全文获取类型
收费全文 | 6804篇 |
免费 | 479篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 103篇 |
儿科学 | 166篇 |
妇产科学 | 97篇 |
基础医学 | 796篇 |
口腔科学 | 332篇 |
临床医学 | 523篇 |
内科学 | 1693篇 |
皮肤病学 | 144篇 |
神经病学 | 648篇 |
特种医学 | 245篇 |
外科学 | 973篇 |
综合类 | 17篇 |
预防医学 | 284篇 |
眼科学 | 116篇 |
药学 | 553篇 |
中国医学 | 14篇 |
肿瘤学 | 630篇 |
出版年
2024年 | 9篇 |
2023年 | 67篇 |
2022年 | 178篇 |
2021年 | 320篇 |
2020年 | 174篇 |
2019年 | 245篇 |
2018年 | 276篇 |
2017年 | 198篇 |
2016年 | 263篇 |
2015年 | 294篇 |
2014年 | 334篇 |
2013年 | 424篇 |
2012年 | 570篇 |
2011年 | 562篇 |
2010年 | 305篇 |
2009年 | 262篇 |
2008年 | 435篇 |
2007年 | 411篇 |
2006年 | 411篇 |
2005年 | 363篇 |
2004年 | 330篇 |
2003年 | 225篇 |
2002年 | 214篇 |
2001年 | 33篇 |
2000年 | 24篇 |
1999年 | 36篇 |
1998年 | 35篇 |
1997年 | 27篇 |
1996年 | 18篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 16篇 |
1992年 | 25篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 14篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 7篇 |
1965年 | 3篇 |
排序方式: 共有7334条查询结果,搜索用时 15 毫秒
11.
Association of a common polymorphism in the cyclooxygenase 2 gene with risk of non-small cell lung cancer 总被引:2,自引:2,他引:0
Campa Daniele; Zienolddiny Shanbeh; Maggini Valentina; Skaug Vidar; Haugen Aage; Canzian Federico 《Carcinogenesis》2005,26(6):1157
Carcinogenesis, 25, 229235, 2004 We reported the association of 相似文献
12.
Immunological and echocardiographic evaluation of decellularized versus cryopreserved allografts during the Ross operation. 总被引:3,自引:0,他引:3
Francisco Diniz Affonso da Costa Pascal Maria Dohmen Daniele Duarte Cristina von Glenn Sérgio Veiga Lopes Hermínio Haggi Filho Marise Brenner Affonso da Costa Wolfgang Konertz 《European journal of cardio-thoracic surgery》2005,27(4):572-578
OBJECTIVE: Compare the immunological and echocardiographic data of decellularized versus cryopreserved allografts used for RVOT reconstruction during Ross operation. METHODS: From 16/01/03 thru 07/10/03, 20 Ross operations were performed using decellularized (n=11) or cryopreserved (n=9) allografts. Echocardiography was done at discharge, 1, 3, 6 and 12 months and annually thereafter. Samples for determination of antibodies against HLA class I and II were obtained preoperatively and at days 5, 10, 30, 90 and 180 postoperatively. These samples were tested by the ELISA method in LAT-M dishes (unspecific) for identification of circulating antibodies and the results expressed as mean sample values (Is=DO/cutoff). If positive, LAT-E (specific) was performed and PRA levels determined. RESULTS: There was no mortality. Cryopreserved allografts showed marked Is values elevations for class I and II antibodies which started at the first month and remained elevated up to 6 months. In contrast, of the patients receiving decellularized allografts, seven remained negative, two patients had only marginal elevation of class I antibodies and two patients showed abnormal elevations of PRA levels. This response happened earlier than in the cryopreserved group, starting on the 5th postoperative day and has returned to baseline levels in one case. Echocardiography showed mild, but significant, elevation of gradients in cryopreserved valves but none in the decellularized. CONCLUSIONS: Decellularized allografts had normal function up to 18 months and showed important reduction of the immunogenic response when compared to cryopreserved valves. 相似文献
13.
Nir Peled David Shitrit Daniele Bendayan Mordechai R Kramer 《European journal of cardio-thoracic surgery》2006,30(4):680-1; discussion 682
Stent insertion for bronchial stenosis has become common practice in lung transplantation and advanced lung malignancy, and for external compression of the airways for other reasons. Right main bronchus stenting may require blocking the right upper lobe by the stent, placing the patient at risk of recurrent pneumonia and atelectasis. In this study, three patients after insertion of a metal stent to the right main bronchus are described. In all cases, the right upper lobe was covered by the stent, and a laser (Nd:YAG) procedure was used to open a 'window' in the stent toward the right upper lobe with a follow-up of 1 year. We conclude that stent insertion to the right main bronchus may be followed by a laser therapy to open a 'window' toward the right upper lobe. 相似文献
14.
