全文获取类型
收费全文 | 56656篇 |
免费 | 4476篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 608篇 |
儿科学 | 2086篇 |
妇产科学 | 1260篇 |
基础医学 | 7256篇 |
口腔科学 | 809篇 |
临床医学 | 8359篇 |
内科学 | 10113篇 |
皮肤病学 | 854篇 |
神经病学 | 5417篇 |
特种医学 | 1369篇 |
外国民族医学 | 12篇 |
外科学 | 5532篇 |
综合类 | 664篇 |
一般理论 | 74篇 |
预防医学 | 7468篇 |
眼科学 | 1136篇 |
药学 | 3841篇 |
中国医学 | 55篇 |
肿瘤学 | 4336篇 |
出版年
2023年 | 379篇 |
2022年 | 550篇 |
2021年 | 1102篇 |
2020年 | 749篇 |
2019年 | 1246篇 |
2018年 | 1385篇 |
2017年 | 1022篇 |
2016年 | 1097篇 |
2015年 | 1245篇 |
2014年 | 1735篇 |
2013年 | 2676篇 |
2012年 | 3835篇 |
2011年 | 4073篇 |
2010年 | 2171篇 |
2009年 | 1971篇 |
2008年 | 3478篇 |
2007年 | 3491篇 |
2006年 | 3441篇 |
2005年 | 3396篇 |
2004年 | 3207篇 |
2003年 | 2853篇 |
2002年 | 2737篇 |
2001年 | 861篇 |
2000年 | 869篇 |
1999年 | 791篇 |
1998年 | 635篇 |
1997年 | 523篇 |
1996年 | 432篇 |
1995年 | 392篇 |
1994年 | 369篇 |
1993年 | 362篇 |
1992年 | 551篇 |
1991年 | 537篇 |
1990年 | 502篇 |
1989年 | 511篇 |
1988年 | 448篇 |
1987年 | 489篇 |
1986年 | 418篇 |
1985年 | 434篇 |
1984年 | 382篇 |
1983年 | 339篇 |
1982年 | 242篇 |
1981年 | 253篇 |
1980年 | 222篇 |
1979年 | 320篇 |
1978年 | 249篇 |
1977年 | 192篇 |
1975年 | 186篇 |
1974年 | 198篇 |
1972年 | 185篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
An investigation has been made into the effect of 3,4-methylenedioxymethamphetamine (MDMA or ‘Ecstasy’) administration on the concentration of 5-hydroxytryptamine (5-HT), uptake of [3H]5-HT and [3H]paroxetine binding in rat cerebral cortex tissue. Four days after 2 injections of MDMA (20 mg/kg i.p., 6 hr apart) the concentrations of 5-HT and its metabolite 5-HIAA were reduced by 60%. The binding of [3H]paroxetine to the presynaptic 5-HT transporter was decreased and high affinity uptake of [3H]5-HT was reduced by a similar amount, indicating neurodegeneration of 5-HT terminals. Pretreatment with chlormethiazole (100 mg/kg i.p.), 10 min before each MDMA injection prevented the decrease in both [3H]parotextine binding and uptake of [3H]5-HT. The loss in 5-HT and 5-HIAA content was also attenuated. Pretreatment with dizocilpine (1 mg/kg i.p.) or haloperidol (2 mg/kg i.p.) also prevented the MDMA-induced loss of [3H]paroxetine binding and attenuated the loss of 5-HT and 5-HIAA content. All three compounds also decreased the degree of hyperthermia that follows MDMA administration, although previous studies suggest that the long term neurodegeneration is not associated with the acute hyperthermic response. These data support the findings of others that MDMA injection produces degeneration of 5-HT nerve terminals in the cortex, confirm that chlormethiazole, dizocilpine and haloperidol attenuate MDMA-induced neurotoxic loss of 5-HT and demonstrate for the first time that these compounds prevent the neurodegeneration of 5-HT nerve terminals that follows MDMA administration. 相似文献
92.
Peter M. Ravdin Stephanie Green James H. Doroshow Silvana Martino 《Investigational new drugs》1994,12(4):333-336
Summary Thirty-two eligible patients with advanced metastatic breast cancer who had received no more than 1 prior chemotherapy regimen for metastatic disease (16 had received prior doxorubicin) were treated with piroxantrone at a dose of 120 mg/m2 intravenously every 21 days. In the twenty-seven patients evaluable for response, two partial responses were seen. Toxicities observed were primarily hematologic with grade 3 or greater granulocytopenia occurring in 34% of the patients. One patient developed symptomatic congestive heart failure at a total cumulative dose of 960 mg/m2. We conclude that piroxantrone given at this dose and schedule has minimal activity in patients with metastatic breast cancer. 相似文献
93.
94.
Topical dexamethasone was used to elevate rabbit intraocular pressure in order to study the interaction with a steroid antagonist, mifepristone. Dexamethasone did not cause a consistently significant increase in intraocular pressure. Animals treated with mifepristone followed by dexamethasone showed no apparent increase in intraocular pressure after dexamethasone, indeed mifepristone caused a lower intraocular pressure than seen in other groups whether in the presence or absence of dexamethasone. Reductions of intraocular pressure when mifepristone was given after 14 days of dexamethasone administration were not found. No conclusion can be reached regarding any dexamethasone antagonism by mifepristone, except that intraocular pressure tended to be lower even in the presence of dexamethasone. 相似文献
95.
