全文获取类型
收费全文 | 48951篇 |
免费 | 3186篇 |
国内免费 | 188篇 |
专业分类
耳鼻咽喉 | 524篇 |
儿科学 | 1231篇 |
妇产科学 | 860篇 |
基础医学 | 6397篇 |
口腔科学 | 1252篇 |
临床医学 | 4749篇 |
内科学 | 9966篇 |
皮肤病学 | 725篇 |
神经病学 | 4778篇 |
特种医学 | 2552篇 |
外国民族医学 | 6篇 |
外科学 | 7217篇 |
综合类 | 592篇 |
一般理论 | 40篇 |
预防医学 | 4018篇 |
眼科学 | 1199篇 |
药学 | 2925篇 |
中国医学 | 69篇 |
肿瘤学 | 3225篇 |
出版年
2023年 | 206篇 |
2022年 | 348篇 |
2021年 | 807篇 |
2020年 | 612篇 |
2019年 | 811篇 |
2018年 | 952篇 |
2017年 | 773篇 |
2016年 | 914篇 |
2015年 | 1050篇 |
2014年 | 1469篇 |
2013年 | 2043篇 |
2012年 | 3102篇 |
2011年 | 3285篇 |
2010年 | 1866篇 |
2009年 | 1708篇 |
2008年 | 3056篇 |
2007年 | 3144篇 |
2006年 | 3108篇 |
2005年 | 3036篇 |
2004年 | 2843篇 |
2003年 | 2758篇 |
2002年 | 2655篇 |
2001年 | 619篇 |
2000年 | 573篇 |
1999年 | 636篇 |
1998年 | 601篇 |
1997年 | 468篇 |
1996年 | 421篇 |
1995年 | 402篇 |
1994年 | 322篇 |
1993年 | 294篇 |
1992年 | 370篇 |
1991年 | 338篇 |
1990年 | 310篇 |
1989年 | 325篇 |
1988年 | 292篇 |
1987年 | 308篇 |
1986年 | 279篇 |
1985年 | 300篇 |
1984年 | 305篇 |
1983年 | 292篇 |
1982年 | 318篇 |
1981年 | 297篇 |
1980年 | 263篇 |
1979年 | 225篇 |
1978年 | 233篇 |
1977年 | 195篇 |
1976年 | 168篇 |
1975年 | 177篇 |
1974年 | 183篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Human trophoblast and choriocarcinoma expression of the growth
factor pleiotrophin attributable to germ-line insertion of
an endogenous retrovirus 下载免费PDF全文
102.
Diagnostic performance of nocturnal penile tumescence studies in healthy, dysfunctional (impotent), and depressed men 总被引:1,自引:0,他引:1
M E Thase C F Reynolds J R Jennings S R Berman P R Houck J R Howell E Frank D J Kupfer 《Psychiatry research》1988,26(1):79-87
Nocturnal penile tumescence (NPT) studies were evaluated in 17 men with a clinical diagnosis of organic erectile dysfunction in comparison to age-matched healthy controls (n = 17) and depressed men (n = 17). The dysfunctional group had significantly fewer NPT episodes and reduced maximal penile tip changes when compared to healthy controls and depressed patients. Further, the dysfunctional group had significantly diminished erectile fullness and reduced penile rigidity. Diagnostic performance of polygraphic (night 1) and visual inspection (nights 2 or 3) components of the NPT protocol were examined in these criterion groups. A diagnostic classification based on polygraphic measures successfully discriminated 73.5% of dysfunctional and healthy control subjects, but classified 47% of depressives in the dysfunctional range. Use of visual inspection indices correctly identified 88% of the dysfunctional sample and 94% of normal controls, and reduced the "false-positive" rate in depression to only 18%. Results support the diagnostic utility of NPT studies, particularly when enhanced by visual inspection procedures. Nevertheless, the presence of major depression may confound interpretation of such studies. 相似文献
103.
104.
Alan R. Frank Patricia L. Sitlington Rori Carson 《Journal of developmental and physical disabilities》1992,4(1):37-50
The parents of 14 individuals with severe/profound mental disabilities were interviewed one and three years after their children graduated or aged out of high school. Two categories of information were sought concerning the adult adjustment of these individuals. General status variables included marital status, place of residence, agencies contacted concerning employment opportunities, financial resources, leisure activities, means of transportation, sources of help in resolving problems, and amount of postsecondary training. Employment variables included location of employment, wages, number of hours worked per week, and job benefits received. Results indicated that three years after exiting high school, all participants were very dependent upon others for housing, transportation, and financial assistance. Ten of the 14 individuals were employed 3 years after exiting high school, all in sheltered workshops. 相似文献
105.
David V. Gauvin Bradley D. Youngblood Frank A. Holloway 《Alcoholism, clinical and experimental research》1992,16(2):336-341
Twenty male Sprague-Dawley rats were trained to discriminate pentylenetetrazole (PTZ, 15 mg/kg, intraperitoneally) from saline (SAL) under a drug discrimination procedure. Test sessions were conducted with 10 randomly selected subjects. Tests with various doses of PTZ resulted in a dose-dependent increase in the percentage of total session responses emitted on the PTZ-appropriate lever without a significant change in response rates across a wide range of test PTZ doses. Rats did not generalize the PTZ stimulus to ethanol (ETOH) up to ETOH test doses that completely suppressed responding. High acute ETOH doses (2, 3, and 4 g/kg) administered at various time points prior to discrimination test sessions engendered responding on the PTZ-appropriate level in a quantitative fashion, that was dose- and time-dependent. This acute ETOH delayed effect from these high doses replicates our previously published study using a Drug 1-Drug 2 discrimination task with Chlordiazepoxide and PTZ. More importantly, we suggest that the present behavioral assay may be a sensitive animal analogue of human "hangover" phenomena. 相似文献
106.