Eugenia Daniele Giulio Villani Marcello D. Lograno 《European journal of pharmacology》1997,330(2-3):247-256
The aim of the research was to characterize muscarinic receptors of bovine ciliary muscle and to investigate the desensitization process. The role of protein kinase C was analyzed. The results show that muscarinic receptors of bovine ciliary muscle have the pharmacological characteristics of the M3 subtype. Acute exposure to phorbol esters (1 μM phorbol 12,13-dibutyrate, PDB, or 0.1 μM phorbol 12-myristate 13-acetate, PMA, for 15 and 5 min, respectively) resulted in antagonism of muscarinic receptor-mediated contraction. Long-term pretreatment (18 h) with PMA to down-regulate protein kinase C resulted in potentiation of carbachol-induced contraction, reduction of agonist-induced desensitization and loss of phorbol ester-induced desensitization. Staurosporine (3 μM) and H7 [1-(5-isoquinolinesulfonyl)-2-methyl-piperazine] (1 μM), protein kinase C inhibitors, produced a significant potentiation of the contractile effect of carbachol, reduced the desensitization produced by repeated addition of carbachol and suppressed that induced by phorbol esters. In vitro incubation with carbachol, PDB or PMA did not cause any modification of the binding of labeled [3H]quinuclidinyl benzilate. In vitro incubation with PDB and PMA produced, as expected, a significant translocation of protein kinase C from the cytosol to the membrane. The incubation of the ciliary muscle with carbachol, using the protocol of exposure that induced maximal desensitization of contractile responses, produced a significant redistribution of the enzyme from the cytosol to the membrane. These findings suggest that agonist-induced modulation of functional cholinergic sensitivity in ciliary muscle is correlated, at least partially, to the translocation of protein kinase C from the cytosol to the membrane. The desensitization by phorbol esters is completely due to protein kinase C activation; during the desensitization process, direct modification of the density and affinity of muscarinic receptors is not involved. 相似文献
15.
Steven S Clark Li Zhong Daniele Filiault Sarah Perman Zhibin Ren Michael Gould Xinhai Yang 《Clinical cancer research》2003,9(12):4494-4504
PURPOSE: Perillyl alcohol (POH) displays preventive and therapeutic activity against a wide variety of tumor models, and it has been suggested that this might be associated with the ability of POH to interfere with Ras prenylation. POH also selectively induces G(1) arrest and apoptosis in Bcr/Abl-transformed hematopoietic cells. Because signaling through Ras is necessary for Bcr/Abl transformation, we examined whether POH induces its anti-leukemia effect by inhibiting Ras signaling. EXPERIMENTAL DESIGN: The ability of POH to inhibit posttranslational farnesylation and signaling from Ras as well as signaling through the Raf-Mek-Erk cascade was examined in Bcr/Abl-transformed and mock-transformed cells and related to the anti-leukemia effect of POH. RESULTS: POH does not affect Ras prenylation or Ras activity, but it blocks signaling downstream of Ras by reversing the state of activation of the Erk kinase, Mek. POH affects Mek activity only when it is added to intact cells. Treatment of either cell lysates or of purified Mek with POH has no effect on Mek activity. Inhibition of the Mek-Erk pathway seems to be related to the POH anti-leukemia effect for the following reasons: (a) the concentration of POH needed to block the Erk pathway, as well the kinetics with which POH inhibits this signaling cascade, both correlate with the anti-leukemia effect of POH; (b) both U0126 (a specific Mek inhibitor) and POH induce similar anti-leukemia effects; and (c) mock-transformed hematopoietic cells are simultaneously resistant to POH anti-leukemia effects and inhibition of the Mek-Erk pathway. CONCLUSION: Blocking Mek is sufficient to induce growth arrest and apoptosis in Bcr/Abl-transformed cells; therefore, POH represents a novel small molecule inhibitor of Mek that might be effective for treating Bcr/Abl leukemias. 相似文献
16.
Livio Presutti Matteo Alicandri Ciufelli Daniele Marchioni Domenico Villari Alessio Marchetti Francesco Mattioli 《Otolaryngology--head and neck surgery》2007,136(3):369-372
OBJECTIVE: The aim of this paper was to describe our surgical technique for the treatment of nasal septal perforations. STUDY AND DESIGN: We studied 31 patients with nasal septal perforation treated with an endoscope-assisted technique, based on a bilateral dissection of monopedicled mucosal flaps from the nasal fossa floor, sutured at the edge of the perforation previously unstuck, without any graft interposed between the two mucosal layers. RESULTS: In our experience with 31 patients, the use of this technique led to the persistent closing (with follow-up for at least one year) of 96.3% of the perforations smaller than 3 cm. CONCLUSIONS: Our technique has the advantage of an endonasal approach, without any external incision, and the use of monopedicled flaps from the nasal fossa floor without any graft interposition, avoiding any other surgical procedure and morbidity in the donor site of the graft. The use of nasal endoscopy permits superior precision in all surgical steps. SIGNIFICANCE: The high success rate in perforations smaller than 3 cm seems to confirm the effectiveness of this technique. 相似文献
17.
