全文获取类型
收费全文 | 19789篇 |
免费 | 905篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 270篇 |
儿科学 | 378篇 |
妇产科学 | 213篇 |
基础医学 | 2248篇 |
口腔科学 | 567篇 |
临床医学 | 1335篇 |
内科学 | 5069篇 |
皮肤病学 | 410篇 |
神经病学 | 1248篇 |
特种医学 | 776篇 |
外科学 | 3746篇 |
综合类 | 93篇 |
一般理论 | 2篇 |
预防医学 | 597篇 |
眼科学 | 219篇 |
药学 | 1404篇 |
中国医学 | 56篇 |
肿瘤学 | 2174篇 |
出版年
2023年 | 92篇 |
2022年 | 188篇 |
2021年 | 411篇 |
2020年 | 214篇 |
2019年 | 266篇 |
2018年 | 345篇 |
2017年 | 250篇 |
2016年 | 343篇 |
2015年 | 349篇 |
2014年 | 455篇 |
2013年 | 580篇 |
2012年 | 977篇 |
2011年 | 1150篇 |
2010年 | 694篇 |
2009年 | 557篇 |
2008年 | 1026篇 |
2007年 | 1069篇 |
2006年 | 1075篇 |
2005年 | 1081篇 |
2004年 | 1012篇 |
2003年 | 880篇 |
2002年 | 907篇 |
2001年 | 484篇 |
2000年 | 561篇 |
1999年 | 470篇 |
1998年 | 257篇 |
1997年 | 225篇 |
1996年 | 201篇 |
1995年 | 150篇 |
1994年 | 148篇 |
1993年 | 141篇 |
1992年 | 394篇 |
1991年 | 353篇 |
1990年 | 339篇 |
1989年 | 347篇 |
1988年 | 332篇 |
1987年 | 319篇 |
1986年 | 268篇 |
1985年 | 262篇 |
1984年 | 187篇 |
1983年 | 177篇 |
1982年 | 73篇 |
1981年 | 79篇 |
1979年 | 112篇 |
1978年 | 85篇 |
1977年 | 89篇 |
1974年 | 80篇 |
1972年 | 74篇 |
1970年 | 80篇 |
1969年 | 77篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
61.
Effects of chlorpromazine as a systemic vasodilator during cardiopulmonary bypass in neonates 总被引:1,自引:0,他引:1
Yutaka Imoto Hideaki Kado Munetaka Masuda Hisataka Yasui 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2002,50(6):241-245
OBJECTIVES: Vasodilator use during cardiopulmonary bypass is important in pediatric cardiac surgery, but the full range of their effects on hemodynamics remains to be clarified. We studied the effects of chlorpromazine, a potent alpha-blocking agent, in neonates. METHODS: Subjects were 60 neonates undergoing arterial switch operations for complete transposition of the great arteries with an intact ventricular septum. Of these, 37 received 2.1 to 6.5 mg/kg of chlorpromazine during cardiopulmonary bypass (CPZ group) and 23 received no vasodilator (control group). We then compared hemodynamic parameters between groups during and early after surgery. RESULTS: The systemic vascular resistance index and mean arterial pressure during cardiopulmonary bypass were significantly lower in the CPZ group (p < 0.05), but systolic pressure 15 minutes after cessation of cardiopulmonary bypass did not differ between groups. The rise in peripheral temperature during rewarming after hypothermia was significantly higher and the acid-base status 40 minutes after cardiopulmonary bypass less acidotic in the CPZ group. Urine output during cardiopulmonary bypass was higher in the CPZ group. CONCLUSIONS: Chlorpromazine effectively counteracts systemic vasoconstriction induced by cardiopulmonary bypass without serious side effects in neonatal cardiac surgery. 相似文献
62.
63.
Plasma volume estimation using indocyanine green with biexponential regression analysis of the decay curves 总被引:2,自引:0,他引:2
We studied seven analytical methods of estimating the plasma volume from the decay curves of indocyanine green. Fifteen volunteers received 1.0 mgkg−1 of the dye by intravenous injection and the plasma concentration was measured continuously using spectrophotometry. Plasma volumes were calculated using three single-regression methods (1-a, 1-b, 1-c) and four biexponential regression methods (2-a, 2-b, 2-c, 2-d). The means (SD) of 1-a, 1-b and 1-c were 39 (5.0), 44 (5.7) and 54 (11.5) mlkg−1 , respectively, and these were significantly different from each other (p < 0.05). The values for methods 2-b, 2-c and 2-d were similar to each other: 39 (4.6), 40 (4.1) and 40 (4.0) mlkg−1 , respectively. These required more than 3 min circulation or mixing time. When the time allowed for mixing was less than 3 min (method 2-a) the plasma volume was underestimated. We conclude that plasma volume estimation using indocyanine green and spectrophotometry is most accurate when the mixing time is adequate (3–5 min) and the decay curves are analysed using biexponential regression. 相似文献
64.
