全文获取类型
收费全文 | 508篇 |
免费 | 44篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 38篇 |
妇产科学 | 4篇 |
基础医学 | 77篇 |
口腔科学 | 10篇 |
临床医学 | 74篇 |
内科学 | 116篇 |
皮肤病学 | 13篇 |
神经病学 | 23篇 |
特种医学 | 67篇 |
外科学 | 58篇 |
综合类 | 8篇 |
预防医学 | 12篇 |
眼科学 | 4篇 |
药学 | 25篇 |
肿瘤学 | 30篇 |
出版年
2021年 | 16篇 |
2020年 | 10篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 17篇 |
2016年 | 8篇 |
2015年 | 18篇 |
2014年 | 13篇 |
2013年 | 22篇 |
2012年 | 25篇 |
2011年 | 22篇 |
2010年 | 24篇 |
2009年 | 20篇 |
2008年 | 13篇 |
2007年 | 9篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 10篇 |
2002年 | 3篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 22篇 |
1997年 | 19篇 |
1996年 | 22篇 |
1995年 | 16篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 1篇 |
1948年 | 2篇 |
1932年 | 1篇 |
1925年 | 1篇 |
1924年 | 1篇 |
排序方式: 共有560条查询结果,搜索用时 15 毫秒
551.
Luca De Sabato Gabriele Vaccari Philippe Lemey Maria Grazia Amoroso Giovanna Fusco Giovanni Ianiro Ilaria Di Bartolo 《Virus genes》2018,54(6):812-817
The complete and near-complete genome sequences (7206 nt and 7229 nt) of two wild boar HEV strains detected in Southern Italy were obtained by the next generation sequencing. Phylogenetic analysis and p distance comparisons of one of the strains with HEV-3 reference subtype strains confirmed the detection of a subtype 3i (p distance?=?0.110) strain in wild boar, never detected in Italy either in wild boar or pigs. The sequence of the second strain was not classifiable in any of the subtypes defined to date, showing a p distance?>?0.138 and a low nucleotide identity with all HEV reference strains. The virus may represent a novel subtype, with a low relationship to other strains of genotype 3 detected in wild boar, pigs, or humans in Europe. This result suggests the circulation in Italy of an emerging or uncommon HEV strain. Sequencing followed by phylogenetic analyses of the complete HEV coding regions are important tools for understanding the evolutionary and epidemiological dynamics underlying the wide genetic diversity of HEV strains. 相似文献
552.
Dauri M Sidiropoulou T Fabbi E Giannelli M Faria S Mariani P Sabato AF 《Regional anesthesia and pain medicine》2007,32(4):282-287
BACKGROUND AND OBJECTIVES: This prospective randomized controlled trial investigated the clinical efficacy of stimulating catheters for continuous femoral nerve block in patients who underwent anterior cruciate ligament reconstruction. METHODS: Seventy patients were randomized to either a stimulating catheter (SC, n = 35) or a nonstimulating catheter (NSC, n = 35) for femoral nerve block using 25 mL ropivacaine 7.5 mg/mL and clonidine 50 microg injected through the catheter. A single-injection sciatic block was also given to ensure surgical anesthesia. The time to loss of sensation to cold and pinprick of the femoral nerve was registered as the onset time. Data were registered intra- and postoperatively regarding pain scores, adverse effects, and need for supplemental anesthesia and analgesia other than a continuous postoperative infusion of ropivacaine 2 mg/mL through the continuous femoral nerve catheter set at 7 mL/h. RESULTS: Onset time was faster in the SC group (SC: 6.4 +/- 2.5, NSC: 8.3 +/- 2.9 min, P = .006). Visual analog scale pain scores were similar in both groups. The number of patient-controlled regional analgesia boluses (SC: 14.6 +/- 12.6, NSC: 23.2 +/- 13.6 mg ropivacaine 2 mg/mL, P = .008) as well as intravenous rescue ketorolac (SC: 34.3 +/- 35.7, NSC: 54 +/- 39.7 mg, P = .033) administered were higher in the NSC group. CONCLUSION: Although the use of a stimulating catheter was associated with faster onset time for the femoral nerve block and lower additional analgesics postoperatively, the clinical superiority (analgesia; lateral femoral cutaneous, and obturator nerve block) of stimulating catheters was not evident in this clinical setting. 相似文献
553.
554.
555.
Reis MM; Soares SR; Cancado ML; Camargos AF 《Human reproduction (Oxford, England)》1998,13(11):3049-3052
A total of 88 Fallopian tubes from 44 patients was examined with
hysterosalpingo contrast sonography (HyCoSy), hysterosalpingogram (HSG),
and laparoscopic chromopertubation (LC) in order to assess their relative
accuracy for measuring tubal patency. HyCoSy was done by transvaginal
ultrasound and the contrast was SH U 454 (Echovist). The flow of multiple
fractions of the contrast medium through each Fallopian tube was observed
in real time in appropriate imaging planes by means of a transvaginal
probe. Compared with laparoscopic results, we found a sensitivity of 85.2%,
a specificity of 85.2%, a positive predictive value (PPV) of 71.9%, a
negative predictive value (NPV) of 92.9% and concordance (HyCoSy/LC) of
85.2%, while the corresponding values for HSG were sensitivity = 85.2%,
specificity = 83.6%, PPV = 69.7%, NPV = 92.7% and concordance (HSG/LC) of
84.1%. Compared with HSG results, HyCoSy obtained a co-positivity of 66.7%,
a co-negativity of 81.8% and a concordance of 76.1%. In conclusion, HyCoSy
with SH U 454 proved to be a reliable and safe modality for evaluating
tubal patency; it is suitable as an outpatient diagnostic procedure to be
used before more invasive procedures.
