全文获取类型
收费全文 | 217030篇 |
免费 | 3149篇 |
国内免费 | 366篇 |
专业分类
耳鼻咽喉 | 1571篇 |
儿科学 | 7392篇 |
妇产科学 | 4239篇 |
基础医学 | 21506篇 |
口腔科学 | 3213篇 |
临床医学 | 15543篇 |
内科学 | 42633篇 |
皮肤病学 | 1572篇 |
神经病学 | 20087篇 |
特种医学 | 9947篇 |
外科学 | 35117篇 |
综合类 | 2467篇 |
一般理论 | 9篇 |
预防医学 | 20290篇 |
眼科学 | 3407篇 |
药学 | 11717篇 |
中国医学 | 737篇 |
肿瘤学 | 19098篇 |
出版年
2023年 | 299篇 |
2022年 | 421篇 |
2021年 | 1464篇 |
2020年 | 791篇 |
2019年 | 1130篇 |
2018年 | 23228篇 |
2017年 | 18184篇 |
2016年 | 20412篇 |
2015年 | 2165篇 |
2014年 | 2541篇 |
2013年 | 3046篇 |
2012年 | 10415篇 |
2011年 | 24282篇 |
2010年 | 20620篇 |
2009年 | 13096篇 |
2008年 | 22277篇 |
2007年 | 24543篇 |
2006年 | 3385篇 |
2005年 | 4980篇 |
2004年 | 5894篇 |
2003年 | 6590篇 |
2002年 | 4472篇 |
2001年 | 523篇 |
2000年 | 578篇 |
1999年 | 436篇 |
1998年 | 556篇 |
1997年 | 517篇 |
1996年 | 364篇 |
1995年 | 374篇 |
1994年 | 311篇 |
1993年 | 219篇 |
1992年 | 175篇 |
1991年 | 181篇 |
1990年 | 217篇 |
1989年 | 157篇 |
1988年 | 115篇 |
1987年 | 95篇 |
1986年 | 95篇 |
1985年 | 98篇 |
1984年 | 91篇 |
1983年 | 85篇 |
1982年 | 118篇 |
1981年 | 62篇 |
1980年 | 107篇 |
1978年 | 56篇 |
1976年 | 43篇 |
1974年 | 47篇 |
1938年 | 63篇 |
1932年 | 59篇 |
1930年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
51.
Carmelo Tassi Antonio Angelini Tommaso Beccari Enrico Capodicasa 《Clinical chemistry and laboratory medicine》2006,44(7):843-847
BACKGROUND: The activity and isoenzyme composition of N-acetyl-beta-D-hexosaminidase (EC.3.2.1.52) in seminal plasma of fertile and infertile men have been evaluated. However, no data are available on the isoenzyme content in seminal plasma from patients with secretory azoospermia. METHODS: The activity and isoenzyme composition of seminal plasma from 15 normozoospermic controls and 18 patients with secretory azoospermia were determined by fluorimetric methods. 4-Methylumbelliferil-2-acetamido-2-deoxy-beta-D-glucopyranoside and 4-methylumbelliferil-2-acetamido-2-deoxy-beta-D-glucopyranoside-6-sulfate were used as fluorigenic substrates. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficiency of the assays. RESULTS: No significant difference was found in total enzyme activity between the two groups, while isoenzyme A activity was significantly lower (p=0.004) and the ratio between total enzyme activity and isoenzyme A activity was significantly higher (p=0.04) in azoospermic patients compared to controls. The diagnostic efficiency of these evaluations was low (< or =75.7%). CONCLUSIONS: Our findings show that the isoenzyme composition of N-acetyl-beta-D-hexosaminidase in seminal plasma from patients with secretory azoospermia is significantly different from controls, but this difference does not represent a useful marker of secretory azoospermia. The fluorimetric assays are simple and rapid methods for evaluating the isoenzyme composition. 相似文献
52.
