全文获取类型
收费全文 | 1718篇 |
免费 | 189篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 93篇 |
妇产科学 | 55篇 |
基础医学 | 233篇 |
口腔科学 | 19篇 |
临床医学 | 199篇 |
内科学 | 290篇 |
皮肤病学 | 31篇 |
神经病学 | 197篇 |
特种医学 | 120篇 |
外科学 | 341篇 |
综合类 | 40篇 |
预防医学 | 130篇 |
眼科学 | 14篇 |
药学 | 86篇 |
中国医学 | 2篇 |
肿瘤学 | 61篇 |
出版年
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 14篇 |
2014年 | 27篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 51篇 |
2010年 | 53篇 |
2009年 | 54篇 |
2008年 | 70篇 |
2007年 | 87篇 |
2006年 | 69篇 |
2005年 | 85篇 |
2004年 | 52篇 |
2003年 | 67篇 |
2002年 | 62篇 |
2001年 | 49篇 |
2000年 | 63篇 |
1999年 | 70篇 |
1998年 | 43篇 |
1997年 | 57篇 |
1996年 | 44篇 |
1995年 | 34篇 |
1994年 | 41篇 |
1993年 | 31篇 |
1992年 | 45篇 |
1991年 | 42篇 |
1990年 | 53篇 |
1989年 | 55篇 |
1988年 | 52篇 |
1987年 | 47篇 |
1986年 | 38篇 |
1985年 | 35篇 |
1984年 | 20篇 |
1983年 | 16篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 21篇 |
1979年 | 20篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1976年 | 13篇 |
1975年 | 19篇 |
1974年 | 11篇 |
1973年 | 8篇 |
1972年 | 11篇 |
1970年 | 11篇 |
1968年 | 9篇 |
排序方式: 共有1914条查询结果,搜索用时 15 毫秒
991.
992.
993.
BACKGROUND: CAY-1 is a fungicidal saponin from cayenne pepper whose mode of action differs from amphotericin B (AB) and itraconazole (IT). This work determined CAY-1 synergism with AB or IT. METHODS: CAY-1 was purified and used in checkerboard microdilution studies where CAY-1 and AB or IT were mixed with nongerminated (NG) and germinating (G) conidia of three Aspergillus species and Candida albicans. Inhibition was visually determined at 24 and 48 h. RESULTS: CAY-1 had predominantly additive-synergistic interaction with AB or IT against the Aspergillus NG and G conidia. Excellent synergy between CAY-1 and AB occurred at 24 and 48 h against C. albicans. Results suggest CAY-1 enhances AB and IT efficacy. 相似文献
994.
Methylmercury induces activation of Notch signaling 总被引:1,自引:0,他引:1
Methylmercury (MeHg) toxicity in humans manifests deficits in neurological function. Cases of prenatal exposure to mercury have established that the developing nervous system is most highly susceptible to perturbation by MeHg. At a cellular level, MeHg-induced defects result from altered neuronal proliferation, migration and pathfinding. However, the molecular targets of MeHg that give rise to these outcomes are not fully understood. In an overall effort to identify the fundamental molecular targets of MeHg in neural development, we have explored the effects of MeHg on cell surface receptor function using the simplified Drosophila model. In this study, we investigated the potential role of MeHg to alter activity of the Notch receptor pathway, a highly conserved cell-cell signaling mechanism that controls cell fate decisions, proliferation, migration and neurite outgrowth in neural development. Notch receptor activation requires proteolysis by a cell surface ADAM metalloprotease. ADAM proteases are required for normal neural development and are activated by organomercurials, thus presenting a possible mechanism for MeHg neurotoxicity. Here, we demonstrate a concentration- and time-dependent increase in Notch receptor activity with MeHg exposure in three distinct Drosophila cell lines. Ten micromolar MeHg results in a 4-5.5-fold increase in Notch signaling as measured by the upregulation of two enhancer of split (E(spl)) target genes. MeHg-induced Notch activity also correlates with receptor proteolysis. Targeted knockdown of Notch protein expression demonstrates that MeHg induced E(spl) activation specifically requires the Notch receptor. Furthermore, MeHg-induced Notch activity is partially attenuated by the metalloprotease inhibitor, GM6001, consistent with a model in which MeHg promotes activation of ADAM metalloproteases. Finally, we demonstrate that inorganic HgCl(2) is significantly less active in inducing Notch activity, suggesting a mechanism specific to organic species of mercury. Overall, these data identify Notch as a potential target for MeHg toxicity in the developing nervous system. 相似文献
995.
