首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3891篇
  免费   586篇
  国内免费   14篇
耳鼻咽喉   43篇
儿科学   139篇
妇产科学   79篇
基础医学   493篇
口腔科学   53篇
临床医学   351篇
内科学   1100篇
皮肤病学   37篇
神经病学   420篇
特种医学   170篇
外科学   544篇
综合类   93篇
预防医学   478篇
眼科学   96篇
药学   226篇
肿瘤学   169篇
  2021年   43篇
  2019年   33篇
  2017年   34篇
  2015年   45篇
  2014年   53篇
  2013年   82篇
  2012年   121篇
  2011年   128篇
  2010年   79篇
  2009年   71篇
  2008年   110篇
  2007年   106篇
  2006年   122篇
  2005年   165篇
  2004年   129篇
  2003年   97篇
  2002年   111篇
  2001年   101篇
  2000年   94篇
  1999年   103篇
  1998年   48篇
  1997年   46篇
  1996年   57篇
  1995年   46篇
  1994年   56篇
  1993年   55篇
  1992年   107篇
  1991年   95篇
  1990年   120篇
  1989年   133篇
  1988年   125篇
  1987年   132篇
  1986年   135篇
  1985年   129篇
  1984年   119篇
  1983年   136篇
  1982年   79篇
  1981年   82篇
  1980年   80篇
  1979年   110篇
  1978年   85篇
  1977年   77篇
  1976年   49篇
  1975年   52篇
  1974年   49篇
  1973年   41篇
  1972年   46篇
  1971年   47篇
  1970年   48篇
  1969年   35篇
排序方式: 共有4491条查询结果,搜索用时 15 毫秒
101.
Molestation and rape in childhood or adulthood is sexual violence. This chapter discusses issues for sexual violence victims and suggests several best practices for this population.  相似文献   
102.
Episode-related factors and antidepressant treatment adequacy may be important determinants of recovery from a major depressive episode (MDE). We compared recovered and nonrecovered patients on baseline sociodemographic, clinical and episode-related measurements. Twenty-five inpatients with recurrent major depressive disorder diagnosed by SADS-L participated in this naturalistic, prospective, longitudinal study. Recovery, which was defined as a sustained return to non-depressed status lasting > or = 8 consecutive weeks, was assessed at 6- and 12-month follow-up with the Streamlined Longitudinal Interval Continuation Evaluation (SLICE). Thirteen (52%) patients met recovery criteria. The cumulative proportion remaining depressed for at least 52 weeks was 42.5%. Recovered patients had shorter episodes preceding the index hospitalization (P = .01). Despite adequate antidepressant pharmacotherapy, the length of the current episode remains the most important correlate of recovery from MDE recurrence. Our small sample size and the uncontrolled nature of treatment may limit the generalizability of these findings.  相似文献   
103.
Neutralization assays are experimental surrogates for the effectiveness of infection- or vaccine-elicited polyclonal antibodies and therapeutic monoclonal antibodies targeting SARS-CoV-2. However, the measured neutralization can depend on the details of the experimental assay. Here, we systematically assess how ACE2 expression in target cells affects neutralization by antibodies to different spike epitopes in lentivirus pseudovirus neutralization assays. For high ACE2-expressing target cells, receptor-binding domain (RBD) antibodies account for nearly all neutralizing activity in polyclonal human sera. However, for lower ACE2-expressing target cells, antibodies targeting regions outside the RBD make a larger (although still modest) contribution to serum neutralization. These serum-level results are mirrored for monoclonal antibodies: N-terminal domain (NTD) antibodies and RBD antibodies that do not compete for ACE2 binding incompletely neutralize on high ACE2-expressing target cells, but completely neutralize on cells with lower ACE2 expression. Our results show that the ACE2 expression level in the target cells is an important experimental variable, and that high ACE2 expression emphasizes the role of a subset of RBD-directed antibodies.  相似文献   
104.
ObjectiveTo assess the safety and efficacy of endocyclophotocoagulation with phacoemulsification (phaco-ECP) in surgically naive, primary open-angle glaucoma (POAG).MethodsA retrospective case series of patients undergoing phaco-ECP between 2007 and 2017 at a single centre in London, UK. The primary outcome was intraocular pressure (IOP). Secondary outcomes were visual acuity, visual field global indices, topical medications and surgical complications. Failure criteria were: (1) IOP > 21 mmHg or <20% reduction at two consecutive visits, (2) IOP <5 mmHg and (3) further IOP-lowering surgery.ResultsEighty-three eyes from 83 patients were eligible. Pre-operatively, mean IOP (±SD) was 18.4 ± 5.2 mmHg. The mean number of topical agents (±SD) was 2.7 ± 0.9. Mean IOP (±SD) significantly reduced to 14.3 ± 4.7 at 1 year, 14.1 ± 4.0 at 2 years and 13.6 ± 3.7 at 3 years (p < 0.0001). Topical medications were significantly reduced to 1.3 ± 1.2 at 1 year, 1.7 ± 1.2 at 2 years and 1.8 ± 1.3 at 3 years (p < 0.0001). Annual IOP ‘survival’ was 70%, 54% and 45% at year 1, 2 and 3, respectively. Complications included uveitis (6%), macular oedema (2%), IOP spikes (1%) and corneal decompensation (1%) with no episodes of hypotony or retinal detachment. One patient underwent filtration surgery within 3 years (1%).ConclusionPhaco-ECP facilitates significant IOP lowering and reduction of medication burden in surgically naive POAG requiring cataract extraction. The procedure is relatively safe and without the use of implants and their associated risks.Subject terms: Optic nerve diseases, Surgery  相似文献   
105.
106.
107.
108.
This plate should be substituted for the original Plate 8 which appeared in Vol. 86, No. 2, August l, 1947, and showed faulty register of the colors.  相似文献   
109.
1. The spontaneous mast cell tumor of the dog contains heparin. 2. The cytoplasmic particulate content of the tumor mast cells varies with their anaplasia. This conclusion is based on the following findings: (a) in the immature cell of the more malignant tumor the particulate matter appeared in the living cells by phase microscopy to be composed of greyish illdefined particles or as a fine, weakly metachromatic granulation in the fixed and stained preparation; (b) in the mature cells of a relatively benign mast cell tumor, both in the living cell and in stained preparations, the particulate matter occurred in the form of discrete, dense, and strongly metachromatic granules, resembling those of the normal mast cell. 3. The heparin content was large (fifty times that of dog liver) in the growth with mature cells and only moderate (1.7 times) in that with immature cells. 4. Since there may be a great amount of greyish particulate matter (or fine stained granules) in a tumor of relatively low heparin content, it is suggested that this material represents an early or precursor phase in the development of heparin. 5. This possibility and the fact that the blood stream may be invaded by mature tumor mast cells of large heparin content without evident disturbance in the coagulability of the blood suggest the value of a comprehensive biochemical study of the heparin of mast cell tumors.  相似文献   
110.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号