全文获取类型
收费全文 | 6720篇 |
免费 | 328篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 168篇 |
妇产科学 | 127篇 |
基础医学 | 768篇 |
口腔科学 | 300篇 |
临床医学 | 466篇 |
内科学 | 1483篇 |
皮肤病学 | 201篇 |
神经病学 | 619篇 |
特种医学 | 115篇 |
外科学 | 1099篇 |
综合类 | 34篇 |
一般理论 | 1篇 |
预防医学 | 616篇 |
眼科学 | 199篇 |
药学 | 345篇 |
中国医学 | 58篇 |
肿瘤学 | 376篇 |
出版年
2023年 | 44篇 |
2022年 | 85篇 |
2021年 | 233篇 |
2020年 | 127篇 |
2019年 | 176篇 |
2018年 | 228篇 |
2017年 | 128篇 |
2016年 | 153篇 |
2015年 | 178篇 |
2014年 | 265篇 |
2013年 | 307篇 |
2012年 | 559篇 |
2011年 | 534篇 |
2010年 | 313篇 |
2009年 | 286篇 |
2008年 | 462篇 |
2007年 | 518篇 |
2006年 | 418篇 |
2005年 | 433篇 |
2004年 | 387篇 |
2003年 | 343篇 |
2002年 | 340篇 |
2001年 | 46篇 |
2000年 | 35篇 |
1999年 | 47篇 |
1998年 | 45篇 |
1997年 | 30篇 |
1996年 | 30篇 |
1995年 | 27篇 |
1994年 | 16篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 18篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 15篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1975年 | 9篇 |
1974年 | 5篇 |
排序方式: 共有7071条查询结果,搜索用时 125 毫秒
21.
Feng-Chun Tsai Daniel Marelli Jessica Bresson David Gjertson Reza Kermani Abbas Ardehali Fardad Esmailian Michele Hamilton Gregg C Fonarow Jaime Moriguchi Mark Plunkett Antoine Hage Julie Tran Jon A Kobashigawa Hillel Laks 《American journal of transplantation》2002,2(6):539-545
Older age, prior transplantation, pulmonary hypertension, and mechanical support are commonly seen in current potential cardiac transplant recipients. Transplants in 436 consecutive adult patients from 1994 to 1999 were reviewed. There were 251 using standard donors in 243 patients (age range 18-69 years). To emphasize recipient risk, 185 patients who received a nonstandard donor were excluded from analysis. The indications for transplant were ischemic heart disease (n = 123, 47%), dilated cardiomyopathy (n = 82, 32%), and others (n=56, 21%). One hundred and forty-nine (57%) recipients were listed as status I; 5 and 6% were supported with an intra-aortic balloon and an assist device, respectively. The 30-d survival and survival to discharge were 94.7 and 92.7%, respectively; 1-year survival was 89.1%. Causes of early death were graft failure (n = 6), infection (n = 4), stroke (n = 4), multiorgan failure (n = 3) and rejection (n = 2). Predictors were balloon pump use alone (OR= 11.4, p =0.002), pulmonary vascular resistance > 4 Wood units (OR = 5.7, p = 0.007), pretransplant creatinine > 2.0 mg/dL (OR = 6.9, p = 0.004) and female donor (OR = 8.3, p = 0.002). Recipient age and previous surgery did not affect short-term survival. Heart transplantation in the current era consistently offers excellent early and 1-year survival for well-selected recipients receiving standard donors. Early mortality tends to reflect graft failure while hospital mortality may be more indicative of recipient selection. 相似文献
22.
Summary A two-cell human embryo recovered from the Fallopian tube 82 h following the LH peak in plasma and 37 h after a single episode of intercourse was examined by transmission electron microscopy. At the time of recovery the embryo was denuded of cumulus cells, and both the zona pellucida and the two adjoining blastomeres were intact. The finding of two polar bodies in the perivitelline space, two nucleated blastomeres and remnants of the fertilizing sperm tail within the cytoplasm of one of them, were considered as evidences that the embryo was normally fertilized. Among the most compicuous features found were the presence of very distinct desmosome-like structure between blastomeres, and the cytoplasmic cell organelles distribution in three areas referred as: a sub-cortical, a middle and a perinuclear bands. An outstanding feature was the extensive blebbing of the nuclear envelope. In general, the features seem to correspond to a normally developing two-cell embryo undergoing cleavage at a normal rate. 相似文献
23.
