全文获取类型
收费全文 | 32715篇 |
免费 | 1848篇 |
国内免费 | 101篇 |
专业分类
耳鼻咽喉 | 253篇 |
儿科学 | 1173篇 |
妇产科学 | 942篇 |
基础医学 | 3696篇 |
口腔科学 | 404篇 |
临床医学 | 5878篇 |
内科学 | 5737篇 |
皮肤病学 | 349篇 |
神经病学 | 3147篇 |
特种医学 | 610篇 |
外国民族医学 | 1篇 |
外科学 | 3085篇 |
综合类 | 299篇 |
现状与发展 | 1篇 |
一般理论 | 50篇 |
预防医学 | 4473篇 |
眼科学 | 447篇 |
药学 | 1887篇 |
中国医学 | 33篇 |
肿瘤学 | 2199篇 |
出版年
2023年 | 195篇 |
2022年 | 330篇 |
2021年 | 605篇 |
2020年 | 435篇 |
2019年 | 665篇 |
2018年 | 811篇 |
2017年 | 566篇 |
2016年 | 641篇 |
2015年 | 676篇 |
2014年 | 1001篇 |
2013年 | 1616篇 |
2012年 | 2320篇 |
2011年 | 2458篇 |
2010年 | 1301篇 |
2009年 | 1154篇 |
2008年 | 2234篇 |
2007年 | 2421篇 |
2006年 | 2316篇 |
2005年 | 2245篇 |
2004年 | 2058篇 |
2003年 | 1983篇 |
2002年 | 1890篇 |
2001年 | 239篇 |
2000年 | 219篇 |
1999年 | 311篇 |
1998年 | 389篇 |
1997年 | 316篇 |
1996年 | 258篇 |
1995年 | 280篇 |
1994年 | 228篇 |
1993年 | 215篇 |
1992年 | 158篇 |
1991年 | 164篇 |
1990年 | 168篇 |
1989年 | 138篇 |
1988年 | 122篇 |
1987年 | 112篇 |
1986年 | 116篇 |
1985年 | 130篇 |
1984年 | 137篇 |
1983年 | 136篇 |
1982年 | 151篇 |
1981年 | 144篇 |
1980年 | 123篇 |
1979年 | 63篇 |
1978年 | 77篇 |
1977年 | 70篇 |
1976年 | 49篇 |
1975年 | 38篇 |
1974年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Linda Laatsch Thomas Jobe Jerry Sychra Qing Lin Michael Blend 《Brain injury : [BI]》1997,11(12):851-864
Three patients,with known brain injury and neuropsychological impairments, are followed through an individualized cognitive rehabilitation programme and post discharge from the treatment programme. Single Photon Emission Computed Tomography (SPECT) of the brain was employed to evaluate resting relative cerebral blood flow (rCBF) during the process of recovery from brain injury. All patients experienced significant improvements on measures of neuropsychological functioning and improvements in rCBF during this longitudinal study. The specific changes in rCBF appear to be related to the location of the patient s brain injury and strategies particular to cognitive rehabilitation therapy. Continued improvements in rCBF, functional abilities, and cognitive skills were documented in these three cases up to 45 months post brain injury. 相似文献
43.