相似文献
556.
Ultrastructural analysis of human natural killer cell activation 总被引:3,自引:0,他引:3
In this study we describe characteristic ultrastructural changes of CD3- large granular lymphocytes (LGL), ie, natural killer (NK) cells, following stimulation with recombinant (r) interleukin 2 (IL 2) or r- gamma interferon (r-gamma IFN) and after interaction with K562 target cells (TC) or Sepharose-bound anti-Fc gamma receptor (FcR) monoclonal antibody (MoAb). When compared to resting cells the cytolytic activity of r-IL 2- and r-gamma IFN-stimulated cells against K562 TC was enhanced. The r-IL 2-stimulated LGL were larger and consistently displayed the shape and cytoskeletal rearrangement characteristic of activated cells. The Golgi apparatus was expanded, and the number of electron-dense granules and vesicles was increased. The ultrastructural changes in r-gamma IFN-stimulated LGL were markedly different from those observed following r-IL 2 activation. Cells did not exhibit changes in size, shape, cytoskeletal organization, or in the structure of the Golgi apparatus. However, r-gamma IFN-stimulated cells exhibited distinctive changes in the structure and content of electron-dense granules with deaggregation of the matrix and parallel tubular arrays (PTAs). Within organelles apparently derived from the electron-dense granules, vesicular and tubular structures were noted that may be the morphological equivalent of cytotoxic factors produced by cytolytic effector cells. These ultrastructural observations indicate that r-IL 2 and r-gamma IFN enhance the lytic ability of NK cells by acting on distinct cell machineries. The cytolytic ability was decreased when LGL were pretreated with K562 TC or immobilized anti-FcR antibody. In both experimental conditions cells displayed ultrastructural features indicating activation as well as loss of cytoplasmic granules and other Golgi-derived organelles. Stimulation of r-gamma IFN- or r-IL 2- activated LGL with K562 TC or Sepharose-bound anti-FcR antibody decreased their cytolytic ability, with cells depleted of granules at the ultrastructural level. Intracytoplasmic fusion of granules and a massive release of the granule content were found in r-IL 2-stimulated cells, reminiscent of the mechanism of basophil degranulation. These observations suggest that multiple activation signals involving distinct surface membrane molecules induce release of cytolytic factors by both resting and activated NK cells. 相似文献
557.
AF Goodwin S Oberoi M Landan C Charles J Groth A Martinez C Fairley LA Weiss WE Tidyman OD Klein KA Rauen 《Clinical genetics》2013,83(6):539-544
Cardio‐facio‐cutaneous syndrome (CFC) is a RASopathy that is characterized by craniofacial, dermatologic, gastrointestinal, ocular, cardiac, and neurologic anomalies. CFC is caused by activating mutations in the Ras/mitogen‐activated protein kinase (MAPK) signaling pathway that is downstream of receptor tyrosine kinase (RTK) signaling. RTK signaling is known to play a central role in craniofacial and dental development, but to date, no studies have systematically examined individuals with CFC to define key craniofacial and dental features. To fill this critical gap in our knowledge, we evaluated the craniofacial and dental phenotype of a large cohort (n = 32) of CFC individuals who attended the 2009 and 2011 CFC International Family Conferences. We quantified common craniofacial features in CFC which include macrocephaly, bitemporal narrowing, convex facial profile, and hypoplastic supraorbital ridges. In addition, there is a characteristic dental phenotype in CFC syndrome that includes malocclusion with open bite, posterior crossbite, and a high‐arched palate. This thorough evaluation of the craniofacial and dental phenotype in CFC individuals provides a step forward in our understanding of the role of RTK/MAPK signaling in human craniofacial development and will aid clinicians who treat patients with CFC. 相似文献
558.
559.
C. Catena S. Bernardi N. Sabato A. Grillo M. Ermani L.A. Sechi B. Fabris R. Carretta F. Fallo 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2013,23(4):389-393
Background and aimNon-alcoholic fatty liver disease (NAFLD) has been found to be strongly related to an increased arterial stiffness in patients with essential hypertension, suggesting a pathophysiologic link between major cardiovascular and metabolic abnormalities associated with liver steatosis and the functional and structural alterations of the arterial wall. The aim of our study was to investigate, in a group of essential hypertensive patients without additional cardiovascular risk factors, the relationship between NAFLD and arterial stiffness.Methods and ResultsSixty-eight consecutive patients with essential hypertension underwent 24-h ambulatory blood pressure monitoring (ABPM) and were separated according to the presence (n = 40) or absence (n = 28) of NAFLD at liver ultrasonography. The Ambulatory Arterial Stiffness Index (AASI) and Symmetric AASI (Sym-AASI) were derived from ABPM tracings. Patients with diabetes, obesity, hyperlipidaemia or other risk factors for cardiovascular or liver disease were excluded. Hypertensive patients were compared with a normotensive control group.The two hypertensive groups had comparable age, sex distribution and clinic/ABPM blood pressure levels. In hypertensive patients with NAFLD, body mass index, fasting glucose, insulin, homeostasis model of assessment of insulin resistance index and triglyceride levels were higher, whereas plasma adiponectin was lower than in patients without NAFLD. In hypertensive patients, AASI and Sym-AASI were higher (P < 0.001) than in normotensive subjects, but both indices of vascular stiffness were comparable in patients with and without NAFLD.ConclusionsIn essential hypertensive patients without additional cardiovascular risk factors, NAFLD is associated with insulin resistance but not with increased arterial stiffness. 相似文献