全文获取类型
收费全文 | 4483篇 |
免费 | 343篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 104篇 |
儿科学 | 111篇 |
妇产科学 | 55篇 |
基础医学 | 726篇 |
口腔科学 | 76篇 |
临床医学 | 418篇 |
内科学 | 1046篇 |
皮肤病学 | 96篇 |
神经病学 | 215篇 |
特种医学 | 392篇 |
外科学 | 615篇 |
综合类 | 177篇 |
一般理论 | 4篇 |
预防医学 | 163篇 |
眼科学 | 48篇 |
药学 | 248篇 |
中国医学 | 14篇 |
肿瘤学 | 397篇 |
出版年
2023年 | 27篇 |
2022年 | 61篇 |
2021年 | 118篇 |
2020年 | 80篇 |
2019年 | 86篇 |
2018年 | 109篇 |
2017年 | 85篇 |
2016年 | 83篇 |
2015年 | 90篇 |
2014年 | 131篇 |
2013年 | 159篇 |
2012年 | 208篇 |
2011年 | 218篇 |
2010年 | 138篇 |
2009年 | 183篇 |
2008年 | 194篇 |
2007年 | 238篇 |
2006年 | 197篇 |
2005年 | 182篇 |
2004年 | 178篇 |
2003年 | 154篇 |
2002年 | 115篇 |
2001年 | 119篇 |
2000年 | 97篇 |
1999年 | 115篇 |
1998年 | 109篇 |
1997年 | 111篇 |
1996年 | 124篇 |
1995年 | 91篇 |
1994年 | 81篇 |
1993年 | 63篇 |
1992年 | 80篇 |
1991年 | 71篇 |
1990年 | 72篇 |
1989年 | 97篇 |
1988年 | 85篇 |
1987年 | 76篇 |
1986年 | 77篇 |
1985年 | 76篇 |
1984年 | 24篇 |
1983年 | 27篇 |
1982年 | 27篇 |
1981年 | 23篇 |
1980年 | 24篇 |
1979年 | 23篇 |
1978年 | 29篇 |
1977年 | 23篇 |
1976年 | 33篇 |
1975年 | 20篇 |
1974年 | 15篇 |
排序方式: 共有4905条查询结果,搜索用时 15 毫秒
61.
PURPOSE: The APC I1307K and E1317Q variants predispose to colorectal adenomas and carcinomas in Caucasians, but data are lacking in Asians. METHODS AND RESULTS: We sequenced the APC gene from codons 1261 to 1409 and found none of 147 Chinese, 20 Malay, and 11 Indian colorectal cancer patients in Singapore to carry the APC I1307K or E1317Q variants. CONCLUSION: These variants are rare in these Asian populations, and play little role in colorectal cancer causation in Chinese. 相似文献
62.
63.
Strain variation in glycosaminoglycan recognition influences cell-type-specific binding by lyme disease spirochetes
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lyme disease, a chronic multisystemic disorder that can affect the skin, heart, joints, and nervous system is caused by Borrelia burgdorferi sensu lato. Lyme disease spirochetes were previously shown to bind glycosaminoglycans (GAGs). In the current study, the GAG-binding properties of eight Lyme disease strains were determined. Binding by two high-passage HB19 derivatives to Vero cells could not be inhibited by enzymatic removal of GAGs or by the addition of exogenous GAG. The other six strains, which included a different high-passage HB19 derivative (HB19 clone 1), were shown to recognize both heparan sulfate and dermatan sulfate in cell-binding assays, but the relative efficiency of binding to these two GAGs varied among the strains. Strains N40, CA20-2A, and PBi bound predominantly to heparan sulfate, PBo bound both heparan sulfate and dermatan sulfate roughly equally, and VS461 and HB19 clone 1 recognized primarily dermatan sulfate. Cell binding by strain HB19 clone 1 was inhibited better by exogenous dermatan sulfate than by heparin, whereas heparin was the better inhibitor of binding by strain N40. The GAG-binding preference of a Lyme disease strain was reflected in its cell-type-specific binding. Strains that recognized predominantly heparan sulfate bound efficiently to both C6 glioma cells and EA-Hy926 cells, whereas strains that recognized predominantly dermatan sulfate bound well only to the glial cells. The effect of lyase treatment of these cells on bacterial binding was consistent with the model that cell-type-specific binding was a reflection of the GAG-binding preference. We conclude that the GAG-binding preference varies with the strain of Lyme disease spirochete and that this variation influences cell-type-specific binding in vitro. 相似文献
64.
