全文获取类型
收费全文 | 8609篇 |
免费 | 848篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 218篇 |
妇产科学 | 268篇 |
基础医学 | 1164篇 |
口腔科学 | 124篇 |
临床医学 | 784篇 |
内科学 | 1970篇 |
皮肤病学 | 130篇 |
神经病学 | 883篇 |
特种医学 | 279篇 |
外科学 | 1170篇 |
综合类 | 263篇 |
一般理论 | 6篇 |
预防医学 | 561篇 |
眼科学 | 194篇 |
药学 | 537篇 |
中国医学 | 37篇 |
肿瘤学 | 806篇 |
出版年
2023年 | 66篇 |
2022年 | 107篇 |
2021年 | 244篇 |
2020年 | 185篇 |
2019年 | 251篇 |
2018年 | 245篇 |
2017年 | 174篇 |
2016年 | 201篇 |
2015年 | 256篇 |
2014年 | 323篇 |
2013年 | 386篇 |
2012年 | 554篇 |
2011年 | 564篇 |
2010年 | 310篇 |
2009年 | 278篇 |
2008年 | 467篇 |
2007年 | 449篇 |
2006年 | 444篇 |
2005年 | 392篇 |
2004年 | 376篇 |
2003年 | 379篇 |
2002年 | 310篇 |
2001年 | 242篇 |
2000年 | 231篇 |
1999年 | 203篇 |
1998年 | 94篇 |
1997年 | 63篇 |
1996年 | 63篇 |
1995年 | 62篇 |
1994年 | 54篇 |
1993年 | 49篇 |
1992年 | 146篇 |
1991年 | 135篇 |
1990年 | 128篇 |
1989年 | 112篇 |
1988年 | 99篇 |
1987年 | 100篇 |
1986年 | 84篇 |
1985年 | 95篇 |
1984年 | 69篇 |
1983年 | 47篇 |
1982年 | 40篇 |
1981年 | 37篇 |
1980年 | 29篇 |
1979年 | 38篇 |
1978年 | 36篇 |
1977年 | 38篇 |
1976年 | 25篇 |
1975年 | 33篇 |
1974年 | 29篇 |
排序方式: 共有9501条查询结果,搜索用时 78 毫秒
121.
Long-term follow-up for locally advanced and inflammatory breast cancer patients treated with multimodality therapy. 总被引:4,自引:0,他引:4
Jennifer A Low Arlene W Berman Seth M Steinberg David N Danforth Marc E Lippman Sandra M Swain 《Journal of clinical oncology》2004,22(20):4067-4074
PURPOSE: To determine long-term event-free (EFS) and overall survival (OS) for patients with stage III breast cancer treated with combined-modality therapy. PATIENTS AND METHODS: Between 1980 and 1988, 107 patients with stage III breast cancer were prospectively enrolled for study at the National Cancer Institute and stratified by whether or not they had features of inflammatory breast cancer (IBC). Patients were treated to best response with cyclophosphamide, doxorubicin, methotrexate, fluorouracil, leucovorin, and hormonal synchronization with conjugated estrogens and tamoxifen. Patients with pathologic complete response received definitive radiotherapy to the breast and axilla, whereas patients with residual disease underwent mastectomy, lymph node dissection, and radiotherapy. All patients underwent six additional cycles of adjuvant chemotherapy. RESULTS: OS and EFS were obtained with a median live patient follow-up time of 16.8 years. The 46 IBC patients had a median OS of 3.8 years and EFS of 2.3 years, compared with 12.2 and 9.0 years, respectively, in stage IIIA breast cancer patients. Fifteen-year OS survival was 20% for IBC versus 50% for stage IIIA patients and 23% for stage IIIB non-IBC. Pathologic response was not associated with improved survival for stage IIIA or IBC patients. Presence of dermal lymphatic invasion did not change the probability of survival in clinical IBC patients. CONCLUSION: Fifteen-year follow-up of stage IIIA and inflammatory breast cancer is rarely reported; IBC patients have a poor long-term outlook. 相似文献
122.