Jesús Hermida J Antonio Casal J Carlos Tutor 《Clinical chemistry and laboratory medicine》2003,41(3):302-305
Using 3,3'-diclorophenolsulfoftaleinil N-acetyl-beta-D-glucosaminide as a substrate, the apparent activation energy of beta-N-acetylhexosaminidase (Hex) was determined in samples of plasma and urine, as well as in leukocyte and platelet lysates. Incubation with papain produced an increase in this thermodynamic variable for plasma Hex (precursor forms with high molecular mass) that would be caused by the proteolytic action of papain on the Hex A isoenzyme. However, digestion with papain did not significantly modify the activation energy of Hex in leukocyte and platelet lysates (mature enzymatic forms). In 11 healthy subjects and 28 patients with different renal diseases, no statistically significant differences were found with regard to the values obtained in cellular lysates for variations in the activation energy of urinary Hex, regardless of whether they presented normoalbuminuria, microalbuminuria or macroalbuminuria. These results support the hypothesis that even in patients with proteinuria, no significant amounts of plasma Hex precursor forms are found in urine samples, and the source of the enzyme activity is the kidney itself. 相似文献
53.
54.
Susanne Ramsauer 《Zeitschrift für Psychodrama und Soziometrie》2007,6(2):293-302
Anliegen dieses Artikels ist, die besondere Qualit?t und Chance von Psychodramatischer Supervision zu beschreiben, und gleichzeitig
die Kompatibilit?t und fruchtbare Erg?nzung des Moreno’schen Ansatzes innerhalb des Formats Supervision innerhalb der Sozialen
Arbeit auf zuzeigen. Dies wird anhand von 2 ausgew?hlten Praxisbeispielen dargestellt. Die Handlungskompetenz von Supervisandinnen
und Supervisanden kann durch einfache psychodramatische Interventionen erweitert werden. Handlungshemmung wird überwunden,
Spontaneit?t und Kreativit?t kommen ins Laufen und er?ffnen Perspektiven. 相似文献
55.
56.
Debra L. Roter Richard M. Frankel Judith A. Hall David Sluyter 《Journal of general internal medicine》2006,21(1):28-34
Relationship-centered care reflects both knowing and feeling: the knowledge that physician and patient bring from their respective domains of expertise, and the physician’s and patient’s experience, expression, and perception of emotions during the medical encounter. These processes are conveyed and reciprocated in the care process through verbal and nonverbal communication. We suggest that the emotional context of care is especially related to nonverbal communication and that emotion-related communication skills, including sending and receiving nonverbal messages and emotional self-awareness, are critical elements of high-quality care. Although nonverbal behavior has received far less study than other care processes, the current review argues that it holds significance for the therapeutic relationship and influences important outcomes including satisfaction, adherence, and clinical outcomes of care. 相似文献
57.
Raoul Orvieto Irina Zagatsky Vered Yulzari-Roll Antonio La Marca Benjamin Fisch 《Gynecological endocrinology》2006,22(8):437-440
BACKGROUND: To investigate the degree of systemic inflammation, as reflected by serum C-reactive protein (CRP) levels, associated with controlled ovarian hyperstimulation (COH) with human chorionic gonadotropin (hCG) or gonadotropin-releasing hormone (GnRH) agonist for the induction of final follicular maturation. DESIGN: Prospective, observational study. SETTING: An in vitro fertilization (IVF) unit of an academic medical center. PATIENTS: Twenty-four women undergoing COH and IVF with the flexible GnRH antagonist protocol were prospectively assigned to receive hCG or GnRH agonist for the induction of final follicular maturation. METHODS: Blood was drawn three times during COH for measurement of sex-steroid and CRP levels: the day on which adequate suppression was obtained (Day-0); the day of or prior to administration of hCG (Day-hCG); and (3) the day of ovum pick-up (Day-OPU). Levels were compared among the three time points in the two groups. RESULTS: No between-group differences were observed in terms of patient age, gonadotropin dosage, duration of stimulation or number of oocytes retrieved. Serum CRP levels were significantly higher on Day-OPU than on Day-hCG and Day-0, but the difference was significant only in the hCG group (p<0.03 for both). The percentage change in CRP levels after hCG administration (Day-OPU vs. Day-hCG) (96%) was higher than that after GnRH administration (23%). CONCLUSION: Administration of GnRH agonist in patients undergoing COH for IVF yields a lesser degree of systemic inflammation, as reflected by CRP levels, than hCG. 相似文献
58.
