全文获取类型
收费全文 | 805篇 |
免费 | 39篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 55篇 |
妇产科学 | 13篇 |
基础医学 | 74篇 |
口腔科学 | 11篇 |
临床医学 | 76篇 |
内科学 | 216篇 |
皮肤病学 | 21篇 |
神经病学 | 6篇 |
特种医学 | 139篇 |
外科学 | 150篇 |
综合类 | 9篇 |
预防医学 | 24篇 |
眼科学 | 4篇 |
药学 | 22篇 |
肿瘤学 | 27篇 |
出版年
2022年 | 7篇 |
2021年 | 21篇 |
2020年 | 2篇 |
2019年 | 9篇 |
2018年 | 19篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 18篇 |
2014年 | 21篇 |
2013年 | 29篇 |
2012年 | 23篇 |
2011年 | 19篇 |
2010年 | 32篇 |
2009年 | 24篇 |
2008年 | 19篇 |
2007年 | 14篇 |
2006年 | 21篇 |
2005年 | 13篇 |
2004年 | 16篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 19篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 39篇 |
1997年 | 49篇 |
1996年 | 46篇 |
1995年 | 36篇 |
1994年 | 21篇 |
1993年 | 22篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 24篇 |
1988年 | 29篇 |
1987年 | 24篇 |
1986年 | 24篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 14篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 10篇 |
1976年 | 5篇 |
1975年 | 10篇 |
1974年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有849条查询结果,搜索用时 15 毫秒
121.
Mullerian duct cyst: diagnosis with MR imaging 总被引:1,自引:0,他引:1
122.
The effect of purified human fibroblast interferon on primary and secondary colony formation by blast progenitors from the peripheral blood of patients with acute myelogenous leukemia was examined. Interferon inhibited blast progenitors and normal granulocyte/macrophage progenitors (CFU-C) in a dose-dependent manner. The magnitude of this effect on blast progenitors and CFU was similar. Interferon also inhibited secondary plating of blast progenitors (self- renewal). This effect was in marked contrast to the effect of adriamycin, which reduced primary plating efficiency of blast progenitors but did not affect self-renewal. Inhibition of blast progenitor proliferation by interferon was markedly reduced when interferon was added after 24 hr of culture and was absent when added after 72 hr. Inhibition of self-renewal was observed even when interferon was added at 72 hr. We conclude that interferon inhibits both primary proliferation and self-renewal of blast progenitors and that this effect is not due to reduction in the number of primary colonies. These experiments provide an example of how cell culture techniques may be used to test antitumor agents for effects on important cellular events other than general cytotoxicity. 相似文献
123.
124.
Andreetti C Anile M Diso D Francioni F Venuta F De Giacomo T Di Stasio M Rendina EA Coloni GF 《Minerva chirurgica》2006,61(5):367-371
AIM: The esophageal perforations are associated with a high mortality and morbidity when they are not diagnosed and treated quickly. The aim of our study is to analyze the treatment and prognosis of the distal iatrogenic esophageal perforations on the basis of time of onset, concomitant disease and size of perforations. METHODS: The retrospective review was performed on 10 patients treated for distal iatrogenic esophageal perforations at our Institution from 1994 to 2003. The cause of perforations was: pneumatic dilation (7 patients) and esophageal endoprosthesis placing (3 patients). Seven patients presented within 24 h (Group A), and 3 patients presented after 24 h (Group B). In Group A, 4 patients underwent primary repair, 2 patients required esophagectomy and 1 patient was treated conservatively. In Group B, 2 patients were treated conservatively and 1 patient required an esophagectomy. RESULTS: Hospital morbidity was 20% and mortality was 30%. In Group A no patients died. In Group B hospital mortality was 100%. The most common cause of death was multiorgan failure resulting from sepsis. CONCLUSIONS: The prognosis for esophageal perforations is influenced by the time elapsed between diagnosis and treatment. Esophagectomy is indicated for patients with extensive perforation and necrosis of the esophagus when primary repair cannot be carried out. It is indicated also as treatment for the concomitant disease. 相似文献
125.
126.
MP Busch ; EA Operskalski ; JW Mosley ; CE Stevens ; ER Schiff ; SH Kleinman ; H Lee ; M Lee ; M Harris 《Transfusion》1994,34(10):858-864
BACKGROUND: The long-term course of human immunodeficiency virus type 1 (HIV-1)-related disease among seropositive blood donors has not been described. The enrollment and epidemiologic background of HIV-1- infected donors in the Transfusion Safety Study and their immunologic and clinical progression are described. STUDY DESIGN AND METHODS: Through the testing of approximately 200,000 sera from donations made in late 1984 and early 1985, 146 anti-HIV-1-positive donors and 151 uninfected matched donors were enrolled. These two cohorts were followed with 6-month interval histories and laboratory testing. RESULTS: Seropositive donors detected before the institution of routine anti-HIV-1 screening disproportionately were first-time donors and men with exclusively male sexual contacts. The actuarial probability of a person's developing AIDS within 7 years after donation was 40 percent; the probability of a person's dying of AIDS was 28 percent. AIDS developed more often when the donor was p24 antigen-positive at donation. Over a 3-year period, significant decreases occurred in CD4+, CD2+CD26+, CD4+CD29+, and CD20+CD21+ counts, but not in CD8+ subsets, CD20+, or CD14+. CONCLUSION: The high proportions of first-time donations and exclusively homosexual men among seropositive donors suggest that test-seeking may have contributed to the high HIV-1 prevalence in the repository. Implementation of alternative test sites when routine donor screening began in 1985 may have averted many high- risk donations. The disease course in HIV-1-infected donors had the same wide spectrum of immunologic and clinical manifestations as were reported for other cohorts. 相似文献
127.