Evidence has accumulated suggesting that the median raphe (MR) mediates hippocampal theta desynchronization. However, few studies have evaluated theta-related neural circuitry during MR manipulation. In urethane-anesthetized rats, we investigated the effects of MR stimulation on hippocampal field and cell activity using high-frequency (100 Hz), theta burst (TBS), and slow-frequency electrical stimulation (0.5 Hz). We demonstrated that high-frequency stimulation of the MR did not elicit deactivated patterns in the forebrain, but rather elicited low-voltage activity in the neocortex and small-amplitude irregular activity (SIA) in the hippocampus. Both hippocampal phasic theta-on and -off cells were inhibited by high-frequency MR stimulation, although MR stimulation failed to affect cells that had neither state or phase relationships with theta field activity. TBS of the MR-induced theta field activity phase locked to the stimulation. Slow-frequency stimulation elicited a state-dependent reset of theta phase through a short-latency inhibition (5 ms) in phasic theta-on cells. Subpopulations of phasic theta-on cells responded in either oscillatory or nonoscillatory patterns to MR pulses, depending on their intraburst interval. off cells exhibited a state-dependent modulation of cell firing occurring preferentially during nontheta. The magnitude of MR-induced reset varied as a function of the phase of the theta oscillation when the pulse was administered. Therefore high-frequency stimulation of the MR appears to disrupt hippocampal theta through a state-dependent, short-latency inhibition of rhythmic cell populations in the hippocampus functioning to switch theta oscillations to an activated SIA field state. 相似文献
996.
Kimberly J. Waddell Rebecca L. Birkenmeier Marghuretta D. Bland 《Disability and rehabilitation》2016,38(9):853-857
Purpose: To classify the self-identified goals of individuals post-stroke with chronic upper extremity (UE) paresis, and determine if age, UE functional capacity and pre-stroke hand dominance influence overall goal selection. Method: Sixty-five subjects participated. Using the Canadian Occupational Performance Measure (COPM) to establish treatment goals, the top five goals were categorized using the Occupational Therapy Practice Framework into five categories: activities of daily living (ADLs), instrumental activities of daily living (IADLs), leisure, work and general UE movement. A Chi-square analysis determined if age, UE functional capacity (measured by the Action Research Arm Test) and UE hand dominance influenced individual goal selection. Results: The majority of goals were in the ADL (37%) and IADL (40%) categories. A small percentage (12%) was related to general UE movement. Individuals with moderate UE functional capacity identified more ADL goals than those with higher UE functional capacity. There was not a difference between age and UE dominance across all five goal areas. Conclusions: Individuals with chronic UE paresis had specific goals that were not influenced by age or hand dominance, but partially influenced by severity. General UE movement goals were identified less than goals related to specific activities.
- Implications for Rehabilitation
Considering the specificity of individual goals following stroke, it is recommended that clinicians regularly utilize a goal setting tool to help establish client goals.
It is recommended that clinicians further inquire about general goals in order to link upper extremity deficits to functional activity limitations.
Age, upper extremity functional capacity and hand dominance have little influence on the rehabilitation goals for individuals with chronic paresis after stroke.
997.
Pool AJ Whipp BJ Skasick AJ Alavi A Bland JM Axford JS 《Rheumatology (Oxford, England)》2004,43(1):43-48
OBJECTIVE: To investigate muscle energetics in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and measure serum cortisol, prolactin and CD4+/CD8+ T-cell levels during and after controlled exhaustive exercise. METHODS: Patients with RA (n = 7), patients with SLE (n = 6) and healthy individuals (HI) (n = 10) performed incremental cycle ergometry to the limit of tolerance. Ventilation, oxygen uptake (VO2) and carbon dioxide output were measured and the lactate threshold (LT) was estimated. Serum cortisol, prolactin, CD4+ and CD8+ lymphocyte subset levels were determined at baseline, peak exercise and 1 h after exercise. RESULTS: Exercise tolerance was reduced in patients with RA and patients with SLE, as reflected by peak VO2 and LT, but muscle energetics were not altered. In RA and SLE, there was significant reduction in cortisol levels at peak (-10%; P = 0.03) and post-exercise times (-36%; P = 0.05). Prolactin varied significantly at peak exercise in HI only (+60%; P = 0.05). There was a significant reduction in CD4+ T cells at peak exercise in RA (-15%; P = 0.02) and SLE patients (-8%; P = 0.04) and an increase after exercise in SLE patients (+11%; P = 0.03). In HI, CD8+ T cells increased significantly (+47%; P = 0.01) at peak exercise, but this was not found in RA and SLE patients. A significant reduction in CD8+ T cells was noted after exercise in SLE patients (-6%; P = 0.05). CONCLUSION: RA and lupus patients do not have significantly altered muscle energetics, but have abnormal cortisol, prolactin and CD4+/CD8+ T-cell responses to exercise. Further studies need to be carried out to evaluate whether short bouts of strenuous exercise have detrimental clinical effects. 相似文献
998.
