-for-recurrence' BCCs.
Methods  Thirteen patients with 21 biopsy-proven tumours (4 of 21 relapses after prior surgery) were included. After 2–5 weeks (median, 3) of daily 5% imiquimod cream application, the tumours were treated by liquid N2 cryosurgery (spray, two cycles, 10–20 s) and imiquimod was continued for additional 2–12 weeks (median, 4). The outcome after at least 18 months of follow-up (18–24 months) is currently reported.
Results  Nineteen of 21 tumours responded promptly to immunocryosurgery; two tumours required additional treatment cycles to clear. Thus, the clinical clearance rate was 100%. Only 1 of 21(5%) tumour relapsed after at least 18 months of follow-up (cumulative efficacy: 95%).
Conclusions  'Immunocryosurgery' is a promising non-surgical combination modality to treat 'high-risk-for-recurrence BCCs'. Initial evidence is suggestive of an at least additive effect of the two combined modalities. Further studies comparing immunocryosurgery directly with cryosurgery and imiquimod monotherapies will confirm the reported results.  相似文献   
6.
Chronic hepatitis B virus (HBV) infection affects about 200–400 million people worldwide and represents one of the leading causes for liver cirrhosis and hepatocellular carcinoma. Control over the HBV infection is achieved mainly by vaccination with Hepatitis B surface antigen (HBsAg). HBsAg contains N -linked glycosylation side and is recognized by both MBL-A and MBL-C in a Ca-dependent manner. HbsAg–MBL complexes activate complement and may thus affect humoural immunity. To investigate the role of MBL in humoural responses to HBsAg, we immununized mice that lack both MBL-A and MBL-C proteins with soluble HBsAg. It has been shown that deficiencies in other complement components like C1q, C4 and C3 result in decreased antibody responses. However, MBL double KO animals mounted dramatically increased humoural responses. After priming, MBL double KOs mounted HbsAg-specific IgM responses, which were threefold higher than WT controls. After boosting the HBsAg, total IgG was 10-fold higher in MBL KO than in WT control animals. Similar to the response to HbsAg, other glycosylated soluble antigens (e.g. invertase) induced better humoural responses in MBL double KO animals, suggesting that MBL plays an important role in a negative feedback regulation of adaptive immunity. Reconstitution experiments with rMBL partially rescued the KO phenotype. We propose that the clearance of glycoprotein antigens in MBL KO is handled differently from the WT, resulting in better stimulation of humoural responses. Alternatively, glycoprotein-Ag-MBL-rich complexes inhibit B-cell responsiveness via putative MBL receptors.  相似文献   
7.
Efficient high-frequency body coil for high-field MRI.   总被引:1,自引:0,他引:1  
The use of body coils is favored for homogeneous excitation, and such coils are often paired with surface coils or arrays for sensitive reception in many MRI applications. While the body coil's physical size and resultant electrical length make this circuit difficult to design for any field strength, recent efforts to build efficient body coils for applications at 3T and above have been especially challenging. To meet this challenge, we developed an efficient new transverse electromagnetic (TEM) body coil and demonstrated its use in human studies at field strengths up to 4 T. Head, body, and breast images were acquired within peak power constraints of <8 kW. Bench studies indicate that these body coils are feasible to 8 T. RF shimming was used to remove a high-field-related cardiac imaging artifact in these preliminary studies. P41RR13230  相似文献   
8.
A 53-year-old male with hepatitis C cirrhosis, who had been refused liver transplantation because of hypertrophic cardiomyopathy (HC), underwent nonsurgical septal ablation using alcohol with resolution of his ventricular outflow obstruction. This patient was able to subsequently undergo a successful deceased donor liver transplantation. This is the first reported case of alcohol induced septal ablation being performed in a cirrhotic patient with HC. Such nonsurgical procedures may be attractive in cirrhotic patients who are refused access to liver transplantation because of high surgical risk.  相似文献   
9.
