全文获取类型
收费全文 | 344114篇 |
免费 | 22413篇 |
国内免费 | 7714篇 |
专业分类
耳鼻咽喉 | 4073篇 |
儿科学 | 9609篇 |
妇产科学 | 6556篇 |
基础医学 | 27587篇 |
口腔科学 | 7939篇 |
临床医学 | 37840篇 |
内科学 | 43187篇 |
皮肤病学 | 4564篇 |
神经病学 | 19395篇 |
特种医学 | 7902篇 |
外国民族医学 | 31篇 |
外科学 | 36419篇 |
综合类 | 51075篇 |
现状与发展 | 12篇 |
一般理论 | 29篇 |
预防医学 | 36313篇 |
眼科学 | 5280篇 |
药学 | 31667篇 |
382篇 | |
中国医学 | 30873篇 |
肿瘤学 | 13508篇 |
出版年
2023年 | 5480篇 |
2022年 | 9718篇 |
2021年 | 13302篇 |
2020年 | 12374篇 |
2019年 | 18145篇 |
2018年 | 15856篇 |
2017年 | 12770篇 |
2016年 | 10340篇 |
2015年 | 9646篇 |
2014年 | 19910篇 |
2013年 | 21496篇 |
2012年 | 18400篇 |
2011年 | 19889篇 |
2010年 | 15994篇 |
2009年 | 14675篇 |
2008年 | 14321篇 |
2007年 | 14793篇 |
2006年 | 12912篇 |
2005年 | 11231篇 |
2004年 | 9153篇 |
2003年 | 8032篇 |
2002年 | 6315篇 |
2001年 | 5667篇 |
2000年 | 4694篇 |
1999年 | 4071篇 |
1998年 | 3319篇 |
1997年 | 3177篇 |
1996年 | 2742篇 |
1995年 | 2689篇 |
1994年 | 2548篇 |
1993年 | 2028篇 |
1992年 | 2067篇 |
1991年 | 1758篇 |
1990年 | 1582篇 |
1989年 | 1405篇 |
1988年 | 1334篇 |
1987年 | 1136篇 |
1985年 | 3804篇 |
1984年 | 4817篇 |
1983年 | 3361篇 |
1982年 | 3827篇 |
1981年 | 3564篇 |
1980年 | 3174篇 |
1979年 | 2916篇 |
1978年 | 2542篇 |
1977年 | 1914篇 |
1976年 | 2156篇 |
1975年 | 1632篇 |
1974年 | 1434篇 |
1973年 | 1278篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
MASASHI YOSHIDA GO WAKABAYASHI HIDEKI ISHIKAWA YOSHIHIDE OTANI MOTOHIDE SHIMAZU TETSURO KUBOTA KOICHIRO KUMAI IWAO KUROSE SOICHIRO MIURA HIROMASA ISHII MASAKI KITAJIMA 《Journal of gastroenterology and hepatology》1998,13(1):104-108
The effects of camostat mesilate, a synthetic serine protease inhibitor on gastric microcirculation and active oxygen species generated by leucocytes from the gastric and jugular veins in the early period after thermal injury were assessed. Male Wistar rats were anaesthetized and a 30% full skin-thickness dorsal burn was inflicted. Camostat mesilate (100 mg/kg) was dissolved in distilled water and administered orally to rats 40 min before thermal injury (the camostat group). The control animals (the vehicle group) were administered distilled water orally. Rolling leucocytes as well as Monastral blue B deposits in venules were observed using in vivo microscopy. Active oxygen species were measured by chemiluminescence. Camostat mesilate decreased the total length of gastric erosion, venular deposits of Monastral blue B, and rolling of leucocytes in venules, and relatively increased luminol-dependent chemiluminescence activity generated by zymosan-stimulated leucocytes 15 min after thermal injury. These results suggest that serine proteases are involved in the formation of gastric erosions and gastric microcirculatory disturbance in the early period after thermal injury. 相似文献
992.
