全文获取类型
收费全文 | 408篇 |
免费 | 17篇 |
国内免费 | 4篇 |
专业分类
儿科学 | 15篇 |
妇产科学 | 4篇 |
基础医学 | 32篇 |
口腔科学 | 8篇 |
临床医学 | 92篇 |
内科学 | 56篇 |
皮肤病学 | 3篇 |
神经病学 | 12篇 |
特种医学 | 52篇 |
外科学 | 17篇 |
综合类 | 8篇 |
一般理论 | 1篇 |
预防医学 | 70篇 |
眼科学 | 9篇 |
药学 | 40篇 |
肿瘤学 | 10篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2019年 | 8篇 |
2016年 | 3篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 35篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 20篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 5篇 |
1999年 | 5篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 17篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 18篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 7篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1970年 | 3篇 |
1969年 | 8篇 |
1968年 | 6篇 |
1967年 | 5篇 |
1966年 | 9篇 |
1965年 | 2篇 |
排序方式: 共有429条查询结果,搜索用时 0 毫秒
61.
62.
63.
Vega C Guo J Killory B Danielson N Vestal M Berman R Martin L Gonzalez JL Blumenfeld H Spann MN 《Epilepsia》2011,52(8):e70-e74
Childhood absence epilepsy (CAE) has been recently linked to a number of cognitive, behavioral, and emotional disorders. Identification of affective disorders (anxiety and depression) presents unique challenges in pediatric populations, and successful early intervention may significantly improve long-term developmental outcomes. The current study examined the specific anxiety and depression symptoms children with CAE experience, and explored the role of disease factors in the severity of their presentation. Forty-five subjects with CAE and 41 healthy matched controls, ages 6-16 years, participated in the study. The Behavior Assessment System for Children (BASC) was completed by parents, and the Anxiety and Depression subscales were used to characterize problems. Item analysis within the subscales revealed that children with CAE demonstrated higher rates of symptoms of anxiety (nervousness and thought rumination) and depression (sadness and crying), as well as more general psychosocial problems including isolation and low self-esteem. Disease duration, intractability, and medication effects were not associated with higher rates of affective problems in this limited patient sample. Screening of patients with CAE for comorbid psychiatric disorders early by focusing on specific symptom profiles unique to this population may enhance overall treatment and developmental outcomes. 相似文献
64.
Kapicka CL Montamat SC Mudumbi RV Jacks SM Olson RD Vestal RE 《The Journal of pharmacology and experimental therapeutics》2000,293(2):599-606
To characterize age-related changes in beta-adrenergic responsiveness and to test the hypothesis that an increase in the effects of adenosine contribute to impaired beta-adrenergic responsiveness, Fischer 344 rat right atria (RA), left atria (LA), and left ventricular trabeculae carnae were exposed to the beta-receptor agonist isoproterenol (ISO), followed by four doses of the selective adenosine A(1) receptor agonist cyclopentyladenosine (CPA). Spontaneous contractile rates of adult RA were inhibited more than senescent RA by CPA. Contractility (+dF/dt) of adult LA was reduced more than senescent LA by CPA. Left trabeculae carnae tissue responded weakly to CPA, but senescent tissue was less responsive than adult tissue. Senescent atrial A(1) receptor density was 56% greater than in adult tissue, whereas the density in senescent ventricles was 39% lower than in adult tissue. No significant difference in antagonist affinities (K(d)) of A(1) receptor was observed between adult and senescent atria. In addition, agonist competition curves indicated a significant increase in senescent atrial and a decrease in senescent ventricular tissue in the affinity of agonist for high-affinity A(1) receptors with no difference in dissociation constant (K(i)). No significant age-related differences in atrial or ventricular tissues occurred in either the antagonist affinity (K(d)) or density (B(max)) of the beta-adrenergic receptors. CPA was found to inhibit ISO-stimulated adenylate cyclase activity more in senescent than in adult atrial and ventricular membrane preparations. We conclude that age-related differences in functional response to ISO and CPA, A(1) receptor density, and ISO-stimulated adenylate cyclase activity differ in atrial and ventricular myocardium. 相似文献
65.
H-kininogen (HK), a major factor involved in contact-phase activation, was recently immunolocalized on the external surface of human neutrophils. Experiments were, therefore, designed to consider the question of whether the complete assembly of contact factors occurs on the outer surface of the neutrophil membrane. By immunolocalization techniques, and using specific antibodies directed against the various contact factors, we now demonstrate that plasma prekallikrein (PK), factor XI (FXI), and factor XII (FXII) are present on the exterior face of the human neutrophil. Failure to localize HK, PK, or FXI by monoclonal antibodies directed to their reciprocal binding sites, and displacement of PK/FXI by peptide HK31, which mimics the relevant binding site(s) of HK, suggested that prekallikrein and FXI are anchored to the neutrophil membrane through attachment to the kininogen molecule. Probing of the kinin moiety by a specific antibody showed that kininogen molecules bound to the neutrophil cell membrane contain the kinin sequence, which can be released by plasma kallikrein or by tissue kallikrein. Our results led us to the novel conclusion that neutrophils provide a circulating platform for the components of the contact-phase system. 相似文献
66.