Cadherin dysfunction in a human cancer cell line: possible involvement of loss of alpha-catenin expression in reduced cell-cell adhesiveness. 总被引:37,自引:0,他引:37
Y Shimoyama A Nagafuchi S Fujita M Gotoh M Takeichi S Tsukita S Hirohashi 《Cancer research》1992,52(20):5770-5774
A human lung cancer cell line, PC 9, was analyzed to elucidate the molecular mechanisms of dysfunction of cadherin-mediated cell-cell adhesion in cancer. Although PC 9 cells strongly expressed E-cadherin at the cell membrane, which was indistinguishable immunochemically from functional E-cadherin, they did not show tight cell-cell adhesion and had reduced E-cadherin-mediated aggregation activity. Immunoprecipitation with E-cadherin and Western blot analysis revealed that PC 9 cells did not express alpha-catenin, a cadherin-associated protein, suggesting that this was the cause of the cadherin dysfunction in the cell line. In addition, Northern and Southern blot analyses disclosed homozygous deletion of part of the alpha-catenin gene, which might have resulted in the loss of alpha-catenin expression in PC 9 cells. 相似文献
65.
X Renming K Ishihara M Sasa H Ujihara T Momiyama Y Fujita N Todo T Serikawa J Yamada S Takaori 《European journal of pharmacology》1992,223(2-3):185-192
The effects of CNK-602A (N-[(6-methyl-5-oxo-3-thiomorpholinyl) carbonyl]-L-histidyl-L-prolinamide), a novel thyrotropin-releasing hormone related analog, were investigated on absence-like seizure and tonic convulsion in the spontaneously epileptic rat (SER), which is a genetically defined double-mutant. When CNK-602A of 0.2-1 mg/kg was given intravenously to the animal, there were no changes in the background EEG except for an increase in low-voltage fast waves concomitant with behavioral alertness. However, CNK-602A suppressed absence-like seizure and tonic convulsion in a dose-dependent manner for over 1 h. These antiepileptic effects of CNK-602A on both seizures were antagonized by pretreatment with haloperidol (1 mg/kg, i.p.). It was found, using a brain in vivo microdialysis method, that CNK-602A at a dose of 1 mg/kg, which inhibits the seizures, increased the release of dopamine in the caudate nucleus. These results suggest that CNK-602A inhibits the seizures of SER in a similar manner to thyrotropin-releasing hormone (TRH), probably by increasing the release of dopamine in the central nervous system. In addition, the antiepileptic effects of CNK-602A were more potent and lasted longer than those of TRH. 相似文献
66.
Takuo Fujita Masaaki Fukase Takao Shimada Hironosuke Yamamoto 《Journal of bone and mineral metabolism》1992,10(1):37-40
In addition to estrogen widely used all over the world for the prevention of postmenopausal osteoporosis, calcitonin and vitamin
D derivatives are commonly employed to treat established osteoporosis at higher age in Japan. In order to critically assess
the usefulness of vitamin D derivatives and calcitonin alone or in combination on the advancement of vertebral deformity at
higher age, 32 osteoporotic patients with vertebral deformity with the mean age of 79 were randomly divided into 4 groups
with indistinguishable age and severity of the vertebral deformity. Group 1 served as the control without specific medications
for osteoporosis. Group 2 was treated with 10 units elcatonin (eel calcitonin derivative) injected intramuscularly twice a
week. Group 3 was given 0.75 to 1.5μg/day 1α (OH) vitamin D3 orally. Group 4 was given a combination of treatments used in Groups 2 and 3.