成人特发性乳糖酶缺乏症的发生率极高,这些人进食牛奶后会出现胃肠胀气、腹痛、腹泄等对牛奶不耐受的消化不良症状。为解决这一问题,自1989年起,国内外不少学者是主张有产替代疗法,即将人工培养制备纯化的乳糖酶直接加入牛奶中以水解其中的乳糖来弥补成人乳糖酶的缺乏。 相似文献
993.
We have established a rat model that reflects the course of development of alcohol and opiate addiction. The present study
with d-amphetamine aimed to define general principles in the development of an addiction. Male rats had a continuous free choice
between d-amphetamine solutions (100, 200 and 400 mg/l) and water for 47 weeks. An initial intake of high doses of d-amphetamine during the first weeks of drug choice was followed by an individually stable pattern of drug consumption of moderate
drug doses. During this period of controlled consumption (from week 10 to week 40), the voluntary intake of d-amphetamine depended on individual factors (dominant rats: 0.37 ± 0.02 mg/kg per day, subordinate rats: 0.57 ± 0.05 mg/kg
per day) and environmental variables (group housing: 0.21 ± 0.02 mg/kg per day, single housing: 0.41 ± 0.03 mg/kg per day).
Beginning with week 41, voluntary d-amphetamine consumption progressively increased (1.9 ± 0.2 mg/kg per day in week 47), although the experimental conditions
remained unchanged. Drug intake during a retest (free choice as before) after 6 months of drug deprivation revealed that the
rats had persistently lost their control over drug intake and were no longer able to adjust drug taking to internal and external
conditions. These addicted rats took very high drug doses, even when all d-amphetamine solutions but not water were adulterated with bitter tasting quinine (6.6 ± 0.6 mg/kg per day; age-matched controls:
0.37 ± 0.04 mg/kg per day). Forced intake of d-amphetamine for 47 weeks (7.1 ± 0.3 mg/kg per day) via the drinking fluid caused physical dependence (hyperreactivity during
withdrawal) but did not lead to drug addiction (voluntary intake in the retest with adulteration: 0.42 ± 0.04 mg/kg per day).
Both the temporal development and the prerequisites of psychostimulant addiction were in principle the same as for alcohol
and opiates.
Received: 3 April 1998/Final version: 26 August 1998 相似文献
994.
Isolated noncompaction of the ventricular myocardium 总被引:6,自引:0,他引:6
Isolated noncompaction of the ventricular myocardium is a recently described anomaly. We report the first case of this anomaly
presenting as a restrictive cardiomyopathy, and the first association of this entity with endocardial fibrosis. 相似文献
995.
Toshio Mizutani Ken-ichi Nakamura Mutsuo Enomoto Masuhiro Sakata Shigeo Yamada 《Neuropathology》1998,18(1):80-90
A neuropathological study on 1540 consecutive autopsy brains ranging from 60 to 107 years of age revealed the following points. (1) Of the of the demented cases of the plaque-predominant type, 93% were complicated with multiple tiny cortical infarcts. They showed a tendency for dementia to develop before or after the appearance or worsening of a systemic disorder such as cardiovascular disease, respiratory infection and cancer. However, there was no case showing Alzheimer-type dementia (ATD). (2) The plaque-predominant type might be an extreme condition of brain aging in terms of senile plaques (SP). It is likely that although the pathological appearance of SP alone is not responsible for dementia, its coexistence with multiple cortical infarcts could be the cause of dementia. Therefore, this type should be distinguished from ATD. (3) Primary hippocampal degeneration could also be an extreme condition of brain aging in terms of neurofibrillary tangles. This condition was different pathologically from the hippocampal lesion in ATD. (4) Several characteristics of old-old and oldest-old patients were clarified. 相似文献
996.
