全文获取类型
收费全文 | 1253篇 |
免费 | 67篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 70篇 |
妇产科学 | 10篇 |
基础医学 | 158篇 |
口腔科学 | 22篇 |
临床医学 | 154篇 |
内科学 | 292篇 |
皮肤病学 | 52篇 |
神经病学 | 34篇 |
特种医学 | 298篇 |
外科学 | 49篇 |
综合类 | 23篇 |
预防医学 | 41篇 |
眼科学 | 5篇 |
药学 | 87篇 |
中国医学 | 4篇 |
肿瘤学 | 75篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 15篇 |
2014年 | 13篇 |
2013年 | 42篇 |
2012年 | 22篇 |
2011年 | 13篇 |
2010年 | 37篇 |
2009年 | 57篇 |
2008年 | 23篇 |
2007年 | 53篇 |
2006年 | 21篇 |
2005年 | 21篇 |
2004年 | 14篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 23篇 |
2000年 | 21篇 |
1999年 | 33篇 |
1998年 | 74篇 |
1997年 | 82篇 |
1996年 | 106篇 |
1995年 | 62篇 |
1994年 | 61篇 |
1993年 | 53篇 |
1992年 | 20篇 |
1991年 | 21篇 |
1990年 | 27篇 |
1989年 | 42篇 |
1988年 | 42篇 |
1987年 | 35篇 |
1986年 | 49篇 |
1985年 | 47篇 |
1984年 | 12篇 |
1983年 | 17篇 |
1982年 | 15篇 |
1981年 | 10篇 |
1980年 | 16篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 15篇 |
1975年 | 13篇 |
1973年 | 4篇 |
排序方式: 共有1376条查询结果,搜索用时 15 毫秒
81.
Magnac C Sutton L Cazin B Laurent C Binet JL Merle-Béral H Dighiero G Maloum K 《Hematology and Cell Therapy》1999,41(1):13-18
In the absence of specific chromosomal translocations the best method for detecting minimal residual disease (MRD) in B cell malignancies is based on the uniqueness of immunoglobulin (Ig) genes rearrangement. We here report a very sensitive method for assessing MRD in complete hematological remission (CHR) chronic lymphocytic leukemia (CLL) patients as defined by the international workshop on CLL (IWCLL). Patients: Twelve CLL patients in CHR and complete phenotypic remission (CPR) were included in the study. Eight of them received Fludarabine (FDR), one was treated by Chop regimen, and the remaining 3 were rescued by polychemotherapy followed by autologous bone marrow transplantation (ABMT). Methods: DNA extracted from peripheral blood lymphocytes (PBL) of each patient was amplified with VH family specific and framework 3 primers in 5 and a consensus JH primer in 3, before treatment and sequentially after the CPR completion. When no clonal rearrangement could be detected by this assay, the CDR3 sequence specific probe of the clone was used as the 3 primer, associated to the VH family specific primer in 5. PCR products were analyzed by classical procedures in agarose and/or acrylamide gels. Results: Mixtures of leukemic cells and normal PBL showed detection of a single leukemic cell among more than 105 normal cells. Four out of the 12 patients achieved molecular remission (MR) when employing CDR3 amplifification. All 3 autografted patients were in MR, whereas only one out of the 9 patients treated by chemotherapy alone achieved MR. When using a clone specific probe, a clonal signal was observed in all cases but one (ABMT). Results presented here confirm that MR may be achieved in a few cases of B-CLL. Further studies are needed to determine the exact relationship between MRD and clinical outcome.This work was supported by a grant from Schering S.A. 相似文献
82.
Volumetric rendering of MR images 总被引:1,自引:0,他引:1
The authors developed new techniques for three-dimensional display of magnetic resonance (MR) images that preserve soft-tissue definition, are fully automatic, and work with routinely used section thicknesses. MR images are segmented, selectively enhanced, and displayed by means of a volumetric rendering algorithm. These techniques were used to illustrate normal anatomy of the brain, knee, and liver. Three-dimensional rendering of balanced spin-echo images shows the ventricles and extracerebral veins and of T1-weighted images, the sulci and gyri. The large hepatic and portal vessels can be seen with these enhancement techniques. Three-dimensional views of the knee reveal articular surfaces of the tibia and clearly depict menisci and posterior and anterior cruciate ligaments. These techniques make it possible to image multiple soft tissues simultaneously while preserving the detail contained in the original images. Three-dimensional presentation of complex, overlapping anatomic regions is helpful in surgical planning and should lead to improved diagnosis. 相似文献
83.
