全文获取类型
收费全文 | 20662篇 |
免费 | 1416篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 155篇 |
儿科学 | 700篇 |
妇产科学 | 573篇 |
基础医学 | 3281篇 |
口腔科学 | 484篇 |
临床医学 | 2213篇 |
内科学 | 4250篇 |
皮肤病学 | 438篇 |
神经病学 | 1924篇 |
特种医学 | 543篇 |
外科学 | 2281篇 |
综合类 | 138篇 |
一般理论 | 6篇 |
预防医学 | 1568篇 |
眼科学 | 336篇 |
药学 | 1335篇 |
中国医学 | 18篇 |
肿瘤学 | 1875篇 |
出版年
2023年 | 120篇 |
2022年 | 188篇 |
2021年 | 362篇 |
2020年 | 360篇 |
2019年 | 422篇 |
2018年 | 429篇 |
2017年 | 396篇 |
2016年 | 466篇 |
2015年 | 558篇 |
2014年 | 661篇 |
2013年 | 962篇 |
2012年 | 1328篇 |
2011年 | 1349篇 |
2010年 | 786篇 |
2009年 | 721篇 |
2008年 | 1160篇 |
2007年 | 1274篇 |
2006年 | 1174篇 |
2005年 | 1143篇 |
2004年 | 1091篇 |
2003年 | 972篇 |
2002年 | 896篇 |
2001年 | 364篇 |
2000年 | 287篇 |
1999年 | 313篇 |
1998年 | 256篇 |
1997年 | 217篇 |
1996年 | 173篇 |
1995年 | 162篇 |
1994年 | 136篇 |
1993年 | 145篇 |
1992年 | 212篇 |
1991年 | 199篇 |
1990年 | 210篇 |
1989年 | 215篇 |
1988年 | 211篇 |
1987年 | 197篇 |
1986年 | 160篇 |
1985年 | 187篇 |
1984年 | 144篇 |
1983年 | 129篇 |
1982年 | 95篇 |
1981年 | 80篇 |
1980年 | 84篇 |
1979年 | 122篇 |
1978年 | 100篇 |
1977年 | 108篇 |
1975年 | 84篇 |
1974年 | 99篇 |
1972年 | 77篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Results of a double blind study of 89-strontium therapy of skeletal metastases of prostatic carcinoma 总被引:5,自引:0,他引:5
Klaus Buchali Hans-Jacob Correns Michael Schuerer Dietmar Schnorr Hildegard Lips Karin Sydow 《European journal of nuclear medicine and molecular imaging》1988,14(7-8):349-351
Forty-nine patients were treated with either 3×75 MBq 89Sr or saline as placebo. Analysis of results 1 to 3 years after therapy revealed the ineffectiveness of 89Sr to relieve pain from metastases. Unexpectedly, a higher survival rate was found after Sr application (46% vs 4% after 2 years). Covariate analysis underlines the effect of 89Sr therapy on life expectation. 相似文献
52.
Lise Pedersen Susanne Holck Torben Schiødt Karin Zedeler Henning T. Mouridsen 《Breast cancer research and treatment》1989,14(1):91-99
Summary One hundred thirty-one breast carcinomas with medullary features, registered in the Danish Breast Cancer Cooperative Group from 1977–1982, have been histopathologically reviewed by two senior pathologists and classified as typical medullary carcinoma (TMC), atypical medullary carcinoma (AMC), and non-medullary carcinoma (NMC). Diagnostic criteria were based on those put forward by Ridolfiet al. and Fisheret al. The procedure was repeated with an interval of about one year by both pathologists. The diagnostic interobserver agreement was 72% with a Kappa of 0.55. The intraobserver agreement was 77% and 63% with Kappa values of 0.64 and 0.44, respectively. To see whether the observed inter- and intraobserver variability had any prognostic implications, diagnostic subgroups for both pathologists were analyzed with Kaplan Meier plots for recurrence-free survival (RFS) and with log rank tests. In the first evaluation pathologist 1 segregated a group of TMC with a significantly better RFS than for the NMC group, and pathologist 2 segregated a group of TMC with a corresponding strong trend. These findings could not, however, be reproduced in the second evaluation. The study indicates that the criteria of TMC and AMC as proposed by Ridolfiet al. need to be sharpened and simplified in order to reduce inter-and intraobserver variability. Larger studies with a control group of infiltrating ductal carcinomas are mandatory to elucidate the clinical importance of the diagnoses of Typical and Atypical Medullary Carcinoma of the breast. 相似文献
53.
Effects of alkyl chain length on the inhibition of NNK-induced lung neoplasia in A/J mice by arylalkyl isothiocyanates 总被引:4,自引:1,他引:3
Morse Mark A.; Eklind Karin I.; Amin Shantu G.; Hecht Stephen S.; Chung Fung-Lung 《Carcinogenesis》1989,10(9):1757-1759
Six homologous arylalkyl isothiocyanates were evaluated fortheir abilities to inhibit pulmonary adenomas induced by thetobacco-specific nitrosamine 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone(NNK) in A/J mice. Four consecutive daily doses (5 µmol/mouse)of phenyl isothiocyanate (PITC), benzyl isothiocyanate (BITC),phenethyl isothiocyanate (PETTC), 3-phenylpropyl isothiocyanate(PPITC), 4-phenylbutyl isothiocyanate (PBITC), 4-oxo-4-(3-pyridyl)-butylisothiocyanate (OPBITC) and corn ofl were administered to miceby gavage. Two hours following the final dosing, mice were administeredsaline or 10 µmol of NNK in saline i.p. Pulmonary adenomaswere counted at 16 weeks after NNK administration. The miceadministered only corn oil prior to NNK developed an averagemultiplicity of 9.2 tumors/ mouse. Pretreatment with PITC, BITCand OPBITC had no significant effects on NNK-induced lung neoplasia.However, PEITC pretreatment resulted in a 64% reduction of lungtumor multiplicity, but did not affect the percentage of micethat developed tumors. Both PPITC and PBITC decreased tumormultiplicity by 96% and the percentage of tumor-bearing animalsby >60%. These results, in conjunction with our previouswork, demonstrate a general trend of increasing inhibition ofNNK-induced lung neoplasia by arylalkyl isothiocyanates withincreasing alkyl chain length. This study also demonstratesthe remarkable inhibitory activities of PPITC and PBITC, twoisothiocyanates that had not previously been tested as chemopreventiveagents. 相似文献
54.
