全文获取类型
收费全文 | 11268篇 |
免费 | 689篇 |
国内免费 | 68篇 |
专业分类
耳鼻咽喉 | 123篇 |
儿科学 | 341篇 |
妇产科学 | 206篇 |
基础医学 | 1253篇 |
口腔科学 | 450篇 |
临床医学 | 845篇 |
内科学 | 3237篇 |
皮肤病学 | 205篇 |
神经病学 | 1016篇 |
特种医学 | 333篇 |
外科学 | 1483篇 |
综合类 | 33篇 |
一般理论 | 1篇 |
预防医学 | 457篇 |
眼科学 | 140篇 |
药学 | 878篇 |
中国医学 | 21篇 |
肿瘤学 | 1003篇 |
出版年
2023年 | 92篇 |
2022年 | 216篇 |
2021年 | 420篇 |
2020年 | 216篇 |
2019年 | 337篇 |
2018年 | 389篇 |
2017年 | 282篇 |
2016年 | 354篇 |
2015年 | 366篇 |
2014年 | 461篇 |
2013年 | 608篇 |
2012年 | 794篇 |
2011年 | 787篇 |
2010年 | 431篇 |
2009年 | 384篇 |
2008年 | 625篇 |
2007年 | 643篇 |
2006年 | 637篇 |
2005年 | 585篇 |
2004年 | 521篇 |
2003年 | 408篇 |
2002年 | 396篇 |
2001年 | 193篇 |
2000年 | 190篇 |
1999年 | 187篇 |
1998年 | 79篇 |
1997年 | 71篇 |
1996年 | 58篇 |
1995年 | 66篇 |
1994年 | 54篇 |
1993年 | 44篇 |
1992年 | 122篇 |
1991年 | 78篇 |
1990年 | 88篇 |
1989年 | 83篇 |
1988年 | 76篇 |
1987年 | 77篇 |
1986年 | 64篇 |
1985年 | 67篇 |
1984年 | 56篇 |
1983年 | 67篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 18篇 |
1979年 | 34篇 |
1978年 | 24篇 |
1976年 | 19篇 |
1975年 | 31篇 |
1974年 | 29篇 |
1970年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Calogera Pisano Daniele Polisano Carmela Rita Balistreri Claudia Altieri Paolo Nardi Fabio Bertoldo Daniele Trombetti Laura Asta Maria Sabrina Ferrante Dario Buioni Calogero Foti Giovanni Ruvolo 《Nutrients》2021,13(2)
Frailty is the major expression of accelerated aging and describes a decreased resistance to stressors, and consequently an increased vulnerability to additional diseases in elderly people. The vascular aging related to frail phenotype reflects the high susceptibility for cardiovascular diseases and negative postoperative outcomes after cardiac surgery. Sarcopenia can be considered a biological substrate of physical frailty. Malnutrition and physical inactivity play a key role in the pathogenesis of sarcopenia. We searched on Medline (PubMed) and Scopus for relevant literature published over the last 10 years and analyzed the strong correlation between frailty, sarcopenia and cardiovascular diseases in elderly patient. In our opinion, a right food intake and moderate intensity resistance exercise are mandatory in order to better prepare patients undergoing cardiac operation. 相似文献
32.
Carlo Giulioni Valentina Maurizi Simone Scarcella Manuel Di Biase Valerio Iacovelli Andrea Benedetto Galosi Daniele Castellani 《Andrologia》2021,53(11):e14215
Our purpose was to review and analyse the impact of pyrethroids and organophosphates exposure on human semen parameters. A comprehensive literature search was performed through MEDLINE via PubMed, Scopus and Webscience. Only cohort studies examining semen parameters in workers or general populations exposed to pyrethroids or organophosphates were included. Ejaculate volume, sperm count, concentration, motility, viability, normal morphology and seminal pH alterations were pooled using the Cochran–Mantel–Haenszel Method with the random effect model and expressed as weighted mean difference, risk ratios, 95% confidence intervals and p-values. Seven cross-sectional studies regarding pyrethroids were included. Four of them were eligible for meta-analysis. The only parameter affected by pyrethroid exposure was normal sperm morphology (WMD-7,61%, 95%CI –11,92 to −3,30;p = 0,0,005). Nine studies were selected to evaluate the impact of organophosphates on semen parameters with six of them eligible for meta-analysis. A significant reduction was detected for the following: ejaculate volume (WMD −0,47ml, 95%CI −0,69 to −0,25; p < 0,0001), sperm count (WMD-40,03, 95%CI −66,81 to −13,25;p = 0,003), concentration (WMD-13,69 x10⁶/mL, 95%CI −23, 27 to-4,12;p = 0,005) and motility (WMD −5,70%, 95%CI −12,89 to 1,50;p = 0,12). Despite the increase in sperm abnormality, it has been shown that pyrethroids are unrelated to reduced sperm quality. However, the negative association of organophosphates with spermatogenesis is noteworthy. 相似文献
33.
