全文获取类型
收费全文 | 273901篇 |
免费 | 23361篇 |
国内免费 | 16530篇 |
专业分类
耳鼻咽喉 | 2350篇 |
儿科学 | 3428篇 |
妇产科学 | 5345篇 |
基础医学 | 32193篇 |
口腔科学 | 4806篇 |
临床医学 | 34832篇 |
内科学 | 44802篇 |
皮肤病学 | 3088篇 |
神经病学 | 15454篇 |
特种医学 | 9587篇 |
外国民族医学 | 115篇 |
外科学 | 30112篇 |
综合类 | 39061篇 |
现状与发展 | 56篇 |
一般理论 | 48篇 |
预防医学 | 17002篇 |
眼科学 | 7474篇 |
药学 | 27460篇 |
175篇 | |
中国医学 | 12590篇 |
肿瘤学 | 23814篇 |
出版年
2024年 | 782篇 |
2023年 | 3903篇 |
2022年 | 9636篇 |
2021年 | 12697篇 |
2020年 | 9407篇 |
2019年 | 8485篇 |
2018年 | 9021篇 |
2017年 | 7918篇 |
2016年 | 7555篇 |
2015年 | 11450篇 |
2014年 | 14340篇 |
2013年 | 13301篇 |
2012年 | 19838篇 |
2011年 | 21635篇 |
2010年 | 13248篇 |
2009年 | 10609篇 |
2008年 | 14499篇 |
2007年 | 14561篇 |
2006年 | 14030篇 |
2005年 | 14161篇 |
2004年 | 9785篇 |
2003年 | 8751篇 |
2002年 | 7523篇 |
2001年 | 6760篇 |
2000年 | 7009篇 |
1999年 | 7342篇 |
1998年 | 4194篇 |
1997年 | 4263篇 |
1996年 | 3231篇 |
1995年 | 3009篇 |
1994年 | 2617篇 |
1993年 | 1757篇 |
1992年 | 2572篇 |
1991年 | 2280篇 |
1990年 | 1921篇 |
1989年 | 1677篇 |
1988年 | 1453篇 |
1987年 | 1360篇 |
1986年 | 1116篇 |
1985年 | 876篇 |
1984年 | 586篇 |
1983年 | 458篇 |
1982年 | 256篇 |
1981年 | 240篇 |
1980年 | 218篇 |
1979年 | 274篇 |
1978年 | 165篇 |
1977年 | 129篇 |
1976年 | 115篇 |
1974年 | 123篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
B. Shen MD Z. Younossi MD B. Dolmatch MD J. Newman MD M. Henderson MD J. Ong MD T. Gramlich MD M. Yamani MD 《The American journal of gastroenterology》2000,95(9):2607-2607
112.
In vivo 19F NMR at 4.7 T has shown that the biphasic elimination of the vapor anesthetic isoflurane from rat brain is ca 15% slower in old (23-24 months) animals compared with young (5-6 months) animals. The fast kinetic component has a t1/2 of ca 7-9 min and the slow event, 100-115 min. Gas chromatographic measurement of arterial blood elimination displays age attenuation to the same extent, although a monophasic kinetic process (6-7 min). The slow wash-out from brain is thought to involve elimination from intracranial fatty tissue as postulated by others in rabbit brain. Longitudinal relaxation time measurements show monoexponential recovery and essentially identical values for young (1.09 + 0.11 s) and old (1.04 +/- 0.09 s) animals. For dipalmitoylphosphatidylcholine vesicles the monoexponential recovery also suggests rapidly exchanging averaged homogeneous lipid environments for the anesthetic, but the longer T1s (2.75 +/- 0.25 s) imply less restricted mobility compared with brain. Single T2 values were obtained in vivo, indicating either a single compartment or rapid exchange between multiple environments. These measurements were inconsistent, undoubtedly as a result of B1 inhomogeneity. The age-attenuated elimination kinetics for isoflurane are consistent with poorer cardiopulmonary function, whereas the T1 data suggest similar environments for the anesthetic in young and old brain tissue. 相似文献
113.
114.
BACKGROUND AND PURPOSE: The Doppler waveform patterns of loss of diastolic flow, appearance of retrograde diastolic flow, or no detectable flow in the cerebral arteries suggest significantly abnormal cerebral blood flow (CBF). A retrospective study was performed to show that significantly abnormal CBF alone, without clinical criteria, is not necessarily specific to brain death in the young pediatric population. PATIENTS AND METHODS: Forty-seven pediatric patients, from newborn to 4 years of age, were found to have significantly abnormal CBF, including 7 patients with loss of diastolic flow, 28 with retrograde diastolic flow, and 23 with no detectable cerebral flow on serial Doppler sonographic examinations. Their clinical data and sonographic results were collected and analyzed. RESULTS: Forty-two patients died, a few of whom had only transient improvement of cerebral flow. All of the patients with no detectable cerebral flow expired. Five patients survived with or without sequelae. Their underlying conditions that caused increased intracranial pressure were treated by medical and/or surgical intervention, and diastolic reversal of CBF corrected within 1 day in all 5. CONCLUSIONS: Although no detectable flow is a lethal sign, pediatric patients with loss or reversal of diastolic flow may survive with prompt and effective treatment. Using Doppler ultrasound to diagnose cerebral circulatory arrest should be done with caution in pediatric patients. 相似文献
115.
