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   2037篇
  免费   115篇
  国内免费   20篇
耳鼻咽喉   12篇
儿科学   48篇
妇产科学   33篇
基础医学   320篇
口腔科学   41篇
临床医学   161篇
内科学   361篇
皮肤病学   43篇
神经病学   249篇
特种医学   46篇
外科学   153篇
综合类   5篇
预防医学   275篇
眼科学   20篇
药学   196篇
中国医学   24篇
肿瘤学   185篇
  2023年   17篇
  2022年   29篇
  2021年   42篇
  2020年   26篇
  2019年   48篇
  2018年   51篇
  2017年   43篇
  2016年   45篇
  2015年   41篇
  2014年   72篇
  2013年   87篇
  2012年   136篇
  2011年   161篇
  2010年   72篇
  2009年   80篇
  2008年   139篇
  2007年   147篇
  2006年   144篇
  2005年   141篇
  2004年   126篇
  2003年   122篇
  2002年   102篇
  2001年   17篇
  2000年   21篇
  1999年   21篇
  1998年   18篇
  1997年   9篇
  1996年   5篇
  1995年   18篇
  1994年   9篇
  1993年   5篇
  1992年   13篇
  1991年   4篇
  1990年   11篇
  1989年   14篇
  1988年   13篇
  1987年   14篇
  1986年   8篇
  1985年   7篇
  1984年   8篇
  1983年   10篇
  1982年   6篇
  1981年   4篇
  1979年   4篇
  1977年   6篇
  1976年   8篇
  1975年   5篇
  1973年   4篇
  1970年   5篇
  1962年   3篇
排序方式: 共有2172条查询结果,搜索用时 15 毫秒
1.

Background

We have recently shown that human epididymis protein 4 (HE4) levels correlate with the severity of cystic fibrosis (CF) lung disease. However, there are no data on how HE4 levels alter in patients receiving CFTR modulating therapy.

Methods

In this retrospective clinical study, 3 independent CF patient cohorts (US-American: 29, Australian: 12 and Irish: 19 cases) were enrolled carrying at least one Class III CFTR CF-causing mutation (p.Gly551Asp) and being treated with CFTR potentiator ivacaftor. Plasma HE4 was measured by immunoassay before treatment (baseline) and 1–6?months after commencement of ivacaftor, and were correlated with FEV1 (% predicted), sweat chloride, C-reactive protein (CRP) and body mass index (BMI).

Results

After 1?month of therapy, HE4 levels were significantly lower than at baseline and remained decreased up to 6?months. A significant inverse correlation between absolute and delta values of HE4 and FEV1 (r?=??0.5376; P?<?.001 and r?=??0.3285; P?<?.001), was retrospectively observed in pooled groups, including an independent association of HE4 with FEV1 by multiple regression analysis (β?=??0.57, P?=?.019). Substantial area under the receiver operating characteristic curve (ROC-AUC) value was determined for HE4 when 7% mean change of FEV1 (0.722 [95% CI 0.581–0.863]; P?=?.029) were used as classifier, especially in the first 2?months of treatment (0.806 [95% CI 0.665–0.947]; P?<?.001).