The data concerning the value of duplex sonography in diagnosingparenchymatous renal allograft dysfunction are controversial.Most early studies did not take into consideration the manyfactors influencing resistance parameters. We therefore performeda prospective, biopsy-controlled study with exclusion of allknown sources of error regarding resistance parameters. Furthermorewe investigated the value of a new resistance parameter, thesystolic deceleration percentage. Forty-seven duplex sonographicstudies were performed on 43 patients (30 male, 13 female, medianage 47 years, range 7–70). Fourteen studies were doneon normally functioning grafts (control group) an average of33 days after transplantation. Thirty-three studies were performedon dysfunctional grafts immediately prior to biopsy. Graftswhich had been transplanted more than a year previously or withvascular findings or any other clinical or sonographic pathologyprobably explaining function deterioration were excluded. Inall patients, the resistive index (RI), pulsatility index (PI)and systolic deceleration percentage (DP) were calculated inthe main renal artery and in the interlobar artery. Of the 33grafts with dysfunction, nine had vascular rejection (VR), 11interstitial rejection (IR), 11 cyclosporin A toxicity (CAT)and two other histologies (OR). The mean RI in normal grafts(NO) was 0.71±0.06 in the main artery and 0.68±0.06in the interlobar artery, in VR 0.86±0.12 and 0.80±0.18,in IR 0.72±0.05 and 0.70±0.07, in CAT 0.67±0.06and 0.65±0.07 and in OR 0.64±0.07 and 0.60±0.01.For PI, the values were 1.45±0.23 and 1.41±0.28(NO), 3.5±2.13 and 2.92±2.16 (VR), 1.55±0.26and 1.46±0.33 (IR), 1.32±0.25 and 1.27±0.26(CAT) and 1.30±0.34 and 1.13±0.04 (OR). For DPwe calculated 28±5% and 29±6% (NO), 43±14%and 36±6% (VR), 29±9% and 27±9% (IR), 31±8%and 32±7% (CAT ) and 32±4% and 28±3% (OR).The sensitivity/specificity for VR with a cutoff mean+2 SD was0.44/1 for RI, 0.55/0.97 for PI and 0.33/0.89 for DP. It wasconcluded that:(1) despite the high selection of our patientgroup, diagnostic accuracy of duplex sonography for diagnosingparenchymatous function disorder in renal allograft remainsinsufficient; (2) in vascular rejection only, the resistanceparameters differ significantly from the values of normal allografts;(3) the higher the cutoff of resistance parameters, the betterthe specificity and the worse the sensitivity for diagnosingvascular rejection; (4) of all investigated resistance parameters,the RI is the most practical due to a simple measurement technique.  相似文献   
10.
Outcome in emotionally related living kidney donor transplantation   总被引:9,自引:5,他引:4  
Background. The growing shortage of cadaver kidneys, the limited possibilities to expand the living related donor pool and the good results obtained in our centre with poorly matched cadaver kidneys, led us in 1991 to begin accepting highly motivated, unrelated, living kidney donors who had a strong emotional bond with the recipients. Methods. Between 1 January 1991 and 1 January 1996, 46 potential living kidney donors and their emotionally related recipients were evaluated. Twenty-three cases were accepted for renal transplantation after thorough somatic and psychological evaluation. The mean post-transplant follow-up until 1 April 1996 was of 28±3 months. Compatible blood groups and a negative cross-match were mandatory, but no minimal HLA matching was required. Results. There was a 50% drop-out rate following the initial screening. The main reasons for not performing transplantation were immunological contraindications in 39% of the cases, somatic in 30.5%, psychological in 26% and socioeconomic in 4.5%. In the accepted group of recipients, 48% (11/23) received transplants without chronic dialysis. Donor survival was 91%; two deaths unrelated to nephrectomy occurred 1 year after donation. The 2-year actuarial recipient and graft survivals were 100% and 91% respectively, compared to 99% (recipients) and 93% (grafts) in the non-HLA-identical living related kidney transplant group, and to 93% (recipients) and 83% (grafts) in the cadaver kidney transplant group. Recipient rehabilitation was completed after 4±1 months. Emotionally related donors returned to work 5±2 weeks after nephrectomy, and no donor regretted his decision, even in the case of failure. Conclusions. Kidney transplantation from emotionally related living donors represents a valuable option, allowing more patients with end-stage renal disease to avoid chronic dialysis. Recipient and graft outcome were superior to cadaver kidney transplantation. Motivated and emotionally related donors should be allowed to donate one of their kidneys provided that they are carefully selected and thoroughly informed.  相似文献   
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