The assessment of economic and quality-of-life outcomes of health care interventions is moving into a new era, with such assessments increasingly being made within the context of controlled clinical trials. Traditionally the measurement of many variables in economic evaluations, particularly costs, has been deterministic. In the context of clinical trials the measurement of variables is stochastic, with the standard principles of statistical inference being applied to analyse differences between treatments in terms of effectiveness. Economists participating in clinical research are therefore being called upon to specify the sample size for the economic component of the evaluation and to undertake statistical tests for differences in cost or cost-effectiveness. This paper discusses the current methodological issues surrounding stochastic measurement in clinical trials, discusses the additional issues raised by the assessment of economic and quality-of-life outcomes and specifies the challenges facing economists if they are to answer the questions now being posed about economic analysis by statisticians and clinical researchers. It is concluded that application of the standard principles of statistical inference to economic data is not straightforward and will require value judgements to be made about statistical significance and economic importance, which may differ from those already made in purely clinical studies. 相似文献
997.
Stimulation of the nasal mucosa produces a number of respiratory reflexes the afferent limb of which is provided by the ethmoidal nerve, a branch of the trigeminal nerve. In the cat this nerve terminates within the trigeminal nucleus. It has no direct projection to brainstem respiratory centres. This study examines the response of respiratory-related neurones in the nucleus of the solitary tract (NTS) to ethmoidal stimulation. It demonstrates that these neurones show both excitatory and inhibitory responses to ethmoidal stimulation. Thus, the NTS appears to be involved in respiratory reflexes initiated by stimulation of the nasal mucosa. 相似文献
998.
999.
Hiroshi Shimada Masao Nanko Shoichi Fujii Hidenobu Masui Shinji Togo Hideyuki Ike Akira Nakano Shigeo Ohki 《Journal of Hepato-Biliary-Pancreatic Surgery》1995,2(2):116-121
Hepatic micrometastases of the parenchyma adjacent to a macroscopic lesion were detected in 17 of 31 resected liver metastases.
Fifty-nine micrometastatic lesions were detected in total; 26 lesions were situated in the portal vein (PV), 22 in the central
vein (CV), 5 in the bile duct (BD), and 6 in the sinusoid (SS). A histological study confirmed the direct invasion of the
macrometastatic cancer cells into the adjacent PV, CV, BD, and SS. According to the tumor doubling time, the mean diameter
of the macrometastases in 19 remnant livers was calculated to have been 0.57±0.87 cm at the time of the primary resection.
The calculated diameter of 3 of these 19 macrometastases was found to be less than 0.01 cm, the minimum implantable size,
indicating that the cancer recurrence in these specimens may have developed from macroscopic metastatic lesions as a satellite,
and not from the primary tumor. In 13 patients who received doses of 5250 mg or more of 5 fluorouracil (FU) via the hepatic
artery, the cumulative disease-free rate 2 years postoperatively was 100%; this value was 47.6% in 11 patients who received
less than 5250 mg of 5 FU via the hepatic artery, and 0% in 39 patients who received no chemotherapy (P<0.005). These results suggest that anatomical hepatic resection for satellite lesions, combined with prophylactic hepatic
arterial chemotherapy for micrometastases, decreases the recurrence rate of hepatic metastases in the remnant liver. 相似文献
1000.
E. V. Grishina V. P. Shchipkov A. P. Pekhov 《Bulletin of experimental biology and medicine》1995,120(6):1233-1235
The inhibition of conjugative transfer of derepressed plasmids was appreciably increased in polyplasmid complexes ofEscherichia coli K-12 cells containing two repressed conjugative plasmids with the finV system of genetic transfer regulation, in comparison
with the individual effects of each of the two plasmids. Combination of two plasmids with the finU system or of plasmids with
the finU and finV systems did not result in such an increase of inhibitory activity.
Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N
o
12, pp. 619–622, December, 1995
Presented by T. T. Berezov, Member of the Russian Academy of Medical Sciences 相似文献