全文获取类型
收费全文 | 215953篇 |
免费 | 9911篇 |
国内免费 | 388篇 |
专业分类
耳鼻咽喉 | 3450篇 |
儿科学 | 7642篇 |
妇产科学 | 5366篇 |
基础医学 | 30838篇 |
口腔科学 | 6437篇 |
临床医学 | 16747篇 |
内科学 | 40596篇 |
皮肤病学 | 5452篇 |
神经病学 | 20096篇 |
特种医学 | 10467篇 |
外国民族医学 | 35篇 |
外科学 | 34363篇 |
综合类 | 1256篇 |
现状与发展 | 1篇 |
一般理论 | 100篇 |
预防医学 | 12641篇 |
眼科学 | 5272篇 |
药学 | 14126篇 |
中国医学 | 389篇 |
肿瘤学 | 10978篇 |
出版年
2023年 | 927篇 |
2021年 | 1850篇 |
2020年 | 1595篇 |
2019年 | 2012篇 |
2018年 | 3674篇 |
2017年 | 3092篇 |
2016年 | 4137篇 |
2015年 | 4584篇 |
2014年 | 5081篇 |
2013年 | 7024篇 |
2012年 | 10889篇 |
2011年 | 10297篇 |
2010年 | 5982篇 |
2009年 | 5174篇 |
2008年 | 9960篇 |
2007年 | 10905篇 |
2006年 | 10889篇 |
2005年 | 11153篇 |
2004年 | 10423篇 |
2003年 | 10237篇 |
2002年 | 9875篇 |
2001年 | 7721篇 |
2000年 | 7731篇 |
1999年 | 6795篇 |
1998年 | 2140篇 |
1997年 | 1826篇 |
1996年 | 1503篇 |
1995年 | 1208篇 |
1994年 | 1139篇 |
1993年 | 1067篇 |
1992年 | 3407篇 |
1991年 | 3268篇 |
1990年 | 3198篇 |
1989年 | 2982篇 |
1988年 | 2663篇 |
1987年 | 2532篇 |
1986年 | 2395篇 |
1985年 | 2263篇 |
1984年 | 1715篇 |
1983年 | 1377篇 |
1979年 | 1684篇 |
1978年 | 1177篇 |
1977年 | 1020篇 |
1975年 | 1265篇 |
1974年 | 1297篇 |
1973年 | 1203篇 |
1972年 | 1237篇 |
1971年 | 1174篇 |
1970年 | 1035篇 |
1969年 | 948篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
131.
A E van der Merwe F J Mattheyse M Bedford P D van Helden D J Rossouw 《Burns : journal of the International Society for Burn Injuries》1990,16(3):193-197
Cultured keratinocytes were used as allografts on burn wounds in two patients. In both patients successful covering of the wounds was obtained. DNA fingerprinting of the epidermis covering the wounds 21 days later showed that the cultured keratinocytes were replaced by the patients' cells. 相似文献
132.
Neuromuscular junctions (NJs) of fin muscles of teleostean fishes, Lebistes reticulatus, were ultrastructurally analyzed during 60 min of chronic exercise and a subsequent period of 90 min of induced recovery. NJs from 30-min-exercised fishes showed an almost complete depletion of synaptic vesicles (SVs), corresponding to 83% of SV consumption; 76% of axon terminals were branched at the end of this period. During the recovery period, it was possible to observe the reversibility of the changes induced by the exercise and the transitory events that lead to the reacquirement of the normal NJ morphology. After 15 min of rest, SV population increased to a value of 54.6 SVs/micron2 and the percentage of branched axons was 66.5%. At 60 min of recovery the number of SVs reached a value of 84.6 SVs/micron2. The SV population was fully reestablished at 80 min of rest, while the percentage of branched axons was found within normal ranges after 90 min of recovery. These results demonstrate that chronic exercise induced physiological depletion of NJ SVs and other axon terminal morphological changes, as well as that postexercise rest induces the reestablishment of the normal NJ morphology. 相似文献
133.
D. Lothschütz M. Jennewein S. Pahl H.F. Lausberg A. Eichler W. Mutschler R.G. Hanselmann M. Oberringer 《Inflammation research》2002,51(8):416-422
OBJECTIVE AND DESIGN: Inflammatory and tumorous bronchi were screened in order to obtain new tumor relevant cytogenetic parameters. MATERIAL OR SUBJECTS: Bronchial cells of 32 patients were cultivated by standard cell culture procedures. METHODS: Tetraploidy and aneuploidy was determined by enumeration of chromosome 7 and 8 versus the number of centrosomes. The resulting data were correlated with histopathological data. RESULTS: Tetra- and aneuploidy of epithelial cells were detectable in 76% of tumor cell cultures, 75% of high grade inflammatory tissues and 40% of non- and low grade-inflammatory tissues. Additionally, we observed centrosome hyper-amplification and multipolar mitoses not only in the tumor but also in the early stages of inflammation. CONCLUSION: Inflammatory bronchi already show tumor-specific features and may consequently represent the preliminary genetic stage of cancer development in bronchi. 相似文献
134.
135.
136.