C Oliveira RA Navarro-Xavier EA Anjos-Vallota JO Martins VLF Silveira LRC Gon?alves MS Araújo G Motta P Sannomiya MLV Oliva 《British journal of pharmacology》2010,161(4):899-910
BACKGROUND AND PURPOSE
The serine and cysteine peptidase inhibitor, BbCI, isolated from Bauhinia bauhinioides seeds, is similar to the classical plant Kunitz inhibitor, STI, but lacks disulphide bridges and methionine residues. BbCI blocks activity of the serine peptidases, elastase (Kiapp 5.3 nM) and cathepsin G (Kiapp 160.0 nM), and the cysteine peptidase cathepsin L (Kiapp 0.2 nM). These three peptidases play important roles in the inflammatory process.EXPERIMENTAL APPROACH
We measured the effects of BbCI on paw oedema and on leucocyte accumulation in pleurisy, both induced by carrageenan. Leucocyte–endothelial cell interactions in scrotal microvasculature in Wistar rats were investigated using intravital microscopy. Cytokine levels in pleural exudate and serum were measured by elisa.KEY RESULTS
Pretreatment of the animals with BbCI (2.5 mg·kg−1), 30 min before carrageenan-induced inflammation, effectively reduced paw oedema and bradykinin release, neutrophil migration into the pleural cavity. The number of rolling, adhered and migrated leucocytes at the spermatic fascia microcirculation following carrageenan injection into the scrotum were reduced by BbCI pretreatment. Furthermore, levels of the rat chemokine cytokine-induced neutrophil chemo-attractant-1 were significantly reduced in both pleural exudates and serum from animals pretreated with BbCI. Levels of interleukin-1β or tumour necrosis factor-α, however, did not change.CONCLUSIONS AND IMPLICATIONS
Taken together, our data suggest that the anti-inflammatory properties of BbCI may be useful in investigations of other pathological processes in which human neutrophil elastase, cathepsin G and cathepsin L play important roles. 相似文献128.
Background and purpose:
K+ channels play a role in the proliferation of cancer cells. We have investigated the effects of specific K+ channel inhibitors on basal and oestrogen-stimulated proliferation of breast cancer cells.Experimental approach:
Using the mammary adenocarcinoma cell line MCF-7 we assayed cell proliferation by radiolabelled thymidine incorporation in the absence or presence of various K+ channel inhibitors with or without 17β-oestradiol.Key results:
Inhibitors of Kv10.1 and KCa3.1 K+ channels suppressed basal proliferation of MCF-7 cells, but not oestrogen-stimulated proliferation. TRAM-34, a specific inhibitor of KCa3.1 channels increased or decreased cell proliferation depending on the concentration. At intermediate concentrations (3–10 µM) TRAM-34 increased cell proliferation, whereas at higher concentrations (20–100 µM) TRAM-34 decreased cell proliferation. The enhancement of cell proliferation caused by TRAM-34 was blocked by the oestrogen receptor antagonists ICI182,780 and tamoxifen. TRAM-34 also increased progesterone receptor mRNA expression, decreased oestrogen receptor-α mRNA expression and reduced the binding of radiolabelled oestrogen to MCF-7 oestrogen receptor, in each case mimicking the effects of 17β-oestradiol.Conclusions and implications:
Our results demonstrate that K+ channels Kv10.1 and KCa3.1 play a role in basal, but not oestrogen-stimulated MCF-7 cell proliferation. TRAM-34, as well as inhibiting KCa3.1, directly interacts with the oestrogen receptor and mimics the effects of 17β-oestradiol on MCF-7 cell proliferation and gene modulation. Our finding that TRAM-34 is able to activate the oestrogen receptor suggests a novel action of this supposedly specific K+ channel inhibitor and raises concerns of interpretation in its use. 相似文献129.
Rendina D Mossetti G De Filippo G Cioffi M Strazzullo P 《The Journal of clinical endocrinology and metabolism》2006,91(3):959-963
CONTEXT: Nephrolithiasis affects about 10% of the population in industrialized countries, with calcium salts composing more than 80% of renal stones. A significant percentage of patients with calcium nephrolithiasis and normal parathyroid function show hypophosphatemia and reduced renal phosphate reabsorption (i.e. a renal phosphate leak). OBJECTIVES: The objective of the study was to compare serum levels of fibroblast growth factor 23 (FGF23), a regulator of phosphate homeostasis, in 110 recurrent stone formers with or without renal phosphate leak, six patients affected by X-linked hypophosphatemic rickets, five patients affected by oncogenic osteomalacia, and 60 unrelated healthy controls. DESIGN: This was a prospective interventional study. METHODS: Renal phosphate leak was identified based on the occurrence of idiopathic hypophosphatemia [serum phosphate concentration < 2.50 mg/dl (<0.80 mmol/liter)] and reduced renal threshold phosphate concentration [<2.2 mg/liter (<0.70 mmol/liter)]. RESULTS: In 22 stone formers with renal phosphate leak, serum FGF23 concentration was significantly higher as compared with 88 stone formers without renal phosphate leak and with controls [83.3 (65.6-101.1) vs. 32.1 (26.8-37.4) and 24.5 (19.8-29.1) reference units (RU)/ml, respectively]. Stone formers with renal phosphate leak showed lower FGF23, compared with patients with oncogenic osteomalacia and X-linked hypophosphatemic rickets [572.3 (235.9-908.7) RU/ml]. Among stone formers and controls, serum FGF23 concentration displayed a strong inverse association with serum phosphate (r = -0.784, P = 0.009) and the rate of tubular phosphate reabsorption (r = -0.791, P = 0.008). CONCLUSIONS: In our study population, renal phosphate leak affected 20% of stone formers and was strongly associated with increased serum FGF23 concentration. 相似文献
130.