F-actin fiber distribution in glomerular cells: structural and functional implications 总被引:7,自引:0,他引:7
Cortes P Méndez M Riser BL Guérin CJ Rodríguez-Barbero A Hassett C Yee J 《Kidney international》2000,58(6):2452-2461
BACKGROUND: Glomerular distention is associated with cellular mechanical strain. In addition, glomerular distention/contraction is assumed to influence the filtration rate through changes in filtration surface area. A contractile cytoskeleton in podocytes and mesangial cells, formed by F-actin-containing stress fibers, maintains structural integrity and modulates glomerular expansion. In this study, the glomerular cell distribution of F-actin and vimentin filaments was studied in normal control and nine-month streptozotocin-diabetic rats. Results in situ were compared with observations in tissue culture. METHODS: Microdissected rat glomeruli were perfused to obtain a physiological 25% glomerular expansion over the basal value. Fixation was done without change in glomerular volume. Dual fluorescent labeling of F-actin and vimentin was carried out, and samples were examined by confocal laser scanning microscopy. RESULTS: The podocyte cell bodies and their cytoplasmic projections, including the foot processes, contained bundles of vimentin-containing fibers. Except for a thin layer at the base of foot processes, they did not demonstrate F-actin. While mesangial cells in culture had F-actin as long stress fibers resembling tense cables, mesangial cells stretched in situ contained a maze of short tortuous F-actin fibers organized in bundles that often encircled vascular spaces. This fibrillar organization was disrupted in diabetic glomeruli. CONCLUSION: Mesangial cells, but not podocytes, contain a cytoskeleton capable of contraction that is disorganized in long-term diabetes. Together with previous observations, the distribution of this cytoskeleton suggests that mesangial cell contraction may be involved in the redistribution of glomerular capillary blood flow, but not substantially in the modulation of glomerular distention. Disorganization of stress fibers may be a cause of hyperfiltration in diabetes. 相似文献
123.
124.
125.
Oxidative stress and HNE conjugation of GLUT3 are increased in the hippocampus of diabetic rats subjected to stress 总被引:5,自引:0,他引:5
Reagan LP Magariños AM Yee DK Swzeda LI Van Bueren A McCall AL McEwen BS 《Brain research》2000,862(1-2):292-300
Recent studies demonstrate that cellular, molecular and morphological changes induced by stress in rats are accelerated when there is a pre-existing strain upon their already compromised adaptive responses to internal or external stimuli, such as may occur with uncontrolled diabetes mellitus. The deleterious actions of diabetes and stress may increase oxidative stress in the brain, leading to increases in neuronal vulnerability. In an attempt to determine if stress, diabetes or stress+diabetes increases oxidative stress in the hippocampus, radioimmunocytochemistry was performed using polyclonal antisera that recognize proteins conjugated by the lipid peroxidation product 4-hydroxy-2-nonenal (HNE). Radioimmunocytochemistry revealed that HNE protein conjugation is increased in all subregions of the hippocampus of streptozotocin (STZ) diabetic rats, rats subjected to restraint stress and STZ diabetic rats subjected to stress. Such increases were not significant in the cortex. Because increases in oxidative stress may contribute to stress- and diabetes-mediated decreases in hippocampal neuronal glucose utilization, we examined the stress/diabetes mediated HNE protein conjugation of the neuron specific glucose transporter, GLUT3. GLUT3 immunoprecipitated from hippocampal membranes of diabetic rats subjected to stress exhibited significant increases in HNE immunolabeling compared to control rats, suggesting that HNE protein conjugation of GLUT3 contributes to decreases in neuronal glucose utilization observed during diabetes and exposure to stress. Collectively, these results demonstrate that the hippocampus is vulnerable to increases in oxidative stress produced by diabetes and stress. In addition, increases in HNE protein conjugation of GLUT3 provide a potential mechanism for stress- and diabetes-mediated decreases in hippocampal neuronal glucose utilization. 相似文献
126.