Summary: Purpose: Sphenoidal electrode (SE) insertion can cause pain, for which local anesthesia with lidocaine or intravenous administration of fentanyl has been advocated by different epilepsy treatment centers. Transient facial palsies have been observed after SE insertion. Their frequency of occurrence, distribution, and duration have not been well characterized, however. We hypothesized that this complication is due to the effect of local anesthesia on the peripheral branches of the seventh cranial nerve. To test this hypothesis, we compared the incidence and characteristics of facial palsy during SE insertions performed with either local anesthesia or after intravenous fentanyl administration.
Methods: We performed a retrospective study in two patient groups. Group A consisted of 25 patients aged 28 ± 8·2 years who underwent a prolonged video-EEG (VEEG) monitoring study with SE after subcutaneous infusion of 1% lidocaine in the insertion area. Group B included 25 patients aged 30·1 ± 8·9 years whose SE were inserted after intravenous administration of 100-200 μ fentanyl. Blood pressure (BP) was monitored every 3-5 min throughout the procedure.
Results: Five patients (20%) from group A had a transient facial palsy; in 4, it was complete and in 1 it was partial; 1 patient had a bilateral facial palsy. Paresis lasted 1-7 min (mean 3·2 min). In all patients, the recovery was complete. None of the patients in group B had complications (p = 0·025, Fisher's exact test).
Conclusions: Transient facial palsy is a relatively frequent complication of SE insertion when SE are placed under local anesthesia; patients should be forewarned of its possible occurrence. 相似文献
Methods: We performed a retrospective study in two patient groups. Group A consisted of 25 patients aged 28 ± 8·2 years who underwent a prolonged video-EEG (VEEG) monitoring study with SE after subcutaneous infusion of 1% lidocaine in the insertion area. Group B included 25 patients aged 30·1 ± 8·9 years whose SE were inserted after intravenous administration of 100-200 μ fentanyl. Blood pressure (BP) was monitored every 3-5 min throughout the procedure.
Results: Five patients (20%) from group A had a transient facial palsy; in 4, it was complete and in 1 it was partial; 1 patient had a bilateral facial palsy. Paresis lasted 1-7 min (mean 3·2 min). In all patients, the recovery was complete. None of the patients in group B had complications (p = 0·025, Fisher's exact test).
Conclusions: Transient facial palsy is a relatively frequent complication of SE insertion when SE are placed under local anesthesia; patients should be forewarned of its possible occurrence. 相似文献
24.
The DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) procedure was used to analyze DNA single-strand breaks (SSBs) and alkali-labile sites induced by exposure to the nitric oxide (NO) donors sodium nitroprusside (SNP) and 3-morpholinosydnomine hydrochloride (SIN-1) in the whole genome and in long interstitial telomeric repeat sequence (ITRS) blocks from Chinese hamster cells. The relative density of DNA damage generated in the ITRS by X-rays was similar to that induced in the genome overall, whereas it was 1.7 times higher when the alkylating agent MNNG was assayed. Nevertheless, after SNP or SIN-1 treatment, ITRSs proved to be 2.8 and 2.7 times relatively more damaged, respectively, than the whole genome. When the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) was not active, as in XR-C1 mutant cells, the repair kinetics in the whole genome did not differ from that in the parental cell line with X-ray or SNP exposure. However, whereas the SSBs and alkali-labile sites induced in the ITRS by X-rays exhibited rejoining kinetics similar to that of the parental cell line, the damage induced by SNP was more slowly rejoined. This implies a role for DNA-PKcs in the repair of DNA damage induced by NO, especially in ITRSs. The results demonstrated intragenomic heterogeneity of NO-induced DNA damage and repair; there was a higher density of DNA damage in the ITRS blocks, possibly because of their guanine richness. This suggests that a parallel process may occur in the terminal telomeres, which has implications for premature aging and neoplastic development by chronic NO exposure in vivo. 相似文献
25.
