全文获取类型
收费全文 | 3229篇 |
免费 | 163篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 43篇 |
儿科学 | 115篇 |
妇产科学 | 51篇 |
基础医学 | 319篇 |
口腔科学 | 35篇 |
临床医学 | 282篇 |
内科学 | 860篇 |
皮肤病学 | 177篇 |
神经病学 | 228篇 |
特种医学 | 248篇 |
外科学 | 472篇 |
综合类 | 37篇 |
预防医学 | 206篇 |
眼科学 | 95篇 |
药学 | 141篇 |
中国医学 | 6篇 |
肿瘤学 | 121篇 |
出版年
2022年 | 14篇 |
2021年 | 37篇 |
2020年 | 18篇 |
2019年 | 50篇 |
2018年 | 57篇 |
2017年 | 45篇 |
2016年 | 52篇 |
2015年 | 65篇 |
2014年 | 59篇 |
2013年 | 143篇 |
2012年 | 99篇 |
2011年 | 130篇 |
2010年 | 122篇 |
2009年 | 126篇 |
2008年 | 126篇 |
2007年 | 130篇 |
2006年 | 124篇 |
2005年 | 156篇 |
2004年 | 111篇 |
2003年 | 119篇 |
2002年 | 117篇 |
2001年 | 89篇 |
2000年 | 106篇 |
1999年 | 95篇 |
1998年 | 102篇 |
1997年 | 90篇 |
1996年 | 101篇 |
1995年 | 68篇 |
1994年 | 73篇 |
1993年 | 57篇 |
1992年 | 49篇 |
1991年 | 38篇 |
1990年 | 56篇 |
1989年 | 66篇 |
1988年 | 65篇 |
1987年 | 51篇 |
1986年 | 49篇 |
1985年 | 46篇 |
1984年 | 29篇 |
1983年 | 27篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 19篇 |
1978年 | 17篇 |
1977年 | 19篇 |
1976年 | 20篇 |
1975年 | 14篇 |
1973年 | 18篇 |
1965年 | 10篇 |
排序方式: 共有3436条查询结果,搜索用时 31 毫秒
81.
Myeloproliferative syndrome induced by MPSV in DBA/2 mice: presence of a mixed-colonies promoting activity (MPA) in the spleen 总被引:1,自引:0,他引:1
Le Bousse-Kerdiles MC; Smadja-Joffe F; Klein B; Jasmin C; Comisso M; Ostertag W 《Blood》1983,61(3):520-524
The myeloproliferative syndrome induced by the myeloproliferative sarcoma virus (MPSV) in DBA/2 mice stimulates the proliferation of pluripotent hemopoietic stem cells (HSC) and of progenitors committed toward granulomacrophagic and erythroid cell lines. This stimulation may result from a direct effect of the MPSV on HSC or from an indirect effect via locally secreted factors. Normal isogenic bone marrow cells were incubated in the mixed colony-forming unit system in semisolid medium supplemented with conditioned media obtained after incubating neoplastic spleen cells for 3 days at 37 degrees C. These spleen conditioned media contain an activity that is physically separable from MPSV by ultracentrifugation and which, in the presence of a very low quantity of erythropoietin, can induce in vitro the proliferation and differentiation of pluripotent HSC, detected by this Mix-CFU technique. We termed this activity mixed-colonies promoting activity (MPA). These results suggest that the hyperplasia of the nonlymphoid hematopoietic system in the neoplastic spleen results from an indirect effect of the MPSV on pluripotent HSC via locally secreted factors. 相似文献
82.