L C Müller G M Salzer D zur Nedden R Frank E Müller-Holzner 《The Thoracic and cardiovascular surgeon》1992,40(2):82-86
A multimodal therapy concept for small-cell lung cancer, which for patients with established pretherapeutic homolateral lymph-node metastases (N2) prescribes induction chemotherapy with subsequent resection as well as supplemental chemo- and radiotherapy, provided the opportunity to evaluate histologically the radiological diagnoses "complete remission" and "partial remission" using resection specimens. In 17 patients a 75% to 100% reduction in tumor size was achieved according to radiological diagnosis. Predictions of "no evidence of disease" or "evidence of disease" were only correct in ten cases. In the remaining seven cases, histology showed the radiological findings to be incorrect. This gives a 77% sensitivity for radiological diagnosis with no specificity. Moreover, differentiation between therapy effect on the primary tumor and on the N2 metastases gives similar results: sensitivity 64% and 67% respectively, specificity 33% and 25% respectively. It is concluded that, particularly after the tumor responds well to therapy, radiological techniques are unsuitable for establishing a diagnosis of "no evidence of disease" or "evidence of disease" in small-cell lung cancer. This is because on the one hand the radiological methods available do not permit clear differentiation between vital tumor tissue and necrosis or fibrosis, while on the other hand groups of vital tumor cells beyond the resolution power of X-ray technology will escape detection. 相似文献
107.
108.
Biochemical characterisation of para-aminophenol-induced nephrotoxic lesions in the F344 rat 总被引:5,自引:0,他引:5
Kevin P. R. Gartland Frank W. Bonner John A. Timbrell Jeremy K. Nicholson 《Archives of toxicology》1989,63(2):97-106
The acute biochemical effects of the nephrotoxin p-aminophenol (PAP) were studied in detail using a combination of conventional bioanalytical and 1H-NMR spectroscopic methods. Dosing PAP (25–100 mg/kg) to male F344 rats resulted in a dose-related proximal nephropathy with consequent elevations in urinary enzymes, glucose, and urine total protein as shown by conventional methodology. 1H-NMR spectroscopy at 400 MHz of urine from PAP-treated rats also revealed a characteristic glycosuria, with concomitant amino aciduria. The increased excretion of these compounds indicates functional defects in the proximal tubule and reduced solute reabsorption efficiency. In addition, 1H-NMR urinalysis and conventional enzymatic analysis showed a dose-related lactic aciduria. Other changes detected by 1H-NMR included a dose-related reduction in the excretion of citrate (confirmed by a conventional biochemical method) and an increase in the excretion of acetate. The degree of abnormalities shown by 1H-NMR urinalysis agreed well with histopathological observations and conventional biochemical indices of nephrotoxicity. 1H-NMR urinalysis therefore serves to highlight changes in the excretion of low MW urine components not routinely studied by conventional biochemical analysis.Abbreviations ALP
alkaline phosphatase
- APAP
paracetamol
- BUN
blood urea nitrogen
- GFR
glomerular filtration rate
- GOT
glutamate oxaloacetate transaminase
- LAP
leucine aminopeptidase
- LDH
lactate dehydrogenase
- MW
molecular weight
- NAG
N-acetyl--D-glucosaminidase
- PAP
p-aminophenol
- ppm
parts per million
- TMAO
trimethylamine N-oxide
- UFR
urine flow rate 相似文献
109.
The liver regulates T-cell homeostasis, induces T-cell tolerance, and supports intrahepatic T-cell responses against hepatotropic pathogens. Many data from clinical and preclinical systems provide supportive evidence for these diverse roles of the liver in modulating peripheral (systemic, mucosal, and intrahepatic) T-cell immunity. Little information is available on the cellular and molecular mechanisms that mediate the dual role of the liver in tolerizing T-cell responses and in supporting intrahepatic priming of T-cell responses. Understanding these immunoregulatory effects in the liver may offer insight into clinically relevant immunopathologies of this organ. 相似文献
110.
Michael Schirner Frank Herzberg Roland Schmidt Michael Streit Michael Schoning Michael Hummel Christine Kaufmann Eckhard Thiel Ernst-Dieter Kreuser 《Clinical & experimental metastasis》1997,16(5):427-435
The integrin 51 seems to be the most relevant receptor of tumor cells for binding to fibronectin. Although numerous studies suggest a role of tumor cell fibronectin interaction in tumor metastasis, differential integrin expression on tumor cells has, however, not been correlated with metastatic capabilities. We addressed this question by transfection of the integrin 51 cDNA into HT-29 human colon carcinoma cells which led to de novo expression of functional integrin 51. Similar to other reports, expression of the integrin 51 in HT-29 tumor cells exerted an inhibitory action on cell proliferation as indicated in our study by formation of fewer colonies in soft agar. The tumor growth inhibitory property of the integrin 51 was also shown by reduction of subcutaneous xenograft growth in nude mice to approximately 50% of that of control transfectants. For the first time, we found that several clones of integrin 5 subunit transfectants displayed dramatically reduced formation of lung colonies and cutaneous metastasis after intravenous injec-tion into nude mice. While most animals inoculated with control transfectant cells formed macroscopically visible lung colonies ranging from 12.6 ± 2.6 to 22.0 ± 6.6 (mean colony number ± SEM), mice inoculated with HT-29 cell clones expressing the integrin a5b1 were almost completely free of lung colonies (ranging from 0.0 ± 0 to 0.2 ± 0.1). Our results imply that integrin 51 expression inhibits circulating tumor cells in pursuing late steps of the metastatic process as represented by the artificial metastasis (lung colonisation) model. © Rapid Science Ltd. 相似文献