Conclusions

This study shows that plasma HE4 levels inversely correlate with lung function improvement in CF patients receiving ivacaftor. Overall, this potential biomarker may be of value for routine clinical and laboratory follow-up of CFTR modulating therapy.  相似文献   
2.
Technetium-99m sestamibi was used for functional investigation of the muscle perfusion of lower extremities in 35 patients with peripheral vascular disease. The aim was to test what useful information could be obtained by additional imaging of the legs in patients referred for risk stratification with dipyridamole myocardial scanning. Posterior images were acquired over the thighs and calves after postocclusive reactive hyperaemia and at rest. Inter- and intraextremity ratios and differences between the stress and rest data were used for the assessment of abnormal circulation. Arteriography was performed in every case, and surgical procedures or transluminal angioplasty in 31 patients. To estimate diagnostic accuracy, the results of99mTc-sestamibi scintigraphy were compared with those of angiography and the functional consequences of revascularization procedures. The sensitivity and specificity of99mTc-sestamibi scintigraphy were 55% and 25%, respectively, with an overall accuracy of 50%. Apparently methodological error was not responsible for these poor results. Instead, a paradoxically high uptake of the radiopharmaceutical in muscles supplied by significantly stenosed vessels was identified as the main source of both false-negative and false-positive results. This phenomenon resembles the findings of a previous study involving delayed administration of thallium-201 after exercise. In conclusion,99mTc-sestamibi scintigraphy has not proved sufficiently reliable to help in the management strategy for patients with peripheral vascular disease.  相似文献   
3.
BACKGROUND: The diagnosis of analgesic nephropathy has improved significantly with modern imaging techniques. We reviewed a large portion of the Hungarian dialysis population to obtain additional insight into the problem. METHODS: Twenty-two participating dialysis units enrolled 1400 patients on renal replacement therapy between 1 January 1995 and 1 January 1998. Patients with no known aetiology (n = 284) were interviewed and studied with renal imaging. We assessed the presence of decreased renal mass combined with either bumpy contours, papillary calcification, or both. The subjects studied were interrogated extensively. RESULTS: Our survey suggested analgesic nephropathy in 47 of 1400 patients (3.3%), 3-fold higher than the EDTA database estimate for Hungary. The analgesics most commonly abused were phenacetin-containing mixtures. The driving symptoms were mainly headache and joint pain. Cardiovascular complications were more common than in the rest of the dialysis population, independent of smoking and lipid values (P<0.01). CONCLUSIONS: Phenacetin should be banned. Our study results support the need for longitudinal cohort and case-control studies in Hungary.  相似文献   
4.
The first pharmacon with proved efficacy for the treatment of patients with the relapsing-remitting or relapsing-progressive form of multiple sclerosis (MS) was interferon-beta1b (IFN-beta1b). In 1996, we started treating 34 relapsing-remitting (RRMS) and 2 relapsing-progressive MS (RPMS) patients with IFN-beta1b. Of these 36 patients, 28 received continuous medication for 6 years. The primary end point of the study was the effect of 6 years of continuous IFN-beta1b treatment on the annual relapse rate, the secondary end point was the change in the progression index during the 6 years, and the tertiary end point was the alteration in the expanded disability status scale (EDSS) score of the patients. Finally, we give the reasons for the dropouts. The relapse rate decreased by 80.62% (p < 0.001), the mean EDSS score increased significantly, by approximately 0.5 points, to 2.21 +/- 1.48 (p = 0.016), and the reduction in the mean progression index was 67.19% (p < 0.001). This increase of < 0.5 point in the EDSS score is appreciably different from the 3-point deterioration expected after 6 years for the natural course of the disease. The significant improvement in the progression index clearly demonstrates that 6 years of IFN-beta1b therapy slowed the progression of the disease, thereby improving the quality of life of these MS patients.  相似文献   
5.
The association between contralateral stimulation and evoked otoacoustic emissions (EOAEs) allows study of sound-evoked olivocochlear feedback and then of the medial olivocochlear system. A method allowing quantification of sound-evoked olivocochlear feedback is proposed. The feedback is present in almost all normal-hearing subjects, but with great interindividual variability. In sensorineural hearing loss, the feedback is present in 20 out of 21 subjects. One paradoxical clinical case is described with a unilateral increase of EOAE intensity during contralateral stimulation.  相似文献   
6.
This case report describes a successful pregnancy and deliveryin a woman presenting with ovarian autoimmunity who had previouslybeen involved in two unsuccessful in-vitro fertilization (IVF)attempts. Ten days before a third attempt, she began a regimenof 25 mg per day of prednisolone which was continued throughoutthe whole IVF protocol. Ovulation was induced by human menopausalgonadotrophin. After administration of 5000 IU of human chorionicgonadotrophin, 18 oocytes were collected. At 48 h after inseminationwith the patient's husband's spermatozoa, four 4-cell pre-embryoswere transferred. A singleton pregnancy developed and led tothe birth of a girl who is doing well 10 months later.  相似文献   
7.