Acute administration of corticoids: a new and peculiar stimulus of growth hormone secretion in man 总被引:4,自引:0,他引:4
F F Casanueva B Burguera C Muruais C Dieguez 《The Journal of clinical endocrinology and metabolism》1990,70(1):234-237
It is widely accepted that chronic administration of corticoids in man inhibits the GH response to all of the stimuli tested so far. To study the action of corticoids administered acutely, several dexamethasone challenge tests were performed, after which GH levels were measured for 7 h. In eight volunteers, administration of 4 mg dexamethasone (Dex), iv, induced a clear-cut GH release compared with saline administration. The secretion followed an unusual pattern; basal GH levels (1.5 +/- 0.1 micrograms/L) started rising 2 h after Dex injection, reaching a peak of 17.5 +/- 4.4 micrograms/L after 3 or 3.5 h. Peak levels were maintained until 5 h post-Dex and decreased thereafter. Similar data were obtained when Dex was administered to five volunteers at the dose of 8 mg, orally, with a 30-min delay of the GH peak (19.6 +/- 7.9 micrograms/L). To study whether there was a cholinergic input responsible for the Dex action, another group of eight volunteers underwent three Dex tests (4 mg, iv) on three occasions, followed 90 min later by the administration of placebo (control), atropine (0.5 mg, iv), or pyridostigmine (120 mg, orally). The Dex-induced GH peak (20.8 +/- 5.2 micrograms/L) was not significantly increased by pyridostigmine (cholinergic agonist) treatment (24.2 +/- 4.0 micrograms/L). The blockade of muscarinic receptors by atropine induced a delay in the Dex-induced secretory peak, which appeared at 5 h. However, the Dex-atropine GH peak (14.9 +/- 4.1 micrograms/L) was not different from the Dex-placebo one. In conclusion, Dex alone is able to induce a clear-cut GH secretion in man. The stimulus followed a peculiar time pattern, with peaks levels attained 3 h after either iv or oral administration. 相似文献
83.
Phase I trial of interleukin-2 after unmodified HLA-matched sibling bone marrow transplantation for children with acute leukemia 总被引:1,自引:1,他引:1
Robinson N; Sanders JE; Benyunes MC; Beach K; Lindgren C; Thompson JA; Appelbaum FR; Fefer A 《Blood》1996,87(4):1249-1254
Allogeneic bone marrow transplantation (BMT) for advanced acute leukemia is associated with a high risk of relapse. It is postulated that interleukin-2 (IL-2) administered after BMT might induce or amplify a graft-versus-leukemia effect and thereby reduce the relapse rate. To identify an IL-2 regimen for testing this hypothesis, a phase I trial of IL-2 (Roche) was performed in children in complete remission (CR) without active graft-versus-host disease (GVHD) off immunosuppressive agents after unmodified allogeneic matched-sibling BMT for acute leukemia beyond first remission. Beginning a median of 68 days after BMT, 17 patients received escalating doses of induction IL-2 (0.9, 3.0, or 6.0 x 10(6) IU/m2/d representing levels I, II, and III) for 5 days by continuous intravenous infusion (CIV). After 6 days of rest, they received maintenance IL-2 (0.9 x 10(6) IU/m2/d) for 10 days by CIV infusion. Levels I and II were well-tolerated, but, of 6 patients at level III, 1 developed pulmonary infiltrates, 1 developed hypotension (both resolved), and 1 died of bacterial sepsis and acute respiratory distress syndrome. Grade II acute GVHD developed in 1 patient at level I and 1 at level III. The maximum tolerated dose of induction IL-2 was level II. IL-2 induced lymphocytosis, with an increase in CD56+ and CD8+ cells. Ten patients remain in CR at 5+ to 67+ months. Thus, a regimen of IL-2 has been identified that did not induce a high incidence of acute GVHD when administered to children after unmodified allogeneic BMT. Its clinical activity will be assessed in a phase II trial. 相似文献
84.
85.
Karl Pillemer Emily K. Chen Catherine Riffin Holly Prigerson MC Reid Leslie Schultz 《American journal of public health》2015,105(11):2237-2244
We employed the research-to-practice consensus workshop (RTP; workshops held in
New York City and Tompkins County, New York, in 2013) model to merge researcher
and practitioner views of translational research priorities in palliative care.
