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   3043篇
  免费   186篇
  国内免费   13篇
耳鼻咽喉   21篇
儿科学   62篇
妇产科学   65篇
基础医学   339篇
口腔科学   113篇
临床医学   230篇
内科学   788篇
皮肤病学   44篇
神经病学   368篇
特种医学   277篇
外国民族医学   1篇
外科学   324篇
综合类   20篇
预防医学   106篇
眼科学   22篇
药学   139篇
中国医学   2篇
肿瘤学   321篇
  2023年   16篇
  2022年   25篇
  2021年   45篇
  2020年   35篇
  2019年   43篇
  2018年   44篇
  2017年   48篇
  2016年   48篇
  2015年   72篇
  2014年   92篇
  2013年   101篇
  2012年   149篇
  2011年   165篇
  2010年   101篇
  2009年   95篇
  2008年   145篇
  2007年   164篇
  2006年   143篇
  2005年   132篇
  2004年   142篇
  2003年   97篇
  2002年   76篇
  2001年   68篇
  2000年   99篇
  1999年   77篇
  1998年   65篇
  1997年   69篇
  1996年   74篇
  1995年   64篇
  1994年   63篇
  1993年   43篇
  1992年   51篇
  1991年   52篇
  1990年   48篇
  1989年   49篇
  1988年   48篇
  1987年   38篇
  1986年   53篇
  1985年   46篇
  1984年   24篇
  1983年   33篇
  1982年   22篇
  1981年   15篇
  1980年   14篇
  1979年   16篇
  1978年   15篇
  1977年   19篇
  1976年   20篇
  1975年   18篇
  1969年   15篇
排序方式: 共有3242条查询结果,搜索用时 15 毫秒
71.
ras and c-myc protein expression in colorectal carcinoma   总被引:6,自引:0,他引:6  
This study was performed to determine the correlation of tumor ras and c-myc oncogene expression with clinical and prognostic variables in patients prone to develop colorectal cancer. One hundred eighteen patients with colorectal cancer were studied; mean age was 40 years. Fifty-three were young patients (age 40 or less), 49 had ulcerative colitis, and 16 had multiple polyposis coli. Immunoperoxidase stains of paraffin-embedded cancer sections were performed for the c-myc and ras proteins. ras staining was found to correlate with Dukes stage and prognosis. Patients with tumors negative for ras protein stain had an actuarial five-year survival of 61 percent versus 44 percent for those tumors with a positive stain (P less than 0.05). This correlation was not seen with the c-myc stain. Positive ras oncogene stain appears to be a useful indicator of advanced stage and poor prognosis in colorectal cancer occurring in cancer-prone patients.  相似文献   
72.
To characterize the heterogeneity of severe (type III) von Willebrand disease (vWD), plasma and platelet von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (Ricof) were measured in 28 obligatory heterozygotes (ie, parents or children of probands from 15 different kindreds with severe vWD). On the average, heterozygotes had low levels of vWF in both platelets and plasma. There was, however, considerable heterogeneity, with four distinct patterns. Eleven heterozygotes had concordant reduction of vWF:Ag and Ricof in both plasma and platelets; five had low levels of vWF:Ag and Ricof in plasma contrasting with normal levels in platelets; eight had a peculiar pattern, the reverse of the above (ie, low levels in platelets and normal levels in plasma); and in one, both vWF measurements were normal in plasma and platelets. These patterns were genetically determined: they were consistent in four couples of consanguineous heterozygotes and in two couples carrying the same gene deletion. Only the remaining three heterozygotes had no clearly identifiable pattern. Other findings of this study were that although most of the heterozygotes had normal bleeding times, the 7 of 28 who had prolonged bleeding times had concordantly low levels of vWF measurements in both plasma and platelets. In conclusion, this large series of obligatory heterozygotes provides evidence for phenotypic and genotypic heterogeneity of severe vWD.  相似文献   
73.
This randomized phase III clinical trial explored the efficacy of DaunoXome (DNX) versus Daunorubicin (DNR) in acute myeloid leukaemia (AML) patients aged >60 years. Three hundred and one AML patients were randomized to receive DNR (45 mg/m(2) days 1-3) or DNX (80 mg/m(2) days 1-3) plus cytarabine (AraC; 100 mg/m(2) days 1-7). Patients in complete remission (CR) received a course of the same drugs as consolidation and then were randomized for maintenance with AraC+ all trans retinoic acid or no further treatment. Among 153 patients in the DNR arm, 78 (51.0%) achieved CR, 55 (35.9%) were resistant and 20 (13.1%) died during induction. Among 148 patients in the DNX arm, 73 (49.3%) achieved CR, 47 (31.8%) were resistant and 28 (18.9%) died during induction. Univariate analysis showed no difference as to induction results. After CR, DNX showed a higher incidence of early deaths (12.5% vs. 2.6% at 6 months, P = 0.053) but a lower incidence of relapse beyond 6 months (59% vs. 78% at 24 months, P = 0.064), with a cross in overall survival (OS) and disease-free survival (DFS) curves and a later advantage for DNX arm after 12 months from diagnosis. DNX seems to improve OS and DFS in the long-term follow-up, because of a reduction in late relapses.  相似文献   
74.
