全文获取类型
收费全文 | 1548篇 |
免费 | 90篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 54篇 |
儿科学 | 41篇 |
妇产科学 | 84篇 |
基础医学 | 277篇 |
口腔科学 | 42篇 |
临床医学 | 147篇 |
内科学 | 249篇 |
皮肤病学 | 73篇 |
神经病学 | 129篇 |
特种医学 | 103篇 |
外科学 | 134篇 |
综合类 | 24篇 |
预防医学 | 52篇 |
眼科学 | 36篇 |
药学 | 88篇 |
中国医学 | 3篇 |
肿瘤学 | 112篇 |
出版年
2023年 | 11篇 |
2022年 | 28篇 |
2021年 | 43篇 |
2020年 | 28篇 |
2019年 | 42篇 |
2018年 | 42篇 |
2017年 | 24篇 |
2016年 | 48篇 |
2015年 | 36篇 |
2014年 | 51篇 |
2013年 | 64篇 |
2012年 | 112篇 |
2011年 | 115篇 |
2010年 | 71篇 |
2009年 | 50篇 |
2008年 | 76篇 |
2007年 | 74篇 |
2006年 | 88篇 |
2005年 | 85篇 |
2004年 | 66篇 |
2003年 | 61篇 |
2002年 | 64篇 |
2001年 | 39篇 |
2000年 | 27篇 |
1999年 | 22篇 |
1998年 | 21篇 |
1997年 | 13篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 25篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 19篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 3篇 |
排序方式: 共有1648条查询结果,搜索用时 2 毫秒
1.
2.
3.
Sports anemia. 总被引:13,自引:0,他引:13
E P Balaban 《Clinics in Sports Medicine》1992,11(2):313-325
It is apparent that exercise can influence erythropoiesis and red cell survival in a variety of fascinating ways. A number of mechanisms have been reviewed that could lead to mild changes in the Hb or red cell mean corpuscular volume. In addition, athletes may be at high-risk to develop decreased iron stores. Nevertheless, iron deficiency anemia is uncommon and the ritual of routine iron supplementation is not recommended. Clearly, most of the mechanisms discussed lead to only subtle changes in the overall red cell numbers and indices. Yet there is a small subset of athletes who will have red cell changes that can only be attributable to participation in sports. The diagnosis of sports anemia, however, remains one of exclusion. 相似文献
4.
The steady-state kinetics of the creatine kinase reaction in rabbit skeletal muscle in vivo was investigated using inversion and saturation magnetization transfer techniques. Both techniques determined the forward rate of this reaction (creatine phosphate ATP) as approximately 0.3 s-1. This corresponds to a flux of 10 mumol creatine phosphate/s/g muscle. The saturation transfer technique underestimated the reverse reaction by approximately 56%. This result is likely due to the participation of ATP in other interactions in skeletal muscle not involving creatine phosphate. 相似文献
5.
Shobha Narahari Abida Juwle Subhankar Basak Dhananjaya Saranath 《Infection, genetics and evolution》2009,9(4):643-645
Viral hepatitis represents a major global health problem with 170 million Hepatitis C Virus (HCV) carriers worldwide, and 12–13 million HCV carriers in India. HCV genotypes are of clinical significance in indicating drug responsiveness and prognosis of the patient. The HCV genotypes are of epidemiologic significance as well, as they are indicative of transmission route of infection and have not been extensively studied in the Indian context. In the current study, HCV genotyping was examined in 2118 patients from different geographic regions of India. HCV was detected by PCR amplification of 5′ UTR and core-envelope1 regions, followed by genotyping using nucleotide sequencing and analysis with NCBI tool (http://www.ncbi.nlm.nih.gov/projects/genotyping/formpage.cgi). HCV genotype distribution in the 2118 Indian patients demonstrated prevalence of HCV3 (3a/3b primarily) in 62% and HCV1 (1a/1b primarily) in 31% patients. The predominance of HCV3 was significant in northern (p = 0.01) and eastern (p = 0.008) regions of India. HCV types 2, 4, 5, and 6 were detected in 0.05–4.5% of the patient group. Thus, our studies demonstrate HCV genotype prevalence in the cohort group in different regions of India. 相似文献
6.
BACKGROUND: Middle ear pathology, either otitis media with effusion or
tubal dysfunction, is frequently seen in day-care centre children.
Recognition and early treatment of this condition is crucial to the
prevention of chronic otitis media, which is a major cause of hearing loss
in later life. OBJECTIVES: We aimed to reveal the incidence of silent
otitis media in day-care centre children and to determine the predisposing
factors, risk factors and the awareness of the parents of the middle ear
disease of their children. METHOD: Two hundred and thirteen children, aged
3-6 years, were screened in four daycare centres. A questionnaire was
prepared that would reveal the predisposing factors. Information was
gathered from both the parents and teachers. Children were examined by
otoscopy, pneumotoscopy, tympanometry and X-rays for sinus pathology.
RESULTS: Forty-three of 213 children had middle ear pathology; 39 of them
were confirmed by tympanometry; 56.1 % of children had some degree of sinus
pathology. We revealed that, although most of the children do not have the
risk factors, they develop middle ear pathology. Among the parents, 81.4%
of them were unaware of the condition. CONCLUSION: Early diagnosis of
middle ear pathologies is necessary for prevention of future complications.