In the RTP approach, a diverse group of frontline providers generates a research
agenda for palliative care in collaboration with researchers. We have presented
the major workshop recommendations and contrasted the practice-based research
priorities with those of previous consensus efforts. We uncovered notable
differences and found that the RTP model can produce unique insights into
research priorities. Integrating practitioner-identified needs into research
priorities for palliative care can contribute to addressing palliative care more
effectively as a public health issue.Over the past 2 decades, palliative care has become established as a promising approach
for addressing the needs of individuals with life-threatening illnesses from a holistic,
interdisciplinary perspective. For this project, we defined palliative care as an
approach that improves the quality of life of patients and families facing the problems
encountered in life-threatening illness by preventing and relieving suffering. Core
components of palliative care include providing relief from pain and other distressing
symptoms, affirming dying as a normal process, integrating psychological and spiritual
aspects of care, enhancing the quality of life of patients, and offering support systems
to patients and their families to help them live as fully as possible until death
occurs.Research suggests that palliative care results in positive patient outcomes, greater
patient and family satisfaction, and significant cost savings.1,2 The American Public Health Association, the
World Health Organization, and the Institute of Medicine3–6 have identified the
development of a robust palliative care delivery system as a key public health issue
because of the documented ability of palliative care to deliver effective and efficient
patient- and symptom-focused care to a growing population in need.In its 2013 report the American Public Health Association specifically detailed the
public health implications of palliative care, acknowledged the growing burden of
advanced chronic illness and disease in older adults, and recommended key steps to
address the problem. This policy statement called for federal, state, and local efforts
to promote effective symptom management in populations with serious illness or at the
end of life. Other recommended initiatives included the development of a palliative care
workforce, educational programs to improve uptake and use of palliative and hospice
care, and research funding to support the expansion of palliative care initiatives.
Achieving these goals will require moving beyond traditional medical practices to
include both policies and initiatives at the public health level.Despite the potential of palliative care to address the mental and physical health needs
of individuals with advanced illness, significant knowledge gaps impede its reach and
effectiveness. Reports from scientific bodies and consensus workshops have highlighted
weaknesses in the literature and called for more research on palliative care and
improved research methods.7–10 Thus, although both interest in and demand for
palliative care are increasing, reviews of the knowledge base continue to lament the
lack of research on many key issues.11,12Especially urgent is a research agenda that fits most closely with the needs of providers
who deliver palliative care. The systematic engagement of community practitioners in a
consensus process can lead to particularly useful and actionable recommendations for
research,13–15 which are greatly needed at this stage in the
development of the field. Therefore, to shed new light on research priorities in
palliative care, we used a structured, participatory method designed to solicit
practitioner input on research priorities: the research-to-practice consensus workshop
(RTP) model.16We employed the RTP approach to identify knowledge gaps and types of studies that should
be conducted to improve providers’ ability to deliver palliative care most
effectively. This model harnesses practice wisdom by engaging clinicians, agency staff,
and other practitioners with researchers in a process of articulating and refining
research questions and research priorities that honors scientific expertise and practice
wisdom. 相似文献
86.
BAX and BCL‐2 polymorphisms,as predictors of proliferative vitreoretinopathy development in patients suffering retinal detachment: the Retina 4 project
下载免费PDF全文
![点击此处可从《Acta ophthalmologica. Supplement》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Salvador Pastor‐Idoate Irene Rodríguez‐Hernández Jimena Rojas Itziar Fernández María‐Teresa García‐Gutierrez Jose M. Ruiz‐Moreno Amandio Rocha‐Sousa Yashin D. Ramkissoon Steven Harsum Robert E. MacLaren David G. Charteris Jan C. Van Meurs Rogelio González‐Sarmiento Jose C. Pastor the Genetics on PVR Study Group 《Acta ophthalmologica. Supplement》2015,93(7):e541-e549
87.
Embryonic tissues were obtained from normal (C) and thyroidectomized (T) rats between 9 and 21 days of pregnancy. We determined the number and weight, as well as the T4 and T3 contents (RIA), of 9- to 12-day-old embryotrophoblasts, of 13- to 21-day-old embryos and placentas, and of liver, lung, and brain from 20- and 21-day-old fetuses. T4 and T3 were found in all samples obtained from C dams, both before and after onset of fetal thyroid function. Despite low levels of both iodothyronines in fetal plasma near term, their concentrations in fetal brain and lung had reached half the maternal values. The T3/T4 ratio in fetal organs was the same, or higher, than in adult rats. Maternal thyroidectomy resulted in a marked decrease of the number and individual weights of viable conceptuses, throughout gestation. Fetal organ weights near term were also decreased, and changes were found in brain DNA and protein concentrations. T4 and T3 were undetectable in all embryotrophoblasts, embryos and placentas obtained from T dams before onset of fetal thyroid secretion. They were still markedly reduced in 21-day-old placentas. Total extrathyroidal contents of T3 and T4 in 20- and 21-day-old fetuses from T dams were also low as compared to those from normal mothers, but individual organs were not affected to the same degree. Thus concentrations were decreased in the carcass (whole embryo minus the trachea + thyroid + liver + lung + brain), but normal in the brain. These results show that maternal hypothyroidism is accompanied by thyroid hormone deficiency of the conceptus before the fetal thyroid functions. After this, alterations of T4 and T3 concentrations persist until term. Development is also delayed. Thus, adverse effects of maternal hypothyroidism may be due, at least in part, to the thyroid hormone deficiency of the embryonic tissues, and not only to the hypothyroid condition of the mother. 相似文献
88.