Michael Indermaur Daniele Casari Tatiana Kochetkova Cinzia Peruzzi Elizabeth Zimmermann Frank Rauch Bettina Willie Johann Michler Jakob Schwiedrzik Philippe Zysset 《Journal of bone and mineral research》2021,36(7):1364-1375
Osteogenesis imperfecta (OI) is an inheritable, genetic, and collagen-related disorder leading to an increase in bone fragility, but the origin of its “brittle behavior” is unclear. Because of its complex hierarchical structure, bone behaves differently at various length scales. This study aims to compare mechanical properties of human OI bone with healthy control bone at the extracellular matrix (ECM) level and to quantify the influence of the degree of mineralization. Degree of mineralization and mechanical properties were analyzed under dry conditions in 12 fixed and embedded transiliac crest biopsies (control n = 6, OI type I n = 3, OI type IV n = 2, and OI type III n = 1). Mean degree of mineralization was measured by microcomputed tomography at the biopsy level and the mineral-to-matrix ratio was assessed by Raman spectroscopy at the ECM level. Both methods revealed that the degree of mineralization is higher for OI bone compared with healthy control. Micropillar compression is a novel technique for quantifying post-yield properties of bone at the ECM level. Micropillars (d = 5 μm, h = 10 μm) were fabricated using focused ion beam milling and quasi-statically compressed to capture key post-yield properties such as ultimate strength. The qualitative inspection of the stress–strain curves showed that both OI and healthy control bone have a ductile response at the ECM level. The quantitative results showed that compressive strength is not reduced in OI bone and is increasing with OI severity. Nanoindentation measurements revealed that OI bone tends to have a higher Young's modulus, hardness, and dissipated energy compared with healthy bone. Micropillar strength and indentation modulus increased linearly and significantly (p < .0001) with mineral-to-matrix ratio. In conclusion, this study indicates that compressive mechanical properties of dry OI bone at the iliac crest are not inferior to healthy control at the ECM level and increase with mineralization. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). 相似文献
34.
Patrick S. Powell Karen Pazol Lisa D. Wiggins Julie L. Daniels Gabriel S. Dichter Chyrise B. Bradley Rebecca Pretzel Joy Kloetzer Charmaine McKenzie Alexys Scott Britney Robinson Amy S. Sims Eric P. Kasten M. Daniele Fallin Susan E. Levy Patricia M. Dietz Mary E. Cogswell 《MMWR. Morbidity and mortality weekly report》2021,70(17):605
35.
Zoledronic acid-related angiogenesis modifications and survival in advanced breast cancer patients. 总被引:5,自引:0,他引:5
Bruno Vincenzi Daniele Santini Giordano Dicuonzo Fabrizio Battistoni Michele Gavasci Annalisa La Cesa Claudia Grilli Vladimir Virzì Simona Gasparro Laura Rocci Giuseppe Tonini 《Journal of interferon & cytokine research》2005,25(3):144-151
The proven antiangiogenic activity of zoledronic acid, a third-generation bisphosphonate widely used in bone metastatic cancer patients, led us to investigate if the vascular endothelial growth factor (VEGF)-related zoledronic acid modifications are correlated with survival advantages in advanced breast cancer patients. Forty-two consecutive breast cancer patients with scintigraphic and radiographic evidence of bone metastases were treated with a single infusion of 4 mg zoledronic acid before anticancer chemotherapy. The patients were prospectively evaluated for circulating levels of VEGF and interferon-gamma (IFN-gamma) just before and at 1, 2, 7, and 21 days after zoledronic acid infusion. Afterward, clinical outcome was prospectively monitored. The basal serum VEGF median levels were significantly decreased at each time point, but the major reduction was recorded 21 days after the infusion. In particular, 25 patients of 42 (59.5%) experienced a reduction of at least 25% in the VEGF circulating levels. In contrast, no statistically significant modifications of the IFN-gamma serum levels were recorded. We stratified patients on the basis of this VEGF reduction 21 days after the infusion. No differences in patient features were recorded between those with or without the VEGF reduction. The analysis of survival showed that patients with a reduction in the VEGF circulating levels had a longer time to first skeletal-related event (p = 0.0002), time to bone progression disease (p = 0.0024), and time to performance status worsening (p = 0.0352) than those without the VEGF reduction. No statistically significant differences were recorded in terms of overall survival and time to visceral progression. This study confirms that zoledronic acid could have an in vivo antiangiogenic property and that the VEGF modifications may represent a surrogate marker able to predict time to first skeletal-related event, time to bone progression disease, and time to worsening of performance status. 相似文献
36.