Spatial learning impairments in rats with selective immunolesion of the forebrain cholinergic system. 总被引:4,自引:0,他引:4
A monoclonal antibody to the low-affinity NGF receptor, 192 IgG, coupled to a cytotoxin, saporin, was recently introduced as an efficient selective neurotoxin for the NGFr-bearing cholinergic neurones in the rat basal forebrain. In the present study we report that an intracerebroventricular injection of this 192 IgG-saporin conjugate induces a severe, long-lasting spatial learning impairment, as assessed in the Morris water-maze task. This behavioural impairment was associated with 65-90% depletion of choline acetyltransferase activity (ChAT) in the hippocampus and cortex. ChAT activity associated with other cholinergic neurone systems in the brain (striatum, mesencephalon, spinal cord), was left virtually unaffected. This new immunotoxin holds great promise as a tool for selective and efficient lesions of the forebrain cholinergic system in functional and behavioural studies. 相似文献
55.
Andreas C Eriksson Per A Whiss Ulrika K Nilsson 《Blood coagulation & fibrinolysis》2006,17(5):359-368
Lysophosphatidic acid (LPA) and adrenaline are weak platelet activators considered important for thrombus formation, and were previously shown to synergistically increase platelet aggregation. Here we investigate synergistic activation by LPA and adrenaline when measuring platelet adhesion. Platelet-rich plasma from healthy blood donors together with adrenaline and/or LPA were added to protein-coated microplates. Platelets were allowed to adhere and the amount of adhesion detected enzymatically. The LPA and adrenaline combination induced a synergistic increase of platelet adhesion to a normally non-adhesive albumin surface. The degree of synergy varied markedly between individuals; these variations could not be explained by age, gender, blood type or different amounts of platelets, oxidized low-density lipoprotein, insulin or glucose in plasma. There was a trend indicating increased synergistic effect for platelets sensitive to adrenaline stimulation. The synergistic effect was blocked by the alpha2-adrenoceptor antagonist yohimbine and inhibited by the ADP scavenger system creatine phosphate/creatine phosphokinase and antibodies against alphaIIbbeta3. Furthermore, platelets adhering to albumin after adrenaline and LPA treatment expressed P-selectin. In conclusion, LPA and adrenaline act synergistically to increase alphaIIbbeta3-mediated platelet adhesion to albumin, dependent on alpha2-adrenoceptor signalling and platelet secretion. We also confirm that synergistic platelet activation achieved with LPA and adrenaline is highly donor dependent. 相似文献
56.
Relevance of stimulus duration for activation of motor and sensory fibers: implications for the study of H-reflexes and magnetic stimulation. 总被引:5,自引:0,他引:5
M Panizza J Nilsson B J Roth P J Basser M Hallett 《Electroencephalography and clinical neurophysiology》1992,85(1):22-29
Electric stimuli with durations of 0.5-1.0 msec are optimal for studies of H-reflexes. It is more difficult to obtain H-reflexes with shorter duration stimuli or with magnetic stimulation. In order to understand this behavior, we studied the excitation thresholds for motor and sensory fibers in the ulnar, median and tibial nerves using both electric and magnetic stimulation. For short duration electrical stimuli (0.1 msec) the threshold for motor fibers is lower than for sensory fibers. For longer duration electric stimuli (1.0 msec) the threshold for sensory fibers is lower. For magnetic stimulation the threshold for motor fibers is much lower than for sensory fibers. Thus, stimulus duration is a critical parameter for sensory fiber excitation, and current magnetic stimulators are not optimal. 相似文献
57.
58.
59.
Christina Frennesson Peter Jakobsson Ulla L. Nilsson 《Documenta ophthalmologica. Advances in ophthalmology》1995,91(1):9-16
A new approach designed to establish the most suitable area for eccentric viewing and to teach and train patients with severe age-related macular degeneration (AMD) to use the eccentric viewing technique is described. Using a computer and video display based system, as well as software written specifically for this purpose, we investigated and trained ten consecutive patients with AMD. The patients were 80.1 ± 5.6 years old, on average. All of them had an absolute central scotoma. Mean visual acuity was 0.035 ± 0.016. After 30 min of testing, instruction and reading on the screen, followed by 2.6 ± 0.69 one-hour training sessions, on average, with the low vision therapist, reading newspaper and book texts with the aid of hyperoculars or aplanatic systems and a very short reading distance, the patients achieved a reading speed of 58.9 ± 19.7 words/min, significantly (p<0.001) higher than the initial speed when reading on the screen, 11.5 ± 4.5 words/min. 相似文献
60.