Stefano Miceli Sopo Daniele Radzik Mauro Calvani 《Pediatric allergy and immunology》2007,18(7):575-582
Investigators have tried to identify a level of seric specific immunoglobulin E (IgE) that had a sufficient predictive value to diagnose a food allergy without having will resort to the food challenge. To search in literature, all the studies that have estimated the possibility to identify a level of seric specific cow milk IgE with a positive predictive value (PPV) of 95% for the first diagnosis of cow's milk allergy (CMA) in pediatric age. We have identified six studies, nearly all studies suffer from relevant methodological bias. Proposed cut-off are all different. The studied pediatric populations were highly selected. Also neglecting the methodological bias of the studies and the great difference of value between the proposed cut-off, it always remains to consider that the pre-test probability of having a CMA between the children enrolled in the six studies included in this review is particularly high. The likelihood ratio helps to transfer the results of a study on a diagnostic test just to our population, and it is more realistic rather than to entrust itself to the PPV or the negative predictive value, that are much influenced from the prevalence of the disease in the studied population. 相似文献
18.
Bruno Zappacosta Silvia Persichilli Donata Scribano Angelo Minucci Daniele Lazzaro Pasquale De Sole Bruno Giardina 《Clinical chemistry and laboratory medicine》2002,40(11):1139-1142
Slightly elevated values of homocysteine are commonly associated with thromboembolic diseases, while high values can be found in patients with congenital metabolic defects or nutritional problems. The clinical use of homocysteine as an independent marker of cardiovascular disease was limited in the past by technical problems with its measurement, the instrumentation (HPLC, radioenzymatic assays, gas chromatography-mass spectrometry, etc.) and the necessary skills required. Commercially available immunoassays now permit a simpler and more rapid measurement of homocysteine, that is more suitable for routine clinical laboratories; in this paper we analyze the results obtained by using three fully automated methods for homocysteine determination (Abbott IMx immunoassay, Abbott AxSYM immunoassay and Immulite 2000 homocysteine immunoassay) and their correlation with the widely used HPLC method. The results clearly indicate that all three automated immunochemical methods correlate well with the HPLC method (slope 0.97-1.03; intercept 0.95-1.91 with a recovery above 95% for all three methods). 相似文献
19.
F. M. Ulivieri L. P. Piodi G. Marotta D. Marchelli C. Commadini L. Parravicini C. Verdoia P. Gerundini 《Journal of orthopaedics and traumatology》2006,7(4):192-194
Osteoprotegerin (OPG) is a protein that inhibits of osteoclastogenesis. The aim this study was to evaluate the response of
serum OPG levels to neridronate treatment in patients with Paget's disease of bone resistant to previous therapy. Nine patients
(4 men) affected by active Paget’s disease of bone (6 polyostotic, 3 monostotic) not responsive to clodronate were studied.
Serum OPG, osteocalcin, total and bone isoenzyme of alkaline phosphatase (AP and BAP, respectively), and urinary deoxypyridinoline
(DPD) were measured before and 5 months after neridronate treatment (100 mg/day, i.v. for two days). A scintigraphic activity
index (SAI) was also calculated before treatment. Mean baseline OPG levels were within normal values and were not significantly
different 5 months after neridronate treatment. In contrast, there were significant reductions in AP (41.9%, p<0.02) and BAP (38.8%, p<0.04). Serum OPG levels correlated with DPD (r=0.925) and SAI (r=0.689). Although OPG is an important regulator of bone metabolism,
in our series of already treated patients it was not a sensitive marker for diagnosing Paget's disease and for monitoring
the response to pharmacological treatment, whereas AP and BAP confirmed their clinical usefulness. This preliminary study
requires confirmation by a study with a larger population. 相似文献
20.
Sinotubular junction reconstruction in reimplantation type of valve-sparing aortic procedure can present some problem when a Valsalva graft is used. Since in the Valsalva graft the sinotubular junction height is predetermined, correct matching with native commissures height can be difficult. We propose a method by which it is possible to create a new sinotubular junction in Valsalva graft without altering its original configuration. 相似文献