Hasegawa BH; Naimuddin S; Dobbins JT d; Mistretta CA; Peppler WW; Hangiandreou NJ; Cusma JT; McDermott JC; Kudva BV; Melbye KM 《Radiology》1986,159(2):537-543
The feasibility of producing patient-specific beam attenuators for chest radiography has been investigated using an anthropomorphic phantom and a human volunteer. A low-dose test exposure is digitized, processed, and used to print a small cerium filter, which is placed in the x-ray beam near the collimator. The final radiograph is recorded on film. The technique results in relatively uniform film exposure, so that structures in all regions of the chest are simultaneously displayed with optimal film contrast. The equalized exposure improves image quality in the normally underpenetrated regions and reduces the role of cross-scatter from the lungs. The image is analogous to optical or computer-processed unsharp masking techniques, but the processing is accomplished in the x-ray beam and results in an improved exposure distribution, giving advantages that cannot be achieved with image processing techniques alone. 相似文献
84.
JC Szepietowski† J Salomon† P Pacan‡ E Hrehorów† A Zalewska§ 《Journal of the European Academy of Dermatology and Venereology》2008,22(7):795-799
The aim of this study was to determine the frequency of body dysmorphic disorder (BDD) identified by Polish dermatologists and to evaluate the treatment modalities applied by them.
Methods A specially designed questionnaire was distributed to 172 dermatologists. A total of 118 doctors responded (68.6%). The dermatologists were asked regarding demographic data, frequency of BDD in their everyday practice and methods of treatment they used in managing BDD patients.
Results During the whole working period, over the half of dermatologists (64%) had observed at least one BDD patient in their practice. One fifth (20%) of the respondents observed 1 or 2 BDD cases during the past 5 years, 14% observed 3 to 5 such patients, 7% observed 5 to 10 BDD cases, and 5% of the doctors reported seeing more than 10 BDD patients within this period. Almost 18% of dermatologists were currently treating a BDD patient. Our data show that 40.7% of the respondents always ask and 28.8% often ask for a psychiatric opinion. More experienced dermatologists statistically more frequently ( P < 0.05) obtained a psychiatric opinion about their patients. Only a small group of dermatologists (15.3%) use their own pharmacological treatment. If they do so, they first use anxiety-relieving drugs and placebo.
Conclusion BDD is a quite common disorder; however, not all dermatologists are sufficiently prepared to treat it. There is an urgent need for training of dermatologists on the effective approach to psychodermatoses. 相似文献
Methods A specially designed questionnaire was distributed to 172 dermatologists. A total of 118 doctors responded (68.6%). The dermatologists were asked regarding demographic data, frequency of BDD in their everyday practice and methods of treatment they used in managing BDD patients.
Results During the whole working period, over the half of dermatologists (64%) had observed at least one BDD patient in their practice. One fifth (20%) of the respondents observed 1 or 2 BDD cases during the past 5 years, 14% observed 3 to 5 such patients, 7% observed 5 to 10 BDD cases, and 5% of the doctors reported seeing more than 10 BDD patients within this period. Almost 18% of dermatologists were currently treating a BDD patient. Our data show that 40.7% of the respondents always ask and 28.8% often ask for a psychiatric opinion. More experienced dermatologists statistically more frequently ( P < 0.05) obtained a psychiatric opinion about their patients. Only a small group of dermatologists (15.3%) use their own pharmacological treatment. If they do so, they first use anxiety-relieving drugs and placebo.
Conclusion BDD is a quite common disorder; however, not all dermatologists are sufficiently prepared to treat it. There is an urgent need for training of dermatologists on the effective approach to psychodermatoses. 相似文献
85.
直到最近为止,冠心病的内科治疗原则仍是降低心肌需氧量。由于粥样硬化病变一直认为是固定不变的狭窄,不可能增加冠脉血流量,因此认为用药物扩张冠状动脉是徒劳的。在近几年内这些概念有了基本转变。然而仅能引起远端心肌内小动脉扩张的药物却起着相反的作用。当心外膜冠状动脉有粥样硬化时,冠状小动脉扩张可加重血流分布异常,导致心肌缺血。冠状循环由近端大冠状动脉及其分枝小动脉组成的心肌内动脉网构成。近端大冠状 相似文献
86.