The experimental infection of immunocompetent and immunodeficient athymic mice with an avirulent encephalitogenic Toxoplasma strain (DX strain) was employed to study the ensuing encephalitic process by use of histological and immunocytochemical methods. In the acute phase of the infection Toxoplasma cysts and tachyzoites were accompanied by an infiltrate composed of macrophages, CD4+ and CD8+ T cells. In the chronic stage a granulomatous encephalitis developed. In contrast to immunocompetent NMRI mice, athymic nude NMRI mice died 3 weeks post-infection because of a generalized toxoplasmosis with predominant involvement of the brain. A salient feature of murine Toxoplasma encephalitis was up-regulation of class I and II major histocompatibility complex (MHC) gene products. Class I antigen was widely expressed on microglial cells and astrocytes. Class II antigen was only expressed on microglial cells despite a considerable astrogliosis. Our results indicate a differential expression of MHC-determined antigens on brain cells in acute and chronic murine Toxoplasma encephalitis. 相似文献
137.
138.
J M Debets R Kampmeijer M P van der Linden W A Buurman C J van der Linden 《Critical care medicine》1989,17(6):489-494
Tumor necrosis factor (TNF) cachectin has been implicated as an important host mediator responsible for shock and multiple organ failure (MOF) observed during sepsis. Using a sensitive enzyme-linked immunosorbent assay, we measured plasma TNF levels in 43 septic patients suffering from a broad range of diseases. Measurements were taken on the day that sepsis was diagnosed. Eleven patients had detectable TNF plasma levels ranging from 10 to 100 pg/ml (TNF-positive group); in 32 patients circulating TNF could not be detected (TNF-negative group). The groups did not differ significantly as to age, underlying disease, percentage positive bacteremia and bacteriologic profile, sepsis score, and extent of MOF. Eight (73%) of 11 TNF-positive patients died from sepsis during ICU stay, vs. 11 (34%) of 32 TNF-negative patients (p less than .05). This study demonstrates that sepsis is accompanied by detectable circulating TNF in 25% of the cases, and for these patients mortality is twice that for comparable TNF-negative patients. 相似文献
139.
F Elferink W J van der Vijgh W W ten Bokkel Huinink J B Vermorken I Klein B Winograd M K Knobf G Simonetti H E Gall J G McVie 《British journal of cancer》1987,56(4):479-483
Pharmacokinetics of the cis-platin analog ethylenediaminemalonatoplatinum(II) (JM-410) was studied in 28 cycles of 19 patients during the phase I study of this drug. The drug was administered intravenously by short-term (10-60 min) infusion. Doses ranged from 20 to 1,200mg m-2. JM-40 was determined in plasma ultrafiltrate and urine by HPLC. Platinum (Pt) concentrations were determined in plasma, plasma ultrafiltrate, urine and red blood cells by atomic absorption spectrometry up to 5 days after administration of the drug. Ultrafilterable Pt could be determined up to 45 days after the infusion in one patient sampled over such a long period. Pharmacokinetics of JM-40 showed a linear behaviour. The final half-life of total Pt in plasma was 4.1 +/- 0.9 days. The disposition of JM-40 was similar to that of ultrafilterable Pt in respect to t1/2 alpha (10 and 13 min), t1/2 beta (44 and 57 min), volumes of distribution Vc (11 and 121) and Vss (17 and 201), systemic clearance (256 and 223 ml min-1), renal clearance (69 and 73 ml min-1) and metabolic clearance (183 and 154 ml min-1). During the first 6 h 27 +/- 9% of the administered dose was excreted as JM-40. Cumulative platinum excretion in the urine amounted to 29 +/- 13% and 60 +/- 13% over the first 6 h, 24 h and 5 days, respectively. The uptake of platinum in red blood cells was limited, comprising only 0.24 +/- 0.12% of the administered dose. Although JM-40 and carboplatin are structurally closely related, pharmocokinetics and toxicity of JM-40 were more similar to cis-platin than to carboplatin. 相似文献
140.
The simultaneous determination of cerebrospinal fluid and plasma adenosine deaminase activity as a diagnostic aid in tuberculous meningitis 总被引:1,自引:0,他引:1
P R Donald C Malan A van der Walt J F Schoeman 《Suid-Afrikaanse tydskrif vir geneeskunde》1986,69(8):505-507
The simultaneous determination of cerebrospinal fluid (CSF) and plasma adenosine deaminase (ADA) activity was evaluated as a diagnostic aid in tuberculous meningitis (TBM). CSF and plasma ADA activity were determined in four groups of patients: (i) a 'no meningitis' group of 174 children investigated for possible meningitis, but found to be uninfected; (ii) an aseptic meningitis group of 40 children; (iii) a bacterial meningitis group of 31 children; and (iv) a TBM group of 27 patients (24 children and 3 adults). CSF ADA alone was determined in a further 23 children with aseptic meningitis, 19 with bacterial meningitis and 13 children and 7 adults with TBM. Both the CSF/plasma ADA ratio and the absolute CSF ADA activity were raised in TBM (mean values 0,24 and 12,61 U/I respectively) and bacterial meningitis (mean values 0,59 and 15,43 U/I respectively), but not in the aseptic meningitis group (mean values 0,06 and 2,00 U/I) or the 'no meningitis' group (mean values 0,04 and 1,51 U/I). Both values will distinguish TBM from aseptic meningitis, but do not appear to hold any marked advantages over conventional CSF criteria in the diagnosis of TBM. 相似文献