D K Williams D R Carlton S H Green K Pearman T R Cole 《Journal of medical genetics》1997,34(10):842-845
We report a child of 3 years 9 months with the Marshall-Smith syndrome (MSS), characterised by the typical facial features, developmental delay, and advanced bone age. After the diagnosis was made at 5 months of age, careful observation for respiratory complications and failure to thrive was initiated. By 3 1/2 years of age, although our patient had no life threatening respiratory complications, investigation showed significant upper airway obstruction, which has been successfully treated. Aggressive treatment for failure to thrive has also allowed her to maintain a weight on the 50th centile. The purpose of this report is to suggest that early diagnosis and aggressive management may improve the ultimate prognosis with respect to the respiratory and feeding difficulties seen in this rare syndrome. 相似文献
96.
97.
Body pain and treatment response in late-life depression. 总被引:2,自引:0,他引:2
Jordan F Karp Debra Weiner Karen Seligman Meryl Butters Mark Miller Ellen Frank Jacqueline Stack Benoit H Mulsant Bruce Pollock Mary Amanda Dew David J Kupfer Charles F Reynolds 《The American journal of geriatric psychiatry》2005,13(3):188-194
OBJECTIVE: The authors investigated the influence of body pain on 1) time to treatment response and 2) suicidal ideation, in late-life depression. They hypothesized that higher levels of body pain would predict a longer time to and lower likelihood of response, and increased levels of suicidal ideation. METHODS: Subjects (N=187) were older adult outpatients (age > or =69 years), with current episodes of major depression, who were openly treated with paroxetine up to 40 mg daily and weekly interpersonal psychotherapy. Response was defined as 3 consecutive weeks of Hamilton Rating Scale for Depression at < or =10. Body pain was measured with the Bodily Pain Index of the SF-36 quality-of-life assessment. Authors used survival-analysis models on the responder sample to test the effect of body pain on response, after controlling for severity of depression. RESULTS: Overall response rate was 75.4%. Nonresponders reported more severe pain at baseline. After covarying for severity of baseline depression, no effect was found for physical pain on time-to-response or degree of suicidality. Bodily pain remained stable during acute treatment for responders, independent of depression response to combination psychotherapy and antidepressant treatment. CONCLUSIONS: Older adult patients with higher levels of physical pain can still respond to antidepressant treatment; however, reported bodily pain may be associated with a more difficult-to-treat depression. 相似文献
98.
99.
100.
Amir Kimia MD John S. Brownstein PhD Karen L. Olson PhD Victor Zak PhD Florence T. Bourgeois MD MPH Kenneth D. Mandl MD MPH 《Academic emergency medicine》2006,13(7):767-773
Background: The Centers for Disease Control and Prevention is incorporating laboratory data into real-time surveillance systems. When normal patterns of laboratory test orders and results are modeled, aberrations can be detected. Because many test orders are available electronically well before results, atypical patterns of test ordering may signal outbreaks.
Objectives: The authors sought to characterize baseline patterns in the ordering and early results of lumbar punctures, motivated by the possibility of using these data for real-time surveillance for early detection of meningitis or encephalitis outbreaks.
Methods: Retrospective cohorts of pediatric emergency department patients at a single hospital (1993–2003) and from the National Hospital and Ambulatory Medical Care Survey (1992–2000) were used for analysis.
Results: Test ordering exhibits seasonal patterns, with monthly peaks in January and August (p < 0.0001). For the hospital cohort, the rate of cerebrospinal fluid pleocytosis exhibits seasonal patterns (p < 0.0001), with a peak from August to October. This is strongly associated with the rate and pattern of clinical neurologic disease (p < 0.0001). A long-term secular decline in daily test ordering is evident, dropping from 5.3 to 2.9 in the hospital sample, and from 371.8 to 185.3 in the national sample (p < 0.001). The long-term rate of pleocytosis has declined (p < 0.0001), though the yield of testing for pleocytosis has improved (p = 0.0104).
Conclusions: Laboratory test patterns correspond with those of clinical disease and are a promising source of surveillance data. Using such data for real-time monitoring requires specific adjustments for patient age, periodicities, and secular trends. 相似文献
Objectives: The authors sought to characterize baseline patterns in the ordering and early results of lumbar punctures, motivated by the possibility of using these data for real-time surveillance for early detection of meningitis or encephalitis outbreaks.
Methods: Retrospective cohorts of pediatric emergency department patients at a single hospital (1993–2003) and from the National Hospital and Ambulatory Medical Care Survey (1992–2000) were used for analysis.
Results: Test ordering exhibits seasonal patterns, with monthly peaks in January and August (p < 0.0001). For the hospital cohort, the rate of cerebrospinal fluid pleocytosis exhibits seasonal patterns (p < 0.0001), with a peak from August to October. This is strongly associated with the rate and pattern of clinical neurologic disease (p < 0.0001). A long-term secular decline in daily test ordering is evident, dropping from 5.3 to 2.9 in the hospital sample, and from 371.8 to 185.3 in the national sample (p < 0.001). The long-term rate of pleocytosis has declined (p < 0.0001), though the yield of testing for pleocytosis has improved (p = 0.0104).
Conclusions: Laboratory test patterns correspond with those of clinical disease and are a promising source of surveillance data. Using such data for real-time monitoring requires specific adjustments for patient age, periodicities, and secular trends. 相似文献