全文获取类型
收费全文 | 148808篇 |
免费 | 13046篇 |
国内免费 | 9899篇 |
专业分类
耳鼻咽喉 | 1336篇 |
儿科学 | 1835篇 |
妇产科学 | 2498篇 |
基础医学 | 16822篇 |
口腔科学 | 2484篇 |
临床医学 | 19126篇 |
内科学 | 23218篇 |
皮肤病学 | 1670篇 |
神经病学 | 7867篇 |
特种医学 | 5096篇 |
外国民族医学 | 73篇 |
外科学 | 15271篇 |
综合类 | 24365篇 |
现状与发展 | 28篇 |
一般理论 | 6篇 |
预防医学 | 9953篇 |
眼科学 | 4024篇 |
药学 | 15472篇 |
147篇 | |
中国医学 | 7934篇 |
肿瘤学 | 12528篇 |
出版年
2024年 | 461篇 |
2023年 | 2179篇 |
2022年 | 5529篇 |
2021年 | 7044篇 |
2020年 | 5177篇 |
2019年 | 4817篇 |
2018年 | 4805篇 |
2017年 | 4461篇 |
2016年 | 4073篇 |
2015年 | 6238篇 |
2014年 | 7816篇 |
2013年 | 7448篇 |
2012年 | 10757篇 |
2011年 | 11654篇 |
2010年 | 7488篇 |
2009年 | 5908篇 |
2008年 | 7817篇 |
2007年 | 7832篇 |
2006年 | 7673篇 |
2005年 | 7518篇 |
2004年 | 5311篇 |
2003年 | 5142篇 |
2002年 | 4490篇 |
2001年 | 3975篇 |
2000年 | 3782篇 |
1999年 | 3852篇 |
1998年 | 2432篇 |
1997年 | 2351篇 |
1996年 | 1724篇 |
1995年 | 1596篇 |
1994年 | 1390篇 |
1993年 | 873篇 |
1992年 | 1295篇 |
1991年 | 1136篇 |
1990年 | 977篇 |
1989年 | 858篇 |
1988年 | 745篇 |
1987年 | 694篇 |
1986年 | 534篇 |
1985年 | 479篇 |
1984年 | 253篇 |
1983年 | 181篇 |
1982年 | 123篇 |
1981年 | 119篇 |
1980年 | 77篇 |
1979年 | 122篇 |
1978年 | 59篇 |
1976年 | 52篇 |
1975年 | 55篇 |
1974年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
81.
Li-Tzy Wu Sc.D Daniel J 《医疗保健器具》2007,(10):57-58
目的:这个研究是调查酒精治疗服务在大学青年(18到22岁)中的运用和迫切需要,根据教育程度大学青年可分为:全日制大学生、在职大学生和非大学学生(通常是在大学以下的最高级学校在读的学生),和非学生(N=11337)。青年人的细目分类在以前还没展现出来。 相似文献
82.
Fracture of the patella treated by open reduction and external compressive skeletal fixation 总被引:1,自引:0,他引:1
Open reduction combined with external compressive skeletal fixation was used to treat twenty-seven patients who had a separated fracture of the patella. Fixation was obtained by the use of two compressive clamps applied to stainless-steel pins that were inserted just proximal and distal to the proximal and distal poles of the patella. Range-of-motion exercises for the knee were begun at two weeks and the pins were removed at three to four weeks. All of the fractures healed. Twenty-four patients regained a range of motion that was equal to that of the opposite knee. There was no evidence of chronic osteomyelitis. Osteoarthritis was noted in one patient who refused excision of a portion of the patella. 相似文献
83.
84.
应用低严格度—单引物聚合酶链反应对问号钩体中国参考株的… 总被引:1,自引:0,他引:1
G1、G2引物是对问号钩体具有特异性引物。分别用G1或G2单引物对问号钩体中国参考株进行前4个低严格度循环的PCR扩增,扩增带谱显示赖型、犬型、致热型、秋季型、澳洲型、临海型、乌尔夫型、溶血型为一类,而爪哇型、拜伦型、波摩那型、七日热型、巴叶赞型塔拉索夫型、曼耗Ⅱ型是不与以上赖型等血清型本为一类,双曲钩体atoc型及伊利尼细丝体伊利尼型的扩增带谱与问号钩体截然不同。应用苯酚法提取的高纯度钩体DNA 相似文献
85.
