全文获取类型
收费全文 | 292968篇 |
免费 | 7007篇 |
国内免费 | 146篇 |
专业分类
耳鼻咽喉 | 2928篇 |
儿科学 | 11844篇 |
妇产科学 | 6985篇 |
基础医学 | 32750篇 |
口腔科学 | 4435篇 |
临床医学 | 20890篇 |
内科学 | 52962篇 |
皮肤病学 | 4064篇 |
神经病学 | 25520篇 |
特种医学 | 13969篇 |
外国民族医学 | 32篇 |
外科学 | 47934篇 |
综合类 | 3916篇 |
一般理论 | 42篇 |
预防医学 | 24214篇 |
眼科学 | 6133篇 |
药学 | 17724篇 |
中国医学 | 957篇 |
肿瘤学 | 22822篇 |
出版年
2018年 | 22817篇 |
2017年 | 18139篇 |
2016年 | 20620篇 |
2015年 | 2179篇 |
2014年 | 2476篇 |
2013年 | 3274篇 |
2012年 | 10185篇 |
2011年 | 24295篇 |
2010年 | 20817篇 |
2009年 | 13482篇 |
2008年 | 22835篇 |
2007年 | 25218篇 |
2006年 | 4315篇 |
2005年 | 6033篇 |
2004年 | 7141篇 |
2003年 | 7977篇 |
2002年 | 6081篇 |
2001年 | 7303篇 |
2000年 | 7370篇 |
1999年 | 6027篇 |
1998年 | 1842篇 |
1997年 | 1765篇 |
1996年 | 1425篇 |
1995年 | 1305篇 |
1994年 | 1187篇 |
1993年 | 1183篇 |
1992年 | 3801篇 |
1991年 | 3662篇 |
1990年 | 3694篇 |
1989年 | 3425篇 |
1988年 | 3038篇 |
1987年 | 2935篇 |
1986年 | 2826篇 |
1985年 | 2650篇 |
1984年 | 1964篇 |
1983年 | 1618篇 |
1982年 | 951篇 |
1981年 | 917篇 |
1980年 | 805篇 |
1979年 | 1826篇 |
1978年 | 1359篇 |
1977年 | 1119篇 |
1976年 | 945篇 |
1975年 | 1186篇 |
1974年 | 1233篇 |
1973年 | 1201篇 |
1972年 | 1042篇 |
1971年 | 976篇 |
1970年 | 901篇 |
1969年 | 808篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
This study investigates whether tissue recoil or patient intrinsic factors influence the final position of the nipple areola
complex (NAC) after reduction mammoplasty.
The age, pre-operative ptosis, BMI and weight of the tissue resected were recorded as patient intrinsic factors in 37 patients
undergoing reduction mammoplasty. The “spring-back” value was defined as the distance from the sternal notch to a nipple landmark
on the breast meridian with the patient sitting up, minus the same measurement repeated with the patient recumbent to eliminate
the pull of gravity on the breast. Spring back was measured pre-operatively for the nipple and nipple mark then post-operative
for the nipple. The difference in centimeters between the final post-operative distance from the sternal notch to the nipple
and the level intended by the pre-operative nipple mark was termed the “judgment error.” The final position of the post-operative
nipple and the judgment error was compared to the spring-back values and patient intrinsic factors.
Pre-operative ptosis was statistically related to increasing patient BMI and mass of tissue resected per breast. Pre-operative
spring-back values for the nipple increased with increasing ptosis, BMI and decreasing age. Spring-back values were greater
in the lower pole of the breast than in the upper pole. The final position of the nipple was higher than the pre-operative
mark in 65% of cases, lower in 8% and as marked in 27% of cases. The post-operative NAC was, on average, 0.6 cm higher than
planned pre-operatively. The post-operative distance from the sternal notch to the nipple increased with increasing pre-operative
ptosis, mass of breast tissue resected per breast and all three spring-back values. The difference between the level of the
pre-operative mark and the final nipple position showed a weak correlation with post-operative spring-back values.
The parameters of ptosis, BMI, weight of tissue resected per breast and pre-operative nipple spring back reflect body habitus
and breast size. Spring-back values vary between the upper and lower pole of the breast. The final NAC position was higher
than that intended at pre-operative marking in the majority of cases. The surgeon instinctively marks the nipple lower in
patients with greater pre-operative ptosis and in whom a larger resection is anticipated. Judgment error did not relate to
intrinsic factors nor to pre-operative spring-back values; hence, these parameters cannot be applied as predictive tools for
more accurate pre-operative marking of the nipple position. This study suggests that the pre-operative nipple mark should
be placed, with the patient sitting up, at least 23 cm from the sternal notch and 0.6 cm lower than the final position estimated
using the inframammary crease as a landmark.
An invited commentary on this paper is available at . 相似文献
92.
93.
Jamshid Shirani Jagat Narula William C. Eckelman Navneet Narula Vasken Dilsizian 《Journal of nuclear cardiology》2007,14(1):100-110
Conclusions Noninvasive imaging of neurohumoral upregulation in remodeled myocardium suggests that an imaging strategy can be developed
for predicting the rate of remodeling and likelihood of HF development. This should allow a more judicious use of neurohumoral
antagonists especially in subjects who do not have manifest HF.74 In others specific targeted imaging may allow timely selection of individualized treatment strategies and ensure optimization
of therapeutic intervention. Similar to ACE and AII receptors, multiple other targets in the hormonal cascades can identify
the likelihood of adverse and favorable remodeling.74 相似文献
94.
