全文获取类型
收费全文 | 2951309篇 |
免费 | 230136篇 |
国内免费 | 5909篇 |
专业分类
耳鼻咽喉 | 42635篇 |
儿科学 | 91639篇 |
妇产科学 | 80895篇 |
基础医学 | 414840篇 |
口腔科学 | 84080篇 |
临床医学 | 265153篇 |
内科学 | 578514篇 |
皮肤病学 | 60497篇 |
神经病学 | 246239篇 |
特种医学 | 117936篇 |
外国民族医学 | 1130篇 |
外科学 | 449869篇 |
综合类 | 68602篇 |
现状与发展 | 1篇 |
一般理论 | 1199篇 |
预防医学 | 234998篇 |
眼科学 | 69357篇 |
药学 | 219099篇 |
4篇 | |
中国医学 | 5553篇 |
肿瘤学 | 155114篇 |
出版年
2018年 | 30275篇 |
2017年 | 23516篇 |
2016年 | 25804篇 |
2015年 | 29079篇 |
2014年 | 41891篇 |
2013年 | 63948篇 |
2012年 | 86134篇 |
2011年 | 90944篇 |
2010年 | 53876篇 |
2009年 | 51691篇 |
2008年 | 86483篇 |
2007年 | 91832篇 |
2006年 | 92677篇 |
2005年 | 90429篇 |
2004年 | 86915篇 |
2003年 | 84021篇 |
2002年 | 82823篇 |
2001年 | 135278篇 |
2000年 | 139625篇 |
1999年 | 118294篇 |
1998年 | 34150篇 |
1997年 | 31097篇 |
1996年 | 30875篇 |
1995年 | 29640篇 |
1994年 | 27844篇 |
1993年 | 26057篇 |
1992年 | 94867篇 |
1991年 | 91529篇 |
1990年 | 88559篇 |
1989年 | 85367篇 |
1988年 | 79375篇 |
1987年 | 78135篇 |
1986年 | 74349篇 |
1985年 | 70871篇 |
1984年 | 53600篇 |
1983年 | 45730篇 |
1982年 | 27946篇 |
1981年 | 24732篇 |
1979年 | 50267篇 |
1978年 | 35257篇 |
1977年 | 29867篇 |
1976年 | 28035篇 |
1975年 | 29791篇 |
1974年 | 36479篇 |
1973年 | 34697篇 |
1972年 | 32614篇 |
1971年 | 30134篇 |
1970年 | 28514篇 |
1969年 | 26613篇 |
1968年 | 24534篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A survey of hospitals in New York State treating psychiatric patients with chemical abuse disorders.
Eighty-eight of 143 hospitals in New York State providing psychiatric inpatient treatment responded to a mailed questionnaire designed to determine the size of three subgroups of chemical abusers--alcohol abusers, drug abusers, and polychemical abusers--among inpatients with psychiatric diagnoses, as well as the availability of services for these patients. Data for New York City and its metropolitan area were analyzed separately. In 1987 almost one-third of psychiatric admissions both in and outside the metropolitan area had comorbid chemical abuse disorders. Seventy-five percent of patients in the metropolitan area with comorbid chemical abuse had a drug abuse disorder; in rural areas 88 percent of patients with chemical abuse disorders abused alcohol. Both hospital- and community-based aftercare services, especially in the metropolitan area, were less available to psychiatric patients with chemical abuse than to patients without these disorders. 相似文献
992.
Two experiments examined the ingestive responses of streptozotocin-diabetic rats fed low-fat or high-fat diets to glucose, fructose, sucrose and maltose solutions in brief (30 min) intake tests. In Experiment 1, one-bottle acceptability tests were used whereas two-bottle preference tests were used in Experiment 2. Three main findings resulted from these studies. Firstly, diabetic rats fed the low-fat diet displayed a reduced acceptance of and preference for all concentrated sugar solutions. Secondly, glucose consumption patterns of diabetic rats fed the low-fat diet were distinctly different from their responses to the other sugars. Thirdly feeding high-fat diets, either high or low in carbohydrate, normalized the responses of diabetic rats to the sugar solutions. The results suggest that feeding high-fat diets to diabetic rats normalizes their responses to sugar solutions because of reductions in hunger and thirst associated with the provision of a utilizable source of calories and an improvement in body fluid balance. 相似文献
993.
V L Towle J C Witt S H Nader A T Reder R Foust J P Spire 《Electroencephalography and clinical neurophysiology》1991,80(5):339-346
Pattern visual evoked potentials were obtained from 46 patients with definite relapsing/remitting multiple sclerosis, using both a conventional 5-channel occipital array and a 3-D recording technique consisting of three bipolar derivations approximating the three dimensions of space. These three orthogonal wave forms were displayed as a 3-D Lissajous trajectory for each subject. Two of the 15 patients with completely normal conventional pattern VEPs had abnormalities of the orientation of the B-C curvilinear segment of the 3-D pattern VEPs. Delays in the first major occipital positive component (P100) were evident using both techniques; the correlation between P100 latency and the latency of the corresponding trajectory apex was r = 0.99 (P less than 0.01). Post-chiasmal MRI abnormalities were associated with 3-D VEP orientation abnormalities. Three-dimensional pattern VEPs are moderately more sensitive than conventional pattern VEPs at detecting dysfunction posterior to the optic chiasm in demyelinating disease and do not require the use of eccentric fixation to do so. 相似文献
994.
