全文获取类型
收费全文 | 1695951篇 |
免费 | 123890篇 |
国内免费 | 3785篇 |
专业分类
耳鼻咽喉 | 21735篇 |
儿科学 | 55659篇 |
妇产科学 | 46174篇 |
基础医学 | 241308篇 |
口腔科学 | 48753篇 |
临床医学 | 151355篇 |
内科学 | 333814篇 |
皮肤病学 | 38664篇 |
神经病学 | 131188篇 |
特种医学 | 63882篇 |
外国民族医学 | 242篇 |
外科学 | 257370篇 |
综合类 | 38953篇 |
现状与发展 | 4篇 |
一般理论 | 531篇 |
预防医学 | 124256篇 |
眼科学 | 40222篇 |
药学 | 123664篇 |
7篇 | |
中国医学 | 4480篇 |
肿瘤学 | 101365篇 |
出版年
2021年 | 12792篇 |
2019年 | 13528篇 |
2018年 | 19957篇 |
2017年 | 15218篇 |
2016年 | 16620篇 |
2015年 | 18965篇 |
2014年 | 26222篇 |
2013年 | 37955篇 |
2012年 | 52810篇 |
2011年 | 55504篇 |
2010年 | 32785篇 |
2009年 | 30703篇 |
2008年 | 51583篇 |
2007年 | 54879篇 |
2006年 | 55336篇 |
2005年 | 52606篇 |
2004年 | 50798篇 |
2003年 | 48203篇 |
2002年 | 46417篇 |
2001年 | 91809篇 |
2000年 | 93641篇 |
1999年 | 76979篇 |
1998年 | 19723篇 |
1997年 | 17268篇 |
1996年 | 17391篇 |
1995年 | 16743篇 |
1994年 | 15289篇 |
1993年 | 14071篇 |
1992年 | 57381篇 |
1991年 | 55270篇 |
1990年 | 52971篇 |
1989年 | 50747篇 |
1988年 | 46131篇 |
1987年 | 44937篇 |
1986年 | 42226篇 |
1985年 | 39988篇 |
1984年 | 29349篇 |
1983年 | 24908篇 |
1982年 | 13898篇 |
1979年 | 25529篇 |
1978年 | 17574篇 |
1977年 | 14906篇 |
1976年 | 13874篇 |
1975年 | 14563篇 |
1974年 | 17630篇 |
1973年 | 16945篇 |
1972年 | 15673篇 |
1971年 | 14453篇 |
1970年 | 13431篇 |
1969年 | 12517篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
133.
H. Nilsson J. Johansson K. Svanberg S. Svanberg G. Jori E. Reddi A. Segalla D. Gust A. L. Moore T. A. Moore 《British journal of cancer》1997,76(3):355-364
The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated. 相似文献
134.
Abstract Perioscan requires a plaque sample to detect the presence of enzymes capable of degrading N-benzoyl-DL-arginine-2-naphthylamide (BANA) from relatively few anaerobic periodontal pathogens. Periocheck assays the presence of neutral proteases in crevicular fluid. The aim of this study was to compare these test kits with traditional clinical methods of detecting periodontal disease and to monitor the ability of the kits to reflect the response to initial therapy. 19 patients with moderately severe chronic periodontitis were seen before and after a course of oral hygiene and root instrumentation consisting of 4 appointments. Clinical measurements and test assays were collected at 5 diseased sites and 2 healthy sites in each subject. Complete data from 125 sites were available for statistical analysis. At baseline Periocheck had a sensitivity of 88% and a specificity of 61% whereas Perioscan had a sensitivity of 99% and a specificity of 55%, when related to the clinical diagnosis. A composite clinical assessment, based on improvement or deterioration of one whole unit change of the subjective clinical indices and 2mm changes or greater in probing depth or probing attachment level, revealed 75 sites which improved following treatment, whereas 45 sites did not change and 5 sites deteriorated. The probability that the tests agreed with the clinical outcome after treatment, was calculated as 50.4% for Periocheck and 52% for Perioscan. The diagnostic kits did not reliably reflect the clinical assessment of periodontal disease in the cross sectional study, or the outcome following treatment. 相似文献
135.
136.
This study aimed at identifying the signal(s) that elicit myositis-induced neuroplastic changes in background activity and responsiveness of spinal neurones. It is based on previous data suggesting that in dorsal horn neurones, responsiveness to peripheral input on one hand and background activity on the other are probably controlled by different mechanisms. In anaesthetized rats, myositis was induced in the gastrocnemius-soleus muscle and the activity of single dorsal horn neurones was recorded in segment L3. Impulse traffic and axoplasmatic transport in dorsal roots L4 and L5 were selectively blocked by lignocaine or vinblastine for various time periods relative to the induction of the myositis. The results show that the main triggering signal for the myositis-induced changes in both responsiveness and background activity is the altered impulse activity in primary afferent fibres. In contrast, 'no axonally transported chemical signal controlling the discharge behaviour of dorsal horn neurones was found. However, the time course of the electrical signals that cause the myositis-induced changes in background activity and responsiveness is different. For changes in responsiveness, a rather narrow time window of 2 h directly after induction of the myositis existed, during which the impulses from the inflamed muscle must reach the spinal cord. Accordingly, to prevent the increase in responsiveness, the electrical input had to be blocked during the first 2 h; a block of the same duration at another time had no effect. The change in background activity seems to be due to a continuous input from the inflamed muscle which adds up over the hours. Therefore, with regard to background activity, blocking the electrical signals is effective at any time, but only a block of long duration has a significant effect. 相似文献
137.
T F Kruger J P Van der Merwe H J Odendaal F S Stander G M Grobler V A Hulme E L Erasmus K Coetzee M L Windt Y Swart 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(12):634-636
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate. 相似文献
138.
G Hasselgren R Jerre M Ullman A T?rnvall S Edshage 《The Journal of hand surgery, European volume》1990,15(1):35-39
Eleven patients with lunatomalacia were treated by excision of the lunate and instillation of liquid silicone. The silicone vulcanised and formed an in-situ molded prosthesis. The patients were reexamined after a mean of 7.1 years. Four patients were pain-free and two had pain only at work; three had not been improved by the operation and two had undergone arthrodesis. The patients with good results all belonged to group IV pre-operatively. Surprisingly, no patient showed any sign of silicone synovitis, although all the prostheses except one had either fractured or deformed. The reasons for this are discussed and the indications for the operation established. 相似文献
139.
1. Effects of a novel imidazoindole derivative on cholinergic function were studied in isolated tissue preparations. 2. The compound demonstrated a dose-dependent (10(-11)-10(-9) potentiation (20-60%) of acetylcholine induced tension in guinea pig ileal tissue. 3. Increases in the size of end-plate potentials and nerve evoked muscle twitches were observed in frog nerve-skeletal muscle preparations. 4. Cholinesterase activity was not inhibited. 5. The results suggest that the compound has actions at the post-synaptic muscarinic receptor complex in smooth muscle and causes pre-synaptic increases in ACh release at the neuromuscular junction. 相似文献
140.
We report a case of recurrent calculi in a Kock pouch continent urinary diversion. An open operation was avoided by successfully excising the Marlex mesh and removing it with the associated calculi in an endoscopic fashion. 相似文献