全文获取类型
收费全文 | 10511篇 |
免费 | 1106篇 |
国内免费 | 70篇 |
专业分类
耳鼻咽喉 | 90篇 |
儿科学 | 327篇 |
妇产科学 | 276篇 |
基础医学 | 1314篇 |
口腔科学 | 204篇 |
临床医学 | 1130篇 |
内科学 | 2324篇 |
皮肤病学 | 106篇 |
神经病学 | 767篇 |
特种医学 | 642篇 |
外国民族医学 | 1篇 |
外科学 | 1181篇 |
综合类 | 293篇 |
一般理论 | 2篇 |
预防医学 | 1328篇 |
眼科学 | 311篇 |
药学 | 817篇 |
中国医学 | 9篇 |
肿瘤学 | 565篇 |
出版年
2021年 | 147篇 |
2019年 | 145篇 |
2018年 | 166篇 |
2017年 | 104篇 |
2016年 | 136篇 |
2015年 | 148篇 |
2014年 | 200篇 |
2013年 | 365篇 |
2012年 | 450篇 |
2011年 | 487篇 |
2010年 | 301篇 |
2009年 | 274篇 |
2008年 | 398篇 |
2007年 | 516篇 |
2006年 | 416篇 |
2005年 | 429篇 |
2004年 | 447篇 |
2003年 | 412篇 |
2002年 | 397篇 |
2001年 | 328篇 |
2000年 | 337篇 |
1999年 | 294篇 |
1998年 | 150篇 |
1997年 | 130篇 |
1996年 | 127篇 |
1995年 | 124篇 |
1994年 | 128篇 |
1993年 | 98篇 |
1992年 | 223篇 |
1991年 | 225篇 |
1990年 | 210篇 |
1989年 | 211篇 |
1988年 | 176篇 |
1987年 | 194篇 |
1986年 | 159篇 |
1985年 | 176篇 |
1984年 | 143篇 |
1983年 | 142篇 |
1982年 | 116篇 |
1981年 | 124篇 |
1980年 | 93篇 |
1979年 | 123篇 |
1978年 | 103篇 |
1977年 | 91篇 |
1976年 | 116篇 |
1975年 | 115篇 |
1974年 | 142篇 |
1973年 | 121篇 |
1972年 | 111篇 |
1971年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Graham C Scanlon Mark S Wallace J Sorin Ispirescu Gery Schulteis 《Journal of investigative medicine》2006,54(5):238-244
BACKGROUND: Intradermal capsaicin is a human pain model that produces reliable pain and sensitization. This model facilitates controlled testing of analgesic efficacy via a crossover design while minimizing confounding variables in clinical pain states and retaining sufficient power with small samples. METHODS: To determine the lowest dose of capsaicin that produces consistent neurosensory measures, we administered 0.1, 1, 10, or 100 microg to healthy volunteers in a blinded manner (N = 19). Pain scores were recorded at 0, 5, 10, 15, and 60 minutes on a visual analog scale from 0 to 100. Areas and intensities of mechanical allodynia (foam brush stimulus) and pinprick hyperalgesia (von Frey test) were quantified at 15 and 60 minutes, as were flare areas. RESULTS: Capsaicin produced dose-dependent increases in spontaneous pain (p = .013), the area and intensity of mechanical allodynia (p = .006 and p < .001, respectively), the area and intensity of pinprick hyperalgesia (p = .010 and p = .014, respectively), and the flare area (p = .010). The 10 microg dose produced greater spontaneous pain than the 1 microg dose (p = .017). The 100 microg dose produced greater spontaneous pain than the 10 microg, but the difference was not statistically significant. CONCLUSION: The 10 and 100 microg capsaicin doses produced robust pain measures across a range of modalities, and lower doses produced minimal effects. Whereas most studies use 100 microg, using a lower dose is reasonable and may facilitate detection of subtle analgesic effects--particularly with nonopioid analgesics--and drugs can be tested in lower doses, minimizing adverse side effects. 相似文献
53.
Margret S. Magid Wallace G. Campbell Jr MD Sutini Ngadiman Thomas A. Godwin MD Robert Ward 《Fetal and pediatric pathology》1997,17(2):303-314
We report a case of an infantile myofibromatosis with hemangiopericytoma-like features arising in the tongue of a 5-month-old female infant. Many authors now classify neoplasms as infantile myofibromatosis that were previously called infantile hemangiopericytoma. The ultrastructural features of our tumor illustrate its biphasic nature and provide a possible explanation for its histogenesis. Infantile myofibromatosis, including those diagnosed as infantile hemangiopericytomas, rarely arise in any intraoral location. Despite the generally good prognosis associated with these neoplasms, complete surgical excision is recommended to avoid recurrences. 相似文献
54.
55.
Chad Galer Anthony Yonkers Wallace Duff Barbara Heywood 《Otolaryngology--head and neck surgery》2007,136(2):241-245
OBJECTIVE: To examine the clinical significance of acoustic data recorded by the SNAP home polysomnography system (SNAP Laboratories, Glenview, IL). STUDY DESIGN AND SETTING: Retrospective analysis of SNAP data from 59 patients undergoing evaluation for sleep apnea at the University of Nebraska Medical Center and an associated private practice in Omaha, NE. RESULTS: Snoring did not correlate with anthropometric variables such as body mass index and neck circumference. Statistical analysis showed no correlation between respiratory disturbance index and the maximum or average loudness of snoring. Average loudness was predictive of the presence of sleep apnea. Spectral analysis of snoring sonography found that the proportion of snoring events associated with a palatal source correlated strongly with the loudness of snoring. CONCLUSION: These data suggest that analysis of snoring has limited utility in the evaluation of the patient with sleep apnea but may be able to select patients who would benefit from palatal procedures to reduce snoring. 相似文献
56.