In vitro and in vivo effects of cisplatin on the generation of lymphokine-activated killer cells 总被引:1,自引:0,他引:1
P Allavena P Pirovano C Bonazzi N Colombo A Mantovani M D'Incalci 《Journal of the National Cancer Institute》1990,82(2):139-142
Pretreatment of human peripheral blood lymphocytes (PBL) with cisplatin (CDDP) before in vitro culture with interleukin-2 (IL-2) inhibited the generation of lymphokine-activated killer (LAK) cells and strongly inhibited proliferation. This inhibition was dose dependent, was significant only at concentrations greater than 6 microM, and it required exposure to the drug for more than 1 hour. This period of IL-2 unresponsiveness was maximum at 6 hours, but was spontaneously recovered within 24-48 hours and was more rapidly restored by increasing dosages of IL-2. Because inhibition of the generation of LAK cells by CDDP was observed only at relatively high levels of exposure to the drug (greater than 6 microM for greater than 1 hr), it was important that we explore the in vivo significance of these findings. The peripheral blood lymphocytes from patients bearing ovarian adenocarcinoma collected 1 hour after an iv infusion of 50 mg of CDDP/m2 were not inhibited, compared with those collected immediately before therapy. Relatively high levels of exposure to CDDP are required for inhibition of the generation of new cytotoxic effectors, most likely because of its antiproliferative effect. These results may bear relevance to approaches involving the combined use of CDDP and IL-2-LAK. 相似文献
37.
38.
Friedman D Cuneo S Valenzano M Marinari GM Adami GF Gianetta E Traverso E Scopinaro N 《Obesity surgery》1995,5(3):308-313
Background: 239 pregnancies occurred in 1136 women who had undergone biliopancreatic diversion (BPD). Methods: There were
73 abortions, and 14 pregnancies are presently in their course. The 152 term pregnancies (six twins) occurred in 129 women
2-173 months (mean 42.7) after BPD. Mean age and current excess weight were 31.4 years (20-42) and 29.1% (-6.9-78.2), and
mean excess weight loss was 72.9% (30.4-110.5). Results: Mean weight gain during pregnancy was 6.2 kg (-21-25). In 32 patients
(21%), parenteral nutritional support was needed. In all the other patients (79%), the usual supplementations were given.
Of the newborns, 122 were delivered at term (84.7%) with a mean weight of 2842.4 g (1760-4600 g) and a mean length of 48.5
cm (43-59 cm), while the 22 preterm babies (15.3%) weighed 2151.1 g (1400-3850 g) and had a length of 44.6 cm (33-56 cm).
Forty infants (27.8%) were small for gestational age but 17 of them weighed more than 2500 g. Eleven twins (one abortion at
26th week) were also delivered, with a mean weight of 2088.6 g (1200-3100 g) and a mean length of 45.6 cm (35-50 cm). Delivery
was spontaneous in 85 instances (56%), while vacuum extractor was used in one, and 66 cesarean sections were performed. There
were two birth malformations, one infant died after surgery for meconium obstruction and two died from unknown causes. Of
the 129 women, 35 had been infertile before BPD. Conclusions: Disappearance of infertility and decrease of pregnancy risk
are to be considered among the beneficial effects of weight reduction following BPD. 相似文献
39.
p53 Accumulation Is a Prognostic Factor in Intestinal-Type Gastric Carcinoma but Not in the Diffuse Type 总被引:2,自引:0,他引:2
Roviello F Marrelli D Vindigni C De Stefano A Spina D Pinto E 《Annals of surgical oncology》1999,6(8):739-745
Background: The prognostic value of p53 nuclear accumulation in gastric cancer is still unclear, as shown by the discordant results still reported in the literature. In this study, we evaluated the correlation between p53 accumulation and long-term survival of patients resected for intestinal and diffuse-type gastric cancer.Methods: Eighty-three patients with carcinoma of the intestinal type and 53 patients with carcinoma of the diffuse type were included in the study. Immunohistochemical staining of the paraffin sections was performed by using monoclonal antibody DO1; cases were considered positive when nuclear immunostaining was observed in 10% or more of the tumor cells. Prognostic significance of different variables was investigated by univariate and multivariate analysis.Results: p53 positivity was found in 51.8% of intestinal-type and 50.9% of diffuse-type cases. No significant correlation between the rate of p53 overexpression and age, sex, tumor location, tumor size, depth of invasion, lymph node involvement, distant metastases, and surgical radicality was found in the two groups of patients. A statistically significant difference in survival rate was observed between p53-negative and p53-positive cases in the intestinal type (P < .05), confirmed by multivariate analysis (P < .005; relative risk = 3.09). On the contrary, no correlation with survival was found in diffuse-type cases according to p53 overexpression.Conclusions: These results suggest that the immunohistochemical detection of p53 accumulation is a useful indicator of poor prognosis in the intestinal but not in the diffuse type of gastric cancer, and are indicative of distinct molecular pathways and pattern of progression in the two histotypes. 相似文献
40.
Long, interlaminar, astroglial processes and its patterned organization in the striate cortex of adult primates was previously described. Loss of visual input following bilateral retinal detachment and degeneration in an adult Cebus apella monkey resulted three months later in reduction of interlaminar processes immunoreactive to Glial Fibrillary Acid Protein antibody, loss of the honeycomb-like pattern normally present in tangential sections, and loss of high density patches of terminal segments of those processes in the opercular striate. These results further indicate the highly interactive nature of neuron-glial cerebral cortex architecture, and the dynamic regulation of astroglial interlaminar processes. 相似文献