Regression of experimental Burkitt's lymphoma induced by Epstein-Barr virus-immortalized human B cells 总被引:3,自引:1,他引:3
Tosato G; Sgadari C; Taga K; Jones KD; Pike SE; Rosenberg A; Sechler JM; Magrath IT; Love LA; Bhatia K 《Blood》1994,83(3):776-784
Epstein-Barr virus (EBV)-immortalized human B cells survive only transiently when injected subcutaneously into athymic mice, whereas Burkitt's lymphoma cells give rise to progressively growing subcutaneous tumors. In this study, we tested whether these Burkitt's tumors could be induced to regress via a bystander effect induced by EBV-immortalized B cells. Simultaneous inoculation of EBV-immortalized B cells and Burkitt's lymphoma cells in the same subcutaneous site resulted in tumors that regressed with necrosis and scarring. Similarly, simultaneous inoculation of EBV-immortalized B cells and Burkitt's lymphoma cells in separate subcutaneous sites resulted in regression of a proportion of the Burkitt's tumors. Furthermore, most of the established human Burkitt's tumors regressed with necrosis and scarring after intratumor inoculations with EBV-immortalized B cells. The EBV-immortalized B cells continued to exert this antitumor effect even when killed with irradiation. The experimental approach to Burkitt's lymphoma treatment described here exploits the ability of athymic mice to reject EBV-immortalized B cells to target an effective antitumor response to malignant cells normally incapable of eliciting it. 相似文献
67.
M J Connolly J J Crowley C P Nielson N B Charan R E Vestal 《The American review of respiratory disease》1992,146(3):592-597
Asthma is associated with dysfunction of the beta-adrenergic receptor adenylyl cyclase signal transduction pathway. It has been argued that this results from receptor down-regulation by beta-agonist therapy. This study examined the relationship between nonspecific bronchial responsiveness (NSBR) to methacholine (Newcastle dosimeter method) and beta-adrenergic receptor density (Bmax) and affinity (%KH) in membranes from peripheral blood mononuclear leukocytes (MNL) in 12 male (27.3 +/- 1.7 yr old) and 14 female (31.4 +/- 1.7 yr old) drug-naive subjects with and without symptoms of mild intermittent wheezing. None had ever smoked or received any antiasthma medication. "Hyperresponsive" subjects were defined as those (n = 11) whose simplified slope of FEF50 (calculated as the percent fall in FEF50 divided by the dose of methacholine) was more than one SD above the mean for asymptomatic subjects. The log of the slope was reproducible (repeatability coefficient = 0.43) on two nonconsecutive days. Multiple regression analysis (overall R2 = 0.57) revealed negative relationships between the log of the slope and both Bmax (p = 0.016) and %KH (p = 0.011). Analysis of variance confirmed a lower mean (+/- SEM) value of %KH in "hyperresponsives" (45.7 +/- 5.5%) than in "normoresponsives" (60.4 +/- 4.1%, p = 0.04) with a similar trend for Bmax (hyperresponsives = 33.5 +/- 4.1 fmol/mg, normoresponsives = 45.9 +/- 7.1 fmol/mg, p = 0.18). These relationships between bronchial responsiveness, Bmax, and %KH cannot be explained by drug therapy, and they provide further evidence that there is an intrinsic impairment in the function of beta-adrenergic receptors on peripheral MNLs from subjects with high levels of nonspecific bronchial responsiveness. 相似文献
68.
Natural killer cell precursors in the CD44neg/dim T-cell receptor population of mouse bone marrow 总被引:1,自引:0,他引:1
Natural killer (NK) cells develop from the nonadherent cell component of NK long-term bone marrow (BM) cultures (NK-LTBMC). Because these nonadherent cells are depleted of mature NK cells and T cells, but appear to enriched for NK precursors, they were used as a starting population to begin to define the NK precursors that function in NK- LTBMC. As the stromal cell component of NK-LTBMC has been shown to support interleukin (IL)-2-induced, CD44 dependent, NK cell development from nonadherent NK precursors, NK-LTBMC stroma was used in a limiting dilution assay (LDA) to quantitate the precursors. NK-LTBMC in 96-well plates were irradiated (20 Gy) to kill hematopoietic cells (including the NK precursors), seeded with limiting dilutions of the cells to be quantitated, cultured with 500 U/mL IL-2 for 13 days and assayed for development of NK activity by adding 51Cr-labeled YAC-1 cells to the wells and evaluating the release of 51Cr after 4 hours. Flow cytometric analysis, sorting, and quantitation of the nonadherent cell component of NK-LTBMC showed that NK precursors were concentrated in the CD44neg/dim subset that comprised 10% of the "lymphoid" gated cells. When the CD44neg/dim subset was sorted from BM of mice treated with 5- fluorouracil (5-FU) day before (-1FUBM), there were about 30% T cells, but no NK-1.1+ cells. When the T cells were removed by sorting and the CD44neg/dim, alphabeta, gammadelta T-cell receptorneg (TCR-) subpopulation was seeded onto irradiated stroma with IL-2, they proliferated, developed NK activity, became NK-1.1+ and CD44bright and remained alphabeta, gammadelta TCR-. The frequency of NK precursors in this population as estimated from the LDA was about 1/500. 相似文献
69.
The relationship between visual development and age at eyelid separation was studied in three stocks of Peromyscus maniculatus bairdi, two stocks of P.m. gracilis, P. polionotus, and P. eremicus. The maniculatus subspecies had each been selectively bred for early and late age at eye opening. Mice were tested in a transparent chamber suspended within a rotating drum, which was lined with alternating 3/4-in. black and white vertical stripes. Beginning within 8 hr of eye opening, each mouse was given 5, 15 sec trials daily, until it responded. Criterion of vision was an optokinetic response in 2 of the 5 trials. Of 75 mice tested, only the early eye opening selected line of P. m. bairdi failed to respond on the day of eye opening. The results indicate that Peromyscus can see conspicuous environmental features at the age of eyelid separation. The delayed optokinetic response in the early selected bairdi line, requiring an average of 2.4 additional days of maturation, indicates the genetic independence of eyelid separation and visual development. The same line did not respond significantly earlier than wild type bairdi, indicating that the extra visual experience afforded by early eye opening did not increase the rate of maturation of the system (s) governing the optokinetic response. 相似文献
70.