全文获取类型
收费全文 | 28263篇 |
免费 | 2348篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 346篇 |
儿科学 | 1010篇 |
妇产科学 | 672篇 |
基础医学 | 3415篇 |
口腔科学 | 563篇 |
临床医学 | 3641篇 |
内科学 | 5199篇 |
皮肤病学 | 430篇 |
神经病学 | 2769篇 |
特种医学 | 998篇 |
外科学 | 3574篇 |
综合类 | 647篇 |
一般理论 | 46篇 |
预防医学 | 3155篇 |
眼科学 | 502篇 |
药学 | 2117篇 |
2篇 | |
中国医学 | 33篇 |
肿瘤学 | 1520篇 |
出版年
2021年 | 396篇 |
2020年 | 233篇 |
2019年 | 346篇 |
2018年 | 415篇 |
2017年 | 297篇 |
2016年 | 357篇 |
2015年 | 403篇 |
2014年 | 611篇 |
2013年 | 921篇 |
2012年 | 1169篇 |
2011年 | 1321篇 |
2010年 | 741篇 |
2009年 | 544篇 |
2008年 | 1155篇 |
2007年 | 1272篇 |
2006年 | 1263篇 |
2005年 | 1186篇 |
2004年 | 1180篇 |
2003年 | 1022篇 |
2002年 | 964篇 |
2001年 | 961篇 |
2000年 | 974篇 |
1999年 | 770篇 |
1998年 | 277篇 |
1997年 | 263篇 |
1996年 | 226篇 |
1995年 | 232篇 |
1992年 | 685篇 |
1991年 | 703篇 |
1990年 | 654篇 |
1989年 | 600篇 |
1988年 | 592篇 |
1987年 | 549篇 |
1986年 | 558篇 |
1985年 | 538篇 |
1984年 | 423篇 |
1983年 | 416篇 |
1982年 | 267篇 |
1981年 | 250篇 |
1980年 | 226篇 |
1979年 | 423篇 |
1978年 | 308篇 |
1977年 | 265篇 |
1976年 | 239篇 |
1975年 | 229篇 |
1974年 | 299篇 |
1973年 | 261篇 |
1972年 | 233篇 |
1971年 | 226篇 |
1970年 | 207篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
81.
82.
The rates of incorporation of [3H]choline and [3H]ethanolamine into membrane phospholipids of platelets from 22 drug-free Alzheimer's disease patients and 18 normal elderly controls were compared. No significant differences between groups were found. If alterations in lipid metabolism are involved in the pathophysiological processes underlying Alzheimer's disease, such alterations are not manifest in measures of radiolabeled base incorporation into platelet phospholipids. 相似文献
83.
84.
Acute myelocytic leukemia and prior allergies 总被引:1,自引:0,他引:1
R K Severson S Davis D B Thomas R G Stevens L Heuser L E Sever 《Journal of clinical epidemiology》1989,42(10):995-1001
The relationship between prior allergies and adult acute myelocytic leukemia was investigated in a population-based case-control study. Based on data from personal interviews of 98 cases and 133 controls, a history of any type of allergy was associated with a significantly decreased risk of acute myelocytic leukemia (OR = 0.35, 95% CI = 0.20-0.60). Risk declined with the total number of specific allergies reported (p less than 0.001), and was reduced in relation to a history of prior asthma, eczema and hives. The implications of these findings in relation to natural immune surveillance against developing neoplasms are discussed. 相似文献
85.
D L Goad C M Davis P Liem C C Fuselier J R McCormack K M Olsen 《The Journal of clinical psychiatry》1991,52(8):342-345
BACKGROUND: Currently there is no regimen for managing the inappropriate behavior seen in Alzheimer's disease that does not cause significant patient sedation. Preliminary evidence suggests selegiline may be effective in behavioral modification without the adverse effects observed with other regimens. The purpose of this study was to document the efficacy of selegiline in Alzheimer's patients with behavior problems. METHOD: Eight Alzheimer's patients (6 women and 2 men) ranging in age from 50 to 82 years (mean +/- SD = 74.0 +/- 10.5) were enrolled in this single-blind study. Patients received selegiline 10 mg each day for 8 weeks. Prior to drug administration and at the end of Weeks 1, 2, 4, 6, and 8, patients were evaluated for behavior (BEHAVEAD), cognitive function (Mini-Mental State Examination), and caregiver stress (Caregiver Burden Scale). RESULTS: Of eight enrolled patients, five were available for analysis. No statistically significant differences were found between mean baseline and mean 8-week scores for any of the three tests. However, clinical significance was noted by improvement in cognition (orientation and recall), caregiver stress, and behavior. Behavior was noted to improve in the areas of paranoid and delusional ideation, hallucinations, activity disturbances, anxiety, and phobias. CONCLUSION: These data suggest that some Alzheimer's patients with behavior problems may benefit from selegiline therapy. 相似文献
86.
After years of decline to near disappearance, there recently has been an increasing incidence of syphilis in America. New cases of tertiary neurosyphilis are being reported which often have associated significant urologic sequelae. For the first time in the English literature, the uro-dynamic findings of a patient with tabes dorsalis are presented. Our findings indicate that treatment of urinary retention associated with tabes dorsalis is better managed by intermittent catheterization than by prostate surgery because of the impaired detrusor activity. A review of neurosyphilis and its urologic implications and urodynamic findings are presented. Prompt recognition of this entity should encourage a full urodynamic evaluation prior to a commitment to prostatic surgery. 相似文献
87.
