全文获取类型
收费全文 | 10362篇 |
免费 | 1092篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 438篇 |
妇产科学 | 210篇 |
基础医学 | 1368篇 |
口腔科学 | 224篇 |
临床医学 | 1127篇 |
内科学 | 2184篇 |
皮肤病学 | 113篇 |
神经病学 | 778篇 |
特种医学 | 488篇 |
外国民族医学 | 5篇 |
外科学 | 1441篇 |
综合类 | 299篇 |
现状与发展 | 1篇 |
一般理论 | 15篇 |
预防医学 | 1144篇 |
眼科学 | 263篇 |
药学 | 870篇 |
中国医学 | 4篇 |
肿瘤学 | 459篇 |
出版年
2022年 | 60篇 |
2021年 | 148篇 |
2020年 | 101篇 |
2019年 | 163篇 |
2018年 | 205篇 |
2017年 | 176篇 |
2016年 | 185篇 |
2015年 | 214篇 |
2014年 | 298篇 |
2013年 | 410篇 |
2012年 | 499篇 |
2011年 | 510篇 |
2010年 | 310篇 |
2009年 | 310篇 |
2008年 | 471篇 |
2007年 | 531篇 |
2006年 | 486篇 |
2005年 | 486篇 |
2004年 | 473篇 |
2003年 | 387篇 |
2002年 | 394篇 |
2001年 | 292篇 |
2000年 | 288篇 |
1999年 | 240篇 |
1998年 | 201篇 |
1997年 | 203篇 |
1996年 | 193篇 |
1995年 | 126篇 |
1994年 | 146篇 |
1993年 | 111篇 |
1992年 | 186篇 |
1991年 | 185篇 |
1990年 | 164篇 |
1989年 | 165篇 |
1988年 | 146篇 |
1987年 | 158篇 |
1986年 | 130篇 |
1985年 | 140篇 |
1984年 | 102篇 |
1983年 | 100篇 |
1982年 | 98篇 |
1981年 | 76篇 |
1980年 | 80篇 |
1979年 | 121篇 |
1978年 | 76篇 |
1977年 | 77篇 |
1976年 | 63篇 |
1974年 | 64篇 |
1973年 | 63篇 |
1968年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Michele C. Hindi-Alexander Ph.D. Maria A. Zielezny Ph.D. Naris Montes R.N. M.S. Bonnie Bullough Ph.D. Elliott Middleton Jr. M.D. Dutzu H. Rosner M.D. William M. London Ed.M. 《The Journal of allergy and clinical immunology》1985,75(6):709-715
After literature reports linking fibrocystic breast disease (FBD) to methylxanthine ingestion, a pilot study was undertaken to investigate the possible contribution of theophylline to this effect. The major goal of this project was to measure the effect of theophylline therapy on FBD in asthmatic women. All women attending an allergy clinic or an obstetrics/gynecology clinic over a 9-month period were examined to clinically assess FBD and were asked to complete a detailed questionnaire covering health history, other risk factors, and drug and dietary methylxanthines. The sample included 62 asthmatic women, 66 allergic but not asthmatic women, and 72 nonallergic and nonasthmatic women. By use of the FBD clinical taxonomy with its 19-point scale going from 0 to 18 that was developed for this study, the three groups did not differ significantly in terms of mean severity of FBD. On analyzing the effect of each of the methylxanthines on FBD severity, there is clear evidence that total methylxanthines was a contributing factor in FBD severity with or without adjustment for relevant variables, such as age, menopause, pregnancies, and groups. Theophylline was significant only when adjustments were made for age, pregnancy, and menopause in contrast to caffeine that was only significant with no adjustments. 相似文献
132.