Immunologic typing has demonstrated considerable heterogeneity among the acute leukemias. The most significant recent advance has been development of monoclonal antibody techniques. Some markers identified using these techniques seem to be specific for a given stage of maturation of one lymphoid or myeloid cell line. Most acute lymphoblastic leukemias (ALLs) are malignant proliferations whose differentiation appears to have become 'stuck' at one stage of maturation. Results of immunologic typing correlate well with the other clinical and biological data. For prognostic purposes, several patterns can be identified. Among B line ALLs, four varieties have been differentiated, i.e., CD10 negative ALLs, common ALLs, pre-B ALLs, and B ALLs. T ALLs include a broad spectrum of heterogeneous proliferations whose immunologic classification is made difficult by the large number of phenotypes encountered. Among acute myeloblastic leukemias (AMLs), some highly undifferentiated forms have been recognized, by means of immunologic typing, as originating in one of the myeloid cell lines. However, the nosologic and prognostic significance of these studies is less obvious than in ALLs.  相似文献   
8.
Patients with renal failure represent a population at risk for hepatitis B, since only 50 to 60% of them develop protective humoral responses after vaccination. As this could be due to an altered regulation of cellular immune responses, the objectives of the present study were to evaluate the proliferative abilities of lymphocytes from patients with chronic renal failure after stimulation in vitro with a mitogen (pokeweed mitogen [PWM]) or HBsAg. In order to differentiate between the immunodeficiency associated with renal failure and that due to immunosuppression posttransplantation, the same subjects were tested before and 4 months after kidney transplantation. The lymphoproliferation assay used was performed by flow cytometry, which is based on sequential analysis of the cell cycle and which allows analysis of cytokine production. Serologically, the group of 36 patients tested comprised 22% nonresponders, 30% poor responders, and 48% responders. Lymphocyte growth was observed for all patients after stimulation with PWM, indicating that these cells had the capacity to proliferate in vitro. The level of lymphoproliferation in response to PWM was significantly reduced after transplantation, yet both before and after transplantation, all serologic nonresponders developed cellular responses to at least two vaccines. No correlation between humoral and cellular responses was shown. Proliferating cells were lymphocytes, which mostly secreted interleukin 4 (IL-4) and IL-10 for the three serologic groups. This study suggests that even when repeated vaccination fails to induce significant antibody levels in patients with renal failure, specific HBs cellular responses develop, and these may prove to be efficient in protecting these patients against hepatitis B.  相似文献   
9.
Following up the results of a previous population association study (Lakatos et al. [2000: Mol Psychiatry 5:633-637; Lakatos et al. [2002: Mol Psychiatry 7:27-31]) by analyses based on parental genetic data confirmed the link between infant attachment and the dopamine D4 receptor (DRD4) gene. Extended transmission disequilibrium tests (ETDT) were performed to determine whether biased transmission of exon III 48 basepair repeat alleles occurred to infants displaying disorganized and secure attachment behavior with their mothers. The overall allele-wise TDTs were significant for both groups (P = 0.038 and 0.020, respectively): a trend for preferential transmission of the seven-repeat allele to disorganized infants was observed (TDT(chi)(2) = 3.27, df = 1, P = 0.071), and there was a significant non-transmission of the same allele to securely attached infants (TDT(chi)(2) = 6.00, df = 1, P = 0.014). Analysis of haplotypes of the exon III repeat and the -521 C/T promoter polymorphisms in family trios showed that the transmission bias in the larger secure group was due to the low-rate transmission of the T.7 haplotype containing both the seven-repeat and the -521 T alleles (TDT(chi)(2) = 4.46, df = 1, P = 0.035). This suggests that not carrying the T.7 haplotype of the DRD4 gene may act as a resilience factor in the optimal development of early attachment.  相似文献   
10.
While low avidity ligation of the T cell receptor (TCR) leads to positive selection and further maturation of developing thymocytes providing the immune system with mature CD4(+) and CD8(+) (single positive) T cells, high avidity ligation triggers negative selection by apoptotic cell death and therefore the TCR repertoire is purged of autoreactive T cells. On peripheral T cells, however, high avidity ligation of the TCR triggers activation and survival not death. In the present study we used concanavalin A (Con A) and alpha-CD3 epsilon antibody to investigate a possible survival mechanism in connection with TCR ligation. Con A and alpha-CD3 epsilon were used in the study for the following reasons: (1) they both mimic the effects of high avidity TCR ligation by activating peripheral T cells, and (2) they trigger distinctively different physiological changes in developing thymocytes. While Con A supports events associated with cellular survival, alpha-CD3 epsilon induces apoptotic cell death. In our experimental system the TCR was cross-linked by Con A and alpha-CD3 epsilon in thymocytes of major histocompatibility complex (MHC) deficient thymus organ cultures, where signals from the TCR can be triggered on zero background signal level. We have found that TCR cross-linking by Con A and not by alpha-CD3 epsilon decreases the gene and protein expression of the pro-apoptotic molecule, Bad; and that Con A is capable of the activation of the survival signalling pathway including protein kinase B (Akt/PKB) independently of phosphatidyl inositol kinase (PI3K).  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