全文获取类型
收费全文 | 12693篇 |
免费 | 922篇 |
国内免费 | 68篇 |
专业分类
耳鼻咽喉 | 282篇 |
儿科学 | 247篇 |
妇产科学 | 212篇 |
基础医学 | 1919篇 |
口腔科学 | 292篇 |
临床医学 | 1212篇 |
内科学 | 2745篇 |
皮肤病学 | 310篇 |
神经病学 | 1214篇 |
特种医学 | 789篇 |
外国民族医学 | 3篇 |
外科学 | 1719篇 |
综合类 | 141篇 |
一般理论 | 4篇 |
预防医学 | 814篇 |
眼科学 | 95篇 |
药学 | 885篇 |
中国医学 | 11篇 |
肿瘤学 | 789篇 |
出版年
2023年 | 49篇 |
2022年 | 123篇 |
2021年 | 248篇 |
2020年 | 128篇 |
2019年 | 204篇 |
2018年 | 251篇 |
2017年 | 209篇 |
2016年 | 281篇 |
2015年 | 369篇 |
2014年 | 407篇 |
2013年 | 529篇 |
2012年 | 865篇 |
2011年 | 910篇 |
2010年 | 497篇 |
2009年 | 479篇 |
2008年 | 838篇 |
2007年 | 884篇 |
2006年 | 800篇 |
2005年 | 825篇 |
2004年 | 795篇 |
2003年 | 773篇 |
2002年 | 688篇 |
2001年 | 154篇 |
2000年 | 122篇 |
1999年 | 166篇 |
1998年 | 156篇 |
1997年 | 171篇 |
1996年 | 125篇 |
1995年 | 116篇 |
1994年 | 101篇 |
1993年 | 102篇 |
1992年 | 80篇 |
1991年 | 76篇 |
1990年 | 63篇 |
1989年 | 80篇 |
1988年 | 54篇 |
1987年 | 56篇 |
1986年 | 62篇 |
1985年 | 49篇 |
1984年 | 64篇 |
1983年 | 57篇 |
1982年 | 73篇 |
1981年 | 56篇 |
1980年 | 59篇 |
1979年 | 46篇 |
1978年 | 35篇 |
1977年 | 35篇 |
1975年 | 40篇 |
1974年 | 34篇 |
1972年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Bobby Tingstedt Elinor Bexe-Lindskog Mats Ekelund Roland Andersson 《Acta chirurgica》2002,168(11):579-582
OBJECTIVE: To evaluate the outcome of patients treated for appendiceal abscess, and managed either conservatively or surgically, and to describe the short and long-term outcome as well as incidence of interval appendicectomy in those treated conservatively. DESIGN: Retrospective study. SETTING: University hospital, Sweden. PATIENTS: Ninety-three patients with the diagnosis of appendiceal abscess, 50 treated conservatively and 43 who were operated on, with a mean age of 46 (14-93) years. Mean (range) follow-up for patients operated on was 65 (11-135) and for those treated conservatively 66 (6-136) months. MAIN OUTCOME MEASURES: Course of acute disease, recorded complications, recurrence of appendicitis and incidence of interval appendicectomy during follow-up. RESULTS: The duration of pain before admission was 4 (0.5-82) days for those operated on and 7 (2-60) days for those treated conservatively. A palpable mass was more common in the conservatively managed group. Complications were common among patients who were operated on. No interval appendicectomies were done during the second half of the study period. 4 of the patients treated conservatively (8%) had an underlying tumour diagnosed at follow-up. CONCLUSIONS: Operative management of patients with appendiceal masses seems to be associated with a high risk of postoperative complications and the risk of a more extensive surgical procedure. If possible, a conservative approach should be advocated. Because of inaccurate radiological imaging during the acute phase and the risk of an underlying malignancy, routine follow-up is necessary. Routine interval appendicectomy cannot be recommended. 相似文献
42.
43.