BACKGROUND AND AIMS: Liver surgery is developing with new techniques and treatment modalities. The aim of this study is to describe liver surgery over a long period of time in a country with a public health care system. PATIENTS AND METHOD: A register study including adult patients admitted for liver resection in Sweden (population 8.8 million) selected from the Inpatient Register 1987-99. Additional data were collected from the Swedish Cancer Register and the Cause of Death Register. Analyses of the patients, indications, mortality and causes of death are presented. RESULTS: 2,405 operations were performed (21 per million per year). The most frequent indication was colorectal metastases (27%). The 5-year survival after an operation for primary liver cancer and colorectal liver metastases was 27% and 26%, respectively. CONCLUSIONS: Few patients were admitted for liver operations compared to expected figures. The survival rates are in conformity with those previously published. With an increasing awareness of the relatively favourable prognosis and the introduction of new methods, the volume of liver operations will probably increase in Sweden. 相似文献
95.
Stress-induced changes in cholecystokinin and substance P concentrations in discrete regions of the rat hypothalamus 总被引:4,自引:0,他引:4
The effects of acute stress exposure upon cholecystokinin (CCK) and substance P (SP) concentrations in discrete hypothalamic regions of the adult male rat brain were studied. Animals were exposed to foot shock stress for periods of 2, 4, 10, 30 or 60 min duration; immediately afterwards they were decapitated; brains were frozen and subsequently microdissected. CCK and SP concentrations were assayed by a specific RIA, as were serum levels of ACTH, corticosterone, PRL, GH, LH and testosterone. Stress had no effect upon SP concentrations in the anterior or posterior parts of the arcuate nucleus (ARC), but led to elevated CCK levels in the posterior ARC following 60 min of exposure. In both the ventromedial and dorsomedial hypothalamic areas, stress induced depletions of both neuropeptides. In the anterior (but not the posterior) portions of the lateral hypothalamic area, CCK and SP concentrations were reduced by stress exposure. These studies demonstrate that discrete hypothalamic CCK and SP neuronal systems are responsive to stress. This suggests that endogenous hypothalamic CCK and SP participate, along with other neurotransmitters/neuromodulators, in the integrated hypothalamic stress response, and mediate stress-neuroendocrine interactions. 相似文献
96.
Activating effect of substance P on nerve tissue in culture 总被引:1,自引:0,他引:1
The effect of substance P on organotypic culture of rat sympathetic ganglia and spinal cord was studied. Substance P was able to stimulate the fibre outgrowth from explant, to increase the numbers of glial and fibroblasttypic cells in ganglia growth zone. The effect was observed in the range from 10(-5) to 10(-12) M (for sympathetic ganglia) and from 10(-5) to 10(-14) M (for spinal cord culture). It is suggested that substance P can be used as a nonspecific growth factor for peripheral and central nervous tissue. 相似文献
97.
98.
U Jonsson 《Social science & medicine (1982)》1986,22(7):745-753
At independence in 1961, Tanzania inherited a classic economic structure from Britain. The most immediate aims of the new government included replacing the colonial administration with trained nationals, radical change of the development philosophy and strategies and development of self-reliance in all development sectors. The Arusha Declaration of 1967 was the turning point in Tanzania and achievements in all the sectors can be measured against targets established soon after. This paper examines development in the health sector within the wider national framework. 相似文献
99.
100.
Renal vascular reactivity in jaundice 总被引:1,自引:0,他引:1
Obstructive jaundice is associated with a predisposition to hypotension and acute renal failure that may be related to changes in renovascular responsiveness, particularly to norepinephrine (NE). This study was undertaken to investigate changes in vascular response to NE and to determine how these changes are related to prostaglandins. Kidneys from bile duct-ligated (BDL) rabbits (n = 5) were perfused with Krebs' solution at 7.65 ml/min, and the response to varying boluses of NE (0.78 to 6.24 micrograms) was measured as changes in perfusion pressure. When compared with sham-operated control kidneys (n = 8), a significantly blunted response was seen at all doses tested. The NE response was further assessed by measuring force development in mounted segments of main renal arteries (MRAs) (n = 8) and interlobar arteries (ILAs) (n = 6) from BDL rabbits and sham-operated controls (MRA, n = 8; ILA, n = 6). The dose-response curves were significantly depressed in both MRAs and ILAs from BDL animals. In addition, MRAs from sham-operated control animals exhibited decreased response to NE after incubation for 1 hour in jaundiced serum. This attenuated response of MRAs to NE was prevented when indomethacin (5 mg/kg) was given to BDL rabbits before death (n = 9) or when 10(-6)mol/L of indomethacin was added to jaundiced serum during incubation (n = 6). These results indicate that obstructive jaundice induces a decreased vascular contractile response in rabbits to NE and that this effect is mediated by prostaglandins. 相似文献