89.
Attenuated response to purified protein derivative in patients with rheumatoid arthritis: study in a population with a high prevalence of tuberculosis
下载免费PDF全文
![点击此处可从《Annals of the rheumatic diseases》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ponce de León D Acevedo-Vásquez E Sánchez-Torres A Cucho M Alfaro J Perich R Pastor C Harrison J Sánchez-Schwartz C 《Annals of the rheumatic diseases》2005,64(9):1360-1361
BACKGROUND: The purified protein derivative (PPD) skin test is the only widely used method which detects latent tuberculosis infection (LTBI) and is dependent on a normal T cell function. In rheumatoid arthritis (RA) the T cell function is altered, which may result in an inability to develop an adequate PPD reaction. OBJECTIVES: To evaluate the response to PPD in patients with RA and to compare it with that of control subjects. METHODS: 112 patients with RA and 96 healthy controls were studied. PPD 5 U was applied using the Mantoux method, and skin reaction was measured at 72 hours. The reaction was considered negative for PPD <5 mm. RESULTS: There were no significant differences in age, sex, history of bacille Calmette-Guerin vaccination, or tuberculosis contact between the two groups. The median size of the PPD induration in the patients with RA was significantly less than that in the control group (4.5 v 11.5 mm, p<0.01). 79 (70.6%) patients with RA compared with 25 (26%) of the control group had a negative reaction to PPD (p<0.01), a response not influenced by disease activity or duration of disease in the patients with RA. CONCLUSION: A PPD skin test is not an appropriate test for recognising LTBI in patients with RA in our population. 相似文献
90.
Martínez-Borra J López-Larrea C González S Fuentes D Dieguez A Deschamps EM Pérez-Pariente JM López-Vázquez A de Francisco R Rodrigo L 《The American journal of gastroenterology》2002,97(9):2350-2356
OBJECTIVES: Infliximab, a chimeric monoclonal antibody directed against tumor necrosis factor-alpha (anti-TNF-alpha), has been effective in the treatment of patients with active Crohn's disease and with fistulas. We investigated the effect of infliximab on circulating cytokines and acute phase proteins in patients with fistulas to determine the clinical response to anti-TNF-alpha. METHODS: A total of 36 patients with fistulizing Crohn's disease were selected for study. Serum from patients was drawn before the infusion on day 0 and at wk 2, 4, 6, 8, and 10 after completion of treatment. Circulating concentrations of TNF-alpha, interleukin-1beta (IL-1beta), and IL-6 were measured by ELISA. The functional activity of circulating TNF-alpha was assessed by the WEHI 164 TNF-alpha bioassay. Acute phase proteins were also determined. RESULTS: Elevated TNF-alpha, IL-1beta, IL-6, and acute phase proteins were observed in patients with Crohn's disease. Of the patients with fistulas, 22 (61.1%) responded to treatment. Before receiving infliximab, higher levels of serum TNF-alpha were found in patients who did not respond to infliximab compared with those who did (median interquartile range 26, 0-245 pg/ml; n = 14 vs 0, 0-22 pg/ml, n = 22). Patients showed no change in circulating levels of TNF-alpha during the course of the study. CONCLUSIONS: This treatment produces a clinical improvement in about two-thirds of CD patients with fistulas. The circulating levels of TNF-alpha are associated with the response to infliximab and could help to identify patients who would benefit from anti-TNF-alpha treatment. 相似文献