In the lateral X-ray film of the spine taken prior to the test and every 6 months thereafter, the shape of the vertebral body
T8 through L4 was monitored by measuring the anterior, central and posterior heights. Decrease of the vertebral height ratio; anterior
or middle height/posterior or adjacent intact posterior height, by more than 20% of the original value or from above to below
0.80 both appeared to be inhibited during administration of 1α (OH) vitamin D3. Such effect seems to be augmented by simultaneous administration of elcatonin. Actual decrease of vertebral height ratio
values and the per cent fall from the original value significantly less in Groups 3 and 4 than in Group 1. Development of
vertebral deformity assessed by the changes of the vertebral height thus appears to decrease during treatment with 1α (OH) vitamin D3 especially together with calcitonin in established osteoporosis. 相似文献
67.
68.
H Hanyu H Arai H Katsunuma R Fujita C Tomori 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1991,28(2):160-165
A neuroradiological study of crossed cerebellar atrophy (CCA) was performed using X-ray CT in 103 patients suffering from unilateral supratentorial cerebrovascular diseases. CCA was demonstrated in 9 (8.7%) of 103 patients. No difference between the occurrence of CCA in cerebral hemorrhage and that in cerebral infarction was found. CCA was seen in the chronic stage of cerebrovascular disease more than 3 years since stroke occurrence, and was found to be present more frequently and to a greater extent 7 years later. No correlation between the site of bleeding and the occurrence of CCA was found. Trans-synaptic degeneration of the corticopontocerebellar tract was considered in CCA following putaminal and combined hemorrhage involving an internal capsule lesion. However, in thalamic hemorrhage, retrograde degeneration within the cerebellorubrothalamic tract was presumed. CCA following cerebral infarction was seen in patients with massive lesions in the territory of the middle cerebral artery. Multivariate analysis showed that lesions of the parietal and frontal lobes appeared to greatly contribute to the development of CCA. As the degeneration and atrophy in the thalamus on the side of the lesion appeared early and frequently, it was suggested that retrograde degeneration of the cerebellorubrothalamic tract participated, in addition to anterograde corticopontocerebellar tract degeneration, in CCA following middle cerebral artery infarction. It is likely that CCA is caused by both transsynaptic degeneration of the corticopontocerebellar tract and the cerebellorubrothalamic tract. 相似文献
69.
Ishizaki K.; Yoon D. M.; Yoshida N.; Yamazaki M.; Arai K.; Fujita T. 《British journal of anaesthesia》1995,75(5):636-638
We have studied the effect of intrathecal administration of N-methyl-D-
aspartate (NMDA) receptor antagonists on the minimum alveolar anaesthetic
concentration (MAC) of isoflurane in rats. In Wistar rats fitted with
indwelling intrathecal catheters, we determined the MAC of isoflurane after
administration of a competitive NMDA receptor antagonist, APV (0.01, 0.1,
1.0, 10, 30 micrograms), a non-competitive NMDA receptor antagonist, MK801
(0.1, 1.0, 10, 30 micrograms). NMDA (0.01, 0.1, 1.0, 10, 30 micrograms) and
saline. APV at all doses except 0.01 micrograms decreased MAC by 17.1-32%
(P < 0.001 and P < 0.0001). Although MK801 at 10 and 30 micrograms
reduced MAC by 24.3-31.7% (P < 0.001 and P < 0.0001), lower doses did
not affect MAC. Intrathecal administration of NMDA reversed these decreases
in MAC, but not to control values with APV 10 and 30 micrograms and MK801
30 micrograms. We suspect that NMDA and NMDA receptor antagonists play
important roles in the spinal cord in determining the MAC of isoflurane.
相似文献
70.
Hideaki Anai Yoshihiko Maehara Tatsuo Oshiro Hideo Baba Hiroyuki Orita Toshiro Okuyama Keizo Sugimachi 《Journal of surgical oncology》1993,53(3):204-207
In 268 of the 1,115 patients (24.0%) with gastric cancer who underwent a curative resection in our clinics, the tumor was located in the middle third of the stomach. The clinicopathological features and prognosis of these patients were divided into two groups, according to site of the tumor: anterior wall (n = 58) vs. other sites (n = 210). Clinicopathological factors did not differ between the two groups. The survival time for patients with a tumor in the anterior group was shorter than that for patients with a tumor in other areas (P < 0.05). The five-year survival rate was 79.3% for patients with an anterior tumor and 91.9% for those with a tumor at a different site. A multivariate analysis indicated lymph node metastasis, serosal invasion, and anterior wall location to be independent prognostic factors indicative of a poor prognosis when the tumor was located in the middle third of the stomach. For such patients, close follow-up is needed to detect possible recurrences. © 1993 Wiley-Liss, Inc. 相似文献