Roland J. Lamarine H.S.D. 《Journal of community health》1988,13(3):143-155
Native Americans have experienced substantial problems with alcohol since its introduction to their culture by early European settlers. Epidemiological data indicate that elevated morbidity and mortality attributable to alcohol abuse among this population remain at epidemic levels. Adolescent drinking patterns and family and peer influences on alcohol use are examined. A multifactorial etiology is indicated in the origin of Native American alcohol abuse. Some scholars have ascribed this problem to historical factors such as the introduction of alcohol to Native Americans by aberrant role models, while other researchers subscribe to various physiological theories which support the firewater myth suggesting that Native Americans may be genetically predisposed to crave ever increasing doses of alcohol during a rapid loss of control of their senses. The physiological theories generally suggest significant differences in alcohol absorption and metabolism rates between Native Americans and caucasians. A wide variety of social factors appear to be implicated in Native American drinking problems. Cultural and social orientations, socioeconomic conditions, stake theory, failure to develop social sanctions regulating drunken deportment, passive-aggressive syndromes, and emotional repression contribute to Native American alcohol abuse. Treatment regimes for Native American alcoholics are examined briefly. Nativistic movements, conversion to evangelistic religions, therapies grounded in the medical model, and Native American group-oriented efforts have demonstrated varying degrees of success. Clearly, prevention would be preferable to the frustration of attempting to change the highly addictive behavior patterns characteristic of alcoholism. Suggestions for health education interventions are presented including an example of one effort currently being implemented.Roland J. Lamarine, H.S.D. is Assistant Professor Department of Health and Community Services, California State University, Chico, Chico, California 95929-0505 相似文献
44.
A comparative isokinetic evaluation of a functional ankle orthosis on talocalcaneal function 总被引:1,自引:0,他引:1
The purpose of this study was to determine the effectiveness of a semirigid orthosis in restricting ankle inversion-eversion range of motion (ROM), and evaluate its effect on subjects' ability to produce muscular torque, during pre- and post-exercise test conditions. Thirty healthy subjects, 15 males and 15 females, with no history of right ankle injury were evaluated. Active ankle inversion-eversion torque and angular displacement were measured on a LIDO(R) isokinetic system, with the subjects' right ankle positioned in 0 degrees of plantarflexion. T-tests for paired samples at the 0.001 confidence level revealed that the orthosis demonstrated significant inversion-eversion range restrictive capabilities; did not interfere with maximum inversion-eversion torque production; and retained its support effectiveness following 20 minutes of dynamic exercise. The results suggest that the tested orthosis may be an effective prophylactic in preventing ankle sprains and beneficial to individuals with chronic ligamentous instability. J Orthop Sports Phys Ther 1989;11(6):245-252. 相似文献
45.
Michael Schirner Frank Herzberg Roland Schmidt Michael Streit Michael Schoning Michael Hummel Christine Kaufmann Eckhard Thiel Ernst-Dieter Kreuser 《Clinical & experimental metastasis》1997,16(5):427-435
The integrin 51 seems to be the most relevant receptor of tumor cells for binding to fibronectin. Although numerous studies suggest a role of tumor cell fibronectin interaction in tumor metastasis, differential integrin expression on tumor cells has, however, not been correlated with metastatic capabilities. We addressed this question by transfection of the integrin 51 cDNA into HT-29 human colon carcinoma cells which led to de novo expression of functional integrin 51. Similar to other reports, expression of the integrin 51 in HT-29 tumor cells exerted an inhibitory action on cell proliferation as indicated in our study by formation of fewer colonies in soft agar. The tumor growth inhibitory property of the integrin 51 was also shown by reduction of subcutaneous xenograft growth in nude mice to approximately 50% of that of control transfectants. For the first time, we found that several clones of integrin 5 subunit transfectants displayed dramatically reduced formation of lung colonies and cutaneous metastasis after intravenous injec-tion into nude mice. While most animals inoculated with control transfectant cells formed macroscopically visible lung colonies ranging from 12.6 ± 2.6 to 22.0 ± 6.6 (mean colony number ± SEM), mice inoculated with HT-29 cell clones expressing the integrin a5b1 were almost completely free of lung colonies (ranging from 0.0 ± 0 to 0.2 ± 0.1). Our results imply that integrin 51 expression inhibits circulating tumor cells in pursuing late steps of the metastatic process as represented by the artificial metastasis (lung colonisation) model. © Rapid Science Ltd. 相似文献
46.
Inhibition of HIV-1 by modification of a host membrane protease 总被引:3,自引:0,他引:3
Bristow Cindy L.; Fiscus Susan A.; Flood Patrick M.; Arnold Roland R. 《International immunology》1995,7(2):239-249
While it is clear that CD4 Is the receptor for the gp120 envelopeprotein of HIV-1, substantial evidence suggests that other hostcell proteins are required for successful membrane fusion. Studieswere initiated to examine the potential for a protein receptorwhich has an elastase-like character to participate in fusionof HIV-1 with permissive host cells. A synthetic elastase inhibitorwas shown to significantly reduce HIV-1 infectivity when presentduring, but not after, the initial contact between virus andcells. A human T cell elastase-like membrane component was purifiedand shown to be lipid-associated. By competitive Inhibition,the purified protein was shown to bind gp160 within the HIV-1fusion domain. The binding parameters of whole T cell membraneextract, with a hydrophobic pentapeptide representative of thefusion domain, suggested an elastase-like protein is the single,secondary T cell receptor for HIV-1 (K = 1x103 M–1). Thepentapeptide interacted with porcine and human (epithelial andpolymorphonuclear leukocyte), but not murine, elastase isoforms,suggesting its participation In the permissiveness of host cellsto infection. 相似文献
47.