The sequence of rat hypothalamic pro-thyrotropin releasing hormone, deduced by sequencing of cDNA, in addition to 5 TRH progenitor genitor sequences contains leader, trailer and 4 intervening sequences separated by paired basic amino acid sequences. We have developed radioimmunoassays to synthetic peptides corresponding to portions of these cryptic proTRH sequences and have used these assays to identify and partially characterize proTRH peptides, distinct from TRH, in extracts of rat brain. Two of these peptides correspond closely in size to one intervening sequence and the car☐y-terminal sequence of proTRH. Three other peptides correspond to the intact amino-terminal leader sequence and two peptides formed by a further cleavage of the leader sequence at an internal paired basic amino acid sequence. 相似文献
86.
Dr. Yen-Chun Lin MD Jiahn-Shing Lee MD Shiu-Chen Wu MD Ling-Yuh Kao MD Chia-Yun Li MD Ken-Kuo Lin MD 《Annals of Ophthalmology》2003,35(1):19-24
This study analyzed the feasibility of fitting keratoconus-affected corneas with nonkeratoconus rigid gas-permeable (RGP)
contact lenses. We retrospectively studied patients with a diagnosis of keratoconus in the past 10 years who were fitted successfully
with nonkeratoconus RGP lenses by the same physician. Results confirmed nonkeratoconus RGP lenses as the first-line correction
tool. Additionally, we found a simple equation to speed the choice of the base curves of the lenses.
The authors have stated that they do not have a significant financial interest or other relationship with any product manufacturer
or provider of services discussed in this article. 相似文献
87.
88.
Cell type-specific gene expression in the neuroendocrine system. A neuroendocrine-specific regulatory element in the promoter of chromogranin A, a ubiquitous secretory granule core protein. 总被引:5,自引:1,他引:4 下载免费PDF全文
H Wu D J Rozansky N J Webster D T O'Connor 《The Journal of clinical investigation》1994,94(1):118-129
89.
Islet amyloid polypeptide (IAPP) has been recently identified as the principal constituent of amyloid deposits in pancreatic islets of patients with type 2 (non-insulin-dependent) diabetes mellitus and causes insulin resistance in some target cells. In addition, glucose-induced insulin secretion is inhibited by IAPP. We studied the effect of IAPP on proinsulin biosynthesis in rat insulinoma (RINr) cells. Glucose at concentrations of 0, 15, 30, 60, 100, and 300 mg/dl stimulated proinsulin biosynthesis in a dose-responsive and and actino-mycin D-inhibitable manner after 6 h of incubation. At a glucose concentration of 300 mg/dl, IAPP decreased the mean responses of proinsulin biosynthesis to 61.2 and 29% at concentrations of 0.1 and 1 microM, respectively, compared with the IAPP-free control. In conclusion, IAPP inhibits glucose-induced proinsulin biosynthesis in RINr cells. IAPP might play an important role in the pathogenesis of type 2 diabetes mellitus. 相似文献
90.
Two pharmacologically and kinetically distinct transient potassium currents in cultured embryonic mouse hippocampal neurons. 总被引:12,自引:0,他引:12
Transient potassium currents in mammalian central neurons influence both the repolarization of single action potentials and the timing of repetitive action potential generation. How these currents are integrated into neuronal function will depend on their specific properties: channel availability at the resting potential, activation threshold, inactivation rate, and current density. We here report on the voltage-gated transient potassium currents in embryonic mouse hippocampal neurons dissected at embryonic days 15-16 and grown in dissociated cell culture for up to 3 d. Two transient potassium currents, A-current and D-current, were isolated based on steady state inactivation and sensitivity to 4-aminopyridine (4-AP) and dendrotoxin (DTx). A-current had an activation threshold of approximately -50 mV and was half-inactivated at approximately -81 mV. A-current relaxations at voltages between -40 and +40 mV could be fit by single exponential functions with time constants of 20-25 msec; these time constants showed little sensitivity to voltage. In contrast, D-current had an activation threshold of between -40 and -30 mV and was half-inactivated at approximately -22 mV. D-current inactivation was voltage dependent; time constants of fitted exponential functions ranged from approximately 7 sec at -40 mV to 200 msec at +40 mV. A slower component of inactivation was also evident. D-current was preferentially blocked by 4-AP (100 microM) and DTx (1 microM). Operationally, A- and D-currents could be cleanly separated based on conditioning pulse potential and 4-AP sensitivity. Total transient potassium current amplitude increased during the time that neurons were in culture (recordings were made between 2 hr after dissociation and 3 d in culture). When normalized for cell capacitance (an index of membrane area), A-current density (pA/pF) decreased and D-current density increased, even during a period between days 1 and 3 when total transient current density remained constant. This observation suggests that A- and D-currents may be reciprocally modulated. Since blockade of D-current (with 100 microM 4-AP) increased both action potential duration and repetitive firing in response to constant current stimulation, long-term modulation of the A-current:D-current ratio may affect the excitability of hippocampal neurons. 相似文献