全文获取类型
收费全文 | 18870篇 |
免费 | 2017篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 153篇 |
儿科学 | 645篇 |
妇产科学 | 653篇 |
基础医学 | 2645篇 |
口腔科学 | 398篇 |
临床医学 | 2193篇 |
内科学 | 3834篇 |
皮肤病学 | 201篇 |
神经病学 | 1412篇 |
特种医学 | 612篇 |
外科学 | 2632篇 |
综合类 | 589篇 |
一般理论 | 43篇 |
预防医学 | 2288篇 |
眼科学 | 299篇 |
药学 | 1391篇 |
中国医学 | 16篇 |
肿瘤学 | 916篇 |
出版年
2021年 | 312篇 |
2020年 | 201篇 |
2019年 | 297篇 |
2018年 | 333篇 |
2017年 | 268篇 |
2016年 | 252篇 |
2015年 | 281篇 |
2014年 | 409篇 |
2013年 | 628篇 |
2012年 | 842篇 |
2011年 | 952篇 |
2010年 | 506篇 |
2009年 | 486篇 |
2008年 | 765篇 |
2007年 | 831篇 |
2006年 | 747篇 |
2005年 | 794篇 |
2004年 | 716篇 |
2003年 | 700篇 |
2002年 | 665篇 |
2001年 | 599篇 |
2000年 | 641篇 |
1999年 | 548篇 |
1998年 | 264篇 |
1997年 | 240篇 |
1996年 | 254篇 |
1995年 | 216篇 |
1994年 | 178篇 |
1993年 | 175篇 |
1992年 | 434篇 |
1991年 | 484篇 |
1990年 | 445篇 |
1989年 | 423篇 |
1988年 | 370篇 |
1987年 | 392篇 |
1986年 | 363篇 |
1985年 | 350篇 |
1984年 | 289篇 |
1983年 | 249篇 |
1982年 | 156篇 |
1981年 | 152篇 |
1980年 | 119篇 |
1979年 | 193篇 |
1978年 | 149篇 |
1977年 | 151篇 |
1976年 | 126篇 |
1974年 | 182篇 |
1973年 | 163篇 |
1972年 | 131篇 |
1970年 | 134篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
101.
102.
103.
W B Campbell H Decaluwe V Boecxstaens J A MacIntyre N Walker J F Thompson A R Cowan 《European journal of vascular and endovascular surgery》2007,34(6):741-744
OBJECTIVES: To investigate the activities which may exacerbate symptoms in patients with varicose veins. METHODS: Questionnaires sent to patients before clinics and at least six months later. RESULTS: Both questionnaires were returned by 149 of 203 patients (74%) but only 124 contained adequate data for comparison--55 from patients who had surgical treatment and 69 who had no surgery. At initial presentation, worsening of discomfort attributed to varicose veins was common during (58%) or after (48%) standing and in hot weather (44%), but less when sitting with the feet down (31%), and after (31%) or when walking (19%). Surgery significantly reduced the total number of symptoms reported by patients at follow-up (p<0.02). However, none of the symptoms reported during specific activities was significantly lessened by surgery compared with no treatment--possibly because the attrition of patients during the study resulted in small numbers for analysis. CONCLUSIONS: Symptoms are a common indication for treating varicose veins and it is therefore important to be sure that they are due to the veins, rather than other causes. This report highlights traditional and logical questions which may help to identify symptoms caused by varicose veins but illustrates the difficulty of validating them. 相似文献
104.
105.
106.
107.