Dietary n-3 polyunsaturated fatty acids reduce disease and colonic proinflammatory cytokines in a mouse model of colitis 总被引:2,自引:0,他引:2
BACKGROUND: n-3 polyunsaturated fatty acids (PUFAs) reduce the severity of chronic inflammatory bowel disease, probably by means of reduction of immune cell activation or enhancement of the epithelial barrier. Using the severe combined immunodeficient (SCID) mouse model of colitis, this study examined the effect of dietary n-3 PUFAs on development of colitis and on immunologic, epithelial, and matrix parameters in the intestines of control and colitic animals. METHODS: SCID mice were fed n-3-enriched or control diet for 3 weeks before colitis induction by transplantation of CD45RB T cells and maintained on the same diet for 4 to 8 weeks. Phenotype of infiltrating cells, epithelial ZO-1 protein, and mucosal type I collagen were assessed by immunohistology and tissue cytokines by ELISA. RESULTS: Transplanted n-3-fed animals had significantly reduced pathology scores, colonic tumor necrosis factor-alpha, interleukin-12, and interleukin-1beta compared with animals fed standard diet. Proinflammatory cytokines were reduced despite a similar level of immune cell infiltration by T cells, CD11c cells, and CD11b cells. Neutrophil infiltration was significantly reduced in n-3-fed control and colitic mice, and other myeloid populations were reduced in mice on the n-3 diet. Epithelial ZO-1 expression was increased, and myofibroblast activation significantly decreased in transplanted n-3-fed animals compared with standard diet mice. Submucosal collagen synthesis was enhanced in n-3-fed mice. CONCLUSIONS: Dietary n-3 PUFAs reduced clinical colitis and colonic immunopathology in this model of colonic inflammation by decreasing proinflammatory cytokine synthesis, reducing myeloid cell recruitment and activation, and enhancing epithelial barrier function and mucosal wound healing mechanisms. 相似文献
999.
Cecal ligation and puncture 总被引:1,自引:0,他引:1
Hubbard WJ Choudhry M Schwacha MG Kerby JD Rue LW Bland KI Chaudry IH 《Shock (Augusta, Ga.)》2005,24(Z1):52-57
The model of cecal ligation and puncture (CLP) in rodents has been used extensively to investigate the clinical settings of sepsis and septic shock. This model produces a hyperdynamic, hypermetabolic state that can lead to a hypodynamic, hypometabolic stage, and eventual death. Blood cultures are positive for enteric organisms very early after CLP. The model has been widely used over the past 26 years and is highly versatile in adapting to a range of severity and testing objectives. It is inexpensive to prepare and technically straightforward. Aspects of sepsis research investigated using CLP include energetics, metabolism, resuscitation, antibiotic therapy, microbial factors, cardiovascular responses, immune function, mediator release, and cytokine expression patterns. The challenge of the small circulating blood volume in rodents can be overcome by using micromethods that enable analysis of small volumes, or alternatively, by using a large number of animals to obtain serial samples. 相似文献
1000.
Some nurses describe individuals diagnosed with borderline personality disorder (BPD) as among the most challenging and difficult patients encountered in their practice. As a result, the argument has been made for nursing staff to receive clinical supervision to enhance therapeutic effectiveness and treatment outcomes for individuals with BPD. Formal clinical supervision can focus on the stresses of working in a demanding environment within the work place and enable nurses to accept accountability for their own practice and development (Pesut & Herman, 1999). A psychiatric-mental health clinical nurse specialist can provide individual and/or group supervision for the nursing staff, including education about patient dynamics, staff responses, and treatment team decisions. A clinical nurse specialist also can provide emotional support to nursing staff, which enhances job satisfaction, as they struggle to maintain professional therapeutic behavior with these individuals. 相似文献