57.
William E. Robinson David K. Ryan Gordon T. Wallace 《Archives of environmental contamination and toxicology》1993,25(4):415-421
Ingested matter can have a significant effect on whole body metal concentration measurements in Mytilus edulis. Depuration of mussels in clean seawater for 36 h prior to dissection eliminates most of these contaminating gut contents. Depuration followed by metal analyses is the most direct method of determining mussel tissue metal bioburdens. After being transplanted into a plume of primary treated sewage effluent in Salem Harbor, Massachusetts for 32 days, Al, Cr, and Fe concentrations in depurated mussels were significantly lower than those determined for either non-depurated mussels or for depurated mussels to which fecal concentrations of Al, Cr, and Fe were added back in. Although mathematical methods developed by both Ouellette (1978) and Boehm et al. (1988) could be applied to non-depurated mussels in order to correct for errors associated with gut metal contamination, these indirect methods were not as reliable as depuration prior to analysis. 相似文献
58.
Abstract Current research has provided evidence that nearly 90 percent of all cancers may be related to diet, environment, and lifestyle. Of this number, 30 to 40 percent of cancers in men and up to 60 percent of cancers in women may be related to diet and nutrition. The two-stage process in the formation of many cancers, defined as initiation and promotion, is influenced by many dietary components. Vitamins C, E, and the mineral selenium are nutrients that function as antioxidants, reducing potential cancer-causing chemicals in the body. These natural anticarcinogens are thought to alter the cancer process and are currently under study for their cancer prevention properties. The functions, Recommended Dietary Allowances, food sources, research evidence for cancer prevention, and recommendations for supplementation are presented for these three nutrients. Research suggests that the proper and prudent use of nutrients, along with a healthy diet and lifestyle, may offer protection against this devastating disease. 相似文献
59.
Exacerbation of experimental colitis by nonsteroidal anti-inflammatory drugs is not related to elevated leukotriene B4 synthesis. 总被引:6,自引:0,他引:6
The ability of nonsteroidal anti-inflammatory drugs to exacerbate experimental colitis, and the possible contributions of the "shunting" of arachidonate via the 5-lipoxygenase pathway, were investigated using a rat model in which colitis was induced by intracolonic administration of trinitrobenzene sulfonic acid in a vehicle of 50% ethanol. Twice daily treatment with indomethacin (0.1-1 mg/kg SC) during the first week after trinitrobenzene sulfonic acid/ethanol administration resulted in dose-dependent increases in the severity of colitis and in the incidence of mortality. Mortality was not observed in vehicle-treated colitic rats or in normal rats treated with indomethacin. Similar exacerbation of colitis was observed in rats treated with naproxen (5 mg/kg). Whereas treatment with a 5-lipoxygenase inhibitor, PF-5901 (100 mg/kg PO), resulted in a significant reduction of the severity of colitis, concomitant administration of PF-5901 and indomethacin (0.5 mg/kg SC) did not inhibit the exacerbative effects of the indomethacin in this model. In separate studies, administration of indomethacin was found to significantly increase colonic myeloperoxidase activity (a measure of tissue granulocyte numbers) and suppress colonic prostaglandin E2 synthesis, while not significantly affecting colonic leukotriene B4 synthesis. The effect on myeloperoxidase activity was seen during the period 21-24 hours after trinitrobenzene sulfonic acid ethanol administration, but not during the period 45-48 hours after induction of colitis. In in vitro studies using samples of inflamed colon and in vivo studies in which colonic eicosanoid production was measured by colonic dialysis, inhibition of prostaglandin E2 synthesis was not accompanied by significant changes in leukotriene B4 synthesis. These results suggest that inhibitors of colonic prostaglandin synthesis can markedly exacerbate colitis, and that this effect is unrelated to alterations in colonic leukotriene B4 synthesis. Endogenous prostaglandins may exert anti-inflammatory effects during the acute stages of colitis. 相似文献
60.
Oligoclonal immunoglobulins in HIV infection 总被引:1,自引:0,他引:1
We tested 150 patients infected with human immunodeficiency virus (HIV) for the presence of oligoclonal bands in serum, prompted by reports that these abnormal proteins may have prognostic significance. Sixty HIV-negative individuals from "at-risk" groups were tested along with 80 HIV-negative, healthy blood donors for the presence of these bands. All sera were tested by isoelectric focusing, because it is more sensitive for this purpose than more-conventional electrophoretic techniques. In the HIV-positive group, 61% of the sera had oligoclonal bands; in the HIV-negative "at-risk" group, 36% had bands. No bands were detectable in sera from the healthy blood-donor group. Some patients were also followed for differing periods throughout their infection, and changes in their oligoclonal banding patterns could not be correlated with disease progression. The fact that oligoclonal bands were found to be present without HIV infection in a substantial number of individuals from within the "at-risk" groups leads us to conclude that the presence of oligoclonal bands in HIV infection is of limited prognostic significance. 相似文献