全文获取类型
收费全文 | 15069篇 |
免费 | 1102篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 204篇 |
儿科学 | 249篇 |
妇产科学 | 201篇 |
基础医学 | 2257篇 |
口腔科学 | 158篇 |
临床医学 | 1539篇 |
内科学 | 3619篇 |
皮肤病学 | 388篇 |
神经病学 | 1630篇 |
特种医学 | 645篇 |
外国民族医学 | 10篇 |
外科学 | 2316篇 |
综合类 | 44篇 |
一般理论 | 5篇 |
预防医学 | 682篇 |
眼科学 | 201篇 |
药学 | 949篇 |
中国医学 | 14篇 |
肿瘤学 | 1126篇 |
出版年
2024年 | 18篇 |
2023年 | 163篇 |
2022年 | 279篇 |
2021年 | 646篇 |
2020年 | 350篇 |
2019年 | 542篇 |
2018年 | 650篇 |
2017年 | 423篇 |
2016年 | 474篇 |
2015年 | 547篇 |
2014年 | 730篇 |
2013年 | 873篇 |
2012年 | 1327篇 |
2011年 | 1302篇 |
2010年 | 702篇 |
2009年 | 645篇 |
2008年 | 983篇 |
2007年 | 956篇 |
2006年 | 824篇 |
2005年 | 765篇 |
2004年 | 649篇 |
2003年 | 553篇 |
2002年 | 496篇 |
2001年 | 118篇 |
2000年 | 115篇 |
1999年 | 96篇 |
1998年 | 88篇 |
1997年 | 59篇 |
1996年 | 60篇 |
1995年 | 59篇 |
1994年 | 47篇 |
1993年 | 42篇 |
1992年 | 65篇 |
1991年 | 75篇 |
1990年 | 59篇 |
1989年 | 49篇 |
1988年 | 35篇 |
1987年 | 36篇 |
1986年 | 34篇 |
1985年 | 21篇 |
1984年 | 27篇 |
1983年 | 31篇 |
1982年 | 34篇 |
1981年 | 14篇 |
1980年 | 15篇 |
1979年 | 18篇 |
1978年 | 16篇 |
1977年 | 13篇 |
1974年 | 14篇 |
1972年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Weber S Doi K Massiello AL Byerman BP Takagaki M Fukamachi K Donahue A Chapman P Hirschman G Vitale N Smith WA 《ASAIO journal (American Society for Artificial Internal Organs : 1992)》2002,48(6):606-611
The purpose of this study was to evaluate the in vitro responses to preload and afterload of our total artificial heart (TAH), the MagScrew TAH. The TAH consists of two blood pumps and a control logic, developed at the Cleveland Clinic, OH, and the MagScrew actuator and its electronic control system, developed by Foster-Miller Technologies, Inc., Albany, NY. Tests were performed on a mock circulatory loop, using water as a test fluid. Preload sensitivity of the Mag-Screw TAH demonstrated a Frank-Starling response to preload in automatic mode. A peak flow of 10 L/min was obtained, with a left atrial pressure of 13 mm Hg. The relationship between right atrial pressure and left atrial pressure was well balanced when tested with a left bronchial shunt flow of 5% and a range of pulmonary artery and aortic pressures. With respect to afterload response, the left pump showed a relatively low sensitivity, which allowed the pump to maintain perfusion over a wide range of aortic pressures. The right pump, on the other hand, was much more sensitive to pulmonary artery pressure, which provided a measure of protection against pulmonary congestion. The very effective physiologic response of the MagScrew TAH is believed to result from employment of a left master, alternating ejection control logic, high inherent sensitivity of the blood pumps to atrial pressure, a lower effective stroke volume for the right pump, and a scaling of right side motor ejection voltage to 80% of that used for the left side ejection. 相似文献
102.
Nicolas L Monneret G Debard AL Blesius A Gutowski MC Salles G Bienvenu J 《Clinical immunology (Orlando, Fla.)》2001,98(3):358-363
The aim of our study was to compare CD3 expression on gammadelta T cells and alphabeta T cells in human patients. The antigen density of TCR and CD3 on both subsets was assessed by a quantitative method in eight patients. In parallel, we developed and validated a reliable direct tricolor staining protocol that we tested on samples from hospitalized and healthy individuals (n = 60). Our results demonstrate that human gammadelta T cells constitutively express approximately twofold more of the TCR/CD3 complex than alphabeta T cells. We suggest that this enhanced expression of the TCR/CD3 complex could contribute to the higher reactivity of gammadelta T cells compared to alphabeta T cells. These clinical laboratory results confirm the fundamental data described elsewhere. gammadelta T cells deserve further clinical investigations to understand their precise role in human immunity. 相似文献
103.