F Leca D Marchiset-Leca A Noble M Antonetti 《European journal of drug metabolism and pharmacokinetics》1991,16(2):107-111
Twenty-two days after administration by intravenous bolus, of 50 mg of adriamycin to several patients we found concentrations of adriamycin and adriamycinol of the order of 100 pcg/ml. In theory, however, with a terminal half-life of 30 h, the plasma levels of adriamycin and adriamycinol should be close to 0.1 pcg/ml. Further pharmacokinetic investigation was therefore necessary. We have retained for this study nine male patients, aged between 53 and 69 years who received 25 to 50 mg of adriamycin by slow intravenous injection. The HPLC method permitted the detection of 50 pcg/ml of adriamycin and adriamycinol, with the possibility of monitoring their elimination during 120 h (and in one case during 160 h). The terminal half-lives of elimination estimated in 8 patients were respectively 110 +/- 52 h for adriamycin and 92 h 50 min +/- 43 h for adriamycinol. Surface ratios under adriamycinol curves against calculated adriamycin was 1.10 +/- 0.26. Plasma levels found during the To in certain patients correspond to the end of the drug elimination of the previous treatment. It is difficult with a half-life to 110 h to predict the effects of residual concentrations of adriamycin and adriamycinol. 相似文献
995.
996.
Following an encephalopathic illness, a 13-year-old Chinese boy had a partial form of Klüver-Bucy syndrome with emotional disturbance, recent memory loss, hypersexuality, and polyphagia. Other unusual features included narcolepsy, polydipsia, and polyuria. Virologic studies failed to incriminate the etiologic agent, including herpes simplex virus. Brain biopsy of the frontal lobe demonstrated Alzheimer type II astrocytosis. 相似文献
997.
B T Hyman J E Flory S E Arnold G W Van Hoesen R L Schelper H Ghanbari H Haigler 《Journal of geriatric psychiatry and neurology》1991,4(4):231-235
A quantitative assay for ALZ-50 immunoreactivity was evaluated in samples of superior temporal gyrus taken at autopsy from 13 Alzheimer patients and 11 controls. The assayable immunoreactivity appears to be stable for at least 24 hours postmortem but was lost with formalin fixation. The mean value of the Alzheimer patients was tenfold higher than that of the controls (P less than .002). The values of four Alzheimer samples overlapped with the low levels seen in controls, but no controls had elevated levels. In this sample population, therefore, the assay had a sensitivity of 69% and specificity of 100%. 相似文献
998.
HEAD CIRCUMFERENCE AND INTELLECTUAL PERFORMANCE OF PATIENTS WITH DUCHENNE MUSCULAR DYSTROPHY 总被引:3,自引:1,他引:2
R. E. Appleton K. Bushby D. Gardner-Medwin J. Welch P. J. Kelly 《Developmental medicine and child neurology》1991,33(10):884-890
The head circumferences of 64 patients with Duchenne muscular dystrophy were measured and found to be greater than those of a normal population. The patients had relative, and in 12 cases, absolute macrocephaly. 47 of the 64 patients underwent intelligence testing and were found to be significantly intellectually impaired, particularly in verbal and language skills. There was no correlation between head circumference or absolute macrocephaly and intellectual performance. The cause of macrocephaly in these patients is unknown and its relevance to the aetiology of intellectual impairment in Duchenne muscular dystrophy is not yet clear. 相似文献
999.
Central axons of sensory ganglion (SG) neurons of the Xenopus tail enter the spinal cord via the ventral roots and travel dorsally and rostrally following a diagonal course within the lateral marginal zone (LMZ) to reach the dorsolateral fasciculus (DLF) (Nordlander et al.: Brain Res., 440:391-395, 1988). Axons are dispersed as they cross the cord. At the DLF they turn and travel together rostrally, sharing the fascicle with axons of primary sensory neurons (Rohon-Beard cells) already present in the tract. In this paper we analyze the growth patterns of the central projections of SG axons in the tail by using HRP applied to proximal branches of tail spinal nerves. Growth cones of the diagonal route are variable in configuration, often bearing processes that spread within the LMZ. Once the DLF, growth cones change shape, becoming distinctly linear. While growth cones navigating the diagonal part of the route never contact or fasciculate with other diagonal SG axons, SG growth cones and axons of the DLF are more closely associated with their fellows. Measurements of the slopes of SG axons in the diagonal route indicated a limited range with a mean of 23 degrees with respect to the cord axis. On the basis of these observations, we conclude that 1) navigational patterns for growth cones of this pathway differ for the diagonal versus the DLF part of its course, and 2) fasciculation is not a mechanism used by SG axons to reach the DLF, but that instead, each axon is able to find its way independently. 相似文献
1000.