Cytogenetic and comparative genomic hybridization findings in four cases of breast cancer after neoadjuvant chemotherapy 总被引:1,自引:0,他引:1
Fazeny-Dörner B Piribauer M Wenzel C Fakhrai N Pirker C Berger W Sedivy R Rudas M Filipits M Okamoto I Marosi C 《Cancer Genetics and Cytogenetics》2003,146(2):161-166
To assess a potential common pattern of genetic alterations in chemotherapy-resistant tumors we analyzed four tumors from breast cancer patients (patients 1-4) after neoadjuvant chemotherapy, by comparative genome hybridization (CGH) and conventional chromosome banding analysis. All patients showed structural aberrations involving chromosomes 1, 5, 11, 16, and 17. In CGH analysis, the patients showed typical imbalances for ductal breast cancer: gains of 1q (3 patients), 5q (2 patients), 8q (3 patients), and X (4 patients) and losses of 1p33 approximately p36 (3 patients), 16q (3 patients), 17p (3 patients), 19 (4 patients), and 22q (4 patients). Other recurrent imbalances of atypical pattern for ductal breast cancer were gain of 4q21 approximately q32 (2 patients), 20q21 approximately q22 (2 patients), and 21 (2 patients) and loss of 20p (3 patients). Three patients showed involvement of several regions bearing genes of drug resistance (MDR1 [HUGO symbol: ABCB1], BCRP [HUGO symbol: ABCG2], MRP1 [HUGO symbol: ABCC1], RFC1); the fourth patient displayed an amplification in the region of MYC (alias c-myc), thus providing--at the level of the light microscope--an explanatory background for the ability of their tumors to survive anthracycline-, taxane- and cyclophosphamide-based chemotherapy. Conventional cytogenetic analysis and CGH displayed highly coincidental findings in the tumors of four patients after neoadjuvant chemotherapy for breast cancer. 相似文献
48.
49.
Reich SM Wichmann M Frankenberger R Zajc D 《Journal of biomedical materials research. Part B, Applied biomaterials》2005,74(2):740-746
The aim of this study was to evaluate the shear bond strength of three resin cements to Vita Mark II ceramics under different pretreatments of the ceramic surface and to examine whether simplified pretreatment procedures would result in satisfying results compared to the state of the art. RelyX Unicem (RXU), Calibra (CAL), and Variolink II (VAR) were used as resin cements and bonded to machine milled feldspatic disks, pretreated in five different ways. (1) no pretreatment of the ceramic surface; (2) surface etched with hydrofluoric acid (HF); (3) ceramic surface silanized; (4) ceramic surface etched (HF) and silanized, (5) ceramic surface etched (HF), silanized, and covered with Heliobond. The shear bond strengths were measured initially, after 5000 and 10,000 thermocycles (TC). After 10,000 TC for CAL only procedure 5 resulted in a reliable adhesion median value of 10.7 MPa. VAR showed median values of 24.6, 17.2, and 18.1 MPa for pretreatments 5, 3, and 4, respectively. RXU performed 25.9, 22.0, and 11.0 MPa for procedures 5, 4, and 3, respectively. For procedure 2, RXU revealed the significantly highest value with 15.4 MPa (U-test, p = 0.05). Only RXU-luted specimens of procedure 1 survived the 10,000 thermocycles. The results revealed that a simplification of the ceramic pretreatment for VAR and RXU might be possible. 相似文献
50.
Steffen Dietzel Anna Jauch Dirk Kienle Guoquiong Qu Heidi Holtgreve-Grez Roland Eils Christian Munkel Michael Bittner Paul S. Meltzer Jeffrey M. Trent Thomas Cremer 《Chromosome research》1998,6(1):25-33
Fluorescence in situ hybridization (FISH) with microdissection probes from human chromosomes 3 and 6 was applied to visualize arm and subregional band domains in human amniotic fluid cell nuclei. Confocal laser scanning microscopy and quantitative three-dimensional image analysis showed a pronounced variability of p- and q-arm domain arrangements and shapes. Apparent intermingling of neighbouring arm domains was limited to the domain surface. Three-dimensional distance measurements with pter and qter probes supported a high variability of chromosome territory folding. 相似文献