Renal transplantation from elderly living donors 总被引:1,自引:0,他引:1
N Sumrani V Delaney Z K Ding R Davis P Daskalakis A Tejani K Butt J Hong 《Transplantation》1991,51(2):305-309
A worldwide shortage of cadaveric donors has led to the increased utilization of elderly living donors, with controversial results. In an attempt to assess the effect of donor age on graft survival and subsequent renal function, we analyzed our clinical results in 276 consecutive recipients of living related renal transplants spanning both the cyclosporine and the azathioprine eras, of whom a total of 44 recipients received kidneys from donors over 55 years old. All recipients were otherwise similar in age, race, haplotype mismatch, number of retransplants, and number of pretransplant transfusions, apart from an increased number of diabetics among the CsA-treated recipients of elderly kidneys (38% vs. 14%). The cumulative patient and graft survival rates at 1 and 5 years were independent of donor age whether CsA or AZA was utilized. Nor was the incidence of rejection or infection significantly different in the older donor group when compared with the younger cohort. Short-term and intermediate-term renal function, as assessed by serum creatinine, was however poorer but stable in the older donor group when compared with the younger one. The mean serum creatinine levels at 1 year in the CsA- and AZA-treated recipients of kidneys from older donors were 2.4 and 2.0 mg/dl, respectively, compared with 1.6 and 1.4 mg/dl, respectively, when the donor age was less than 55 years (P less than 0.001). Since renal function at the end of the first posttransplant year is considered a determinant of long-term graft survival, this is a cause for concern, but in view of the universal shortage of organs and the negligible morbidity to donors, renal transplantation from elderly living donors remains an acceptable practice. 相似文献
88.
A psychobiological perspective on the personality disorders 总被引:3,自引:0,他引:3
A preliminary but growing body of evidence supports the existence of genetic and biological substrates of personality, suggesting the utility of a psychobiological perspective on the personality disorders. The investigation of biological correlates of personality disorders can provide an empirical base to explore the relationship between biological predispositions and psychological function. The authors propose a psychobiological model based on dimensions of cognitive/perceptual organization, impulsivity/aggression, affective instability, and anxiety/inhibition. These dimensions span the DSM-III-R axis I and axis II disorders. The authors review phenomenological, genetic, and biological evidence in relation to each of these dimensions. Although such an approach remains heuristic, this model provides a promising vantage point from which to generate investigation of the development and treatment of the personality disorders. 相似文献
89.
Systemic administration of the phosphodiesterase inhibitor rolipram (0.05–10.0 mg/kg, IP) produced a rapid and dose-related
increase in the amplitude of the acoustic startle response in rats. The (−) isomer was more potent than the (+) isomer in
enhancing startle amplitude. Rolipram increased startle responses that were elicited by brief electrical stimulation of the
ventral cochlear nucleus or nucleus reticularis pontis caudalis, two brainstem relay nuclei of the startle neural circuit.
A low (5 μg) dose of rolipram produced an excitatory effect on startle following spinal (lumbar intrathecal) infusion but
not following supraspinal (lateral ventricle) infusion. Rolipram (0.5 mg/kg, IP) excitation of startle was not blocked by
drugs which differentially disrupt the release of monoamines (DSP4, reserpine + alpha-methylpara-tyrosine, reserpine + para-chloro-phenylalanine)
or by drugs which differentially block monoamine receptors (haloperidol, prazosin, idazoxan, cinanserin, or cyproheptadine).
The marked increase in startle seen following systemic rolipram injection is attributable, at least in part, on an action
in the lumbar spinal cord that directly or indirectly facilitates neural transmission along the reticulospinal component of
the startle reflex neural pathway. The startle reflex should be a useful behavioral test system for studying the mechanism
of action of rolipram and related compounds purported to selectively inhibit calmodulin-independent forms of phosphodiesterase. 相似文献
90.
Exercise training ameliorates progressive renal disease in rats with subtotal nephrectomy 总被引:7,自引:0,他引:7
To determine the effect of chronic exercise training on renal function in animals with moderate renal insufficiency, rats with 75% renal ablation were either exercise trained by swimming for two months or remained sedentary. Glomerular filtration rate was significantly higher in trained (1.89 +/- 0.07 ml/min) than in sedentary rats (1.52 +/- 0.11 ml/min). No change was observed in renal blood flow or the degree of hypertension. Proteinuria was reduced in trained (13.6 +/- 4.9 mg/24 hr) compared to sedentary animals (33.5 +/- 9.2 mg/24 hr). The degree of glomerulosclerosis was much less prominent in trained animals. Plasma, low-density lipoprotein cholesterol-levels and total triglycerides were reduced in trained compared to sedentary rats. This study suggests that chronic exercise training ameliorates the progression of renal disease and improves plasma lipids in rats with moderate renal insufficiency. The mechanism for this improvement in renal function appears to be independent of the influence of systemic blood pressure. 相似文献