Time course of hypo-osmotic swellings of human spermatozoa: evidence of ordered transition between swelling subtypes 总被引:2,自引:1,他引:2
Hossain AM; Rizk B; Barik S; Huff C; Thorneycroft IH 《Human reproduction (Oxford, England)》1998,13(6):1578-1583
The hypo-osmotic swelling test (HOST or HOS test) usually takes into
consideration the total HOS response value with no emphasis either on the
value of the response subtypes or the response evaluation time. This study
investigated the time course of HOS responses and analysed their
physiological relevance. Raw semen spermatozoa and Percoll washed
spermatozoa were used in the experiment. The morphological changes in the
sperm tail were monitored by incubating the spermatozoa in the hypo-
osmotic solution for 16 different time periods. The HOS reactive
spermatozoa and the type of HOS reaction (swelling subtypes) of the samples
subjected to different duration of treatment were identified under a phase
contrast microscope. Also the fate of individual spermatozoa in a
hypo-osmotic environment were monitored for 30 min. In spermatozoa exposed
to a hypo-osmotic solution, the motility lasted usually less than 2 min and
motility characteristics were uniquely different from that of the
spermatozoa under iso-osmotic conditions. The HOS response development was
permanent but the motility loss due to hypo-osmotic shock was reversible up
to 1 min of incubation. There was an indication of ordered transition among
the HOS swelling subtypes apparently initiating with subtype b destined to
c, d, e, f and g. Further, the subtypes a and g showed gradual decrease and
increase, respectively, while subtype b showed abrupt initial increase and
then gradual decrease. Transition from b to g could be direct or via one or
more than one subtypes. Ultrastructure based analysis indicated that HOS
response subtypes are the apparent reflection of the differences in the
cytoskeletal assembly of the sperm tail and thus may be identifying
different physiological variants in the sperm population. These results
indicate that shorter incubation is essential to document the kinetics of
various HOS responses but the conventional HOS test misses these important
HOS features because of lengthy incubation. Since the time course of
ordered transition of HOS responses will vary more than the total HOS
response in semen of different aetiologies, the importance of HOS response
subtypes and response evaluation time should be taken into consideration
when applying HOS test.
相似文献
133.
Elliott KJ Cable NT Reilly T Sefton V Kingsland C Diver M 《Experimental physiology》2005,90(2):215-223
The purpose of this study was to investigate the effects of supra-physiological changes in ovarian hormone levels on maximum force production in two conditions, one physiological (pregnancy) and one pseudo-physiological (in vitro fertilization (IVF) treatment). Forty IVF patients were tested at four distinct stages of treatment and 35 women were tested during each trimester of pregnancy and following parturition. Maximum voluntary isometric force per unit cross-sectional area of the first dorsal interosseus muscle was measured. Plasma concentrations of total and bioavailable oestradiol and testosterone were measured, in addition to the total concentrations of progesterone and human chorionic gonadotropin. Despite significant changes in the concentrations of total progesterone, 17beta-oestradiol, bioavailable oestradiol and testosterone between phases, strength did not change significantly throughout IVF treatment (1.30+/-0.29, 1.16+/-0.38, 1.20+/-0.29 and 1.26+/-0.34 N mm-2, respectively, in the 4 phases of IVF treatment). Force production was significantly higher during the second trimester of pregnancy than following childbirth (1.33+/-0.20 N mm-2 at week 12 of pregnancy, 1.51+/-0.42 N mm-2 at week 20, 1.15+/-0.26 N mm-2 at week 36 and 0.94+/-0.31 N mm-2 at week 6 postnatal) but was not significantly correlated with any of the hormones measured. These data suggest that extreme changes in the concentrations of reproductive hormones do not affect the maximum force-generating capacity of young women. 相似文献
134.
The effect of ovarian steroids on epithelial ciliary beat frequency in the human Fallopian tube 总被引:3,自引:3,他引:3
Mahmood T; Saridogan E; Smutna S; Habib AM; Djahanbakhch O 《Human reproduction (Oxford, England)》1998,13(11):2991-2994
Using a method that detects variations in light intensity we have studied
the effect of ovarian steroids on human Fallopian tube epithelial ciliary
beat frequency in vitro. We have found that baseline ciliary beat frequency
averages between 5-6 Hz. Cilia from ampullary segments of the Fallopian
tube beat significantly faster (5.4 Hz+/-0.2) than those from fimbrial
segments (4.8 Hz+/-0.2). There was no significant difference in baseline
ciliary beat frequency at any other anatomical site in the Fallopian tube.
Incubation with progesterone (10 micromol/l) suppresses human Fallopian
tube epithelial ciliary beat frequency by 40-50%. This inhibition was
observed at similar magnitudes in all Fallopian tubes studied irrespective
of anatomical site. Progesterone-induced reductions in ciliary beat
frequency were concentration dependent and prevented by the progesterone
receptor antagonist mifepristone (RU486). Oestradiol alone (10 micromol/l)
had no effect on ciliary beat frequency at any anatomical site in the
Fallopian tube but did prevent the reduction in ciliary beat frequency seen
with progesterone when tissues were incubated with these two steroids
together.
相似文献
135.
136.
137.
138.
139.
A human homologue of Drosophila minibrain (MNB) is expressed in the neuronal regions affected in Down syndrome and maps to the critical region 总被引:4,自引:0,他引:4
140.