Eight laboratories in six countries cooperated to clarify several issues concerning the phenotypes of heterozygous carriers of hemophilia "A." Plasma levels of factor VIII (F.VIII:C, formerly VIII:C) and von Willebrand factor (VWF:Ag, formerly VIIIR:Ag) of carriers and normal women were determined by various "in-house" methods; a single lyophilized plasma standard was used for all assays. Analysis of the collated data from 336 carriers (296 obligatory carriers and 40 sporadic carriers) and 137 normal women showed that there was no difference in the F.VIII:C levels of "paternal" carriers (women who had obtained the abnormal gene from their fathers) and "maternal" carriers. Neither was there a difference in the VWF:Ag levels of normal women and either type of carrier. Age was found to have a significant effect on both F.VIII:C and VWF:Ag, values being higher at very young and very old ages, the minima occurring in the 25- to 30-year range. ABO blood type had a striking effect. Women of types A, B, and AB (designated non- O in the study), both normals and carriers, had significantly higher levels of both factors than did women of type O. Analysis by laboratories showed that differences in mean levels of both factors between laboratories were highly significant. It was concluded that age, ABO blood type, and laboratory variation should be taken into account in carrier detection.  相似文献   
75.
76.
Fludarabine plus cytarabine (Ara-C) and idarubicin (FLAI) is an effective and well-tolerated induction regimen for the treatment of acute myeloid leukaemia (AML). This phase III trial compared the efficacy and toxicity of FLAI versus idarubicin plus Ara-C and etoposide (ICE) in 112 newly diagnosed AML patients <60 years. Fifty-seven patients received FLAI, as the first induction-remission course, and 55 patients received ICE. Post-induction treatment consisted of high-dose Ara-C (HDAC). After HDAC, patients in complete remission (CR) received a second consolidation course (mitoxantrone, etoposide, Ara-C) and autologous stem cell transplantation (auto-SCT) or allogeneic (allo)-SCT, according to the age, disease risk and donor availability. After a single induction course, CR rate was 74% in the FLAI arm and 51% in the ICE arm (P = 0.01), while death during induction was 2% and 9% respectively. Both haematological (P = 0.002) and non-haematological (P = 0.0001) toxicities, especially gastrointestinal (i.e. nausea, vomiting, mucositis and diarrhoea), were significantly lower in FLAI arm. In both arms, relapses were more frequent in patients who were not submitted to allo-SCT. After a median follow-up of 17 months, 30% and 38% of the patients are in continuous CR in FLAI and ICE arm respectively. Our prospective randomised study confirmed the anti-leukaemic effect and the low toxic profile of FLAI as induction treatment for newly diagnosed AML patients.  相似文献   
77.
Insulin receptors on leukemia and lymphoma cells   总被引:1,自引:0,他引:1  
Chen  PM; Kwan  SH; Hwang  TS; Chiang  BN; Chou  CK 《Blood》1983,62(2):251-255
Tumor cells obtained from leukemia and lymphoma patients were investigated for specific insulin receptors. Using radioactive 125I- labeled insulin, specific insulin binding sites were demonstrated on most acute lymphocytic leukemia (ALL) and acute myelocytic leukemia (AML) cells, including acute promyelocytic leukemia (APL), chronic myelocytic leukemia (CML), and acute monocytic leukemia (AMoL) cells. Insulin receptors were not found on chronic lymphocytic leukemia (CLL) and malignant lymphoma (ML) cells. Specific insulin binding sites were also found on monocytes and thymocytes after treatment with phytohemagglutinin (PHA-P), but not on inactivated tonsil cells, peripheral blood lymphocytes, or thymocytes. There was no inverse correlation between the content of insulin receptors and the basal level of circulating insulin. These data suggest that the insulin receptor may be a new marker of acute leukemia and chronic myelocytic leukemia.  相似文献   
78.
New amphiphilic block copolymers Si‐EFSx composed of a poly(dimethyl siloxane) (Si) block and a poly(4‐(triethyleneglycol monomethyl ether)‐2,3,5,6‐tetrafluorostyrene) (EFS) block are synthesized by atom transfer radical polymerization (ATRP) starting from a bromo‐terminated Si macroinitiator. Similarly, new hydrophobic block copolymers Si‐FSy consisting of an Si block and a poly(pentafluorostyrene) (FS) block are prepared for comparison. X‐ray photoelectron spectroscopy (XPS) analysis on block copolymer films reveals that the Si block is concentrated at the polymer–air interface, while the EFS block is located in the layers underneath. The same polymer films undergo a marked surface reconstruction after immersion in water for 7 d, as probed by XPS. This phenomenon involves the exposure of the hydrophilic oxyethylenic chains to contact water. Such surface reconstruction is even more drastic when an amphiphilic block copolymer is dispersed in a cross‐linked poly(dimethyl siloxane) matrix film.