Caterina Proto Daniela Romualdi Rosa Maria Cento Rosario S Spada Giuseppina Di Mento Raffaele Ferri Antonio Lanzone 《Gynecological endocrinology》2006,22(4):213-218
BACKGROUND: In the central nervous system, several neuropeptides are believed to be involved in the pathophysiology of Alzheimer's disease (AD). Indeed, previous studies have documented that glucagon-like peptide 1 (GLP-1) possesses neurotropic properties and can reduce amyloid-beta peptide levels in the brain in vivo. Moreover, the concentrations of neuropeptide Y (NPY) seem to be altered in the cerebrospinal fluid of patients with AD and in subjects with major depression. Finally, among the modifications induced by aging, a dysregulation of the ghrelin-growth hormone (GH) system has been reported. METHODS: We investigated the plasma concentrations of these neuropeptides in 14 subjects with AD. Data obtained from these patients were compared with data from an age- and weight-matched healthy group. RESULTS: No significant differences were found between the two groups in relation to plasma levels of GLP-1, NPY, ghrelin and GH. Peripheral NPY concentrations were positively correlated with ghrelin levels in both groups, and with plasma GLP-1 concentration only in controls. CONCLUSION: On the basis of our results, peripheral levels of these neuropeptides seem not to serve as biochemical markers of AD. 相似文献
59.
Bruno Ferrari Antonio Pezzuto Lorenzo Barusi Francesco Coppola 《Gynecological endocrinology》2006,22(6):289-296
The aim of the present study was to investigate the effect of gonadotropin-releasing hormone (GnRH) antagonists (GnRH-ant) on follicular fluid (FF) insulin-like growth factor-I (IGF-I) and FF vascular endothelial growth factor (VEGF) levels. Sixty women undergoing assisted reproduction were randomized and assigned to two different GnRH analog regimens: GnRH agonist (GnRH-a) and GnRH-ant. FF VEGF and FF IGF-I concentrations were significantly increased in the patients treated with GnRH-ant (p < 0.001). In the same patients we observed a statistically significant reduction in serum luteinizing hormone (LH) and estradiol (E2) levels (p < 0.001 and p < 0.05, respectively), FF E2 and FF androstenedione levels (p < 0.05 and p < 0.001, respectively), as well as a reduction in the number of pregnancies although this was not statistically significant. In the GnRH-ant group, FF VEGF levels were positively correlated with FF IGF-I levels, and both were negatively correlated with serum LH levels. The increase in FF IGF-I and FF VEGF levels in women treated with GnRH-ant could be explained by a deleterious follicular environment in response to profound suppression of LH and E2 levels. 相似文献
60.
Indices of surgical site infection risk and prediction of other adverse outcomes during hospitalization. 总被引:2,自引:0,他引:2
Miguel Delgado-Rodríguez Silvia Palma Antonio Gómez-Ortega Gabriel Martínez-Gallego Marcelino Medina-Cuadros 《Infection control and hospital epidemiology》2006,27(8):825-828
OBJECTIVE: To assess which adverse postsurgical outcomes are best predicted by the Study on the Efficacy of Nosocomial Infection Control (SENIC) index and the National Nosocomial Infection Surveillance system (NNIS) index. DESIGN: Prospective cohort study. SETTING: The service of general surgery at a tertiary care hospital. PATIENTS: A consecutive series of patients hospitalized for more than 1 day (n=2,989). RESULTS: The outcome best predicted by the SENIC and NNIS indices was assessed by estimating the area under the receiver operating characteristic (ROC) curve. The areas under the ROC curves for nosocomial infection and in-hospital death were higher for the NNIS index than they were for the SENIC index (P<.05). The NNIS index predicted in-hospital death better than it predicted surgical site infection (area under the ROC curve+/-SE, 0.836+/-0.022 vs 0.689+/-0.017; P=.001). CONCLUSIONS: The NNIS index is superior to the SENIC index for all adverse postsurgical outcomes. Its ability to predict in-hospital mortality is clearly better than its ability to predict surgical site infection. 相似文献