F. Fabris I. Cordiano F. Salvan R. Ramon M. Valente G. Luzzatto A. Girolami 《European journal of haematology》1997,58(1):40-45
Abstract: We studied 47 subjects belonging to 13 unrelated families with a history of mild haemorrhagic diathesis and chronic thrombocytopenia. 36 patients presented some degree of thrombocytopenia: 7/36 (19%) had slight thrombocytopenia (100–150×109/L); 26/36 (72%) had mild thrombocytopenia (50–100×109/L) and 3/36 (8%) had severe thrombocytopenia (<50×109/L). No correlation was observed between platelet count and the degree of haemorrhagic diathesis, which was mild in the majority of patients. Transmission was autosomal dominant. Platelet anisocytosis, increased percentage of large platelets and absence of leukocyte inclusions were observed in 26/30 (87%) of the examined blood smears. The ultrastructural appearance of platelets was normal. Megakaryocytes appeared normal in number in 10/10 patients, but showed asynchronous nuclear-cytoplasm maturation and mainly nonlobulated nuclei. Platelet aggregation was studied in 26 patients and either increased or decreased curves were variably observed in response to different aggregating agents. Platelet-associated IgG (PAIgG) was increased in 18/31 (58%) patients, while serum autoantibodies against platelet glycoproteins Ib/IX or IIb/IIIa were demonstrable in only 1 case. An increased expression of platelet surface glycoproteins Ib and IIb/IIIa, as studied by murine monoclonal antibodies binding in 17 cases, was observed. Platelet survival performed by 111In-oxine-labelled autologous platelets was normal in the 3 studied patients. Congenital macrothrombocytopenia confirms to be a distinct clinical disorder for which the name of “chronic isolated hereditary macrothrombocytopenia” is proposed. 相似文献
44.
Dr. Seema A. Khan MD Nick J. Gonchoroff DrPH Linda E. Miller PhD 《Annals of surgical oncology》1997,4(6):462-469
Background: Many studies have addressed the effect of the timing of surgery for breast cancer relative to menstrual cycle phase, with
conflicting results. Explanations for the possibility that survival could be altered by the appropriate timing of breast cancer
surgery in humans remain speculative.
Methods: We examined the expression of three estrogen related proteins (c-erbB-2, cathepsin D, pS2) in the breast tumors from 69 premenopausal women sampled in different phases of the menstrual cycle.
Data on S-phase fraction and hormone receptor expression were also analyzed. Immunohistochemical assays were used to measure
the proteins of interest. S-phase fraction was determined by flow cytometry. Analyses were performed based on fraction of
cells staining positive for the protein, density of stain, and a histoscore that combined both fraction of positive cells
and density.
Results: We found no differences in c-erbB-2, cathepsin D, hormone receptor, or S-phase levels in tumors sampled in the follicular versus luteal phase, or perimenstrual
versus periovulatory phase. The exception was pS2, which was expressed at greater levels during the luteal than during the
follicular phase of the cycle (p<0.01); but there was no difference in pS2 expression when the patients were classified as
periovulatory versus perimenstrual.
Conclusions: Our findings do not support a variation in c-erbB-2, cathepsin D, S-phase fraction, or receptor expression as an explanation for the differences in breast cancer prognosis
when surgery is timed by menstrual cycle phase. The finding that pS2 (an indicator of hormone sensitivity, and possibly better
prognosis) is expressed at higher levels in tumor samples during the luteal phase suggests that the biologic profile of breast
tumors may vary with the menstrual cycle and that these variations deserve further study. 相似文献
45.
Nancy D. Brener Etienne G. Krug Linda L. Dahlberg Kenneth E. Powell 《The Journal of school health》1997,67(5):171-174
ABSTRACT: Programs for preventing violence among youth should be evaluated to determine if they are effective. Nurses' logs appear to be a useful tool for evaluating school-based violence prevention programs. The logs provide a record of students' visits to the school nurse that can be used to determine if a violence prevention program is associated with a reduction in fighting—and other injury-related nurse visits. This method has many strengths: it is simple and inexpensive, it does not interrupt the school routine, it permits school-level rather than student-level data collection, it provides a ready "baseline," and it allows continuous data collection. However, potential limitations do exist. For example, the method may provide insufficient information and may be affected by factors unrelated to the intervention. School officials can increase the usefulness of the logs by encouraging standardization and providing training in their use. 相似文献
46.
