全文获取类型
收费全文 | 809979篇 |
免费 | 54064篇 |
国内免费 | 1434篇 |
专业分类
耳鼻咽喉 | 10795篇 |
儿科学 | 27898篇 |
妇产科学 | 21162篇 |
基础医学 | 124635篇 |
口腔科学 | 22491篇 |
临床医学 | 71261篇 |
内科学 | 154150篇 |
皮肤病学 | 19154篇 |
神经病学 | 57632篇 |
特种医学 | 30273篇 |
外国民族医学 | 108篇 |
外科学 | 121679篇 |
综合类 | 16174篇 |
现状与发展 | 2篇 |
一般理论 | 182篇 |
预防医学 | 56609篇 |
眼科学 | 19400篇 |
药学 | 61204篇 |
3篇 | |
中国医学 | 2639篇 |
肿瘤学 | 48026篇 |
出版年
2018年 | 8609篇 |
2017年 | 6756篇 |
2016年 | 7746篇 |
2015年 | 8601篇 |
2014年 | 11651篇 |
2013年 | 17430篇 |
2012年 | 23191篇 |
2011年 | 24194篇 |
2010年 | 14464篇 |
2009年 | 13613篇 |
2008年 | 22829篇 |
2007年 | 24552篇 |
2006年 | 25072篇 |
2005年 | 23763篇 |
2004年 | 23284篇 |
2003年 | 22114篇 |
2002年 | 21605篇 |
2001年 | 42503篇 |
2000年 | 43012篇 |
1999年 | 35578篇 |
1998年 | 9355篇 |
1997年 | 8084篇 |
1996年 | 8180篇 |
1995年 | 7724篇 |
1994年 | 7066篇 |
1993年 | 6602篇 |
1992年 | 26343篇 |
1991年 | 26153篇 |
1990年 | 25508篇 |
1989年 | 25103篇 |
1988年 | 22747篇 |
1987年 | 22043篇 |
1986年 | 21010篇 |
1985年 | 19730篇 |
1984年 | 14482篇 |
1983年 | 12212篇 |
1982年 | 6797篇 |
1981年 | 6107篇 |
1979年 | 13205篇 |
1978年 | 9386篇 |
1977年 | 7870篇 |
1976年 | 7457篇 |
1975年 | 8366篇 |
1974年 | 9600篇 |
1973年 | 9265篇 |
1972年 | 8625篇 |
1971年 | 8032篇 |
1970年 | 7699篇 |
1969年 | 7055篇 |
1968年 | 6489篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A. I. Fabra De Peretti G. B. Mori De Moro N. E. Ghittoni A. M. Evangelista De Duffard R. O. Duffard 《Environmental toxicology》1987,2(2):217-228
The effects of 2,4-Dichlorophenoxyacetic acid on the growth rate, chemical composition, 14C-2,4-dichlorophenoxyacetic acid and 45Ca2+ uptake by Rhizobium sp. M 4 able to nodulate Arachis hypogaea were determined. Cellular growth was diminished by the presence of 10?3 M 2,4-dichlorophenoxyacetic acid in the medium. Alterations in cellular chemical composition, in 14C-2,4-dichlorophenoxyacetic acid and in 45Ca2+ uptake were found. 相似文献
992.
993.
T Ito S Tanaka K Ban N Sakai H Oshita T Oiwa A Kanno T Kashizuka 《Gan to kagaku ryoho. Cancer & chemotherapy》1987,14(10):2917-2923
During the past 4 years, the performances of various tumor markers such as CA15-3, CEA, ferritin, beta 2-microglobulin and TPA have been evaluated in 78 cases of mammary cancer. The results were categorised according to differences in stages, difference in values from patients with recurrent tumors, the incidence of abnormal values and differences in values before and after surgery. When the incidence of values higher than the cutoff value was determined for each of stage I, II and III + IV, the rates for CEA were 14.3%, 4.9% and 27.8%, respectively, whereas those for TPA were 25.0%, 22.2% and 26.7%, respectively. In addition, for CA15-3, the incidences were 0% in stage I, 5.0% in stage II and 57.1% for combined stages III + IV. The average values for patients with recurrent tumors were 3.2 ng/ml CEA, 194.5 ng/ml ferritin, 316.2 U/l TPA and 81.3 U/ml CA15-3. The rates of abnormal values were 40.0% for CEA, 40.0% for ferritin, 85.7% for TPA and 63.6% for CA15-3. Differences in the values after surgical removal of the tumor were observed with these tumor markers: the CEA value was reduced from 1.6 +/- 1.4 to 1.1 +/- 0.5 (p less than 0.01) and the CA15-3 value from 12.2 +/- 8.4 to 9.3 +/- 4.1 (p less than 0.05), respectively, whereas that for ferritin was conversely increased from 48.9 +/- 48.0 to 74.0 +/- 70.0 (p less than 0.01). However, the values for TPA, despite showing a tendency to decrease, did not show any statistically significant alteration. The fluctuations of these marker levels in patients with recurrent tumors reflects the progress of the disease, with a sudden elevation in values indicating imminent death. The diagnostic significance of these markers is not high, but they are considered to be useful in detecting the progress or condition of a recurrent tumor. 相似文献
994.