Analgesic effects of botulinum toxin A: a randomized, placebo-controlled clinical trial 总被引:4,自引:0,他引:4
Barwood S Baillieu C Boyd R Brereton K Low J Nattrass G Graham HK 《Developmental medicine and child neurology》2000,42(2):116-121
Postoperative pain in children with spastic cerebral palsy (CP) is often attributed to muscle spasm and is difficult to manage using opiates and benzodiazepines. Adductor-release surgery to treat or prevent hip dislocation in children with spastic CP is frequently performed and is often accompanied by severe postoperative pain and spasm. A double-blinded, randomized, placebo-controlled clinical trial of 16 patients (mean age 4.7 years) with a mainly spastic type of CP (either diplegic or quadriplegic in distribution) was used to test the hypothesis that a significant proportion of postoperative pain is secondary to muscle spasm and, therefore, might be reduced by a preoperative chemodenervation of the target surgical muscle by intramuscular injection of botulinum toxin A (BTX/A). Compared with the placebo, BTX/A was found to be associated with a reduction in mean pain scores of 74% (P<0.003), a reduction in mean analgesic requirements of approximately 50% (P<0.005), and a reduction in mean length of hospital admission of 33% (P<0.003). It was concluded that an important component of postoperative pain in the patient population is due to muscle spasm and this can be managed effectively by preoperative injection with BTX/A. These findings may have implications for the management of pain secondary to muscle spasm in other clinical settings. 相似文献
127.
128.
129.
Kishi Y Nickander KK Schmelzer JD Low PA 《Journal of the peripheral nervous system : JPNS》2000,5(1):11-18
Chronic hyperglycemia results in a large deficit in nerve blood flow. Both autoxidative- and ischemia-induced lipid peroxidation occurs, with resultant peripheral sensory neuropathy in streptozotocin-induced diabetes in the rat. Free radical defenses, especially involving antioxidant enzymes, have been suggested to be reduced, but scant information is available on chronic hyperglycemia. We evaluated the gene expression of glutathione peroxidase, catalase, and superoxide dismutase (cuprozinc and manganese separately) in L4,5 dorsal root ganglion (DRG) and superior cervical ganglion, as well as enzyme activity of glutathione peroxidase in DRG and sciatic nerve in experimental diabetic neuropathy of 3 months and 12 months durations. We also evaluated nerve electrophysiology of caudal, sciatic-tibial, and digital nerves. A nerve conduction deficit was seen in all nerves in experimental diabetic neuropathy at both 3 and 12 months. Gene expression of glutathione peroxidase, catalase, cuprozinc superoxide dismutase, and manganese superoxide dismutase were not reduced in experimental diabetic neuropathy at either 3 or 12 months. Catalase mRNA was significantly increased in experimental diabetic neuropathy at 12 months. Glutathione peroxidase enzyme activity was normal in sciatic nerve. We conclude that gene expression is not reduced in peripheral nerve tissues in very chronic experimental diabetic neuropathy. Changes in enzyme activity may be related to duration of diabetes or due to post-translational modifications. 相似文献
130.
Kathryn H Schmitz Rehana L Ahmed Peter J Hannan Douglas Yee 《Cancer epidemiology, biomarkers & prevention》2005,14(7):1672-1680
BACKGROUND: This randomized controlled trial assessed the safety and effects of twice-weekly weight training among recent breast cancer survivors. Outcomes included body size and biomarkers hypothesized to link exercise and breast cancer risk. METHODS: A convenience sample of 85 recent survivors was randomized into immediate and delayed treatment groups. The immediate group trained from months 0 to 12; the delayed treatment group served as a no exercise parallel comparison group from months 0 to 6 and trained from months 7 to 12. Measures at baseline, 6 and 12 months included body weight, height, body fat, lean mass, body fat %, and waist circumference, as well as fasting glucose, insulin, insulin resistance, insulin-like growth factor-I (IGF-I), IGF-II, and IGF-binding protein-1, IGFBP-2, and IGFBP-3. Injury reporting was standardized. RESULTS: The intervention resulted in significant increases in lean mass (0.88 versus 0.02 kg, P < 0.01), as well as significant decreases in body fat % (-1.15% versus 0.23%, P = 0.03) and IGF-II (-6.23 versus 28.28 ng/mL, P = 0.02) comparing immediate with delayed treatment from baseline to 6 months. Within-person changes experienced by delayed treatment group participants during training versus no training were similar. Only one participant experienced a study related injury that prevented continued participation. CONCLUSION: Twice-weekly weight training is a safe exercise program for recent breast cancer survivors that may result in increased muscle mass, as well as decreased body fat % and IGF-II. The implications of these results on cancer recurrence or survival may become more evident with longer exercise intervention trials among breast cancer survivors. 相似文献