In early stages the condition is silent. We emphasize the importance of the
primary care physician's role in diagnosing the early stages of middle ear
pathologies and recommend that teaching of otoscopic and pneumotoscopic
skills should be part of the training for family physicians.
相似文献
7.
Oocyte morphology does not affect fertilization rate, embryo quality and implantation rate after intracytoplasmic sperm injection 总被引:6,自引:10,他引:6
Balaban B; Urman B; Sertac A; Alatas C; Aksoy S; Mercan R 《Human reproduction (Oxford, England)》1998,13(12):3431-3433
In this study, we compared the fertilization rate and embryo quality after
intracytoplasmic sperm injection (ICSI) as they relate to oocyte
morphology. A total of 654 ICSI cycles yielding 5903 metaphase II oocytes
were observed. The oocytes retrieved in these cycles were divided into (i)
normal oocytes, (ii) oocytes with extracytoplasmic abnormalities (dark zona
pellucida and large perivitelline space), (iii) oocytes with cytoplasmic
abnormalities (dark cytoplasm, granular cytoplasm, and refractile body),
(iv) oocytes with shape abnormalities, and (v) oocytes with more than one
abnormality (double and triple abnormalities). Intracytoplasmic vacuoles
and aggregates of smooth endoplasmic reticulum were not recorded
separately. The fertilization rate and quality of morphologically graded
embryos did not differ between the groups. There were 77 cycles where all
transferred embryos were derived from abnormal oocytes, and 164 cycles
where all embryos were derived from normal oocytes. These cycles were
studied further. The two groups were comparable regarding mean female age,
duration of infertility, duration of ovarian stimulation, number of
ampoules of gonadotrophin injected, and number of oocytes retrieved. Two
clinical pregnancy rates (44.4 versus 42.1%) and implantation rates per
embryo (10.3 versus 13.2%) were similar. In conclusion, in couples
undergoing ICSI, abnormal oocyte morphology is not associated with a
decreased fertilization rate or unfavourable embryo quality. Furthermore,
embryos derived from abnormal oocytes yield similar clinical pregnancy and
implantation rates when transferred compared with embryos derived from
normal oocytes.
相似文献
8.
D-Aldosterone (5 ng/microliter/h) was infused for 6 days into the region of the subcommissural organ (SCO) of conscious, adult male Sprague-Dawley rats. Aldosterone increased urinary sodium loss and the sodium/potassium ratio. Although probably central in origin, these effects still occurred when cannulae were displaced up to 1 mm from the targeted SCO placement. Aldosterone decreased adrenal medullary cross-sectional area without affecting cell density. This effect was highly dependent on proper cannula placement and was not observed when the cannula tip was not in contact with the cerebrospinal fluid of the pineal recess over the rostral two-thirds of the SCO. We conclude that aldosterone increases sodium excretion by an action in the SCO and/or adjacent structures. We also postulate a negative trophic relationship between mineralocorticoids and the adrenal medulla mediated by the SCO. 相似文献
9.
S. D. Stocker B. C. Steinbacher Jr. C. D. Balaban B. J. Yates 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,116(2):270-282
A region of the caudal ventrolateral medullary reticular formation (CVLM) participates in baroreceptor, vestibulosympathetic,
and somatosympathetic reflexes; the adjacent retroambigual area is involved in generating respiratory-related activity and
is essential for control of the upper airway during vocalization. However, little is known about the connections of the CVLM
in the cat. In order to determine the locations of terminations of CVLM neurons, the anterograde tracers Phaseolus vulgaris leucoagglutinin and tetramethylrhodamine dextran amine were injected into this region. These injections produced a dense concentration
of labeled axons throughout the lateral medullary reticular formation (lateral tegmental field), including the retrofacial
nucleus and nucleus ambiguus, regions of the rostral ventrolateral medulla, the lateral and ventrolateral aspects of the hypoglossal
nucleus, nucleus intercalatus, and the facial nucleus. A smaller number of labeled axons were located in the medial, lateral,
and commissural subnuclei of nucleus tractus solitarius, the A5 region of the pontine reticular formation, the ventral and
medial portions of the spinal and motor trigeminal nuclei, locus coeruleus, and the parabrachial nucleus. We confirmed the
projection from the CVLM to both the rostral ventrolateral medulla and lateral tegmental field using retrograde tracing. Injections
of biotinylated dextran amine or Fluorogold into these regions resulted in retrogradely labeled cell bodies in the CVLM. However,
the neurons projecting to the lateral tegmental field were located mainly dorsal to those projecting to the rostral ventrolateral
medulla, suggesting that these neurons form two groups, possibly with different inputs. Injections of retrograde tracers into
the lateral tegmental field and rostral ventrolateral medulla also produced labeled cell bodies in other regions, including
the medial and inferior vestibular nuclei and nucleus solitarius. These data are consistent with the view that the CVLM of
the cat is a multifunctional area that regulates blood pressure, produces vocalization, affects the shape of the oral cavity,
and elicits contraction of particular facial muscles.
Received: 18 February 1997 / Accepted: 27 March 1997 相似文献
10.