Mercado S; Hunter DW; Castaneda-Zuniga WR; Amplatz K; Young AT; Cardella JF; Lange PH; Hulbert JC; Reddy P 《Radiology》1986,158(1):207-209
Percutaneous nephrostolithotomy, which can require a double puncture, is presently the method of choice in our institution for the removal of renal stones. Patients that underwent this procedure were evaluated to identify the possible reasons for the double puncture. Of 200 patients evaluated, 14 needed a second tract. The three variables that determined whether a second puncture was needed, in order of importance, were number and size of the stones, with second tracts needed in patients with multiple stones and staghorn calculi; anatomical variations of the renal collecting system itself, with bifid systems the most significant anatomic variation; and the dexterity of the radiologist in performing the puncture and the ability of the urologist to extract the stone. Second tracts were needed more frequently in patients who presented with stones in both the lower and middle poles of the collecting systems. 相似文献
87.
The preservation of red cell antigens at low ionic strength 总被引:1,自引:0,他引:1
Low-ionic-strength saline (LISS) techniques permit a safe and substantial reduction in incubation time and have therefore become the method of choice for antibody detection and compatibility testing in many transfusion laboratories. Consequently, the supply of reagent red cells (RBCs) in a low-ionic-strength preservative solution would remove the daily need for laboratories to wash and resuspend cells in LISS before use. However, the storage of fresh RBCs at low ionic strength in the presence of aminoglycoside antibiotics can cause a rapid loss of certain antigens, possibly as a result of the release of proteolytic enzymes from contaminating white cells. This article describes a low-ionic-strength solution that achieves preservation of antigens on liquid nitrogen-frozen-thawed RBCs for 21 days' storage at 4 degrees C. 相似文献
88.
Effects of anaerobiosis upon morphology and energy metabolism of alveolar macrophages cultured in gas phase 总被引:3,自引:0,他引:3
M Cazin D Paluszezak A Bianchi J C Cazin C Aerts C Voisin 《The European respiratory journal》1990,3(9):1015-1022
Metabolic and morphological effects of anoxia were studied in alveolar macrophages obtained by lung lavage from guinea-pigs by means of an original method of cell culture allowing direct contact with air without interposition of liquid medium. After selection by glass adherence, alveolar cells were layered on a porous membrane applied to the surface of a reservoir filled with nutrient medium. Alveolar macrophages were then cultured in gas phase under either aerobic or anaerobic conditions for 24, 48 and 72 h. Cellular adenosine triphosphate (ATP) content, an indicator of cell vitality, significantly decreased by 68 and 88% after 48 and 72 h of exposure to anaerobic environment, respectively. Significant increases in lactate production (68% at 24 h) and in glucose uptake (125% at 24 h), evidence of marked glycolytic activity, occurred before these falls in intracellular ATP and parallel decreases in culture medium pyruvate level (76 and 85% at 48 and 72 h, respectively). The shift of energy metabolism resulted in cell death after 72 h, as noted by morphological degeneration and decreased cellular ATP content. Twenty-four hour re-exposure to normoxic atmosphere showed that recovery was possible when duration of anaerobiosis did not exceed 48 h. This reversibility in anoxic cell injury has been related to plasma membrane integrity. The results of these studies indicate that alveolar macrophage resistance to anaerobiosis is limited as ATP content falls and morphological degeneration occurs after 48 h. This novel approach of anaerobic effects at the cell level should be adaptable to investigations of activity and, in particular, the mechanisms of metabolic activity of antianoxic drugs. 相似文献
89.
Prostatic evaluation by transrectal sonography with histopathologic correlation: the echopenic appearance of early carcinoma 总被引:6,自引:0,他引:6
Fifty-two patients with clinical stage A and B carcinomas of the prostate were imaged by ultrasound (US) transrectally with a 5-MHz linear array transducer and transabdominally with a 3-MHz sector scanner prior to radical prostatectomy. The fresh specimens of 44 prostate glands were scanned in a water bath with a 5-MHz linear array transducer in multiple planes. In all cases, histopathologic correlation was obtained. Prostatic carcinoma presented as an echopenic lesion in 54% of the specimens, as a slightly hypoechoic area in 22%, and could not be identified in 24% because of its isoechoic characteristics. In contrast to many previous reports, no instance of echogenic cancer was observed. 相似文献
90.
Venous clots: evaluation with MR imaging 总被引:2,自引:0,他引:2
In vitro and in vivo studies were performed to determine the proton relaxation and imaging characteristics of static blood and acute and organized clot in canine jugular veins. In vivo, it was found that two inversion recovery sequences using a short inversion time (100 msec) demonstrated better differentiation of signal intensity of intravascular clot from surrounding soft tissues than did standard T1- and T2-weighted sequences. In vitro, quantitative measurements showed marked reduction of both T1 and T2 relaxation time of acute clot compared with stagnant blood. In addition, the T1 relaxation time, and to a lesser extent the T2 relaxation time, shortened as the clot aged, indicating a potential role for magnetic resonance imaging in determining the age of venous thrombi. 相似文献