  相似文献   

79.

Background

The EINSTEIN-Jr program will evaluate rivaroxaban for the treatment of venous thromboembolism (VTE) in children, targeting exposures similar to the 20 mg once-daily dose for adults.

Methods

This was a multinational, single-dose, open-label, phase I study to describe the pharmacodynamics (PD), pharmacokinetics (PK) and safety of a single bodyweight-adjusted rivaroxaban dose in children aged 0.5–18 years. Children who had completed treatment for a venous thromboembolic event were enrolled into four age groups (0.5–2 years, 2–6 years, 6–12 years and 12–18 years) receiving rivaroxaban doses equivalent to 10 mg or 20 mg (either as a tablet or oral suspension). Blood samples for PK and PD analyses were collected within specified time windows.

Results

Fifty-nine children were evaluated. In all age groups, PD parameters (prothrombin time, activated partial thromboplastin time and anti-Factor Xa activity) showed a linear relationship versus rivaroxaban plasma concentrations and were in line with previously acquired adult data, as well as in vitro spiking experiments. The rivaroxaban pediatric physiologically based pharmacokinetic model, used to predict the doses for the individual body weight groups, was confirmed. No episodes of bleeding were reported, and treatment-emergent adverse events occurred in four children and all resolved during the study.

Conclusions

Bodyweight-adjusted, single-dose rivaroxaban had predictable PK/PD profiles in children across all age groups from 0.5 to 18 years. The PD assessments based on prothrombin time and activated partial thromboplastin time demonstrated that the anticoagulant effect of rivaroxaban was not affected by developmental hemostasis in children.

Trial registration

ClinicalTrials.gov number, NCT01145859.
  相似文献   
80.

Essentials

  • The role of cerebral venous thrombosis (CVT) recanalization on neurologic outcome is still debated.
  • We studied a large cohort of 508 CVT patients with 419 patient years of radiological follow‐up.
  • Recanalization rate is high during the first months after CVT and neurologic outcome is favorable.
  • High recanalization grade of CVT independently predicts good neurological outcome.

Summary

Background

Studies with limited sample size and with discordant results described the recanalization time‐course of cerebral venous thrombosis (CVT). The neurological outcome after a first episode of CVT is good, but the role of recanalization on neurological dependence is still debated.

Objectives

The aim of the study is to assess the recanalization rate after cerebral venous thrombosis (CVT) and its prognostic role in long‐term neurological outcome.

Patients/Methods

In a retrospective observational multicenter cohort study, patients with an acute first episode of CVT with at least one available imaging test during follow‐up were enrolled. Patency status of the vessels was categorized as complete, partial or not recanalized. Neurological outcome was defined using the modified Rankin scale (mRS) as good (mRS = 0–1) or poor (mRS = 2–6).

Results

Five‐hundred and eight patients (median [IQR] age, 39 [28.5–49] years; 26% male) were included. Complete or partial recanalization was not differently represented in patients undergoing scans at different periods of time (from 28‐day to 3 month‐period up to a 1–3 year‐period). mRS at the time of follow‐up imaging was available in 483 patients; 92.8% of them had a mRS of 0‐1. CVT recanalization (odds ratio [OR], 2.56; 95% confidence interval [CI], 1.59–4.13) was positively associated, whereas cancer (OR, 0.29; 95% CI, 0.09–0.88), and personal history of venous thromboembolism (VTE) (OR, 0.36; 95% CI, 0.14–0.92) were negatively associated as independent predictors of favorable (mRS = 0–1) outcome at follow‐up.

Conclusions

Most patients with a first CVT had complete or partial recanalization at follow‐up. Recanalization was independently associated with a favorable neurological outcome.
  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