Dendritic cells (DCs) constitute the link between innate and adaptive immunity by directly recognizing pathogen-associated molecular patterns (PAMPs) on bacteria and by processing and presenting bacterial antigens to T cells. Recognition of PAMPs renders DCs as professional antigen-presenting cells with the ability to prime naive T cells and to initiate the adaptive immune response against pathogen-derived antigens. For this reason, any interference with DC function might be advantageous for bacterial survival and dissemination. Identification of the molecular interactions occurring between DCs and bacterial pathogens is necessary to understand the mechanisms that virulent bacteria have evolved to prevent recognition by the adaptive immune system. This could be helpful in the identification of possible new targets that might lead to the design of effective therapies aimed at preventing or treating serious infections by these pathogens. In this article, we focus on Salmonella enterica serovar Typhimurium, the causative agent of typhoid-like disease in the mouse, and how it is able to escape from DC-mediated antigen presentation by avoiding lysosomal degradation. This feature of virulent Salmonella requires the functional expression of the Type Three Secretion System (TTSS) and effector proteins encoded within the Salmonella pathogenicity island 2 (SPI-2). Recent studies have demonstrated that impairment of DC function by the activity of SPI-2 gene products is crucial for Salmonella pathogenesis. 相似文献
26.
27.
Resino S Rivero L Ruiz-Mateos E Galán I Franco JM Munoz-Fernández MA Leal M 《Journal of clinical immunology》2004,24(4):379-388
We evaluated phenotypic and functional parameters of immune restoration of 27 HIV-infected patients on highly active antiretroviral therapy (HAART) (HIV-cases) with HIV-RNA levels below detectable limits at least during 18 months, and CD4+ cell per microliter higher than 500 at the moment of the study and lower than 300 anytime before. These patients were compared with 11 HIV-controls that never had less than 500 CD4+ cell per microliter and 20 healthy-controls (HIV seronegative subjects) in a cross-sectional study. HIV-cases had lower counts of naïve CD4+ than HIV-controls and healthy-controls. HIV-patients (both HIV-cases and HIV-controls) showed higher values of naïve and memory CD8+ counts than healthy-controls. TREC-bearing cell levels were significantly lower in HIV-cases than in healthy-controls. Peripheral blood mononuclear cells (PBMC) cultures, HIV-cases had lower values in proliferation to streptokinase (SK) and tetanus toxin (TT) than in healthy-controls. HIV-cases had lower IFN-γ and higher IL-5 production with pokeweed than healthy-controls (P < 0.01). However, IL-5 production of HIV-cases after TT stimulation was lower than in HIV-controls and healthy-controls. Total IgG and IgG1 levels were significantly higher in HIV-cases than in HIV-controls and healthy-controls. Also, IgM levels were significantly higher in HIV-cases than in healthy-controls. Nevertheless, IgG2 levels were significantly lower in HIV-cases and HIV-controls than in healthy-controls. The levels of specific Igs antipneumococcal capsular polysaccharide and TT were significantly lower in HIV-cases than in healthy-controls. HIV-patients with a previous state of severe-moderate immunosuppression normalizing their CD4+ counts have a incomplete immune reconstitution after HAART. Long-term consequences of this subclinical immune deficiency remain to be determined. 相似文献
28.
29.
Ruiter DJ Roald B Underwood J Prat J;UEMS Section of Pathology/European Board of Pathology 《Virchows Archiv : an international journal of pathology》2004,444(3):278-282
Critical shortages of trained histopathologists limit the capacity of cancer and other clinical services. A survey of histopathology training in 18 European countries conducted by the European Union of Medical Specialists Section of Pathology/European Board of Pathology revealed a considerable shortage of both trained and trainee histopathologists in several of the responding countries. Demographic data indicate a high preponderance of trained histopathologists over 55 years of age and a notable proportion of part-time personnel. Although the training capacity in some countries has been increased, the immediate future of histopathology and the clinical services dependent on the specialty is worrisome. The histopathology workload is growing, and, in some countries, recruitment of trainees is insufficient for future needs. To avert the serious consequences for dependent clinical specialties and their patients, there should be a concerted European action to promote and expand histopathology training. 相似文献
30.