Increased incidence of gap junctional coupling between spinal motoneurones following transient blockade of NMDA receptors in neonatal rats 总被引:3,自引:0,他引:3
George Z. Mentis Eugenia Díaz Linda B. Moran Roberto Navarrete 《The Journal of physiology》2002,544(3):757-764
Neonatal rat motoneurones are electrically coupled via gap junctions and the incidence of this coupling declines during postnatal development. The mechanisms involved in this developmental regulation of gap junctional communication are largely unknown. Here we have studied the role of NMDA receptor-mediated glutamatergic synaptic activity in the regulation of motoneurone coupling. Gap junctional coupling was demonstrated by the presence of graded, short latency depolarising potentials following ventral root stimulation, and by the transfer of the low molecular weight tracer Neurobiotin to neighbouring motoneurones. Sites of close apposition between the somata and/or dendrites of the dye-coupled motoneurones were identified as potential sites of gap junctional coupling. Early postnatal blockade of the NMDA subtype of glutamate receptors using the non-competitive antagonist dizocilpine maleate (MK801) arrested the developmental decrease in electrotonic and dye coupling during the first postnatal week. These results suggest that the postnatal increase in glutamatergic synaptic activity associated with the onset of locomotion promote the loss of gap junctional connections between developing motoneurones. 相似文献
47.
48.
Linda G. Rabinowitz M.D. Nancy B Esterly M.D. Ilona J. Frieden M.D. Gregory S. Garbin M.D. Roy C. Grekin M.D. T. J. Stafford M.D. Ph.D. O. T. Tan M.D. Linda G. Rabinowitz M.D. Gerald N. Goldberg M.D. Karen F Rothman M.D. Lynne J. Roberts M.D. Roy G. Geronemus M.D. Susan B. Mallory M.D. Jerome M. Garden M.D. Joseph G. Morelli M.D. Moise L Levy M.D. Bernard A. Cohen M.D. 《Pediatric dermatology》1992,9(2):132-153
One of the most exciting developments in pediatric dermatology has been the use of the flashlamp-pumped, 585-nm, pulsed dye laser for treatment of vascular birthmarks. In many cases the results are miraculous. The increase in self-esteem and happiness of many children and adolescents has been overwhelming; for some, depression has been lifted, stuttering has ceased, social involvement has increased, and antidepressants have been discontinued. There are many success stories to tell.
Despite the remarkable effects of the pulsed dye laser and the medical and psychosocial indications for its use, the issue of pain control remains significant. We have no perfect outpatient pediatric anesthetic. Most methods carry either some risk or, if not hazardous, often are not very effective for controlling pain. Needless to say, a diversity of opinions exist on how to manage discomfort from this treatment modality. Therefore, we thought it would be useful to share the experiences and opinions of several dermatologists who have extensive experience with the pulsed dye laser. 相似文献
Despite the remarkable effects of the pulsed dye laser and the medical and psychosocial indications for its use, the issue of pain control remains significant. We have no perfect outpatient pediatric anesthetic. Most methods carry either some risk or, if not hazardous, often are not very effective for controlling pain. Needless to say, a diversity of opinions exist on how to manage discomfort from this treatment modality. Therefore, we thought it would be useful to share the experiences and opinions of several dermatologists who have extensive experience with the pulsed dye laser. 相似文献
49.
The spinal cord dorsal horn contains neural mechanisms which can greatly facilitate pain. We have recently shown that ‘illness’-inducing agents, such as intraperitoneally administered lipopolysaccharide (LPS; bacterial endotoxin), can produce prolonged hyperalgesia. This hyperalgesic state is mediated at the level of the spinal cord via activation of the NMDA-nitric oxide cascade. However, prolonged neuronal depolarization is required before such a cascade can occur. The present series of experiments were aimed at identifying spinal neurotransmitters which might be responsible for creating such a depolarized state. These studies show that LPS hyperalgesia is mediated at the level of the spinal cord by substance P, cholecystokinin and excitatory amino acids acting at non-NMDA sites. No apparent role for serotonin or kappa opiate receptors was found. 相似文献
50.