Antiphospholipid antibodies and the outcome of pregnancy after the first in-vitro fertilization and embryo transfer cycle 总被引:1,自引:1,他引:1
Balasch J; Creus M; Fabregues F; Civico S; Reverter JC; Carmona F; Tassies D; Vanrell JA 《Human reproduction (Oxford, England)》1998,13(5):1180-1183
Increased antiphospholipid antibody prevalence has been demonstrated by a
number of recent studies in in-vitro fertilization (IVF) patients but the
potential effects of antiphospholipid antibodies on the different
components of the reproductive process and the consideration of whether to
test IVF patients for antiphospholipid antibodies are controversial. The
present study was undertaken to investigate the possible association
between the presence of circulating antiphospholipid antibodies (namely the
lupus anticoagulant and anticardiolipin antibodies), among a series of 21
consecutive IVF patients having a clinical spontaneous abortion after their
first embryo transfer. As a control group (n=42), the nearest IVF cycle
resulting in an ongoing pregnancy before and after each miscarried IVF
cycle (i.e. the closest cycles in temporal relationship to the index cycle)
was used. One patient (4.8%) in the study group and two women (4.8%) among
controls were seropositive for antiphospholipid antibodies. These low and
similar seropositivity rates found in the two groups studied lead us to
conclude that antiphospholipid antibodies testing in IVF patients should be
considered only in those women having repeated failures of
implantation/clinical abortion after embryo transfer but not in an
infertile general population reaching an IVF programme.
相似文献
65.
The effectiveness of a treatment protocol for male lower urinary tract symptoms in general practice: a practical randomised controlled trial
下载免费PDF全文
![点击此处可从《The British journal of general practice》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roelf JC Norg Kees van de Beek Piet JM Portegijs CP Onno van Schayck J Andr Knottnerus 《The British journal of general practice》2006,56(533):938-944
BACKGROUND: Randomised controlled trials have shown the efficacy of several treatment modalities for lower urinary tract symptoms (LUTS) in selected populations. The effectiveness in daily practice has hardly been investigated, especially in primary care and is dependent on choices between all possible treatment options and best investigated in a comprehensive study, including all treatment modalities (watchful waiting, alpha-blockers, 5-alpha-reductase inhibitors, and surgery). AIM: Assessment of the effectiveness of a comprehensive treatment protocol for LUTS in primary care. DESIGN OF STUDY: Randomised controlled trial. SETTING: Fourteen general practices in the Netherlands. METHOD: Intervention: treatment protocol based on a formalised expert opinion. Control condition: usual care. Study population: 208 subjects with moderate to severe LUTS (IPSS > or =8, median = 13). OUTCOME MEASURES: symptom severity (IPSS [International Prostate Symptom Score]), bother score (Dan-PSS [Danish Prostate Symptom Score]), and maximum urinary flow (Q(max)); incidence of acute urinary retention and urinary tract infections. RESULTS: In the intervention group markedly more subjects used an alpha-blocker at end of follow-up than in the usual care group (24% versus 6%). No significant differences were found between intervention and control group in IPSS, Q(max) or Dan-PSS. CONCLUSION: alpha-blockers and watchful waiting are the most frequent treatment modalities for LUTS in primary care. Our study showed no evidence that a protocol using well-defined indications for all possible treatment modalities based on a formalised expert opinion procedure has added value. Based on our results, we cannot recommend a broadening of the indication for alpha-blockers, which, however, seems to be the current trend. 相似文献
66.
67.
68.
Clarke GN; Bourne H; Hill P; Johnston WI; Speirs A; McBain JC; Baker HW 《Human reproduction (Oxford, England)》1997,12(4):722-726
Donor insemination (DI) using cryopreserved semen commenced at The Royal
Women's Hospital in 1976. Over the next 15 years we performed 5953
treatment cycles to achieve 816 pregnancies (13.7% per cycle) and 706 live
births. In-vitro fertilization (IVF) using donor spermatozoa commenced in
1986. Over the next 5 years we performed 303 treatment cycles for 185
couples. Including subsequent transfer of cryopreserved embryos, a total of
33% of couples achieved a successful pregnancy by IVF. Statistical analysis
indicated that, for DI pregnancies, the most important semen variable was
the percentage post-thaw motility, whilst for normal fertilization in IVF
it was the pre-freeze motility. These results may be explained by the
compensatory effects of post-thaw processing of spermatozoa for IVF, but
not for DI in our clinic.
相似文献
69.
70.