P. Legrand G. Fournier A. Buré V. Jarlier M. H. Nicolas D. Decré J. Duval A. Philippon 《European journal of clinical microbiology & infectious diseases》1989,8(6):527-529
In 210 strains ofEnterobacteriaceae which were isolated in four hospitals and which showed reduced susceptibility to cefotaxime, high synergy was demonstrated between amoxicillin (20µg) + clavulanate (10µg) and cefotaxime (30µg) using a simple double-disk test. Isoelectric focusing on gel and specific iodometric detection using ceftriaxone identified four extended broad-spectrum-lactamases (isoelectric points 7.6, 6.3, 7.0 and 5.9) produced by the strains. 相似文献
104.
Role of double-stranded RNA and Npro of classical swine fever virus in the activation of monocyte-derived dendritic cells 总被引:2,自引:0,他引:2
Classical swine fever virus (CSFV) is a noncytopathogenic (ncp) positive-sense RNA virus that replicates in myeloid cells including macrophages and dendritic cells (DC). The virus does not induce type I interferon (IFN-alpha/beta), which in macrophages has been related to the presence of the viral Npro gene. In the present work, the role of viral double-stranded (ds)RNA and Npro in the virus-host cell interaction has been analyzed. Higher levels of detectable dsRNA were produced by a genetically engineered cytopathogenic (cp) CSFV compared with ncp CSFV, and cp CSFV induced IFN-alpha/beta in PK-15 cells. With DC, there was only a small difference in the levels of dsRNA between the cp and ncp viruses, and no IFN-alpha/beta was produced. However, the cp virus induced a higher degree of DC maturation, in terms of CD80/86 and MHC II expression. Npro deletion mutants induced an increase in DC maturation and IFN-alpha/beta production-for both ncp and cp viruses-despite reduced replication efficiency in the DC. Deletion of Npro did not influence dsRNA levels, indicating that the interference was downstream of dsRNA turnover regulation. In conclusion, the capacity of CSFV to replicate in myeloid DC, and prevent IFN-alpha/beta induction and DC maturation, requires both regulated dsRNA levels and the presence of viral Npro. 相似文献
105.
Blümel JE Castelo-Branco C Kerrigan N Cancelo MJ Blümel B Haya J Flores M Carvajal MC Sarrá S 《Menopause (New York, N.Y.)》2003,10(3):235-240
OBJECTIVE: To assess the beliefs of climacteric women regarding their health, menopause, and hormone replacement therapy (HRT). DESIGN: Medical students asked to interview 526 healthy women, ranging from 40 to 64 years of age, between January and February of 2002. Of that number, 26 (4.9%) declined to participate in the interview. Thus, 500 women were interviewed about their beliefs and perceptions regarding their quality of life and health risks, as well as their opinions on menopause and HRT. RESULTS: The mean age of the sample was 53.3 +/- 6.2 years; 83.4% were postmenopausal, and 18.8% were HRT users. Of the women interviewed, 38.6% believed that their health was good. Although 78.8% thought that cancer is the main cause of death, 64% of them considered themselves to be at high risk for cardiovascular disease and osteoporosis. Most (64%) believed that menopause deteriorates the quality of life and that it increases cardiovascular risk (52.4%) and osteoporosis (72.0%). The HRT users perceived that they had better health status (48.9% v 36.2%, P < 0.02) and smaller cardiovascular risk (54.3% v 66.3%, P < 0.04) than did the nonusers; however, they ignored the preventive effect of estrogens in osteoporosis. CONCLUSIONS: Women believe that menopause deteriorates their health. The HRT users perceived themselves to be healthier and to have a smaller risk for cardiovascular disease. 相似文献
106.
107.