Picotamide inhibition of excess in vitro thromboxane B2 release by colorectal mucosa in inflammatory bowel disease. 总被引:1,自引:0,他引:1
Collins CE Benson MJ Burnham WR Rampton DS 《Alimentary pharmacology & therapeutics》1996,10(3):315-320
BACKGROUND: Inflammatory bowel disease is associated with increased mucosal release of eicosanoids. Among these, thromboxane A2 has been proposed as a possible inflammatory mediator; its suppression may be a useful therapeutic option. METHODS: Using a tissue incubation technique, we compared release of immunoreactive thromboxane B2 by colonic biopsies from patients with ulcerative colitis, Crohn's disease and controls, and assessed the inhibitory effect of picotamide, a thromboxane synthesis inhibitor-receptor antagonist, which has been widely used in Italy for management of ischaemic heart and cerebrovascular disease. RESULTS: Increased amounts of thromboxane B2 were released from biopsies from patients with active ulcerative colitis (median 238 pg/20 min/mg wet weight (interquartile range 147- 325), n = 12) and active Crohn's disease (252 (174-450), 6) compared with those from patients with quiescent ulcerative colitis (95 (61- 140), 12) or Crohn's disease (105 (57-201), 13), or controls (136 (64- 206), 8). Incubation with picotamide at concentrations between 100 microM and 1 mM reduced thromboxane B2 release (IC50 890 microM). CONCLUSION: Since increased thromboxane A2 production may have pathogenetic importance, thromboxane synthesis inhibitor-receptor antagonists such as picotamide merit therapeutic trial in the management of inflammatory bowel disease. 相似文献
108.
109.
Anderson RA; Evans LW; Irvine DS; McIntyre MA; Groome NP; Riley SC 《Human reproduction (Oxford, England)》1998,13(12):3319-3325
Follistatin is a binding protein for the activin and inhibin family of
hormones, regulating their biological activity. In the male reproductive
tract, the interaction of these factors is likely to be involved in the
regulation of the proliferation of several cell types. We have investigated
the presence of follistatin and activin A in seminal plasma using specific
immunoassays and have localized follistatin and activin/inhibin subunits in
the adult human testis, prostate and seminal vesicle to establish their
likely sources. High concentrations of immunoreactive follistatin were
present in seminal plasma in normal men (mean 97.9 ng/ml; 1.43 ng/ml in
peripheral plasma) and were similar in men with oligo/azoospermia and
following vasectomy. Follistatin immunoreactivity was localized to both
Leydig and Sertoli cells of the testis, and to epithelial cells of the
prostate gland and seminal vesicle, which are likely to be the predominant
sources of the hormone in seminal plasma. Activin A was also present in
seminal plasma in normal men but was undetectable following vasectomy, thus
deriving from the testis. Consistent with this finding, the betaA-subunit
was immunolocalized in Sertoli and Leydig cells but was not present in
seminal vesicle or prostate gland. The functional significance of the high
concentrations of follistatin secreted into seminal plasma by the prostate
gland and/or seminal vesicle is uncertain, but they may regulate the
biological activity of testis-derived activin A and inhibin B.
相似文献
110.
OBJECTIVE. We evaluate whether patient outcomes may be affected by possible errors in care at discharge as assessed by Peer Review Organizations (PROs). DATA SOURCES/STUDY SETTING. The three data sources for the study were (1) the generic screen results of a 3 percent random sample of Medicare beneficiaries age 65 years or older who were admitted to California hospitals between 1 July 1987 and 30 June 1988 (n = 20,136 patients); (2) the 1987 and 1988 California Medicare Provided Analysis and Review (MEDPAR) data files; and (3) the American Hospital Association (AHA) 1988 Annual Survey of Hospitals. STUDY DESIGN. Multivariate logistic regression analysis was used to evaluate the association between the results of generic discharge administered by the PROs and two patient outcomes: mortality and readmission within 30 days. The analysis was adjusted for other patient characteristics recorded on the uniform discharge abstract. PRINCIPAL FINDINGS. Four discharge screens indicated an increased risk of an adverse outcome-absence of documentation of discharge planning, elevated temperature, abnormal pulse, and unaddressed abnormal test results at discharge. The other three discharge screens examined-abnormal blood pressure, IV fluids or drugs, and wound drainage before discharge-were unrelated to postdischarge adverse outcomes. CONCLUSIONS. Generic discharge screens based on inadequate discharge planning, abnormal pulse, increased temperature, or unaddressed abnormal tests may be important indicators of substandard care. Other discharge screens apparently do not detect errors in care associated with major consequences for patients. 相似文献