995.
A Golik D Modai J Weissgarten N Cohen Z Averbukh E Sigler R Zaidenstein U Shaked 《Clinical pharmacology and therapeutics》1987,42(1):42-44
Serum zinc levels and urinary zinc excretion were compared in 15 patients with essential hypertension taking chronically a combination of hydrochlorothiazide and amiloride as monotherapy, eight patients maintained with hydrochlorothiazide alone, and eight control subjects. Serum zinc values were statistically comparable in all three groups. However, urinary zinc excretion was abnormally elevated in the two patient groups. In the dosage used, amiloride did not have a zinc-sparing effect. 相似文献
996.
997.
Demonstration of malignant cells in blood specimens collected during transurethral resection of the prostate (TURP) has implicated TURP in the dissemination of prostatic cancer. Of 153 patients who underwent radiation therapy for prostate cancer between January 1977 and June 1990 and were retrospectively analyzed, 93 were evaluable. Fifty-nine patients required TURP before radiation therapy for prostatic obstruction (BPH and/or cancer); the remaining 34 patients underwent radiation therapy after fine-needle aspiration biopsy. No statistically significant difference in failure rate could be detected between these groups, with a failure rate of 47% (28 of 59 patients) at a median follow-up time of 49 months (range, 8 to 146 months) in the TURP group versus a failure rate of 47% (16 of 34 patients) at a median follow-up time of 50 months (range, 3 to 122 months) in the group who underwent biopsy only (Fisher's exact test, P = 0.23). Within the confines of this retrospective study, it appeared that TURP did not enhance the development of metastatic disease. 相似文献
998.
N Sadatoh H Hatabu M Takahashi K Imanaka A Sano 《Journal of computer assisted tomography》1987,11(4):742-744
To achieve prolonged breath-holding, oxygen was administered just before dynamic CT and high resolution lung CT. Oxygen administration has proved to be a supportive means to improve the quality of CT studies. 相似文献
999.
A Montanara R Pani R Pellegrini N S Polli S Soluri 《The British journal of radiology》1986,59(708):1171-1173
This paper describes research into measurement and reduction of the radiation dose to the lens during various examinations, namely skull and orbit, optic canal and optic strut, superior and inferior orbital fissure, localisation of foreign bodies in the eye, calcifications, orbital fractures, macrodacryography and orbital venography. Using rare-earth screens and high-sensitivity films, without an antiscattering grid, and with an added filtration of 0.5 mm Cu, it is possible to reduce the radiological risk during all investigations involving skull, orbit and eyeballs, while maintaining a good image quality. Particularly in those examinations with direct magnification (macrodacryography and venography, foreign bodies in the eye, orbital fractures), the dose to the lens is very low: less than 0.2 mGy/radiograph. 相似文献
1000.
Evaluation of a Bayesian method of amikacin dosing in intensive care unit patients with normal or impaired renal function 总被引:2,自引:0,他引:2
B Lacarelle C Granthil J C Manelli N Bruder G Francois J P Cano 《Therapeutic drug monitoring》1987,9(2):154-160
Our study was designed to determine the population pharmacokinetic parameters of amikacin in intensive care unit patients and to develop a Bayesian method allowing individual estimation of pharmacokinetic parameters. A two-stage method was used for estimating the population characteristics of the pharmacokinetic parameters. Calculations of optimum doses and dosing intervals were based on individual parameters. Our results indicate that the Bayesian method is capable of estimating the individual pharmacokinetic parameters with no significant bias and good precision. Individualization of amikacin dosage was assessed 70 times in 52 patients. To determine the predictive performance of the method, observed peak and trough levels were compared with predicted values by computing precision, bias, and correlation. The amikacin dosing method was unbiased and showed a high correlation coefficient (r = 0.962) between measured and predicted drug serum concentrations. No significant differences were found between the predicted and observed peak (17.3 +/- 3.5 and 17.3 +/- 3.8 micrograms/ml, respectively) and trough (2.86 +/- 0.93 and 3.08 +/- 1.41 micrograms/ml, respectively) amikacin serum concentrations. Among the 52 patients, wide variations were observed in the pharmacokinetic parameters (Vd = 0.21-0.50 L/kg; t 1/2 = 1.1-22 h) and the daily doses (2.8-42 mg/kg/day). 相似文献