Vasopressin-induced taurine efflux from rat pituicytes: a potential negative feedback for hormone secretion 总被引:1,自引:0,他引:1
Lia Rosso Brigitta Peteri-Brunbäck Philippe Poujeol Nicolas Hussy Jean-Marc Mienville 《The Journal of physiology》2004,554(3):731-742
Previous work on the whole neurohypophysis has shown that hypotonic conditions increase release of taurine from neurohypophysial astrocytes (pituicytes). The present work confirms that taurine is present in cultured pituicytes, and that its specific release increases in response to a hypotonic shock. We next show that vasopressin (VP) and oxytocin (OT) also specifically release taurine from pituicytes. With an EC50 of ∼2 n m , VP is much more potent than OT, and the effects of both hormones are blocked by SR 49059, a V1a receptor antagonist. This pharmacological profile matches the one for VP- and OT-evoked calcium signals in pituicytes, consistent with the fact that VP-induced taurine efflux is blocked by BAPTA-AM. However, BAPTA-AM also blocks the taurine efflux induced by a 270 mosmol l−1 challenge, which per se does not evoke any calcium signal, suggesting a permissive role for calcium in this case. Nevertheless, the fact that structurally unrelated calcium-mobilizing agents and ionomycin are able to induce taurine efflux suggests that calcium may also play a signalling role in this event. It is widely accepted that in hypotonic conditions taurine exits cells through anionic channels. Antagonism by the chloride channel inhibitors 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) suggests the same pathway for VP-induced taurine efflux, which is also blocked in hypertonic conditions (330 mosmol l−1 ). Moreover, it is likely that the osmosensitivity of the taurine channel is up-regulated by calcium. These results, together with our in situ experiments showing stimulation of taurine release by endogenous VP, strengthen the concept of a glial control of neurohormone output. 相似文献
108.
A comparison of murine and human immunoproteomes of Helicobacter pylori validates the preclinical murine infection model for antigen screening
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bumann D Holland P Siejak F Koesling J Sabarth N Lamer S Zimny-Arndt U Jungblut PR Meyer TF 《Infection and immunity》2002,70(11):6494-6498
Preclinical mouse infection models are widely used for Helicobacter vaccine development, but how well such models mimic important aspects of human infections is unknown. A comparison of Helicobacter pylori immunoproteomes of infected mice with previously reported patient data reveals a high agreement in the antigens recognized, suggesting that H. pylori in vivo protein composition and recognition by the host immune system are comparable in mice and humans. Murine Helicobacter models may thus be valid to screen antigens for human vaccination. 相似文献
109.
Presence of autoantibodies to apolipoprotein A-1 in patients with acute coronary syndrome further links autoimmunity to cardiovascular disease 总被引:2,自引:0,他引:2
Vuilleumier N Reber G James R Burger D de Moerloose P Dayer JM Roux-Lombard P 《Journal of autoimmunity》2004,23(4):227-360
Anti-apolipoprotein A-1 (Apo A-1) autoantibodies were described in autoimmune disorders such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) and might be involved in the genesis of arterial and venous thrombotic events. To investigate the presence of these autoantibodies in patients with acute coronary syndrome (ACS) without other features of autoimmunity, we set up an enzyme-linked immunosorbent assay (ELISA) for anti-Apo A-1 antibodies. We used it to investigate their prevalence in ACS as compared to SLE and APS and correlated them to plasma Apo A-1 and serum amyloid A protein (SAA) concentrations. The prevalence of anti-Apo A-1 autoantibodies in the healthy control group was 1% (1/92), but was significantly higher in other groups: 21% (11/53) in ACS group (P=0.001), 13% (12/92) in SLE and/or APS group (P=0.005). Multiple linear regression revealed a significant correlation between plasma Apo A-1 (r=-0.72, P=0.013), plasma SAA concentration (r=0.76, P=0.0066) and anti-Apo A-1 IgG titre in ACS patients. The presence of anti-Apo A-1 autoantibodies in patients with ACS highlights an additional link between autoimmunity, inflammation and atherosclerosis. 相似文献
110.
Nguyen K Bassez G Bernard R Krahn M Labelle V Figarella-Branger D Pouget J Hammouda el H Béroud C Urtizberea A Eymard B Leturcq F Lévy N 《Human mutation》2005,26(2):165
DYSF encoding dysferlin is mutated in Miyoshi myopathy and Limb-Girdle Muscular Dystrophy type 2B, the two main phenotypes recognized in dysferlinopathies. Dysferlin deficiency in muscle is the most relevant feature for the diagnosis of dysferlinopathy and prompts the search for mutations in DYSF. DYSF, located on chromosome 2p13, contains 55 coding exons and spans 150 kb of genomic DNA. We performed a genomic analysis of the DYSF coding sequence in 34 unrelated patients from various ethnic origins. All patients showed an absence or drastic decrease of dysferlin expression in muscle. A primary screening of DYSF using SSCP or dHPLC of PCR products of each of 55 exons of the gene was followed by sequencing whenever a sequence variation was detected. All together, 54 sequence variations were identified in DYSF, 50 of which predicting either a truncated protein or one amino-acid substitution and most of them (34 out of 54) being novel. In 23 patients, we identified two pathogenic mutations, while only one was identified in 11 patients. These mutations were widely spread in the coding sequence of the gene without any mutational "hotspot." 相似文献