Three cases of proved peritoneal carcinomatosis were examined by magnetic resonance imaging (MRI). Air was used to distend the entire gastrointestinal tract via an antegrade method. The findings included seedings along the small intestine, transverse and sigmoid colon, stellate pattern in the mesentery, plaque-like and bulky tumor masses in the mesentery and greater omentum, and focal thickenings along the right subdiaphragmatic parietal peritoneum. Stenosis caused by tumor encasement at the duodenojejunal junction and ileocolic anastomosis were first detected by MRI and later confirmed by barium studies. Ascites was present in all cases. One case showed ascites located only along the left paracolic gutter. This report shows that MRI is also able to demonstrate peritoneal carcinomatosis by using air as a gastrointestinal contrast medium. 相似文献
116.
Gastric cancer is unusual during pregnancy. Also, because of the physiologic changes that occur with pregnancy, it is rare to see a worsening of peptic ulcers during pregnancy. A patient with an exacerbation of peptic ulcers presented with gastric carcinoma during pregnancy. 相似文献
117.
118.
T.-N. Wu Chen-Yang Shen Saou-Hsing Liou Guang-Yang Yang K.-N. Ko Show-Lin Chao Chao-Chun Hsu P.-Y. Chang 《International archives of occupational and environmental health》1997,69(6):386-391
To monitor the lead hazards in industries and to investigate the prevalence of elevated blood lead levels (BLLs) in lead-exposed
workers, a lead surveillance system (PRESS-BLLs) has been established and operated in Taiwan, Republic of China, since July
1993. A cohort of lead-exposed workers who received a periodic annual health examination at 55 accredited hospital laboratories
was constructed. A total of 9807 separate BLL measurements were reported to the system in 1994. The mean BLL was 15.8 μg/dl
in male workers and 11.6 μg/dl in female workers. The mean BLL of lead-exposed workers was significantly (P<0.05, z-test) higher than that of the general Taiwanese population (8.6 μg/dl for males and 6.7 μg/dl for females). In addition,
the BLLs of 983 (10.0%) workers exceeded the regulatory action level (40 μg/dl for males; 30 μg/dl for females). The workplaces
and homes of 57% of the workers with elevated BLLs were thoroughly investigated to determine the sources of lead contamination.
These actions identified the causes of elevated BLLs and set up strategies to reduce workers’ lead exposure. The establishment
of this occupational lead surveillance system represents a method for monitoring of lead hazards from occupational and environmental
settings to prevent lead poisoning. The information acquired from the system can help in the setting up of a priority of prevention
and the development of control measures. It is also useful for further monitoring of changes in the BLLs of the lead-exposed-worker
cohort. The Health Department of Taiwan can use this information to evaluate the effectiveness of current industrial hygiene
practice. Subjects with elevated BLLs have been medically treated and placed on long-term follow-up for sequelae.
Received: 2 September 1996/Accepted: 29 November 1996 相似文献
119.
Clinical observation of Qi deficiency syndrome in 72 patients with chronic obstructive pulmonary disease treated with Yiqi Mianyi Granule 下载免费PDF全文
Seventy-two patients of chronic obstructive pulmonary disease (COPD) of Qi deficiency syndrome with abnormal immune indices were treated with Yiqi Mianyi Granule (YQMYG) and the efficacy was compared with that of 30 cases treated with Zhenqi fuzheng Granule (ZQFZG) for control. Results showed that the markedly effective rate of symptomatic improvement of Qi deficiency in YQMYG group was 65.3%, the total effective rate 93.1%. 88.6% of the immune indices lower than normal were corrected and 43. 7% of them were normalized, while for indices that were higher than normal the rate were 78.2% and 52.9% respectively. These results suggested that YQMYG could improve symptom of Qi Deficiency markedly, strengthen cellular immunity and regulate immune dysfunction. Its therapeutic efficacy was obviously superior to ZQFZG (P<0.Q5). 相似文献
120.
A. Tibell A. Lindholm J. Sawe G. Chen B. Norrlind 《Basic & clinical pharmacology & toxicology》1995,76(2):115-121
Abstract: In the commercially available intravenous formulation of Cyclosporin A (Sandimmun®), polyoxyethylated castor oil (Cremophor®EL) is used as a solubilizing agent. We have recently reported that the acute nephrotoxic effect of this preparation was alleviated by replacing Cremophor®EL with a soybean oil-based fat emulsion in a rat model. To further explore the potential of fat emulsions as carriers for cyclosporin A, data on the in vivo pharmacokinetics and tissue distribution are required. In this study in pigs, the pharmacokinetics of soybean oil-cyclosporin A was compared to that of Sandimmun®. The two formulations seemed bioequivalent, as there were no significant differences in the systemic clearances, volumes of distribution or elimination half-lives. Moreover, the tissue distributions of soybean oil-cyclosporin A and Sandimmun® were compared in rats. These studies also included two additional lipid-based carriers: one based on iodized ester of poppy seed oil and the other on a liposomal preparation. The tissue distributions were found to be similar regardless of the carriers used. Fat emulsion carriers seem to offer possibilities for preparing better tolerated intravenous formulations of cyclosporin A while maintaining the same characteristics concerning pharmacokinetics and tissue distribution. 相似文献